0001463101-22-000053 | 10-Q | XBRL Viewer

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COVER PAGE - shares	3 Months Ended
COVER PAGE - shares	Mar. 31, 2022	Apr. 21, 2022
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2022
Document Transition Report	false
Entity File Number	001-35480
Entity Registrant Name	Enphase Energy, Inc.
Entity Incorporation, State	DE
Entity Tax Identification Number	20-4645388
Entity Address, Address Line One	47281 Bayside Parkway
Entity Address, City or Town	Fremont
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94538
City Area Code	877
Local Phone Number	774-7000
Title of 12(b) Security	Common Stock, $0.00001 par value per share
Trading Symbol	ENPH
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		135,028,239
Entity Central Index Key	0001463101
Amendment Flag	false
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 251,850	$ 119,316
Marketable securities	811,621	897,335
Accounts receivable, net of allowances of $599 and $1,590 at March 31, 2022 and December 31, 2021, respectively	358,310	333,626
Inventory	96,436	74,400
Prepaid expenses and other assets	40,566	37,784
Total current assets	1,558,783	1,462,461
Property and equipment, net	85,073	82,167
Operating lease, right of use asset, net	19,442	14,420
Intangible assets, net	103,173	97,758
Goodwill	195,637	181,254
Other assets	120,878	118,726
Deferred tax assets, net	180,291	122,470
Total assets	2,263,277	2,079,256
Current liabilities:
Accounts payable	104,738	113,767
Accrued liabilities	169,146	157,912
Deferred revenues, current	68,693	62,670
Warranty obligations, current (includes $19,412 and $14,612 measured at fair value at March 31, 2022 and December 31, 2021, respectively)	23,960	19,395
Debt, current	87,219	86,052
Total current liabilities	453,756	439,796
Long-term liabilities:
Deferred revenues, non-current	202,711	187,186
Warranty obligations, non-current (includes $42,174 and $36,395 measured at fair value at March 31, 2022 and December 31, 2021, respectively)	59,619	53,982
Other liabilities	19,259	16,530
Debt, non-current	1,196,950	951,594
Total liabilities	1,932,295	1,649,088
Commitments and contingencies (Note 10)
Stockholders’ equity:
Common stock, $0.00001 par value, 300,000 shares authorized; and 134,959 shares and 133,894 shares issued and outstanding at March 31, 2022 and December 31, 2021, respectively	1	1
Additional paid-in capital	666,511	837,924
Accumulated deficit	(328,206)	(405,737)
Accumulated other comprehensive loss	(7,324)	(2,020)
Total stockholders’ equity	330,982	430,168
Total liabilities and stockholders’ equity	$ 2,263,277	$ 2,079,256
Common stock, shares authorized (in shares)	300,000,000	300,000,000

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Accounts receivable, allowance	$ 599	$ 1,590
Product warranty, measured at fair value, current	19,412	14,612
Product warranty, measured at fair value, noncurrent	$ 42,174	$ 36,395
Common stock, par value (in usd per share)	$ 0.00001	$ 0.00001
Common stock, shares authorized (in shares)	300,000,000	300,000,000
Common stock, shares issued (in shares)	134,959,000	133,894,000
Common stock, shares outstanding (in shares)	134,959,000	133,894,000

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Income Statement [Abstract]
Net revenues	$ 441,292	$ 301,754
Cost of revenues	264,319	178,805
Gross profit	176,973	122,949
Operating expenses:
Research and development	35,719	21,818
Sales and marketing	41,344	19,622
General and administrative	38,086	20,123
Total operating expenses	115,149	61,563
Income from operations	61,824	61,386
Other income (expense), net
Interest income	460	73
Interest expense	(2,736)	(7,329)
Other (expense) income, net	(2,141)	573
Loss on partial settlement of convertible notes	0	(56,369)
Total other expense, net	(4,417)	(63,052)
Income (loss) before income taxes	57,407	(1,666)
Income tax (provision) benefit	(5,586)	33,364
Net income	$ 51,821	$ 31,698
Net income per share:
Basic (in USD per share)	$ 0.39	$ 0.24
Diluted (in USD per share)	$ 0.37	$ 0.22
Shares used in per share calculation:
Basic (in shares)	134,327	131,303
Diluted (in shares)	144,617	146,442

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Statement of Comprehensive Income [Abstract]
Net income	$ 51,821	$ 31,698
Other comprehensive income:
Foreign currency translation adjustments	264	206
Marketable securities
Change in net unrealized loss	(5,568)	0
Less: reclassification adjustment for net losses included in net income	0	0
Net change, net of income tax benefit of $1,956	(5,568)	0
Comprehensive income	$ 46,517	$ 31,904

- 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

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) $ in Thousands	3 Months Ended
	Mar. 31, 2022 USD ($)
Statement of Comprehensive Income [Abstract]
Marketable Securities, income tax benefit	$ 1,956

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common stock and paid-in capital	Common stock and 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 at Dec. 31, 2020		$ 534,745		$ (51,186)		$ 434
Issuance of common stock from exercise of equity awards and employee stock purchase plan		214
Payment of withholding taxes related to net share settlement of equity awards		(9,185)
Equity component of convertible senior notes, net		207,962
Cost of convertible notes hedge related to the convertible senior notes, net		(213,322)
Sale of warrants related to the convertible senior notes		220,800
Equity component of settlement of convertible senior notes, net		(966,483)
Settlement of convertible senior notes		962,114
Stock-based compensation		14,844
Net income	$ 31,698			31,698
Foreign currency translation adjustments	206					206
Change in net unrealized loss on marketable securities, net of tax	0					0
Balance, end of period at Mar. 31, 2021	$ 732,841	751,689		(19,488)		640
Balance, beginning of period at Dec. 31, 2020		534,745		(51,186)		434
Accounting Standards Update [Extensible Enumeration]	Accounting Standards Update 2020-06
Balance, end of period at Dec. 31, 2021	$ 430,168	837,925	$ (207,967)	(405,737)	$ 25,710	(2,020)
Issuance of common stock from exercise of equity awards and employee stock purchase plan		404
Payment of withholding taxes related to net share settlement of equity awards		(9,344)
Stock-based compensation		45,494
Net income	51,821			51,821
Foreign currency translation adjustments	264					264
Change in net unrealized loss on marketable securities, net of tax	(5,568)					(5,568)
Balance, end of period at Mar. 31, 2022	$ 330,982	$ 666,512		$ (328,206)		$ (7,324)

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities:
Net income	$ 51,821	$ 31,698
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	15,558	5,558
Provision for doubtful accounts	147	14
Non-cash interest expense	1,979	7,156
Loss on partial settlement of convertibles notes	0	56,369
Deemed repayment of convertible notes attributable to accreted debt discount	0	(15,579)
Change in fair value of debt securities	1,116	(1,437)
Stock-based compensation	47,797	14,844
Deferred income taxes	3,165	(35,367)
Changes in operating assets and liabilities:
Accounts receivable	(24,224)	(53,719)
Inventory	(22,036)	6,888
Prepaid expenses and other assets	(3,042)	(5,040)
Accounts payable, accrued and other liabilities	(1,805)	36,376
Warranty obligations	9,906	8,640
Deferred revenues	22,061	19,440
Net cash provided by operating activities	102,443	75,841
Cash flows from investing activities:
Purchases of property and equipment	(12,375)	(9,940)
Investments in private companies	0	(25,000)
Business acquisitions, net of cash acquired	(24,625)	(55,239)
Maturities of marketable securities	76,735	0
Net cash provided by (used in) investing activities	39,735	(90,179)
Cash flows from financing activities:
Issuance of convertible notes, net of issuance costs	0	1,189,388
Purchase of convertible note hedges	0	(286,235)
Sale of warrants	0	220,800
Principal payments and financing fees on debt	0	(1,078)
Partial repurchase of convertible notes	0	(289,233)
Proceeds from exercise of equity awards and employee stock purchase plan	404	214
Payment of withholding taxes related to net share settlement of equity awards	(9,344)	(9,185)
Net cash provided by (used in) financing activities	(8,940)	824,671
Effect of exchange rate changes on cash and cash equivalents	(704)	(702)
Net increase in cash and cash equivalents	132,534	809,631
Cash and cash equivalents—Beginning of period	119,316	679,379
Cash and cash equivalents—End of period	251,850	1,489,010
Supplemental disclosures of non-cash investing and financing activities:
Purchases of property and equipment included in accounts payable	4,352	7,301
Purchase Of Property and Equipment Through Tenant Improvement Allowance	748	0
Contingent consideration in connection with the acquisition	0	3,500
Convertible senior note issuance costs included in accounts payable and accrued expense	$ 0	$ 991

DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION	3 Months Ended
DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION	Mar. 31, 2022
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 condensed consolidated financial statements are presented in accordance with accounting principles generally accepted in the United States (“GAAP”). The condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. Unaudited Interim Financial Information These accompanying unaudited condensed consolidated financial statements have been prepared pursuant to the rules and regulations of the U.S. Securities and Exchange Commission (“SEC”) for interim financial reporting. In the opinion of management, these unaudited condensed consolidated financial statements reflect all adjustments, consisting of normal recurring items, considered necessary to present fairly the Company’s financial condition, results of operations, comprehensive income, stockholders’ equity and cash flows for the interim periods indicated. The results of operations for the three months ended March 31, 2022 are not necessarily indicative of the operating results for the full year. 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 continuing COVID-19 pandemic. The year-end condensed consolidated balance sheet data was derived from audited financial statements but does not include all disclosures required by accounting principles generally accepted in the United States. The Company filed audited consolidated financial statements, which included all information and notes necessary for such a complete presentation in conjunction with its Annual Report on Form 10-K for the fiscal year ended December 31, 2021 filed with the SEC on February 11, 2022 (the “Form 10‑K”). Summary of Significant Accounting Policies There have been no changes to the Company’s significant accounting policies as described in Note 2, “Summary of Significant Accounting Policies” of the notes to consolidated financial statements included in Part II, Item 8 of the Form 10-K, other than as a result of the Company’s adoption of the new accounting guidance related to convertible senior notes, effective January 1, 2022, as discussed in “Recently Adopted Accounting Pronouncements” below. Recently Adopted Accounting Pronouncements In August 2020, the Financial Accounting Standard Board (“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)” (“ASU 2020-06”), 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 adopted ASU 2020-06 in the annual period beginning January 1, 2022, on a modified retrospective basis. Upon adoption of ASU 2020-06, the Company is no longer required to bifurcate the conversion feature related to the issuance of $575.0 million aggregate principal amount of its 0.0% convertible senior notes due 2028 (the “Notes due 2028”) and $632.5 million aggregate principal amount of its 0.0% convertible senior notes due 2026 (the “Notes due 2026”) in equity. Instead, the Company combined the previously separated equity component with the liability component, which together is now classified as debt, thereby eliminating the subsequent amortization of the debt discount. Similarly, the portion of issuance costs previously allocated to equity was reclassified to the carrying value of debt and amortized over the remaining terms of the convertible senior notes. Accordingly, the Company recorded a net decrease to additional paid-in capital by $207.9 million, net of tax to remove the equity component separately recorded for the conversion features associated with the convertible senior notes and equity component associated with the issuance costs, an increase to the carrying value of its convertible debt instrument by $244.5 million to reflect the full principal amount of the convertible senior notes outstanding net of issuance costs, a decrease to deferred tax liability of $62.3 million, and a decrease to accumulated deficit by $25.7 million, net of tax in the Company’s consolidated balance sheet with no impact on the Company’s consolidated statements of operations. Also upon adoption of ASU 2020-06, the Company is no longer utilizing the treasury stock method for earnings per share impact for 0.25% convertible senior notes due 2025 (the “Notes due 2025”), Notes due 2026 and together with the Notes due 2028 (the “Convertible Senior Notes”). Instead, the Company is applying the if-converted method when reporting the number of potentially dilutive shares of common stock as the Company may at its election, settle its Convertible Senior Notes through payment or delivery, as the case may be, in cash, shares of its common stock or a combination of cash and shares of its common stock. Further, the Company under the relevant sections of the indentures, irrevocably may elect to settle principal in cash and any excess in cash or shares of the Company’s common stock for its Convertible Senior Notes. If and when the Company makes such election, there will be no adjustment to the net income and the Company will use the average share price for the period to determine the potential number of shares to be issued based upon assumed conversion to be included in the diluted share count. Recently Issued Accounting Pronouncements Not Yet Effective 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 condensed consolidated financial statements and plans to adopt the standard effective January 1, 2023.

