Acacia Communications (ACIA) 10-K 1 Mar 21 2020 FY Annual report Financial data

Cover Page

Cover Page - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Feb. 19, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-37771
Entity Registrant Name	Acacia Communications, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	27-0291921
Entity Address, Address Line One	Three Mill and Main Place
Entity Address, Address Line Two	Suite 400
Entity Address, City or Town	Maynard
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	01754
City Area Code	978
Local Phone Number	938-4896
Title of 12(b) Security	Common Stock, $0.0001 par value per share
Trading Symbol	ACIA
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
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
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 2,597.8
Entity Common Stock, Shares Outstanding		42,631,607
Documents Incorporated by Reference	None.
Entity Central Index Key	0001651235
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Amendment Flag	false

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 121,685	$ 36,617
Marketable securities - short-term	298,185	300,129
Accounts receivable	118,414	97,948
Inventory	37,981	40,820
Prepaid expenses and other current assets	8,023	6,518
Total current assets	584,288	482,032
Marketable securities - long term	170,891	134,632
Property and equipment, net	27,914	26,801
Operating lease right-of-use assets	28,483	25,046
Deferred tax asset	49,082	51,798
Other assets	1,106	1,106
Total assets	861,764	721,415
Current liabilities:
Accounts payable	61,489	46,957
Accrued liabilities	62,228	61,680
Deferred revenue	5,754	4,483
Total current liabilities	129,471	113,120
Income taxes payable	6,280	7,117
Non-current operating lease liabilities	18,099	15,726
Other long-term liabilities	4,098	7,029
Total liabilities	157,948	142,992
Commitments and contingencies (Note 13)
Stockholders’ equity:
Preferred stock, $0.0001 par value; 5,000 shares authorized; none issued and outstanding at December 31, 2020 and 2019	0	0
Common stock, $0.0001 par value; 150,000 shares authorized; 43,296 and 42,399 shares issued at December 31, 2020 and 2019, respectively	4	4
Treasury stock, at cost; 974 shares at December 31, 2020 and 2019, respectively	(39,712)	(39,712)
Additional paid-in capital	437,285	402,032
Accumulated other comprehensive income	469	720
Retained earnings	305,770	215,379
Total stockholders’ equity	703,816	578,423
Total liabilities and stockholders’ equity	$ 861,764	$ 721,415

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Preferred stock, par value (in USD per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in USD per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	150,000,000	150,000,000
Common stock, shares issued (in shares)	43,296,000	42,399,000
Treasury stock, shares (in shares)	974,000	974,000

CONSOLIDATED INCOME STATEMENTS

CONSOLIDATED INCOME STATEMENTS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Revenue	$ 583,451	$ 464,663	$ 339,891
Cost of revenue	299,351	243,981	192,771
Gross profit	284,100	220,682	147,120
Operating expenses:
Research and development	134,398	128,700	102,406
Sales, general and administrative	60,386	80,581	51,864
Total operating expenses	194,784	209,281	154,270
Income (loss) from operations	89,316	11,401	(7,150)
Other income, net:
Interest income, net	5,598	10,413	7,209
Other expense, net	(71)	(173)	(463)
Total other income, net	5,527	10,240	6,746
Income (loss) before provision (benefit) for income taxes	94,843	21,641	(404)
Income tax expense (benefit)	4,452	(11,198)	(5,320)
Net income	$ 90,391	$ 32,839	$ 4,916
Earnings per share:
Basic (in USD per share)	$ 2.16	$ 0.80	$ 0.12
Diluted (in USD per share)	$ 2.09	$ 0.77	$ 0.12
Weighted-average shares used to compute earnings per share:
Basic (in shares)	41,938	40,883	40,259
Diluted (in shares)	43,233	42,554	41,997

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 90,391	$ 32,839	$ 4,916
Other comprehensive (loss) income:
Changes in unrealized gain (loss) on marketable securities, net of income taxes of $(47), $(89) and $(18) for the years ended December 31, 2020, 2019 and 2018, respectively	(251)	1,092	(7)
Comprehensive income	$ 90,140	$ 33,931	$ 4,909

CONSOLIDATED STATEMENTS OF CO_2

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Changes in unrealized loss on marketable securities, tax	$ (47)	$ (89)	$ (18)

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Effect of adopted accounting standards	Common Stock	Treasury Stock	Additional Paid-in Capital	Accumulated Other Comprehensive (Loss) Income	Accumulated Other Comprehensive (Loss) IncomeEffect of adopted accounting standards	Retained Earnings	Retained EarningsEffect of adopted accounting standards
Beginning balance (in shares) at Dec. 31, 2017			39,606	0
Beginning balance at Dec. 31, 2017	$ 502,050	$ 157	$ 4	$ 0	$ 324,944	$ (320)	$ (45)	$ 177,422	$ 202
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury stock acquired (in shares)				974
Treasury stock acquired	(39,712)			$ (39,712)
Vesting of restricted common stock (in shares)			21
Exercise of common stock options (in shares)			489
Exercise of common stock options	2,512				2,512
Vesting of restricted stock units (in shares)			782
Common stock issued under employee stock purchase plan (in shares)			126
Common stock issued under employee stock purchase plan	3,301				3,301
Stock-based compensation expense	29,510				29,510
Unrealized losses on marketable securities, net of tax	(7)					(7)
Net income	4,916							4,916
Ending balance (in shares) at Dec. 31, 2018			41,024	974
Ending balance at Dec. 31, 2018	502,727		$ 4	$ (39,712)	360,267	(372)		182,540
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of common stock options (in shares)			382
Exercise of common stock options	2,658				2,658
Vesting of restricted stock units (in shares)			890
Common stock issued under employee stock purchase plan (in shares)			103
Common stock issued under employee stock purchase plan	4,275				4,275
Stock-based compensation expense	34,832				34,832
Unrealized losses on marketable securities, net of tax	1,092					1,092
Net income	32,839							32,839
Ending balance (in shares) at Dec. 31, 2019			42,399	974
Ending balance at Dec. 31, 2019	$ 578,423		$ 4	$ (39,712)	402,032	720		215,379
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of common stock options (in shares)	161		161
Exercise of common stock options	$ 2,176				2,176
Vesting of restricted stock units (in shares)			736
Stock-based compensation expense	33,077				33,077
Unrealized losses on marketable securities, net of tax	(251)					(251)
Net income	90,391							90,391
Ending balance (in shares) at Dec. 31, 2020			43,296	974
Ending balance at Dec. 31, 2020	$ 703,816		$ 4	$ (39,712)	$ 437,285	$ 469		$ 305,770

CONSOLIDATED STATEMENTS OF ST_2

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Stockholders' Equity [Abstract]
Changes in unrealized loss on marketable securities, tax	$ (47)	$ (89)	$ (18)

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 90,391	$ 32,839	$ 4,916
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	11,070	12,559	13,646
Stock-based compensation	33,663	35,153	29,593
Deferred income taxes	2,716	(13,081)	3,133
Non-cash lease expense	4,569	4,872	0
Other non-cash charges (benefits)	789	(2,244)	(799)
Changes in operating assets and liabilities:
Accounts receivable	(20,466)	(7,117)	(4,229)
Inventory	2,839	(15,309)	36,721
Prepaid expenses and other current assets	(1,505)	6,080	6,219
Other assets	9	(302)	1,113
Accounts payable	15,270	(835)	1,377
Accrued liabilities	(189)	26,750	(5,467)
Deferred revenue	(2,173)	(881)	8,357
Income taxes payable	(837)	(1,674)	(12,243)
Lease liabilities	(5,222)	(4,541)	0
Other long-term liabilities	128	550	748
Net cash provided by operating activities	131,052	72,819	83,085
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property and equipment	(12,879)	(11,837)	(14,660)
Purchases of marketable securities	(418,939)	(476,207)	(382,438)
Sales and maturities of marketable securities	383,667	384,467	340,920
Deposits	(9)	(2)	(59)
Net cash used in investing activities	(48,160)	(103,579)	(56,237)
CASH FLOWS FROM FINANCING ACTIVITIES:
Treasury stock acquired	0	0	(39,712)
Proceeds from the issuance of common stock under stock-based compensation plans	2,176	6,933	5,813
Net cash provided by (used in) financing activities	2,176	6,933	(33,899)
Net increase (decrease) in cash and cash equivalents	85,068	(23,827)	(7,051)
Cash and cash equivalents—Beginning of period	36,617	60,444	67,495
Cash and cash equivalents—End of period	121,685	36,617	60,444
Supplemental cash flow disclosures:
Cash paid (refunds received) for income taxes, net	3,142	(129)	(5,053)
Supplemental disclosure of non-cash investing and financing activities:
Right-of-use assets acquired under operating leases	4,913	7,084	0
Capital expenditures incurred but not yet paid	$ 600	$ 1,338	$ 196

NATURE OF THE BUSINESS AND OPER

NATURE OF THE BUSINESS AND OPERATIONS	12 Months Ended
	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
NATURE OF THE BUSINESS AND OPERATIONS	NATURE OF THE BUSINESS AND OPERATIONS Acacia Communications, Inc. was incorporated on June 2, 2009, as a Delaware corporation. Acacia Communications, Inc. and its wholly owned subsidiaries (the “Subsidiaries”) are collectively referred to as the Company. The Company’s mission is to deliver high-speed coherent optical interconnect products that transform communications networks relied upon by cloud infrastructure operators and content and communication service providers, through improvements in performance and capacity and reductions in associated costs. By implementing optical interconnect technology in a silicon-based platform, a process the Company refers to as the siliconization of optical interconnect, the Company believes it is leading a disruption that is analogous to the computing industry’s integration of multiple functions into a microprocessor. The Company's products fall into three product groups: embedded modules, pluggable modules and semiconductors. The Company's embedded module and pluggable module product groups consist of optical interconnect modules with transmission speeds ranging from 100 to 1,200 gigabits per second (“Gbps”) for use in long-haul, metro and inter-data center markets. The Company's semiconductor product group consists of its low-power coherent digital signal processor application-specific integrated circuits (“DSP ASICs”) and its silicon photonic integrated circuits (“silicon PICs”) which are either integrated into the Company's embedded and pluggable modules or sold to customers on a standalone basis for integration into internally developed or other merchant modules. The Company’s modules perform a majority of the digital signal processing and optical functions in optical interconnects and offer low power consumption, high density and high speeds at attractive price points. Through the use of standard interfaces, the Company’s modules can be easily integrated with customers’ network equipment. The advanced software in the Company’s modules enables increased configurability and automation, provides insight into network and connection point characteristics and helps identify network performance problems, all of which increase flexibility and reduce operating costs. The Company is headquartered in Maynard, Massachusetts, and has wholly owned subsidiaries in North America, Europe and Asia. Merger with Cisco Systems On July 8, 2019, the Company, Cisco Systems, Inc., a California corporation (“Parent”), and Amarone Acquisition Corp., a Delaware corporation and a wholly owned subsidiary of Parent (“Merger Sub”), entered into an Agreement and Plan of Merger (the “Original Merger Agreement”). On January 14, 2021, the Company, Parent and Merger Sub entered into an Amended and Restated Agreement and Plan of Merger (the “Amended and Restated Merger Agreement”), which amended and restated the Original Merger Agreement in its entirety. The Amended and Restated Merger Agreement provided, subject to its terms and conditions, for the Company’s acquisition by Parent at a price of $115.00 per share of the Company’s common stock, $0.0001 par value per share (each a “Share”), in cash, without interest and subject to deduction for any required withholding tax (the “Merger Consideration”), through the merger of Merger Sub with and into the Company (the “Merger”), with the Company surviving the Merger as a wholly owned subsidiary of Parent. The Company’s Board of Directors unanimously approved the Merger and the Amended and Restated Merger Agreement and recommended that stockholders adopt the Amended and Restated Merger Agreement, and the Company’s stockholders adopted the Amended and Restated Merger Agreement at a special meeting held on March 1, 2021. The Merger was completed on March 1, 2021 following such special meeting. As of the effective time of the Merger, the Company became a wholly owned subsidiary of Parent and is no longer a publicly held corporation, its common stock will be delisted from The Nasdaq Global Select Market and deregistered under the Securities Exchange Act of 1934, as amended (the “Exchange Act”) and it will no longer be required to file periodic reports with the SEC. During the years ended December 31, 2020 and 2019, the Company recorded acquisition-related costs of $2.4 million and $7.6 million, respectively, in sales, general and administrative expenses within our consolidated income statements. Impact of COVID-19 An outbreak of the novel coronavirus, severe acute respiratory syndrome coronavirus 2 (“SARS-CoV-2”), and the coronavirus disease, COVID-19, was identified in China in late 2019 and has spread globally. The Centers for Disease Control and Prevention has recognized this outbreak as a pandemic which has resulted in authorities imposing, and businesses and individuals implementing, numerous unprecedented measures to try to contain the virus, such as travel bans and restrictions, quarantines, shelter-in-place/stay-at-home and social distancing orders and shutdowns. These measures have impacted and may further impact the Company’s workforce and operations, the operations of the Company’s customers, and those of the

BASIS OF PRESENTATION

BASIS OF PRESENTATION	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
BASIS OF PRESENTATION	BASIS OF PRESENTATION Principles of Consolidation The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and include the accounts of Acacia Communications, Inc., and its Subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenue and expenses during the reporting period. Actual results could differ from those estimates. Comprehensive Income Comprehensive income consists of two components, net income and other comprehensive income (loss). Other comprehensive income (loss) refers to income or losses that are recorded as an element of stockholders’ equity but are excluded from net income. The Company’s other comprehensive income (loss) consists of net unrealized gains and losses on available-for-sale securities, net of the related tax effect.

