0001463101-22-000016 | 10-K | XBRL Viewer

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CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 119,316	$ 679,379
Marketable securities	897,335	0
Accounts receivable, net of allowances of $1,590 and $462 at December 31, 2021 and December 31, 2020, respectively	333,626	182,165
Inventory	74,400	41,764
Prepaid expenses and other assets	37,784	29,756
Total current assets	1,462,461	933,064
Property and equipment, net	82,167	42,985
Operating lease, right of use asset, net	14,420	17,683
Intangible assets, net	97,758	28,808
Goodwill	181,254	24,783
Other assets	118,726	59,875
Deferred tax assets, net	122,470	92,904
Total assets	2,079,256	1,200,102
Current liabilities:
Accounts payable	113,767	72,609
Accrued liabilities	157,912	76,542
Deferred revenues, current	62,670	47,665
Warranty obligations, current (includes $14,612 and $8,267 measured at fair value at December 31, 2021 and December 31, 2020, respectively)	19,395	11,260
Debt, current	86,052	325,967
Total current liabilities	439,796	534,043
Long-term liabilities:
Deferred revenues, non-current	187,186	125,473
Warranty obligations, non-current (includes $36,395 and $20,469 measured at fair value at December 31, 2021 and December 31, 2020, respectively)	53,982	34,653
Other liabilities	16,530	17,042
Debt, non-current	951,594	4,898
Total liabilities	1,649,088	716,109
Commitments and contingencies (Note 14)
Stockholders’ equity:
Common stock, $0.00001 par value, 300,000 shares and 200,000 shares authorized; and 133,894 shares and 128,962 shares issued and outstanding at December 31, 2021 and December 31, 2020, respectively	1	1
Additional paid-in capital	837,924	534,744
Accumulated deficit	(405,737)	(51,186)
Accumulated other comprehensive income (loss)	(2,020)	434
Total stockholders’ equity	430,168	483,993
Total liabilities and stockholders’ equity	$ 2,079,256	$ 1,200,102

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Accounts receivable, allowance	$ 1,590	$ 462
Product warranty, measured at fair value, current	14,612	8,267
Product warranty, measured at fair value, noncurrent	$ 36,395	$ 20,469
Common stock, par value (in usd per share)	$ 0.00001	$ 0.00001
Common stock, shares authorized (in shares)	300,000,000	200,000,000
Common stock, shares issued (in shares)	133,894,000	128,962,000
Common stock, shares outstanding (in shares)	133,894,000	128,962,000

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Net revenues	$ 1,382,049	$ 774,425	$ 624,333
Cost of revenues	827,627	428,444	403,088
Gross profit	554,422	345,981	221,245
Operating expenses:
Research and development	105,526	55,921	40,381
Sales and marketing	128,974	52,927	36,728
General and administrative	104,090	50,694	38,808
Restructuring charges	0	0	2,599
Total operating expenses	338,590	159,542	118,516
Income from operations	215,832	186,439	102,729
Other income (expense), net
Interest income	695	2,156	2,513
Interest expense	(45,152)	(21,001)	(9,691)
Other (expense) income, net	6,050	(799)	(5,437)
Loss on partial settlement of convertible notes	(56,497)	(3,037)	0
Change in fair value of derivatives	0	(44,348)	0
Total other expense, net	(94,904)	(67,029)	(12,615)
Income before income taxes	120,928	119,410	90,114
Income tax benefit	24,521	14,585	71,034
Net income	$ 145,449	$ 133,995	$ 161,148
Net income per share:
Basic (in USD per share)	$ 1.09	$ 1.07	$ 1.38
Diluted (in USD per share)	$ 1.02	$ 0.95	$ 1.23
Shares used in per share calculation:
Basic (in shares)	134,025	125,561	116,713
Diluted (in shares)	142,878	141,918	131,644

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 145,449	$ 133,995	$ 161,148
Other comprehensive income (loss):
Foreign currency translation adjustments	(334)	1,357	(1,665)
Marketable securities
Change in net unrealized loss	(2,120)	0	0
Less: reclassification adjustment for net losses included in net income	0	0	0
Net change, net of income tax benefit of $745	(2,120)	0	0
Comprehensive income	$ 142,995	$ 135,352	$ 159,483

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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+ Details

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($)
Statement of Comprehensive Income [Abstract]
Marketable Securities, income tax benefit	$ 745

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Additional Paid-In Capital	Additional Paid-In Capital Cumulative Effect, Period of Adoption, Adjustment	Accumulated deficit	Accumulated deficit Cumulative Effect, Period of Adoption, Adjustment	Accumulated other comprehensive income (loss)
Balance, beginning of period (in shares) at Dec. 31, 2018			107,035
Balance, beginning of period at Dec. 31, 2018	$ 7,776	$ 0	$ 1	$ 353,335	$ 27	$ (346,302)	$ (27)	$ 742
Issuance of common stock from exercise of equity awards and employee stock purchase plan (in shares)			5,273
Issuance of common stock from exercise of equity awards and employee stock purchase plan	4,985			4,985
Payment of withholding taxes related to net share settlement of equity awards	(8,198)			(8,198)
Conversion of convertible notes due 2023, net (in shares)			10,801
Settlement of convertible senior notes	58,857			58,857
Cost of convertible notes hedge related to the convertible senior notes, net	(36,313)			(36,313)
Sale of warrants related to the convertible senior notes	29,818			29,818
Equity component of settlement of convertible senior notes, net	35,387			35,387
Stock-based compensation	20,417			20,417
Net income	161,148					161,148
Foreign currency translation adjustments	(1,665)							(1,665)
Change in net unrealized loss on marketable securities, net of tax	0
Balance, ending of period (in shares) at Dec. 31, 2019			123,109
Balance, end of period at Dec. 31, 2019	272,212		$ 1	458,315		(185,181)		(923)
Issuance of common stock from exercise of equity awards and employee stock purchase plan (in shares)			4,002
Issuance of common stock from exercise of equity awards and employee stock purchase plan	8,395			8,395
Payment of withholding taxes related to net share settlement of equity awards	(68,330)			(68,330)
Conversion of convertible notes due 2023, net (in shares)			1,851
Settlement of convertible senior notes	301,015			301,015
Equity component of convertible senior notes, net	116,502			116,502
Cost of convertible notes hedge related to the convertible senior notes, net	(117,108)			(117,108)
Sale of warrants related to the convertible senior notes	96,351			96,351
Equity component of settlement of convertible senior notes, net	(306,220)			(306,220)
Exercise of convertible notes hedge related to the convertible senior notes (in shares)			(1,851)
Exercise of warrants related to convertible senior notes (in shares)			1,851
Change in fair value of common stock related to acquisition	3,321			3,321
Stock-based compensation	42,503			42,503
Net income	133,995					133,995
Foreign currency translation adjustments	1,357							1,357
Change in net unrealized loss on marketable securities, net of tax	$ 0
Balance, ending of period (in shares) at Dec. 31, 2020	128,962		128,962
Balance, end of period at Dec. 31, 2020	$ 483,993		$ 1	534,744		(51,186)		434
Issuance of common stock from exercise of equity awards and employee stock purchase plan (in shares)			2,808
Issuance of common stock from exercise of equity awards and employee stock purchase plan	7,484			7,484
Payment of withholding taxes related to net share settlement of equity awards (in shares)			0
Payment of withholding taxes related to net share settlement of equity awards	(29,136)			(29,136)
Equity component of convertible senior notes, net	207,970			207,970
Cost of convertible notes hedge related to the convertible senior notes, net	(213,322)			(213,322)
Sale of warrants related to the convertible senior notes	220,800			220,800
Equity component of settlement of convertible senior notes, net	(976,714)			(976,714)
Settlement of convertible senior notes (in shares)			5,489
Settlement of convertible senior notes	972,273			972,273
Exercise of convertible notes hedge related to the convertible senior notes (in shares)			(5,721)
Exercise of warrants related to convertible senior notes (in shares)			5,582
Stock-based compensation	113,825			113,825
Net income	145,449					145,449
Repurchase of common stock (in shares)			(3,226)
Repurchase of common stock	(500,000)					(500,000)
Foreign currency translation adjustments	(334)							(334)
Change in net unrealized loss on marketable securities, net of tax	$ (2,120)							(2,120)
Balance, ending of period (in shares) at Dec. 31, 2021	133,894		133,894
Balance, end of period at Dec. 31, 2021	$ 430,168		$ 1	$ 837,924		$ (405,737)		$ (2,020)

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities:
Net income	$ 145,449	$ 133,995	$ 161,148
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	32,439	18,103	14,119
Provision for doubtful accounts	477	425	217
Asset impairment	0	0	1,124
Non-cash interest expense	44,387	18,825	6,081
Financing fees on extinguishment of debt	0	0	2,152
Fees paid for repurchase and exchange of convertible notes due 2023	0	0	6,000
Loss on partial settlement of convertibles notes	56,497	3,037	0
Deemed repayment of convertible notes attributable to accreted debt discount	(15,718)	(3,132)	0
Gain on settlement of debt securities	(6,569)	0	0
Change in fair value of debt securities	(3,042)	0	0
Stock-based compensation	114,286	42,503	20,176
Change in fair value of derivatives	0	44,348	0
Deferred income taxes	(31,241)	(17,117)	(73,375)
Changes in operating assets and liabilities:
Accounts receivable	(151,160)	(34,321)	(68,745)
Inventory	(29,258)	(9,708)	(15,789)
Prepaid expenses and other assets	(26,885)	(14,636)	(14,293)
Accounts payable, accrued and other liabilities	117,183	35,695	22,200
Warranty obligations	27,016	8,815	5,804
Deferred revenues	78,167	(10,498)	72,248
Net cash provided by operating activities	352,028	216,334	139,067
Cash flows from investing activities:
Purchases of property and equipment	(52,258)	(20,558)	(14,788)
Purchase of intangible asset	(250)	0	0
Investments in private companies	(58,000)	(5,010)	0
Redemption of investment in private companies	26,569	0	0
Business acquisitions, net of cash acquired	(235,652)	0	0
Purchases of marketable securities	(934,956)	0	0
Maturities of marketable securities	35,000	0	0
Net cash used in investing activities	(1,219,547)	(25,568)	(14,788)
Cash flows from financing activities:
Issuance of convertible notes, net of issuance costs	1,188,439	312,420	127,413
Purchase of convertible note hedges	(286,235)	(89,056)	(36,313)
Sale of warrants	220,800	71,552	29,818
Fees paid for repurchase and exchange of convertible notes due 2023	0	0	(6,000)
Principal payments and financing fees on debt	(1,694)	(2,575)	(45,855)
Partial repurchase of convertible notes	(290,247)	(40,728)	0
Proceeds from exercise of equity awards and employee stock purchase plan	7,484	8,395	4,985
Repurchase of common stock	(500,000)	0	0
Payment of withholding taxes related to net share settlement of equity awards	(29,136)	(68,330)	(8,198)
Net cash provided by financing activities	309,411	191,678	65,850
Effect of exchange rate changes on cash and cash equivalents	(1,955)	826	(257)
Net increase (decrease) in cash, cash equivalents and restricted cash	(560,063)	383,270	189,872
Cash, cash equivalents and restricted cash—Beginning of period	679,379	296,109	106,237
Cash, cash equivalents and restricted cash—End of period	119,316	679,379	296,109
Reconciliation of cash, cash equivalents, and restricted cash to the consolidated balance sheets
Cash and cash equivalents	119,316	679,379	251,409
Restricted cash	0	0	44,700
Total cash, cash equivalents, and restricted cash	119,316	679,379	296,109
Supplemental Cash Flow Information [Abstract]
Cash paid for interest	733	1,875	2,689
Cash paid for income taxes	4,823	3,452	1,755
Supplemental disclosures of non-cash investing and financing activities:
Purchases of fixed assets included in accounts payable	7,498	3,630	672
Contingent consideration in connection with the acquisition	3,500	0	0
Accrued interest payable unpaid upon exchange of convertible notes due 2023	$ 0	$ 0	$ 833

DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION	12 Months Ended
DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION	DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION Description of Business Enphase Energy, Inc. (the “Company”) is a global energy technology company. The Company delivers smart, easy-to-use solutions that manage solar generation, storage and communication on one platform. The Company revolutionized the solar industry with its microinverter technology and produces a fully integrated solar-plus-storage solution. Basis of Presentation and Consolidation The accompanying consolidated financial statements are presented in accordance with accounting principles generally accepted in the United States (“U.S.”), or GAAP. The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of income and expenses during the reporting period. Significant estimates and assumptions reflected in the financial statements include revenue recognition, allowance for doubtful accounts, stock-based compensation, deferred compensation arrangements, inventory valuation, accrued warranty obligations, fair value of investments, debt derivatives, convertible notes and contingent consideration, fair value of acquired intangible assets and goodwill, useful lives of acquired intangible assets and property and equipment, incremental borrowing rate for right-of-use assets and lease liability, legal contingencies, and tax valuation allowance. These estimates are based on information available as of the date of the financial statements; therefore, actual results could differ materially from those estimates due to risks and uncertainties, including uncertainty in the ongoing semiconductor supply and logistics constraints, and the evolving COVID-19 pandemic.

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

12 Months Ended

Dec. 31, 2021

Accounting Policies [Abstract]

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Revenue Recognition

The Company generates revenue from sales of its solutions, which include microinverter units and related accessories, an Envoy communications gateway, the cloud-based Enlighten monitoring service, storage solutions, Electric Vehicle (“EV”) charging solutions beginning in the first quarter of 2022, design, proposal and permitting services, as well as a platform matching cleantech asset owners to a local and on-demand workforce of service providers, to distributors, large installers, OEMs and strategic partners.

Revenues are recognized when control of the promised goods or services are transferred to the Company’s customers in an amount that reflects the consideration that is expected to be received in exchange for those goods or services. The Company generates all of its revenues from contracts with its customers. A description of principal activities from which the Company generates revenues follows.

•Products Delivered at a Point in Time. The Company sells its products and professional services to customers in accordance with the terms of the related customer contracts. The Company generates revenues from sales of its solutions, which include microinverter units and related accessories, an Envoy communications gateway and Enlighten service, communications accessories, storage solutions, EV charging solutions beginning in the first quarter of 2022, design, proposal and permitting services, as well as a platform matching cleantech asset owners to a local and on-demand workforce of service providers to distributors, large installers, OEMs and strategic partners. Microinverter units, microinverter accessories, storage and EV solutions, design, proposal and permitting services, as well as completed work orders on its platform matching cleantech asset owners to a local and on-demand workforce of service providers, are delivered to customers at a point in time, and the Company recognizes revenue for these products or professional services when the Company transfers control of the product or

professional services to the customer, which is generally upon product shipment or service delivery, respectively.

•Products Delivered Over Time. The sale of an Envoy communications gateway includes the Company’s Enlighten cloud-based monitoring service. The full consideration for these products represents a single performance obligation and is deferred at the sale date and recognized over the estimated service period of 6 years. The Company also sells certain communication accessories that contain a service performance obligation to be delivered over time. The revenue from these products is recognized over the related service period, which is typically 5 or 12 years. The subscription services revenue generated from each customer’s subscription to the Company’s design and proposal software is recognized on a ratable basis over the contract term beginning on the date that the Company’s service is made available to the customer. The subscription contracts are generally three to twelve months in length and billed in advance.

When the Company sells a product with more than one performance obligation, such as the IQ Combiner which includes both hardware and Envoy, the total consideration is allocated to these performance obligations based on their relative standalone selling prices.

The Company records certain contra revenue promotions as variable consideration and recognizes these promotions at the time the related revenue is recorded.

The Company records upfront contract acquisition costs, such as sales commissions, to be capitalized and amortized over the estimated life of the asset. For contracts that have a duration of less than one year, the Company follows the Topic 606 practical expedient and expenses these costs when incurred. Commissions related to the Company’s sale of monitoring hardware and service are capitalized and amortized over the period of the associated revenue, which is 6 years.

See Note 3 . “Revenue Recognition,” for additional information related to revenue recognition.

Cost of Revenues

The Company includes the following in cost of revenues: product costs, warranty, manufacturing personnel and logistics costs, freight costs, inventory write-downs, hosting services costs related to the Company’s Enlighten service offering and design and proposal services, depreciation and amortization of manufacturing test equipment and amortization of capitalized software development costs related to the Company’s Enlighten service offering, design and proposal services, and employee-related expenses associated with proposal and permitting services and design and proposal service customer support. A description of principal activities from which the Company recognizes cost of revenue is as follows.

•Products Delivered at a Point in Time. Cost of revenue from these products is recognized when the Company transfers control of the product to the customer, which is generally upon shipment.

•Products Delivered Over Time. Cost of revenue from these products is recognized over the related service period.

Cash, Cash Equivalents and Marketable Securities

The Company classifies investments in marketable securities as available-for-sale investments and records these marketable securities at fair value. The Company determines the appropriate classification of marketable securities at the time of purchase and reevaluates such designation at each balance sheet date. All highly liquid investments with original maturities of 90 days or less from the date of purchase are classified as cash equivalents, while all others are presented within current assets since these investments represent funds available for current operations and the Company has the ability and intent, if necessary, to liquidate any of these investments within one year in order to meet liquidity needs or to grow the business, including for potential business acquisitions or other strategic transactions.

Marketable securities are recorded at fair value, with the unrealized gains or losses unrelated to credit loss factors included in accumulated other comprehensive income (loss), net of tax. Realized gains and losses and declines in value determined to be other than temporary based on the specific identification method are reported in other income (expense), net in the consolidated statements of operations.

The Company periodically reviews whether the securities may be other-than-temporarily impaired, including whether or not (i) the Company has the intent to sell the security or (ii) it is more likely than not that the Company will be required to sell the security before its anticipated recovery. If one of these factors is met, the Company records an impairment loss associated with the impaired investment. The impairment loss will be recorded as a write-down of investments in the consolidated balance sheets and a realized loss within other income (expense), net in the consolidated statements of operations. There were no credit-related impairments recognized on the Company’s investments in marketable securities during the periods presented.

For purposes of identifying and measuring impairment, the policy election was made to exclude the applicable accrued interest from both the fair value and amortized cost basis. Applicable accrued interest of $2.1 million, net of the allowance for credit losses, if any, is recorded in prepaid expenses and other current assets on the consolidated balance sheets as of December 31, 2021.

Fair Value of Financial Instruments

The fair value of a financial instrument is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The carrying amounts of the Company’s cash and cash equivalents, accounts receivable, accounts payable and accrued liabilities approximate fair value because of the short maturity of those instruments. Equity investments with readily determinable fair value are carried at fair value based on quoted market prices or estimated based on market conditions and risks existing at each balance sheet date. Equity investments without readily determinable fair value are measured at cost less impairment, and are adjusted for observable price changes in orderly transactions for an identical or similar investment of the same issuer.

Convertible Note Derivatives

In March 2020, the Company issued $320.0 million aggregate principal amount of its 0.25% convertible senior notes due 2025 (the “Notes due 2025”). Concurrently with the issuance of Notes due 2025, the Company entered into privately-negotiated convertible note hedge and warrant transactions which in combination are intended to reduce the potential dilution from the conversion of the Notes due 2025. The Company could not elect to issue the shares of common stock upon settlement of Notes due 2025 or convertible note hedge or warrant transactions due to insufficient authorized share capital. As a result, the embedded conversion option and warrants were accounted for as derivative liabilities and convertible notes hedge as a derivative asset and a gain (or loss) was reported in other expense, net in the consolidated statement of operations to the extent the valuation changed from the date of issuance of Notes due 2025. On May 20, 2020, at the Company’s annual meeting of stockholders, the stockholders approved an amendment to its certificate of incorporation to increase the number of authorized shares of the Company’s common stock. As a result, the Company is now able to settle the Notes due 2025, convertible notes hedge and warrants through payment or delivery, as the case may be, of cash, shares of its common stock or a combination thereof, at the Company’s election. Accordingly, on May 20, 2020, the embedded derivative liability, convertible notes hedge and warrants liability were remeasured at a fair value and were then reclassified to additional paid-in-capital in the consolidated balance sheet in the second quarter of 2020 and are no longer remeasured as long as they continue to meet the conditions for equity classification. As of both December 31, 2021 and 2020, the Company does not have any convertible note derivatives. See Note 13. “Debt,” for additional information related to these transactions.

Accounts Receivables and Contract Assets

The Company receives payments from customers based upon contractual billing schedules. Accounts receivable are recorded when the right to consideration becomes unconditional. Contract assets include deferred product costs and commissions associated with the deferred revenue and will be amortized along with the associated revenue.

Allowance for Doubtful Accounts

The Company maintains allowances for doubtful accounts for uncollectible accounts receivable. Management estimates anticipated credit losses from doubtful accounts based on days past due, customer specific experience, collection history, the financial health of customers including from the impacts of the COVID-19 pandemic, among other factors. Accounts receivable are recorded net of allowance for doubtful accounts. The following table sets forth activities in the allowance for doubtful accounts for the periods indicated.


	December 31,
	2021		2020		2019
	(In thousands)
Balance, at beginning of year	$	462	$	564	$	2,138
Net charges to expense or reduction in revenue	1,140		425		217
Write-offs, net of recoveries	(12)		(527)		(1,791)
Balance, at end of year	$	1,590	$	462	$	564

Inventory

Inventory is valued at the lower of cost or market. Market is current replacement cost (by purchase or by reproduction, dependent on the type of inventory). In cases where market exceeds net realizable value (i.e., estimated selling price less reasonably predictable costs of completion and disposal), inventories are stated at net realizable value. Market is not considered to be less than net realizable value reduced by an allowance for an approximately normal profit margin. The Company determines cost on a first-in first-out basis. Management assesses the valuation on a quarterly basis and writes down the value for any excess and obsolete inventory based upon expected demand, anticipated sales price, effect of new product introductions, product obsolescence, customer concentrations, product merchantability and other factors. Inventory write-downs are equal to the difference between the cost of inventories and market.

Long-Lived Assets

Property and equipment are stated at cost less accumulated depreciation. Cost includes amounts paid to acquire or construct the asset as well as any expenditure that substantially adds to the value of or significantly extends the useful life of an existing asset. Repair and maintenance costs are expensed as incurred. Depreciation and amortization are computed using the straight-line method over the estimated useful lives of the assets, which range from 3 to 10 years. Leasehold improvements are amortized over the shorter of the lease term or expected useful life of the improvements.

Internal-use software, whether purchased or developed, is capitalized at cost and amortized on a straight-line basis over its estimated useful life. Costs associated with internally developed software are expensed until the point at which the project has reached the development stage. Subsequent additions, modifications or upgrades to internal-use software are capitalized only to the extent that they provide additional functionality. Software maintenance and training costs are expensed in the period in which they are incurred. The capitalization of internal-use software requires judgment in determining when a project has reached the development stage and the period over which the Company expects to benefit from the use of that software.

The Company capitalizes implementation costs related to cloud computing (i.e. hosting) arrangements that are accounted for as a service contract that meets the accounting requirement for capitalization as such implementation costs were incurred to develop or utilize internal-use software hosted by a third party vendor. The capitalized implementation costs are recorded as part of “Other assets” on the consolidated balance sheet and is amortized over the length of the service contract.

Property, plant and equipment, including internal-use software, and capitalized implementation costs related to cloud computing arrangements, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset (asset group) may not be recoverable. An impairment loss would be recognized when the carrying amount of an asset exceeds the estimated undiscounted future cash flows expected to result from the use of the asset and its eventual disposition. The amount of the impairment loss to be recorded is calculated by the excess of the asset’s carrying value over its fair value. Fair value is generally determined using a discounted cash flow analysis. The Company recorded asset impairment charges for specific assets that were no longer in use of approximately zero, zero and $1.1 million for the years ended 2021, 2020 and 2019, respectively. There were no events or changes in circumstances that may indicate the carrying amount of remaining assets is not recoverable.

Business Combinations

Assets acquired and liabilities assumed as part of a business acquisition are generally recorded at their fair value at the date of acquisition. The excess of purchase price over the fair value of assets acquired and liabilities assumed is recorded as goodwill. Determining fair value of identifiable assets, particularly intangibles, and liabilities acquired also requires the Company to make estimates, which are based on all available information and in some cases assumptions with respect to the timing and amount of future revenues and expenses associated with an asset. Accounting for business acquisitions requires the Company to make judgments as to whether a purchase transaction is a multiple element contract, meaning that it includes other transaction components. This judgment and determination affect the amount of consideration paid that is allocable to assets and liabilities acquired in the business purchase transaction. Additional information existing as of the acquisition date but unknown to the Company may become known during the remainder of the measurement period, not to exceed 12 months from the acquisition date, which may result in changes to the amounts and allocations recorded.

Goodwill

Goodwill results from the purchase consideration paid in excess of the fair value of the net assets recorded in connection with business acquisitions. Goodwill is not amortized but is assessed for potential impairment at least annually during the fourth quarter of each fiscal year or between annual tests if an event occurs or circumstances change that would indicate the carrying amount may be impaired. Goodwill is tested at the reporting unit level, which the Company has determined to be the same as the entity as a whole (entity level). The Company first performs qualitative assessment to determine whether it is more likely than not that the fair value of our reporting unit is less than its carrying value. If, after assessing the qualitative factors, we determine that it is more likely than not that the fair value of our reporting unit is less than its carrying value, an impairment analysis will be performed.

Qualitative factors include industry and market consideration, overall financial performance, share price trends and market capitalization and Company-specific events. The Company determined, after performing a qualitative review of its reporting unit, that it is more likely than not that the fair value of our reporting unit exceeds its carrying value. Accordingly, there was no indication of impairment in the years ended 2021, 2020 and 2019 and no quantitative goodwill impairment test was performed.

Intangible Assets

Intangible assets include patents and other purchased intangible assets. Intangible assets with finite lives are amortized on a straight-line basis, with estimated useful lives ranging from 5 to 9 years. Indefinite-lived intangible assets are tested for impairment annually and are also tested for impairment between annual tests if an event occurs or circumstances change that would indicate that the carrying amount may be impaired. Intangible assets with finite lives are tested for impairment whenever events or circumstances indicate that the carrying amount of an asset (asset group) may not be recoverable. An impairment loss is recognized when the carrying amount of an asset exceeds the estimated undiscounted cash flows used in determining the fair value of the asset. The amount of the impairment loss to be recorded is calculated by the excess of the asset’s carrying value over its fair value. Fair value is generally determined using a discounted cash flow analysis. There was no impairment of intangible assets in any of the years presented.

Contract Liabilities

Contract liabilities are recorded as deferred revenue on the accompanying consolidated balance sheets and include payments received in advance of performance obligations under the contract and are realized when the associated revenue is recognized under the contract.

Warranty Obligations

Microinverters and Other Products Sold Through December 31, 2013

The Company’s warranty accrual provides for the replacement of microinverter units or other products that fail during the product’s warranty term (typically 15 years for first and second generation microinverters and up to 25 years for subsequent generation microinverters). On a quarterly basis, the Company employs a consistent, systematic and rational methodology to assess the adequacy of its warranty liability. This assessment includes updating all key estimates and assumptions for each generation of product, based on historical results, trends and the most current data available as of the filing date. The key estimates and assumptions used in the warranty liability are thoroughly reviewed by management on a quarterly basis. The key estimates used by the Company to estimate its warranty liability are: (1) the number of units expected to fail over time (i.e., failure rate); (2) the number of failed units expected to result in warranty claims over time (i.e., claim rate); and (3) the per unit cost of replacement units, including outbound shipping and limited labor costs, expected to be incurred to replace failed units over time (i.e., replacement cost).

Estimated Failure Rates — The Company’s Quality and Reliability department has primary responsibility to determine the estimated failure rates for each generation of microinverter. To establish initial failure rate estimates for each generation of microinverter, the Company’s quality engineers use a combination of industry standard Mean Time Between Failure (“MTBF”) estimates for individual components contained in its microinverters, third party data collected on similar equipment deployed in outdoor environments similar to those in which the Company’s microinverters are installed, and rigorous long term reliability and accelerated life cycle testing which simulates the service life of the microinverter in a short period of time. As units are deployed into operating environments, the Company continues to monitor product performance through its Enlighten monitoring platform. It typically takes three to nine months between the date of sale and date of end-user installation. Consequently, the Company’s ability to monitor actual failures of units sold similarly lags by three to nine months. When a microinverter fails and is returned, the Company performs diagnostic root cause failure analysis to understand and isolate the underlying mechanism(s) causing the failure. The Company then uses the results of this analysis (combined with the actual, cumulative performance data collected on those units prior to failure through Enlighten) to draw conclusions with respect to how or if the identified failure mechanism(s) will impact the remaining units deployed in the installed base.

Estimated Claim Rates — Warranty claim rate estimates are based upon observed historical trends and assumptions with respect to expected customer behavior over the warranty period. As the vast majority of the Company’s microinverters have been sold to end users for residential applications, the Company believes that warranty claim rates will be affected by changes over time in residential home ownership because the Company expects that subsequent homeowners are less likely to file claims than the homeowners who originally purchase the microinverters.

Estimated Replacement Costs — Three factors are considered in the Company’s analysis of estimated replacement cost: (1) the estimated cost of replacement microinverters; (2) the estimated cost to ship replacement microinverters to end users; and (3) the estimated labor reimbursement expected to be paid to third party installers performing replacement services for the end user. Because the Company’s warranty provides for the replacement of defective microinverters over long periods of time (between 15 and 25 years, depending on the generation of product purchased), the estimated per unit cost of current and future product generations is considered in the estimated replacement cost. Estimated costs to ship replacement units are based on observable, market-based shipping costs paid by the Company to third party freight carriers. The Company has a separate program that allows third-party installers to claim fixed-dollar reimbursements for labor costs they incur to replace failed microinverter units for a limited time from the date of original installation. Included in the Company’s estimated replacement cost is an analysis of the number of fixed-dollar labor reimbursements expected to be claimed by third party installers over the limited offering period.

In addition to the key estimates noted above, the Company also compares actual warranty results to expected results and evaluates any significant differences. Management may make additional adjustments to the warranty provision based on performance trends or other qualitative factors. If actual failure rates, claim rates, or replacement costs differ from the Company’s estimates in future periods, changes to these estimates may be required, resulting in increases or decreases in the Company’s warranty obligations. Such increases or decreases could be material.

Fair Value Option for Microinverters and Other Products Sold Since January 1, 2014

The Company’s warranty obligations related to microinverters sold since January 1, 2014 provide the Company the right, but not the requirement, to assign its warranty obligations to a third-party. Under Accounting Standards Codification (“ASC”) 825, “Financial Instruments” (also referred to as “fair value option”), an entity may choose to elect the fair value option for such warranties at the time it first recognizes the eligible item. The Company made an irrevocable election to account for all eligible warranty obligations associated with microinverters sold since January 1, 2014 at fair value. This election was made to reflect the underlying economics of the time value of money for an obligation that will be settled over an extended period of up to 25 years.

The Company estimates the fair value of warranty obligations by calculating the warranty obligations in the same manner as for sales prior to January 1, 2014 and applying an expected present value technique to that result. The expected present value technique, an income approach, converts future amounts into a single current discounted amount. In addition to the key estimates of failure rates, claim rates and replacement costs, the Company used certain inputs that are unobservable and significant to the overall fair value measurement. Such additional assumptions included compensation comprised of a profit element and risk premium required of a market participant to assume the obligation and a discount rate based on the Company’s credit-adjusted risk-free rate. See Note 11. “Fair Value Measurements,” for additional information.

Warranty obligations initially recorded at fair value at the time of sale will be subsequently re-measured to fair value at each reporting date. In addition, the fair value of the liability will be accreted over the corresponding term of the warranty of up to 25 years using the interest method.

Warranty for Other Products

The Company offers a 5‑year warranty for its Envoy communications gateway and a 10‑year warranty on its AC Battery storage solution. The warranties provide the Company with the right, but not the obligation, to assign its warranty obligations to a third-party. As such, warranties for Envoy and AC Battery storage solution products are accounted for under the fair value method of accounting.

Commitments and Contingencies

In the normal course of business, the Company is subject to loss contingencies and loss recoveries, such as legal proceedings and claims arising out of its business as well as tariff refunds. An accrual for a loss contingency or loss recovery is recognized when it is probable and the amount of loss or recovery can be reasonably estimated.

Advertising Costs

Advertising costs, which are expensed and included in sales and marketing expense when incurred, were $16.2 million, $0.8 million and $0.6 million during the years ended December 31, 2021, 2020 and 2019, respectively.

Research and Development Costs

The Company expenses research and development costs as incurred. Research and development expense consists primarily of product development personnel costs, including salaries and benefits, stock-based compensation, other professional costs and allocated facilities costs.

Stock-Based Compensation

Share-based payments are required to be recognized in the Company’s consolidated statements of operations based on their fair values and the estimated number of shares expected to vest. The Company measures stock-based compensation expense for all share-based payment awards, including stock options made to employees and directors, based on the estimated fair values on the date of the grant. The fair value of stock options granted is estimated using the Black-Scholes option valuation model. The fair value of restricted stock units granted is determined based on the price of the Company’s common stock on the date of grant. The fair value of non-market‑based performance stock units granted is determined based on the date of grant or when achievement of performance is probable. The fair value of market‑based performance stock units granted is determined using a Monte‑Carlo model based on the date of grant or when achievement of performance is probable.