REVENUE RECOGNITION

3 Months Ended

Mar. 31, 2022

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:


	Three Months Ended March 31,
		2022		2021
		(In thousands)
Primary geographical markets:
U.S.		$	369,492	$	247,782




International		71,800		53,972
Total		$	441,292	$	301,754

Timing of revenue recognition:
Products delivered at a point in time		$	424,149	$	288,871
Products and services delivered over time		17,143		12,883
Total		$	441,292	$	301,754

Contract Balances

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


	March 31, 2022		December 31, 2021
	(In thousands)
Receivables	$	358,310	$	333,626

Short-term contract assets (Prepaid expenses and other assets)	24,869		23,508
Long-term contract assets (Other assets)	73,138		69,583



Short-term contract liabilities (Deferred revenues, current)	68,693		62,670
Long-term contract liabilities (Deferred revenues, non-current)	202,711		187,186

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. The Company had no asset impairment charges related to contract assets in the three months ended March 31, 2022.

Significant changes in the balances of contract assets (prepaid expenses and other assets) as of March 31, 2022 are as follows (in thousands):


Contract Assets
Contract Assets, beginning of period	$	93,091
Amount recognized	(6,419)
Increase	11,335
Contract Assets, end of period	$	98,007

Contract liabilities are recorded as deferred revenue on the accompanying condensed 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.

Significant changes in the balances of contract liabilities (deferred revenues) as of March 31, 2022 are as follows (in thousands):


Contract Liabilities
Contract Liabilities, beginning of period	$	249,856
Revenue recognized	(17,143)

Increase due to billings	38,691

Contract Liabilities, end of period	$	271,404

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:


	March 31, 2022
	(In thousands)
Fiscal year:
2022 (remaining nine months)	$	52,571
2023	62,373
2024	56,709
2025	49,491
2026	33,772
Thereafter	16,488
Total	$	271,404

- 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

OTHER FINANCIAL INFORMATION

3 Months Ended

Mar. 31, 2022

Organization, Consolidation and Presentation of Financial Statements [Abstract]

OTHER FINANCIAL INFORMATION

OTHER FINANCIAL INFORMATIONInventory

Inventory consists of the following:



	March 31, 2022		December 31, 2021
	(In thousands)
Raw materials	$	31,228	$	25,429
Finished goods	65,208		48,971
Total inventory	$	96,436	$	74,400

Accrued Liabilities

Accrued liabilities consist of the following:


	March 31, 2022		December 31, 2021
	(In thousands)
Salaries, commissions, incentive compensation and benefits	$	17,110	$	13,062
Customer rebates and sales incentives	99,302		79,038
Freight	20,105		20,522
Operating lease liabilities, current	3,722		3,830
Liability due to supply agreements	10,161		14,653
Contingent consideration	—		3,710
Post combination expense accrual	7,764		8,602

Other	10,982		14,495
Total accrued liabilities	$	169,146	$	157,912

BUSINESS COMBINATIONS

3 Months Ended

Mar. 31, 2022

Business Combination and Asset Acquisition [Abstract]

BUSINESS COMBINATIONS

Acquisition of SolarLeadFactory, LLC. (“SolarLeadFactory”)

On March 14, 2022, the Company completed the acquisition of 100% of the shares of SolarLeadFactory, a privately-held company. SolarLeadFactory provides high quality leads to solar installers. As part of the purchase price, the Company paid approximately $26.1 million in cash on March 14, 2022.

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.

In addition to the purchase price summarized above, the Company will be obligated to issue up to approximately $10.0 million in shares of common stock of the Company payable in the second quarter of 2023, subject to achievement of certain operational targets. As the additional payments require continuous employment of certain key employees of SolarLeadFactory 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):


Cash and cash equivalents	$	1,426
Net tangible assets acquired	813
Intangible assets	11,200

Goodwill	12,612
Net assets acquired	$	26,051

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 developed technology and customer relationships. Developed technology intangible is 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 relationships intangible relates to SolarLeadFactory’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	$	3,600	5
Customer relationships	7,600		5
Total identifiable intangible assets	$	11,200

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

The Company incurred and accrued costs related to acquisition of $0.4 million that were recorded in general and administrative expenses in the accompanying condensed consolidated statements of operations for the three months ended March 31, 2022.

GOODWILL AND INTANGIBLE ASSETS

3 Months Ended

Mar. 31, 2022

Goodwill and Intangible Assets Disclosure [Abstract]

GOODWILL AND INTANGIBLE ASSETS

The Company’s goodwill as of March 31, 2022 and December 31, 2021 are as follows:


Goodwill	March 31, 2022		December 31, 2021
	(In thousands)
Goodwill, beginning of period	$	181,254	$	24,783
Goodwill acquired	14,105		156,390
Currency translation adjustment	278		81
Goodwill, end of period	$	195,637	$	181,254

The Company’s purchased intangible assets as of March 31, 2022 and December 31, 2021 are as follows:


	March 31, 2022								December 31, 2021
	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	38,650		3,600		(10,823)		31,427		13,100		25,550		(8,958)		29,692
Customer relationships	41,021		7,600		(13,206)		35,415		26,421		14,600		(11,448)		29,573
Trade names	37,700		—		(1,978)		35,722		—		37,700		(93)		37,607
Order backlog	600		—		(277)		323		—		600		—		600
Total purchased intangible assets	$	118,257	$	11,200	$	(26,284)	$	103,173	$	39,807	$	78,450	$	(20,499)	$	97,758

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


	Three Months Ended March 31,
		2022		2021
		(In thousands)
Developed technology		$	1,866	$	799
Customer relationships		1,758		930
Trade names		1,885		62
Order backlog		277		—
Total amortization expense		$	5,786	$	1,791

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

The expected future amortization expense of intangible assets as of March 31, 2022 is presented below (in thousands):


	March 31, 2022

Fiscal year:
2022 (remaining nine months)	$	18,212
2023	24,096
2024	21,299
2025	19,984
2026	16,425
Thereafter	2,871
Total	$	102,887

CASH EQUIVALENTS AND MARKETABLE SECURITIES

3 Months Ended

Mar. 31, 2022

Cash and Cash Equivalents [Abstract]

CASH EQUIVALENTS AND MARKETABLE SECURITIES

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


	As of March 31, 2022
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value		Cash and Cash Equivalents		Marketable Securities
Money market funds	$	193,627	$	—	$	—	$	193,627	$	193,627	$	—
Certificate of Deposit	6,000		—		(1)		5,999		—		5,999
Commercial paper	164,243		—		(379)		163,864		—		163,864
Corporate notes and bonds	164,858		1		(2,860)		161,999		—		161,999

U.S. Government agency securities	486,902		—		(7,143)		479,759		—		479,759
Total	$	1,015,630	$	1	$	(10,383)	$	1,005,248	$	193,627	$	811,621


	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 March 31, 2022 (in thousands):


	Amortized Cost		Fair Value
Due within one year	$	692,296	$	689,588
Due within one to three years	323,334		315,660
Total	$	1,015,630	$	1,005,248

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

WARRANTY OBLIGATIONS

3 Months Ended

Mar. 31, 2022

Product Warranties Disclosures [Abstract]

WARRANTY OBLIGATIONS

The Company’s warranty activities were as follows:


	Three Months Ended March 31,
		2022		2021
		(In thousands)
Warranty obligations, beginning of period		$	73,377	$	45,913
Accruals for warranties issued during period		8,910		3,894

Changes in estimates		4,912		7,655
Settlements		(5,881)		(2,930)
Increase due to accretion expense		1,515		943

Other		746		(922)
Warranty obligations, end of period		83,579		54,553
Less: current portion		(23,960)		(14,303)
Non-current		$	59,619	$	40,250

Changes in Estimates

In the three months ended March 31, 2022, the Company recorded $4.9 million in warranty expense from change in estimates primarily related to increase in expedited freight costs and replacement costs for IQ batteries. In the three months ended March 31, 2021, the Company recorded a $6.3 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 $1.3 million in the three months ended March 31, 2021 related to unit costs for prior generation microinverter replacement mainly driven by tariffs.

FAIR VALUE MEASUREMENTS

3 Months Ended

Mar. 31, 2022

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:


	March 31, 2022						December 31, 2021
	(In thousands)
	Level 1		Level 2		Level 3		Level 1		Level 2		Level 3
Assets:
Cash and cash equivalents:
Money market funds	$	193,627	$	—	$	—	$	35,789	$	—	$	—
Certificate of deposit	—		—		—		—		6,000		—
Commercial paper	—		—		—		—		26,997		—
Corporate notes and bonds	—		—		—		—		760		—

Marketable securities:
Certificate of deposit	—		5,999		—		—		9,999		—
Commercial paper	—		163,864		—		—		188,853		—
Corporate notes and bonds	—		161,999		—		—		197,612		—
U.S. Government agencies	—		479,759		—		—		485,873		—
U.S. Treasuries	—		—		—		—		14,998		—
Other assets
Investments in debt securities	—		—		39,926		—		—		41,042

Total assets measured at fair value	$	193,627	$	811,621	$	39,926	$	35,789	$	931,092	$	41,042

Liabilities:
Accrued liabilities
Contingent consideration	$	—	$	—	$	—	$	—	$	—	$	3,710
Warranty obligations
Current	—		—		19,412		—		—		14,612
Non-current	—		—		42,174		—		—		36,395
Total warranty obligations measured at fair value	—		—		61,586		—		—		51,007
Total liabilities measured at fair value	$	—	$	—	$	61,586	$	—	$	—	$	54,717

Notes due 2028, Notes due 2026 and Notes due 2025

The Company carries the Notes due 2028 and Notes due 2026 at face value less issuance costs on its condensed consolidated balance sheets, and Notes due 2025 (as defined in Note 9, “Debt” below) at face value less unamortized discount and issuance costs, on its condensed consolidated balance sheets. The fair value of the Notes due 2028, Notes due 2026 and Notes due 2025 was $534.0 million, $592.7 million and $245.9 million, respectively, as of March 31, 2022 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.

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 condensed 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 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 condensed 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 condensed consolidated balance sheet as of March 31, 2022. The changes in the balance in investments in debt securities during the period are as follows:


	Three Months Ended March 31,
	2022		2021
	(In thousands)
Balance at beginning of period	$	41,042	$	—
Investment	—		25,000
Fair value adjustments included in other (expense) income, net	(1,116)		1,437

Balance at end of period	$	39,926	$	26,437

Contingent consideration

The estimated fair value of the contingent consideration incurred in connection with the Company’s acquisition of Sofdesk Inc. 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 condensed 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 three months ended March 31, 2022:


	Three Months Ended March 31,
	2022		2021
	(In thousands)
Balance at beginning of period	$	3,710	$	—
Addition	—		3,500
Fair value adjustments included in other income (expense), net	15		40
Paid	(3,725)		—
Balance at end of period	$	—	$	3,540

Warranty obligations.