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Revenue Recognition and Deferred Revenue The Company generates all of its revenue from contracts with customers. The Company considers customer purchase orders, which in many cases are governed by master purchasing agreements, to be contracts with customers. The Company’s contracts with customers are generally for product only, and do not include other performance obligations such as services, extended warranties or other material rights. As part of its assessment of each contract, the Company evaluates certain factors including the customer’s ability to pay (or credit risk). For each contract, the Company considers the promise to transfer products, each of which is distinct, to be the identified performance obligations. In determining the transaction price, the price stated on the purchase order is typically fixed and represents the net consideration to which the Company expects to be entitled, and therefore there is no variable consideration. As the Company’s standard payment terms are less than one year, the Company has elected, as a practical expedient, to not assess whether a contract has a significant financing component. The Company allocates the transaction price to each distinct product based on its relative standalone selling price. The product price as specified on the purchase order is considered the standalone selling price as it is an observable source that depicts the price as if sold to a similar customer in similar circumstances. Revenue is recognized when control of the product is transferred to the customer (i.e., when the Company’s performance obligation is satisfied), which typically occurs upon shipment from the Company’s manufacturing site or delivery to the customer’s named location. In determining whether control has transferred, the Company considers if there is a present right to payment from the customer and when physical possession, legal title and risks and rewards of ownership have transferred to the customer. The Company also considered certain customer contracts that include acceptance clauses, but has concluded that delivery to the customer’s named location is the point at which the customer is able to direct the use of, and obtain substantially all of the remaining benefits from, the asset, and therefore the acceptance is considered a formality that does not impact the timing of revenue recognition. The Company generally provides an assurance warranty that its products will substantially conform to the agreed-upon specifications for 12 to 24 months from the date of shipment. The Company’s liability is limited to the cost of repair or replacement of the defective part. The Company does not consider activities related to such warranties to be a separate performance obligation. The terms and conditions of sale generally do not allow for refunds or product returns other than for warranty repairs. The Company has a limited number of customer contracts that provide for the performance of services or include multiple performance obligations. Once the Company determines the performance obligations, the Company determines the transaction price, which includes estimating the amount of variable consideration to be included in the transaction price, if any. The Company then allocates the transaction price to each performance obligation in the contract based on a relative stand-alone selling price method or using the variable consideration allocation exception if the required criteria are met. The corresponding revenues are recognized as the related performance obligations are satisfied. A receivable is recognized in the period the Company ships the product. Payment terms on invoiced amounts are based on contractual terms with each customer. In some cases, if control of the product has not yet transferred to the customer or the timing of the payments made by the customer precedes the Company’s fulfillment of the performance obligation, the Company recognizes a contract liability that is classified as “deferred revenue.” Deferred product costs represent products that have been billed to customers, for which the revenue associated with the arrangement has been deferred as a result of not meeting the revenue recognition criteria. The Company defers the product costs until recognition of the related revenue occurs. The Company has concluded that none of the costs it has incurred to obtain and fulfill its ASC 606 contracts meet the capitalization criteria, and as such, there are no costs deferred and recognized as assets on the consolidated balance sheet as of December 31, 2020 and 2019. Cost of Revenue The Company records all costs associated with its product sales in cost of revenue. These costs include the cost of materials, contract manufacturing fees, assembly, test, quality assurance, logistics-related fees and impacts of manufacturing yield. Cost of revenue also includes indirect costs such as warranty, excess and obsolete inventory charges, general overhead costs and depreciation. Financial Instruments Cash equivalents include all highly liquid investments with an original maturity of three months or less upon acquisition. Cash equivalents may consist of bank deposit accounts, money market funds, U.S. treasury bonds, commercial paper, certificates of deposit, asset-backed securities and corporate debt securities. The Company’s marketable debt securities have been classified and accounted for as available-for-sale. Management determines the appropriate classification of its investments at the time of purchase and reevaluates the classifications at each balance sheet date. The Company classifies its investments in marketable debt securities as either short-term or long-term based on each instrument’s underlying contractual maturity date. The Company’s investments in marketable debt securities are carried at fair value, with unrealized gains and losses, net of taxes, reported as a component of accumulated other comprehensive income (loss) in stockholders’ equity, with the exception of unrealized losses believed to be other-than-temporary which are reported in earnings in the current period. Concentrations of Credit Risk Financial instruments that subject the Company to significant concentrations of credit risk consist primarily of cash and cash equivalents, marketable securities and accounts receivable. The majority of the Company’s cash and cash equivalents are at two financial institutions and the balances often exceed federally insured limits. Management believes that the financial institutions that hold the Company’s cash and cash equivalents are financially creditworthy and, accordingly, minimal credit risk exists with respect to those balances. Marketable securities consist of investments in U.S. treasury bonds, commercial paper, certificates of deposit, asset-backed securities and corporate debt securities. The main objective of the Company’s current investment policy is to preserve capital and maintain liquidity. The Company seeks to limit the amount of investments in any single issuer. As a result, the Company believes that, as of December 31, 2020 and 2019, its concentration of credit risk related to marketable securities was not significant. To minimize credit risk related to accounts receivable, ongoing credit evaluations of customers’ financial condition are performed and the Company maintains allowances for potential credit losses as needed. The Company has determined that an immaterial amount of allowance was needed as of December 31, 2020 and 2019, as the majority of accounts receivable balances were expected to be collected. Inventory Inventory, which consists of raw materials, work-in-process, and finished goods, is stated at the lower of cost or net realizable value, as determined on a specific cost basis and using the first-in, first-out convention. The Company reduces the carrying value of inventory to its estimated net realizable value for those items that are potentially excess, obsolete or slow moving based on changes in customer demand, technology developments or other economic factors. Such reductions in the carrying value of inventory are recorded within cost of revenue in the consolidated income statements. Any excess or obsolete inventory write-downs taken establish a new cost basis for the underlying inventory and cannot be reversed if there are subsequent increases in the Company’s demand forecast. If the Company is later able to sell such inventory, any related reserves would be reversed in the period of sale. Property and Equipment Property and equipment are recorded at cost and depreciated using the straight-line method over the estimated useful lives of the related assets. The costs of additions and improvements are capitalized, while maintenance and repairs are charged to expense as incurred. The estimated useful lives of the Company’s property and equipment are as follows: Engineering laboratory equipment 3-7 years Computer software 1-3 years Computer equipment 3 years Furniture and fixtures 3-7 years Leasehold improvements Lesser of lease term or life of asset When assets are retired or otherwise disposed of, the assets and related accumulated depreciation are derecognized from the accounts and the resulting gain or loss is reflected in the consolidated income statements. Leases The Company determines if an arrangement is a lease at inception. Operating leases are included in operating lease right-of-use (“ROU”) assets, accrued liabilities, and noncurrent operating lease liabilities in the Company’s consolidated balance sheets. ROU assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. Operating lease ROU assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. As most of the Company’s leases do not provide an implicit rate, the Company uses its incremental borrowing rate based on the estimated rate of interest for collateralized borrowing over a similar term of the lease payments at commencement date. The Company’s lease terms do not include options to extend or terminate leases unless the Company is reasonably certain that it will exercise those options. Lease expense for lease payments is recognized on a straight-line basis over the lease term. The Company has elected not to separate nonlease components from associated lease components for its real estate lease assets. Impairment of Long-Lived Assets Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the asset may not be recoverable. When such events occur, the Company compares the carrying amounts of the assets to their estimated undiscounted future cash flows. If this comparison indicates that there is an impairment, the amount of the impairment is calculated as the difference between the carrying value and the fair value. The Company recorded $0.3 million of impairments in the year ended December 31, 2019. No impairments were recognized for the years ended December 31, 2020 and 2018. Warranties The Company’s standard warranty obligation to its customers provides for repair or replacement of a defective product at the Company’s discretion for a period of time following purchase, generally between 12 and 24 months. Factors that affect the warranty obligation include product failure rates, material usage and service delivery costs incurred in correcting product failures. In addition, from time to time, specific warranty accruals may be made if unforeseen technical problems arise. The estimated cost associated with fulfilling the Company’s warranty obligation to customers is recorded in cost of revenue. Refer to Note 13 for additional information regarding warranty activity. Commitments and Contingencies In the normal course of business, the Company may become subject to loss contingencies, such as legal proceedings and claims arising out of its business. An accrual for a loss contingency is recognized when it is probable that an asset has been impaired or a liability has been incurred and the amount of the loss can be reasonably estimated. The Company expenses legal costs associated with loss contingencies as they are incurred. Advertising Costs The Company expenses advertising costs as incurred. During the years ended December 31, 2020 and 2019, the Company incurred $0.2 million of advertising expenses. In the year ended December 31, 2018, the Company did not incur any advertising expenses. Research and Development Costs The Company expenses all research and development costs as incurred. Research and development costs consist primarily of salary and benefit expenses, including stock-based compensation, for employees, costs for contractors engaged in research, design and development activities, costs incurred directly and with support from external vendors, such as outsourced development costs, as well as support costs for prototypes, depreciation, purchased intellectual property, facilities and travel. Stock-Based Compensation The Company accounts for share-based payment awards granted to employees at fair value, which is measured using the fair value of the Company’s common stock on the grant date for time-vested restricted stock units (“RSUs”). Other input assumptions are used to determine the valuation of performance- or market-based RSU awards, as well as in the Black-Scholes option-pricing model for stock option awards and employee stock purchase rights. The measurement date for the fair value of employee awards is the date of grant. For all time-vested awards, stock-based compensation costs are recognized as expense on a ratable basis over the requisite service period, which is generally the vesting period. For awards with market and/or performance conditions, the Company recognizes stock-based compensation expense using the accelerated attribution method. Foreign Currency Transactions The functional currency of the Company’s Subsidiaries is the U.S. dollar. All monetary assets and liabilities denominated in a foreign currency are revalued into U.S. dollars at the exchange rate on the consolidated balance sheet date. When transactions are required to be paid in the local currency of any Subsidiary, any resulting foreign currency transaction gain or loss is recorded as a component of other expense, net, in the consolidated income statements. To date, foreign currency transaction gain or loss associated with the Company’s Subsidiaries has not been significant. During the years ended December 31, 2020, 2019 and 2018, the Company recorded foreign currency transaction losses of $0.2 million, $0.2 million and $0.4 million, respectively. Income Taxes The Company recognizes deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the Company’s consolidated financial statements and tax returns. Deferred tax assets and liabilities are determined based upon the differences between the financial statement carrying amounts and the tax bases of existing assets and liabilities and for loss and credit carryforwards, using enacted tax rates expected to be in effect in the year in which the differences are expected to reverse. Deferred tax assets are reduced by a valuation allowance if it is not more likely than not that these assets will be realized. The Company accrues liabilities for potential payments of tax to various tax authorities related to uncertain tax positions. Liabilities are based on a determination of whether and how much of a tax benefit taken by the Company in its tax filings or positions is more likely than not to be realized following resolution of any potential uncertainties related to the tax benefit. Potential interest and penalties associated with such uncertain tax positions are recorded as a component of the provision for income taxes, if applicable. As of December 31, 2020 and 2019, the Company identified $7.9 million and $6.8 million of gross uncertain tax positions, respectively. Included in those balances as of December 31, 2020 and 2019 are $3.7 million and $3.6 million of tax benefits, respectively, that, if recognized, would impact the effective tax rate. These have been accrued for as long-term liabilities on the Company’s consolidated balance sheets. Operating Segments The Company operates as one operating segment. Operating segments are defined as components of an enterprise for which separate financial information is regularly evaluated by the chief operating decision maker (“CODM”), which is the Company’s chief executive officer, in deciding how to allocate resources and assess performance. The Company’s CODM evaluates the Company’s financial information for the purpose of allocating resources and assessing the performance of these resources on a consolidated basis. Revenue by geographic country, based on ship-to destinations, which in certain instances may be the location of a contract manufacturer rather than the Company’s end customer, was as follows (in thousands): Year Ended December 31, 2020 2019 2018 United States $ 98,010 $ 70,702 $ 56,839 China 136,250 159,637 98,906 Germany 30,537 57,657 58,711 Thailand 191,219 82,413 68,217 Other 127,435 94,254 57,218 Total revenue $ 583,451 $ 464,663 $ 339,891 Total long-lived assets by geographic country consisted of the following as of December 31, 2020 and 2019 (in thousands): December 31, 2020 2019 United States $ 19,458 $ 18,325 Thailand 5,036 3,870 China 1,475 1,949 Other 1,945 2,657 Total long-lived assets $ 27,914 $ 26,801 Recently Adopted Accounting Pronouncements In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standard Update (“ASU”) 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”). ASU 2016-13 is intended to provide more decision-useful information about expected credit losses on financial instruments, including trade receivables, and other commitments to extend credit held by a reporting entity at each reporting date. The main provisions include presenting financial assets measured at amortized cost at the amount expected to be collected, which is net of an allowance for expected credit losses, and recording credit losses related to available-for-sale securities through an allowance for credit losses. On January 1, 2020, the Company adopted ASU 2016-13 using the modified retrospective approach. There was no impact from the adoption of ASU 2016-13 on the Company’s consolidated financial statements. The Company is exposed to credit losses through sales of its products. The Company determines if there is an expected loss on its accounts receivables using historical collection experience, current and future economic and market conditions and a review of the current status of customers' trade accounts receivables. The Company has recorded an immaterial amount of allowance for credit losses as of December 31, 2020 and December 31, 2019. Refer to Note 5 for information regarding how the Company assesses credit losses on its available-for-sale debt securities. Recently Issued Accounting Pronouncements In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes (“ASU 2019-12”). ASU 2019-12 is intended to simplify the accounting for income taxes by, among other things, removing certain exceptions related to the approach for intraperiod tax allocation, the methodology for calculating income taxes in an interim period when a year-to-date loss exceeds the anticipated loss for the year and the recognition of deferred tax