Stock-based compensation for stock options and restricted stock units (“RSUs”) is recognized on a straight-line basis over the requisite service period. Stock-based compensation for performance stock units (“PSUs”) without market conditions is recognized when the performance condition is probable of being achieved, and then on a graded basis over the requisite service period. Stock-based compensation for PSUs with market conditions is recognized on a straight-line basis over the requisite service period. Additionally, the Company estimates its forfeiture rate annually based on historical experience and revise the estimates of forfeiture in subsequent periods if actual forfeitures differ from those estimates.

Common Stock Repurchase

The Company accounts for repurchase of common stock under ASC 505 and charges the entire cost of repurchase to the accumulated deficit.

Leases

The Company determines if an arrangement is or contains a lease at inception. Operating lease assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments over the lease term.

Operating lease assets and liabilities are recognized based on the present value of the remaining lease payments discounted using the Company’s incremental borrowing rate. Operating lease assets also include initial direct costs incurred and prepaid lease payments, minus any lease incentives. The Company’s lease terms include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Lease expense is recognized on a straight-line basis over the lease term.

The Company combines the lease and non-lease components in determining the operating lease assets and liabilities.

Foreign Currency Translation

The Company and most of its subsidiaries use their respective local currency as their functional currency. Accordingly, foreign currency assets and liabilities are translated using exchange rates in effect at the end of the period. Aggregate exchange gains and losses arising from the translation of foreign assets and liabilities are included in accumulated other comprehensive income (loss) in stockholders' equity. Foreign subsidiaries that use the U.S. dollar as their functional currency remeasure monetary assets and liabilities using exchange rates in effect at the end of the period. In addition, transactions that are denominated in non-functional currency are remeasured using exchange rates in effect at the end of the period. Exchange gains and losses arising from the remeasurement of monetary assets and liabilities are included in other income (expense), net in the consolidated statements of operations. Non-monetary assets and liabilities are carried at their historical values.

Comprehensive Income (Loss)

Comprehensive income (loss) consists of two components, net income (loss) and other comprehensive income (loss). Other comprehensive income (loss) refers to gains and losses that are recorded as an element of stockholders’ equity but are excluded from net income (loss). The Company’s other comprehensive income (loss) consists of foreign currency translation adjustments and change in net unrealized gain (loss) on marketable securities, net of tax.

Income Taxes

The Company records income taxes using the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected tax consequences of temporary differences between the tax bases of assets and liabilities for financial reporting purposes and amounts recognized for income tax purposes. In estimating future tax consequences, generally all expected future events other than enactments or changes in the tax law or rates are considered. Valuation allowances are provided when necessary to reduce deferred tax assets to the amount expected to be realized.

The Company assesses the realizability of the deferred tax assets to determine release of valuation allowance as necessary. In the event the Company determines that it is more likely than not that we would be able to realize deferred tax assets in the future in excess of our net recorded amount, an adjustment to the valuation allowance for the deferred tax asset would increase income in the period such determination was made. Likewise, should it be determined that additional amounts of the net deferred tax asset will not be realized in the future, an adjustment to increase the deferred tax asset valuation allowance will be charged to income in the period such determination is made.

The Company operates in various tax jurisdictions and is subject to audit by various tax authorities. The Company follows accounting for uncertainty in income taxes which requires that the tax effects of a position be recognized only if it is “more likely than not” to be sustained based solely on its technical merits as of the reporting date. The Company considers many factors when evaluating and estimating its tax positions and tax benefits, which may require periodic adjustments and which may not accurately anticipate actual outcomes.

Recently Issued Accounting Pronouncements

Not Yet Effective

In August 2020, the FASB issued Accounting Standards Update (“ASU”) 2020-06, “Debt - Debt with Conversion and Other Options (subtopic 470-20) and Derivatives and Hedging - Contracts in Entity’s Own Equity (subtopic 815-40),” which reduces the number of accounting models in ASC 470-20 that require separate accounting for embedded conversion features. As a result, a convertible debt instrument will be accounted for as a single liability measured at its amortized cost as long as no other features require bifurcation and recognition as derivatives. By removing those separation models, the effective interest rate of convertible debt instruments will be closer to the coupon interest rate. Further, the diluted net income per share calculation for convertible instruments will require the Company to use the if-converted method. The treasury stock method should no longer be used to calculate diluted net income per share for convertible instruments. The Company will adopt the new guidance in the annual period beginning January 1, 2022, on a modified retrospective basis. On the date of adoption, the Company expects to record a net decrease to additional paid-in capital by approximately $207.9 million, net of tax to remove the equity component separately recorded for the conversion features associated with the convertible debt instruments and equity component associated with the issuance costs, an increase of approximately $244.5 million in the carrying value of its convertible debt instrument to reflect the full principal amount of the Notes outstanding net of issuance costs, a decrease to deferred tax liability of approximately $62.3 million, and a decrease of approximately $25.7 million, net of tax to accumulated deficit. These estimates could change as the Company continues to progress with the implementation of the standard.

In October 2021, the FASB issued ASU 2021-08, "Business Combinations (Topic 805): Accounting for Contract Assets and Contract Liabilities from Contracts with Customers" (“ASU 2021-08”). The standard requires an acquirer in a business combination to recognize and measure contract assets and contract liabilities acquired in a business combination in accordance with ASC 606, Revenue from Contracts with Customers, as if it had originated the contracts. The standard is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2022. Early adoption is permitted. The Company does not expect the adoption of ASU 2021-08 to have a significant impact on its consolidated financial statements and plans to adopt the standard effective January 1, 2023.

REVENUE RECOGNITION

12 Months Ended

Dec. 31, 2021

Revenue from Contract with Customer [Abstract]

REVENUE RECOGNITION

Disaggregated Revenue

The Company has one major business activity, which is the design, manufacture and sale of solutions for the solar photovoltaic (“PV”) industry. Disaggregated revenue by primary geographical market and timing of revenue recognition for the Company’s single product line are as follows:


	Years Ended December 31,
		2021		2020
		(In thousands)
Primary geographical markets:
U.S.		$	1,108,801	$	637,879




International		273,248		136,546
Total		$	1,382,049	$	774,425

Timing of revenue recognition:
Products delivered at a point in time		$	1,323,960	$	728,254
Products and services delivered over time		58,089		46,171
Total		$	1,382,049	$	774,425

Contract Balances

Receivables, and contract assets and contract liabilities from contracts with customers are as follows:


	December 31, 2021		December 31, 2020
	(In thousands)
Receivables	$	333,626	$	182,165

Short-term contract assets (Prepaid expenses and other assets)	23,508		17,879
Long-term contract assets (Other assets)	69,583		51,986



Short-term contract liabilities (Deferred revenues, current)	62,670		47,665
Long-term contract liabilities (Deferred revenues, non-current)	187,186		125,473

Significant changes in the balances of contract assets (prepaid expenses and other assets) as of December 31, 2021 are as follows (in thousands):


Contract Assets
Contract Assets, beginning of period	$	69,865
Amount recognized	(21,894)
Increase	45,120
Contract Assets, end of period	$	93,091

Significant changes in the balances of contract liabilities (deferred revenues) as of December 31, 2021 are as follows (in thousands):


Contract Liabilities
Contract Liabilities, beginning of period	$	173,138
Revenue recognized	(64,793)

Increase due to billings	141,511

Contract Liabilities, end of period	$	249,856

Remaining Performance Obligations

Estimated revenue expected to be recognized in future periods related to performance obligations that are unsatisfied or partially unsatisfied at the end of the reporting period are as follows:


	December 31, 2021
	(In thousands)
Fiscal year:
2022	$	62,671
2023	55,497
2024	50,300
2025	43,362
2026	27,607
Thereafter	10,419
Total	$	249,856

- Definition

The entire disclosure of revenue from contract with customer to transfer good or service and to transfer nonfinancial asset. Includes, but is not limited to, disaggregation of revenue, credit loss recognized from contract with customer, judgment and change in judgment related to contract with customer, and asset recognized from cost incurred to obtain or fulfill contract with customer. Excludes insurance and lease contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-URI http://asc.fasb.org/topic&trid=49130388

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130551-203045

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130556-203045

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130554-203045

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130550-203045

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130554-203045

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130554-203045

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130554-203045

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130558-203045

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130554-203045

+ Details

INVENTORY

12 Months Ended

Dec. 31, 2021

Inventory Disclosure [Abstract]

INVENTORY

Inventory consists of the following:



	December 31, 2021		December 31, 2020
	(In thousands)
Raw materials	$	25,429	$	10,140
Finished goods	48,971		31,624
Total inventory	$	74,400	$	41,764

PROPERTY AND EQUIPMENT, NET

12 Months Ended

Dec. 31, 2021

Property, Plant and Equipment [Abstract]

PROPERTY AND EQUIPMENT, NET

Property and equipment consist of the following:


	Estimated Useful Life	December 31,
		2021		2020
	(Years)	(In thousands)
Equipment and machinery	3-10	$	95,365	$	63,411
Furniture and fixtures	5-10	3,197		2,532
Computer equipment	3-5	5,861		2,972
Capitalized software costs	3-5	28,118		17,004
Building and leasehold improvements	3-10	12,546		9,021
Land		114		—
Construction in process		14,332		9,747
Total		159,533		104,687
Less accumulated depreciation and amortization		(77,366)		(61,702)
Property and equipment, net		$	82,167	$	42,985

Depreciation expense for property and equipment for the years ended December 31, 2021, 2020 and 2019 was $16.7 million, $9.7 million and $7.3 million, respectively.

As of December 31, 2021 and 2020, unamortized capitalized software costs were $12.6 million and $4.8 million, respectively.

BUSINESS COMBINATION

12 Months Ended

Dec. 31, 2021

Business Combination and Asset Acquisition [Abstract]

BUSINESS COMBINATION

BUSINESS COMBINATIONS

Acquisition of ClipperCreek, Inc. (“ClipperCreek”)

On December 31, 2021, the Company completed the acquisition of 100% of the shares of ClipperCreek, a privately-held company. ClipperCreek offers electric vehicle (“EV”) charging solutions for residential and commercial customers in the U.S. As part of the purchase price, the Company paid approximately $113.1 million in cash on December 31, 2021. The Company expects this acquisition will allow the Company to enter into the growing EV charging market and provides for cross-selling opportunities.

In addition to the purchase price summarized above, the Company will be obligated to issue up to approximately $40.0 million in shares of common stock of the Company payable in the first quarter of 2023, subject to achievement of certain revenue and operational targets. As the additional payments require continuous employment of certain key employees of ClipperCreek and are subject to other conditions, these payments are being accounted for as post-combination expense and will be recognized ratably over the one year period presuming conditions will be met.

The following table summarizes the preliminary estimated fair values of the assets acquired and liabilities assumed at the acquisition date, which are subject to change within the measurement period as the fair value assessments are finalized (in thousands):


Net tangible assets acquired	$	8,387
Intangible assets	37,800

Goodwill	66,916
Net assets acquired	$	113,103

The excess of the consideration paid over the fair values assigned to the assets acquired and liabilities assumed represents the goodwill resulting from the acquisition. Goodwill is primarily attributable to expected synergies in the Company’s solar offerings and cross-selling opportunities. The entire goodwill amount is expected to be deductible for U.S. federal income tax purposes over 15 years.

Intangible assets consist primarily of trade name and order backlog. Trade name intangible is attributable to marketing goods and services under the ClipperCreek brand and order backlog pertains to purchase orders with customers yet to be fulfilled.

The following table shows the fair value of the separately identifiable intangible assets at the time of acquisition and the period over which each intangible asset will be amortized:


	Preliminary Fair Value		Useful Life
	(In thousands)		(Years)
Order backlog	$	600	Based on actual shipments
Trade name	37,200		5
Total identifiable intangible assets	$	37,800

The consolidated unaudited proforma revenue and net income for the two years presented below, which includes the acquisition of ClipperCreek, assuming the acquisition occurred on January 1, 2020, were (in thousands);


	Years Ended December 31,
		2021		2020
Net revenues		$	1,401,803	$	790,791
Net income		$	145,798	$	139,126

The Company incurred and accrued costs related to this acquisition of $0.5 million that were recorded in general and administrative expenses in the accompanying consolidated statements of operations for the year ended December 31, 2021.

Acquisition of 365 Pronto, Inc. (“365 Pronto”)

On December 13, 2021, the Company completed the acquisition of 100% of the shares of 365 Pronto, a privately-held company. 365 Pronto provides an online platform for clean technology installation and service landscape by matching asset owners with an on-demand qualified workforce in the U.S. As part of the purchase price, the Company paid approximately $69.9 million in cash on December 13, 2021. The Company expects this acquisition will offer installers an online platform to service their operations and maintenance contracts and provides access to a nationwide qualified supplemental labor pool that can perform service calls.

The acquisition has been accounted for as a business combination under the acquisition method, and accordingly, the total purchase price is allocated to the tangible and identifiable intangible assets acquired and liabilities assumed based on their respective fair values on the acquisition date. The results of operations of 365 Pronto have been included in the Company’s consolidated statement of operations from the acquisition date.

In addition to the purchase price above, the Company will be obligated to pay up to approximately $11.0 million in shares of the Company’s common stock in the first half of 2023 subject to achievement of certain revenue, operational and employment targets. As nature of additional payments represents an in-substance service period of certain key employees of 365 Pronto and are subject to other conditions, these payments are being accounted for as post-combination expense and will be recognized ratably over the term of measurement period presuming conditions will be met.


Net tangible assets acquired	$	38
Intangible assets	19,500
Deferred tax liabilities	(2,906)
Goodwill	53,280
Net assets acquired	$	69,912

The excess of the consideration paid over the fair values assigned to the assets acquired and liabilities assumed represents the goodwill resulting from the acquisition. Goodwill is primarily attributable to expected synergies in the Company’s solar offerings and cross-selling opportunities. None of the goodwill is expected to be deductible for U.S. federal income tax purposes.

Intangible assets consist primarily of developed technology and customer relationship intangibles. Intangible assets attributable to developed technology include a combination of unpatented technology, trade secrets, computer software and research processes that represent the foundation for the existing and planned new products to facilitate the generation of new content. Customer relationship intangibles relate to 365 Pronto’s software ability to sell current and future offerings, as well as products built around the current offering, to its existing customers.

The following table shows the fair value of the separately identifiable intangible assets at the time of acquisition and the period over which each intangible asset will be amortized:


	Preliminary Fair Value		Useful Life
	(In thousands)		(Years)
Developed technology	$	18,400	5
Customer relationship	1,100		5
Total identifiable intangible assets	$	19,500

Pro forma financial information has not been presented for the 365 Pronto acquisition as the impact to the Company’s consolidated financial statements was not material.

Acquisition of DIN Engineer Service LLP’s (“DIN”) Solar Design Services Business

On March 31, 2021, the Company completed its acquisition of DIN’s solar design services business. DIN's solar design services business provides outsourced proposal drawings and permit plan sets for residential solar installers in North America and will enhance the Company’s digital transformation effort. As part of the purchase price, the Company paid approximately $24.8 million in cash at closing on March 31, 2021.The Company expects this acquisition will provide installers new services by providing proposal drawing and permit plan sets.

The acquisition has been accounted for as a business combination under the acquisition method; accordingly, the total purchase price is allocated to the tangible and identifiable intangible assets acquired and liabilities assumed based on their respective fair values on the acquisition date. The results of operations of DIN’s solar design services business have been included in the Company’s consolidated statement of operations from the acquisition date.

In addition to the purchase price summarized above, the Company will be obligated to pay up to i) approximately $5.0 million in equal monthly installments over the course of one year following the acquisition date and ii) approximately $5.0 million payable on the one year anniversary following the acquisition date subject to achievement of certain revenue and operational targets. As both additional payments require continuous employment of certain key employees of DIN and are subject to other conditions, these payments are being accounted for as post-combination expense and are recognized ratably over the term of measurement period.

The following table summarizes the fair values of the assets acquired and liabilities assumed at the acquisition date (in thousands):


Net tangible assets acquired	$	1,281
Intangible assets	11,700
Goodwill	11,804
Net assets acquired	$	24,785

The excess of the consideration paid over the fair values assigned to the assets acquired and liabilities assumed represents the goodwill resulting from the acquisition. Goodwill is primarily attributable to expected synergies in the Company’s solar offerings and cross-selling opportunities. None of the goodwill is expected to be deductible for U.S. federal income tax purposes.

Intangible assets consist primarily of customer relationship intangibles. Customer relationship intangibles relate to the ability of the acquired DIN solar design services business to sell current and future offering, as well as products built around the current offering, to its existing customers.

The following table shows the fair value of the separately identifiable intangible assets at the time of acquisition and the period over which each intangible asset will be amortized:

Preliminary Fair Value

Useful Life

(In thousands)

(Years)

Customer relationship

11,700

Pro forma financial information has not been presented for the DIN's solar design services business acquisition as the impact to the Company’s consolidated financial statements was not material.

The Company incurred costs related to this acquisition of $1.9 million that were recorded in general and administrative expenses in the accompanying consolidated statements of operations for the year ended December 31, 2021, respectively.

Acquisition of Sofdesk Inc. (“Sofdesk”)

On January 25, 2021, the Company completed the acquisition of 100% of the shares of Sofdesk, a privately-held company. Sofdesk provides design tools and services software for residential solar installers and roofing companies and will enhance the Company’s digital transformation efforts. The Company expects this acquisition will offer installers design, proposal and permitting services of home energy solutions.

As part of the purchase price, the Company (i) paid approximately $32.0 million in cash on January 25, 2021 and (ii) is liable for up to approximately $3.7 million of contingent consideration payable during the first quarter of 2022, of which the Company recorded a liability of approximately $3.5 million representing the fair value of the contingent consideration.

The contingent consideration is subject to remeasurement at each reporting period until paid. The acquisition date fair value of the purchase price was approximately $35.5 million, which consisted of the following (in thousands):


Cash consideration	$	31,988
Fair value of contingent consideration	3,500
Total	$	35,488

In addition to the purchase price discussed above, the Company will be obligated to pay up to approximately $3.7 million, during the first quarter of 2022, subject to continued employment of key employees of Sofdesk. As this payment is contingent upon the continuous service of the key employees, it is being accounted for as a post-combination expense and is recognized ratably over the term of measurement period.

The acquisition has been accounted for as a business combination under the acquisition method, and accordingly, the total purchase price is allocated to the tangible and identifiable intangible assets acquired and liabilities assumed based on their respective fair values on the acquisition date. The results of operations of Sofdesk have been included in the Company’s consolidated statement of operations from the acquisition date.

The following table summarizes the fair values of the assets acquired and liabilities assumed at the acquisition date, (in thousands):


Net tangible assets acquired	$	1,441
Intangible assets	9,200
Deferred tax asset	457
Goodwill	24,390
Net assets acquired	$	35,488

The excess of the consideration paid over the fair values assigned to the assets acquired and liabilities assumed represents the goodwill resulting from the acquisition. Goodwill is primarily attributable to expected synergies in the Company’s solar offerings and cross-selling opportunities. None of the goodwill is expected to be deductible for U.S. federal income tax purposes.

Intangible assets consist primarily of developed technology, customer relationship intangibles and trade name intangibles. Intangible assets attributable to developed technology include a combination of unpatented technology, trade secrets, computer software and research processes that represent the foundation for the existing and planned new products to facilitate the generation of new content. Customer relationship intangibles relate to Sofdesk’s software ability to sell current and future offerings, as well as products built around the current offering, to its existing customers. Trade name intangibles are attributable to marketing goods and services under the SolargrafTM and RoofgrafTM brands.

The following table shows the fair value of the separately identifiable intangible assets at the time of acquisition and the period over which each intangible asset will be amortized:


	Preliminary Fair Value		Useful Life
	(In thousands)		(Years)
Developed technology	$	6,900	5
Customer relationship	1,800		5
Trade name	500		5
Total identifiable intangible assets	$	9,200

Pro forma financial information has not been presented for the Sofdesk acquisition as the impact to the Company’s consolidated financial statements was not material.

The Company incurred costs related to this acquisition of $2.0 million that were recorded in general and administrative expenses in the accompanying consolidated statements of operations for the year ended December 31, 2021.

GOODWILL AND INTANGIBLE ASSETS

12 Months Ended

Dec. 31, 2021

Goodwill and Intangible Assets Disclosure [Abstract]

GOODWILL AND INTANGIBLE ASSETS

The Company’s goodwill as of December 31, 2021 and December 31, 2020 are as follows:


Goodwill	December 31, 2021		December 31, 2020
	(In thousands)
Goodwill, beginning of period	$	24,783	$	24,783
Goodwill acquired	156,390		—
Currency translation adjustment	81		—
Goodwill, end of period	$	181,254	$	24,783

The Company’s purchased intangible assets as of December 31, 2021 and December 31, 2020 are as follows:


	December 31, 2021								December 31, 2020
	Gross		Additions		Accumulated Amortization		Net		Gross		Additions		Accumulated Amortization		Net
	(In thousands)


Intangible assets:
Other indefinite-lived intangibles	$	286	$	—	$	—	$	286	$	286	$	—	$	—	$	286

Intangible assets with finite lives:

Developed technology	13,100		25,550		(8,958)		29,692		13,100		—		(5,276)		7,824
Customer relationships	26,421		14,600		(11,448)		29,573		23,100		3,321		(5,723)		20,698
Trade names	—		37,700		(93)		37,607		—		—		—		—
Order backlog	—		600		—		600		—		—		—		—
Total purchased intangible assets	$	39,807	$	78,450	$	(20,499)	$	97,758	$	36,486	$	3,321	$	(10,999)	$	28,808

Amortization expense related to finite-lived intangible assets are as follows:


	Years Ended December 31,
		2021		2020
		(In thousands)
Developed technology		$	3,681	$	2,183
Customer relationships		5,726		2,909

Trade names		93		—
Total amortization expense		$	9,500	$	5,092

Amortization of developed technology, customer relationships and trade names is recorded to cost of sales and sales and marketing expense.

The expected future annual amortization expense of intangible assets as of December 31, 2021 is presented below (in thousands):


	December 31, 2021

Fiscal year:
2022	$	22,212
2023	21,856
2024	19,059
2025	17,744
2026	14,185
Thereafter	2,416
Total	$	97,472

CASH EQUIVALENTS AND MARKETABLE SECURITIES

12 Months Ended

Dec. 31, 2021

Cash and Cash Equivalents [Abstract]

CASH EQUIVALENTS AND MARKETABLE SECURITIES

The marketable securities consist of the following (in thousands):


	As of December 31, 2021
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value		Cash and Cash Equivalents		Marketable Securities
Money market funds	$	35,789	$	—	$	—	$	35,789	$	35,789	$	—
Certificate of Deposit	16,001		—		(2)		15,999		6,000		9,999
Commercial paper	215,964		—		(114)		215,850		26,997		188,853
Corporate notes and bonds	199,244		—		(872)		198,372		760		197,612
U.S. Treasuries	14,999		—		(1)		14,998		—		14,998
U.S. Government agency securities	487,743		—		(1,870)		485,873		—		485,873
Total	$	969,740	$	—	$	(2,859)	$	966,881	$	69,546	$	897,335

The following table summarizes the contractual maturities of the Company’s marketable securities as of December 31, 2021 (in thousands):


	Amortized Cost		Fair Value
Due within one year	$	533,237	$	532,689
Due within one to three years	436,503		434,192
Total	$	969,740	$	966,881

All available-for-sale securities have been classified as current, based on management's intent and ability to use the funds in current operations.

ACCRUED LIABILITIES

12 Months Ended

Dec. 31, 2021

Payables and Accruals [Abstract]

ACCRUED LIABILITIES

Accrued liabilities consist of the following:


	December 31, 2021		December 31, 2020
	(In thousands)
Salaries, commissions, incentive compensation and benefits	$	13,062	$	6,634
Customer rebates and sales incentives	79,038		36,622
Freight	20,522		10,300
Operating lease liabilities, current	3,830		4,542
Liability due to supply agreements	14,653		5,500
Contingent consideration	3,710		—
Post combination expense accrual	8,602		—

Other	14,495		12,944
Total accrued liabilities	$	157,912	$	76,542

WARRANTY OBLIGATIONS

12 Months Ended

Dec. 31, 2021

Product Warranties Disclosures [Abstract]

WARRANTY OBLIGATIONS

The Company’s warranty activities were as follows:


	Years Ended December 31,
		2021		2020		2019
		(In thousands)
Warranty obligations, beginning of period		$	45,913	$	37,098	$	31,294
Accruals for warranties issued during period		18,098		7,021		5,244

Changes in estimates		19,414		9,954		8,591
Settlements		(15,073)		(12,811)		(10,881)
Increase due to accretion expense		4,654		3,255		2,326

Other		371		1,396		524
Warranty obligations, end of period		73,377		45,913		37,098
Less: current portion		(19,395)		(11,260)		(10,078)
Non-current		$	53,982	$	34,653	$	27,020

Changes in Estimates

On a quarterly basis, the Company uses the best and most complete underlying information available, following a consistent, systematic and rational methodology to determine its warranty obligations. The Company considers all available evidence to assess the reasonableness of all key assumptions underlying its estimated warranty obligations for each generation of microinverter. The changes in estimates discussed below resulted from consideration of new or additional information becoming available and subsequent developments. Changes in estimates included in the table above were comprised of the following:

2021

In 2021, the Company recorded $19.4 million in warranty expense from changes in estimates, of which $11.6 million relates to continuing analysis of field performance data and diagnostic root-cause failure analysis primarily relating to its prior generation products, and $7.8 million relates to the timing of cost reduction assumptions for replacement products as the Company prioritizes servicing current sales demand and the increase in component costs due to global supply constraints.

2020

In 2020, the Company recorded a $8.8 million increase to warranty expense based on continuing analysis of field performance data and diagnostic root-cause failure analysis primarily relating to its prior generation products. The Company also recorded additional warranty expense of $1.2 million related to unit costs for prior generation microinverter replacement driven by tariffs and labor reimbursement costs expected to be paid to third party installers performing replacement services.

2019

In 2019, the Company recorded a $5.5 million increase to warranty expense related to cost increases primarily driven by increased U.S. tariffs announced during 2019 for its products manufactured in China. The Company also recorded additional warranty expense of $3.1 million based on continuing analysis of field performance data and diagnostic root-cause failure analysis primarily relating to its second and third generation products, partially offset by improved failure rates for its IQ7 series.

FAIR VALUE MEASUREMENTS

12 Months Ended

Dec. 31, 2021

Fair Value Disclosures [Abstract]

FAIR VALUE MEASUREMENTS

The accounting guidance defines fair value as the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. When determining the fair value measurements for assets and liabilities recorded at fair value, the Company considers the principal or most advantageous market in which it would transact and considers assumptions that market participants would use when pricing the asset or liability, such as inherent risk, transfer restrictions, and risk of nonperformance.

The fair value hierarchy requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. An asset’s or liability’s categorization within the fair value hierarchy is based upon the lowest level of input that is significant to the fair value measurement. Three levels of inputs may be used to measure fair value:

•Level 1 - Valuations based on quoted prices in active markets for identical assets or liabilities that the Company is able to access. Since valuations are based on quoted prices that are readily and regularly available in an active market, valuation of such assets or liabilities do not entail a significant degree of judgment.

•Level 2 - Valuations based on one or more quoted prices in markets that are not active or for which all significant inputs are observable, either directly or indirectly.

•Level 3 - Valuations based on inputs that are unobservable and significant to the overall fair value measurement.

The following table presents assets and liabilities measured at fair value on a recurring basis using the above input categories:


	December 31, 2021						December 31, 2020
	(In thousands)
	Level 1		Level 2		Level 3		Level 1		Level 2		Level 3
Assets:
Cash and cash equivalents:
Money market funds	$	35,789	$	—	$	—	$	654,699	$	—	$	—
Certificate of deposit	—		6,000		—		—		—		—
Commercial paper	—		26,997		—		—		—		—
Corporate notes and bonds	—		760		—		—		—		—

Marketable securities:
Certificate of deposit	—		9,999		—		—		—		—
Commercial paper	—		188,853		—		—		—		—
Corporate notes and bonds	—		197,612		—		—		—		—
U.S. Government agencies	—		485,873		—		—		—		—
U.S. Treasuries	—		14,998		—		—		—		—
Other assets
Investments in debt securities	—		—		41,042		—		—		—

Total assets measured at fair value	$	35,789	$	931,092	$	41,042	$	654,699	$	—	$	—

Liabilities:
Accrued liabilities
Contingent consideration	$	—	$	—	$	3,710	$	—	$	—	$	—
Warranty obligations
Current	—		—		14,612		—		—		8,267
Non-current	—		—		36,395		—		—		20,469
Total warranty obligations measured at fair value	—		—		51,007		—		—		28,736
Total liabilities measured at fair value	$	—	$	—	$	54,717	$	—	$	—	$	28,736

Notes due 2028, Notes due 2026 and Notes due 2025

The Company carries the Notes due 2028, Notes due 2026 and Notes due 2025 (as defined below) at face value less unamortized discount and issuance costs on its consolidated balance sheets. The fair value of the Notes due 2028, Notes due 2026 and Notes due 2025 was $594.4 million, $642.3 million and $240.0 million, respectively, as of December 31, 2021 based on the closing trading prices per $100 principal amount as of the last day of trading for the period. The Company considers the fair value of the Notes due 2028, Notes due 2026 and Notes due 2025 to be a Level 2 measurement as they are not actively traded.

Equity investments without readily determinable fair value

In December 2020, the Company invested approximately $5.0 million in a privately-held company without readily determinable market value, which is included in “Other assets” in the consolidated balance sheets. The Company has elected the measurement alternative for equity investments that do not have readily determinable fair values. The Company did not record an impairment charge on its investment during the year ended December 31, 2021, as no events or changes in circumstances were identified which could result as an indicator for impairment. Further, there were no observable price changes in orderly transactions for the identical or a similar investment of the same issuer during the year ended December 31, 2021. Equity investments without readily determinable fair value are classified within Level 3 in the fair value hierarchy because the Company estimates the value based on valuation methods using a combination of observable and unobservable inputs, including valuation ascribed to the issuing company in subsequent financing rounds, volatility in the results of operations of the issuers and rights and obligations of the securities the Company holds.

Investments in debt securities

In January 2021, the Company invested approximately $25.0 million in a privately-held company. The Company concluded the investment qualifies as an investment in a debt security, as it accrues interest and principal plus accrued interest becomes payable back to the Company at certain dates unless it is converted to equity at a pre-determined price. As the investment includes a conversion option, the Company has elected to account for this investment under the fair value option and any change in fair value of the investment is recognized in “Other income (expense), net” in the Company’s consolidated statement of operations for that period. Further, the Company has concluded that the Company’s investment in a debt security is considered to be a Level 3 measurement due to the use of significant unobservable inputs in the valuation model. The fair value was determined using discounted cash flow methodology and assumptions include implied yield and change in estimated term of investment being held-to-maturity.

In June 2021, the Company invested approximately $20.0 million in secured convertible promissory notes issued by a privately-held company. The investment qualifies as an investment in a debt security and will accrete interest and principal plus accrued interest becomes payable at certain dates unless it is converted to equity at a pre-determined price. As the investment includes a conversion option, the Company has elected to account for this investment under the fair value option and any change in fair value of the investment is recognized in “Other income (expense), net” in the Company’s consolidated statement of operations for that period. During the fourth quarter of 2021, the Company received $26.6 million in cash in full settlement of $20.0 million principal amount of promissory notes and $6.6 million towards accrued and unpaid interest and change in control premium per contract terms. The $6.6 million was recognized as other income in “Other (expense) income, net” in the Company’s consolidated statement of operations.

In September 2021, the Company invested approximately $13.0 million in secured convertible promissory notes issued by the stockholders of a privately-held company. The investment qualifies as an investment in a debt security and will accrete interest and principal plus accrued interest that becomes payable at certain dates unless it is converted to equity at a pre-determined price. As the investment includes a conversion option, the Company has elected to account for this investment under the fair value option and any change in fair value of the investment is recognized in “Other income (expense), net” in the Company’s consolidated statement of operations for that period. Further, the Company has concluded that the Company’s investment in a debt security is considered a Level 3 measurement due to the use of significant unobservable inputs in the valuation model. Principal plus accrued interest receivable of the investment approximates the fair value.

Investment in debt securities are recorded in “Other Assets” on the accompanying consolidated balance sheet as of December 31, 2021. The changes in the balance in investments in debt securities during the period are as follows:


	Year Ended December 31,
		2021
		(In thousands)
Balance at beginning of period		$	—
Investment		58,000
Fair value adjustments included in other (expense) income, net		9,611
Settlement		(26,569)
Balance at end of period		$	41,042

Contingent consideration

The estimated fair value of the contingent consideration incurred in connection with the Company’s acquisition of Sofdesk is considered a Level 3 measurement due to the use of significant unobservable inputs. These unobservable inputs include probability assessment of expected future customer count over the period in which the obligation is expected to be settled. The value was determined using a discounted risk-neutral expected (probability-weighted) cash flow methodology. The resulting expected contingent consideration payment is discounted back to present value using the Company’s cost of debt. The fair value of contingent consideration arrangement is reassessed quarterly based on assumptions used in the Company’s latest projections and input provided by management. Any change in the fair value estimate, which could include accretion of interest expense due to passage of time as well as any changes in the inputs to the model, is recorded in the Company’s consolidated statement of operations for that period.