Fair Value Option for Warranty Obligations Related to 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.


	Three Months Ended March 31,
		2022		2021
		(In thousands)
Balance at beginning of period		$	51,007	$	28,736
Accruals for warranties issued during period		8,770		3,894
Changes in estimates		3,899		2,583
Settlements		(4,056)		(1,915)
Increase due to accretion expense		1,515		943
Other		451		(922)
Balance at end of period		$	61,586	$	33,319

Quantitative and Qualitative Information about Level 3 Fair Value Measurements

As of March 31, 2022 and December 31, 2021, 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

March 31,
2022

December 31,
2021

Warranty obligations for products sold since January 1, 2014

Discounted cash flows

Profit element and risk premium

16%

15%

Credit-adjusted risk-free rate

12%

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 $0.5 million reduction of the liability. Increasing the discount rate by 100 basis points would result in a $2.8 million reduction of the liability. Decreasing the discount rate by 100 basis points would result in a $3.1 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

DEBT

3 Months Ended

Mar. 31, 2022

Debt Disclosure [Abstract]

DEBT

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


	March 31, 2022		December 31, 2021
	(In thousands)
Convertible notes
Notes due 2028	$	575,000	$	575,000
Less: unamortized debt discount	—		(143,636)
Less: unamortized debt issuance costs	(7,684)		(5,775)
Carrying amount of Notes due 2028 (1)	567,316		425,589

Notes due 2026	632,500		632,500
Less: unamortized debt discount	—		(104,755)
Less: unamortized debt issuance costs	(7,813)		(6,678)
Carrying amount of Notes due 2026 (1)	624,687		521,067

Notes due 2025	102,175		102,175
Less: unamortized debt discount	(13,535)		(14,584)
Less: unamortized debt issuance costs	(1,421)		(1,539)
Carrying amount of Notes due 2025	87,219		86,052





Notes due 2023	5,000		5,000
Less: unamortized issuance costs	(53)		(62)
Carrying amount of Notes due 2023	4,947		4,938




Total carrying amount of debt	1,284,169		1,037,646

Less: current portion of convertible notes	(87,219)		(86,052)
Debt, non-current	$	1,196,950	$	951,594

(1) The net carrying amount was increased on January 1, 2022 as a result of the adoption of ASU 2020-06. Refer to Note 2, Summary of Significant Accounting Policies, in this Quarterly Report on Form 10-Q for further information.

Convertible Senior Notes due 2028

On March 1, 2021, the Company issued $575.0 million aggregate principal amount of 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 was included in additional paid-in capital in the condensed consolidated balance sheet through December 31, 2021 and was not remeasured. The difference between the principal amount of the Notes due 2028 and the liability component (the “debt discount”) was amortized to interest expense using the effective interest method over the term of the Notes due 2028 through December 31, 2021.

Through December 31, 2021, 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 condensed 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 condensed 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.

Following the adoption of ASU 2020-06 as of January 1, 2022, the Company no longer records the conversion feature of Notes due 2028 in equity. Instead, the Company combined the previously separated equity component with the liability component, which together is now classified as debt, thereby eliminating the subsequent amortization of the debt discount as interest expense. Similarly, the portion of issuance costs previously allocated to equity was reclassified to the carrying amount of Notes due 2028 and is amortized over the remaining term of the notes. Accordingly, the Company recorded a net decrease to additional paid-in capital by approximately $117.3 million, net of tax to remove the equity component separately recorded for the conversion features associated with the Notes due 2028 and equity component associated with the issuance costs, an increase of approximately $141.3 million in the carrying value of Notes due 2028 to reflect the full principal amount of the Notes due 2028, net of issuance costs, a decrease to deferred tax liability of approximately $36.0 million, and a decrease to accumulated deficit of approximately $12.0 million, net of tax in the Company’s consolidated balance sheet with no impact on the Company’s consolidated statements of operations. As of March 31, 2022, the unamortized deferred issuance cost for the Notes due 2028 was $7.7 million on the condensed 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:


	Three Months Ended March 31,
		2022		2021
		(In thousands)

Amortization of debt discount		$	—	$	1,611
Amortization of debt issuance costs		316		79
Total interest cost recognized		$	316	$	1,690

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 2028 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 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 was included in additional paid-in capital in the condensed consolidated balance sheet through December 31, 2021 and was not remeasured. The difference between the principal amount of the Notes due 2026 and the liability component (the “debt discount”) was amortized to interest expense using the effective interest method over the term of the Notes due 2026 through December 31, 2021.

Through December 31, 2021, 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 condensed 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 condensed 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.

Following the adoption of ASU 2020-06 as of January 1, 2022, the Company no longer records the conversion feature of Notes due 2026 in equity. Instead, the Company combined the previously separated equity component with the liability component, which together is now classified as debt, thereby eliminating the subsequent amortization of the debt discount. Similarly, the portion of issuance costs previously allocated to equity was reclassified to the carrying amount debt and is amortized over the remaining term of the notes. Accordingly, the Company recorded a net decrease to additional paid-in capital by approximately $90.6 million, net of tax to remove the equity component separately recorded for the conversion features associated with the Notes due 2026 and equity component associated with the issuance costs, an increase of approximately $103.2 million in the carrying value of its Notes due 2026 to reflect the full principal amount of the Notes due 2026 outstanding net of issuance costs, a decrease to deferred tax liability of approximately $26.3 million, and a decrease to accumulated deficit of approximately $13.7 million, net of tax in the Company’s consolidated balance sheet with no impact on the Company’s consolidated statements of operations. As of March 31, 2022, the unamortized deferred issuance cost for the Notes due 2026 was $7.8 million on the condensed 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:


	Three Months Ended March 31,
		2022		2021
		(In thousands)

Amortization of debt discount		$	—	$	1,786
Amortization of debt issuance costs		485		135
Total interest cost recognized		$	485	$	1,921

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 2026 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 2026 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 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 March 31, 2022 and December 31, 2021, 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 March 31, 2022 and December 31, 2021. As a result, as of January 1, 2022, the Notes due 2025 are convertible at the holders’ option through June 30, 2022. Accordingly, the Company classified the net carrying amount of the Notes due 2025 of $87.2 million and $86.1 million as Debt, current on the condensed consolidated balance sheet as of March 31, 2022 and December 31, 2021, respectively. From April 1, 2022 through the date this Quarterly Report on Form 10-Q 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 (the “2025 Warrants”) 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 condensed 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 condensed 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 condensed 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 condensed 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 three months ended March 31, 2022, 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 three months ended March 31, 2022, 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 March 31, 2022, $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:



	Three Months Ended March 31,
		2022		2021
		(In thousands)
Contractual interest expense		$	64	$	150
Amortization of debt discount		1,049		2,389
Amortization of debt issuance costs		118		294
Total interest cost recognized		$	1,231	$	2,833

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 $13.5 million as of March 31, 2022, and will be amortized over approximately 2.9 years from March 31, 2022.

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 whereby the Company sold the 2025 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 March 31, 2022, 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 2025 Warrants liability, respectively, in the condensed consolidated balance sheet and the change in fair value of derivatives was included in other expense, net in the condensed 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 the 2025 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 condensed 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 the 2025 Warrants liability were recorded in other expense, net in the condensed consolidated statements of operations during the three months ended March 31, 2021.

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 March 31, 2022 and December 31, 2021, $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.



	Three Months Ended March 31,
		2022		2021
		(In thousands)
Contractual interest expense		$	50	$	50

Amortization of debt issuance costs		10		10
Total interest costs recognized		$	60	$	60

COMMITMENTS AND CONTINGENCIES

3 Months Ended

Mar. 31, 2022

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:


	Three Months Ended March 31,
		2022		2021
		(In thousands)
Operating lease costs		$	1,937	$	1,631

The components of lease liabilities are presented as follows:


	March 31, 2022		December 31, 2021
	(In thousands except years and percentage data)
Operating lease liabilities, current (Accrued liabilities)	$	3,722	$	3,830
Operating lease liabilities, non-current (Other liabilities)	17,591		11,920
Total operating lease liabilities	$	21,313	$	15,750

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

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


	Three Months Ended March 31,
		2022		2021
		(In thousands)
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases		$	1,518	$	1,361

Non-cash investing activities:
Lease liabilities arising from obtaining right-of-use assets		$	6,742	$	—

Undiscounted cash flows of operating lease liabilities as of March 31, 2022 are as follows:


	Lease Amounts
	(In thousands)
Year:
2022 (remaining nine months)	$	3,815
2023	5,262
2024	4,362
2025	3,632
2026	2,637
Thereafter	5,845
Total lease payments	25,553
Less: imputed lease interest	(4,240)
Total lease liabilities	$	21,313

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 March 31, 2022, these purchase obligations totaled approximately $398.6 million.

Litigation

From time-to-time, the Company may be involved in litigation relating to claims arising out of its operations, the ultimate disposition of which could have a material adverse effect on its operations, financial condition or cash flows. The Company is not currently involved in any material legal proceedings; however, the Company may be involved in material legal proceedings in the future. Such matters are subject to uncertainty and there can be no assurance that such legal proceedings will not have a material effect on its business, results of operations, financial position or cash flows.

STOCK-BASED COMPENSATION

3 Months Ended

Mar. 31, 2022

Share-based Payment Arrangement [Abstract]

STOCK-BASED COMPENSATION

Stock-based Compensation Expense

Stock-based compensation expense for all stock-based awards, which includes stock options, restricted stock units (“RSUs”) and performance-based stock units (“PSUs”), expected to vest is measured at fair value on the date of grant and recognized ratably over the requisite service period.

In addition, as part of certain business acquisitions, the Company is obligated to issue shares of common stock of the Company as payment subject to achievement of certain targets. For such payments, the Company records stock-based compensation classified as post-combination expense ratably over the measurement period presuming the targets will be met.

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


	Three Months Ended March 31,
		2022		2021
		(In thousands)
Cost of revenues		$	2,507	$	982
Research and development		13,729		5,749
Sales and marketing		13,057		3,537
General and administrative		18,504		4,576

Total		$	47,797	$	14,844

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


	Three Months Ended March 31,
		2022		2021
		(In thousands)
Stock options, RSUs and PSUs		$	44,112	$	13,840
Employee stock purchase plan		1,382		1,004
Post combination expense accrual (Accrued liabilities)		2,303		—
Total		$	47,797	$	14,844

As of March 31, 2022, there was approximately $231.2 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 2.9 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, 2021	2,264	$	1.90
Granted	—	—
Exercised	(194)	2.09			$	42,091
Canceled	—	—
Outstanding at March 31, 2022	2,070	$	1.89	2.6	$	413,757
Vested and expected to vest at March 31, 2022	2,070	$	1.89	2.6	$	413,757
Exercisable at March 31, 2022	2,070	$	1.89	2.6	$	413,757

(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 March 31, 2022 is based on the closing price of the last trading day during the period ended March 31, 2022. The Company’s stock fair value used in this computation was $201.78 per share.

The following table summarizes information about stock options outstanding at March 31, 2022.