REVENUE

REVENUE	12 Months Ended
	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
REVENUE	REVENUE Revenue for product sales is recognized at the point in time when control transfers to the Company’s customers, which is generally when products are shipped from the Company’s manufacturing facilities or when delivered to the customer’s named location. When the Company performs shipping and handling activities after the transfer of control to the customer (e.g., when control transfers prior to delivery), they are considered to be fulfillment activities, and accordingly, the costs are accrued for when the related revenue is recognized. Taxes collected on behalf of customers relating to product sales and remitted to governmental authorities, principally sales taxes, are excluded from revenue. The opening and closing balances of the Company’s accounts receivable and deferred revenue are as follows (in thousands): Balance at Beginning of Period (1/1/20) Increase / (Decrease) Balance at End of Period Year Ended December 31, 2020 Accounts receivable $ 97,948 $ 20,466 $ 118,414 Deferred revenue (current) $ 4,483 $ 1,271 $ 5,754 Deferred revenue (non-current) $ 3,444 $ (3,444) $ — The amount of revenue recognized in the period that was included in the opening deferred revenue balances was approximately $3.8 million for the year ended December 31, 2020. Generally, increases in current and non-current deferred revenue are related to billings to, or advance payments from, customers for which the Company has not yet fulfilled its performance obligations, and decreases are related to revenue recognized. Deferred revenue not expected to be recognized within the Company’s operating cycle of one year is presented as a component of “Other long-term liabilities” on the consolidated balance sheet. At times, the Company receives orders for products that may be delivered over multiple dates that may extend across reporting periods. The Company invoices for each delivery upon shipment and recognizes revenues for each distinct product delivered, assuming transfer of control has occurred. Generally, scheduled delivery dates are within one year, and the Company has elected to use the optional exemption whereby revenues allocated to partially completed contracts with an expected duration of one year or less are not disclosed. As of December 31, 2020, the Company had no contracts with unsatisfied performance obligations with a duration of more than one year. Disaggregation of Revenue The following table provides information about disaggregated revenue based on product group (in thousands). Further disaggregation of revenue by geographic country can be found in Note 3. Year Ended Year Ended Year Ended December 31, 2020 December 31, 2019 December 31, 2018 Revenue ($) Revenue (%) Revenue ($) Revenue (%) Revenue ($) Revenue (%) Embedded Modules $ 222,448 38 % $ 86,932 19 % $ 77,286 23 % Pluggable Modules 226,280 39 % 217,620 47 % 189,533 56 % Semiconductors 134,723 23 % 160,111 34 % 73,072 21 % Total revenue $ 583,451 100 % $ 464,663 100 % 339,891 100 %

FINANCIAL INSTRUMENTS

FINANCIAL INSTRUMENTS	12 Months Ended
	Dec. 31, 2020
Investments, Debt and Equity Securities [Abstract]
FINANCIAL INSTRUMENTS	FINANCIAL INSTRUMENTS The following tables set forth the Company’s cash, cash equivalents and short- and long-term marketable securities as of December 31, 2020 and 2019 (in thousands): December 31, 2020 Amortized Cost Gross Unrealized Estimated Fair Value Cash and Cash Marketable Gains Losses (1) Cash $ 90,160 $ — $ — $ 90,160 $ 90,160 $ — Money market funds 7,451 — — 7,451 7,451 — U.S. treasury bonds 79,064 169 — 79,233 12,300 66,933 Commercial paper 82,261 5 (1) 82,265 7,997 74,268 Certificates of deposit 17,027 9 — 17,036 — 17,036 Asset-backed securities 60,475 98 (7) 60,566 — 60,566 Corporate debt securities 253,784 331 (65) 254,050 3,777 250,273 Total $ 590,222 $ 612 $ (73) $ 590,761 $ 121,685 $ 469,076 (1) Losses represent marketable securities that were in loss positions for less than one year. December 31, 2019 Amortized Cost Gross Unrealized Estimated Fair Value Cash and Cash Marketable Gains Losses (1) Cash $ 29,116 $ — $ — $ 29,116 $ 29,116 $ — Money market funds 2,010 — — 2,010 2,010 — U.S. treasury bonds 116,710 126 (1) 116,835 — 116,835 Commercial paper 44,300 — — 44,300 5,491 38,809 Certificates of deposit 24,522 19 (2) 24,539 — 24,539 Asset-backed securities 73,370 134 (5) 73,499 — 73,499 Corporate debt securities 180,607 475 (3) 181,079 — 181,079 Total $ 470,635 $ 754 $ (11) $ 471,378 $ 36,617 $ 434,761 (1) Losses represent marketable securities that were in loss positions for less than one year. The proceeds from the sales and maturities of marketable securities, which were primarily reinvested and resulted in realized gains and losses, were as follows (in thousands): Year Ended December 31, 2020 2019 2018 Proceeds from the sales and maturities of marketable securities $ 383,667 $ 384,467 $ 340,920 Realized gains $ 125 $ 67 $ 18 Realized losses $ — $ (2) $ (109) The contractual maturities of short-term and long-term marketable securities held at December 31, 2020 and 2019 are as follows (in thousands): December 31, 2020 December 31, 2019 Amortized Cost Basis Aggregate Fair Value Amortized Cost Basis Aggregate Fair Value Due within one year $ 297,772 $ 298,185 $ 299,725 $ 300,129 Due after one year through four years 170,763 170,891 134,292 134,632 Total $ 468,535 $ 469,076 $ 434,017 $ 434,761 At December 31, 2020, the Company believed that none of its unrealized losses on its available-for-sale investments were attributable to credit losses and therefore were not impaired. The investments with unrealized losses consisted primarily of corporate debt securities. In making the determination that the decline in fair value of these securities did not indicate impairment, the Company considered various factors, including, but not limited to: the extent to which fair value was less than cost; the financial condition and near-term prospects of the issuers; and the Company’s intent not to sell these securities and the assessment that it is more likely than not that the Company would not be required to sell these securities before the recovery of their amortized cost basis. Unrealized gains and losses, net of taxes, are reported as a component of accumulated other comprehensive income (loss) in the Company’s consolidated statements of stockholders’ equity. No material amounts were reclassified out of accumulated other comprehensive income (loss) during the years ended December 31, 2020, 2019 and 2018 for realized gains or losses on available-for-sale investments.

INVENTORY

INVENTORY	12 Months Ended
	Dec. 31, 2020
Inventory Disclosure [Abstract]
INVENTORY	INVENTORY Inventory consisted of the following as of December 31, 2020 and 2019 (in thousands): December 31, 2020 2019 Raw materials $ 21,593 $ 24,777 Work-in-process 153 673 Finished goods 16,235 15,370 Inventory $ 37,981 $ 40,820

PROPERTY AND EQUIPMENT

PROPERTY AND EQUIPMENT	12 Months Ended
	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
PROPERTY AND EQUIPMENT	PROPERTY AND EQUIPMENT Property and equipment consisted of the following as of December 31, 2020 and 2019 (in thousands): December 31, 2020 2019 Engineering laboratory equipment $ 67,688 $ 58,320 Computer software 3,961 3,730 Computer equipment 9,483 7,837 Furniture and fixtures 3,641 3,641 Leasehold improvements 4,307 3,999 Construction in progress 2,912 2,449 Total property and equipment 91,992 79,976 Less: Accumulated depreciation (64,078) (53,175) Property and equipment, net $ 27,914 $ 26,801 Depreciation expense was $11.1 million, $12.6 million and $13.6 million for the years ended December 31, 2020, 2019 and 2018, respectively.