The following table reflects the activity for the Company’s contingent consideration liabilities measured at fair value using Level 3 inputs for the year ended December 31, 2021:


	Year Ended December 31,
		2021
		(In thousands)
Balance at beginning of period		$	—
Addition		3,500
Fair value adjustments included in other income (expense), net		210
Balance at end of period		$	3,710

Warranty obligations.

Fair Value Option for Warranty Obligations Related to Microinverters and Other Products Sold Since January 1, 2014

The Company estimates the fair value of warranty obligations by calculating the warranty obligations in the same manner as for sales prior to January 1, 2014 and applying an expected present value technique to that result. The expected present value technique, an income approach, converts future amounts into a single current discounted amount. In addition to the key estimates of failure rates, claim rates and replacement costs, the Company used certain Level 3 inputs which are unobservable and significant to the overall fair value measurement. Such additional assumptions included a discount rate based on the Company’s credit-adjusted risk-free rate and compensation comprised of a profit element and risk premium required of a market participant to assume the obligation.

The following table provides information regarding changes in nonfinancial liabilities related to the Company’s warranty obligations measured at fair value on a recurring basis using significant unobservable inputs (Level 3) for the periods indicated.


	Years Ended December 31,
		2021		2020
		(In thousands)
Balance at beginning of period		$	28,736	$	19,806
Accruals for warranties issued during period		18,098		7,021
Changes in estimates		10,844		5,039
Settlements		(11,248)		(7,781)
Increase due to accretion expense		4,654		3,255
Other		(77)		1,396
Balance at end of period		$	51,007	$	28,736

Quantitative and Qualitative Information about Level 3 Fair Value Measurements

As of December 31, 2021 and December 31, 2020, the significant unobservable inputs used in the fair value measurement of the Company’s liabilities designated as Level 3 are as follows:

Percent Used

(Weighted Average)

Item Measured at Fair Value

Valuation Technique

Description of Significant Unobservable Input

December 31,
2021

December 31,
2020

Warranty obligations for microinverters sold since January 1, 2014

Discounted cash flows

Profit element and risk premium

15%

Credit-adjusted risk-free rate

12%

13%

Sensitivity of Level 3 Inputs - Warranty Obligations

Each of the significant unobservable inputs is independent of the other. The profit element and risk premium are estimated based on requirements of a third-party participant willing to assume the Company’s warranty obligations. The credit‑adjusted risk‑free rate (“discount rate”) is determined by reference to the Company’s own credit standing at the fair value measurement date. Increasing the profit element and risk premium input by 100 basis points would result in no material change to the liability. Decreasing the profit element and risk premium by 100 basis points would result in a $0.9 million reduction of the liability. Increasing the discount rate by 100 basis points would result in a $2.9 million reduction of the liability. Decreasing the discount rate by 100 basis points would result in a $2.3 million increase to the liability.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

RESTRUCTURING

12 Months Ended

Dec. 31, 2021

Restructuring and Related Activities [Abstract]

RESTRUCTURING

Restructuring expense consist of the following:


	Years Ended December 31,
		2021		2020		2019
		(In thousands)
Redundancy and employee severance and benefit arrangements		$	—	$	—	$	1,575
Asset impairments		—		—		1,124

Lease loss reserves (benefit)		—		—		(100)

Total restructuring charges		$	—	$	—	$	2,599

2018 Plan

In the third quarter of 2018, the Company began implementing restructuring actions (the “2018 Plan”) to lower its operating expenses. The restructuring actions include reorganization of the Company’s global workforce, elimination of certain non-core projects and consolidation of facilities. The Company completed its restructuring activities under the 2018 Plan in 2019.

The following table presents the details of the Company’s restructuring charges under the 2018 Plan for the period indicated:


	Years Ended December 31,
		2021		2020		2019
		(In thousands)
Redundancy and employee severance and benefit arrangements		$	—	$	—	$	1,575
Asset impairments		—		—		1,124

Lease loss reserves (benefit)		—		—		(100)

Total restructuring charges		$	—	$	—	$	2,599

DEBT

12 Months Ended

Dec. 31, 2021

Debt Disclosure [Abstract]

DEBT

The following table provides information regarding the Company’s debt.


	December 31, 2021		December 31, 2020
	(In thousands)
Convertible notes
Notes due 2028	$	575,000	$	—
Less: unamortized discount and issuance costs	(149,411)		—
Carrying amount of Notes due 2028	425,589		—

Notes due 2026	632,500		—
Less: unamortized discount and issuance costs	(111,433)		—
Carrying amount of Notes due 2026	521,067		—

Notes due 2025	102,175		320,000
Less: unamortized discount and issuance costs	(16,123)		(64,979)
Carrying amount of Notes due 2025	86,052		255,021

Notes due 2024	—		88,140
Less: unamortized discount and issuance costs	—		(19,119)
Carrying amount of Notes due 2024	—		69,021

Notes due 2023	5,000		5,000
Less: unamortized issuance costs	(62)		(102)
Carrying amount of Notes due 2023	4,938		4,898

Sale of long-term financing receivable recorded as debt	—		1,925


Total carrying amount of debt	1,037,646		330,865

Less: current portion of convertible notes and long-term financing receivable recorded as debt	(86,052)		(325,967)
Debt, non-current	$	951,594	$	4,898

Convertible Senior Notes due 2028

On March 1, 2021, the Company issued $575 million aggregate principal amount of 0.0% convertible senior notes due 2028 (the “Notes due 2028”). The Notes due 2028 will not bear regular interest, and the principal amount of the Notes due 2028 will not accrete. The Notes due 2028 are general unsecured obligations and are governed by an indenture between the Company and U.S. Bank National Association, as trustee. The Notes due 2028 will mature on March 1, 2028, unless earlier repurchased by the Company or converted at the option of the holders. The Company received approximately $566.4 million in net proceeds, after deducting the initial purchasers’ discount, from the issuance of the Notes due 2028.

The initial conversion rate for the Notes due 2028 is 3.5104 shares of common stock per $1,000 principal amount of the Notes due 2028 (which represents an initial conversion price of approximately $284.87 per share). The conversion rate for the Notes due 2028 will be subject to adjustment upon the occurrence of certain specified events but will not be adjusted for any accrued and unpaid special interest, if any. In addition, if a make-whole fundamental change or a redemption with respect to the Notes due 2028 occurs prior to the maturity date, under certain circumstances as specified in the relevant indenture, the Company will increase the conversion rate for the Notes due 2028 by a number of additional shares of the Company’s common stock for a holder that elects to convert its notes in connection with such make-whole fundamental change or redemption. Upon conversion, the Company will settle conversions of the Notes due 2028 through payment or delivery, as the case may be, of cash, shares of its common stock or a combination of cash and shares of its common stock, at the Company’s election.

The Company may not redeem the Notes due 2028 prior to September 6, 2024. The Company may redeem for cash all or any portion of the Notes due 2028, at the Company’s election, on or after September 6, 2024, if the last reported sale price of the Company’s common stock has been greater than or equal to 130% of the conversion price then in effect for the Notes due 2028 (i.e. $370.33, which is 130% of the current conversion price for the Notes due 2028) for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period ending on, and including, the trading day immediately preceding the date on which the Company provides notice of redemption. The redemption price will equal 100% of the principal amount of the Notes due 2028 to be redeemed, plus accrued and unpaid special interest, if any to, but excluding, the relevant redemption date. No sinking fund is provided for the Notes due 2028.

The Notes due 2028 may be converted on any day prior to the close of business on the business day immediately preceding September 1, 2027, in multiples of $1,000 principal amount, at the option of the holder only under any of the following circumstances: (1) during any calendar quarter commencing after the calendar quarter ending on June 30, 2021 (and only during such calendar quarter), if the last reported sale price of the Company’s common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price for the Notes due 2028 (i.e., $370.33 which is 130% of the current conversion price for the Notes due 2028) on each applicable trading day; (2) during the five business day period after any five consecutive trading day period (the “Measurement Period”) in which the “trading price” (as defined in the relevant indenture) per $1,000 principal amount of notes for each trading day of the Measurement Period was less than 98% of the product of the last reported sale price of the Company’s common stock and the conversion rate for the Notes due 2028 on each such trading day; (3) if the Company calls any or all of the Notes due 2028 for redemption, at any time prior to the close of business on the scheduled trading day immediately preceding the redemption date; or (4) upon the occurrence of specified corporate events. On and after September 1, 2027 until the close of business on the second scheduled trading day immediately preceding the maturity date of March 1, 2028, holders of the Notes due 2028 may convert their notes at any time, regardless of the foregoing circumstances. Upon the occurrence of a fundamental change (as defined in the relevant indenture), holders may require the Company to repurchase all or a portion of their Notes due 2028 for cash at a price equal to 100% of the principal amount of the notes to be repurchased plus any accrued and unpaid special interest, if any, to, but excluding, the fundamental change repurchase date.

In accounting for the issuance of the Notes due 2028 on March 1, 2021, the Company separated the Notes due 2028 into liability and equity components. The carrying amount of the liability component of approximately $415.0 million was calculated by using a discount rate of 4.77%, which was the Company’s borrowing rate on the date of the issuance of the Notes due 2028 for a similar debt instrument without the conversion feature. The carrying amount of the equity component of approximately $160.0 million, representing the

conversion option, was determined by deducting the fair value of the liability component from the par value of the Notes due 2028. The equity component of the Notes due 2028 is included in additional paid-in capital in the consolidated balance sheet and is not remeasured as long as it continues to meet the conditions for equity classification. The difference between the principal amount of the Notes due 2028 and the liability component (the “debt discount”) is amortized to interest expense using the effective interest method over the term of the Notes due 2028.

The Company separated the Notes due 2028 into liability and equity components which resulted in a tax basis difference associated with the liability component that represents a temporary difference. The Company recognized the deferred taxes of $40.1 million for the tax effect of that temporary difference as an adjustment to the equity component included in additional paid-in capital in the consolidated balance sheet.

Debt issuance costs for the issuance of the Notes due 2028 were approximately $9.1 million, consisting of initial purchasers' discount and other issuance costs. In accounting for the transaction costs, the Company allocated the total amount incurred to the liability and equity components using the same proportions as the proceeds from the Notes due 2028. Transaction costs attributable to the liability component were approximately $6.6 million, which were recorded as debt issuance cost (presented as contra debt in the consolidated balance sheet) and are being amortized to interest expense over the term of the Notes due 2028. The transaction costs attributable to the equity component were approximately $2.5 million and were netted with the equity component in stockholders’ equity. As of December 31, 2021, the unamortized deferred issuance cost for the Notes due 2028 was $5.8 million on the consolidated balance sheet.

The following table presents the total amount of interest cost recognized in the statement of operations relating to the Notes due 2028:


	Year Ended December 31, 2021
		(In thousands)

Amortization of debt discount		$	16,401
Amortization of debt issuance costs		785
Total interest cost recognized		$	17,186

The effective interest rate on the liability component on the Notes due 2028 was 4.77% for the year ended December 31, 2021, which remains unchanged from the date of issuance. The remaining unamortized debt discount was $143.6 million as of December 31, 2021 and will be amortized over approximately 6.2 years from December 31, 2021.

Notes due 2028 Hedge and Warrant Transactions

In connection with the offering of the Notes due 2028, the Company entered into privately-negotiated convertible note hedge transactions (“Notes due 2028 Hedge”) pursuant to which the Company has the option to purchase a total of approximately 2.0 million shares of its common stock (subject to anti-dilution adjustments), which is the same number of shares initially issuable upon conversion of the Notes due 2028, at a price of $284.87 per share, which is the initial conversion price of the Notes due 2028. The total cost of the convertible note hedge transactions was approximately $161.6 million. The convertible note hedge transactions are expected generally to reduce potential dilution to the Company’s common stock upon any conversion of the Notes due 2028 and/or offset any cash payments the Company is required to make in excess of the principal amount of converted notes, as the case may be.

Additionally, the Company separately entered into privately-negotiated warrant transactions (the “2028 Warrants”) whereby the Company sold warrants to acquire approximately 2.0 million shares of the Company’s common stock (subject to anti-dilution adjustments) at an initial strike price of $397.91 per share. The Company received aggregate proceeds of approximately $123.4 million from the sale of the 2028 Warrants. If the market value per share of the Company’s common stock, as measured under the 2028 Warrants, exceeds the strike price of the 2028 Warrants, the 2028 Warrants will have a dilutive effect on the Company’s earnings per share, unless the Company elects, subject to certain conditions, to settle the 2028 Warrants in cash. Taken together, the purchase of the Notes due 2028 Hedge and the sale of the 2028 Warrants are intended to reduce potential dilution from the

conversion of the Notes due 2028 and to effectively increase the overall conversion price from $284.87 to $397.91 per share. The 2028 Warrants are only exercisable on the applicable expiration dates in accordance with the Notes due 2028 Hedge. Subject to the other terms of the Warrants, the first expiration date applicable to the Notes due 2028 Hedge is June 1, 2028, and the final expiration date applicable to the Notes due 2028 Hedge is July 27, 2028.

Given that the transactions meet certain accounting criteria, the Notes due 2028 Hedge and the 2028 Warrants transactions are recorded in stockholders’ equity, and they are not accounted for as derivatives and are not remeasured each reporting period.

Convertible Senior Notes due 2026

On March 1, 2021, the Company issued $575.0 million aggregate principal amount of 0.0% convertible senior notes due 2026 (the “Notes due 2026”). In addition, on March 12, 2021, the Company issued an additional $57.5 million aggregate principal amount of the Notes due 2026 pursuant to the initial purchasers’ full exercise of the over-allotment option for additional Notes due 2026. The Notes due 2026 will not bear regular interest, and the principal amount of the Notes due 2026 will not accrete. The Notes due 2026 are general unsecured obligations and are governed by an indenture between the Company and U.S. Bank National Association, as trustee. The Notes due 2026 will mature on March 1, 2026, unless earlier repurchased by the Company or converted at the option of the holders. The Company received approximately $623.0 million in net proceeds, after deducting the initial purchasers’ discount, from the issuance of the Notes due 2026.

The initial conversion rate for the Notes due 2026 is 3.2523 shares of common stock per $1,000 principal amount of the Notes due 2026 (which represents an initial conversion price of approximately $307.47 per share). The conversion rate for the Notes due 2026 will be subject to adjustment upon the occurrence of certain specified events but will not be adjusted for accrued and unpaid interest. In addition, if a make-whole fundamental change or a redemption with respect to the Notes due 2026 occurs prior to the maturity date, under certain circumstances as specified in the relevant indenture, the Company will increase the conversion rate for the Notes due 2026 by a number of additional shares of the Company’s common stock for a holder that elects to convert its notes in connection with such make-whole fundamental change or redemption. Upon conversion, the Company will settle conversions of Notes due 2026 through payment or delivery, as the case may be, of cash, shares of its common stock or a combination of cash and shares of its common stock, at the Company’s election.

The Company may not redeem the Notes due 2026 prior to the September 6, 2023. The Company may redeem for cash all or any portion of the Notes due 2026, at the Company’s election, on or after September 6, 2023, if the last reported sale price of the Company’s common stock has been greater than or equal to 130% of the conversion price then in effect for the Notes due 2026 (i.e., $399.71, which is 130% of the current conversion price for the Notes due 2026) for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading day period ending on, and including, the trading day immediately preceding the date on which the Company provides notice of redemption. The redemption price will equal 100% of the principal amount of the Notes due 2026 to be redeemed, plus accrued and unpaid special interest, if any, to, but excluding, the relevant redemption date for the Notes due 2026. The redemption price will be increased as described in the relevant indentures by a number of additional shares of the Company in connection with such optional redemption by the Company. No sinking fund is provided for the Notes due 2026.

The Notes due 2026 may be converted on any day prior to the close of business on the business day immediately preceding September 1, 2025, in multiples of $1,000 principal amount, at the option of the holder only under any of the following circumstances: (1) during any calendar quarter commencing after the calendar quarter ending on June 30, 2021 (and only during such calendar quarter), if the last reported sale price of the Company’s common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price of the Notes due 2026 (i.e., $399.71, which is 130% of the current conversion price for the Notes due 2026) on each applicable trading day; (2) during the five business day period after any five consecutive trading day period (the “measurement period”) in which the “trading price” (as defined in the relevant indenture) per $1,000 principal amount of notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price of the Company’s common stock and the conversion rate for Notes due 2026 on each such trading day; (3) if the Company calls any or all of the Notes due 2026 for redemption, at any time prior to the close of business on the scheduled trading day immediately preceding the redemption date; or

(4) upon the occurrence of specified corporate events. On and after September 1, 2025 until the close of business on the second scheduled trading day immediately preceding the maturity date of March 1, 2026, holders of the Notes due 2026 may convert their notes at any time, regardless of the foregoing circumstances. Upon the occurrence of a fundamental change (as defined in the relevant indenture), holders may require the Company to repurchase all or a portion of their Notes due 2026 for cash at a price equal to 100% of the principal amount of the notes to be repurchased plus any accrued and unpaid special interest, if any, to, but excluding, the fundamental change repurchase date.

In accounting for the issuance of the Notes due 2026 on March 1, 2021, the Company separated the Notes due 2026 into liability and equity components. The carrying amount of the liability component of approximately $509.0 million was calculated by using a discount rate of 4.44%, which was the Company’s borrowing rate on the date of the issuance of the Notes due 2026 for a similar debt instrument without the conversion feature. The carrying amount of the equity component of approximately $123.5 million, representing the conversion option, was determined by deducting the fair value of the liability component from the par value of the Notes due 2026. The equity component of the Notes due 2026 is included in additional paid-in capital in the consolidated balance sheet and is not remeasured as long as it continues to meet the conditions for equity classification. The difference between the principal amount of the Notes due 2026 and the liability component (the “debt discount”) is amortized to interest expense using the effective interest method over the term of the Notes due 2026.

The Company separated the Notes due 2026 into liability and equity components which resulted in a tax basis difference associated with the liability component that represents a temporary difference. The Company recognized the deferred taxes of $31.0 million for the tax effect of that temporary difference as an adjustment to the equity component included in additional paid-in capital in the consolidated balance sheet.

Debt issuance costs for the issuance of the Notes due 2026 were approximately $10.0 million, consisting of initial purchasers' discount and other issuance costs. In accounting for the transaction costs, the Company allocated the total amount incurred to the liability and equity components using the same proportions as the proceeds from the Notes due 2026. Transaction costs attributable to the liability component were approximately $8.0 million, which were recorded as debt issuance cost (presented as contra debt in the consolidated balance sheet) and are being amortized to interest expense over the term of the Notes due 2026. The transaction costs attributable to the equity component were approximately $2.0 million and were netted with the equity component in stockholders’ equity. As of December 31, 2021, the unamortized deferred issuance cost for the Notes due 2026 was $6.7 million on the consolidated balance sheet.

The following table presents the total amount of interest cost recognized in the statement of operations relating to the Notes due 2026:


	Year Ended December 31, 2021
		(In thousands)

Amortization of debt discount		$	18,735
Amortization of debt issuance costs		1,347
Total interest cost recognized		$	20,082

The effective interest rate on the liability component of Notes due 2026 was 4.44% for the year ended December 31, 2021, which remains unchanged from the date of issuance. The remaining unamortized debt discount was $104.8 million as of December 31, 2021, and will be amortized over approximately 4.2 years from December 31, 2021.

Notes due 2026 Hedge and Warrant Transactions

In connection with the offering of the Notes due 2026 (including in connection with the issuance of additional Notes due 2026 upon the initial purchasers’ exercise of their over-allotment option), the Company entered into privately-negotiated convertible note hedge transactions (the “Notes due 2026 Hedge”) pursuant to which the Company has the option to purchase a total of approximately 2.1 million shares of its common stock (subject to anti-dilution adjustments), which is the same number of shares initially issuable upon conversion of the Notes due 2026, at a price of $307.47 per share, which is the initial conversion price of the Notes due 2026. The total cost of the Notes due 2026 Hedge was approximately $124.6 million. The Notes due 2026 Hedge are expected generally to reduce potential dilution to the Company’s common stock upon any conversion of the Notes due 2026 and/or offset any cash payments the Company is required to make in excess of the principal amount of converted notes, as the case may be.

Additionally, the Company separately entered into privately-negotiated warrant transactions, including in connection with the issuance of additional Notes due 2026 upon the initial purchasers’ exercise of their over-allotment option (the “2026 Warrants”), whereby the Company sold warrants to acquire approximately 2.1 million shares of the Company’s common stock (subject to anti-dilution adjustments) at an initial strike price of $397.91 per share. The Company received aggregate proceeds of approximately $97.4 million from the sale of the 2026 Warrants. If the market value per share of the Company’s common stock, as measured under the 2026 Warrants, exceeds the strike price of the Warrants, the 2026 Warrants will have a dilutive effect on the Company’s earnings per share, unless the Company elects, subject to certain conditions, to settle the 2026 Warrants in cash. Taken together, the purchase of the Notes due 2026 Hedge and the sale of the 2026 Warrants are intended to reduce potential dilution from the conversion of the Notes due 2026 and to effectively increase the overall conversion price from $307.47 to $397.91 per share. The 2026 Warrants are only exercisable on the applicable expiration dates in accordance with the 2026 Warrants. Subject to the other terms of the 2026 Warrants, the first expiration date applicable to the Warrants is June 1, 2026, and the final expiration date applicable to the 2026 Warrants is July 27, 2026.

Given that the transactions meet certain accounting criteria, the Notes due 2026 hedge and the warrants transactions are recorded in stockholders’ equity, and they are not accounted for as derivatives and are not remeasured each reporting period.

Convertible Senior Notes due 2025

On March 9, 2020, the Company issued $320.0 million aggregate principal amount of the Notes due 2025. The Notes due 2025 are general unsecured obligations and bear interest at an annual rate of 0.25% per year, payable semi-annually on March 1 and September 1 of each year, beginning September 1, 2020. The Notes due 2025 are governed by an indenture between the Company and U.S. Bank National Association, as trustee. The Notes due 2025 will mature on March 1, 2025, unless earlier repurchased by the Company or converted at the option of the holders. The Company may not redeem the notes prior to the maturity date, and no sinking fund is provided for the notes. The Notes due 2025 may be converted, under certain circumstances as described below, based on an initial conversion rate of 12.2637 shares of common stock per $1,000 principal amount (which represents an initial conversion price of $81.54 per share). The conversion rate for the Notes due 2025 will be subject to adjustment upon the occurrence of certain specified events but will not be adjusted for accrued and unpaid interest. In addition, upon the occurrence of a make-whole fundamental change (as defined in the relevant indenture), the Company will, in certain circumstances, increase the conversion rate by a number of additional shares for a holder that elects to convert its notes in connection with such make-whole fundamental change. The Company received approximately $313.0 million in net proceeds, after deducting the initial purchasers’ discount, from the issuance of the Notes due 2025.

The Notes due 2025 may be converted prior to the close of business on the business day immediately preceding September 1, 2024, in multiples of $1,000 principal amount, at the option of the holder only under the following circumstances: (1) during any calendar quarter commencing after the calendar quarter ending on June 30, 2020 (and only during such calendar quarter), if the last reported sale price of the Company’s common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price on each applicable trading day; (2) during the five business day period after any five consecutive trading day period (the “measurement period”) in which the “trading price” (as defined in the relevant indenture) per

$1,000 principal amount of notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price of the Company’s common stock and the conversion rate on each such trading day; or (3) upon the occurrence of specified corporate events. On and after September 1, 2024 until the close of business on the second scheduled trading day immediately preceding the maturity date of March 1, 2025, holders may convert their notes at any time, regardless of the foregoing circumstances. Upon the occurrence of a fundamental change (as defined in the relevant indenture), holders may require the Company to repurchase all or a portion of their Notes due 2025 for cash at a price equal to 100% of the principal amount of the notes to be repurchased plus any accrued and unpaid interest to, but excluding, the fundamental change repurchase date.

As of December 31, 2021 and 2020, the sale price of the Company’s common stock was greater than or equal to $106.00 (130% of the notes conversion price) for at least 20 trading days (whether consecutive or not) during a period of 30 consecutive trading days preceding the quarter-ended December 31, 2021 and 2020. As a result, as of January 1, 2021, the Notes due 2025 are convertible at the holders’ option through March 31, 2022. Accordingly, the Company classified the net carrying amount of the Notes due 2025 of $86.1 million and $255.0 million as Debt, current on the consolidated balance sheet as of December 31, 2021 and 2020, respectively. From January 1, 2022 through the date this Annual Report on Form 10-K is available to be issued, the Company has not received any requests for conversion of the Notes due 2025.

For the period from March 9, 2020, the issuance date, through May 19, 2020, the number of authorized and unissued shares of the Company’s common stock that are not reserved for other purposes was less than the maximum number of underlying shares that would be required to settle the Notes due 2025 into equity. Accordingly, unless and until the Company had a number of authorized shares that were not issued or reserved for any other purpose that equaled or exceeded the maximum number of underlying shares (the “Share Reservation Condition”), the Company would have been required to pay to the converting holder in respect of each $1,000 principal amount of notes being converted solely in cash in an amount equal to the sum of the daily conversion values for each of the 20 consecutive trading days during the related observation period. However, following satisfaction of the Share Reservation Condition, the Company could settle conversions of notes through payment or delivery, as the case may be, of cash, shares of the Company’s common stock or a combination of cash and shares of its common stock, at the Company’s election. As further discussed below, the Company satisfied the Share Reservation Condition during May 2020.

In accounting for the issuance of the Notes due 2025, on March 9, 2020, the conversion option of the Notes due 2025 was deemed an embedded derivative requiring bifurcation from the Notes due 2025 (the “host contract”) and separate accounting as an embedded derivative liability, as a result of the Company not having the necessary number of authorized but unissued shares of its common stock available to settle the conversion option of the Notes due 2025 in shares. The proceeds from the Notes due 2025 were first allocated to the embedded derivative liability and the remaining proceeds were then allocated to the host contract. On March 9, 2020, the carrying amount of the embedded derivative liability of $68.7 million representing the conversion option was determined using the Binomial Lattice model and the remaining $251.3 million was allocated to the host contract. The difference between the principal amount of the Notes due 2025 and the fair value of the host contract (the “debt discount”) is amortized to interest expense using the effective interest method over the term of the Notes due 2025.

On May 20, 2020, at the Company’s annual meeting of stockholders, the stockholders approved an amendment to the Amended and Restated Certificate of Incorporation to increase the number of authorized shares of the Company’s common stock, par value $0.00001 per share, from 150,000,000 shares to 200,000,000 shares (the “Amendment”). The Amendment became effective upon filing with the Secretary of State of Delaware on May 20, 2020. As a result, the Company satisfied the Share Reservation Condition. The Company may now settle the Notes due 2025 and warrants issued in conjunction with the Notes due 2025 through payment or delivery, as the case may be, of cash, shares of its common stock or a combination of cash and shares of its common stock, at the Company’s election. Accordingly, on May 20, 2020, the embedded derivative liability was remeasured at a fair value of $116.3 million and was then reclassified to additional paid-in-capital in the consolidated balance sheet in the second quarter of 2020 and is no longer remeasured as long as it continues to meet the conditions for equity classification. The Company recorded the change in the fair value of the embedded derivative in other expense, net in the consolidated statement of operations during the year ended December 31, 2020.

The Company separated the Notes due 2025 into liability and equity components which resulted in a tax basis difference associated with the liability component that represents a temporary difference. The Company recognized the deferred taxes of $0.2 million for the tax effect of that temporary difference as an adjustment to the equity component included in additional paid-in capital in the consolidated balance sheet.

Debt issuance costs for the issuance of the Notes due 2025 were approximately $7.6 million, consisting of initial purchasers' discount and other issuance costs. In accounting for the transaction costs, the Company allocated the total amount incurred to the Notes due 2025 host contract. Transaction costs were recorded as debt issuance cost (presented as contra debt in the consolidated balance sheet) and are being amortized to interest expense over the term of the Notes due 2025.

Partial repurchase of Notes due 2025

Concurrently with the offering of the Notes due 2026 and Notes due 2028, the Company entered into separately- and privately-negotiated transactions to repurchase approximately $217.7 million aggregate principal amount of the Notes due 2025. The Company paid $217.7 million in cash and issued approximately 1.67 million shares of its common stock to the holders of the repurchased notes with an aggregate fair value of $302.7 million, representing the conversion value in excess of the principal amount of the Notes due 2025, which were fully offset by shares received from the Company’s settlement of the associated note hedging arrangements discussed below. The total amount of $217.7 million paid to partially settle the repurchases of the Notes due 2025 was allocated between the liability and equity components of the amount extinguished by determining the fair value of the liability component immediately prior to the note repurchases and allocating that portion of the conversion price to the liability component in the amount of $184.5 million. The residual of the conversion price of $4.3 million of the repurchased Notes due 2025, net of inducement loss of $37.5 million for additional shares issued, was allocated to the equity component of the repurchased Notes due 2025 as an increase of additional paid-in capital. The fair value of the note settlement for such repurchases was calculated using a discount rate of 4.35%, representing an estimate of the Company's borrowing rate at the date of repurchase with a remaining expected life of approximately 4.1 years. As part of the settlement of the repurchase of the Notes due 2025, the Company wrote-off the $38.5 million unamortized debt discount and $4.1 million debt issuance cost apportioned to the principal amount of Notes due 2025 repurchased. The Company recorded a loss on partial settlement of the repurchased Notes due 2025 of $9.4 million in Other income (expense), net in the year ended December 31, 2021, representing the difference between the consideration attributed to the liability component and the sum of the net carrying amount of the liability component and unamortized debt issuance costs. Further, the Company also recorded loss on inducement of $37.5 million in Other income (expense), net in the year ended December 31, 2021, representing the difference between the fair value of the shares that would have been issued under the original conversion terms with respect to the repurchased Notes due 2025.

During the second quarter of 2021, $0.1 million in aggregate principal amount of the Notes due 2025 were converted, and the principal amount of the converted Notes due 2025 was repaid in cash. In connection with such conversions during the second quarter of 2021, the Company also issued 485 shares of its common stock to the holders of the converted Notes due 2025, with an aggregate fair value of $0.1 million, representing the conversion value in excess of the principal amount of the Notes due 2025, which were fully offset by shares received from the settlements of the associated note hedging arrangements. Following the repurchase transactions summarized above, as of December 31, 2021, $102.2 million aggregate principal amount of the Notes due 2025 remained outstanding.

The following table presents the total amount of interest cost recognized relating to the Notes due 2025:



	Years Ended December 31,
		2021		2020
		(In thousands)
Contractual interest expense		$	342	$	649
Amortization of debt discount		5,529		10,072
Amortization of debt issuance costs		661		1,229
Total interest cost recognized		$	6,532	$	11,950

The derived effective interest rate on the Notes due 2025 host contract was determined to be 5.18%, which remains unchanged from the date of issuance. The remaining unamortized debt discount was $14.6 million and $58.6 million as of December 31, 2021 and 2020, respectively, and will be amortized over approximately 3.2 years from December 31, 2021.

Notes due 2025 Hedge and Warrant Transactions

In connection with the offering of the Notes due 2025, the Company entered into privately-negotiated convertible note hedge transactions (the “Notes due 2025 Hedge”) pursuant to which the Company has the option to purchase a total of approximately 3.9 million shares of its common stock (subject to anti-dilution adjustments), which is the same number of shares initially issuable upon conversion of the notes, at a price of $81.54 per share, which is the initial conversion price of the Notes due 2025. The total cost of the convertible note hedge transactions was approximately $89.1 million. The convertible note hedge transactions are expected generally to reduce potential dilution to the Company’s common stock upon any conversion of the Notes due 2025 and/or offset any cash payments the Company is required to make in excess of the principal amount of converted notes, as the case may be.

Additionally, the Company separately entered into privately-negotiated warrant transactions in connection with the offering of the Notes due 2025 (the “2025 Warrants”) whereby the Company sold warrants to acquire approximately 3.9 million shares of the Company’s common stock (subject to anti-dilution adjustments) at an initial strike price of $106.94 per share. The Company received aggregate proceeds of approximately $71.6 million from the sale of the 2025 Warrants. If the market value per share of the Company’s common stock, as measured under the 2025 Warrants, exceeds the strike price of the 2025 Warrants, the 2025 Warrants will have a dilutive effect on the Company’s earnings per share, unless the Company elects, subject to certain conditions, to settle the 2025 Warrants in cash. Taken together, the purchase of the convertible note hedges in connection with the Notes due 2025 Hedge and the sale of the 2025 Warrants are intended to reduce potential dilution from the conversion of the Notes due 2025 and to effectively increase the overall conversion price from $81.54 to $106.94 per share. The 2025 Warrants are only exercisable on the applicable expiration dates in accordance with the agreements relating to each of the 2025 Warrants. Subject to the other terms of the 2025 Warrants, the first expiration date applicable to the 2025 Warrants is June 1, 2025, and the final expiration date applicable to the 2025 Warrants is September 23, 2025.