	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	3.1	$	0.85	486	$	0.85
$1.29 —– $1.29	1,000	2.5	1.29		1,000	1.29
$1.31 —– $1.90	422	2.0	1.33		422	1.33
$1.92 —– $14.58	151	3.1	6.30		151	6.30
$64.17 —– $64.17	11	5.1	64.17		11	64.17
Total	2,070	2.6	$	1.89	2,070	$	1.89

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, 2021	2,786	$	100.73
Granted	153	150.81
Vested	(639)	70.19			$	102,631
Canceled	(43)	120.94
Outstanding at March 31, 2022	2,257	112.40		1.3	$	455,509
Expected to vest at March 31, 2022	2,257	$	112.40	1.3	$	455,509

(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 March 31, 2022 is based on the closing price of the last trading day during the period ended March 31, 2022. The Company’s stock fair value used in this computation was $201.78 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, 2021	445	$	169.82
Granted	27	160.09
Vested	(303)	168.88			$	51,393
Canceled	(169)	169.93
Outstanding at March 31, 2022	—	$	—	0.0	$	—

(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 March 31, 2022 is based on the closing price of the last trading day during the period ended March 31, 2022. The Company’s stock fair value used in this computation was $201.78 per share.

INCOME TAXES	3 Months Ended
INCOME TAXES	Mar. 31, 2022
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES For the three months ended March 31, 2022, the Company’s income tax provision of $5.6 million on a net income before income taxes of $57.4 million was calculated using the annualized effective tax rate method and was primarily due to projected tax expense in the U.S. and foreign jurisdictions that are profitable, partially offset by tax deduction from employee stock compensation as a discrete event. For the three months ended March 31, 2021, the Company’s income tax benefit of $33.4 million on a net loss before income taxes of $1.7 million was calculated using the annualized effective tax rate method and was primarily due to tax deduction from employee stock compensation as a discrete event, partially offset by projected tax expense in the U.S. and foreign jurisdictions that are profitable. For the three months ended March 31, 2022 and 2021, in accordance with FASB guidance for interim reporting of income tax, the Company has computed its benefit (provision) for income taxes based on a projected annual effective tax rate while excluding loss jurisdictions which cannot be benefited.

- 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

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 11.C)
-URI http://asc.fasb.org/extlink&oid=122134291&loc=d3e330215-122817

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 17
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32809-109319

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I.5.Q1)
-URI http://asc.fasb.org/extlink&oid=122134291&loc=d3e330036-122817

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32705-109319

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 270
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6424409&loc=d3e44925-109338

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-URI http://asc.fasb.org/topic&trid=2144680

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6424122&loc=d3e41874-109331

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(2))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

+ Details

NET INCOME PER SHARE

3 Months Ended

Mar. 31, 2022

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 2011 Employee Stock Purchase Plan, the Notes due 2023, 1.0% convertible senior notes due 2024 (the “Notes due 2024”), Notes due 2025, Notes due 2026, Notes due 2028, and warrant transactions in connection with the offering of the Notes due 2024 (the “2024 Warrants”), 2025 Warrants, 2026 Warrants and the 2028 Warrants. See Note 9, “Debt,” for additional information about the Company’s outstanding notes.

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


	Three Months Ended March 31,
		2022		2021
		(In thousands, except per share data)
Numerator:
Net income		$	51,821	$	31,698


Convertible Senior Notes interest and financing costs, net		1,559		44
Adjusted net income		$	53,380	$	31,742

Denominator:
Shares used in basic per share amounts:
Weighted average common shares outstanding		134,327		131,303

Shares used in diluted per share amounts:
Weighted average common shares outstanding		134,327		131,303
Effect of dilutive securities:
Employee stock-based awards		3,661		5,735
Notes due 2023		900		900
Notes due 2024		—		2,984
2024 Warrants		—		2,506
Notes due 2025		1,253		1,713
2025 Warrants		401		1,301
Notes due 2026		2,057		—

Notes due 2028		2,018		—

Weighted average common shares outstanding for diluted calculation		144,617		146,442

Basic and diluted net income per share
Net income per share, basic		$	0.39	$	0.24
Net income per share, diluted		$	0.37	$	0.22

For the three months ended March 31, 2022, 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 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.

For the three months ended March 31, 2022, due to adoption of ASU 2020-06 on January 1, 2022, the Company is no longer utilizing the treasury stock method for earnings per share impact for the Notes due 2025, Notes due 2026 and Notes due 2028. Instead, the Company is applying the if-converted method when reporting the number of potentially dilutive shares of common stock as the Company may at its election, settle its Convertible Senior Notes through payment or delivery, as the case may be, in cash, shares of its common stock or a combination of cash and shares of its common stock. Under this method, diluted earnings per share is determined by assuming that all of the Convertible Senior Notes were converted into shares of the Company’s common stock at the beginning of the reporting period.

Further, the Company under the relevant sections of the indentures, irrevocably may elect to settle principal in cash and any excess in cash or shares of the Company’s common stock for its Notes due 2025, Notes due 2026 and Notes due 2028. If and when the Company makes such election, there will be no adjustment to the net income and the Company will use the average share price for the period to determine the potential number of shares to be issued based upon assumed conversion to be included in the diluted share count.

For the three months ended March 31, 2021, 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 2024 Warrants, the Notes due 2025, the 2025 Warrants, the Notes due 2026, the 2026 Warrants, the Notes due 2028 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 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.


	Three Months Ended March 31,
		2022	2021
		(In thousands)



Employee stock-based awards		359	54
Notes due 2028		—	569
2028 Warrants		3,093	1,070
Notes due 2026		—	682
2026 Warrants		3,152	1,070







Total		6,604	3,445

RELATED PARTY	3 Months Ended
RELATED PARTY	Mar. 31, 2022
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 March 31, 2022 and December 31, 2021, $5.0 million aggregate principal amount of the Notes due 2023 were outstanding. For additional information related to this purchase, see Note 9, “Debt,” for additional information related to this purchase.

DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION (Policies)	3 Months Ended
	Mar. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Consolidation	Basis of Presentation and Consolidation The accompanying condensed consolidated financial statements are presented in accordance with accounting principles generally accepted in the United States (“GAAP”). The condensed 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 continuing COVID-19 pandemic.
Recently Adopted Accounting Pronouncements and Recently Issued Accounting Pronouncements Not Yet Effective	Recently Adopted Accounting Pronouncements In August 2020, the Financial Accounting Standard Board (“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)” (“ASU 2020-06”), 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 adopted ASU 2020-06 in the annual period beginning January 1, 2022, on a modified retrospective basis. Upon adoption of ASU 2020-06, the Company is no longer required to bifurcate the conversion feature related to the issuance of $575.0 million aggregate principal amount of its 0.0% convertible senior notes due 2028 (the “Notes due 2028”) and $632.5 million aggregate principal amount of its 0.0% convertible senior notes due 2026 (the “Notes due 2026”) in equity. Instead, the Company combined the previously separated equity component with the liability component, which together is now classified as debt, thereby eliminating the subsequent amortization of the debt discount. Similarly, the portion of issuance costs previously allocated to equity was reclassified to the carrying value of debt and amortized over the remaining terms of the convertible senior notes. Accordingly, the Company recorded a net decrease to additional paid-in capital by $207.9 million, net of tax to remove the equity component separately recorded for the conversion features associated with the convertible senior notes and equity component associated with the issuance costs, an increase to the carrying value of its convertible debt instrument by $244.5 million to reflect the full principal amount of the convertible senior notes outstanding net of issuance costs, a decrease to deferred tax liability of $62.3 million, and a decrease to accumulated deficit by $25.7 million, net of tax in the Company’s consolidated balance sheet with no impact on the Company’s consolidated statements of operations. Also upon adoption of ASU 2020-06, the Company is no longer utilizing the treasury stock method for earnings per share impact for 0.25% convertible senior notes due 2025 (the “Notes due 2025”), Notes due 2026 and together with the Notes due 2028 (the “Convertible Senior Notes”). Instead, the Company is applying the if-converted method when reporting the number of potentially dilutive shares of common stock as the Company may at its election, settle its Convertible Senior Notes through payment or delivery, as the case may be, in cash, shares of its common stock or a combination of cash and shares of its common stock. Further, the Company under the relevant sections of the indentures, irrevocably may elect to settle principal in cash and any excess in cash or shares of the Company’s common stock for its Convertible Senior Notes. If and when the Company makes such election, there will be no adjustment to the net income and the Company will use the average share price for the period to determine the potential number of shares to be issued based upon assumed conversion to be included in the diluted share count. Recently Issued Accounting Pronouncements Not Yet Effective 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 condensed 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 2011 Employee Stock Purchase Plan, the Notes due 2023, 1.0% convertible senior notes due 2024 (the “Notes due 2024”), Notes due 2025, Notes due 2026, Notes due 2028, and warrant transactions in connection with the offering of the Notes due 2024 (the “2024 Warrants”), 2025 Warrants, 2026 Warrants and the 2028 Warrants. See Note 9, “Debt,” for additional information about the Company’s outstanding notes.

REVENUE RECOGNITION (Tables)

3 Months Ended

Mar. 31, 2022

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:


	Three Months Ended March 31,
		2022		2021
		(In thousands)
Primary geographical markets:
U.S.		$	369,492	$	247,782




International		71,800		53,972
Total		$	441,292	$	301,754

Timing of revenue recognition:
Products delivered at a point in time		$	424,149	$	288,871
Products and services delivered over time		17,143		12,883
Total		$	441,292	$	301,754

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:


	March 31, 2022		December 31, 2021
	(In thousands)
Receivables	$	358,310	$	333,626

Short-term contract assets (Prepaid expenses and other assets)	24,869		23,508
Long-term contract assets (Other assets)	73,138		69,583



Short-term contract liabilities (Deferred revenues, current)	68,693		62,670
Long-term contract liabilities (Deferred revenues, non-current)	202,711		187,186

Significant changes in the balances of contract assets (prepaid expenses and other assets) as of March 31, 2022 are as follows (in thousands):


Contract Assets
Contract Assets, beginning of period	$	93,091
Amount recognized	(6,419)
Increase	11,335
Contract Assets, end of period	$	98,007

Significant changes in the balances of contract liabilities (deferred revenues) as of March 31, 2022 are as follows (in thousands):


Contract Liabilities
Contract Liabilities, beginning of period	$	249,856
Revenue recognized	(17,143)

Increase due to billings	38,691

Contract Liabilities, end of period	$	271,404

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:


	March 31, 2022
	(In thousands)
Fiscal year:
2022 (remaining nine months)	$	52,571
2023	62,373
2024	56,709
2025	49,491
2026	33,772
Thereafter	16,488
Total	$	271,404

OTHER FINANCIAL INFORMATION (Tables)

3 Months Ended

Mar. 31, 2022

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Summary of Inventory

Inventory consists of the following:



	March 31, 2022		December 31, 2021
	(In thousands)
Raw materials	$	31,228	$	25,429
Finished goods	65,208		48,971
Total inventory	$	96,436	$	74,400

Schedule of Accrued Liabilities

Accrued liabilities consist of the following:


	March 31, 2022		December 31, 2021
	(In thousands)
Salaries, commissions, incentive compensation and benefits	$	17,110	$	13,062
Customer rebates and sales incentives	99,302		79,038
Freight	20,105		20,522
Operating lease liabilities, current	3,722		3,830
Liability due to supply agreements	10,161		14,653
Contingent consideration	—		3,710
Post combination expense accrual	7,764		8,602