ACCRUED LIABILITIES

ACCRUED LIABILITIES	12 Months Ended
	Dec. 31, 2020
Payables and Accruals [Abstract]
ACCRUED LIABILITIES	ACCRUED LIABILITIESAccrued liabilities consisted of the following as of December 31, 2020 and 2019 (in thousands): December 31, 2020 2019 Employee-related liabilities $ 8,598 $ 10,816 Current maturities of operating leases 4,411 4,228 Goods and services received not invoiced 4,251 2,297 Accrued manufacturing related expenses 1,218 3,781 Warranty reserve 9,530 10,354 Litigation and settlement accrual 28,000 20,000 Other accrued liabilities 6,220 10,204 Accrued liabilities $ 62,228 $ 61,680

LEASES

LEASES	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
LEASES	LEASES The Company leases real estate assets and equipment. For leases with terms greater than 12 months, the Company records the related right-of-use (“ROU”) asset and lease obligation at the present value of lease payments over the term. Many leases include fixed rental escalation clauses, renewal options and/or termination options that are factored into the determination of lease payments when appropriate. The Company’s leases do not usually provide a readily determinable implicit discount rate; therefore, an estimate of the Company’s incremental borrowing rate is used to discount the lease payments based on information available at lease commencement, including observable rates, adjusted for various factors including financing spreads and other lease specific adjustments, as applicable. The Company has elected not to record an ROU asset and lease obligation for short-term leases (with terms less than 12 months) or separate non-lease components from associated lease components for its real estate lease assets. The Company’s leases have remaining lease terms of less than one year to eight years. Some leases include one or more options to renew with renewal terms that can extend the lease term from three years to five years, or options to terminate the leases, both at the Company’s discretion. The Company’s lease terms include options to extend or terminate leases when the Company concludes it is reasonably certain that it would exercise those options. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term. The Company’s lease agreements do not contain any variable lease payments, material residual value guarantees or material restrictive covenants. The table below presents the lease-related assets and liabilities recorded on the consolidated balance sheet as of December 31, 2020 (in thousands): Classification on the Balance Sheet December 31, 2020 Assets Operating lease assets Operating lease right-of-use assets $ 28,483 Liabilities Current - operating Accrued liabilities 4,411 Noncurrent - operating Noncurrent operating lease liabilities 18,099 Total lease liabilities $ 22,510 Weighted-average remaining lease term - operating leases 6.0 years Weighted-average discount rate - operating leases(1) 4.21 % (1) Upon adoption of ASC 842, discount rates used for existing leases were established at January 1, 2019, which was the date of the Company’s initial adoption of ASC 842. Operating lease costs were $6.0 million and $5.6 million during the years ended December 31, 2020 and 2019, respectively. Short-term lease costs during the years ended December 31, 2020 and 2019 were immaterial. Cash paid for amounts included in the measurement of lease liabilities was $4.5 million and $5.3 million during the years ended December 31, 2020 and 2019, respectively, which were operating cash outflows. The table below reconciles the undiscounted cash flows for each of the first five years and total of the remaining years to the operating lease liabilities recorded on the consolidated balance sheet as of December 31, 2020 (in thousands): Operating Leases 2021 $ 4,518 2022 4,338 2023 4,493 2024 4,510 2025 2,373 Thereafter 4,619 Total minimum lease payments 24,851 Less: amount of lease payments representing interest (2,341) Present value of future minimum lease payments 22,510 Less: current obligation under leases 4,411 Long-term lease obligations $ 18,099

FAIR VALUE MEASUREMENT

FAIR VALUE MEASUREMENT	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENT	FAIR VALUE MEASUREMENT The Company measures certain financial assets and liabilities at fair value. Fair value is determined based upon the exit price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants, as determined by either the principal market or the most advantageous market. Inputs used in the valuation techniques to derive fair values are classified based on a three-level hierarchy, as follows: Level 1 —Quoted prices (unadjusted) in active markets for identical assets or liabilities. Level 2 —Observable inputs other than Level 1 prices such as quoted prices for similar assets or liabilities, quoted prices in markets with insufficient volume or infrequent transactions (less active markets), or model-derived valuations in which all significant inputs are observable or can be derived principally from or corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 —Unobservable inputs to the valuation methodology that are significant to the measurement of fair value of assets or liabilities. The Company considers all highly liquid investments purchased with an original maturity of three months or less to be cash equivalents. The Company’s investments are in money market funds, U.S. treasury bonds, commercial paper, certificates of deposit, asset-backed securities and corporate debt securities, which are classified as Level 2 within the fair value hierarchy, and were initially valued at the transaction price and subsequently valued at each reporting date utilizing market-observable data. The market-observable data included reportable trades, benchmark yields, credit spreads, broker/dealer quotes, bids, offers, current spot rates and other industry and economic events. The fair value of these assets measured on a recurring basis was determined using the following inputs as of December 31, 2020 and 2019 (in thousands): December 31, 2020 Quoted Significant Significant Total Fair Assets: Money market funds $ — $ 7,451 $ — $ 7,451 U.S. treasury bonds — 79,233 — 79,233 Commercial paper — 82,265 — 82,265 Certificates of deposit — 17,036 — 17,036 Asset-backed securities — 60,566 — 60,566 Corporate debt securities — 254,050 — 254,050 Total $ — $ 500,601 $ — $ 500,601 December 31, 2019 Quoted Significant Significant Total Fair Assets: Money market funds $ — $ 2,010 $ — $ 2,010 U.S. treasury bonds — 116,835 — 116,835 Commercial paper — 44,300 — 44,300 Certificates of deposit — 24,539 — 24,539 Asset-backed securities — 73,499 — 73,499 Corporate debt securities — 181,079 — 181,079 Total $ — $ 442,262 $ — $ 442,262 There were no transfers between fair value measurement levels during the years ended December 31, 2020 and 2019. For certain other financial instruments, including accounts receivable, accounts payable and other current liabilities, the carrying amounts approximate their fair value due to the relatively short maturity of these balances.

STOCK COMPENSATION PLANS

STOCK COMPENSATION PLANS	12 Months Ended
	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
STOCK COMPENSATION PLANS	STOCK COMPENSATION PLANS The following table summarizes the classification of stock-based compensation in the consolidated income statements for the years ended December 31, 2020, 2019 and 2018 (in thousands): Year Ended December 31, 2020 2019 2018 Cost of revenue $ 2,089 $ 2,047 $ 2,075 Research and development 21,499 21,383 17,564 Sales, general and administrative 10,075 11,723 9,975 Total stock-based compensation $ 33,663 $ 35,153 $ 29,614 The following table summarizes stock-based compensation expense by award type for the years ended December 31, 2020, 2019 and 2018 (in thousands): Year Ended December 31, 2020 2019 2018 Restricted stock units $ 32,585 $ 31,811 $ 25,864 Stock options 492 1,902 2,343 Employee stock purchase plan — 1,119 1,284 Other awards 586 321 123 Total stock-based compensation $ 33,663 $ 35,153 $ 29,614 2009 Stock Plan In November 2009, the Company adopted the 2009 Stock Plan, as amended in October 2015 and March 2016 (the “2009 Plan”). The 2009 Plan provided for the grant of incentive stock options, nonstatutory stock options, RSUs and the right to purchase restricted common stock to employees, officers, directors and advisors of the Company. Recipients of incentive stock options and nonstatutory stock options are eligible to purchase shares of the Company’s common stock at an exercise price equal to the estimated fair value of such stock on the grant date. Stock options and RSUs granted under the 2009 Plan generally vest as follows (1) 20% on the first anniversary of the original vesting date, with the balance vesting monthly over the remaining four years or (2) 25% on the first anniversary of the original vesting date, with the balance vesting monthly or quarterly over the remaining three years, unless they contain specific performance and/or market-based vesting provisions. The maximum term of stock options and RSUs granted under the 2009 Plan is ten The 2016 Equity Incentive Plan (the “2016 Plan”) became effective on May 12, 2016, at which time the Company ceased granting equity awards under the 2009 Plan. The then outstanding equity awards granted under the 2009 Plan remain outstanding, subject to the terms of the 2009 Plan and applicable award agreements, until such shares are issued under those awards, by exercise of stock options or settlement of restricted awards, or until the awards terminate or expire by their terms. When the 2016 Plan became effective, there were 497,302 remaining shares available for grant under the 2009 Plan which were added to the reserves of the 2016 Plan. 2016 Equity Incentive Plan The 2016 Plan provides for the grant of incentive stock options, nonstatutory stock options, stock appreciation rights, restricted stock awards, RSUs and other stock-based awards. Recipients of incentive stock options and nonstatutory stock options are eligible to purchase shares of the Company’s common stock at an exercise price equal to the fair value of such stock on the grant date. Stock options and RSUs granted under the 2016 Plan generally vest 25% on the first anniversary of the original vesting date, with the balance vesting quarterly or annually over the remaining three years, unless they contain specific performance and/or market-based vesting provisions. The maximum term of stock options granted under the 2016 Plan is ten years. The 2016 Plan will terminate ten years from the effective date, unless it is terminated earlier by the Company’s board of directors. As of December 31, 2020, there were 4,764,927 shares available for future issuance. The number of shares reserved for issuance under the 2016 Plan will increase automatically on the first day of each January through 2025 equal to the least of (i) 3,600,000 shares of Common Stock, (ii) 4.0% of the outstanding shares on such date and (iii) an amount determined by the board of directors. In December 2020, the board of directors approved an increase in the number of shares available for issuance under the 2016 Plan in accordance with the automatic annual increase provisions of the 2016 Plan. Inclusive of this approved increase, a maximum of 11,228,533 shares of the Company’s common stock are authorized or available for issuance under the 2016 Plan. Stock Options The estimated grant-date fair value of the Company’s stock option awards issued to employees was calculated using the Black-Scholes option-pricing model. No stock options were granted in the years ended December 31, 2020 and 2019. During the year ended December 31, 2018, the assumptions used in the Black-Scholes model were as follows: Year Ended December 31, 2018 Risk-free interest rate 2.9% Expected dividend yield None Expected volatility 53.5% Expected term (in years) 6.3 Risk-free Interest Rate. The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the time of grant for zero coupon U.S. Treasury notes with maturities approximately equal to the option’s expected term. Expected Dividend Yield. The expected dividend yield assumption is based on the fact that the Company has never paid cash dividends and has no present intention to pay cash dividends. Expected Volatility. For options awarded during 2018, the expected volatility was derived from a blend of average historical stock volatilities of several unrelated public companies within the Company’s industry and the Company’s historical volatility, both over a period equivalent to the expected term of the stock option grants. Expected Term. The expected term represents the period that stock options awards are expected to be outstanding. For option grants that are considered to be “plain vanilla,” the Company determines the expected term using the simplified method. The simplified method deems the term to be the average of the time-to-vesting and the contractual life of the options. The Company uses the simplified method because it does not have sufficient historical option exercise data to provide a reasonable basis upon which to estimate the expected term. The Company uses the market closing price of its common stock as reported on The Nasdaq Global Select Market to determine the fair value of the shares of common stock underlying stock options. A summary of stock option activity under the Company’s equity incentive plans for the year ended December 31, 2020 is as follows: Number of Weighted-Average Weighted-Average Aggregate Outstanding at December 31, 2019 715 $ 11.14 4.6 $ 41,036 Granted — $ — Exercised (161) $ 13.57 $ 8,889 Canceled — $ 13.38 Outstanding at December 31, 2020 554 $ 10.43 3.3 $ 35,116 Vested and expected to vest at: December 31, 2020 554 $ 10.43 3.3 $ 35,116 Exercisable at: December 31, 2020 551 $ 10.31 3.3 $ 34,950 As of December 31, 2020 and 2019, there was $0.1 million and $0.5 million of unrecognized compensation cost related to unvested common stock options, which is expected to be recognized over weighted-average periods of 1.3 years and 0.6 years, respectively. The weighted-average grant date fair value of stock options granted during the year ended December 31, 2018 was $15.58. No stock options were granted by the Company during the years ended December 31, 2020 and 2019. The intrinsic value of stock options exercised during the years ended December 31, 2020, 2019 and 2018 was $8.9 million, $18.5 million and $15.9 million, respectively. Restricted Stock Units During the year ended December 31, 2019, the Company granted awards covering up to a maximum of 187,234 performance-based RSUs to executive officers that include a market condition in addition to a service condition (“2019 PRSUs”). Each 2019 PRSU represents the right to receive one share of the Company’s common stock when and if the applicable vesting conditions are satisfied. The 2019 PRSUs are subject to performance-based vesting. The number of 2019 PRSUs that vest is measured based on the level of achievement of a performance objective over a three For the 2019 PRSUs, the related stock-based compensation expense is amortized using the accelerated method over the vesting period of approximately three years. The Company estimated the fair value of the 2019 PRSUs using a Monte Carlo valuation model on the date of grant, using the following assumptions: Risk-free interest rate 2.5% Expected dividend yield None Expected volatility 57.3% Expected term (in years) 2.9 Grant date fair value of underlying shares $44.43 During the year ended December 31, 2018, the Company granted awards covering up to a maximum of 94,854 performance-based RSUs to executive officers that include a market condition in addition to a service condition (“2018 PRSUs”). Each 2018 PRSU represents the right to receive one share of the Company’s common stock when and if the applicable vesting conditions are satisfied. The 2018 PRSUs are subject to performance-based vesting. The number of 2018 PRSUs that vest is measured based on the level of achievement of a performance objective over a three-year period (the “2018 Performance Period”) running from January 1, 2018 through December 31, 2020, as determined and certified by the compensation committee of the Company’s board of directors following the end of the 2018 Performance Period. The level of achievement will be determined based on the Company’s percentile achievement of relative total shareholder returns against an external comparator group during the 2018 Performance Period (the “2018 Relative TSR Objective”). Vesting of the 2018 PRSUs is also subject to the applicable officer’s continued provision of services to the Company through the vesting date, except in the case of death or disability where vesting will be pro-rated for time worked during the 2018 Performance Period. No 2018 PRSUs will vest unless a threshold level of achievement of the 2018 Relative TSR Objective is achieved. The 2018 PRSUs vested on January 15, 2021. Refer to Note 19 for additional information. For the 2018 PRSUs, the related stock-based compensation expense is amortized using the accelerated method over the vesting period of approximately three years. The Company estimated the fair value of the 2018 PRSUs using a Monte Carlo valuation model on the date of grant, using the following assumptions: Risk-free interest rate 2.3% Expected dividend yield None Expected volatility 51.4% Expected term (in years) 2.9 Grant date fair value of underlying shares $34.59 - $39.02 RSUs with only a service condition is determined using the fair value of the Company’s common stock on the date of grant, and compensation is recognized on a ratable basis over the requisite vesting period. As soon as practicable following each vesting date of RSUs, the Company will issue to the holder of the RSUs, the number of shares of common stock equal to the aggregate number of RSUs that have vested. Notwithstanding the foregoing, the Company may, in its sole discretion, in lieu of issuing shares of common stock to the holder of the RSUs, pay the holder an amount in cash equal to the fair market value of such shares of common stock. To date, the Company has not settled any vested RSUs with cash. A summary of the changes in the Company’s RSUs during the year ended December 31, 2020 is as follows: Restricted Shares Weighted-Average Outstanding at December 31, 2019 1,951 $ 48.69 Granted 204 $ 68.17 Vested (736) $ 44.05 Canceled (30) $ 51.12 Outstanding at December 31, 2020 1,389 $ 53.96 At December 31, 2020 and 2019, there was $49.9 million and $70.1 million of total unrecognized compensation cost related to unvested RSUs, which will be recognized over weighted-average periods of 1.9 years and 2.1 years, respectively. Amended and Restated 2016 Employee Stock Purchase Plan The Company’s board of directors adopted the Amended and Restated 2016 Employee Stock Purchase Plan (“2016 ESPP”), which became effective on May 18, 2016. The 2016 ESPP allows eligible employees to purchase shares of the Company’s common stock at a discount through payroll deductions of up to 15% of eligible compensation, subject to any plan limitations. The 2016 ESPP provides for 6-month offering periods beginning in May and November of each year. On each purchase date, eligible employees purchase common stock at a price per share equal to 85% of the lesser of the fair market value of the Company’s common stock on (1) the first trading day of the applicable offering period and (2) the last trading day of the applicable offering period. The fair value of the awards issued under the 2016 ESPP to employees was estimated at the beginning of the offering period using a Black-Scholes option-pricing model with the following assumptions: Year Ended December 31, 2019 2018 Risk-free interest rate 2.4% - 2.5% 1.3% - 2.1% Expected dividend yield None None Expected volatility 38.9% - 45.5% 48.6% - 66.4% Expected term (in years) 0.5 0.5 In accordance with the Original Merger Agreement, the 2016 ESPP was suspended on November 14, 2019, the last day of the first offering period following the Original Merger Agreement effective date. Conditioned on the consummation of the Merger, no new offering periods are expected to commence on or after the suspension date. Preferred Stock The Company has authorized the issuance of preferred stock with rights and preferences, including voting rights, designated from time to time by the board of directors. As of December 31, 2020, there were 5,000,000 shares of preferred stock authorized with a par value of $0.0001 per share, and no shares of preferred stock issued or outstanding.