During the first quarter of 2021, in connection with the repurchase of $217.7 million aggregate principal amount of the Notes due 2025 summarized above, the Company entered into partial unwind agreements with respect to certain of the Notes due 2025 Hedge and the 2025 Warrants. In connection with these unwind transactions, the Company received shares of the Company’s common stock as a termination payment for the portion of the Notes due 2025 Hedge that were unwound, and the Company issued shares of its common stock as a termination payment for the portion of the 2025 Warrants that were unwound. As a result of the unwind agreements for the Notes due 2025 Hedge and the 2025 Warrants, the Company received 1.9 million of the Company’s common stock from the Notes due 2025 Hedge settlement and issued 1.8 million of the Company’s common stock from the 2025 Warrants that were unwound. Following the unwind transactions summarized above, as of December 31, 2021, options to purchase approximately 1.3 million shares of common stock remained outstanding under the Notes due 2025 Hedge, and 2025 Warrants exercisable to purchase approximately 1.3 million shares remained outstanding.

For the period from March 9, 2020, the issuance date of the Notes due 2025 Hedge and 2025 Warrants, through May 19, 2020, the number of authorized and unissued shares of the Company’s common stock that are not reserved for other purposes was less than the maximum number of underlying shares that will be required to settle the Notes due 2025 through the delivery of shares of the Company’s common stock. Accordingly, the Notes due 2025 Hedge and 2025 Warrants could only be settled on net cash settlement basis. As a result, the Notes due 2025 Hedge and 2025 Warrants were classified as a Convertible notes hedge asset and Warrants liability, respectively, in the consolidated balance sheet and the change in fair value of derivatives was included in other expense, net in the consolidated statement of operations.

On May 20, 2020, at the Company’s annual meeting of stockholders, the stockholders approved the Amendment and satisfied the Share Reservation Condition (as discussed above), and as a result, the Convertible notes hedge asset and Warrants liabilities were remeasured at a fair value of $117.1 million and $96.4 million, respectively, and were then reclassified to additional paid-in-capital in the consolidated balance sheet in the second quarter of 2020 and is no longer remeasured as long as they continue to meet the conditions for equity classification. The change in the fair value of the Convertible notes hedge asset and Warrants liability were recorded in other expense, net in the consolidated statements of operations during the twelve months ended December 31, 2020.

Convertible Senior Notes due 2024

On June 5, 2019, the Company issued $132.0 million aggregate principal amount of 1.0% convertible senior notes due 2024 (the “Notes due 2024”). The Notes due 2024 are general unsecured obligations and bear interest at an annual rate of 1.0% per year, payable semi-annually on June 1 and December 1 of each year, beginning December 1, 2019. The Notes due 2024 are governed by an indenture between the Company and U.S. Bank National Association, as trustee. The Notes due 2024 will mature on June 1, 2024, unless earlier repurchased by the Company or converted at the option of the holders. The Company may not redeem the notes prior to the maturity date, and no sinking fund is provided for the notes. The Notes due 2024 may be converted, under certain circumstances as described below, based on an initial conversion rate of 48.7781 shares of common stock per $1,000 principal amount (which represents an initial conversion price of $20.50 per share). The conversion rate for the Notes due 2024 will be subject to adjustment upon the occurrence of certain specified events but will not be adjusted for accrued and unpaid interest. In addition, upon the occurrence of a make-whole fundamental change (as defined in the relevant indenture), the Company will, in certain circumstances, increase the conversion rate by a number of additional shares for a holder that elects to convert its notes in connection with such make-whole fundamental change. The Company received approximately $128.0 million in net proceeds, after deducting the initial purchasers’ discount, from the issuance of the Notes due 2024.

For accounting of Company’s Notes due 2024, refer Note 13. “Debt,” of the notes to consolidated financial statements included in Part II, Item 8 of Annual Report on Form 10-K for the fiscal year ended December 31, 2020.

During the year ended December 31, 2021, $88.1 million in aggregate principal amount of the Notes due 2024 were converted or repurchased by the Company, and the principal amount of the converted and repurchased Notes due 2024 was repaid in cash. Of the $88.1 million in aggregate principal amount, $25.5 million in aggregate principal amount of Notes due 2024 were repurchased by the Company pursuant to separately- and privately-negotiated exchange agreements entered into in March 2021 concurrently with the issuance of Notes due 2026 and Notes due 2028. In connection with such conversions and repurchases, during the year ended December 31, 2021, the Company also issued 3.8 million shares of its common stock to the holders of the converted and repurchased Notes due 2024, with an aggregate fair value of $669.5 million, representing the conversion value in excess of the principal amount of the Notes due 2024. The total amount of $88.1 million paid to settle the conversions and repurchases of the Notes due 2024 during 2021 was allocated between the liability and equity components of the amount extinguished by determining the fair value of the liability component immediately prior to the notes settlement and allocating that portion of the conversion price to the liability component in the amount of $79.5 million. The residual of the conversion price of $8.7 million was allocated to the equity component of the Notes due 2024 as a reduction of additional paid-in capital. As part of the settlement of the conversions and repurchases, the Company wrote-off the $16.8 million unamortized debt discount and $1.4 million debt issuance cost apportioned to the principal amount of Notes due 2024 were converted and repurchased. The Company also recorded a loss on partial settlement of the converted and repurchased Notes due 2024 of $9.6 million in Other income (expense), net in the year ended December 31, 2021, representing the difference between the

consideration attributed to the liability component and the sum of the net carrying amount of the liability component and unamortized debt issuance costs. Following the conversions and repurchases summarized above, the Notes due 2024 are no longer outstanding.

The following table presents the total amount of interest cost recognized in the statement of operations relating to the Notes due 2024:


	Years Ended December 31,
		2021		2020
		(In thousands)
Contractual interest expense		$	8	$	1,284
Amortization of debt discount		772		6,325
Amortization of debt issuance costs		74		646
Total interest cost recognized		$	854	$	8,255

Notes due 2024 Hedge and Warrant Transactions

In connection with the offering of the Notes due 2024, the Company entered into privately-negotiated convertible note hedge transactions (the “Notes due 2024 Hedge”) pursuant to which the Company has the option to purchase a total of approximately 6.4 million shares of its common stock (subject to anti-dilution adjustments), which is the same number of shares initially issuable upon conversion of the notes, at a price of $20.50 per share, which is the initial conversion price of the Notes due 2024. The total cost of the convertible note hedge transactions was approximately $36.3 million. The Notes due 2024 Hedge transactions are expected generally to reduce potential dilution to the Company’s common stock upon any conversion of the Notes due 2024 and/or offset any cash payments the Company is required to make in excess of the principal amount of converted notes, as the case may be.

Additionally, the Company separately entered into privately-negotiated warrant transactions in connection with the offering of the Notes due 2024 (the “2024 Warrants”) whereby the Company sold warrants to acquire approximately 6.4 million shares of the Company’s common stock (subject to anti-dilution adjustments) at an initial strike price of $25.23 per share. The Company received aggregate proceeds of approximately $29.8 million from the sale of the 2024 Warrants. If the market value per share of the Company’s common stock, as measured under the 2024 Warrants, exceeds the strike price of the 2024 Warrants, the 2024 Warrants will have a dilutive effect on the Company’s earnings per share, unless the Company elects, subject to certain conditions, to settle the 2024 Warrants in cash. Taken together, the purchase of the Notes due 2024 Hedge transactions and the sale of the 2024 Warrants are intended to reduce potential dilution from the conversion of the Notes due 2024 and to effectively increase the overall conversion price from $20.50 to $25.23 per share. The 2024 Warrants are only exercisable on the applicable expiration dates in accordance with the 2024 Warrants. Subject to the other terms of the 2024 Warrants, the first expiration date applicable to the 2024 Warrants is September 1, 2024, and the final expiration date applicable to the 2024 Warrants is April 22, 2025.

During the year ended December 31, 2021, in connection with the repurchase of $25.5 million aggregate principal amount of the Notes due 2024 summarized above, the Company entered into partial unwind agreements with respect to certain of the Notes due 2024 Hedge and received 1.1 million shares of its common stock as a termination payment for the portion of the Notes due 2024 Hedge that were unwound.

In addition to the unwind transactions discussed above, the Company also received 2.7 million shares of the Company’s common stock from the Notes due 2024 Hedge settlements as a result of the conversion of $62.6 million in aggregate principal amount of the Notes due 2024 in 2021. In addition, the Company entered into partial unwind agreements with respect to certain of the 2024 Warrants in connection with the repurchase and conversion of $88.1 million in aggregate principal amount of the Notes due 2024 during 2021 and issued 3.8 million shares of its common stock as a termination payment for the portion of the 2024 Warrants that were unwound. Following the transactions summarized above, Notes due 2024 Hedge and 2024 Warrants are no longer outstanding.

Convertible Senior Notes due 2023

In August 2018, the Company sold $65.0 million aggregate principal amount of 4.0% convertible senior notes due 2023 (the “Notes due 2023”) in a private placement. On May 30, 2019, the Company entered into separately and privately-negotiated transactions with certain holders of the Notes due 2023 resulting in the repurchase and exchange, as of June 5, 2019, of $60.0 million aggregate principal amount of the notes in consideration for the issuance of 10,801,080 shares of common stock and separate cash payments totaling $6.0 million. As of both December 31, 2021 and December 31, 2020, $5.0 million aggregate principal amount of the Notes due 2023 remained outstanding.

The remaining outstanding Notes due 2023 are general unsecured obligations and bear interest at a rate of 4.0% per year, payable semi-annually on February 1 and August 1 of each year. The Notes due 2023 are governed by an indenture between the Company and U.S. Bank National Association, as trustee. The remaining outstanding Notes due 2023 will mature on August 1, 2023, unless earlier repurchased by the Company or converted at the option of the holders. The Company may not redeem the remaining Notes due 2023 prior to the maturity date, and no sinking fund is provided for such notes. The remaining Notes due 2023 are convertible, at a holder’s election, in multiples of $1,000 principal amount, into shares of the Company’s common stock based on the applicable conversion rate. The initial conversion rate for such notes is 180.018 shares of common stock per $1,000 principal amount of notes (which is equivalent to an initial conversion price of approximately $5.56 per share). The conversion rate and the corresponding conversion price are subject to adjustment upon the occurrence of certain events but will not be adjusted for any accrued and unpaid interest. Holders of the remaining Notes due 2023 who convert their notes in connection with a make-whole fundamental change (as defined in the applicable indenture) are, under certain circumstances, entitled to an increase in the conversion rate. Additionally, in the event of a fundamental change, holders of the remaining Notes due 2023 may require the Company to repurchase all or a portion of their notes at a price equal to 100% of the principal amount of notes, plus any accrued and unpaid interest, including any additional interest to, but excluding, the repurchase date. Holders may convert all or any portion of their Notes due 2023 at their option at any time prior to the close of business on the business day immediately preceding the maturity date, in multiples of $1,000 principal amount.

The following table presents the amount of interest cost recognized relating to the contractual interest coupon and the amortization of debt issuance costs of the Notes due 2023.



	Years Ended December 31,
		2021		2020
		(In thousands)
Contractual interest expense		$	200	$	200

Amortization of debt issuance costs		40		40
Total interest costs recognized		$	240	$	240

Sale of Long-Term Financing Receivables

The Company entered into an agreement with a third party in the fourth quarter of 2017 to sell certain current and future receivables at a discount. In December 2017, the third party made an initial purchase of receivables that resulted in net proceeds to the Company of $2.8 million. This transaction was recorded as debt on the accompanying consolidated balance sheets, and the debt balance was relieved in January 2019 as the underlying receivables were settled. During the year ended December 31, 2018, the third party made three additional purchases of receivables that resulted in total net proceeds to the Company of $5.6 million. These transactions were recorded as debt on the accompanying consolidated balance sheets, and the total associated debt balance was relieved by December 2021 as the underlying receivables are settled. As of December 31, 2021, the total sale of long-term financing receivable recorded as debt are no longer outstanding.

COMMITMENTS AND CONTINGENCIES

12 Months Ended

Dec. 31, 2021

Commitments and Contingencies Disclosure [Abstract]

COMMITMENTS AND CONTINGENCIES

Operating Leases

The Company leases office facilities under noncancelable operating leases that expire on various dates through 2032, some of which may include options to extend the leases for up to 12 years.

The components of lease expense are presented as follows:


	Years Ended December 31,
		2021		2020
		(In thousands)
Operating lease costs		$	7,049	$	5,332

The components of lease liabilities are presented as follows:


	December 31, 2021		December 31, 2020
	(In thousands)
Operating lease liabilities, current (Accrued liabilities)	$	3,830	$	4,542
Operating lease liabilities, non-current (Other liabilities)	11,920		15,209
Total operating lease liabilities	$	15,750	$	19,751

Supplemental lease information:
Weighted average remaining lease term	5.9 years		6.4 years
Weighted average discount rate	7.4%		7.7%

Supplemental cash flow and other information related to operating leases, are as follows:


	Years Ended December 31,
		2021		2020
		(In thousands)
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases		$	5,855	$	4,762

Non-cash investing activities:
Lease liabilities arising from obtaining right-of-use assets		$	708	$	10,625

Undiscounted cash flows of operating lease liabilities as of December 31, 2021 are as follows:


	Lease Amounts
	(In thousands)
Year:
2022	$	4,771
2023	4,160
2024	3,198
2025	2,422
2026	1,395
Thereafter	2,680
Total lease payments	18,626
Less: imputed lease interest	(2,876)
Total lease liabilities	$	15,750

As of December 31, 2021, we have an additional operating lease commitment of $5.6 million for an office lease that has not yet commenced. The operating lease commitment will commence in the first quarter of 2022 with a lease term of 10.0 years.

Purchase Obligations

The Company has contractual obligations related to component inventory that its contract manufacturers procure on its behalf in accordance with its production forecast as well as other inventory related purchase commitments. As of December 31, 2021, these purchase obligations totaled approximately $424.6 million.

Litigation

The Company is subject to various legal proceedings relating to claims arising out of its operations that have not been fully resolved. The outcome of litigation is inherently uncertain. If one or more legal matters were resolved against the Company in a reporting period for amounts above management’s expectations, the Company’s business, results of operations, financial position and cash flows for that reporting period could be materially adversely affected. As of December 31, 2021 and February 11, 2022, the Company is not currently a party to any matters that management expects will have an adverse material effect on the Company’s consolidated financial position, results of operations or cash flows.

Contingencies

On March 26, 2020, the Office of the United States Trade Representative (the “USTR”) announced certain exclusion requests related to tariffs on Chinese imported microinverter products that fit the dimensions and weight limits within a Section 301 Tariff exclusion under U.S. note 20(ss)(40) to subchapter III of chapter 99 of the Harmonized Tariff Schedule of the United States (the “Tariff Exclusion”). The Tariff Exclusion applies to covered products under the China Section 301 Tariff Actions (“Section 301 Tariffs”) taken by the USTR exported from China to the United States from September 24, 2018 until August 7, 2020. Accordingly, the Company sought refunds totaling approximately $38.9 million plus approximately $0.6 million accrued interest on tariffs previously paid from September 24, 2018 to March 31, 2020 for certain microinverters that qualify for the Tariff Exclusion. The refund request was subject to review and approval by the U.S. Customs and Border Protection; therefore, the Company assessed the probable loss recovery in the year ended December 31, 2020 was equal to the approved refund requests available to the Company.

As of December 31, 2020, the Company had received $24.8 million of tariff refunds and accrued for the remaining $14.7 million tariff refunds that were approved, however, not yet received on or before December 31, 2020. As of March 31, 2021, the Company received the remaining $14.7 million tariff refunds. For the year ended December 31, 2020, the Company recorded $38.9 million as a reduction to cost of revenues in the Company’s consolidated statement of operations as the approved refunds relate to paid tariffs previously recorded to cost of revenues, therefore, the Company recorded the corresponding approved tariff refunds as credits to cost of revenues in the fourth quarter of 2020. For the year ended December 31, 2020, the Company recorded the $0.6 million accrued interest as interest income in the consolidated statement of operations. The tariff refund receivable of zero and $14.7 million was recorded as a reduction of accounts payable to Flex Ltd. and affiliates (“Flex”), the Company’s manufacturing partner and the importer of record who will first receive the tariff refunds, on the Company’s consolidated balance sheet as of December 31, 2021 and December 31, 2020, respectively.

The Tariff Exclusion expired on August 7, 2020 and those microinverter products now are subject to tariffs. The Company also continues to pay Section 301 Tariffs on its storage and communication products and other accessories imported from China which are not subject to the Tariff Exclusion.

STOCKHOLDERS' EQUITY	12 Months Ended
STOCKHOLDERS' EQUITY	Dec. 31, 2021
Equity [Abstract]
STOCKHOLDERS' EQUITY	STOCKHOLDERS' EQUITY On May 19, 2021, at the Company’s annual meeting of stockholders, the stockholders approved an amendment to the Amended and Restated Certificate of Incorporation to increase the number of authorized shares of the Company’s common stock, par value $0.00001 per share, from 200,000,000 shares to 300,000,000 shares (the “Amendment”). The Amendment became effective upon filing with the Secretary of State of Delaware on May 19, 2021. In April 2020, the Company’s board of directors authorized the repurchase of up to $200.0 million of the Company’s common stock, exclusive of brokerage commissions (the “2020 Repurchase Program”). During the second quarter of 2021, the Company repurchased and subsequently retired approximately 1.7 million shares of common stock from the open market at an average cost of $117.47 per share for a total of $200.0 million. The transaction is recorded as “Repurchase of common stock” in the accompanying consolidated statements of changes in stockholders’ equity. In May 2021, the board of directors authorized a new share repurchase program (the “2021 Repurchase Program”) pursuant to which the Company may repurchase up to an additional $500.0 million of the Company’s common stock. Purchases may be completed from time to time in the open market or through structured repurchase agreements with third parties. The program may be discontinued or amended at any time and expires on May 13, 2024. During the fourth quarter of 2021, the Company repurchased and subsequently retired approximately 1.5 million shares of common stock from the open market at an average cost of $196.98 per share for a total of $300.0 million. As of December 31, 2021, the Company has approximately $200.0 million remaining for repurchase of shares under the 2021 Repurchase Program.

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

+ References

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+ Details

STOCK-BASED COMPENSATION

12 Months Ended

Dec. 31, 2021

Share-based Payment Arrangement [Abstract]

STOCK-BASED COMPENSATION

2011 Plan

Under the 2011 Equity Incentive Plan (the “2011 Plan”), the Company could initially issue up to 2,643,171 shares of its common stock pursuant to stock options, stock appreciation rights (“SARS”), restricted stock awards (“RSA”), RSUs, PSUs, and other forms of equity compensation, or collectively, stock awards, all of which may be granted to employees, including officers, and to non-employee directors and consultants. Options granted under the 2011 Plan before August 1, 2012 generally expire 10 years after the grant date and options granted thereafter generally expire 7 years after the grant date. Equity awards granted under the 2011 Plan generally vest over a 4-year period from the date of grant based on continued employment. As of May 19, 2021, no further stock options or other stock awards may be granted under the 2011 Plan.

2021 Plan

On May 19, 2021, at the 2021 annual meeting of stockholders of the Company, the stockholders approved the 2021 Equity Incentive Plan (the “2021 Plan”), as the successor to the 2011 Plan. The 2021 Plan provides for the grant of incentive stock options, SARS, RSAs, RSUs, PSUs other stock awards. Eligible participants under the 2021 Plan include Company’s employees, directors and consultants. The 2021 Plan provides, among other things, that the number of shares of the Company’s common stock, $0.00001 par value per share (“Common Stock”), reserved for issuance under the 2021 Plan (subject to adjustment for certain changes in the Company’s capitalization) is equal to: (A) the sum of (i) 9,100,456 newly reserved shares of Common Stock and (ii) 5,256,517 Returning Shares (as defined below) as such shares become available from time to time as set forth in the 2021 Plan. “Returning Shares” means shares subject to any outstanding award granted under the 2011 Plan (“Prior Plan Award”) that are (i) not issued because such Prior Plan Award or any portion thereof expires or otherwise terminates without all of the shares covered by such Prior Plan Award having been issued, or is settled in cash; (ii) forfeited back to or repurchased by the Company because of a failure to vest; or (iii) reacquired or withheld (or not issued) by the Company to satisfy the purchase price of, or a tax withholding obligation in connection with, a Prior Plan Award that is a Full Value Award (as defined in the 2021 Plan). As a result of the approval of the 2021 Plan, no additional awards may be granted from the 2011 Plan. As of December 31, 2021, 7,963,894 shares remained available for issuance pursuant to future grants under the 2021 Plan.

2011 Employee Stock Purchase Plan

The 2011 Employee Stock Purchase Plan (“ESPP”) became effective immediately upon the execution and delivery of the underwriting agreement for the Company’s initial public offering on March 29, 2012. The ESPP authorized the issuance of 669,603 shares of the Company’s common stock pursuant to purchase rights granted to employees. The number of shares of common stock reserved for issuance will automatically increase, on each January 1, by a lesser of (i) 330,396 shares of the Company’s common stock or (ii) 1.0% of the total number of shares of the Company’s common stock outstanding on December 31 of the preceding calendar year, as determined by the Company’s board of directors. At the Annual Meeting of Stockholders held on May 18, 2017 the Company’s stockholders approved a one-time amendment to the Company’s ESPP to increase the aggregate number of shares available for purchase by 400,000 shares and to increase the annual automatic minimum increase in shares reserved for issuance from 330,396 to 700,000 shares effective January 1, 2018. As of December 31, 2021, 1,754,231 shares remained available for future issuance under the ESPP. On January 1, 2022, the shares available for issuance under the ESPP automatically increased by 700,000 shares.

The ESPP is implemented by concurrent offering periods and each offering period may contain up to four interim purchase periods. In general, offering periods consist of the 24-month periods commencing on each May 15 and November 15 of a calendar year.

Generally, all full-time employees in Australia, Canada, China, France, Germany, India, Mexico, New Zealand, the Netherlands and the United States, including executive officers, are eligible to participate in the ESPP. The ESPP permits eligible employees to purchase the Company’s common stock through payroll deductions, which may not exceed 15% of the employee’s total compensation subject to certain limits. Stock may be purchased under the plan at a price equal to 85% of the fair market value of the Company’s stock on either the date of purchase or the first day of an offering period, whichever is lower. A two‑year look-back feature in the Company’s ESPP causes an offering period to reset if the fair value of the Company’s common stock on a purchase date is less than that on the initial offering date for that offering period. The reset feature, when triggered, will be accounted for as a modification to the original offering, resulting in additional expense to be recognized over the 24-month period of the new offering. During any calendar year, participants may not purchase shares of common stock having a value greater than $25,000, based on the fair market value per share of the common stock at the beginning of an offering period.

Valuation of Equity Awards

Stock Options

The fair value of each option granted was estimated on the date of grant using the Black-Scholes option-pricing model with the following assumptions:

•Expected term - The expected term of the option awards represents the period of time between the grant date of the option awards and the date the option awards are either exercised, converted or canceled, including an estimate for those option awards still outstanding. The Company used the simplified method, as permitted by the SEC for companies with a limited history of stock option exercise activity, to determine the expected term for its option grants.

•Expected volatility - The expected volatility was calculated based on the Company’s historical stock prices, supplemented as necessary with historical volatility of the common stock of several peer companies with characteristics similar to those of the Company.

•Risk-free interest rate - The risk-free interest rate was based on the U.S. Treasury yield curve in effect at the time of grant and with a maturity that approximated the Company’s expected term.

•Dividend yield - The dividend yield was based on the Company’s dividend history and the anticipated dividend payout over its expected term.

The following table presents the weighted-average grant date fair value of options granted for the periods presented and the assumptions used to estimate those values using a Black-Scholes option pricing model.


	Years Ended December 31,
		2021	2020		2019
Weighted average grant date fair value		**	$	38.45	$	9.16
Expected term (in years)		**	3.8		3.8
Expected volatility		**	86.4%		89.1%
Annual risk-free rate of return		**	0.1%		2.1%
Dividend yield		**	—%		—%

** No stock options were granted during the year ended December 31, 2021.

Restricted Stock Units

The fair value of the Company’s RSU awards granted is based upon the closing price of the Company’s stock price on the date of grant.

Performance Stock Units

The fair value of the Company’s non-market PSU awards granted was based upon the closing price of the Company’s stock price on the date of grant. The fair value of awards of the Company’s PSU awards containing

market conditions was determined using a Monte Carlo simulation model based upon the terms of the conditions, the expected volatility of the underlying security, and other relevant factors.

Stock-based Compensation Expense

Stock-based compensation expense for all stock-based awards expected to vest is measured at fair value on the date of grant and recognized ratably over the requisite service period. The following table summarizes the components of total stock-based compensation expense included in the consolidated statements of operations for the periods presented.


	Years Ended December 31,
		2021		2020		2019
		(In thousands)
Cost of revenues		$	7,366	$	3,759	$	1,650
Research and development		33,927		12,701		4,897
Sales and marketing		37,434		11,548		5,678
General and administrative		35,559		14,495		7,216
Restructuring		—		—		735
Total		$	114,286	$	42,503	$	20,176
Income tax benefit included in the provision for incomes taxes		$	97,129	$	61,389	$	8,185

The following table summarizes the various types of stock-based compensation expense for the periods presented.


	Years Ended December 31,
		2021		2020		2019
		(In thousands)
Stock options, RSUs and PSUs		$	110,142	$	39,841	$	19,216
Employee stock purchase plan		4,144		2,662		960

Total		$	114,286	$	42,503	$	20,176

As of December 31, 2021, there was approximately $254.6 million of total unrecognized stock-based compensation expense related to unvested equity awards, which are expected to be recognized over a weighted-average period of 2.8 years.

Equity Awards Activity

Stock Options

The following is a summary of stock option activity.


	Number of Shares Outstanding	Weighted- Average Exercise Price per Share		Weighted- Average Remaining Contractual Term	Aggregate Intrinsic Value (1)
	(In thousands)			(Years)	(In thousands)
Outstanding at December 31, 2018	6,772	$	1.76
Granted	43	14.58
Exercised	(2,616)	1.22			$	31,093
Canceled	(102)	4.07
Outstanding at December 31, 2019	4,097	$	2.18
Granted	11	64.17
Exercised	(1,494)	2.74			$	114,089
Canceled	(82)	6.94
Outstanding at December 31, 2020	2,532	$	1.96
Granted	—	—
Exercised	(267)	2.44			$	42,091
Canceled	(1)	0.83
Outstanding at December 31, 2021	2,264	$	1.90	2.8	$	409,834
Vested and expected to vest at December 31, 2021	2,264	$	1.90	2.8	$	409,834
Exercisable at December 31, 2021	2,262	$	1.90	2.8	$	409,550

(1) The intrinsic value of options exercised is based upon the value of the Company’s stock at exercise. The intrinsic value of options outstanding, vested and expected to vest, and exercisable as of December 31, 2021 is based on the closing price of the last trading day during the period ended December 31, 2021. The Company’s stock fair value used in this computation was $182.94 per share.

The following table summarizes information about stock options outstanding at December 31, 2021.


	Options Outstanding				Options Exercisable
Range of Exercise Prices	Number of Shares	Weighted- Average Remaining Life	Weighted- Average Exercise Price		Number of Shares	Weighted- Average Exercise Price
	(In thousands)	(Years)			(In thousands)
$0.70 —– $1.11	486	3.3	$	0.86	486	$	0.85
$1.29 —– $1.29	1,000	2.7	1.29		1,000	1.28
$1.31 —– $1.31	556	2.3	1.31		556	1.31
$1.53 —– $14.58	211	3.1	5.65		209	5.65
$64.17 —– $64.17	11	5.4	64.17		11	64.17
Total	2,264	2.8	$	1.90	2,262	$	1.90

Restricted Stock Units

The following is a summary of RSU activity.


	Number of Shares Outstanding	Weighted- Average Fair Value per Share at Grant Date		Weighted- Average Remaining Contractual Term	Aggregate Intrinsic Value (1)
	(In thousands)			(Years)	(In thousands)
Outstanding at December 31, 2018	4,352	$	3.52
Granted	2,112	11.50
Vested	(1,707)	3.87			$	27,156
Canceled	(494)	4.81
Outstanding at December 31, 2019	4,263	$	7.19
Granted	1,550	55.66
Vested	(2,085)	7.26			$	125,578
Canceled	(140)	19.47
Outstanding at December 31, 2020	3,588	$	27.61
Granted	1,301	179.88
Vested	(1,979)	20.47			$	364,665
Canceled	(124)	88.50
Outstanding at December 31, 2021	2,786	$	100.73	1.2	$	509,864
Expected to vest at December 31, 2021	2,786	$	100.73	1.2	$	509,864

(1) The intrinsic value of RSUs vested is based upon the value of the Company’s stock when vested. The intrinsic value of RSUs outstanding and expected to vest as of December 31, 2021 is based on the closing price of the last trading day during the period ended December 31, 2021. The Company’s stock fair value used in this computation was $182.94 per share.

Performance Stock Units

The following is a summary of PSU activity.


	Number of Shares Outstanding	Weighted- Average Fair Value per Share at Grant Date		Weighted- Average Remaining Contractual Term	Aggregate Intrinsic Value (1)
	(In thousands)			(Years)	(In thousands)
Outstanding at December 31, 2018	1,330	$	4.66
Granted	1,052	9.48
Vested	(1,063)	4.62			$	10,818
Canceled	(364)	5.16
Outstanding at December 31, 2019	955	$	9.83
Granted	989	31.12
Vested	(1,450)	10.20			$	52,144
Canceled	—	—
Outstanding at December 31, 2020	494	$	51.10
Granted	715	131.60
Vested	(494)	59.19			$	91,803
Canceled	(270)	52.75
Outstanding at December 31, 2021	445	$	169.82	0.2	$	81,456

(1) The intrinsic value of PSUs vested is based upon the value of the Company’s stock when vested. The intrinsic value of PSUs outstanding and expected to vest as of December 31, 2021 is based on the closing price of the last trading day during the period ended December 31, 2021. The Company’s stock fair value used in this computation was $182.94 per share.

Employee Stock Purchase Plan

A summary of ESPP activity for the years presented is as follows: (in thousands, except per share data):


	Years Ended December 31,
	2021		2020		2019
Proceeds from common stock issued under ESPP	$	6,832	$	4,304	$	1,692
Shares of common stock issued	235		347		315
Weighted-average price per share	$	29.12	$	12.41	$	5.37

INCOME TAXES

12 Months Ended

Dec. 31, 2021

Income Tax Disclosure [Abstract]

INCOME TAXES

The domestic and foreign components of income before income taxes consisted of the following:


	Years Ended December 31,
	2021		2020		2019
	(In thousands)
United States	$	102,886	$	112,727	$	85,520
Foreign	18,042		6,683		4,594
Income before income taxes	$	120,928	$	119,410	$	90,114

The income taxes (benefit) for the years presented is as follows:


	Years Ended December 31,
	2021		2020		2019
	(In thousands)
Current:
Federal	$	—	$	—	$	—
State	488		636		327
Foreign	6,232		1,896		1,589
	6,720		2,532		1,916
Deferred:
Federal	(28,398)		(13,445)		(56,959)
State	(4,380)		(3,672)		(17,458)
Foreign	1,537		—		1,467
	(31,241)		(17,117)		(72,950)
Income taxes (benefit)	$	(24,521)	$	(14,585)	$	(71,034)

A reconciliation of the income taxes (benefit) provision and the amount computed by applying the statutory federal income tax rate of 21% to income before income taxes for the years presented is as follows:


	Years Ended December 31,
	2021		2020		2019
	(In thousands)
Income tax (benefit) provision at statutory federal rate	$	27,681	$	25,076	$	18,929
State taxes, net of federal benefit	489		(3,098)		(17,197)
Change in valuation allowance	—		—		(71,300)
Foreign tax rate and tax law differential	1,073		611		1,206
Tax credits	(15,632)		(5,835)		(1,803)
Stock-based compensation	(80,950)		(50,818)		(8,072)
Other permanent items	178		(253)		31

Other nondeductible/nontaxable items	2,316		1,525		2,765
Uncertain tax positions	6,911		1,530		504

GILTI	—		—		1,086
Section 162(m)	25,812		11,469		2,817
Convertible note settlements	8,223		—		—
Warrant mark-to-mark adjustment	(622)		5,208		—
Income tax (benefit)	$	(24,521)	$	(14,585)	$	(71,034)

A summary of significant components of the Company’s deferred tax assets and liabilities as of December 31, 2021 and 2020 is as follows:


	December 31,
	2021		2020
	(In thousands)
Deferred tax assets:
Allowances and reserves	$	18,764	$	13,146
Net operating loss and tax credit carryforwards	65,699		53,116
Stock-based compensation	12,935		4,598
Deferred revenue	27,778		20,765
Fixed assets and intangibles	39,711		8,706
Sec. 163(j) interest carryforward	10,749		4,401
Other	1,609		7,007
Subtotal	177,245		111,739

Total deferred tax assets	177,245		111,739
Deferred tax liabilities:
Goodwill	(31,805)		(1,719)
Unremitted foreign earnings	(2,226)		(7)
Deferred cost of goods sold	(23,713)		(17,545)
Total deferred tax liabilities	(57,744)		(19,271)
Net deferred tax asset	$	119,501	$	92,468

The Company's accounting for deferred taxes involves the evaluation of a number of factors concerning the realizability of the Company's deferred tax assets. Assessing the realizability of deferred tax assets is dependent upon several factors, including the likelihood and amount, if any, of future taxable income in relevant jurisdictions during the periods in which those temporary differences become deductible. The Company's management forecasts taxable income by considering all available positive and negative evidence including its history of operating income or losses and its financial plans and estimates which are used to manage the business. These assumptions require significant judgment about future taxable income. The amount of deferred tax assets considered realizable is subject to adjustment in future periods if estimates of future taxable income are reduced.