Other	10,982		14,495
Total accrued liabilities	$	169,146	$	157,912

BUSINESS COMBINATION (Tables)

3 Months Ended

Mar. 31, 2022

Business Combination and Asset Acquisition [Abstract]

Summary of fair values of assets acquired and liabilities assumed


Cash and cash equivalents	$	1,426
Net tangible assets acquired	813
Intangible assets	11,200

Goodwill	12,612
Net assets acquired	$	26,051

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)
Developed technology	$	3,600	5
Customer relationships	7,600		5
Total identifiable intangible assets	$	11,200

GOODWILL AND INTANGIBLE ASSETS (Tables)

3 Months Ended

Mar. 31, 2022

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Goodwill

The Company’s goodwill as of March 31, 2022 and December 31, 2021 are as follows:


Goodwill	March 31, 2022		December 31, 2021
	(In thousands)
Goodwill, beginning of period	$	181,254	$	24,783
Goodwill acquired	14,105		156,390
Currency translation adjustment	278		81
Goodwill, end of period	$	195,637	$	181,254

Schedule of Acquired Indefinite-lived Intangible Assets by Major Class

The Company’s purchased intangible assets as of March 31, 2022 and December 31, 2021 are as follows:


	March 31, 2022								December 31, 2021
	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	38,650		3,600		(10,823)		31,427		13,100		25,550		(8,958)		29,692
Customer relationships	41,021		7,600		(13,206)		35,415		26,421		14,600		(11,448)		29,573
Trade names	37,700		—		(1,978)		35,722		—		37,700		(93)		37,607
Order backlog	600		—		(277)		323		—		600		—		600
Total purchased intangible assets	$	118,257	$	11,200	$	(26,284)	$	103,173	$	39,807	$	78,450	$	(20,499)	$	97,758

Schedule of Acquired Finite-Lived Intangible Assets by Major Class

The Company’s purchased intangible assets as of March 31, 2022 and December 31, 2021 are as follows:


	March 31, 2022								December 31, 2021
	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	38,650		3,600		(10,823)		31,427		13,100		25,550		(8,958)		29,692
Customer relationships	41,021		7,600		(13,206)		35,415		26,421		14,600		(11,448)		29,573
Trade names	37,700		—		(1,978)		35,722		—		37,700		(93)		37,607
Order backlog	600		—		(277)		323		—		600		—		600
Total purchased intangible assets	$	118,257	$	11,200	$	(26,284)	$	103,173	$	39,807	$	78,450	$	(20,499)	$	97,758

Schedule of Amortization Expense

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


	Three Months Ended March 31,
		2022		2021
		(In thousands)
Developed technology		$	1,866	$	799
Customer relationships		1,758		930
Trade names		1,885		62
Order backlog		277		—
Total amortization expense		$	5,786	$	1,791

The expected future amortization expense of intangible assets as of March 31, 2022 is presented below (in thousands):


	March 31, 2022

Fiscal year:
2022 (remaining nine months)	$	18,212
2023	24,096
2024	21,299
2025	19,984
2026	16,425
Thereafter	2,871
Total	$	102,887

CASH EQUIVALENTS AND MARKETABLE SECURITIES (Tables)

3 Months Ended

Mar. 31, 2022

Cash and Cash Equivalents [Abstract]

Debt Securities, Available-for-sale

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


	As of March 31, 2022
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value		Cash and Cash Equivalents		Marketable Securities
Money market funds	$	193,627	$	—	$	—	$	193,627	$	193,627	$	—
Certificate of Deposit	6,000		—		(1)		5,999		—		5,999
Commercial paper	164,243		—		(379)		163,864		—		163,864
Corporate notes and bonds	164,858		1		(2,860)		161,999		—		161,999

U.S. Government agency securities	486,902		—		(7,143)		479,759		—		479,759
Total	$	1,015,630	$	1	$	(10,383)	$	1,005,248	$	193,627	$	811,621


	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 March 31, 2022 (in thousands):


	Amortized Cost		Fair Value
Due within one year	$	692,296	$	689,588
Due within one to three years	323,334		315,660
Total	$	1,015,630	$	1,005,248

WARRANTY OBLIGATIONS (Tables)

3 Months Ended

Mar. 31, 2022

Product Warranties Disclosures [Abstract]

Summary of Warranty Activities

The Company’s warranty activities were as follows:


	Three Months Ended March 31,
		2022		2021
		(In thousands)
Warranty obligations, beginning of period		$	73,377	$	45,913
Accruals for warranties issued during period		8,910		3,894

Changes in estimates		4,912		7,655
Settlements		(5,881)		(2,930)
Increase due to accretion expense		1,515		943

Other		746		(922)
Warranty obligations, end of period		83,579		54,553
Less: current portion		(23,960)		(14,303)
Non-current		$	59,619	$	40,250

FAIR VALUE MEASUREMENTS (Tables)

3 Months Ended

Mar. 31, 2022

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:


	March 31, 2022						December 31, 2021
	(In thousands)
	Level 1		Level 2		Level 3		Level 1		Level 2		Level 3
Assets:
Cash and cash equivalents:
Money market funds	$	193,627	$	—	$	—	$	35,789	$	—	$	—
Certificate of deposit	—		—		—		—		6,000		—
Commercial paper	—		—		—		—		26,997		—
Corporate notes and bonds	—		—		—		—		760		—

Marketable securities:
Certificate of deposit	—		5,999		—		—		9,999		—
Commercial paper	—		163,864		—		—		188,853		—
Corporate notes and bonds	—		161,999		—		—		197,612		—
U.S. Government agencies	—		479,759		—		—		485,873		—
U.S. Treasuries	—		—		—		—		14,998		—
Other assets
Investments in debt securities	—		—		39,926		—		—		41,042

Total assets measured at fair value	$	193,627	$	811,621	$	39,926	$	35,789	$	931,092	$	41,042

Liabilities:
Accrued liabilities
Contingent consideration	$	—	$	—	$	—	$	—	$	—	$	3,710
Warranty obligations
Current	—		—		19,412		—		—		14,612
Non-current	—		—		42,174		—		—		36,395
Total warranty obligations measured at fair value	—		—		61,586		—		—		51,007
Total liabilities measured at fair value	$	—	$	—	$	61,586	$	—	$	—	$	54,717

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:


	Three Months Ended March 31,
	2022		2021
	(In thousands)
Balance at beginning of period	$	41,042	$	—
Investment	—		25,000
Fair value adjustments included in other (expense) income, net	(1,116)		1,437

Balance at end of period	$	39,926	$	26,437

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 three months ended March 31, 2022:


	Three Months Ended March 31,
	2022		2021
	(In thousands)
Balance at beginning of period	$	3,710	$	—
Addition	—		3,500
Fair value adjustments included in other income (expense), net	15		40
Paid	(3,725)		—
Balance at end of period	$	—	$	3,540


	Three Months Ended March 31,
		2022		2021
		(In thousands)
Balance at beginning of period		$	51,007	$	28,736
Accruals for warranties issued during period		8,770		3,894
Changes in estimates		3,899		2,583
Settlements		(4,056)		(1,915)
Increase due to accretion expense		1,515		943
Other		451		(922)
Balance at end of period		$	61,586	$	33,319

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

As of March 31, 2022 and December 31, 2021, 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

March 31,
2022

December 31,
2021

Warranty obligations for products sold since January 1, 2014

Discounted cash flows

Profit element and risk premium

16%

15%

Credit-adjusted risk-free rate

12%

DEBT (Tables)

3 Months Ended

Mar. 31, 2022

Debt Disclosure [Abstract]

Schedule of Debt

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


	March 31, 2022		December 31, 2021
	(In thousands)
Convertible notes
Notes due 2028	$	575,000	$	575,000
Less: unamortized debt discount	—		(143,636)
Less: unamortized debt issuance costs	(7,684)		(5,775)
Carrying amount of Notes due 2028 (1)	567,316		425,589

Notes due 2026	632,500		632,500
Less: unamortized debt discount	—		(104,755)
Less: unamortized debt issuance costs	(7,813)		(6,678)
Carrying amount of Notes due 2026 (1)	624,687		521,067

Notes due 2025	102,175		102,175
Less: unamortized debt discount	(13,535)		(14,584)
Less: unamortized debt issuance costs	(1,421)		(1,539)
Carrying amount of Notes due 2025	87,219		86,052





Notes due 2023	5,000		5,000
Less: unamortized issuance costs	(53)		(62)
Carrying amount of Notes due 2023	4,947		4,938




Total carrying amount of debt	1,284,169		1,037,646

Less: current portion of convertible notes	(87,219)		(86,052)
Debt, non-current	$	1,196,950	$	951,594

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


	Three Months Ended March 31,
		2022		2021
		(In thousands)

Amortization of debt discount		$	—	$	1,611
Amortization of debt issuance costs		316		79
Total interest cost recognized		$	316	$	1,690

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


	Three Months Ended March 31,
		2022		2021
		(In thousands)

Amortization of debt discount		$	—	$	1,786
Amortization of debt issuance costs		485		135
Total interest cost recognized		$	485	$	1,921

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



	Three Months Ended March 31,
		2022		2021
		(In thousands)
Contractual interest expense		$	64	$	150
Amortization of debt discount		1,049		2,389
Amortization of debt issuance costs		118		294
Total interest cost recognized		$	1,231	$	2,833

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.



	Three Months Ended March 31,
		2022		2021
		(In thousands)
Contractual interest expense		$	50	$	50

Amortization of debt issuance costs		10		10
Total interest costs recognized		$	60	$	60

COMMITMENTS AND CONTINGENCIES (Tables)

3 Months Ended

Mar. 31, 2022

Commitments and Contingencies Disclosure [Abstract]

Components of Lease

The components of lease expense are presented as follows:


	Three Months Ended March 31,
		2022		2021
		(In thousands)
Operating lease costs		$	1,937	$	1,631

The components of lease liabilities are presented as follows:


	March 31, 2022		December 31, 2021
	(In thousands except years and percentage data)
Operating lease liabilities, current (Accrued liabilities)	$	3,722	$	3,830
Operating lease liabilities, non-current (Other liabilities)	17,591		11,920
Total operating lease liabilities	$	21,313	$	15,750

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

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


	Three Months Ended March 31,
		2022		2021
		(In thousands)
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases		$	1,518	$	1,361

Non-cash investing activities:
Lease liabilities arising from obtaining right-of-use assets		$	6,742	$	—

Schedule of Future Minimum Rental Payments for Operating Leases

Undiscounted cash flows of operating lease liabilities as of March 31, 2022 are as follows:


	Lease Amounts
	(In thousands)
Year:
2022 (remaining nine months)	$	3,815
2023	5,262
2024	4,362
2025	3,632
2026	2,637
Thereafter	5,845
Total lease payments	25,553
Less: imputed lease interest	(4,240)
Total lease liabilities	$	21,313

STOCK-BASED COMPENSATION (Tables)

3 Months Ended

Mar. 31, 2022

Share-based Payment Arrangement [Abstract]

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 condensed consolidated statements of operations for the periods presented.


	Three Months Ended March 31,
		2022		2021
		(In thousands)
Cost of revenues		$	2,507	$	982
Research and development		13,729		5,749
Sales and marketing		13,057		3,537
General and administrative		18,504		4,576

Total		$	47,797	$	14,844

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.