NET INCOME PER SHARE

NET INCOME PER SHARE	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
NET INCOME PER SHARE	NET INCOME PER SHARE The following table sets forth the computation of the Company’s basic and diluted net income per share (in thousands, except per share amounts): Year Ended December 31, 2020 2019 2018 Numerator: Net income $ 90,391 $ 32,839 $ 4,916 Denominator: Weighted-average shares used to compute net income per share - basic 41,938 40,883 40,259 Dilutive effect of stock options, unvested restricted stock and restricted stock units, and employee stock purchase plan 1,295 1,671 1,738 Weighted-average shares used to compute net income per share - diluted 43,233 42,554 41,997 Net income per share Basic $ 2.16 $ 0.80 $ 0.12 Diluted $ 2.09 $ 0.77 $ 0.12 The following common stock equivalents (in thousands) were excluded from the computation of diluted net income per share for the periods presented because including them would have been antidilutive: Year Ended December 31, 2020 2019 2018 Options to purchase common stock 14 37 91 Unvested restricted stock units 1 86 336 Employee stock purchase plan — — 1 Estimates of the number of shares contingently issuable based on average market prices through December 31, 2020 for all outstanding performance-based RSUs that include a market condition in addition to a service condition have been included in the antidilutive table above.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Warranties The Company’s standard warranty obligation to its customers provides for repair or replacement of a defective product at the Company’s discretion for a period of time following purchase, generally between 12 and 24 months. Factors that affect the warranty obligation include product failure rates, material usage and service delivery costs incurred in correcting product failures. In addition, from time to time, specific warranty accruals may be made if unforeseen technical problems arise. The estimated cost associated with fulfilling the Company’s warranty obligation to customers is recorded in cost of revenue. Changes in the Company’s warranty liability, which is included as a component of accrued liabilities on the consolidated balance sheets, are set forth in the table below (in thousands): Year Ended December 31, 2020 2019 2018 Warranty reserve, beginning of period $ 10,354 $ 8,220 $ 8,306 Provisions made to warranty reserve during the period 7,689 13,708 11,775 Charges against warranty reserve during the period (8,513) (11,574) (11,861) Warranty reserve, end of period $ 9,530 $ 10,354 $ 8,220 Legal Contingencies On January 21, 2016, ViaSat, Inc. (“ViaSat”) filed a lawsuit in California state court, 37-2016-00002323-CU-BC-NC, later removed to the U.S. District Court for the Southern District of California, against the Company alleging, among other things, breach of contract, breach of the implied covenant of good faith and fair dealing and misappropriation of trade secrets. On February 19, 2016, the Company responded to ViaSat’s lawsuit and alleged counterclaims against ViaSat including, among other things, patent misappropriation, breach of contract, breach of the implied covenant of good faith and fair dealing, misappropriation of trade secrets and unfair competition. In its response filed March 16, 2016, ViaSat denied the Company’s counterclaims. On September 28, 2018 the matter was remanded back to the California Superior Court, County of San Diego, North County Division 3:16-cv-00463, D.I. 197. In April 2019, the California Superior Court denied the parties’ cross motions for summary adjudication. At the court’s direction, the parties participated in a mandatory mediation process, but no resolution was reached. Trial took place in June and July of 2019, and the jury returned a verdict on July 17, 2019. The jury found against the Company for breach of contract, willful and malicious misappropriation of trade secrets, and breach of the covenant of good faith and fair dealing implied by law in the parties’ contract. The jury also found that ViaSat breached the same contract and misappropriated the Company’s trade secrets. The jury awarded damages of $49.3 million to ViaSat for the Company’s breaches of contract, and $1 to ViaSat for its trade secret misappropriation claim. The jury awarded $1 to the Company for ViaSat’s misappropriation of trade secrets and awarded no damages to the Company for ViaSat’s breach of contract. ViaSat filed post-trial motions seeking up to approximately $10.0 million for attorney’s fees and approximately $6.2 million for so-called “cost-of-proof” sanctions and an order that the Company pay ViaSat ongoing royalties on sales after December 31, 2018. ViaSat also sought a new trial and judgment in its favor notwithstanding the verdict on its trade secret damages claim. The Company filed post-trial motions for entry of judgment in its favor notwithstanding the verdict on ViaSat’s breach of contract and trade secret damages claims and for a new trial, and moved to reduce the total damages awarded to ViaSat to no more than $12.8 million pursuant to a provision of the contract containing a limitation on liability for claims arising from the contract. The Court denied the post-trial motions filed by both parties, and on December 5, 2019, the Court entered judgment (the “December 2019 Judgment”) against the Company in the amount of $49.3 million, and against ViaSat in the amount of $1. On January 17, 2020, the Court awarded ViaSat an additional $0.1 million in costs. On December 20, 2019, the Company filed a notice of appeal of the December 2019 Judgment, and ViaSat filed a notice of cross-appeal on December 26, 2019. The parties’ respective appeals are pending and the Company filed its opening appellate brief on August 19, 2020. ViaSat filed its combined response brief in the Company’s appeal and opening brief in its cross-appeal on January 13, 2021. The Company’s combined reply brief in its appeal and response brief in ViaSat’s cross-appeal is currently due April 2, 2021. As of December 31, 2020, the Company has accrued a total of $28.0 million in litigation and settlement-related accruals. The amount of such accruals is based upon currently available information and is subject to significant judgment and a variety of assumptions and known and unknown uncertainties, which may change quickly and significantly from time to time. As a result, actual losses could significantly exceed the amount of such accruals, and no conclusion as to the Company’s ultimate exposure from these proceedings should be drawn from such accruals. In view of the numerous legal, technical and factual issues involved in this lawsuit, the Company is not able to provide an estimate of the likely outcome or range of outcomes, if any, at this time. On November 6, 2019, ViaSat filed a second lawsuit in California Superior Court, County of San Diego, North County Division, 37-2019-00060731, D.I. 01, against the Company alleging breach of contract, breach of the implied covenant of good faith and fair dealing, and misappropriation of trade secrets. ViaSat’s complaint relies on the verdict in the first lawsuit, seeks damages on sales of the Company’s products after December 31, 2018, and its claims for relief include preliminary and permanent injunctive relief prohibiting sales of the Company’s products alleged by ViaSat to misappropriate its trade secrets. On January 17, 2020, the Company responded to ViaSat’s second lawsuit with a general denial and moved to stay the case. On February 28, 2020, the court issued an order granting the Company’s motion to stay the case pending outcome of the appeal in the first lawsuit. In view of the numerous legal, technical and factual issues involved in this lawsuit, the Company is not able to provide an estimate of the likely outcome or range of outcomes, if any, at this time. On June 9, 2020, ViaSat filed a third lawsuit in California Superior Court, County of San Diego, North County Division, Case No. 37-2020-00019223, against the Company alleging breach of contract, breach of the implied covenant of good faith and fair dealing, and misappropriation of trade secrets. ViaSat’s complaint concerns different products than those involved in the first two suits. ViaSat claims such products also use ViaSat’s confidential information and trade secrets, and ViaSat’s claims for relief include damages and preliminary and permanent injunctive relief prohibiting sales of the Company’s products alleged by ViaSat to misappropriate its trade secrets. The Company filed a demurrer in response to the complaint on July 30, 2020 and the Court stayed the action until after the resolution of the appeal of the December 2019 Judgment. In view of the numerous legal, technical and factual issues involved in this lawsuit, the Company is not able to provide an estimate of the likely outcome or range of outcomes, if any, at this time. On July 28, 2017, the Company filed a lawsuit in the Commonwealth of Massachusetts Superior Court - Business Litigation Session against ViaSat asserting commercial disparagement, libel, slander of title, unfair competition, intentional interference with advantageous relations and intentional interference with contractual relations. On April 5, 2018, ViaSat responded to the Company’s action and alleged counterclaims including, among other things, breach of contract, breach of the implied covenant of good faith and fair dealing, misappropriation of trade secrets, and unfair competition. On December 13, 2018, the Massachusetts court entered an order staying the Massachusetts litigation pending resolution of the first California state court action discussed above. On December 12, 2019, the Massachusetts court entered an order continuing the stay of the Massachusetts litigation to and including July 10, 2020. On July 6, 2020, the Massachusetts court entered an order continuing the stay of the Massachusetts litigation to and including December 4, 2020. On December 7, 2020, the Massachusetts court entered an order continuing the stay of the Massachusetts litigation to and including March 31, 2021. The litigation matters described above are referred to collectively as the ViaSat litigation. The Company intends to continue to engage in a vigorous defense and pursuit of Company-favorable judgments of the ongoing litigation matters described above. The ultimate resolution of these proceedings may have a material adverse effect on the Company’s results of operations and cash flows, potentially in the near term. In addition, the timing of the final resolution of these proceedings is uncertain. The Company will continue to incur litigation and other expenses as a result of these proceedings, which could have a material impact on the Company’s business, consolidated financial position, results of operations and cash flows. In addition, from time to time the Company may become involved in legal proceedings or be subject to claims arising in the ordinary course of the Company’s business. Although the results of litigation and claims cannot be predicted with certainty, the Company currently believes that the final outcome of these ordinary course matters will not have a material adverse effect on the Company’s business or on the Company’s consolidated financial position, results of operations or cash flows. Regardless of the outcome, litigation can have an adverse impact on the Company because of defense and settlement costs, diversion of management resources and other factors. Surety Bond On December 20, 2019, the Company filed a Notice of Appeal to appeal the final judgment issued by the California Superior Court in the ViaSat litigation. In order to stay the execution of the final judgment pending its appeal, the Company filed a surety bond in the amount of $75.0 million as provided by California Code of Civil Procedure Sec. 917.1. The bond is issued by the Philadelphia Indemnity Insurance Company (“Philadelphia Indemnity”). In support of the bond, the Company entered into an indemnity agreement with Philadelphia Indemnity to indemnify it from any liability or loss under the bond. The indemnity agreement does not require collateral to be posted at the time of the issuance of the bond. However, Philadelphia Indemnity may on demand require deposit of an amount sufficient to fund any liability or loss. For additional information, see the discussion regarding the ViaSat litigation under “Legal Contingencies” above. Indemnification In the ordinary course of business, the Company enters into various agreements containing standard indemnification provisions. The Company’s indemnification obligations under such provisions are typically in effect from the date of execution of the applicable agreement through the end of the applicable statute of limitations. During the years ended December 31, 2020, 2019 and 2018, the Company incurred an immaterial amount of expenses related to these indemnification obligations. The Company does not anticipate significant claims related to these indemnification obligations, and consequently, has concluded that the fair value of these obligations is not material. Accordingly, as of December 31, 2020 and 2019, no material amounts have been accrued related to such indemnification provisions. Potential Payments upon Termination or Change in Control The Company’s Amended and Restated Severance and Change in Control Benefits Plan (the “Severance Plan”) provides severance benefits to the Company’s executive officers, including certain of the Company’s named executive officers, if the executive officer’s employment is terminated by the Company without “cause” (as defined in the Severance Plan) or if they terminate their employment with the Company for “good reason” (as defined in the Severance Plan), and additional severance benefits if such terminations occur within one year of a “change in control” (as defined in the Severance Plan) of the Company. For purposes of the Severance Plan, the Merger constituted a change in control of the Company. Under the Severance Plan, if the Company terminates an eligible executive officer’s employment without cause prior to or more than 12 months following the closing of a change in control of the Company (an “Involuntary Termination”), the executive officer is entitled to: • continue receiving his or her base salary for a specified period following the date of termination (in the case of the Company’s chief executive officer, for 12 months, and, in the case of all other participants, for nine months); • Company contributions to the cost of health care continuation under the Consolidated Omnibus Budget Reconciliation Act (“COBRA”), for U.S. based eligible executive officers, or substantially equivalent medical benefits for non-U.S. based eligible executive officers, for up to 12 months following the date of termination of employment (or, to the extent a non-U.S. based eligible executive officer is then receiving a stipend from the Company in lieu of benefits coverage, continued payment of such stipend for up to 12 months following the date of termination of employment); and • the amount of any unpaid annual bonus determined by the Company’s board of directors to be payable to the executive officer for any completed bonus period which ended prior to the date of such executive officer’s termination. In addition, under the terms of the Severance Plan, in the case of an Involuntary Termination, all the executive officer’s outstanding equity awards that vest solely based on the passage of time will be accelerated and become vested to the extent the award would have vested if the executive had remained employed through a specified period following the date of termination (in the case of the Company’s chief executive officer, for 12 months, and, in the case of all other participants, for nine months). The vesting of outstanding performance-based equity awards in connection with an Involuntary Termination is determined by the terms of the applicable award agreements. The Severance Plan also provides that, if, within 12 months following a change in control of the Company, the Company terminates an eligible executive officer’s employment without cause or such executive terminates his or her employment with the Company for good reason (a “Change in Control Termination”), the executive officer is entitled to the following benefits; provided, that each of Messrs. Shanmugaraj, Mikkelsen, Givehchi and Rasmussen have entered into employment agreements with Parent or its affiliates that became effective upon the Closing of the Merger and superseded the Severance Plan such that each of Messrs. Shanmugaraj, Mikkelsen, Givehchi and Rasmussen are not entitled to the following benefits upon a qualifying termination of employment following the Merger and are instead entitled to the benefits described under the heading “Severance/Change in Control Benefits and Employment and Retention Agreements” in the Company’s definitive proxy statement filed with the Securities and Exchange Commission on February 8, 2021: • a single lump-sum payment in an amount equal to a 100% of his or her annual base salary: • a single lump sum payment in an amount equal to 100% of his or her target annual bonus for the year in which the termination of employment occurs; • Company contributions to the cost of health care continuation under COBRA, for U.S. based eligible executive officers, or substantially equivalent medical benefits for non-U.S. based eligible executive officers, for up to 12 months following the date of termination of employment (or, to the extent a non-U.S. based eligible executive officer is then receiving a stipend from the Company in lieu of benefits coverage, continued payment of such stipend for up to 12 months following the date of termination of employment); and • the amount of any unpaid annual bonus determined by the Company’s board of directors to be payable to the executive officer for any completed bonus period which ended prior to the date of such executive officer’s termination. In addition, under the terms of the Severance Plan, in the case of a Change in Control Termination, all of the executive officer’s outstanding unvested time-based equity awards will immediately vest in full on the date of such termination. The vesting of outstanding performance-based equity awards in connection with a Change in Control Termination is determined in accordance with the terms of the applicable award agreements. Each executive officer is also entitled to certain severance benefits upon a termination due to death or disability (as described in the Severance Plan), which severance benefits are not enhanced in connection with a change in control of the Company. All payments and benefits provided under the Severance Plan are contingent upon the execution and effectiveness of a release of claims by the executive officer in the Company’s favor and continued compliance by the executive officer with any proprietary information and inventions, nondisclosure, non-competition, non-solicitation (or similar) agreement to which the Company and the executive officer are party.