The Company has net operating loss carryforwards for federal and California income tax purposes of approximately $153.9 million and $92.8 million, respectively, as of December 31, 2021. The federal and state net operating loss carryforwards, if not utilized, will expire beginning in 2036 and 2029, respectively.

The Company has approximately $17.3 million of federal research credit and $9.8 million of state research credit carryforwards. The federal credits begin to expire in 2026 and the state credits can be carried forward indefinitely.

Utilization of some of the federal and state net operating loss and credit carryforwards are subject to annual limitations due to the “change in ownership” provisions of the Internal Revenue Code of 1986 and similar state provisions. The Company has completed a Section 382 analysis through December 31, 2021, which indicated no such change has occurred through December 31, 2021.

The accounting for uncertain tax positions prescribes a recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. The Company is required to recognize in the financial statements the impact of a tax position, if that position is more-likely-than-not of being sustained on audit, based on the technical merits of the position. The Company recorded a net charge for unrecognized tax benefits in 2021 of $12.5 million.

The Company does not have any tax positions for which it is reasonably possible the total amount of gross unrecognized tax benefits will increase or decrease over the next year. The unrecognized tax benefits may increase or change during the next year for items that arise in the ordinary course of business.

A tabular reconciliation of the total amounts of unrecognized tax benefits for the years presented is as follows (in thousands):


	Years Ended December 31,
	2021		2020		2019
Unrecognized tax benefits—at beginning of year	$	8,421	$	6,589	$	6,325
Increases in balances related to tax positions taken in prior years	4,391		—		—
Decreases in balances related to tax positions taken in prior years	—		—		(370)
Increases in balances related to tax positions taken in current year	8,301		2,006		771

Lapses in statutes of limitations	(209)		(174)		(137)
Unrecognized tax benefits—at end of year	$	20,904	$	8,421	$	6,589

The Company includes interest and penalties related to unrecognized tax benefits within the income tax benefit (provision). In the years ended December 31, 2021, 2020 and 2019, the total amount of gross interest and penalties accrued in each year was immaterial. Both the unrecognized tax benefits and the associated interest and penalties that are not expected to result in payment or receipt of cash within one year are classified as other non-current liabilities in the consolidated balance sheets. In connection with tax matters, the Company’s interest and penalty expense recognized in 2021, 2020 and 2019 in the consolidated statements of operations was immaterial.

The Company’s tax returns continue to remain effectively subject to examination by U.S. federal authorities for the years 2006 through 2021 and by California state authorities for the years 2006 through 2021 due to use and carryovers of net operating losses and credits.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 21
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32857-109319

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+ Details

CONCENTRATION OF CREDIT RISK AND MAJOR CUSTOMERS	12 Months Ended
CONCENTRATION OF CREDIT RISK AND MAJOR CUSTOMERS	Dec. 31, 2021
Risks and Uncertainties [Abstract]
CONCENTRATION OF CREDIT RISK AND MAJOR CUSTOMERS	CONCENTRATION OF CREDIT RISK AND MAJOR CUSTOMERS The Company is potentially subject to financial instrument concentration of credit risk through its cash, cash equivalents, marketable securities, and accounts receivable. The Company places its cash, cash equivalents and marketable securities with high quality institutions and performs periodic evaluations of their relative credit standing. Accounts receivable can be potentially exposed to a concentration of credit risk with its major customers. As of December 31, 2021 and 2020, amounts due from one customer represented approximately 38% and 36%, respectively, of the total accounts receivable balance. In 2021, one customer accounted for approximately 34% of total net revenues. In 2020, one customer accounted for approximately 29% of total net revenues. In 2019, two customers accounted for approximately 21% and 12% of total net revenues.

NET INCOME PER SHARE

12 Months Ended

Dec. 31, 2021

Earnings Per Share [Abstract]

NET INCOME PER SHARE

Basic net income per share is computed by dividing net income by the weighted average number of shares of common stock outstanding during the period. Diluted net income per share is computed in a similar manner, but it also includes the effect of potential common shares outstanding during the period, when dilutive. Potential common shares include Stock Options, RSUs, PSUs, shares to be purchased under the Company’s ESPP, the Notes due 2023, Notes due 2024, Notes due 2025, Notes due 2026, Notes due 2028, 2024 Warrants, 2025 Warrants, 2026 Warrants, and the 2028 Warrants. See Note 13. “Debt,” of the notes to the consolidated financial statements included in Part II, Item 8 of this Annual Report on Form 10-K for additional information.

The dilutive effect of potentially dilutive common shares is reflected in diluted earnings per share by application of the treasury stock method for stock options, RSUs, PSUs, the Notes due 2024, the Notes due 2025, the Notes due 2026, the Notes due 2028, the 2024 Warrants, the 2025 Warrants, the 2026 Warrants and the 2028 Warrants. To the extent these potential common shares are antidilutive, they are excluded from the calculation of diluted net income per share.

The following table presents the computation of basic and diluted net income per share for the periods presented.


	Years Ended December 31,
		2021		2020		2019
		(In thousands, except per share data)
Numerator:
Net income		$	145,449	$	133,995	$	161,148
Notes due 2023 interest and financing costs, net		177		177		1,088
Adjusted net income		$	145,626	$	134,172	$	162,236

Denominator:
Shares used in basic per share amounts:
Weighted average common shares outstanding		134,025		125,561		116,713

Shares used in diluted per share amounts:
Weighted average common shares outstanding		134,025		125,561		116,713
Effect of dilutive securities:
Employee stock-based awards		4,918		6,997		8,964
Notes due 2023		900		900		5,516
Notes due 2024		768		4,449		451
2024 Warrants		647		4,011		—
Notes due 2025		929		—		—
2025 Warrants		691		—		—




Weighted average common shares outstanding for diluted calculation		142,878		141,918		131,644

Basic and diluted net income per share
Net income per share, basic		$	1.09	$	1.07	$	1.38
Net income per share, diluted		$	1.02	$	0.95	$	1.23

The following outstanding shares of common stock equivalents were excluded from the calculation of the diluted net income per share attributable to common stockholders because their effect would have been antidilutive.


	Years Ended December 31,
		2021	2020	2019
		(In thousands)



Employee stock-based awards		32	43	185
Notes due 2028		1,082	—	—
2028 Warrants		2,184	—	—
Notes due 2026		1,328	—	—
2026 Warrants		2,225	—	—
Notes due 2025		—	197
2025 Warrants		—	1,254	—


2024 Warrants		—	—	300


Total		6,851	1,494	485

Diluted earnings per share for the year ended December 31, 2021 includes the dilutive effect of stock options, RSUs, PSUs, shares to be purchased under the ESPP, the Notes due 2023, the Notes due 2024, the 2024 Warrants, the Notes due 2025 and the 2025 Warrants. Certain common stock issuable under stock options, RSUs, PSUs, the Notes due 2026, the 2026 Warrants, the Notes due 2028 and the 2028 Warrants have been omitted from the diluted net income per share calculation because including such shares would have been antidilutive.

Diluted earnings per share for the year ended December 31, 2020 includes the dilutive effect of stock options, RSUs, PSUs, shares to be purchased under the ESPP, the Notes due 2023, the Notes due 2024 and the 2024 Warrants. Certain common stock issuable under stock options, RSUs, PSUs, Notes due 2025 and the 2025 Warrants have been omitted from the diluted net income per share calculation because including such shares would have been antidilutive.

Diluted earnings per share for the year ended December 31, 2019 includes the dilutive effect of stock options, RSUs, PSUs, shares to be purchased under the ESPP, the Notes due 2023 and Notes due 2024. Certain common stock issuable under stock options, RSUs, PSUs and warrants issued in conjunction with the Notes due 2024 have been omitted from the diluted net income per share calculation because including such shares would have been antidilutive.

Since the Company has the intent and ability to settle the aggregate principal amount of the Notes due 2025, Notes due 2026 and Notes due 2028 in cash and any excess in shares of the Company’s common stock, the Company uses the treasury stock method for calculating any potential dilutive effect of the conversion spread on diluted net income per share, if applicable. In order to compute the dilutive effect, the number of shares included in the denominator of diluted net income per share is determined by dividing the conversion spread value of the “in-the-money” Notes due 2025, Notes due 2026 and Notes due 2028 by the Company’s average share price during the period and including the resulting share amount in the diluted net income per share denominator. The conversion spread will have a dilutive impact on net income per share of common stock when the average market price of the Company’s common stock for a given period exceeds the conversion price of $81.54, $307.47 and $284.87 per share for the Notes due 2025, Notes due 2026 and Notes due 2028, respectively.

SEGMENT AND GEOGRAPHIC INFORMATION

12 Months Ended

Dec. 31, 2021

Segment Reporting [Abstract]

SEGMENT AND GEOGRAPHIC INFORMATION

The Company’s chief operating decision maker is the Chief Executive Officer. The Chief Executive Officer reviews financial information presented on a consolidated basis. The Company has one business activity, which entails the design, development, manufacture and sale of solutions for the solar PV industry. There are no segment managers who are held accountable for operations, operating results or plans for levels or components below the consolidated unit level. Accordingly, management has determined that the Company has a single operating and reportable segment.

See Note 3. “Revenue Recognition,” for the table presenting net revenues (based on the destination of shipments). The following table presents long-lived assets by geographic region as of and for the periods presented:

Long-Lived Assets


	December 31,
	2021		2020
	(In thousands)
United States	$	37,685	$	19,870
India	17,490		4,371
China	12,906		9,948
Mexico	8,735		4,808
New Zealand	4,622		3,837
Other	729		151
Total	$	82,167	$	42,985

- Definition

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

+ References

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+ Details

RELATED PARTY	12 Months Ended
RELATED PARTY	Dec. 31, 2021
Related Party Transactions [Abstract]
RELATED PARTY	RELATED PARTYIn 2018, a member of the Company’s board of directors and one of its principal stockholders, Thurman John Rodgers, purchased $5.0 million aggregate principal amount of the Notes due 2023 in a concurrent private placement. As of both December 31, 2021 and December 31, 2020, $5.0 million aggregate principal amount of the Notes due 2023 were outstanding. For additional information related to this purchase, see Note 13. “Debt,” for additional information related to this purchase.

SUBSEQUENT EVENTS	12 Months Ended
SUBSEQUENT EVENTS	Dec. 31, 2021
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	SUBSEQUENT EVENTS

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	Dec. 31, 2021
Accounting Policies [Abstract]
Basis of Presentation and Consolidation	Basis of Presentation and Consolidation The accompanying consolidated financial statements are presented in accordance with accounting principles generally accepted in the United States (“U.S.”), or GAAP. The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of income and expenses during the reporting period. Significant estimates and assumptions reflected in the financial statements include revenue recognition, allowance for doubtful accounts, stock-based compensation, deferred compensation arrangements, inventory valuation, accrued warranty obligations, fair value of investments, debt derivatives, convertible notes and contingent consideration, fair value of acquired intangible assets and goodwill, useful lives of acquired intangible assets and property and equipment, incremental borrowing rate for right-of-use assets and lease liability, legal contingencies, and tax valuation allowance. These estimates are based on information available as of the date of the financial statements; therefore, actual results could differ materially from those estimates due to risks and uncertainties, including uncertainty in the ongoing semiconductor supply and logistics constraints, and the evolving COVID-19 pandemic.
Revenue Recognition, Cost of Revenues and Contract Liabilities	Revenue Recognition The Company generates revenue from sales of its solutions, which include microinverter units and related accessories, an Envoy communications gateway, the cloud-based Enlighten monitoring service, storage solutions, Electric Vehicle (“EV”) charging solutions beginning in the first quarter of 2022, design, proposal and permitting services, as well as a platform matching cleantech asset owners to a local and on-demand workforce of service providers, to distributors, large installers, OEMs and strategic partners. Revenues are recognized when control of the promised goods or services are transferred to the Company’s customers in an amount that reflects the consideration that is expected to be received in exchange for those goods or services. The Company generates all of its revenues from contracts with its customers. A description of principal activities from which the Company generates revenues follows. •Products Delivered at a Point in Time. The Company sells its products and professional services to customers in accordance with the terms of the related customer contracts. The Company generates revenues from sales of its solutions, which include microinverter units and related accessories, an Envoy communications gateway and Enlighten service, communications accessories, storage solutions, EV charging solutions beginning in the first quarter of 2022, design, proposal and permitting services, as well as a platform matching cleantech asset owners to a local and on-demand workforce of service providers to distributors, large installers, OEMs and strategic partners. Microinverter units, microinverter accessories, storage and EV solutions, design, proposal and permitting services, as well as completed work orders on its platform matching cleantech asset owners to a local and on-demand workforce of service providers, are delivered to customers at a point in time, and the Company recognizes revenue for these products or professional services when the Company transfers control of the product or professional services to the customer, which is generally upon product shipment or service delivery, respectively. •Products Delivered Over Time. The sale of an Envoy communications gateway includes the Company’s Enlighten cloud-based monitoring service. The full consideration for these products represents a single performance obligation and is deferred at the sale date and recognized over the estimated service period of 6 years. The Company also sells certain communication accessories that contain a service performance obligation to be delivered over time. The revenue from these products is recognized over the related service period, which is typically 5 or 12 years. The subscription services revenue generated from each customer’s subscription to the Company’s design and proposal software is recognized on a ratable basis over the contract term beginning on the date that the Company’s service is made available to the customer. The subscription contracts are generally three to twelve months in length and billed in advance. When the Company sells a product with more than one performance obligation, such as the IQ Combiner which includes both hardware and Envoy, the total consideration is allocated to these performance obligations based on their relative standalone selling prices. The Company records certain contra revenue promotions as variable consideration and recognizes these promotions at the time the related revenue is recorded. The Company records upfront contract acquisition costs, such as sales commissions, to be capitalized and amortized over the estimated life of the asset. For contracts that have a duration of less than one year, the Company follows the Topic 606 practical expedient and expenses these costs when incurred. Commissions related to the Company’s sale of monitoring hardware and service are capitalized and amortized over the period of the associated revenue, which is 6 years. See Note 3 . “Revenue Recognition,” for additional information related to revenue recognition. Cost of Revenues The Company includes the following in cost of revenues: product costs, warranty, manufacturing personnel and logistics costs, freight costs, inventory write-downs, hosting services costs related to the Company’s Enlighten service offering and design and proposal services, depreciation and amortization of manufacturing test equipment and amortization of capitalized software development costs related to the Company’s Enlighten service offering, design and proposal services, and employee-related expenses associated with proposal and permitting services and design and proposal service customer support. A description of principal activities from which the Company recognizes cost of revenue is as follows. •Products Delivered at a Point in Time. Cost of revenue from these products is recognized when the Company transfers control of the product to the customer, which is generally upon shipment. •Products Delivered Over Time. Cost of revenue from these products is recognized over the related service period. Contract Liabilities Contract liabilities are recorded as deferred revenue on the accompanying consolidated balance sheets and include payments received in advance of performance obligations under the contract and are realized when the associated revenue is recognized under the contract.
Cash, Cash Equivalents and marketable Securities	Cash, Cash Equivalents and Marketable Securities The Company classifies investments in marketable securities as available-for-sale investments and records these marketable securities at fair value. The Company determines the appropriate classification of marketable securities at the time of purchase and reevaluates such designation at each balance sheet date. All highly liquid investments with original maturities of 90 days or less from the date of purchase are classified as cash equivalents, while all others are presented within current assets since these investments represent funds available for current operations and the Company has the ability and intent, if necessary, to liquidate any of these investments within one year in order to meet liquidity needs or to grow the business, including for potential business acquisitions or other strategic transactions. Marketable securities are recorded at fair value, with the unrealized gains or losses unrelated to credit loss factors included in accumulated other comprehensive income (loss), net of tax. Realized gains and losses and declines in value determined to be other than temporary based on the specific identification method are reported in other income (expense), net in the consolidated statements of operations. The Company periodically reviews whether the securities may be other-than-temporarily impaired, including whether or not (i) the Company has the intent to sell the security or (ii) it is more likely than not that the Company will be required to sell the security before its anticipated recovery. If one of these factors is met, the Company records an impairment loss associated with the impaired investment. The impairment loss will be recorded as a write-down of investments in the consolidated balance sheets and a realized loss within other income (expense), net in the consolidated statements of operations. There were no credit-related impairments recognized on the Company’s investments in marketable securities during the periods presented. For purposes of identifying and measuring impairment, the policy election was made to exclude the applicable accrued interest from both the fair value and amortized cost basis. Applicable accrued interest of $2.1 million, net of the allowance for credit losses, if any, is recorded in prepaid expenses and other current assets on the consolidated balance sheets as of December 31, 2021.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The fair value of a financial instrument is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The carrying amounts of the Company’s cash and cash equivalents, accounts receivable, accounts payable and accrued liabilities approximate fair value because of the short maturity of those instruments. Equity investments with readily determinable fair value are carried at fair value based on quoted market prices or estimated based on market conditions and risks existing at each balance sheet date. Equity investments without readily determinable fair value are measured at cost less impairment, and are adjusted for observable price changes in orderly transactions for an identical or similar investment of the same issuer.
Accounts Receivables and Contract Assets	Accounts Receivables and Contract Assets The Company receives payments from customers based upon contractual billing schedules. Accounts receivable are recorded when the right to consideration becomes unconditional. Contract assets include deferred product costs and commissions associated with the deferred revenue and will be amortized along with the associated revenue.
Allowance for Doubtful Accounts	Allowance for Doubtful AccountsThe Company maintains allowances for doubtful accounts for uncollectible accounts receivable. Management estimates anticipated credit losses from doubtful accounts based on days past due, customer specific experience, collection history, the financial health of customers including from the impacts of the COVID-19 pandemic, among other factors. Accounts receivable are recorded net of allowance for doubtful accounts.
Inventory	Inventory Inventory is valued at the lower of cost or market. Market is current replacement cost (by purchase or by reproduction, dependent on the type of inventory). In cases where market exceeds net realizable value (i.e., estimated selling price less reasonably predictable costs of completion and disposal), inventories are stated at net realizable value. Market is not considered to be less than net realizable value reduced by an allowance for an approximately normal profit margin. The Company determines cost on a first-in first-out basis. Management assesses the valuation on a quarterly basis and writes down the value for any excess and obsolete inventory based upon expected demand, anticipated sales price, effect of new product introductions, product obsolescence, customer concentrations, product merchantability and other factors. Inventory write-downs are equal to the difference between the cost of inventories and market.
Long-Lived Assets	Long-Lived Assets Property and equipment are stated at cost less accumulated depreciation. Cost includes amounts paid to acquire or construct the asset as well as any expenditure that substantially adds to the value of or significantly extends the useful life of an existing asset. Repair and maintenance costs are expensed as incurred. Depreciation and amortization are computed using the straight-line method over the estimated useful lives of the assets, which range from 3 to 10 years. Leasehold improvements are amortized over the shorter of the lease term or expected useful life of the improvements.
Internal-Use Software	Internal-use software, whether purchased or developed, is capitalized at cost and amortized on a straight-line basis over its estimated useful life. Costs associated with internally developed software are expensed until the point at which the project has reached the development stage. Subsequent additions, modifications or upgrades to internal-use software are capitalized only to the extent that they provide additional functionality. Software maintenance and training costs are expensed in the period in which they are incurred. The capitalization of internal-use software requires judgment in determining when a project has reached the development stage and the period over which the Company expects to benefit from the use of that software. The Company capitalizes implementation costs related to cloud computing (i.e. hosting) arrangements that are accounted for as a service contract that meets the accounting requirement for capitalization as such implementation costs were incurred to develop or utilize internal-use software hosted by a third party vendor. The capitalized implementation costs are recorded as part of “Other assets” on the consolidated balance sheet and is amortized over the length of the service contract.
Impairment of Long-Lived Assets	Property, plant and equipment, including internal-use software, and capitalized implementation costs related to cloud computing arrangements, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset (asset group) may not be recoverable. An impairment loss would be recognized when the carrying amount of an asset exceeds the estimated undiscounted future cash flows expected to result from the use of the asset and its eventual disposition. The amount of the impairment loss to be recorded is calculated by the excess of the asset’s carrying value over its fair value. Fair value is generally determined using a discounted cash flow analysis.
Business Combinations	Business Combinations Assets acquired and liabilities assumed as part of a business acquisition are generally recorded at their fair value at the date of acquisition. The excess of purchase price over the fair value of assets acquired and liabilities assumed is recorded as goodwill. Determining fair value of identifiable assets, particularly intangibles, and liabilities acquired also requires the Company to make estimates, which are based on all available information and in some cases assumptions with respect to the timing and amount of future revenues and expenses associated with an asset. Accounting for business acquisitions requires the Company to make judgments as to whether a purchase transaction is a multiple element contract, meaning that it includes other transaction components. This judgment and determination affect the amount of consideration paid that is allocable to assets and liabilities acquired in the business purchase transaction. Additional information existing as of the acquisition date but unknown to the Company may become known during the remainder of the measurement period, not to exceed 12 months from the acquisition date, which may result in changes to the amounts and allocations recorded.
Goodwill and Intangible Assets	Goodwill Goodwill results from the purchase consideration paid in excess of the fair value of the net assets recorded in connection with business acquisitions. Goodwill is not amortized but is assessed for potential impairment at least annually during the fourth quarter of each fiscal year or between annual tests if an event occurs or circumstances change that would indicate the carrying amount may be impaired. Goodwill is tested at the reporting unit level, which the Company has determined to be the same as the entity as a whole (entity level). The Company first performs qualitative assessment to determine whether it is more likely than not that the fair value of our reporting unit is less than its carrying value. If, after assessing the qualitative factors, we determine that it is more likely than not that the fair value of our reporting unit is less than its carrying value, an impairment analysis will be performed. Qualitative factors include industry and market consideration, overall financial performance, share price trends and market capitalization and Company-specific events. The Company determined, after performing a qualitative review of its reporting unit, that it is more likely than not that the fair value of our reporting unit exceeds its carrying value. Accordingly, there was no indication of impairment in the years ended 2021, 2020 and 2019 and no quantitative goodwill impairment test was performed. Intangible Assets Intangible assets include patents and other purchased intangible assets. Intangible assets with finite lives are amortized on a straight-line basis, with estimated useful lives ranging from 5 to 9 years. Indefinite-lived intangible assets are tested for impairment annually and are also tested for impairment between annual tests if an event occurs or circumstances change that would indicate that the carrying amount may be impaired. Intangible assets with finite lives are tested for impairment whenever events or circumstances indicate that the carrying amount of an asset (asset group) may not be recoverable. An impairment loss is recognized when the carrying amount of an asset exceeds the estimated undiscounted cash flows used in determining the fair value of the asset. The amount of the impairment loss to be recorded is calculated by the excess of the asset’s carrying value over its fair value. Fair value is generally determined using a discounted cash flow analysis. There was no impairment of intangible assets in any of the years presented.
Warranty Obligations	Warranty Obligations Microinverters and Other Products Sold Through December 31, 2013 The Company’s warranty accrual provides for the replacement of microinverter units or other products that fail during the product’s warranty term (typically 15 years for first and second generation microinverters and up to 25 years for subsequent generation microinverters). On a quarterly basis, the Company employs a consistent, systematic and rational methodology to assess the adequacy of its warranty liability. This assessment includes updating all key estimates and assumptions for each generation of product, based on historical results, trends and the most current data available as of the filing date. The key estimates and assumptions used in the warranty liability are thoroughly reviewed by management on a quarterly basis. The key estimates used by the Company to estimate its warranty liability are: (1) the number of units expected to fail over time (i.e., failure rate); (2) the number of failed units expected to result in warranty claims over time (i.e., claim rate); and (3) the per unit cost of replacement units, including outbound shipping and limited labor costs, expected to be incurred to replace failed units over time (i.e., replacement cost). Estimated Failure Rates — The Company’s Quality and Reliability department has primary responsibility to determine the estimated failure rates for each generation of microinverter. To establish initial failure rate estimates for each generation of microinverter, the Company’s quality engineers use a combination of industry standard Mean Time Between Failure (“MTBF”) estimates for individual components contained in its microinverters, third party data collected on similar equipment deployed in outdoor environments similar to those in which the Company’s microinverters are installed, and rigorous long term reliability and accelerated life cycle testing which simulates the service life of the microinverter in a short period of time. As units are deployed into operating environments, the Company continues to monitor product performance through its Enlighten monitoring platform. It typically takes three to nine months between the date of sale and date of end-user installation. Consequently, the Company’s ability to monitor actual failures of units sold similarly lags by three to nine months. When a microinverter fails and is returned, the Company performs diagnostic root cause failure analysis to understand and isolate the underlying mechanism(s) causing the failure. The Company then uses the results of this analysis (combined with the actual, cumulative performance data collected on those units prior to failure through Enlighten) to draw conclusions with respect to how or if the identified failure mechanism(s) will impact the remaining units deployed in the installed base. Estimated Claim Rates — Warranty claim rate estimates are based upon observed historical trends and assumptions with respect to expected customer behavior over the warranty period. As the vast majority of the Company’s microinverters have been sold to end users for residential applications, the Company believes that warranty claim rates will be affected by changes over time in residential home ownership because the Company expects that subsequent homeowners are less likely to file claims than the homeowners who originally purchase the microinverters. Estimated Replacement Costs — Three factors are considered in the Company’s analysis of estimated replacement cost: (1) the estimated cost of replacement microinverters; (2) the estimated cost to ship replacement microinverters to end users; and (3) the estimated labor reimbursement expected to be paid to third party installers performing replacement services for the end user. Because the Company’s warranty provides for the replacement of defective microinverters over long periods of time (between 15 and 25 years, depending on the generation of product purchased), the estimated per unit cost of current and future product generations is considered in the estimated replacement cost. Estimated costs to ship replacement units are based on observable, market-based shipping costs paid by the Company to third party freight carriers. The Company has a separate program that allows third-party installers to claim fixed-dollar reimbursements for labor costs they incur to replace failed microinverter units for a limited time from the date of original installation. Included in the Company’s estimated replacement cost is an analysis of the number of fixed-dollar labor reimbursements expected to be claimed by third party installers over the limited offering period. In addition to the key estimates noted above, the Company also compares actual warranty results to expected results and evaluates any significant differences. Management may make additional adjustments to the warranty provision based on performance trends or other qualitative factors. If actual failure rates, claim rates, or replacement costs differ from the Company’s estimates in future periods, changes to these estimates may be required, resulting in increases or decreases in the Company’s warranty obligations. Such increases or decreases could be material. Fair Value Option for Microinverters and Other Products Sold Since January 1, 2014 The Company’s warranty obligations related to microinverters sold since January 1, 2014 provide the Company the right, but not the requirement, to assign its warranty obligations to a third-party. Under Accounting Standards Codification (“ASC”) 825, “Financial Instruments” (also referred to as “fair value option”), an entity may choose to elect the fair value option for such warranties at the time it first recognizes the eligible item. The Company made an irrevocable election to account for all eligible warranty obligations associated with microinverters sold since January 1, 2014 at fair value. This election was made to reflect the underlying economics of the time value of money for an obligation that will be settled over an extended period of up to 25 years. The Company estimates the fair value of warranty obligations by calculating the warranty obligations in the same manner as for sales prior to January 1, 2014 and applying an expected present value technique to that result. The expected present value technique, an income approach, converts future amounts into a single current discounted amount. In addition to the key estimates of failure rates, claim rates and replacement costs, the Company used certain inputs that are unobservable and significant to the overall fair value measurement. Such additional assumptions included compensation comprised of a profit element and risk premium required of a market participant to assume the obligation and a discount rate based on the Company’s credit-adjusted risk-free rate. See Note 11. “Fair Value Measurements,” for additional information. Warranty obligations initially recorded at fair value at the time of sale will be subsequently re-measured to fair value at each reporting date. In addition, the fair value of the liability will be accreted over the corresponding term of the warranty of up to 25 years using the interest method. Warranty for Other Products The Company offers a 5‑year warranty for its Envoy communications gateway and a 10‑year warranty on its AC Battery storage solution. The warranties provide the Company with the right, but not the obligation, to assign its warranty obligations to a third-party. As such, warranties for Envoy and AC Battery storage solution products are accounted for under the fair value method of accounting.
Commitments and Contingencies	Commitments and Contingencies In the normal course of business, the Company is subject to loss contingencies and loss recoveries, such as legal proceedings and claims arising out of its business as well as tariff refunds. An accrual for a loss contingency or loss recovery is recognized when it is probable and the amount of loss or recovery can be reasonably estimated.
Advertising Costs	Advertising Costs Advertising costs, which are expensed and included in sales and marketing expense when incurred, were $16.2 million, $0.8 million and $0.6 million during the years ended December 31, 2021, 2020 and 2019, respectively.
Research and Development Costs	Research and Development Costs The Company expenses research and development costs as incurred. Research and development expense consists primarily of product development personnel costs, including salaries and benefits, stock-based compensation, other professional costs and allocated facilities costs.
Stock-Based Compensation	Stock-Based Compensation Share-based payments are required to be recognized in the Company’s consolidated statements of operations based on their fair values and the estimated number of shares expected to vest. The Company measures stock-based compensation expense for all share-based payment awards, including stock options made to employees and directors, based on the estimated fair values on the date of the grant. The fair value of stock options granted is estimated using the Black-Scholes option valuation model. The fair value of restricted stock units granted is determined based on the price of the Company’s common stock on the date of grant. The fair value of non-market‑based performance stock units granted is determined based on the date of grant or when achievement of performance is probable. The fair value of market‑based performance stock units granted is determined using a Monte‑Carlo model based on the date of grant or when achievement of performance is probable. Stock-based compensation for stock options and restricted stock units (“RSUs”) is recognized on a straight-line basis over the requisite service period. Stock-based compensation for performance stock units (“PSUs”) without market conditions is recognized when the performance condition is probable of being achieved, and then on a graded basis over the requisite service period. Stock-based compensation for PSUs with market conditions is recognized on a straight-line basis over the requisite service period. Additionally, the Company estimates its forfeiture rate annually based on historical experience and revise the estimates of forfeiture in subsequent periods if actual forfeitures differ from those estimates.
Common Stock Repurchase	Common Stock Repurchase The Company accounts for repurchase of common stock under ASC 505 and charges the entire cost of repurchase to the accumulated deficit.
Leases	Leases The Company determines if an arrangement is or contains a lease at inception. Operating lease assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments over the lease term. Operating lease assets and liabilities are recognized based on the present value of the remaining lease payments discounted using the Company’s incremental borrowing rate. Operating lease assets also include initial direct costs incurred and prepaid lease payments, minus any lease incentives. The Company’s lease terms include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Lease expense is recognized on a straight-line basis over the lease term. The Company combines the lease and non-lease components in determining the operating lease assets and liabilities.
Foreign Currency Translation	Foreign Currency Translation The Company and most of its subsidiaries use their respective local currency as their functional currency. Accordingly, foreign currency assets and liabilities are translated using exchange rates in effect at the end of the period. Aggregate exchange gains and losses arising from the translation of foreign assets and liabilities are included in accumulated other comprehensive income (loss) in stockholders' equity. Foreign subsidiaries that use the U.S. dollar as their functional currency remeasure monetary assets and liabilities using exchange rates in effect at the end of the period. In addition, transactions that are denominated in non-functional currency are remeasured using exchange rates in effect at the end of the period. Exchange gains and losses arising from the remeasurement of monetary assets and liabilities are included in other income (expense), net in the consolidated statements of operations. Non-monetary assets and liabilities are carried at their historical values.
Comprehensive Income (Loss)	Comprehensive Income (Loss) Comprehensive income (loss) consists of two components, net income (loss) and other comprehensive income (loss). Other comprehensive income (loss) refers to gains and losses that are recorded as an element of stockholders’ equity but are excluded from net income (loss). The Company’s other comprehensive income (loss) consists of foreign currency translation adjustments and change in net unrealized gain (loss) on marketable securities, net of tax.
Income Taxes	Income Taxes The Company records income taxes using the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected tax consequences of temporary differences between the tax bases of assets and liabilities for financial reporting purposes and amounts recognized for income tax purposes. In estimating future tax consequences, generally all expected future events other than enactments or changes in the tax law or rates are considered. Valuation allowances are provided when necessary to reduce deferred tax assets to the amount expected to be realized. The Company assesses the realizability of the deferred tax assets to determine release of valuation allowance as necessary. In the event the Company determines that it is more likely than not that we would be able to realize deferred tax assets in the future in excess of our net recorded amount, an adjustment to the valuation allowance for the deferred tax asset would increase income in the period such determination was made. Likewise, should it be determined that additional amounts of the net deferred tax asset will not be realized in the future, an adjustment to increase the deferred tax asset valuation allowance will be charged to income in the period such determination is made. The Company operates in various tax jurisdictions and is subject to audit by various tax authorities. The Company follows accounting for uncertainty in income taxes which requires that the tax effects of a position be recognized only if it is “more likely than not” to be sustained based solely on its technical merits as of the reporting date. The Company considers many factors when evaluating and estimating its tax positions and tax benefits, which may require periodic adjustments and which may not accurately anticipate actual outcomes.
Recently Issued Accounting Pronouncements Not Yet Effective	Recently Issued Accounting Pronouncements Not Yet Effective In August 2020, the FASB issued Accounting Standards Update (“ASU”) 2020-06, “Debt - Debt with Conversion and Other Options (subtopic 470-20) and Derivatives and Hedging - Contracts in Entity’s Own Equity (subtopic 815-40),” which reduces the number of accounting models in ASC 470-20 that require separate accounting for embedded conversion features. As a result, a convertible debt instrument will be accounted for as a single liability measured at its amortized cost as long as no other features require bifurcation and recognition as derivatives. By removing those separation models, the effective interest rate of convertible debt instruments will be closer to the coupon interest rate. Further, the diluted net income per share calculation for convertible instruments will require the Company to use the if-converted method. The treasury stock method should no longer be used to calculate diluted net income per share for convertible instruments. The Company will adopt the new guidance in the annual period beginning January 1, 2022, on a modified retrospective basis. On the date of adoption, the Company expects to record a net decrease to additional paid-in capital by approximately $207.9 million, net of tax to remove the equity component separately recorded for the conversion features associated with the convertible debt instruments and equity component associated with the issuance costs, an increase of approximately $244.5 million in the carrying value of its convertible debt instrument to reflect the full principal amount of the Notes outstanding net of issuance costs, a decrease to deferred tax liability of approximately $62.3 million, and a decrease of approximately $25.7 million, net of tax to accumulated deficit. These estimates could change as the Company continues to progress with the implementation of the standard. In October 2021, the FASB issued ASU 2021-08, "Business Combinations (Topic 805): Accounting for Contract Assets and Contract Liabilities from Contracts with Customers" (“ASU 2021-08”). The standard requires an acquirer in a business combination to recognize and measure contract assets and contract liabilities acquired in a business combination in accordance with ASC 606, Revenue from Contracts with Customers, as if it had originated the contracts. The standard is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2022. Early adoption is permitted. The Company does not expect the adoption of ASU 2021-08 to have a significant impact on its consolidated financial statements and plans to adopt the standard effective January 1, 2023.
Fair Value Measurement	The accounting guidance defines fair value as the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. When determining the fair value measurements for assets and liabilities recorded at fair value, the Company considers the principal or most advantageous market in which it would transact and considers assumptions that market participants would use when pricing the asset or liability, such as inherent risk, transfer restrictions, and risk of nonperformance. The fair value hierarchy requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. An asset’s or liability’s categorization within the fair value hierarchy is based upon the lowest level of input that is significant to the fair value measurement. Three levels of inputs may be used to measure fair value: •Level 1 - Valuations based on quoted prices in active markets for identical assets or liabilities that the Company is able to access. Since valuations are based on quoted prices that are readily and regularly available in an active market, valuation of such assets or liabilities do not entail a significant degree of judgment. •Level 2 - Valuations based on one or more quoted prices in markets that are not active or for which all significant inputs are observable, either directly or indirectly. •Level 3 - Valuations based on inputs that are unobservable and significant to the overall fair value measurement.
Earnings Per Share	Basic net income per share is computed by dividing net income by the weighted average number of shares of common stock outstanding during the period. Diluted net income per share is computed in a similar manner, but it also includes the effect of potential common shares outstanding during the period, when dilutive. Potential common shares include Stock Options, RSUs, PSUs, shares to be purchased under the Company’s ESPP, the Notes due 2023, Notes due 2024, Notes due 2025, Notes due 2026, Notes due 2028, 2024 Warrants, 2025 Warrants, 2026 Warrants, and the 2028 Warrants. See Note 13. “Debt,” of the notes to the consolidated financial statements included in Part II, Item 8 of this Annual Report on Form 10-K for additional information. The dilutive effect of potentially dilutive common shares is reflected in diluted earnings per share by application of the treasury stock method for stock options, RSUs, PSUs, the Notes due 2024, the Notes due 2025, the Notes due 2026, the Notes due 2028, the 2024 Warrants, the 2025 Warrants, the 2026 Warrants and the 2028 Warrants. To the extent these potential common shares are antidilutive, they are excluded from the calculation of diluted net income per share.