	Three Months Ended March 31,
		2022		2021
		(In thousands)
Stock options, RSUs and PSUs		$	44,112	$	13,840
Employee stock purchase plan		1,382		1,004
Post combination expense accrual (Accrued liabilities)		2,303		—
Total		$	47,797	$	14,844

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, 2021	2,264	$	1.90
Granted	—	—
Exercised	(194)	2.09			$	42,091
Canceled	—	—
Outstanding at March 31, 2022	2,070	$	1.89	2.6	$	413,757
Vested and expected to vest at March 31, 2022	2,070	$	1.89	2.6	$	413,757
Exercisable at March 31, 2022	2,070	$	1.89	2.6	$	413,757

Summary of Stock Option Outstanding

The following table summarizes information about stock options outstanding at March 31, 2022.


	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	3.1	$	0.85	486	$	0.85
$1.29 —– $1.29	1,000	2.5	1.29		1,000	1.29
$1.31 —– $1.90	422	2.0	1.33		422	1.33
$1.92 —– $14.58	151	3.1	6.30		151	6.30
$64.17 —– $64.17	11	5.1	64.17		11	64.17
Total	2,070	2.6	$	1.89	2,070	$	1.89

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, 2021	2,786	$	100.73
Granted	153	150.81
Vested	(639)	70.19			$	102,631
Canceled	(43)	120.94
Outstanding at March 31, 2022	2,257	112.40		1.3	$	455,509
Expected to vest at March 31, 2022	2,257	$	112.40	1.3	$	455,509

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, 2021	445	$	169.82
Granted	27	160.09
Vested	(303)	168.88			$	51,393
Canceled	(169)	169.93
Outstanding at March 31, 2022	—	$	—	0.0	$	—

NET INCOME PER SHARE (Tables)

3 Months Ended

Mar. 31, 2022

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.


	Three Months Ended March 31,
		2022		2021
		(In thousands, except per share data)
Numerator:
Net income		$	51,821	$	31,698


Convertible Senior Notes interest and financing costs, net		1,559		44
Adjusted net income		$	53,380	$	31,742

Denominator:
Shares used in basic per share amounts:
Weighted average common shares outstanding		134,327		131,303

Shares used in diluted per share amounts:
Weighted average common shares outstanding		134,327		131,303
Effect of dilutive securities:
Employee stock-based awards		3,661		5,735
Notes due 2023		900		900
Notes due 2024		—		2,984
2024 Warrants		—		2,506
Notes due 2025		1,253		1,713
2025 Warrants		401		1,301
Notes due 2026		2,057		—

Notes due 2028		2,018		—

Weighted average common shares outstanding for diluted calculation		144,617		146,442

Basic and diluted net income per share
Net income per share, basic		$	0.39	$	0.24
Net income per share, diluted		$	0.37	$	0.22

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


	Three Months Ended March 31,
		2022	2021
		(In thousands)



Employee stock-based awards		359	54
Notes due 2028		—	569
2028 Warrants		3,093	1,070
Notes due 2026		—	682
2026 Warrants		3,152	1,070







Total		6,604	3,445

DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION (Details) - USD ($)	Mar. 31, 2022	Jan. 01, 2022	Dec. 31, 2021	Mar. 12, 2021	Mar. 01, 2021	Mar. 09, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Additional paid in capital	$ (666,511,000)		$ (837,924,000)
Accumulated deficit	$ 328,206,000		$ 405,737,000
Notes due 2028 \| Convertible Notes
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt instrument face amount					$ 575,000,000
Interest rate					0.00%
Total Convertible Senior Notes Due 2026 \| Convertible Notes
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt instrument face amount				$ 632,500,000
Notes due 2025 \| Convertible Notes
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt instrument face amount						$ 320,000,000
Interest rate	1.00%					0.25%
Cumulative Effect, Period of Adoption, Adjustment \| Accounting Standards Update 2020-06
New Accounting Pronouncements or Change in Accounting Principle [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
Cumulative Effect, Period of Adoption, Adjustment \| Accounting Standards Update 2020-06 \| Notes due 2028
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Additional paid in capital		117,300,000
Convertible debt		141,300,000
Deferred income tax liabilities		36,000,000
Accumulated deficit		$ 12,000,000

REVENUE RECOGNITION - Summary of Disaggregated Revenue by Primary Geographical Market and Timing of Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenues	$ 441,292	$ 301,754
Products delivered at a point in time
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenues	424,149	288,871
Products and services delivered over time
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenues	17,143	12,883
U.S.
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenues	369,492	247,782
International
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenues	$ 71,800	$ 53,972

- 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	Mar. 31, 2022	Dec. 31, 2021
Revenue from Contract with Customer [Abstract]
Receivables	$ 358,310	$ 333,626
Short-term contract assets (Prepaid expenses and other assets)	24,869	23,508
Long-term contract assets (Other assets)	73,138	69,583
Short-term contract liabilities (Deferred revenues, current)	68,693	62,670
Long-term contract liabilities (Deferred revenues, non-current)	$ 202,711	$ 187,186

REVENUE RECOGNITION - Narrative (Details)	3 Months Ended
REVENUE RECOGNITION - Narrative (Details)	Mar. 31, 2022 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	3 Months Ended
	Mar. 31, 2022 USD ($)
Contract Assets
Balance, beginning of period	$ 93,091
Amount recognized	(6,419)
Increase	11,335
Balance, end of period	98,007
Contract Liabilities
Balance, beginning of period	249,856
Revenue recognized	(17,143)
Increase due to billings	38,691
Balance, end of period	$ 271,404

REVENUE RECOGNITION - Summary of Estimated Revenue Expected to be Recognized in Future Periods (Details) $ in Thousands	Mar. 31, 2022 USD ($)
Revenue from Contract with Customer [Abstract]
Total estimated revenue expected to be recognized in future periods	$ 271,404
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-04-01
Revenue from Contract with Customer [Abstract]
Total estimated revenue expected to be recognized in future periods	$ 52,571
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total estimated revenue expected to be recognized in future periods, expected timing	9 months
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	$ 62,373
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	$ 56,709
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	$ 49,491
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	$ 33,772
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	$ 16,488
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Total estimated revenue expected to be recognized in future periods, expected timing

OTHER FINANCIAL INFORMATION - Inventory (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Raw materials	$ 31,228	$ 25,429
Finished goods	65,208	48,971
Total inventory	$ 96,436	$ 74,400

OTHER FINANCIAL INFORMATION - Accrued Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Salaries, commissions, incentive compensation and benefits	$ 17,110	$ 13,062
Customer rebates and sales incentives	99,302	79,038
Freight	20,105	20,522
Operating lease liabilities, current	3,722	3,830
Liability due to supply agreements	10,161	14,653
Contingent consideration	0	3,710
Post combination expense accrual	7,764	8,602
Other	10,982	14,495
Total accrued liabilities	$ 169,146	$ 157,912

BUSINESS COMBINATIONS - Narrative (Details) - SolarLeadFactory $ in Millions	Mar. 14, 2022 USD ($)
Business Acquisition [Line Items]
Voting interests acquired	100.00%
Purchase price	$ 26.1
Contingency payable, maximum	10.0
Acquisition costs	$ 0.4

BUSINESS COMBINATIONS - Summary of Fair Values of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Mar. 14, 2022	Dec. 31, 2021	Dec. 31, 2020
Business Acquisition [Line Items]
Goodwill	$ 195,637		$ 181,254	$ 24,783
SolarLeadFactory
Business Acquisition [Line Items]
Cash and cash equivalents		$ 1,426
Net tangible assets acquired		813
Intangible assets		11,200
Goodwill		12,612
Net assets acquired		$ 26,051

BUSINESS COMBINATIONS - Summary of Identifiable Intangible Assets Acquired (Details) - SolarLeadFactory $ in Thousands	Mar. 14, 2022 USD ($)
Business Acquisition [Line Items]
Intangible assets	$ 11,200
Developed technology
Business Acquisition [Line Items]
Intangible assets	$ 3,600
Useful Life	5 years
Customer relationship
Business Acquisition [Line Items]
Intangible assets	$ 7,600
Useful Life	5 years

GOODWILL AND INTANGIBLE ASSETS - Schedule of Goodwill (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Goodwill [Roll Forward]
Beginning balance	$ 181,254	$ 24,783
Goodwill acquired	14,105	156,390
Currency translation adjustment	278	81
Ending balance	$ 195,637	$ 181,254

GOODWILL AND INTANGIBLE ASSETS - Schedule of Acquired Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Other indefinite-lived intangibles	$ 286	$ 286
Intangible assets with finite lives:
Additions	11,200	78,450
Accumulated Amortization	(26,284)	(20,499)
Net	102,887
Total purchased intangible assets, Gross	118,257	39,807
Total purchased intangible assets, Net	103,173	97,758
Developed technology
Intangible assets with finite lives:
Gross	38,650	13,100
Additions	3,600	25,550
Accumulated Amortization	(10,823)	(8,958)
Net	31,427	29,692
Customer relationship
Intangible assets with finite lives:
Gross	41,021	26,421
Additions	7,600	14,600
Accumulated Amortization	(13,206)	(11,448)
Net	35,415	29,573
Trade names
Intangible assets with finite lives:
Gross	37,700	0
Additions	0	37,700
Accumulated Amortization	(1,978)	(93)
Net	35,722	37,607
Order backlog
Intangible assets with finite lives:
Gross	600	0
Additions	0	600
Accumulated Amortization	(277)	0
Net	$ 323	$ 600

GOODWILL AND INTANGIBLE ASSETS - Amortization Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 5,786	$ 1,791
Developed technology
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	1,866	799
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	1,758	930
Trade names
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	1,885	62
Order backlog
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 277	$ 0

GOODWILL AND INTANGIBLE ASSETS - Expected Future Amortization Expense (Details) $ in Thousands	Mar. 31, 2022 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
2022 (remaining nine months)	$ 18,212
2023	24,096
2024	21,299
2025	19,984
2026	16,425
Thereafter	2,871
Net	$ 102,887

CASH EQUIVALENTS AND MARKETABLE SECURITIES - Schedule of Investments (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 1,015,630	$ 969,740
Gross Unrealized Gains	1	0
Gross Unrealized Losses	(10,383)	(2,859)
Fair Value	1,005,248	966,881
Cash and Cash Equivalents
Debt Securities, Available-for-sale [Line Items]
Fair Value	193,627	69,546
Marketable Securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	811,621	897,335
Money market funds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	193,627	35,789
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	193,627	35,789
Money market funds \| Cash and Cash Equivalents
Debt Securities, Available-for-sale [Line Items]
Fair Value	193,627	35,789
Money market funds \| Marketable Securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	0	0
Certificate of deposit
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	6,000	16,001
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(1)	(2)
Fair Value	5,999	15,999
Certificate of deposit \| Cash and Cash Equivalents
Debt Securities, Available-for-sale [Line Items]
Fair Value	0	6,000
Certificate of deposit \| Marketable Securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	5,999	9,999
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	164,243	215,964
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(379)	(114)
Fair Value	163,864	215,850
Commercial paper \| Cash and Cash Equivalents
Debt Securities, Available-for-sale [Line Items]
Fair Value	0	26,997
Commercial paper \| Marketable Securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	163,864	188,853
Corporate notes and bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	164,858	199,244
Gross Unrealized Gains	1	0
Gross Unrealized Losses	(2,860)	(872)
Fair Value	161,999	198,372
Corporate notes and bonds \| Cash and Cash Equivalents
Debt Securities, Available-for-sale [Line Items]
Fair Value	0	760
Corporate notes and bonds \| Marketable Securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	161,999	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	486,902	487,743
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(7,143)	(1,870)
Fair Value	479,759	485,873
U.S. Government agencies \| Cash and Cash Equivalents
Debt Securities, Available-for-sale [Line Items]
Fair Value	0	0
U.S. Government agencies \| Marketable Securities
Debt Securities, Available-for-sale [Line Items]
Fair Value	$ 479,759	$ 485,873