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES Income Tax Provision (Benefit) The components of income (loss) before provision (benefit) for income taxes are as follows (in thousands): Year Ended December 31, 2020 2019 2018 United States $ (30,213) $ (62,991) $ (35,832) Foreign 125,056 84,632 35,428 Total $ 94,843 $ 21,641 $ (404) The components of the provision (benefit) for income taxes are as follows (in thousands): Year Ended December 31, 2020 2019 2018 Current income tax (benefit) provision Federal $ (1,071) $ 135 $ (9,417) State (49) 252 23 Foreign 2,904 1,667 921 Total current income tax provision (benefit) $ 1,784 $ 2,054 $ (8,473) Deferred income tax provision (benefit) Federal 7,176 (7,114) 2,944 State (4,056) (5,427) 480 Foreign (452) (711) (271) Total deferred income tax provision (benefit) 2,668 (13,252) 3,153 Total income tax provision (benefit) $ 4,452 $ (11,198) $ (5,320) The Company is subject to income tax in the United States as well as other tax jurisdictions in which it conducts business. Earnings from non-U.S. activities are subject to local country income tax. As a result of the concept of “deemed distributions” under the Tax Act, the impact of global intangible low-tax income (“GILTI”) on the Company’s future foreign earnings, and lack of certain foreign governments’ withholding tax imposed on dividends, the Company no longer takes the position that most of its foreign earnings are permanently reinvested. However, for certain foreign operating subsidiaries, the Company continues to take the position that earnings are permanently reinvested. As of December 31, 2020, there was $17.3 million of cumulative foreign earnings for which state income taxes have not been provided. Deferred Tax Assets and Liabilities Significant components of the Company’s net deferred tax assets at December 31, 2020 and 2019, are as follows (in thousands): December 31, 2020 2019 Deferred tax assets: Accrued expenses $ 10,001 $ 8,748 Net operating loss carryforwards 9,406 16,624 Credit carryforwards 39,640 32,498 Lease liability 5,479 4,690 Stock-based compensation 3,112 4,200 Other 1,003 808 Total deferred tax assets $ 68,641 $ 67,568 Deferred tax liabilities: Depreciation (1,046) (161) Right-of-use asset (6,939) (5,930) Other (346) (758) Total deferred tax liabilities (8,331) (6,849) Valuation allowance (11,228) (8,921) Net deferred tax assets $ 49,082 $ 51,798 The Company accounts for deferred taxes under ASC Topic 740, Income Taxes which involves weighing positive and negative evidence concerning the realizability of the Company’s deferred tax assets in each jurisdiction. The Company evaluated its ability to realize the benefit of its net deferred tax assets and weighed all available positive and negative evidence both objective and subjective in nature. In determining the need for a valuation allowance, the weight given to positive and negative evidence is commensurate with the extent to which the evidence may be objectively verified. Consideration was given to negative evidence such as the duration and severity of losses, as well as the expiration and limitation of tax attributes in various jurisdictions. As of December 31, 2020, positive evidence included consolidated three-year cumulative profitability of $116.1 million. Additionally, after determining that sufficient forecasted taxable income of appropriate character is expected to continue in future years, the Company believes the weight of the objectively verifiable positive evidence coupled with the subjective positive evidence from forecasted operating plans is sufficient to overcome the weight of any negative evidence. In the U.S. the GILTI provisions from the Tax Act have created U.S. taxable income and are expected to continue to do so in future years. During the year ended December 31, 2020, the Company concluded it is more likely than not that it will realize the benefit of $49.1 million of the Company’s net deferred tax assets. The Company maintains a partial valuation allowance of $11.2 million against certain U.S. deferred tax assets, which include federal net operating loss and credit carryforwards limited under IRC Section 382 as well as certain state net operating losses and credits accumulated in jurisdictions in which management does not anticipate sufficient taxable income to utilize the credits. Management will continue to assess the applicability of a valuation allowance at each reporting period. The table below summarizes changes in the deferred tax asset valuation allowance (in thousands): Year Ended December 31, Beginning Additions Reductions Ending 2018 $ 1,416 4,967 — $ 6,383 2019 $ 6,383 2,538 — $ 8,921 2020 $ 8,921 2,307 — $ 11,228 Tax Rate A reconciliation of the provision (benefit) for income taxes computed at the statutory federal income tax rate to the provision (benefit) for income taxes as reflected in the consolidated financial statements is as follows: Year Ended December 31, 2020 2019 2018 Provision for income taxes at statutory rate 21.0 % 21.0 % 21.0 % (Decreases) increases resulting from: Federal tax credits (8.1) (29.9) 1,304.6 Change in valuation allowance 2.4 11.7 (1,230.7) State tax expense, net of federal benefit (5.8) (36.4) 1,058.0 Meals and entertainment — 0.3 (24.0) Stock-based compensation expense (3.7) (26.8) 384.1 Change in uncertain tax positions 1.1 8.6 (116.5) Transition tax — — (9.6) APB23 state liability (0.4) (0.7) (2.0) Foreign rate differential (26.3) (77.3) 1,598.6 Foreign rate inclusion 25.1 84.0 (1,990.5) Other (0.6) (6.2) 323.8 Effective income tax rate 4.7 % (51.7) % 1,316.8 % For the year ended December 31, 2020, the Company recorded an income tax expense of $4.5 million, representing an effective tax rate of 4.7%. The effective tax rate differs from the U.S. statutory tax rate primarily as a result of the jurisdictional mix of earnings, stock-based compensation excess tax benefits, and federal and state research and development credits. Tax Attributes As of December 31, 2020, the Company had $1.3 million and $140.2 million of federal and state net operating loss carryforwards, respectively, that expire at various dates through 2040. In addition, federal net operating loss carryforwards generated after December 31, 2017 are subject to carryforward indefinitely. As of December 31, 2020, the Company had $21.0 million, $27.1 million and $1.9 million of federal, state and foreign research and development and other credit carryforwards, respectively, that expire at various dates through 2040. Realization of the future tax benefits is dependent on many factors, including the Company’s ability to generate taxable income within the net operating loss carryforward period. Utilization of some of the net operating loss carryforwards is subject to an annual limitation due to the ownership percentage change limitations provided by Section 382 of the Internal Revenue Code of 1986 and similar state provisions. The annual limitations will result in the expiration of $0.8 million of the federal net operating loss carryforwards before utilization. The Company performed an Internal Revenue Code Section 382 study and determined that utilization of its annual net operating losses for periods prior to 2014 are limited to approximately $4.8 million per year through 2017, $2.3 million in 2018 and $1.4 million in years thereafter in connection with changes in control in 2009 and 2013. The Company’s operating loss carryforwards for years after 2013 are not limited. Accounting for Uncertainty in Income Taxes The Company recognizes, in its consolidated financial statements, the effect of a tax position when it is more likely than not, based on the technical merits, that the position will be sustained upon examination. The aggregate changes in gross unrecognized tax benefits during the years ended December 31, 2020 and 2019 were as follows (in thousands): Balance at December 31, 2018 $ 4,974 Increases for the tax positions taken during the year 1,857 Balance at December 31, 2019 $ 6,831 Increases for the tax positions taken during the year 1,209 Decreases for tax positions reduced during the year due to statute expirations, etc. (173) Balance at December 31, 2020 $ 7,867 The Company had $7.9 million and $6.8 million of uncertain tax positions during the years ended December 31, 2020 and 2019, respectively. Included in the balance of unrecognized tax benefits as of December 31, 2020 and 2019 are $3.7 million and $3.6 million of tax benefits, respectively, that, if recognized, would impact the effective tax rate. These have been accrued for as long-term liabilities on the Company’s consolidated balance sheets. The Company’s existing tax positions are expected to continue to generate an increase in unrecognized tax benefits in subsequent periods. The Company’s policy is to record interest and penalties related to unrecognized tax benefits as income tax expense. There are no material amounts of interest or penalties recognized in the consolidated income statements or accrued on the consolidated balance sheets for any period presented. In the normal course of business, the Company is potentially subject to examination by tax authorities throughout the United States and other foreign jurisdictions in which the Company operates. All tax years since inception remain open to examination by the Internal Revenue Service (“IRS”) or state tax authorities, as carryforward attributes generated in prior period tax years may still be adjusted upon examination if they have or will be used in a future period. The Company also files foreign tax returns in the foreign jurisdictions in which it operates when required. The Company is currently being audited by the IRS for income tax years 2014 through 2017, and the state of New Jersey for income tax years 2015 through 2017. There are currently no foreign examinations in process. The Company expects to release federal and state reserves for unrecognized tax benefits between $3.0 million to $5.0 million in the first quarter of 2021 as a result of a favorable IRS audit settlement. On July 27, 2015, in Altera Corp. v. Commissioner, the U.S. Tax Court issued an opinion invalidating the regulations relating to the treatment of stock-based compensation expense in an intercompany cost-sharing arrangement. The Tax Court issued its final decision December 2015, and u nder Internal Revenue Code Section 7482(b), that decision was appealable to the Ninth Circuit Court of Appeals.The IRS appealed in June 2016 and after withdrawing an initial decision that would have affirmed the Tax Court, on June 7, 2019, the Court of Appeals reversed the 2015 decision of the Tax Court and upheld the cost-sharing regulations. The Court of Appeals denied Altera’s petition for rehearing on July 22, 2019, and the United States Supreme Court denied Altera’s petition for certiorari on June 22, 2020. The Tax Court will treat the Court of Appeals decision in Altera as precedential in cases that come before the Tax Court that are appealable to the Ninth Circuit Court of Appeals. If the Company were to challenge a proposed federal income tax deficiency in the Tax Court, however, any decision in its case would be appealable under Internal Revenue Code Section 7482(b) to the First Circuit Court of Appeals. In such a case, the Tax Court would be at liberty to follow its original decision in Altera. As a result, as of December 31, 2020, the Company has determined that the decision of the Ninth Circuit Court of Appeals does not require any adjustment to the Company’s consolidated financial statements. If the Company were to adjust its consolidated financial statements to reflect the impact of following the decision of the Ninth Circuit Court of Appeals in Altera, the Company estimates that the potential impact on its prior year tax liabilities would be as much as $6.3 million on a financial statement basis. On March 27, 2020, Congress enacted the Coronavirus Aid, Relief, and Economic Security (“CARES”) Act to provide certain relief as a result of the global spread of SARS-CoV-2 and COVID-19. The Company has evaluated the impact of the CARES Act and determined it to have an immaterial effect on the Company’s income tax position.