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)

12 Months Ended

Dec. 31, 2021

Accounting Policies [Abstract]

Schedule of Activity in Allowance for Doubtful Accounts

The following table sets forth activities in the allowance for doubtful accounts for the periods indicated.


	December 31,
	2021		2020		2019
	(In thousands)
Balance, at beginning of year	$	462	$	564	$	2,138
Net charges to expense or reduction in revenue	1,140		425		217
Write-offs, net of recoveries	(12)		(527)		(1,791)
Balance, at end of year	$	1,590	$	462	$	564

REVENUE RECOGNITION (Tables)

12 Months Ended

Dec. 31, 2021

Revenue from Contract with Customer [Abstract]

Summary of Revenue Disaggregation

Disaggregated revenue by primary geographical market and timing of revenue recognition for the Company’s single product line are as follows:


	Years Ended December 31,
		2021		2020
		(In thousands)
Primary geographical markets:
U.S.		$	1,108,801	$	637,879




International		273,248		136,546
Total		$	1,382,049	$	774,425

Timing of revenue recognition:
Products delivered at a point in time		$	1,323,960	$	728,254
Products and services delivered over time		58,089		46,171
Total		$	1,382,049	$	774,425

Summary of Contract Assets and Contract Liabilities, and Changes in Balances from Contracts with Customers

Receivables, and contract assets and contract liabilities from contracts with customers are as follows:


	December 31, 2021		December 31, 2020
	(In thousands)
Receivables	$	333,626	$	182,165

Short-term contract assets (Prepaid expenses and other assets)	23,508		17,879
Long-term contract assets (Other assets)	69,583		51,986



Short-term contract liabilities (Deferred revenues, current)	62,670		47,665
Long-term contract liabilities (Deferred revenues, non-current)	187,186		125,473

Significant changes in the balances of contract assets (prepaid expenses and other assets) as of December 31, 2021 are as follows (in thousands):


Contract Assets
Contract Assets, beginning of period	$	69,865
Amount recognized	(21,894)
Increase	45,120
Contract Assets, end of period	$	93,091

Significant changes in the balances of contract liabilities (deferred revenues) as of December 31, 2021 are as follows (in thousands):


Contract Liabilities
Contract Liabilities, beginning of period	$	173,138
Revenue recognized	(64,793)

Increase due to billings	141,511

Contract Liabilities, end of period	$	249,856

Summary of Estimated Revenue Expected to be Recognized in Future Periods

Estimated revenue expected to be recognized in future periods related to performance obligations that are unsatisfied or partially unsatisfied at the end of the reporting period are as follows:


	December 31, 2021
	(In thousands)
Fiscal year:
2022	$	62,671
2023	55,497
2024	50,300
2025	43,362
2026	27,607
Thereafter	10,419
Total	$	249,856

INVENTORY (Tables)

12 Months Ended

Dec. 31, 2021

Inventory Disclosure [Abstract]

Summary of Inventory

Inventory consists of the following:



	December 31, 2021		December 31, 2020
	(In thousands)
Raw materials	$	25,429	$	10,140
Finished goods	48,971		31,624
Total inventory	$	74,400	$	41,764

PROPERTY AND EQUIPMENT, NET (Tables)

12 Months Ended

Dec. 31, 2021

Property, Plant and Equipment [Abstract]

Summary of Property and Equipment

Property and equipment consist of the following:


	Estimated Useful Life	December 31,
		2021		2020
	(Years)	(In thousands)
Equipment and machinery	3-10	$	95,365	$	63,411
Furniture and fixtures	5-10	3,197		2,532
Computer equipment	3-5	5,861		2,972
Capitalized software costs	3-5	28,118		17,004
Building and leasehold improvements	3-10	12,546		9,021
Land		114		—
Construction in process		14,332		9,747
Total		159,533		104,687
Less accumulated depreciation and amortization		(77,366)		(61,702)
Property and equipment, net		$	82,167	$	42,985

BUSINESS COMBINATION (Tables)

12 Months Ended

Dec. 31, 2021

Business Combination and Asset Acquisition [Abstract]

Summary of fair values of assets acquired and liabilities assumed


Net tangible assets acquired	$	8,387
Intangible assets	37,800

Goodwill	66,916
Net assets acquired	$	113,103


Net tangible assets acquired	$	38
Intangible assets	19,500
Deferred tax liabilities	(2,906)
Goodwill	53,280
Net assets acquired	$	69,912

The following table summarizes the fair values of the assets acquired and liabilities assumed at the acquisition date (in thousands):


Net tangible assets acquired	$	1,281
Intangible assets	11,700
Goodwill	11,804
Net assets acquired	$	24,785

The following table summarizes the fair values of the assets acquired and liabilities assumed at the acquisition date, (in thousands):


Net tangible assets acquired	$	1,441
Intangible assets	9,200
Deferred tax asset	457
Goodwill	24,390
Net assets acquired	$	35,488

Summary of intangible assets acquired

The following table shows the fair value of the separately identifiable intangible assets at the time of acquisition and the period over which each intangible asset will be amortized:


	Preliminary Fair Value		Useful Life
	(In thousands)		(Years)
Order backlog	$	600	Based on actual shipments
Trade name	37,200		5
Total identifiable intangible assets	$	37,800

The following table shows the fair value of the separately identifiable intangible assets at the time of acquisition and the period over which each intangible asset will be amortized:


	Preliminary Fair Value		Useful Life
	(In thousands)		(Years)
Developed technology	$	18,400	5
Customer relationship	1,100		5
Total identifiable intangible assets	$	19,500

The following table shows the fair value of the separately identifiable intangible assets at the time of acquisition and the period over which each intangible asset will be amortized:

Preliminary Fair Value

Useful Life

(In thousands)

(Years)

Customer relationship

11,700

The following table shows the fair value of the separately identifiable intangible assets at the time of acquisition and the period over which each intangible asset will be amortized:


	Preliminary Fair Value		Useful Life
	(In thousands)		(Years)
Developed technology	$	6,900	5
Customer relationship	1,800		5
Trade name	500		5
Total identifiable intangible assets	$	9,200

Business Acquisition, Pro Forma Information


	Years Ended December 31,
		2021		2020
Net revenues		$	1,401,803	$	790,791
Net income		$	145,798	$	139,126

Summary of consideration transferred for business acquisition

The acquisition date fair value of the purchase price was approximately $35.5 million, which consisted of the following (in thousands):


Cash consideration	$	31,988
Fair value of contingent consideration	3,500
Total	$	35,488

GOODWILL AND INTANGIBLE ASSETS (Tables)

12 Months Ended

Dec. 31, 2021

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Goodwill

The Company’s goodwill as of December 31, 2021 and December 31, 2020 are as follows:


Goodwill	December 31, 2021		December 31, 2020
	(In thousands)
Goodwill, beginning of period	$	24,783	$	24,783
Goodwill acquired	156,390		—
Currency translation adjustment	81		—
Goodwill, end of period	$	181,254	$	24,783

Schedule of Acquired Indefinite-lived Intangible Assets by Major Class

The Company’s purchased intangible assets as of December 31, 2021 and December 31, 2020 are as follows:


	December 31, 2021								December 31, 2020
	Gross		Additions		Accumulated Amortization		Net		Gross		Additions		Accumulated Amortization		Net
	(In thousands)


Intangible assets:
Other indefinite-lived intangibles	$	286	$	—	$	—	$	286	$	286	$	—	$	—	$	286

Intangible assets with finite lives:

Developed technology	13,100		25,550		(8,958)		29,692		13,100		—		(5,276)		7,824
Customer relationships	26,421		14,600		(11,448)		29,573		23,100		3,321		(5,723)		20,698
Trade names	—		37,700		(93)		37,607		—		—		—		—
Order backlog	—		600		—		600		—		—		—		—
Total purchased intangible assets	$	39,807	$	78,450	$	(20,499)	$	97,758	$	36,486	$	3,321	$	(10,999)	$	28,808

Schedule of Acquired Finite-Lived Intangible Assets by Major Class

The Company’s purchased intangible assets as of December 31, 2021 and December 31, 2020 are as follows:


	December 31, 2021								December 31, 2020
	Gross		Additions		Accumulated Amortization		Net		Gross		Additions		Accumulated Amortization		Net
	(In thousands)


Intangible assets:
Other indefinite-lived intangibles	$	286	$	—	$	—	$	286	$	286	$	—	$	—	$	286

Intangible assets with finite lives:

Developed technology	13,100		25,550		(8,958)		29,692		13,100		—		(5,276)		7,824
Customer relationships	26,421		14,600		(11,448)		29,573		23,100		3,321		(5,723)		20,698
Trade names	—		37,700		(93)		37,607		—		—		—		—
Order backlog	—		600		—		600		—		—		—		—
Total purchased intangible assets	$	39,807	$	78,450	$	(20,499)	$	97,758	$	36,486	$	3,321	$	(10,999)	$	28,808

Schedule of Amortization Expense

Amortization expense related to finite-lived intangible assets are as follows:


	Years Ended December 31,
		2021		2020
		(In thousands)
Developed technology		$	3,681	$	2,183
Customer relationships		5,726		2,909

Trade names		93		—
Total amortization expense		$	9,500	$	5,092

The expected future annual amortization expense of intangible assets as of December 31, 2021 is presented below (in thousands):


	December 31, 2021

Fiscal year:
2022	$	22,212
2023	21,856
2024	19,059
2025	17,744
2026	14,185
Thereafter	2,416
Total	$	97,472

CASH EQUIVALENTS AND MARKETABLE SECURITIES (Tables)

12 Months Ended

Dec. 31, 2021

Cash and Cash Equivalents [Abstract]

Debt Securities, Available-for-sale

The marketable securities consist of the following (in thousands):


	As of December 31, 2021
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value		Cash and Cash Equivalents		Marketable Securities
Money market funds	$	35,789	$	—	$	—	$	35,789	$	35,789	$	—
Certificate of Deposit	16,001		—		(2)		15,999		6,000		9,999
Commercial paper	215,964		—		(114)		215,850		26,997		188,853
Corporate notes and bonds	199,244		—		(872)		198,372		760		197,612
U.S. Treasuries	14,999		—		(1)		14,998		—		14,998
U.S. Government agency securities	487,743		—		(1,870)		485,873		—		485,873
Total	$	969,740	$	—	$	(2,859)	$	966,881	$	69,546	$	897,335

Investments Classified by Contractual Maturity Date

The following table summarizes the contractual maturities of the Company’s marketable securities as of December 31, 2021 (in thousands):


	Amortized Cost		Fair Value
Due within one year	$	533,237	$	532,689
Due within one to three years	436,503		434,192
Total	$	969,740	$	966,881

ACCRUED LIABILITIES (Tables)

12 Months Ended

Dec. 31, 2021

Payables and Accruals [Abstract]

Schedule of Accrued Liabilities

Accrued liabilities consist of the following:


	December 31, 2021		December 31, 2020
	(In thousands)
Salaries, commissions, incentive compensation and benefits	$	13,062	$	6,634
Customer rebates and sales incentives	79,038		36,622
Freight	20,522		10,300
Operating lease liabilities, current	3,830		4,542
Liability due to supply agreements	14,653		5,500
Contingent consideration	3,710		—
Post combination expense accrual	8,602		—

Other	14,495		12,944
Total accrued liabilities	$	157,912	$	76,542

WARRANTY OBLIGATIONS (Tables)

12 Months Ended

Dec. 31, 2021

Product Warranties Disclosures [Abstract]

Summary of Warranty Activities

The Company’s warranty activities were as follows:


	Years Ended December 31,
		2021		2020		2019
		(In thousands)
Warranty obligations, beginning of period		$	45,913	$	37,098	$	31,294
Accruals for warranties issued during period		18,098		7,021		5,244

Changes in estimates		19,414		9,954		8,591
Settlements		(15,073)		(12,811)		(10,881)
Increase due to accretion expense		4,654		3,255		2,326

Other		371		1,396		524
Warranty obligations, end of period		73,377		45,913		37,098
Less: current portion		(19,395)		(11,260)		(10,078)
Non-current		$	53,982	$	34,653	$	27,020

FAIR VALUE MEASUREMENTS (Tables)

12 Months Ended

Dec. 31, 2021

Fair Value Disclosures [Abstract]

Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis

The following table presents assets and liabilities measured at fair value on a recurring basis using the above input categories:


	December 31, 2021						December 31, 2020
	(In thousands)
	Level 1		Level 2		Level 3		Level 1		Level 2		Level 3
Assets:
Cash and cash equivalents:
Money market funds	$	35,789	$	—	$	—	$	654,699	$	—	$	—
Certificate of deposit	—		6,000		—		—		—		—
Commercial paper	—		26,997		—		—		—		—
Corporate notes and bonds	—		760		—		—		—		—

Marketable securities:
Certificate of deposit	—		9,999		—		—		—		—
Commercial paper	—		188,853		—		—		—		—
Corporate notes and bonds	—		197,612		—		—		—		—
U.S. Government agencies	—		485,873		—		—		—		—
U.S. Treasuries	—		14,998		—		—		—		—
Other assets
Investments in debt securities	—		—		41,042		—		—		—

Total assets measured at fair value	$	35,789	$	931,092	$	41,042	$	654,699	$	—	$	—

Liabilities:
Accrued liabilities
Contingent consideration	$	—	$	—	$	3,710	$	—	$	—	$	—
Warranty obligations
Current	—		—		14,612		—		—		8,267
Non-current	—		—		36,395		—		—		20,469
Total warranty obligations measured at fair value	—		—		51,007		—		—		28,736
Total liabilities measured at fair value	$	—	$	—	$	54,717	$	—	$	—	$	28,736

Summary of Significant Unobservable Inputs used in the Fair Value Measurement of Assets Designated as Level 3

The changes in the balance in investments in debt securities during the period are as follows:


	Year Ended December 31,
		2021
		(In thousands)
Balance at beginning of period		$	—
Investment		58,000
Fair value adjustments included in other (expense) income, net		9,611
Settlement		(26,569)
Balance at end of period		$	41,042

Schedule of Changes in Nonfinancial Liabilities Related to Warrant Obligations Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs

The following table reflects the activity for the Company’s contingent consideration liabilities measured at fair value using Level 3 inputs for the year ended December 31, 2021:


	Year Ended December 31,
		2021
		(In thousands)
Balance at beginning of period		$	—
Addition		3,500
Fair value adjustments included in other income (expense), net		210
Balance at end of period		$	3,710


	Years Ended December 31,
		2021		2020
		(In thousands)
Balance at beginning of period		$	28,736	$	19,806
Accruals for warranties issued during period		18,098		7,021
Changes in estimates		10,844		5,039
Settlements		(11,248)		(7,781)
Increase due to accretion expense		4,654		3,255
Other		(77)		1,396
Balance at end of period		$	51,007	$	28,736

Summary of Significant Unobservable Inputs used in the Fair Value Measurement of Liabilities Designated as Level 3

As of December 31, 2021 and December 31, 2020, the significant unobservable inputs used in the fair value measurement of the Company’s liabilities designated as Level 3 are as follows:

Percent Used

(Weighted Average)

Item Measured at Fair Value

Valuation Technique

Description of Significant Unobservable Input

December 31,
2021

December 31,
2020

Warranty obligations for microinverters sold since January 1, 2014

Discounted cash flows

Profit element and risk premium

15%

Credit-adjusted risk-free rate

12%

13%

RESTRUCTURING (Tables)

12 Months Ended

Dec. 31, 2021

Restructuring and Related Activities [Abstract]

Restructuring and Related Costs

Restructuring expense consist of the following:


	Years Ended December 31,
		2021		2020		2019
		(In thousands)
Redundancy and employee severance and benefit arrangements		$	—	$	—	$	1,575
Asset impairments		—		—		1,124

Lease loss reserves (benefit)		—		—		(100)

Total restructuring charges		$	—	$	—	$	2,599

The following table presents the details of the Company’s restructuring charges under the 2018 Plan for the period indicated:


	Years Ended December 31,
		2021		2020		2019
		(In thousands)
Redundancy and employee severance and benefit arrangements		$	—	$	—	$	1,575
Asset impairments		—		—		1,124

Lease loss reserves (benefit)		—		—		(100)

Total restructuring charges		$	—	$	—	$	2,599

DEBT (Tables)

12 Months Ended

Dec. 31, 2021

Debt Disclosure [Abstract]

Schedule of Debt

The following table provides information regarding the Company’s debt.


	December 31, 2021		December 31, 2020
	(In thousands)
Convertible notes
Notes due 2028	$	575,000	$	—
Less: unamortized discount and issuance costs	(149,411)		—
Carrying amount of Notes due 2028	425,589		—

Notes due 2026	632,500		—
Less: unamortized discount and issuance costs	(111,433)		—
Carrying amount of Notes due 2026	521,067		—

Notes due 2025	102,175		320,000
Less: unamortized discount and issuance costs	(16,123)		(64,979)
Carrying amount of Notes due 2025	86,052		255,021

Notes due 2024	—		88,140
Less: unamortized discount and issuance costs	—		(19,119)
Carrying amount of Notes due 2024	—		69,021

Notes due 2023	5,000		5,000
Less: unamortized issuance costs	(62)		(102)
Carrying amount of Notes due 2023	4,938		4,898

Sale of long-term financing receivable recorded as debt	—		1,925


Total carrying amount of debt	1,037,646		330,865

Less: current portion of convertible notes and long-term financing receivable recorded as debt	(86,052)		(325,967)
Debt, non-current	$	951,594	$	4,898

The following table presents the total amount of interest cost recognized in the statement of operations relating to the Notes due 2028:


	Year Ended December 31, 2021
		(In thousands)

Amortization of debt discount		$	16,401
Amortization of debt issuance costs		785
Total interest cost recognized		$	17,186

The following table presents the total amount of interest cost recognized in the statement of operations relating to the Notes due 2026:


	Year Ended December 31, 2021
		(In thousands)

Amortization of debt discount		$	18,735
Amortization of debt issuance costs		1,347
Total interest cost recognized		$	20,082

The following table presents the total amount of interest cost recognized relating to the Notes due 2025:



	Years Ended December 31,
		2021		2020
		(In thousands)
Contractual interest expense		$	342	$	649
Amortization of debt discount		5,529		10,072
Amortization of debt issuance costs		661		1,229
Total interest cost recognized		$	6,532	$	11,950

The following table presents the total amount of interest cost recognized in the statement of operations relating to the Notes due 2024:


	Years Ended December 31,
		2021		2020
		(In thousands)
Contractual interest expense		$	8	$	1,284
Amortization of debt discount		772		6,325
Amortization of debt issuance costs		74		646
Total interest cost recognized		$	854	$	8,255

The following table presents the amount of interest cost recognized relating to the contractual interest coupon and the amortization of debt issuance costs of the Notes due 2023.



	Years Ended December 31,
		2021		2020
		(In thousands)
Contractual interest expense		$	200	$	200

Amortization of debt issuance costs		40		40
Total interest costs recognized		$	240	$	240

COMMITMENTS AND CONTINGENCIES (Tables)

12 Months Ended

Dec. 31, 2021

Commitments and Contingencies Disclosure [Abstract]

Components of Lease

The components of lease expense are presented as follows:


	Years Ended December 31,
		2021		2020
		(In thousands)
Operating lease costs		$	7,049	$	5,332

The components of lease liabilities are presented as follows:


	December 31, 2021		December 31, 2020
	(In thousands)
Operating lease liabilities, current (Accrued liabilities)	$	3,830	$	4,542
Operating lease liabilities, non-current (Other liabilities)	11,920		15,209
Total operating lease liabilities	$	15,750	$	19,751

Supplemental lease information:
Weighted average remaining lease term	5.9 years		6.4 years
Weighted average discount rate	7.4%		7.7%

Supplemental cash flow and other information related to operating leases, are as follows:


	Years Ended December 31,
		2021		2020
		(In thousands)
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases		$	5,855	$	4,762

Non-cash investing activities:
Lease liabilities arising from obtaining right-of-use assets		$	708	$	10,625

Schedule of Future Minimum Rental Payments for Operating Leases

Undiscounted cash flows of operating lease liabilities as of December 31, 2021 are as follows:


	Lease Amounts
	(In thousands)
Year:
2022	$	4,771
2023	4,160
2024	3,198
2025	2,422
2026	1,395
Thereafter	2,680
Total lease payments	18,626
Less: imputed lease interest	(2,876)
Total lease liabilities	$	15,750

STOCK-BASED COMPENSATION (Tables)

12 Months Ended

Dec. 31, 2021

Share-based Payment Arrangement [Abstract]

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions


	Years Ended December 31,
		2021	2020		2019
Weighted average grant date fair value		**	$	38.45	$	9.16
Expected term (in years)		**	3.8		3.8
Expected volatility		**	86.4%		89.1%
Annual risk-free rate of return		**	0.1%		2.1%
Dividend yield		**	—%		—%

** No stock options were granted during the year ended December 31, 2021.

Summary of the Components of Total Stock-Based Compensation Expense

The following table summarizes the components of total stock-based compensation expense included in the consolidated statements of operations for the periods presented.


	Years Ended December 31,
		2021		2020		2019
		(In thousands)
Cost of revenues		$	7,366	$	3,759	$	1,650
Research and development		33,927		12,701		4,897
Sales and marketing		37,434		11,548		5,678
General and administrative		35,559		14,495		7,216
Restructuring		—		—		735
Total		$	114,286	$	42,503	$	20,176
Income tax benefit included in the provision for incomes taxes		$	97,129	$	61,389	$	8,185

Summary of Stock-Based Compensation Associated with Each Type of Award

The following table summarizes the various types of stock-based compensation expense for the periods presented.


	Years Ended December 31,
		2021		2020		2019
		(In thousands)
Stock options, RSUs and PSUs		$	110,142	$	39,841	$	19,216
Employee stock purchase plan		4,144		2,662		960

Total		$	114,286	$	42,503	$	20,176

Summary of Stock Option Activity

The following is a summary of stock option activity.


	Number of Shares Outstanding	Weighted- Average Exercise Price per Share		Weighted- Average Remaining Contractual Term	Aggregate Intrinsic Value (1)
	(In thousands)			(Years)	(In thousands)
Outstanding at December 31, 2018	6,772	$	1.76
Granted	43	14.58
Exercised	(2,616)	1.22			$	31,093
Canceled	(102)	4.07
Outstanding at December 31, 2019	4,097	$	2.18
Granted	11	64.17
Exercised	(1,494)	2.74			$	114,089
Canceled	(82)	6.94
Outstanding at December 31, 2020	2,532	$	1.96
Granted	—	—
Exercised	(267)	2.44			$	42,091
Canceled	(1)	0.83
Outstanding at December 31, 2021	2,264	$	1.90	2.8	$	409,834
Vested and expected to vest at December 31, 2021	2,264	$	1.90	2.8	$	409,834
Exercisable at December 31, 2021	2,262	$	1.90	2.8	$	409,550

Summary of Stock Option Outstanding

The following table summarizes information about stock options outstanding at December 31, 2021.


	Options Outstanding				Options Exercisable
Range of Exercise Prices	Number of Shares	Weighted- Average Remaining Life	Weighted- Average Exercise Price		Number of Shares	Weighted- Average Exercise Price
	(In thousands)	(Years)			(In thousands)
$0.70 —– $1.11	486	3.3	$	0.86	486	$	0.85
$1.29 —– $1.29	1,000	2.7	1.29		1,000	1.28
$1.31 —– $1.31	556	2.3	1.31		556	1.31
$1.53 —– $14.58	211	3.1	5.65		209	5.65
$64.17 —– $64.17	11	5.4	64.17		11	64.17
Total	2,264	2.8	$	1.90	2,262	$	1.90

Summary of Restricted Stock Unit Activity

The following is a summary of RSU activity.


	Number of Shares Outstanding	Weighted- Average Fair Value per Share at Grant Date		Weighted- Average Remaining Contractual Term	Aggregate Intrinsic Value (1)
	(In thousands)			(Years)	(In thousands)
Outstanding at December 31, 2018	4,352	$	3.52
Granted	2,112	11.50
Vested	(1,707)	3.87			$	27,156
Canceled	(494)	4.81
Outstanding at December 31, 2019	4,263	$	7.19
Granted	1,550	55.66
Vested	(2,085)	7.26			$	125,578
Canceled	(140)	19.47
Outstanding at December 31, 2020	3,588	$	27.61
Granted	1,301	179.88
Vested	(1,979)	20.47			$	364,665
Canceled	(124)	88.50
Outstanding at December 31, 2021	2,786	$	100.73	1.2	$	509,864
Expected to vest at December 31, 2021	2,786	$	100.73	1.2	$	509,864

Share-based Compensation, Performance Shares Award Outstanding Activity

The following is a summary of PSU activity.


	Number of Shares Outstanding	Weighted- Average Fair Value per Share at Grant Date		Weighted- Average Remaining Contractual Term	Aggregate Intrinsic Value (1)
	(In thousands)			(Years)	(In thousands)
Outstanding at December 31, 2018	1,330	$	4.66
Granted	1,052	9.48
Vested	(1,063)	4.62			$	10,818
Canceled	(364)	5.16
Outstanding at December 31, 2019	955	$	9.83
Granted	989	31.12
Vested	(1,450)	10.20			$	52,144
Canceled	—	—
Outstanding at December 31, 2020	494	$	51.10
Granted	715	131.60
Vested	(494)	59.19			$	91,803
Canceled	(270)	52.75
Outstanding at December 31, 2021	445	$	169.82	0.2	$	81,456

Schedule of Share-based Compensation, Employee Stock Purchase Plan, Activity

A summary of ESPP activity for the years presented is as follows: (in thousands, except per share data):


	Years Ended December 31,
	2021		2020		2019
Proceeds from common stock issued under ESPP	$	6,832	$	4,304	$	1,692
Shares of common stock issued	235		347		315
Weighted-average price per share	$	29.12	$	12.41	$	5.37

INCOME TAXES (Tables)

12 Months Ended

Dec. 31, 2021

Income Tax Disclosure [Abstract]

Schedule of Domestic and Foreign Components of Loss before Provision for Income Taxes

The domestic and foreign components of income before income taxes consisted of the following:


	Years Ended December 31,
	2021		2020		2019
	(In thousands)
United States	$	102,886	$	112,727	$	85,520
Foreign	18,042		6,683		4,594
Income before income taxes	$	120,928	$	119,410	$	90,114

Schedule of Provision for Income Taxes

The income taxes (benefit) for the years presented is as follows:


	Years Ended December 31,
	2021		2020		2019
	(In thousands)
Current:
Federal	$	—	$	—	$	—
State	488		636		327
Foreign	6,232		1,896		1,589
	6,720		2,532		1,916
Deferred:
Federal	(28,398)		(13,445)		(56,959)
State	(4,380)		(3,672)		(17,458)
Foreign	1,537		—		1,467
	(31,241)		(17,117)		(72,950)
Income taxes (benefit)	$	(24,521)	$	(14,585)	$	(71,034)

Schedule of Effective Income Tax Rate Reconciliation


	Years Ended December 31,
	2021		2020		2019
	(In thousands)
Income tax (benefit) provision at statutory federal rate	$	27,681	$	25,076	$	18,929
State taxes, net of federal benefit	489		(3,098)		(17,197)
Change in valuation allowance	—		—		(71,300)
Foreign tax rate and tax law differential	1,073		611		1,206
Tax credits	(15,632)		(5,835)		(1,803)
Stock-based compensation	(80,950)		(50,818)		(8,072)
Other permanent items	178		(253)		31

Other nondeductible/nontaxable items	2,316		1,525		2,765
Uncertain tax positions	6,911		1,530		504

GILTI	—		—		1,086
Section 162(m)	25,812		11,469		2,817
Convertible note settlements	8,223		—		—
Warrant mark-to-mark adjustment	(622)		5,208		—
Income tax (benefit)	$	(24,521)	$	(14,585)	$	(71,034)

Schedule of Deferred Tax Assets and Liabilities

A summary of significant components of the Company’s deferred tax assets and liabilities as of December 31, 2021 and 2020 is as follows:


	December 31,
	2021		2020
	(In thousands)
Deferred tax assets:
Allowances and reserves	$	18,764	$	13,146
Net operating loss and tax credit carryforwards	65,699		53,116
Stock-based compensation	12,935		4,598
Deferred revenue	27,778		20,765
Fixed assets and intangibles	39,711		8,706
Sec. 163(j) interest carryforward	10,749		4,401
Other	1,609		7,007
Subtotal	177,245		111,739

Total deferred tax assets	177,245		111,739
Deferred tax liabilities:
Goodwill	(31,805)		(1,719)
Unremitted foreign earnings	(2,226)		(7)
Deferred cost of goods sold	(23,713)		(17,545)
Total deferred tax liabilities	(57,744)		(19,271)
Net deferred tax asset	$	119,501	$	92,468

Schedule of Reconciliation of Total Amounts of Unrecognized Tax Benefits

A tabular reconciliation of the total amounts of unrecognized tax benefits for the years presented is as follows (in thousands):


	Years Ended December 31,
	2021		2020		2019
Unrecognized tax benefits—at beginning of year	$	8,421	$	6,589	$	6,325
Increases in balances related to tax positions taken in prior years	4,391		—		—
Decreases in balances related to tax positions taken in prior years	—		—		(370)
Increases in balances related to tax positions taken in current year	8,301		2,006		771

Lapses in statutes of limitations	(209)		(174)		(137)
Unrecognized tax benefits—at end of year	$	20,904	$	8,421	$	6,589

NET INCOME PER SHARE (Tables)

12 Months Ended

Dec. 31, 2021

Earnings Per Share [Abstract]

Schedule of Computation of Basic and Diluted Net Income (Loss) Per Share

The following table presents the computation of basic and diluted net income per share for the periods presented.