CASH EQUIVALENTS AND MARKETABLE SECURITIES - Schedule of Contractual Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Cash and Cash Equivalents [Abstract]
Contractual maturities, Due within one year, Amortized Cost	$ 692,296
Contractual maturities, Due within one year, Fair Value	689,588
Contractual maturities, Due within one to three years, Amortized Cost	323,334
Contractual maturities, Due within one to three years, Fair Value	315,660
Amortized Cost	1,015,630	$ 969,740
Fair Value	$ 1,005,248	$ 966,881

WARRANTY OBLIGATIONS - Summary of Warranty Activities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Changes in the Company's product warranty liability
Warranty obligations, beginning of period	$ 73,377	$ 45,913
Accruals for warranties issued during period	8,910	3,894
Changes in estimates	4,912	7,655
Settlements	(5,881)	(2,930)
Increase due to accretion expense	1,515	943
Other	746	(922)
Warranty obligations, end of period	83,579	54,553
Less: current portion	(23,960)	(14,303)	$ (19,395)
Non-current	$ 59,619	$ 40,250	$ 53,982

WARRANTY OBLIGATIONS - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Product Warranty Liability [Line Items]
Additional warranty expense	$ 4,912	$ 7,655
Expedited Freight Costs And Replacement Costs For IQ Batteries
Product Warranty Liability [Line Items]
Additional warranty expense	$ 4,900
Field Performance Data And Diagnostic Root-Cause Failure Analysis
Product Warranty Liability [Line Items]
Additional warranty expense		6,300
Increased Tariffs And Labor Reimbursement Costs
Product Warranty Liability [Line Items]
Additional warranty expense		$ 1,300

FAIR VALUE MEASUREMENTS - Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Assets [Abstract]
Marketable securities:	$ 1,005,248	$ 966,881
Liabilities:
Contingent consideration	0	3,710
Certificate of deposit
Assets [Abstract]
Marketable securities:	5,999	15,999
Commercial paper
Assets [Abstract]
Marketable securities:	163,864	215,850
Corporate notes and bonds
Assets [Abstract]
Marketable securities:	161,999	198,372
U.S. Government agencies
Assets [Abstract]
Marketable securities:	479,759	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	193,627	35,789
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	193,627	35,789
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	811,621	931,092
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:	5,999	9,999
Recurring \| Level 2 \| Commercial paper
Assets [Abstract]
Marketable securities:	163,864	188,853
Recurring \| Level 2 \| Corporate notes and bonds
Assets [Abstract]
Marketable securities:	161,999	197,612
Recurring \| Level 2 \| U.S. Government agencies
Assets [Abstract]
Marketable securities:	479,759	485,873
Recurring \| Level 2 \| U.S. Treasuries
Assets [Abstract]
Marketable securities:	0	14,998
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	0	6,000
Recurring \| Level 2 \| Commercial paper
Assets [Abstract]
Cash and cash equivalents	0	26,997
Recurring \| Level 2 \| Corporate notes and bonds
Assets [Abstract]
Cash and cash equivalents	0	760
Recurring \| Level 3
Assets [Abstract]
Investments in debt securities	39,926	41,042
Total assets measured at fair value	39,926	41,042
Liabilities:
Contingent consideration	0	3,710
Warranty obligations
Current	19,412	14,612
Non-current	42,174	36,395
Total warranty obligations measured at fair value	61,586	51,007
Total liabilities measured at fair value	61,586	54,717
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
	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jan. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Decrease in liability as a result of decreasing the profit element and risk premium input by 100 basis points	$ 500
Increase in liability as a result of decreasing the discount rate by 100 basis points	2,800
Decrease in liability as a result of increasing the discount rate by 100 basis points	3,100
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			$ 13,000
Level 2 \| Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in debt securities	0	$ 0
Level 2 \| Recurring \| Convertible Notes \| Notes due 2028
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes payable fair value	534,000
Level 2 \| Recurring \| Convertible Notes \| Notes due 2026
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes payable fair value	592,700
Level 2 \| Recurring \| Convertible Notes \| Notes due 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notes payable fair value	$ 245,900

FAIR VALUE MEASUREMENTS - Debt Securities Schedule of Fair Value (Details) - Investments in debt securities - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	$ 41,042	$ 0
Investment	0	25,000
Fair value adjustments included in other (expense) income, net	(1,116)	1,437
Balance at end of period	$ 39,926	$ 26,437

FAIR VALUE MEASUREMENTS - Contingent Consideration Schedule of Fair Value (Details) - Contingent consideration - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	$ 3,710	$ 0
Addition	0	3,500
Fair value adjustments included in other income (expense), net	15	40
Paid	(3,725)	0
Balance at end of period	$ 0	$ 3,540

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	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	$ 51,007	$ 28,736
Accruals for warranties issued during period	8,770	3,894
Changes in estimates	3,899	2,583
Settlements	(4,056)	(1,915)
Increase due to accretion expense	1,515	943
Other	451	(922)
Balance at end of period	$ 61,586	$ 33,319

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 products sold since January 1, 2014	Mar. 31, 2022	Dec. 31, 2021
Profit element and risk premium
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warranty obligations, measurement input	16.00%	15.00%
Credit-adjusted risk-free rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Warranty obligations, measurement input	12.00%	12.00%

DEBT - Long-term debt (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	Mar. 01, 2021
Debt Instrument [Line Items]
Total carrying amount of debt	$ 1,284,169	$ 1,037,646
Less: current portion of convertible notes	(87,219)	(86,052)
Debt, non-current	1,196,950	951,594
Convertible Notes \| Notes due 2028
Debt Instrument [Line Items]
Long-term debt, gross	575,000	575,000
Less: unamortized debt discount	0	(143,636)
Less: unamortized debt issuance costs	(7,684)	(5,775)	$ (6,600)
Total carrying amount of debt	567,316	425,589
Convertible Notes \| Notes due 2026
Debt Instrument [Line Items]
Long-term debt, gross	632,500	632,500
Less: unamortized debt discount	0	(104,755)
Less: unamortized debt issuance costs	(7,813)	(6,678)
Total carrying amount of debt	624,687	521,067
Convertible Notes \| Notes due 2025
Debt Instrument [Line Items]
Long-term debt, gross	102,175	102,175
Less: unamortized debt discount	(13,535)	(14,584)
Less: unamortized debt issuance costs	(1,421)	(1,539)
Total carrying amount of debt	87,219	86,052
Less: current portion of convertible notes	(102,200)
Convertible Notes \| Notes due 2023
Debt Instrument [Line Items]
Long-term debt, gross	5,000	5,000
Less: unamortized debt issuance costs	(53)	(62)
Total carrying amount of debt	$ 4,947	$ 4,938

DEBT - Convertible Senior Notes due in 2028 Narrative (Details) $ / shares in Units, $ in Thousands, shares in Millions		3 Months Ended
	Mar. 01, 2021 USD ($) trading_day $ / shares shares	Mar. 31, 2022 USD ($)	Mar. 31, 2021 USD ($)	Jan. 01, 2022 USD ($)	Dec. 31, 2021 USD ($)
Debt Instrument [Line Items]
Deferred taxes		$ 180,291			$ 122,470
Additional paid in capital		(666,511)			(837,924)
Retained Earnings (Accumulated Deficit)		328,206			405,737
Payment for bonds hedge		0	$ 286,235
Proceeds from sale of warrants		0	$ 220,800
Cumulative Effect, Period of Adoption, Adjustment \| Accounting Standards Update 2020-06
Debt Instrument [Line Items]
Additional paid in capital				$ 207,900
Convertible debt				244,500
Deferred income tax liabilities				62,300
Retained Earnings (Accumulated Deficit)				25,700
Notes due 2028 \| Cumulative Effect, Period of Adoption, Adjustment \| Accounting Standards Update 2020-06
Debt Instrument [Line Items]
Additional paid in capital				117,300
Convertible debt				141,300
Deferred income tax liabilities				36,000
Retained Earnings (Accumulated Deficit)				$ 12,000
Convertible Notes \| Notes due 2028
Debt Instrument [Line Items]
Debt instrument face amount	$ 575,000
Interest rate	0.00%
Proceeds from convertible debt	$ 566,400
Conversion ratio	0.0035104
Debt conversion price (in USD per share) \| $ / shares	$ 284.87
Convertible note, liability component	$ 415,000
Convertible note, equity component	160,000
Deferred taxes	40,100
Debt issuance costs	9,100
Unamortized debt issuance costs	6,600	$ 7,684			$ 5,775
Debt issuance costs, allocated to capital	$ 2,500
Conversion shares (in shares) \| shares	2.0
Payment for bonds hedge	$ 161,600
Warrants issued, strike price (in USD per share) \| $ / shares	$ 397.91
Proceeds from sale of warrants	$ 123,400
Convertible Notes \| Notes due 2028 \| Discount rate
Debt Instrument [Line Items]
Measurement input	0.0477
Period One \| Convertible Notes \| 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 \| 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 - Notes due 2028 - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Debt Instrument [Line Items]
Amortization of debt discount	$ 0	$ 1,611
Amortization of debt issuance costs	316	79
Total interest cost recognized	$ 316	$ 1,690

DEBT - Convertible Senior Notes due in 2026 Narrative (Details) $ / shares in Units, shares in Millions		3 Months Ended
	Mar. 01, 2021 USD ($) trading_day $ / shares shares	Mar. 31, 2022 USD ($)	Mar. 31, 2021 USD ($)	Jan. 01, 2022 USD ($)	Dec. 31, 2021 USD ($)	Mar. 12, 2021 USD ($)
Debt Instrument [Line Items]
Deferred taxes		$ 180,291,000			$ 122,470,000
Additional paid in capital		(666,511,000)			(837,924,000)
Retained Earnings (Accumulated Deficit)		328,206,000			405,737,000
Payment for bonds hedge		0	$ 286,235,000
Proceeds from sale of warrants		0	$ 220,800,000
Cumulative Effect, Period of Adoption, Adjustment \| Accounting Standards Update 2020-06
Debt Instrument [Line Items]
Additional paid in capital				$ 207,900,000
Convertible debt				244,500,000
Deferred income tax liabilities				62,300,000
Retained Earnings (Accumulated Deficit)				25,700,000
Notes due 2026 \| Cumulative Effect, Period of Adoption, Adjustment \| Accounting Standards Update 2020-06
Debt Instrument [Line Items]
Additional paid in capital				90,600,000
Convertible debt				103,200,000
Deferred income tax liabilities				26,300,000
Retained Earnings (Accumulated Deficit)				$ 13,700,000
Convertible Notes \| 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		$ 7,813,000			$ 6,678,000
Debt issuance costs, allocated to capital	$ 2,000,000
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 \| Notes due 2026 \| Discount rate
Debt Instrument [Line Items]
Measurement input	0.0444
Period One \| Convertible Notes \| 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 \| 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 - Notes due 2026 - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Debt Instrument [Line Items]
Amortization of debt discount	$ 0	$ 1,786
Amortization of debt issuance costs	485	135
Total interest cost recognized	$ 485	$ 1,921