CONCENTRATIONS OF RISK

CONCENTRATIONS OF RISK	12 Months Ended
	Dec. 31, 2020
Risks and Uncertainties [Abstract]
CONCENTRATIONS OF RISK	CONCENTRATIONS OF RISK Customer Concentration Customers with revenue equal to or greater than 10% of total revenue for the years ended December 31, 2020, 2019 and 2018 were as follows: Year Ended December 31, 2020 2019 2018 A 17 % 27 % 20 % B * 13 % 15 % C 18 % 17 % 17 % E 18 % 17 % 14 % H 13 % * * __________________________________________________________________________________________ * Less than 10% of revenue in the period indicated Customers, which include their authorized contract manufacturers, that accounted for equal to or greater than 10% of accounts receivable at December 31, 2020 and 2019 were as follows: December 31, 2020 December 31, 2019 A 23 % 28 % B * 16 % G * 10 % I 27 % * __________________________________________________________________________________________ * Less than 10% of accounts receivable at the date indicated Supplier Concentration The Company’s most significant vendor spending is related to purchases from contract manufacturers and component suppliers located in China and Thailand, from which the Company purchases a substantial portion of its inventory. For the years ended December 31, 2020, 2019 and 2018, total purchases from each of the suppliers were as follows: Year Ended December 31, 2020 2019 2018 X 14 % 18 % 18 % Y 57 % 53 % 53 %

RETIREMENT PLAN

RETIREMENT PLAN	12 Months Ended
	Dec. 31, 2020
Retirement Benefits [Abstract]
RETIREMENT PLAN	RETIREMENT PLANThe Company is the sponsor of a defined contribution savings plan for all qualified employees under Section 401(k) of the Internal Revenue Code (the “401(k) Plan”). The 401(k) Plan allows participants to contribute a portion of their compensation on a pre-tax basis up to an amount not to exceed the annual statutory limit applicable to each individual participant. The Company is permitted to make discretionary matching contributions to the 401(k) Plan. Total matching contributions during the years ended December 31, 2020, 2019 and 2018 amounted to $2.2 million, $1.9 million and $1.6 million, respectively.

RELATED PARTIES

RELATED PARTIES	12 Months Ended
	Dec. 31, 2020
Related Party Transactions [Abstract]
RELATED PARTIES	RELATED PARTIES One of the members of the Company’s board of directors, Vincent Roche, is also the President and Chief Executive Officer and a member of the board of directors of Analog Devices, Inc. (“ADI”). The Company, through its contract manufacturers, periodically purchases supplies from ADI pursuant to purchase orders negotiated on an arm’s length basis between ADI and the Company’s contract manufacturers at prevailing prices. These purchased supplies are used as content in certain of the Company’s manufactured products. Based on shipments during the respective periods, the Company’s contract manufacturers made purchases from ADI of approximately $8.5 million, $4.1 million, and $3.8 million, during the years ended December 31, 2020, 2019 and 2018, respectively. Direct spending with ADI was immaterial for the years ended December 31, 2020, 2019 and 2018, respectively. In 2018, the Company entered into a product development agreement with ADI related to the development of integrated circuits for $1.5 million, of which $0.5 million, $0.3 million and $0.8 million of costs were incurred during the years ended December 31, 2020, 2019 and 2018, respectively. One of the members of the Company’s board of directors, Peter Y. Chung, is also a member of the board of directors of MACOM Technology Solutions, Inc. (“MACOM”). The Company, through its contract manufacturers, periodically purchases supplies from MACOM. These purchased supplies are used as content in certain of the Company’s manufactured products. Based on shipments, the Company’s contract manufacturers made no purchases from MACOM during the years ended December 31, 2020 and 2019, and $0.3 million of purchases from MACOM during the years ended December 31, 2018. Direct spending with MACOM was immaterial for the years ended December 31, 2020, 2019 and 2018, respectively.

UNAUDITED QUARTERLY FINANCIAL I

UNAUDITED QUARTERLY FINANCIAL INFORMATION	12 Months Ended
	Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
UNAUDITED QUARTERLY FINANCIAL INFORMATION	UNAUDITED QUARTERLY FINANCIAL INFORMATION 2020 First Second Third Fourth (in thousands) Revenue $ 125,626 $ 135,215 $ 158,456 $ 164,154 Cost of revenue 66,344 70,007 78,541 84,459 Gross profit 59,282 65,208 79,915 79,695 Operating expenses: Research and development 32,095 32,575 39,884 29,844 Sales, general and administrative 14,371 18,276 15,082 12,657 Total operating expenses 46,466 50,851 54,966 42,501 Income from operations 12,816 14,357 24,949 37,194 Total other income, net 2,250 1,591 995 691 Income before benefit for income taxes 15,066 15,948 25,944 37,885 (Benefit) provision for income taxes (578) (133) 1,655 3,508 Net income $ 15,644 $ 16,081 $ 24,289 $ 34,377 Net income per share: Basic $ 0.38 $ 0.38 $ 0.58 $ 0.81 Diluted $ 0.36 $ 0.37 $ 0.56 $ 0.79 2019 First Second Third Fourth (in thousands) Revenue $ 105,216 $ 111,183 $ 119,591 $ 128,673 Cost of revenue 55,374 60,096 60,512 67,999 Gross profit 49,842 51,087 59,079 60,674 Operating expenses: Research and development 30,953 28,976 28,649 40,122 Sales, general and administrative 15,787 29,899 20,457 14,438 Total operating expenses 46,740 58,875 49,106 54,560 Income (loss) from operations 3,102 (7,788) 9,973 6,114 Total other income, net 2,394 2,847 2,490 2,509 Income (loss) before benefit for income taxes 5,496 (4,941) 12,463 8,623 Benefit from income taxes (1,481) (2,916) (2,642) (4,159) Net income (loss) $ 6,977 $ (2,025) $ 15,105 $ 12,782 Net income (loss) per share: Basic $ 0.17 $ (0.05) $ 0.37 $ 0.31 Diluted $ 0.17 $ (0.05) $ 0.35 $ 0.30