	Years Ended December 31,
		2021		2020		2019
		(In thousands, except per share data)
Numerator:
Net income		$	145,449	$	133,995	$	161,148
Notes due 2023 interest and financing costs, net		177		177		1,088
Adjusted net income		$	145,626	$	134,172	$	162,236

Denominator:
Shares used in basic per share amounts:
Weighted average common shares outstanding		134,025		125,561		116,713

Shares used in diluted per share amounts:
Weighted average common shares outstanding		134,025		125,561		116,713
Effect of dilutive securities:
Employee stock-based awards		4,918		6,997		8,964
Notes due 2023		900		900		5,516
Notes due 2024		768		4,449		451
2024 Warrants		647		4,011		—
Notes due 2025		929		—		—
2025 Warrants		691		—		—




Weighted average common shares outstanding for diluted calculation		142,878		141,918		131,644

Basic and diluted net income per share
Net income per share, basic		$	1.09	$	1.07	$	1.38
Net income per share, diluted		$	1.02	$	0.95	$	1.23

Schedule of Potentially Dilutive Securities Excluded from the Computation of Diluted Net Income (Loss) Per Share


	Years Ended December 31,
		2021	2020	2019
		(In thousands)



Employee stock-based awards		32	43	185
Notes due 2028		1,082	—	—
2028 Warrants		2,184	—	—
Notes due 2026		1,328	—	—
2026 Warrants		2,225	—	—
Notes due 2025		—	197
2025 Warrants		—	1,254	—


2024 Warrants		—	—	300


Total		6,851	1,494	485

SEGMENT AND GEOGRAPHIC INFORMATION (Tables)

12 Months Ended

Dec. 31, 2021

Segment Reporting [Abstract]

Summary of Long-Lived Assets by Geographic Region

The following table presents long-lived assets by geographic region as of and for the periods presented:

Long-Lived Assets


	December 31,
	2021		2020
	(In thousands)
United States	$	37,685	$	19,870
India	17,490		4,371
China	12,906		9,948
Mexico	8,735		4,808
New Zealand	4,622		3,837
Other	729		151
Total	$	82,167	$	42,985

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Jan. 01, 2022	Mar. 31, 2020	Mar. 09, 2020
Fair Value, Option, Quantitative Disclosures [Line Items]
Accrued interest receivable	$ 2,100,000
Asset impairment	0	$ 0	$ 1,100,000
Goodwill, impairment loss	0	0	0
Impairment of intangible assets	$ 0	0	0
Product warranty, term	25 years
Advertising costs	$ 16,200,000	800,000	$ 600,000
Additional paid in capital	(837,924,000)	(534,744,000)
Accumulated deficit	$ 405,737,000	$ 51,186,000
Cumulative Effect, Period of Adoption, Adjustment \| Forecast \| Accounting Standards Update 2020-06
Fair Value, Option, Quantitative Disclosures [Line Items]
Additional paid in capital				$ 207,900,000
Convertible debt				244,500,000
Deferred income tax liabilities				62,300,000
Accumulated deficit				$ 25,700,000
Monitoring Hardware And Service
Fair Value, Option, Quantitative Disclosures [Line Items]
Capitalized contract cost, amortization period	6 years
First and Second Generation
Fair Value, Option, Quantitative Disclosures [Line Items]
Product warranty, term	15 years
Third and Fourth Generation
Fair Value, Option, Quantitative Disclosures [Line Items]
Product warranty, term	25 years
Envoy Communications Gateway
Fair Value, Option, Quantitative Disclosures [Line Items]
Product warranty, term	5 years
AC Battery Storage Solution
Fair Value, Option, Quantitative Disclosures [Line Items]
Product warranty, term	10 years
Convertible Senior Notes Due 2025 \| Convertible Notes
Fair Value, Option, Quantitative Disclosures [Line Items]
Debt instrument face amount					$ 320,000,000	$ 320,000,000
Interest rate					0.25%	0.25%
Minimum
Fair Value, Option, Quantitative Disclosures [Line Items]
Property, plant and equipment, useful life	3 years
Intangible assets, estimated useful life	5 years
Period failure rate measurement lags product sale	3 months
Minimum \| Communication Accessories
Fair Value, Option, Quantitative Disclosures [Line Items]
Service period	5 years
Maximum
Fair Value, Option, Quantitative Disclosures [Line Items]
Property, plant and equipment, useful life	10 years
Intangible assets, estimated useful life	9 years
Period failure rate measurement lags product sale	9 months
Maximum \| Communication Accessories
Fair Value, Option, Quantitative Disclosures [Line Items]
Service period	12 years

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Activity in Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance, at beginning of year	$ 462	$ 564	$ 2,138
Net charges to expense or reduction in revenue	1,140	425	217
Write-offs, net of recoveries	(12)	(527)	(1,791)
Balance, at end of year	$ 1,590	$ 462	$ 564

REVENUE RECOGNITION - Summary of Disaggregated Revenue by Primary Geographical Market and Timing of Revenue Recognition (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenues	$ 1,382,049	$ 774,425	$ 624,333
Products delivered at a point in time
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenues	1,323,960	728,254
Products and services delivered over time
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenues	58,089	46,171
U.S.
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenues	1,108,801	637,879
International
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenues	$ 273,248	$ 136,546

- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8906-108599

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 40
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e9031-108599

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 41
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e9038-108599

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8933-108599

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8933-108599

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130543-203045

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8736-108599

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8736-108599

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 42
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e9054-108599

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130545-203045

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 924
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 11.L)
-URI http://asc.fasb.org/extlink&oid=6472922&loc=d3e499488-122856

+ Details

REVENUE RECOGNITION - Summary of Contract Assets and Contract Liabilities from Contracts with Customers (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Receivables	$ 333,626	$ 182,165
Short-term contract assets (Prepaid expenses and other assets)	23,508	17,879
Long-term contract assets (Other assets)	69,583	51,986
Short-term contract liabilities (Deferred revenues, current)	62,670	47,665
Long-term contract liabilities (Deferred revenues, non-current)	$ 187,186	$ 125,473

REVENUE RECOGNITION - Narrative (Details)	12 Months Ended
REVENUE RECOGNITION - Narrative (Details)	Dec. 31, 2021 USD ($)
Revenue from Contract with Customer [Abstract]
Contract asset impairment charges	$ 0

REVENUE RECOGNITION - Summary of Significant Changes in the Balances of Contract Liabilities and Assets (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($)
Contract Assets
Balance, beginning of period	$ 69,865
Amount recognized	(21,894)
Increase	45,120
Balance, end of period	93,091
Contract Liabilities
Balance, beginning of period	173,138
Revenue recognized	(64,793)
Increase due to billings	141,511
Balance, end of period	$ 249,856

REVENUE RECOGNITION - Summary of Estimated Revenue Expected to be Recognized in Future Periods (Details) $ in Thousands	Dec. 31, 2021 USD ($)
Revenue from Contract with Customer [Abstract]
Total estimated revenue expected to be recognized in future periods	$ 249,856
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue from Contract with Customer [Abstract]
Total estimated revenue expected to be recognized in future periods	$ 62,671
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total estimated revenue expected to be recognized in future periods, expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue from Contract with Customer [Abstract]
Total estimated revenue expected to be recognized in future periods	$ 55,497
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total estimated revenue expected to be recognized in future periods, expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue from Contract with Customer [Abstract]
Total estimated revenue expected to be recognized in future periods	$ 50,300
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total estimated revenue expected to be recognized in future periods, expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue from Contract with Customer [Abstract]
Total estimated revenue expected to be recognized in future periods	$ 43,362
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total estimated revenue expected to be recognized in future periods, expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01
Revenue from Contract with Customer [Abstract]
Total estimated revenue expected to be recognized in future periods	$ 27,607
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total estimated revenue expected to be recognized in future periods, expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01
Revenue from Contract with Customer [Abstract]
Total estimated revenue expected to be recognized in future periods	$ 10,419
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total estimated revenue expected to be recognized in future periods, expected timing

INVENTORY - Summary of Inventory (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Inventory Disclosure [Abstract]
Raw materials	$ 25,429	$ 10,140
Finished goods	48,971	31,624
Total inventory	$ 74,400	$ 41,764

PROPERTY AND EQUIPMENT, NET - Summary of Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 159,533	$ 104,687
Less accumulated depreciation and amortization	(77,366)	(61,702)
Property and equipment, net	$ 82,167	42,985
Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	10 years
Equipment and machinery
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 95,365	63,411
Equipment and machinery \| Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Equipment and machinery \| Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	10 years
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 3,197	2,532
Furniture and fixtures \| Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	5 years
Furniture and fixtures \| Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	10 years
Computer equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 5,861	2,972
Computer equipment \| Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Computer equipment \| Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	5 years
Capitalized software costs
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 28,118	17,004
Capitalized software costs \| Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Capitalized software costs \| Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	5 years
Building and leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 12,546	9,021
Building and leasehold improvements \| Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Building and leasehold improvements \| Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life	10 years
Land
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 114	0
Construction in process
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 14,332	$ 9,747

PROPERTY AND EQUIPMENT, NET - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 16.7	$ 9.7	$ 7.3
Unamortized capitalized software costs	$ 12.6	$ 4.8

BUSINESS COMBINATION - Narrative (Details) - USD ($)					12 Months Ended
BUSINESS COMBINATION - Narrative (Details) - USD ($)	Dec. 31, 2021	Dec. 13, 2021	Mar. 31, 2021	Jan. 25, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Contingent consideration in connection with the acquisition					$ 3,500,000	$ 0	$ 0
ClipperCreek
Business Acquisition [Line Items]
Voting interests acquired	100.00%			100.00%	100.00%
Purchase price	$ 113,100,000
Contingency payable, maximum	40,000,000				$ 40,000,000
Acquisition costs					500,000
365 Pronto
Business Acquisition [Line Items]
Voting interests acquired		100.00%
Purchase price		$ 69,900,000
Contingency payable, maximum		$ 11,000,000
Goodwill, expected tax deductible amount	$ 0				0
Acquisition costs					500,000
DIN's
Business Acquisition [Line Items]
Purchase price			$ 24,800,000
Goodwill, expected tax deductible amount			0
Acquisition costs					1,900,000
DIN's \| Additional Consideration, Equal Monthly Installments
Business Acquisition [Line Items]
Contingency payable, maximum			$ 5,000,000
Timing of monthly installment payments			1 year
DIN's \| Additional Consideration, Payable One Year Anniversary
Business Acquisition [Line Items]
Contingency payable, maximum			$ 5,000,000
Sofdesk
Business Acquisition [Line Items]
Purchase price				$ 31,988,000
Contingency payable, maximum				3,700,000
Goodwill, expected tax deductible amount				0
Contingent consideration in connection with the acquisition				3,500,000
Consideration transferred for business acquisition				$ 35,488,000
Acquisition costs					$ 2,000,000

BUSINESS COMBINATION - Summary of Fair Values of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 13, 2021	Mar. 31, 2021	Jan. 25, 2021	Dec. 31, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Goodwill	$ 181,254				$ 24,783	$ 24,783
ClipperCreek
Business Acquisition [Line Items]
Net tangible assets acquired	8,387
Intangible assets	37,800
Goodwill	66,916
Net assets acquired	$ 113,103
365 Pronto
Business Acquisition [Line Items]
Net tangible assets acquired		$ 38
Intangible assets		19,500
Deferred tax liabilities		(2,906)
Goodwill		53,280
Net assets acquired		69,912
365 Pronto \| Customer relationship
Business Acquisition [Line Items]
Intangible assets		$ 1,100
DIN's
Business Acquisition [Line Items]
Net tangible assets acquired			$ 1,281
Intangible assets			11,700
Goodwill			11,804
Net assets acquired			24,785
DIN's \| Customer relationship
Business Acquisition [Line Items]
Intangible assets			$ 11,700
Sofdesk
Business Acquisition [Line Items]
Net tangible assets acquired				$ 1,441
Intangible assets				9,200
Deferred tax asset				457
Goodwill				24,390
Net assets acquired				35,488
Sofdesk \| Customer relationship
Business Acquisition [Line Items]
Intangible assets				$ 1,800

BUSINESS COMBINATION - Summary of Identifiable Intangible Assets Acquired (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 13, 2021	Mar. 31, 2021	Jan. 25, 2021
ClipperCreek
Business Acquisition [Line Items]
Intangible assets	$ 37,800
ClipperCreek \| Order backlog
Business Acquisition [Line Items]
Intangible assets	600
ClipperCreek \| Trade name
Business Acquisition [Line Items]
Intangible assets	$ 37,200
Useful Life	5 years
365 Pronto
Business Acquisition [Line Items]
Intangible assets		$ 19,500
365 Pronto \| Developed technology
Business Acquisition [Line Items]
Intangible assets		$ 18,400
Useful Life		5 years
365 Pronto \| Customer relationship
Business Acquisition [Line Items]
Intangible assets		$ 1,100
Useful Life		5 years
DIN's
Business Acquisition [Line Items]
Intangible assets			$ 11,700
DIN's \| Customer relationship
Business Acquisition [Line Items]
Intangible assets			$ 11,700
Useful Life			5 years
Sofdesk
Business Acquisition [Line Items]
Intangible assets				$ 9,200
Sofdesk \| Developed technology
Business Acquisition [Line Items]
Intangible assets				$ 6,900
Useful Life				5 years
Sofdesk \| Customer relationship
Business Acquisition [Line Items]
Intangible assets				$ 1,800
Useful Life				5 years
Sofdesk \| Trade name
Business Acquisition [Line Items]
Intangible assets				$ 500
Useful Life				5 years

BUSINESS COMBINATION - Summary of Pro Forma Results (Details) - ClipperCreek - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Business Acquisition [Line Items]
Net revenues	$ 1,401,803	$ 790,791
Net income	$ 145,798	$ 139,126

BUSINESS COMBINATION - Summary of Consideration Transferred for Business Acquisition (Details) - USD ($) $ in Thousands		12 Months Ended
	Jan. 25, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Fair value of contingent consideration		$ 3,500	$ 0	$ 0
Sofdesk
Business Acquisition [Line Items]
Cash consideration	$ 31,988
Fair value of contingent consideration	3,500
Total	$ 35,488

GOODWILL AND INTANGIBLE ASSETS - Schedule of Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Goodwill [Roll Forward]
Beginning balance	$ 24,783	$ 24,783
Goodwill acquired	156,390	0
Currency translation adjustment	81	0
Ending balance	$ 181,254	$ 24,783

GOODWILL AND INTANGIBLE ASSETS - Schedule of Acquired Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Other indefinite-lived intangibles	$ 286	$ 286
Intangible assets with finite lives:
Additions	78,450	3,321
Accumulated Amortization	(20,499)	(10,999)
Net	97,472
Total purchased intangible assets, Gross	39,807	36,486
Total purchased intangible assets, Net	97,758	28,808
Developed technology
Intangible assets with finite lives:
Gross	13,100	13,100
Additions	25,550	0
Accumulated Amortization	(8,958)	(5,276)
Net	29,692	7,824
Customer relationship
Intangible assets with finite lives:
Gross	26,421	23,100
Additions	14,600	3,321
Accumulated Amortization	(11,448)	(5,723)
Net	29,573	20,698
Trade names
Intangible assets with finite lives:
Gross	0	0
Additions	37,700	0
Accumulated Amortization	(93)	0
Net	37,607	0
Order backlog
Intangible assets with finite lives:
Gross	0	0
Additions	600	0
Accumulated Amortization	0	0
Net	$ 600	$ 0

GOODWILL AND INTANGIBLE ASSETS - Amortization Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 9,500	$ 5,092
Developed technology
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	3,681	2,183
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	5,726	2,909
Trade names
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 93	$ 0

GOODWILL AND INTANGIBLE ASSETS - Expected Future Amortization Expense (Details) $ in Thousands	Dec. 31, 2021 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
2022	$ 22,212
2023	21,856
2024	19,059
2025	17,744
2026	14,185
Thereafter	2,416
Net	$ 97,472

CASH EQUIVALENTS AND MARKETABLE SECURITIES - Schedule of Investments (Details) $ in Thousands	Dec. 31, 2021 USD ($)
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 969,740
Gross Unrealized Gains	0
Gross Unrealized Losses	(2,859)
Fair Value	966,881
Cash and Cash Equivalents
Debt Securities, Available-for-sale [Line Items]
Fair Value	69,546
Marketable Securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	897,335
Money market funds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	35,789
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Fair Value	35,789
Money market funds \| Cash and Cash Equivalents
Debt Securities, Available-for-sale [Line Items]
Fair Value	35,789
Money market funds \| Marketable Securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	0
Certificate of deposit
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	16,001
Gross Unrealized Gains	0
Gross Unrealized Losses	(2)
Fair Value	15,999
Certificate of deposit \| Cash and Cash Equivalents
Debt Securities, Available-for-sale [Line Items]
Fair Value	6,000
Certificate of deposit \| Marketable Securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	9,999
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	215,964
Gross Unrealized Gains	0
Gross Unrealized Losses	(114)
Fair Value	215,850
Commercial paper \| Cash and Cash Equivalents
Debt Securities, Available-for-sale [Line Items]
Fair Value	26,997
Commercial paper \| Marketable Securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	188,853
Corporate notes and bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	199,244
Gross Unrealized Gains	0
Gross Unrealized Losses	(872)
Fair Value	198,372
Corporate notes and bonds \| Cash and Cash Equivalents
Debt Securities, Available-for-sale [Line Items]
Fair Value	760
Corporate notes and bonds \| Marketable Securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	197,612
U.S. Treasuries
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	14,999
Gross Unrealized Gains	0
Gross Unrealized Losses	(1)
Fair Value	14,998
U.S. Treasuries \| Cash and Cash Equivalents
Debt Securities, Available-for-sale [Line Items]
Fair Value	0
U.S. Treasuries \| Marketable Securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	14,998
U.S. Government agencies
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	487,743
Gross Unrealized Gains	0
Gross Unrealized Losses	(1,870)
Fair Value	485,873
U.S. Government agencies \| Cash and Cash Equivalents
Debt Securities, Available-for-sale [Line Items]
Fair Value	0
U.S. Government agencies \| Marketable Securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	$ 485,873

CASH EQUIVALENTS AND MARKETABLE SECURITIES - Schedule of Contractual Maturity (Details) $ in Thousands	Dec. 31, 2021 USD ($)
Cash and Cash Equivalents [Abstract]
Contractual maturities, Due within one year, Amortized Cost	$ 533,237
Contractual maturities, Due within one year, Fair Value	532,689
Contractual maturities, Due within one to three years, Amortized Cost	436,503
Contractual maturities, Due within one to three years, Fair Value	434,192
Amortized Cost	969,740
Fair Value	$ 966,881

ACCRUED LIABILITIES - Schedule of Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Accrued Liabilities [Abstract]
Salaries, commissions, incentive compensation and benefits	$ 13,062	$ 6,634
Customer rebates and sales incentives	79,038	36,622
Freight	20,522	10,300
Operating lease liabilities, current	3,830	4,542
Liability due to supply agreements	14,653	5,500
Contingent consideration	3,710	0
Post combination expense accrual	8,602	0
Other	14,495	12,944
Total accrued liabilities	$ 157,912	$ 76,542

WARRANTY OBLIGATIONS - Summary of Warranty Activities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Changes in the Company's product warranty liability
Warranty obligations, beginning of period	$ 45,913	$ 37,098	$ 31,294
Accruals for warranties issued during period	18,098	7,021	5,244
Changes in estimates	19,414	9,954	8,591
Settlements	(15,073)	(12,811)	(10,881)
Increase due to accretion expense	4,654	3,255	2,326
Other	371	1,396	524
Warranty obligations, end of period	73,377	45,913	37,098
Less: current portion	(19,395)	(11,260)	(10,078)
Non-current	$ 53,982	$ 34,653	$ 27,020

WARRANTY OBLIGATIONS - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Product Warranty Liability [Line Items]
Additional warranty expense	$ 19,414	$ 9,954	$ 8,591
Field Performance Data And Diagnostic Root-Cause Failure Analysis
Product Warranty Liability [Line Items]
Additional warranty expense	11,600
Increase In Replacement Cost Assumption Changes
Product Warranty Liability [Line Items]
Additional warranty expense	$ 7,800
Failure Rates
Product Warranty Liability [Line Items]
Additional warranty expense		8,800
Failure Rates \| Second And Third Generations
Product Warranty Liability [Line Items]
Additional warranty expense			3,100
Increased Tariffs And Labor Reimbursement Costs
Product Warranty Liability [Line Items]
Additional warranty expense		$ 1,200
Increased U.S. Tariffs For Products Manufactured In China
Product Warranty Liability [Line Items]
Additional warranty expense			$ 5,500

FAIR VALUE MEASUREMENTS - Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Assets [Abstract]
Marketable securities:	$ 966,881
Liabilities:
Contingent consideration	3,710	$ 0
Certificate of deposit
Assets [Abstract]
Marketable securities:	15,999
Commercial paper
Assets [Abstract]
Marketable securities:	215,850
Corporate notes and bonds
Assets [Abstract]
Marketable securities:	198,372
U.S. Government agencies
Assets [Abstract]
Marketable securities:	485,873
U.S. Treasuries
Assets [Abstract]
Marketable securities:	14,998
Recurring \| Level 1
Assets [Abstract]
Investments in debt securities	0	0
Total assets measured at fair value	35,789	654,699
Liabilities:
Contingent consideration	0	0
Warranty obligations
Current	0	0
Non-current	0	0
Total warranty obligations measured at fair value	0	0
Total liabilities measured at fair value	0	0
Recurring \| Level 1 \| Certificate of deposit
Assets [Abstract]
Marketable securities:	0	0
Recurring \| Level 1 \| Commercial paper
Assets [Abstract]
Marketable securities:	0	0
Recurring \| Level 1 \| Corporate notes and bonds
Assets [Abstract]
Marketable securities:	0	0
Recurring \| Level 1 \| U.S. Government agencies
Assets [Abstract]
Marketable securities:	0	0
Recurring \| Level 1 \| U.S. Treasuries
Assets [Abstract]
Marketable securities:	0	0
Recurring \| Level 1 \| Money market funds
Assets [Abstract]
Cash and cash equivalents	35,789	654,699
Recurring \| Level 1 \| Certificate of deposit
Assets [Abstract]
Cash and cash equivalents	0	0
Recurring \| Level 1 \| Commercial paper
Assets [Abstract]
Cash and cash equivalents	0	0
Recurring \| Level 1 \| Corporate notes and bonds
Assets [Abstract]
Cash and cash equivalents	0	0
Recurring \| Level 2
Assets [Abstract]
Investments in debt securities	0	0
Total assets measured at fair value	931,092	0
Liabilities:
Contingent consideration	0	0
Warranty obligations
Current	0	0
Non-current	0	0
Total warranty obligations measured at fair value	0	0
Total liabilities measured at fair value	0	0
Recurring \| Level 2 \| Certificate of deposit
Assets [Abstract]
Marketable securities:	9,999	0
Recurring \| Level 2 \| Commercial paper
Assets [Abstract]
Marketable securities:	188,853	0
Recurring \| Level 2 \| Corporate notes and bonds
Assets [Abstract]
Marketable securities:	197,612	0
Recurring \| Level 2 \| U.S. Government agencies
Assets [Abstract]
Marketable securities:	485,873	0
Recurring \| Level 2 \| U.S. Treasuries
Assets [Abstract]
Marketable securities:	14,998	0
Recurring \| Level 2 \| Money market funds
Assets [Abstract]
Cash and cash equivalents	0	0
Recurring \| Level 2 \| Certificate of deposit
Assets [Abstract]
Cash and cash equivalents	6,000	0
Recurring \| Level 2 \| Commercial paper
Assets [Abstract]
Cash and cash equivalents	26,997	0
Recurring \| Level 2 \| Corporate notes and bonds
Assets [Abstract]
Cash and cash equivalents	760	0
Recurring \| Level 3
Assets [Abstract]
Investments in debt securities	41,042	0
Total assets measured at fair value	41,042	0
Liabilities:
Contingent consideration	3,710	0
Warranty obligations
Current	14,612	8,267
Non-current	36,395	20,469
Total warranty obligations measured at fair value	51,007	28,736
Total liabilities measured at fair value	54,717	28,736
Recurring \| Level 3 \| Certificate of deposit
Assets [Abstract]
Marketable securities:	0	0
Recurring \| Level 3 \| Commercial paper
Assets [Abstract]
Marketable securities:	0	0
Recurring \| Level 3 \| Corporate notes and bonds
Assets [Abstract]
Marketable securities:	0	0
Recurring \| Level 3 \| U.S. Government agencies
Assets [Abstract]
Marketable securities:	0	0
Recurring \| Level 3 \| U.S. Treasuries
Assets [Abstract]
Marketable securities:	0	0
Recurring \| Level 3 \| Money market funds
Assets [Abstract]
Cash and cash equivalents	0	0
Recurring \| Level 3 \| Certificate of deposit
Assets [Abstract]
Cash and cash equivalents	0	0
Recurring \| Level 3 \| Commercial paper
Assets [Abstract]
Cash and cash equivalents	0	0
Recurring \| Level 3 \| Corporate notes and bonds
Assets [Abstract]
Cash and cash equivalents	$ 0	$ 0

FAIR VALUE MEASUREMENTS - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	7 Months Ended	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2021	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Jan. 31, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment without readily determinable fair value							$ 5,000
Decrease in liability as a result of decreasing the profit element and risk premium input by 100 basis points			$ 900
Increase in liability as a result of decreasing the discount rate by 100 basis points			2,900
Decrease in liability as a result of increasing the discount rate by 100 basis points			2,300
Debt Securities, One
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in debt securities						$ 25,000
Debt Securities, Two
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in debt securities					$ 20,000
Proceeds from settlement	$ 26,600
Principal amount settled	20,000
Proceeds from interest and change in control premium		$ 6,600
Debt Securities, Three
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in debt securities				$ 13,000
Level 2 \| Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in debt securities	0	0	0				$ 0
Level 2 \| Recurring \| Convertible Notes \| Convertible Senior Notes Due 2028
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes payable fair value	594,400	594,400	594,400
Level 2 \| Recurring \| Convertible Notes \| Convertible Senior Notes Due 2026
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes payable fair value	642,300	642,300	642,300
Level 2 \| Recurring \| Convertible Notes \| Convertible Senior Notes Due 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes payable fair value	$ 240,000	$ 240,000	$ 240,000

FAIR VALUE MEASUREMENTS - Debt Securities Schedule of Fair Value (Details) - Investments in debt securities $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	$ 0
Investment	58,000
Fair value adjustments included in other (expense) income, net	9,611
Settlement	(26,569)
Balance at end of period	$ 41,042

FAIR VALUE MEASUREMENTS - Contingent Consideration Schedule of Fair Value (Details) - Contingent consideration $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	$ 0
Addition	3,500
Fair value adjustments included in other income (expense), net	210
Balance at end of period	$ 3,710

FAIR VALUE MEASUREMENTS - Schedule of Changes in Nonfinancial Liabilities Related to Warrant Obligations Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs (Details) - Recurring - Total warranty obligations measured at fair value - Level 3 - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	$ 28,736	$ 19,806
Accruals for warranties issued during period	18,098	7,021
Changes in estimates	10,844	5,039
Settlements	(11,248)	(7,781)
Increase due to accretion expense	4,654	3,255
Other	(77)	1,396
Balance at end of period	$ 51,007	$ 28,736

FAIR VALUE MEASUREMENTS - Summary of Significant Unobservable Inputs used in the Fair Value Measurement of Liabilities Designated as Level 3 (Details) - Recurring - Level 3 - Warranty obligations for microinverters sold since January 1, 2014	Dec. 31, 2021	Dec. 31, 2020
Profit element and risk premium
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warranty obligations, measurement input	15.00%	15.00%
Credit-adjusted risk-free rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warranty obligations, measurement input	12.00%	13.00%

RESTRUCTURING - Summary of Restructuring Charges (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 0	$ 0	$ 2,599,000
Asset impairments	0	0	1,100,000
Restructuring Plan 2018
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0	0	2,599,000
Redundancy and employee severance and benefit arrangements
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0	0	1,575,000
Redundancy and employee severance and benefit arrangements \| Restructuring Plan 2018
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0	0	1,575,000
Asset impairments
Restructuring Cost and Reserve [Line Items]
Asset impairments	0	0	1,124,000
Asset impairments \| Restructuring Plan 2018
Restructuring Cost and Reserve [Line Items]
Asset impairments	0	0	1,124,000
Lease loss reserves (benefit)
Restructuring Cost and Reserve [Line Items]
Restructuring reserve, accrual adjustment	0	0	(100,000)
Lease loss reserves (benefit) \| Restructuring Plan 2018
Restructuring Cost and Reserve [Line Items]
Restructuring reserve, accrual adjustment	$ 0	$ 0	$ (100,000)

DEBT - Long-term debt (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Total carrying amount of debt	$ 1,037,646	$ 330,865
Less: current portion of convertible notes and long-term financing receivable recorded as debt	(86,052)	(325,967)
Debt, non-current	951,594	4,898
Convertible Notes \| Convertible Senior Notes Due 2028
Debt Instrument [Line Items]
Long-term debt, gross	575,000	0
Less unamortized discount and issuance costs	(149,411)	0
Total carrying amount of debt	425,589	0
Convertible Notes \| Convertible Senior Notes Due 2026
Debt Instrument [Line Items]
Long-term debt, gross	632,500	0
Less unamortized discount and issuance costs	(111,433)	0
Total carrying amount of debt	521,067	0
Convertible Notes \| Convertible Senior Notes Due 2025
Debt Instrument [Line Items]
Long-term debt, gross	102,175	320,000
Less unamortized discount and issuance costs	(16,123)	(64,979)
Total carrying amount of debt	86,052	255,021
Less: current portion of convertible notes and long-term financing receivable recorded as debt	(102,200)
Convertible Notes \| Convertible Senior Notes Due 2024
Debt Instrument [Line Items]
Long-term debt, gross	0	88,140
Less unamortized discount and issuance costs	0	(19,119)
Total carrying amount of debt	0	69,021
Convertible Notes \| Convertible Senior Notes Due 2023
Debt Instrument [Line Items]
Long-term debt, gross	5,000	5,000
Less unamortized discount and issuance costs	(62)	(102)
Total carrying amount of debt	4,938	4,898
Financing Receivable \| Financing Receivable Recorded as Debt
Debt Instrument [Line Items]
Long-term debt, gross	$ 0	$ 1,925

DEBT - Convertible Senior Notes due in 2028 Narrative (Details) $ / shares in Units, shares in Millions		12 Months Ended
	Mar. 01, 2021 USD ($) trading_day $ / shares shares	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Debt Instrument [Line Items]
Deferred taxes		$ 122,470,000	$ 92,904,000
Payment for bonds hedge		286,235,000	89,056,000	$ 36,313,000
Proceeds from sale of warrants		220,800,000	$ 71,552,000	$ 29,818,000
Convertible Notes \| Convertible Senior Notes Due 2028
Debt Instrument [Line Items]
Debt instrument face amount	$ 575,000,000
Interest rate	0.00%
Proceeds from convertible debt	$ 566,400,000
Conversion ratio	0.0035104
Debt conversion price (in USD per share) \| $ / shares	$ 284.87
Convertible note, liability component	$ 415,000,000
Convertible note, equity component	160,000,000
Deferred taxes	40,100,000
Debt issuance costs	9,100,000
Unamortized debt issuance costs	6,600,000	5,800,000
Debt issuance costs, allocated to capital	$ 2,500,000
Unamortized discount		$ 143,600,000
Remaining discount amortization period		6 years 2 months 12 days
Conversion shares (in shares) \| shares	2.0
Payment for bonds hedge	$ 161,600,000
Warrants issued, strike price (in USD per share) \| $ / shares	$ 397.91
Proceeds from sale of warrants	$ 123,400,000
Convertible Notes \| Convertible Senior Notes Due 2028 \| Discount rate
Debt Instrument [Line Items]
Measurement input		0.0477
Period One \| Convertible Notes \| Convertible Senior Notes Due 2028
Debt Instrument [Line Items]
Threshold percentage	130.00%
Stock trigger price (in USD per share) \| $ / shares	$ 370.33
Number of threshold trading days \| trading_day	20
Number of consecutive trading days \| trading_day	30
Measurement period percentage of stock price trigger	98.00%
Period Two \| Convertible Notes \| Convertible Senior Notes Due 2028
Debt Instrument [Line Items]
Threshold percentage	100.00%
Number of consecutive trading days \| trading_day	5
Business day period after measurement period	5 days

DEBT - Schedule of Convertible Senior Notes due in 2028 (Details) - Convertible Notes - Convertible Senior Notes Due 2028 - USD ($) $ in Thousands	10 Months Ended	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2021
Debt Instrument [Line Items]
Amortization of debt discount	$ 16,401
Amortization of debt issuance costs	$ 785
Total interest cost recognized		$ 17,186