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	Mar. 31, 2022 USD ($) $ / shares shares	Jun. 30, 2021 USD ($) shares	Mar. 31, 2021 USD ($) shares	Dec. 31, 2021 USD ($) $ / shares shares	May 20, 2020 USD ($) $ / shares shares
Debt Instrument [Line Items]
Principal amount outstanding				$ 1,284,169,000			$ 1,037,646,000
Common stock, par value (in usd per share) \| $ / shares				$ 0.00001			$ 0.00001	$ 0.00001
Common stock, shares authorized (in shares) \| shares			150,000,000	300,000,000			300,000,000	200,000,000
Deferred taxes				$ 180,291,000			$ 122,470,000
Partial repurchase of convertible notes				0		$ 289,233,000
Loss on partial settlement of convertible notes				0		56,369,000
Debt, current				87,219,000			86,052,000
Payment for bonds hedge				0		286,235,000
Proceeds from sale of warrants				$ 0		220,800,000
Warrants obligations measured at fair value								$ 96,400,000
Convertible Notes
Debt Instrument [Line Items]
Convertible notes embedded derivative								117,100,000
Convertible Notes \| Notes due 2025
Debt Instrument [Line Items]
Debt instrument face amount		$ 320,000,000
Interest rate		0.25%		1.00%
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				$ 87,219,000			86,052,000
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				$ 13,535,000			$ 14,584,000
Remaining discount amortization period				290.00%
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 \| Notes due 2025 \| Discount rate
Debt Instrument [Line Items]
Measurement input	0.0435
Period One \| Convertible Notes \| 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 \| 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 - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Notes due 2025
Debt Instrument [Line Items]
Contractual interest expense	$ 64	$ 150
Amortization of debt discount	1,049	2,389
Amortization of debt issuance costs	118	294
Total interest cost recognized	1,231	2,833
Notes due 2028
Debt Instrument [Line Items]
Amortization of debt discount	0	1,611
Amortization of debt issuance costs	316	79
Total interest cost recognized	316	1,690
Notes due 2026
Debt Instrument [Line Items]
Amortization of debt discount	0	1,786
Amortization of debt issuance costs	485	135
Total interest cost recognized	$ 485	$ 1,921

DEBT - Convertible Senior Notes due 2023 Narrative (Details) - Convertible Notes - Notes due 2023		1 Months Ended
	Jun. 05, 2019 USD ($) shares	Aug. 31, 2018 USD ($) $ / shares	Mar. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
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 - Notes due 2023 - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Debt Instrument [Line Items]
Contractual interest expense	$ 50	$ 50
Amortization of debt issuance costs	10	10
Total interest cost recognized	$ 60	$ 60

COMMITMENTS AND CONTINGENCIES - Narrative (Details) $ in Millions	Mar. 31, 2022 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Term of lease contract, maximum renewal term	12 years
Purchase obligation	$ 398.6

COMMITMENTS AND CONTINGENCIES - Lease Expense Components (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Operating lease costs	$ 1,937	$ 1,631

COMMITMENTS AND CONTINGENCIES - Lease Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Operating lease liabilities, current (Accrued liabilities)	$ 3,722	$ 3,830
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Total accrued liabilities	Total accrued liabilities
Operating lease liabilities, non-current (Other liabilities)	$ 17,591	$ 11,920
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Noncurrent	Other Liabilities, Noncurrent
Total operating lease liabilities	$ 21,313	$ 15,750
Weighted average remaining lease term	5 years 10 months 24 days	5 years 10 months 24 days
Weighted average discount rate	6.40%	7.40%

COMMITMENTS AND CONTINGENCIES - Supplemental Cash Flow and Other Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Operating cash flows from operating leases	$ 1,518	$ 1,361
Lease liabilities arising from obtaining right-of-use assets	$ 6,742	$ 0

COMMITMENTS AND CONTINGENCIES - Schedule of Minimum Lease Payments Under Noncancelable Operating Leases (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2022 (remaining nine months)	$ 3,815
2023	5,262
2024	4,362
2025	3,632
2026	2,637
Thereafter	5,845
Total lease payments	25,553
Less: imputed lease interest	(4,240)
Total lease liabilities	$ 21,313	$ 15,750

STOCK-BASED COMPENSATION - Summary of Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 47,797	$ 14,844
Cost of revenues
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	2,507	982
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	13,729	5,749
Sales and marketing
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	13,057	3,537
General and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 18,504	$ 4,576

STOCK-BASED COMPENSATION - Summary of Stock-Based Compensation Expense Associated with Each Type of Award (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 47,797	$ 14,844
Stock options, RSUs and PSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	44,112	13,840
Employee stock purchase plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	1,382	1,004
Post combination expense accrual (Accrued liabilities)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 2,303	$ 0

STOCK-BASED COMPENSATION - Narrative (Details) $ in Millions	3 Months Ended
	Mar. 31, 2022 USD ($)
Share-based Payment Arrangement [Abstract]
Total unrecognized compensation cost	$ 231.2
Weighted-average recognition period for unrecognized compensation cost	2 years 10 months 24 days

STOCK-BASED COMPENSATION - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Number of Shares Outstanding
Outstanding, beginning balance (in shares)	2,264
Granted (in shares)	0
Exercised (in shares)	(194)
Canceled (in shares)	0
Outstanding, ending balance (in shares)	2,070
Shares outstanding, vested and expected to vest (in shares)	2,070
Shares outstanding, exercisable (in shares)	2,070
Weighted- Average Exercise Price per Share
Outstanding, beginning balance (in usd per share)	$ 1.90
Granted (in usd per share)	0
Exercised (in usd per share)	2.09
Canceled (in usd per share)	0
Outstanding, ending balance (in usd per share)	1.89
Weighted-average exercise price, vested and expected (in usd per share)	1.89
Weighted-average exercise price, exercisable (in usd per share)	$ 1.89
Weighted-Average Remaining Contractual Term
Outstanding	2 years 7 months 6 days
Vested and expected to vest	2 years 7 months 6 days
Exercisable	2 years 7 months 6 days
Aggregate Intrinsic Value
Outstanding	$ 413,757
Exercised	42,091
Vested and expected to vest	413,757
Exercisable	$ 413,757
Share price (in usd per share)	$ 201.78

STOCK-BASED COMPENSATION - Summary of Stock Options Outstanding (Details) shares in Thousands	3 Months Ended
	Mar. 31, 2022 $ / shares shares
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Options outstanding, number of shares (shares) \| shares	2,070
Options outstanding - weighted- average remaining life	2 years 7 months 6 days
Options outstanding - weighted- average exercise price (usd per share)	$ 1.89
Options exercisable - number of shares exercisable (shares) \| shares	2,070
Options exercisable - weighted-average exercise price (usd per share)	$ 1.89
$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 1 month 6 days
Options outstanding - weighted- average exercise price (usd per share)	$ 0.85
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 6 months
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)	$ 1.29
$1.31 —– $1.90
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)	$ 1.90
Options outstanding, number of shares (shares) \| shares	422
Options outstanding - weighted- average remaining life	2 years
Options outstanding - weighted- average exercise price (usd per share)	$ 1.33
Options exercisable - number of shares exercisable (shares) \| shares	422
Options exercisable - weighted-average exercise price (usd per share)	$ 1.33
$1.92 —– $14.58
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Exercise price range, lower limit (usd per share)	1.92
Exercise price range, upper limit (usd per share)	$ 14.58
Options outstanding, number of shares (shares) \| shares	151
Options outstanding - weighted- average remaining life	3 years 1 month 6 days
Options outstanding - weighted- average exercise price (usd per share)	$ 6.30
Options exercisable - number of shares exercisable (shares) \| shares	151
Options exercisable - weighted-average exercise price (usd per share)	$ 6.30
$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 1 month 6 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 and Performance Stock Units (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Aggregate Intrinsic Value
Share price (in usd per share)	$ 201.78
Restricted stock units
Number of Shares Outstanding
Outstanding, beginning balance (in shares)	2,786
Granted (in shares)	153
Vested (in shares)	(639)
Canceled (in shares)	(43)
Outstanding, ending balance (in shares)	2,257
Number of shares outstanding, expected to vest (in shares)	2,257
Weighted Average Fair Value per Share at Grant Date
Outstanding, beginning balance (in usd per share)	$ 100.73
Granted (in usd per share)	150.81
Vested (in usd per share)	70.19
Canceled (in usd per share)	120.94
Outstanding, ending balance (in usd per share)	112.40
Weighted-Average Fair Value per Share at Grant Date, Expected to vest (in usd per share)	$ 112.40
Weighted-Average Remaining Contractual Term
Outstanding	1 year 3 months 18 days
Expected to vest	1 year 3 months 18 days
Aggregate Intrinsic Value
Outstanding	$ 455,509
Vested	102,631
Aggregate intrinsic value, expected to vest	$ 455,509
Performance shares
Number of Shares Outstanding
Outstanding, beginning balance (in shares)	445
Granted (in shares)	27
Vested (in shares)	(303)
Canceled (in shares)	(169)
Outstanding, ending balance (in shares)	0
Weighted Average Fair Value per Share at Grant Date
Outstanding, beginning balance (in usd per share)	$ 169.82
Granted (in usd per share)	160.09
Vested (in usd per share)	168.88
Canceled (in usd per share)	169.93
Outstanding, ending balance (in usd per share)	$ 0
Weighted-Average Remaining Contractual Term
Outstanding	0 years
Aggregate Intrinsic Value
Outstanding	$ 0
Vested	$ 51,393

INCOME TAXES (Details) - USD ($) $ in Thousands	3 Months Ended
INCOME TAXES (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Mar. 31, 2021
Income Tax Disclosure [Abstract]
Income tax provision (benefit)	$ 5,586	$ (33,364)
Income (loss) before income taxes	$ 57,407	$ (1,666)

- 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

- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References + Details

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	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Numerator:
Net income	$ 51,821	$ 31,698
Interest and financing costs, net	1,559	44
Adjusted net income	$ 53,380	$ 31,742
Weighted average common shares outstanding (in shares)	134,327	131,303
Denominator:
Weighted average common shares outstanding (in shares)	134,327	131,303
Employee stock-based awards (in shares)	3,661	5,735
Weighted average common shares outstanding for diluted calculation (in shares)	144,617	146,442
Net income per share, basic (in USD per share)	$ 0.39	$ 0.24
Net income per share, diluted (in USD per share)	$ 0.37	$ 0.22
Notes due 2024
Denominator:
Warrants (in shares)	0	2,506
Notes due 2025
Denominator:
Warrants (in shares)	401	1,301
Convertible Notes \| Notes due 2023
Denominator:
Notes due (in shares)	900	900
Convertible Notes \| Notes due 2024
Denominator:
Notes due (in shares)	0	2,984
Convertible Notes \| Notes due 2025
Denominator:
Notes due (in shares)	1,253	1,713
Convertible Notes \| Notes due 2026
Denominator:
Notes due (in shares)	2,057	0
Convertible Notes \| Notes due 2028
Denominator:
Notes due (in shares)	2,018	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	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	6,604	3,445
Employee stock-based awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	359	54
Warrants \| Notes due 2028
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	3,093	1,070
Warrants \| Notes due 2026
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	3,152	1,070
Notes due \| Notes due 2028
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	0	569
Notes due \| Notes due 2026
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	0	682

NET INCOME PER SHARE - Narrative (Details)	Mar. 31, 2022	Mar. 09, 2020
Notes due 2025 \| Convertible Notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Interest rate	1.00%	0.25%

RELATED PARTY - Narrative (Details) - Convertible Notes - Notes due 2023 - USD ($)	Mar. 31, 2022	Dec. 31, 2021	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