DEBT - Convertible Senior Notes due in 2026 Narrative (Details) $ / shares in Units, shares in Millions		12 Months Ended
	Mar. 01, 2021 USD ($) trading_day $ / shares shares	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Mar. 12, 2021 USD ($)
Debt Instrument [Line Items]
Deferred taxes		$ 122,470,000	$ 92,904,000
Payment for bonds hedge		286,235,000	89,056,000	$ 36,313,000
Proceeds from sale of warrants		220,800,000	$ 71,552,000	$ 29,818,000
Convertible Notes \| Convertible Senior Notes Due 2026
Debt Instrument [Line Items]
Debt instrument face amount	$ 575,000,000				$ 57,500,000
Interest rate	0.00%
Proceeds from convertible debt	$ 623,000,000
Conversion ratio	0.0032523
Debt conversion price (in USD per share) \| $ / shares	$ 307.47
Convertible note, liability component	$ 509,000,000
Convertible note, equity component	123,500,000
Deferred taxes	31,000,000
Debt issuance costs	10,000,000
Unamortized debt issuance costs	8,000,000	$ 6,700,000
Debt issuance costs, allocated to capital	$ 2,000,000
Effective percentage rate		4.44%
Unamortized discount		$ 104,800,000
Remaining discount amortization period		4 years 2 months 12 days
Conversion shares (in shares) \| shares	2.1
Payment for bonds hedge	$ 124,600,000
Warrants issued, strike price (in USD per share) \| $ / shares	$ 397.91
Proceeds from sale of warrants	$ 97,400,000
Convertible Notes \| Convertible Senior Notes Due 2026 \| Discount rate
Debt Instrument [Line Items]
Measurement input	0.0444
Period One \| Convertible Notes \| Convertible Senior Notes Due 2026
Debt Instrument [Line Items]
Threshold percentage	130.00%
Stock trigger price (in USD per share) \| $ / shares	$ 399.71
Number of threshold trading days \| trading_day	20
Number of consecutive trading days \| trading_day	30
Measurement period percentage of stock price trigger	98.00%
Period Two \| Convertible Notes \| Convertible Senior Notes Due 2026
Debt Instrument [Line Items]
Threshold percentage	100.00%
Number of consecutive trading days \| trading_day	5
Business day period after measurement period	5 days

DEBT - Schedule of Convertible Senior Notes due in 2026 (Details) - Convertible Notes - Convertible Senior Notes Due 2026 - USD ($) $ in Thousands	10 Months Ended	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2021
Debt Instrument [Line Items]
Amortization of debt discount	$ 18,735
Amortization of debt issuance costs	$ 1,347
Total interest cost recognized		$ 20,082

DEBT - Convertible Senior Notes due in 2025 Narrative (Details)			2 Months Ended	3 Months Ended		12 Months Ended
	Mar. 01, 2021 USD ($) shares	Mar. 09, 2020 USD ($) trading_day $ / shares shares	May 19, 2020 trading_day shares	Jun. 30, 2021 USD ($) shares	Mar. 31, 2021 USD ($) shares	Dec. 31, 2021 USD ($) $ / shares shares	Dec. 31, 2020 USD ($) $ / shares shares	Dec. 31, 2019 USD ($)	May 19, 2021 $ / shares shares	May 20, 2020 USD ($) $ / shares shares	Mar. 31, 2020 USD ($)
Debt Instrument [Line Items]
Principal amount outstanding						$ 1,037,646,000	$ 330,865,000
Common stock, par value (in usd per share) \| $ / shares						$ 0.00001	$ 0.00001		$ 0.00001	$ 0.00001
Common stock, shares authorized (in shares) \| shares			150,000,000			300,000,000	200,000,000		300,000,000	200,000,000
Deferred taxes						$ 122,470,000	$ 92,904,000
Partial repurchase of convertible notes						290,247,000	40,728,000	$ 0
Loss on partial settlement of convertible notes						56,497,000	3,037,000	0
Debt, current						86,052,000	325,967,000
Payment for bonds hedge						286,235,000	89,056,000	36,313,000
Proceeds from sale of warrants						220,800,000	71,552,000	$ 29,818,000
Warrants obligations measured at fair value										$ 96,400,000
Convertible Notes
Debt Instrument [Line Items]
Convertible notes embedded derivative										117,100,000
Convertible Notes \| Convertible Senior Notes Due 2025
Debt Instrument [Line Items]
Debt instrument face amount		$ 320,000,000									$ 320,000,000
Interest rate		0.25%									0.25%
Conversion ratio		0.0122637
Debt conversion price (in USD per share) \| $ / shares		$ 81.54
Proceeds from convertible debt		$ 313,000,000
Number of consecutive trading days \| trading_day			20
Principal amount outstanding						86,052,000	255,021,000
Convertible notes embedded derivative		68,700,000								116,300,000
Embedded derivative, host contract		$ 251,300,000
Deferred taxes										200,000
Debt issuance costs										$ 7,600,000
Partial repurchase of convertible notes					$ 217,700,000
Exercise of warrants related to convertible senior notes (in shares) \| shares	1,670,000			485
Equity component of convertible senior notes, net	$ 302,700,000			$ 100,000
Convertible note, liability component	184,500,000
Residual	4,300,000
Induced conversion of convertible debt expense	$ 37,500,000
Remaining expected life	4 years 1 month 6 days
Write off of debt discount	$ 38,500,000
Write off of deferred debt issuance cost	$ 4,100,000
Loss on partial settlement of convertible notes						9,400,000
Conversion of debt				$ 100,000
Debt, current						$ 102,200,000
Effective percentage rate						5.18%
Unamortized discount						$ 14,600,000	$ 58,600,000
Remaining discount amortization period						3 years 2 months 12 days
Conversion shares (in shares) \| shares		3,900,000
Payment for bonds hedge		$ 89,100,000
Warrants issued, strike price (in USD per share) \| $ / shares		$ 106.94
Proceeds from sale of warrants		$ 71,600,000
Convertible notes hedge settlements, shares received (in shares) \| shares					1,900,000
Warrants unwound, shares issued (in shares) \| shares					1,800,000
Convertible notes hedge transaction, options outstanding (in shares) \| shares						1,300,000
Warrants outstanding (in shares) \| shares						1,300,000
Convertible Notes \| Convertible Senior Notes Due 2025 \| Discount rate
Debt Instrument [Line Items]
Measurement input	0.0435
Period One \| Convertible Notes \| Convertible Senior Notes Due 2025
Debt Instrument [Line Items]
Number of threshold trading days \| trading_day		20
Number of consecutive trading days \| trading_day		30
Threshold percentage		130.00%
Stock trigger price (in USD per share) \| $ / shares						$ 106.00	$ 106.00
Period Two \| Convertible Notes \| Convertible Senior Notes Due 2025
Debt Instrument [Line Items]
Number of consecutive trading days \| trading_day		5
Threshold percentage		100.00%
Business day period after measurement period		5 days
Measurement period percentage of stock price trigger		98.00%

DEBT - Schedule of Convertible Senior Notes due in 2025 (Details) - Convertible Notes - Convertible Senior Notes Due 2025 - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Contractual interest expense	$ 342	$ 649
Amortization of debt discount	5,529	10,072
Amortization of debt issuance costs	661	1,229
Total interest cost recognized	$ 6,532	$ 11,950

DEBT - Convertible Senior Notes due 2024 Narrative (Details) $ / shares in Units, shares in Thousands		3 Months Ended	12 Months Ended
	Jun. 05, 2019 USD ($) $ / shares shares	Mar. 31, 2021 USD ($) shares	Dec. 31, 2021 USD ($) shares	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Debt Instrument [Line Items]
Partial repurchase of convertible notes			$ 290,247,000	$ 40,728,000	$ 0
Loss on partial settlement of convertible notes			56,497,000	3,037,000	0
Payment for bonds hedge			286,235,000	89,056,000	36,313,000
Proceeds from sale of warrants			$ 220,800,000	$ 71,552,000	$ 29,818,000
Convertible Notes \| Convertible Senior Notes Due 2024
Debt Instrument [Line Items]
Debt instrument face amount	$ 132,000,000
Interest rate	1.00%
Conversion ratio	0.0487781
Debt conversion price (in USD per share) \| $ / shares	$ 20.50
Proceeds from convertible debt	$ 128,000,000
Partial repurchase of convertible notes		$ 88,100,000
Repurchase amount		$ 25,500,000
Exercise of warrants related to convertible senior notes (in shares) \| shares			3,800
Equity component of convertible senior notes, net			$ 669,500,000
Convertible note, liability component			79,500,000
Residual			8,700,000
Write off of debt discount			16,800,000
Write off of deferred debt issuance cost			1,400,000
Loss on partial settlement of convertible notes			$ 9,600,000
Conversion shares (in shares) \| shares	6,400
Payment for bonds hedge	$ 36,300,000
Warrants sold (in shares) \| shares	6,400
Warrants issued, strike price (in USD per share) \| $ / shares	$ 25.23
Proceeds from sale of warrants	$ 29,800,000
Convertible notes hedge transaction, shares received (in shares) \| shares		1,100
Convertible notes hedge settlements, shares received (in shares) \| shares		2,700
Debt converted		$ 62,600,000
Warrants unwound, shares issued (in shares) \| shares		3,800

DEBT - Schedule of Convertible Senior Notes due 2024 (Details) - Convertible Notes - Convertible Senior Notes Due 2024 - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Contractual interest expense	$ 8	$ 1,284
Amortization of debt discount	772	6,325
Amortization of debt issuance costs	74	646
Total interest cost recognized	$ 854	$ 8,255

DEBT - Convertible Senior Notes due 2023 Narrative (Details) - Convertible Notes - Convertible Senior Notes Due 2023		1 Months Ended
	Jun. 05, 2019 USD ($) shares	Aug. 31, 2018 USD ($) $ / shares	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Debt Instrument [Line Items]
Debt instrument face amount		$ 65,000,000	$ 5,000,000	$ 5,000,000
Interest rate		4.00%
Debt converted	$ 60,000,000
Conversion shares (in shares) \| shares	10,801,080
Fees paid for repurchase and exchange of convertible notes	$ 6,000,000
Conversion ratio		0.1800180
Debt conversion price (in USD per share) \| $ / shares		$ 5.56
Redemption price percentage		100.00%

DEBT - Schedule of Convertible Senior Notes due 2023 (Details) - Convertible Notes - Convertible Senior Notes Due 2023 - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Contractual interest expense	$ 200	$ 200
Amortization of debt issuance costs	40	40
Total interest cost recognized	$ 240	$ 240

DEBT - Sale of Long - Term Financing Receivables (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2018
Financing Receivable \| Financing Receivable Recorded As Debt
Debt Instrument [Line Items]
Proceeds from debt, net of issuance costs	$ 2.8	$ 5.6

COMMITMENTS AND CONTINGENCIES - Narrative (Details) - USD ($)	3 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2020	Dec. 31, 2021	Mar. 26, 2020
Line of Credit Facility [Line Items]
Term of lease contract, maximum renewal term			12 years
Purchase obligation			$ 424,600,000
Operating lease, Lease not yet commenced			$ 5,600,000
Operating lease, Lease not yet commenced, term			10 years
Section 301 Tariff Refunds
Line of Credit Facility [Line Items]
Potential positive impact of approval of requested Tariff refunds				$ 38,900,000
Tariff refund	$ 14,700,000	$ 24,800,000
Tariff refund receivable		14,700,000	$ 0
Recognized in current period		38,900,000
Section 301 Tariff Refunds, Accrued Interest
Line of Credit Facility [Line Items]
Potential positive impact of approval of requested Tariff refunds				$ 600,000
Recognized in current period		$ 600,000

COMMITMENTS AND CONTINGENCIES - Lease Expense Components (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Operating lease costs	$ 7,049	$ 5,332

COMMITMENTS AND CONTINGENCIES - Lease Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Operating lease liabilities, current (Accrued liabilities)	$ 3,830	$ 4,542
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	us-gaap:AccruedLiabilitiesCurrent	us-gaap:AccruedLiabilitiesCurrent
Operating lease liabilities, non-current (Other liabilities)	$ 11,920	$ 15,209
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	us-gaap:OtherLiabilitiesNoncurrent	us-gaap:OtherLiabilitiesNoncurrent
Total operating lease liabilities	$ 15,750	$ 19,751
Weighted average remaining lease term	5 years 10 months 24 days	6 years 4 months 24 days
Weighted average discount rate	7.40%	7.70%

COMMITMENTS AND CONTINGENCIES - Supplemental Cash Flow and Other Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Operating cash flows from operating leases	$ 5,855	$ 4,762
Lease liabilities arising from obtaining right-of-use assets	$ 708	$ 10,625

COMMITMENTS AND CONTINGENCIES - Schedule of Minimum Lease Payments Under Noncancelable Operating Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2022	$ 4,771
2023	4,160
2024	3,198
2025	2,422
2026	1,395
Thereafter	2,680
Total lease payments	18,626
Less: imputed lease interest	(2,876)
Total lease liabilities	$ 15,750	$ 19,751

STOCKHOLDERS' EQUITY (Details) - USD ($)	3 Months Ended		12 Months Ended
STOCKHOLDERS' EQUITY (Details) - USD ($)	Dec. 31, 2021	Jun. 30, 2021	Dec. 31, 2021	May 31, 2021	May 19, 2021	Dec. 31, 2020	May 20, 2020	May 19, 2020	Apr. 30, 2020
Equity, Class of Treasury Stock [Line Items]
Common stock, par value (in usd per share)	$ 0.00001		$ 0.00001		$ 0.00001	$ 0.00001	$ 0.00001
Common stock, shares authorized (in shares)	300,000,000		300,000,000		300,000,000	200,000,000	200,000,000	150,000,000
Repurchase of common stock			$ 500,000,000
2020 Repurchase Program
Equity, Class of Treasury Stock [Line Items]
Repurchase program, shares authorized (in shares)									$ 200,000,000
Stock repurchased and retired during period (in shares)		1,700,000
Average cost, shares repurchased (in usd per share)		$ 117.47
Repurchase of common stock		$ 200,000,000
2021 Repurchase Program
Equity, Class of Treasury Stock [Line Items]
Repurchase program, shares authorized (in shares)				$ 500,000,000
Stock repurchased and retired during period (in shares)	1,500,000
Average cost, shares repurchased (in usd per share)	$ 196.98
Repurchase of common stock	$ 300,000,000
Repurchase program, remaining stock authorized for repurchase	$ 200,000,000		$ 200,000,000

STOCK-BASED COMPENSATION - Narrative (Details)				12 Months Ended
STOCK-BASED COMPENSATION - Narrative (Details)	Jan. 01, 2022 shares	May 18, 2017 shares	Mar. 29, 2012 shares	Dec. 31, 2021 USD ($) purchasePeriod $ / shares shares	May 19, 2021 $ / shares shares	Dec. 31, 2020 $ / shares	May 20, 2020 $ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, par value (in usd per share) \| $ / shares				$ 0.00001	$ 0.00001	$ 0.00001	$ 0.00001
Total unrecognized compensation cost \| $				$ 254,600,000
Weighted-average recognition period for unrecognized compensation cost				2 years 9 months 18 days
2011 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, shares authorized (in shares)				2,643,171
Vesting period				4 years
Share-based compensation, shares available for grant (in shares)				7,963,894
2011 Equity Incentive Plan \| Before August 1, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, weighted-average remaining contractual term				10 years
2011 Equity Incentive Plan \| After August 1, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, weighted-average remaining contractual term				7 years
2021 Plan, Newly Reserved Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Capital shares reserved for future issuance (in shares)					9,100,456
2021 Plan, Returning Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Capital shares reserved for future issuance (in shares)					5,256,517
Employee Stock Purchase Plan (ESPP)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, shares authorized (in shares)			669,603
Share-based compensation, shares available for grant (in shares)				1,754,231
Share-based compensation, evergreen shares (in shares)		700,000	330,396
Share-based compensation, increase in number of shares authorized			1.00%
Share-based compensation, additional shares authorized (in shares)		400,000
Employee stock purchase plan, number of interim purchase periods \| purchasePeriod				4
Employee stock purchase plan, offering period				24 months
Share-based compensation, maximum employee subscription rate				15.00%
Share-based compensation, purchase price of common stock percent to fair market value				85.00%
Look back feature period				2 years
General duration of employee stock purchase plan				24 months
IRS limitation for employees right to acquire class common stock under ESPP \| $				$ 25,000
Employee Stock Purchase Plan (ESPP) \| Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation, evergreen shares (in shares)	700,000

STOCK-BASED COMPENSATION - Summary of the Weighted-Average Grant Date Fair Value of Options Granted (Details) - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
The fair value of each option granted during the periods
Grants in period (in shares)	0	11,000	43,000
Stock options
The fair value of each option granted during the periods
Weighted average grant date fair value (in usd per share)		$ 38.45	$ 9.16
Expected term		3 years 9 months 18 days	3 years 9 months 18 days
Expected volatility		86.40%	89.10%
Annual risk-free rate of return		0.10%	2.10%
Dividend yield		0.00%	0.00%

STOCK-BASED COMPENSATION - Summary of Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 114,286	$ 42,503	$ 20,176
Income tax benefit included in the provision for incomes taxes	97,129	61,389	8,185
Cost of revenues
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	7,366	3,759	1,650
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	33,927	12,701	4,897
Sales and marketing
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	37,434	11,548	5,678
General and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	35,559	14,495	7,216
Restructuring
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 0	$ 0	$ 735

STOCK-BASED COMPENSATION - Summary of Stock-Based Compensation Expense Associated with Each Type of Award (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 114,286	$ 42,503	$ 20,176
Stock options, RSUs and PSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	110,142	39,841	19,216
Employee stock purchase plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 4,144	$ 2,662	$ 960

STOCK-BASED COMPENSATION - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Number of Shares Outstanding
Outstanding, beginning balance (in shares)	2,532,000	4,097,000	6,772,000
Granted (in shares)	0	11,000	43,000
Exercised (in shares)	(267,000)	(1,494,000)	(2,616,000)
Canceled (in shares)	(1,000)	(82,000)	(102,000)
Outstanding, ending balance (in shares)	2,264,000	2,532,000	4,097,000
Shares outstanding, vested and expected to vest (in shares)	2,264,000
Shares outstanding, exercisable (in shares)	2,262,000
Weighted- Average Exercise Price per Share
Outstanding, beginning balance (in usd per share)	$ 1.96	$ 2.18	$ 1.76
Granted (in usd per share)	0	64.17	14.58
Exercised (in usd per share)	2.44	2.74	1.22
Canceled (in usd per share)	0.83	6.94	4.07
Outstanding, ending balance (in usd per share)	1.90	$ 1.96	$ 2.18
Weighted-average exercise price, vested and expected (in usd per share)	1.90
Weighted-average exercise price, exercisable (in usd per share)	$ 1.90
Weighted-Average Remaining Contractual Term
Outstanding	2 years 9 months 18 days
Vested and expected to vest	2 years 9 months 18 days
Exercisable	2 years 9 months 18 days
Aggregate Intrinsic Value
Exercised	$ 42,091	$ 114,089	$ 31,093
Outstanding	409,834
Vested and expected to vest	409,834
Exercisable	$ 409,550
Share price (in usd per share)	$ 182.94

STOCK-BASED COMPENSATION - Summary of Stock Options Outstanding (Details) shares in Thousands	12 Months Ended
	Dec. 31, 2021 $ / shares shares
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Options outstanding, number of shares (shares) \| shares	2,264
Options outstanding - weighted- average remaining life	2 years 9 months 18 days
Options outstanding - weighted- average exercise price (usd per share)	$ 1.90
Options exercisable - number of shares exercisable (shares) \| shares	2,262
Options exercisable - weighted-average exercise price (usd per share)	$ 1.90
$0.70 —– $1.11
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Exercise price range, lower limit (usd per share)	0.70
Exercise price range, upper limit (usd per share)	$ 1.11
Options outstanding, number of shares (shares) \| shares	486
Options outstanding - weighted- average remaining life	3 years 3 months 18 days
Options outstanding - weighted- average exercise price (usd per share)	$ 0.86
Options exercisable - number of shares exercisable (shares) \| shares	486
Options exercisable - weighted-average exercise price (usd per share)	$ 0.85
$1.29 —– $1.29
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Exercise price range, lower limit (usd per share)	1.29
Exercise price range, upper limit (usd per share)	$ 1.29
Options outstanding, number of shares (shares) \| shares	1,000
Options outstanding - weighted- average remaining life	2 years 8 months 12 days
Options outstanding - weighted- average exercise price (usd per share)	$ 1.29
Options exercisable - number of shares exercisable (shares) \| shares	1,000
Options exercisable - weighted-average exercise price (usd per share)	$ 1.28
$1.31 —– $1.31
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Exercise price range, lower limit (usd per share)	1.31
Exercise price range, upper limit (usd per share)	$ 1.31
Options outstanding, number of shares (shares) \| shares	556
Options outstanding - weighted- average remaining life	2 years 3 months 18 days
Options outstanding - weighted- average exercise price (usd per share)	$ 1.31
Options exercisable - number of shares exercisable (shares) \| shares	556
Options exercisable - weighted-average exercise price (usd per share)	$ 1.31
$1.53 —– $14.58
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Exercise price range, lower limit (usd per share)	1.53
Exercise price range, upper limit (usd per share)	$ 14.58
Options outstanding, number of shares (shares) \| shares	211
Options outstanding - weighted- average remaining life	3 years 1 month 6 days
Options outstanding - weighted- average exercise price (usd per share)	$ 5.65
Options exercisable - number of shares exercisable (shares) \| shares	209
Options exercisable - weighted-average exercise price (usd per share)	$ 5.65
$64.17 —– $64.17
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Exercise price range, lower limit (usd per share)	64.17
Exercise price range, upper limit (usd per share)	$ 64.17
Options outstanding, number of shares (shares) \| shares	11
Options outstanding - weighted- average remaining life	5 years 4 months 24 days
Options outstanding - weighted- average exercise price (usd per share)	$ 64.17
Options exercisable - number of shares exercisable (shares) \| shares	11
Options exercisable - weighted-average exercise price (usd per share)	$ 64.17

STOCK-BASED COMPENSATION - Summary of Restricted Stock Unit Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Aggregate Intrinsic Value
Share price (in usd per share)	$ 182.94
Restricted stock units
Number of Shares Outstanding
Outstanding, beginning balance (in shares)	3,588	4,263	4,352
Granted (in shares)	1,301	1,550	2,112
Vested (in shares)	(1,979)	(2,085)	(1,707)
Canceled (in shares)	(124)	(140)	(494)
Outstanding, ending balance (in shares)	2,786	3,588	4,263
Number of shares outstanding, expected to vest (in shares)	2,786
Weighted Average Fair Value per Share at Grant Date
Outstanding, beginning balance (in usd per share)	$ 27.61	$ 7.19	$ 3.52
Granted (in usd per share)	179.88	55.66	11.50
Vested (in usd per share)	20.47	7.26	3.87
Canceled (in usd per share)	88.50	19.47	4.81
Outstanding, ending balance (in usd per share)	100.73	$ 27.61	$ 7.19
Weighted-Average Fair Value per Share at Grant Date, Expected to vest (in usd per share)	$ 100.73
Weighted-Average Remaining Contractual Term
Outstanding	1 year 2 months 12 days
Expected to vest	1 year 2 months 12 days
Aggregate Intrinsic Value
Vested	$ 364,665	$ 125,578	$ 27,156
Outstanding	509,864
Aggregate intrinsic value, expected to vest	$ 509,864

STOCK-BASED COMPENSATION - Summary of Performance Stock Unit Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Aggregate Intrinsic Value
Share price (in usd per share)	$ 182.94
Performance shares
Number of Shares Outstanding
Outstanding, beginning balance (in shares)	494	955	1,330
Granted (in shares)	715	989	1,052
Vested (in shares)	(494)	(1,450)	(1,063)
Canceled (in shares)	(270)	0	(364)
Outstanding, ending balance (in shares)	445	494	955
Weighted Average Fair Value per Share at Grant Date
Outstanding, beginning balance (in usd per share)	$ 51.10	$ 9.83	$ 4.66
Granted (in usd per share)	131.60	31.12	9.48
Vested (in usd per share)	59.19	10.20	4.62
Canceled (in usd per share)	52.75	0	5.16
Outstanding, ending balance (in usd per share)	$ 169.82	$ 51.10	$ 9.83
Weighted-Average Remaining Contractual Term
Weighted average remaining contractual term	2 months 12 days
Aggregate Intrinsic Value
Vested	$ 91,803	$ 52,144	$ 10,818
Outstanding	$ 81,456

STOCK-BASED COMPENSATION - Summary of ESPP Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Proceeds from common stock issued under ESPP	$ 6,832	$ 4,304	$ 1,692
Shares of common stock issued (shares)	235	347	315
Weighted-average price per share (usd per share)	$ 29.12	$ 12.41	$ 5.37

INCOME TAXES - Schedule of Domestic and Foreign Components of Loss before Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
United States	$ 102,886	$ 112,727	$ 85,520
Foreign	18,042	6,683	4,594
Income before income taxes	$ 120,928	$ 119,410	$ 90,114

- Definition

Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8933-108599

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8906-108599

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8933-108599

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 940
-SubTopic 20
-Section 25
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=123384075&loc=d3e41242-110953

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8736-108599

Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(10))
-URI http://asc.fasb.org/extlink&oid=123367319&loc=SL114868664-224227

Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(8))
-URI http://asc.fasb.org/extlink&oid=120400993&loc=SL114874131-224263

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 235
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-05(b)(2))
-URI http://asc.fasb.org/extlink&oid=120399901&loc=d3e537907-122884

Reference 9: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 31
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8924-108599

Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(15))
-URI http://asc.fasb.org/extlink&oid=120399700&loc=SL114874048-224260

+ Details

INCOME TAXES - Schedule of Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Current:
Federal	$ 0	$ 0	$ 0
State	488	636	327
Foreign	6,232	1,896	1,589
Total	6,720	2,532	1,916
Deferred:
Federal	(28,398)	(13,445)	(56,959)
State	(4,380)	(3,672)	(17,458)
Foreign	1,537	0	1,467
Total	(31,241)	(17,117)	(72,950)
Income tax (benefit)	$ (24,521)	$ (14,585)	$ (71,034)

INCOME TAXES - Schedule of Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Income tax (benefit) provision at statutory federal rate	$ 27,681	$ 25,076	$ 18,929
State taxes, net of federal benefit	489	(3,098)	(17,197)
Change in valuation allowance	0	0	(71,300)
Foreign tax rate and tax law differential	1,073	611	1,206
Tax credits	(15,632)	(5,835)	(1,803)
Stock-based compensation	(80,950)	(50,818)	(8,072)
Other permanent items	178	(253)	31
Other nondeductible/nontaxable items	2,316	1,525	2,765
Uncertain tax positions	6,911	1,530	504
GILTI	0	0	1,086
Section 162(m)	25,812	11,469	2,817
Convertible note settlements	8,223	0	0
Warrant mark-to-mark adjustment	(622)	5,208	0
Income tax (benefit)	$ (24,521)	$ (14,585)	$ (71,034)

INCOME TAXES - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Allowances and reserves	$ 18,764	$ 13,146
Net operating loss and tax credit carryforwards	65,699	53,116
Stock-based compensation	12,935	4,598
Deferred revenue	27,778	20,765
Fixed assets and intangibles	39,711	8,706
Sec. 163(j) interest carryforward	10,749	4,401
Other	1,609	7,007
Subtotal	177,245	111,739
Total deferred tax assets	177,245	111,739
Deferred tax liabilities:
Goodwill	(31,805)	(1,719)
Unremitted foreign earnings	(2,226)	(7)
Deferred cost of goods sold	(23,713)	(17,545)
Total deferred tax liabilities	(57,744)	(19,271)
Net deferred tax asset	$ 119,501	$ 92,468

INCOME TAXES - Narrative (Details) $ in Millions	12 Months Ended
INCOME TAXES - Narrative (Details) $ in Millions	Dec. 31, 2021 USD ($)
Operating Loss Carryforwards [Line Items]
Unrecognized tax benefits	$ 12.5
Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	153.9
Domestic Tax Authority \| Research Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Tax credit carryforward	17.3
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	92.8
State and Local Jurisdiction \| Research Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Tax credit carryforward	$ 9.8

INCOME TAXES - Schedule of Reconciliation of Total Amounts of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits—at beginning of year	$ 8,421	$ 6,589	$ 6,325
Increases in balances related to tax positions taken in prior years	4,391	0	0
Decreases in balances related to tax positions taken in prior years	0	0	(370)
Increases in balances related to tax positions taken in current year	8,301	2,006	771
Lapses in statutes of limitations	(209)	(174)	(137)
Unrecognized tax benefits—at end of year	$ 20,904	$ 8,421	$ 6,589

CONCENTRATION OF CREDIT RISK AND MAJOR CUSTOMERS (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accounts Receivable, Largest Customer \| Accounts receivable \| Credit concentration risk
Revenue, Major Customer [Line Items]
Percentage of concentration risk	38.00%
Accounts Receivable, Second Largest Customer \| Accounts receivable \| Credit concentration risk
Revenue, Major Customer [Line Items]
Percentage of concentration risk		36.00%
Net Revenues, Largest Customer \| Net revenue \| Customer concentration risk
Revenue, Major Customer [Line Items]
Percentage of concentration risk	34.00%	29.00%	21.00%
Net Revenue, Second Largest Customer \| Net revenue \| Customer concentration risk
Revenue, Major Customer [Line Items]
Percentage of concentration risk			12.00%

NET INCOME PER SHARE - Schedule of Computation of Basic and Diluted Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Numerator:
Net income	$ 145,449	$ 133,995	$ 161,148
Notes due 2023 interest and financing costs, net	177	177	1,088
Adjusted net income	$ 145,626	$ 134,172	$ 162,236
Weighted average common shares outstanding (in shares)	134,025	125,561	116,713
Denominator:
Weighted average common shares outstanding (in shares)	134,025	125,561	116,713
Employee stock-based awards (in shares)	4,918	6,997	8,964
Weighted average common shares outstanding for diluted calculation (in shares)	142,878	141,918	131,644
Net income per share, basic (in USD per share)	$ 1.09	$ 1.07	$ 1.38
Net income per share, diluted (in USD per share)	$ 1.02	$ 0.95	$ 1.23
Convertible Senior Notes Due 2024
Denominator:
Warrants (in shares)	647	4,011	0
Convertible Senior Notes Due 2025
Denominator:
Warrants (in shares)	691	0	0
Convertible Notes \| Convertible Senior Notes Due 2023
Denominator:
Notes due (in shares)	900	900	5,516
Convertible Notes \| Convertible Senior Notes Due 2024
Denominator:
Notes due (in shares)	768	4,449	451
Convertible Notes \| Convertible Senior Notes Due 2025
Denominator:
Notes due (in shares)	929	0	0

NET INCOME PER SHARE- Schedule of Potentially Dilutive Securities Excluded from the Computation of Diluted Net Income Per Share (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	6,851	1,494	485
Employee stock-based awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	32	43	185
Warrants \| Convertible Senior Notes Due 2028
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	2,184	0	0
Warrants \| Convertible Senior Notes Due 2026
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	2,225	0	0
Warrants \| Convertible Senior Notes Due 2025
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	0	1,254	0
Warrants \| Convertible Senior Notes Due 2024
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	0	0	300
Notes due \| Convertible Senior Notes Due 2028
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	1,082	0	0
Notes due \| Convertible Senior Notes Due 2026
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	1,328	0	0
Notes due \| Convertible Senior Notes Due 2025
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	0	197

NET INCOME PER SHARE - Narrative (Details) - Convertible Notes - $ / shares	Mar. 01, 2021	Mar. 09, 2020
Convertible Senior Notes Due 2025
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Debt conversion price (in USD per share)		$ 81.54
Convertible Senior Notes Due 2026
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Debt conversion price (in USD per share)	$ 307.47
Convertible Senior Notes Due 2028
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Debt conversion price (in USD per share)	$ 284.87

SEGMENT AND GEOGRAPHIC INFORMATION - Narrative (Details)	12 Months Ended
	Dec. 31, 2021 segment
Segment Reporting [Abstract]
Number of reportable segments	1
Number of operating segments	1

SEGMENT AND GEOGRAPHIC INFORMATION - Summary of Long-Lived Assets by Geographic Region (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 82,167	$ 42,985
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	37,685	19,870
India
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	17,490	4,371
China
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	12,906	9,948
Mexico
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	8,735	4,808
New Zealand
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	4,622	3,837
Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 729	$ 151

RELATED PARTY - Narrative (Details) - Convertible Notes - Convertible Senior Notes Due 2023 - USD ($)	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2018	Aug. 31, 2018
Related Party Transaction [Line Items]
Debt instrument face amount	$ 5,000,000	$ 5,000,000		$ 65,000,000
Thurman John Rodgers
Related Party Transaction [Line Items]
Debt instrument face amount	$ 5,000,000	$ 5,000,000	$ 5,000,000

Label	Element	Value
Accounting Standards Update [Extensible Enumeration]	us-gaap_AccountingStandardsUpdateExtensibleList	Accounting Standards Update 2018-07 [Member]

- Definition

Indicates amendment to accounting standards.

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+ Details