SUBSEQUENT EVENTS

SUBSEQUENT EVENTS	12 Months Ended
	Dec. 31, 2020
Subsequent Events [Abstract]
Subsequent Events	SUBSEQUENT EVENTS Equity Awards The Company’s board of directors approved an increase in the number of shares authorized for issuance under the Company’s 2016 Equity Incentive Plan by 1,692,900 shares in accordance with the automatic annual increase provision of such plan, effective as of January 1, 2021. As a result of the Merger, all of the Company’s shares have been cancelled. In connection with the Company’s execution of the Amended and Restated Merger Agreement, the parties agreed that the 2018 PRSUs could be amended to provide that, for purposes of determining the Company’s total shareholder return (“TSR”) pursuant to the 2018 PRSU agreements, the “ending price” (as defined in the agreements) of the Company’s common stock would be determined based on the merger consideration of $115.00 per share. As a result, the compensation committee of the Company’s board of directors determined that the number of shares that were earned under the 2018 PRSUs based on the Company’s relative TSR calculated using the “ending price” of $115.00 was equal to 200% of the target number of shares subject to the awards. Accordingly, the 2018 PRSUs vested and were settled on January 15, 2021 and are no longer outstanding awards. This modification to the original award terms resulted in approximately $2.8 million of stock-compensation expense recognized in the first quarter of 2021. Pursuant to the 2019 PRSU agreements, any such PRSUs for which performance had been achieved as of immediately prior to the consummation of the Merger, which constituted a change in control thereunder, would vest, and any such PRSUs that did not so vest would be cancelled at such time for no consideration. On March 1, 2021, the compensation committee of the Company’s board of directors determined that the number of shares that vested and were earned under the 2019 PRSUs based on the Company’s relative TSR calculated using the “ending price” of $115.00 was equal to 148% of the target number of shares subject to the awards (the “Vested 2019 PRSUs”). Further, in light of the increased per share merger consideration from $70.00 to $115.00 in cash pursuant to the Amended and Restated Merger Agreement, the extended period of time between the execution of the Original Merger Agreement and the consummation of the Merger, in recognition of the Company’s performance during such period, and for purposes of additional retention the compensation committee of the Company’s board of directors determined to amend the 2019 PRSUs such that the number of 2019 PRSUs equal to the difference between 200% of the target number of 2019 PRSUs and the number of Vested 2019 PRSUs (the “Remaining 2019 PRSUs”) remained outstanding and subject to continued vesting, subject solely to the 2019 PRSU holder’s continued provision of service to the Company, Parent, or an affiliate thereof, on December 31, 2021 (which date is the end of the original 2019 PRSU performance period) or, upon an earlier termination of employment of the 2019 PRSU holder without “cause” by the Company, Parent, or any affiliate thereof, for “good reason” by the 2019 PRSU holder in accordance with the Severance Plan or, following the entry into an employment offer documents with Parent, at the end of the 2019 PRSU holder’s transition period of employment or service following the consummation of the Merger (in each case, as the terms “cause” and “good reason” are defined in the Severance Plan; provided, that, with respect to the Remaining 2019 PRSUs, clause (ii) of the definition of “good reason” under the Severance Plan, does not apply following the date a 2019 PRSU holder has accepted Parent’s offer of transitional or long-term employment, and shall otherwise be treated as unvested PRSUs for purposes of the Amended and Restated Merger Agreement. Accordingly, the Vested 2019 PRSUs were settled on March 1, 2021 and are no longer outstanding awards, the Remaining 2019 PRSUs were converted into the right to receive cash as described above. The amount of unrecognized compensation cost immediately prior to the consummation of the Merger related to the 2019 PRSUs was $1.8 million, which will be recognized in the first quarter of 2021. The Remaining 2019 PRSUs that were converted into the right to receive cash resulted in a modification to the original award terms and resulted in approximately $5.6 million of additional stock-compensation expense to be recognized in 2021. Tax Reserves The Company expects to release federal and state reserves for unrecognized tax benefits of between $3.0 million to $5.0 million in the first quarter of 2021 as a result of a favorable IRS audit settlement that occurred in that period. Litigation Related to the Original Merger Agreement On January 8, 2021, Parent commenced litigation against the Company in the Court of Chancery of the State of Delaware, or the Court of Chancery. The lawsuit, captioned Cisco Systems, Inc. v. Acacia Communications, Inc., Civil Action No. 2021-0018-JTL, sought, among other things, a temporary restraining order to enjoin the Company from terminating the Original Merger Agreement, a declaratory judgment that all necessary conditions to closing were satisfied and that the Company’s notice of termination of the Original Merger Agreement was invalid, and an order requiring the Company to specifically perform its obligations under the Original Merger Agreement and close the Merger as soon as practicable. Later on January 8, 2021, the Court of Chancery granted Parent’s motion for a temporary restraining order. In addition, the Court of Chancery granted Parent’s motion for expedited proceedings for consideration of Parent’s claims. Pursuant to the temporary restraining order, the Company continued to be bound by the terms of the Original Merger Agreement until further order of the Court of Chancery or as otherwise agreed by the parties. On January 11, 2021, the Company filed its answer and affirmative defenses in response to the complaint filed by Parent and simultaneously filed a counterclaim against Parent seeking a declaration that the Company validly terminated the Original Merger Agreement pursuant to the terms thereof. On January 14, 2021, in connection with the execution of the Amended and Restated Merger Agreement, the Company and Parent jointly requested that the Court of Chancery lift the temporary restraining order and dismiss with prejudice the litigation pending between the parties in that court. Later that same day, the Court of Chancery entered an order vacating the temporary restraining order and dismissing the parties’ respective claims with prejudice, with each party bearing its own costs. Closing of the Merger

BASIS OF PRESENTATION (Policies

BASIS OF PRESENTATION (Policies)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and include the accounts of Acacia Communications, Inc., and its Subsidiaries. All intercompany balances and transactions have been eliminated in consolidation.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenue and expenses during the reporting period. Actual results could differ from those estimates.
Comprehensive Income	Comprehensive Income Comprehensive income consists of two components, net income and other comprehensive income (loss). Other comprehensive income (loss) refers to income or losses that are recorded as an element of stockholders’ equity but are excluded from net income. The Company’s other comprehensive income (loss) consists of net unrealized gains and losses on available-for-sale securities, net of the related tax effect.
Revenue Recognition and Deferred Revenue and Cost of Revenue	Revenue Recognition and Deferred Revenue The Company generates all of its revenue from contracts with customers. The Company considers customer purchase orders, which in many cases are governed by master purchasing agreements, to be contracts with customers. The Company’s contracts with customers are generally for product only, and do not include other performance obligations such as services, extended warranties or other material rights. As part of its assessment of each contract, the Company evaluates certain factors including the customer’s ability to pay (or credit risk). For each contract, the Company considers the promise to transfer products, each of which is distinct, to be the identified performance obligations. In determining the transaction price, the price stated on the purchase order is typically fixed and represents the net consideration to which the Company expects to be entitled, and therefore there is no variable consideration. As the Company’s standard payment terms are less than one year, the Company has elected, as a practical expedient, to not assess whether a contract has a significant financing component. The Company allocates the transaction price to each distinct product based on its relative standalone selling price. The product price as specified on the purchase order is considered the standalone selling price as it is an observable source that depicts the price as if sold to a similar customer in similar circumstances. Revenue is recognized when control of the product is transferred to the customer (i.e., when the Company’s performance obligation is satisfied), which typically occurs upon shipment from the Company’s manufacturing site or delivery to the customer’s named location. In determining whether control has transferred, the Company considers if there is a present right to payment from the customer and when physical possession, legal title and risks and rewards of ownership have transferred to the customer. The Company also considered certain customer contracts that include acceptance clauses, but has concluded that delivery to the customer’s named location is the point at which the customer is able to direct the use of, and obtain substantially all of the remaining benefits from, the asset, and therefore the acceptance is considered a formality that does not impact the timing of revenue recognition. The Company generally provides an assurance warranty that its products will substantially conform to the agreed-upon specifications for 12 to 24 months from the date of shipment. The Company’s liability is limited to the cost of repair or replacement of the defective part. The Company does not consider activities related to such warranties to be a separate performance obligation. The terms and conditions of sale generally do not allow for refunds or product returns other than for warranty repairs. The Company has a limited number of customer contracts that provide for the performance of services or include multiple performance obligations. Once the Company determines the performance obligations, the Company determines the transaction price, which includes estimating the amount of variable consideration to be included in the transaction price, if any. The Company then allocates the transaction price to each performance obligation in the contract based on a relative stand-alone selling price method or using the variable consideration allocation exception if the required criteria are met. The corresponding revenues are recognized as the related performance obligations are satisfied. A receivable is recognized in the period the Company ships the product. Payment terms on invoiced amounts are based on contractual terms with each customer. In some cases, if control of the product has not yet transferred to the customer or the timing of the payments made by the customer precedes the Company’s fulfillment of the performance obligation, the Company recognizes a contract liability that is classified as “deferred revenue.” Deferred product costs represent products that have been billed to customers, for which the revenue associated with the arrangement has been deferred as a result of not meeting the revenue recognition criteria. The Company defers the product costs until recognition of the related revenue occurs. The Company has concluded that none of the costs it has incurred to obtain and fulfill its ASC 606 contracts meet the capitalization criteria, and as such, there are no costs deferred and recognized as assets on the consolidated balance sheet as of December 31, 2020 and 2019. Cost of Revenue The Company records all costs associated with its product sales in cost of revenue. These costs include the cost of materials, contract manufacturing fees, assembly, test, quality assurance, logistics-related fees and impacts of manufacturing yield. Cost of revenue also includes indirect costs such as warranty, excess and obsolete inventory charges, general overhead costs and depreciation.
Financial Instruments	Financial Instruments Cash equivalents include all highly liquid investments with an original maturity of three months or less upon acquisition. Cash equivalents may consist of bank deposit accounts, money market funds, U.S. treasury bonds, commercial paper, certificates of deposit, asset-backed securities and corporate debt securities. The Company’s marketable debt securities have been classified and accounted for as available-for-sale. Management determines the appropriate classification of its investments at the time of purchase and reevaluates the classifications at each balance sheet date. The Company classifies its investments in marketable debt securities as either short-term or long-term based on each instrument’s underlying contractual maturity date. The Company’s investments in marketable debt securities are carried at fair value, with unrealized gains and losses, net of taxes, reported as a component of accumulated other comprehensive income (loss) in stockholders’ equity, with the exception of unrealized losses believed to be other-than-temporary which are reported in earnings in the current period.
Concentrations of Credit Risk	Concentrations of Credit Risk Financial instruments that subject the Company to significant concentrations of credit risk consist primarily of cash and cash equivalents, marketable securities and accounts receivable. The majority of the Company’s cash and cash equivalents are at two financial institutions and the balances often exceed federally insured limits. Management believes that the financial institutions that hold the Company’s cash and cash equivalents are financially creditworthy and, accordingly, minimal credit risk exists with respect to those balances. Marketable securities consist of investments in U.S. treasury bonds, commercial paper, certificates of deposit, asset-backed securities and corporate debt securities. The main objective of the Company’s current investment policy is to preserve capital and maintain liquidity. The Company seeks to limit the amount of investments in any single issuer. As a result, the Company believes that, as of December 31, 2020 and 2019, its concentration of credit risk related to marketable securities was not significant.
Inventory	InventoryInventory, which consists of raw materials, work-in-process, and finished goods, is stated at the lower of cost or net realizable value, as determined on a specific cost basis and using the first-in, first-out convention. The Company reduces the carrying value of inventory to its estimated net realizable value for those items that are potentially excess, obsolete or slow moving based on changes in customer demand, technology developments or other economic factors. Such reductions in the carrying value of inventory are recorded within cost of revenue in the consolidated income statements. Any excess or obsolete inventory write-downs taken establish a new cost basis for the underlying inventory and cannot be reversed if there are subsequent increases in the Company’s demand forecast. If the Company is later able to sell such inventory, any related reserves would be reversed in the period of sale.
Property and Equipment	Property and Equipment Property and equipment are recorded at cost and depreciated using the straight-line method over the estimated useful lives of the related assets. The costs of additions and improvements are capitalized, while maintenance and repairs are charged to expense as incurred. The estimated useful lives of the Company’s property and equipment are as follows: Engineering laboratory equipment 3-7 years Computer software 1-3 years Computer equipment 3 years Furniture and fixtures 3-7 years Leasehold improvements Lesser of lease term or life of asset When assets are retired or otherwise disposed of, the assets and related accumulated depreciation are derecognized from the accounts and the resulting gain or loss is reflected in the consolidated income statements.
Leases	Leases The Company determines if an arrangement is a lease at inception. Operating leases are included in operating lease right-of-use (“ROU”) assets, accrued liabilities, and noncurrent operating lease liabilities in the Company’s consolidated balance sheets. ROU assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. Operating lease ROU assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. As most of the Company’s leases do not provide an implicit rate, the Company uses its incremental borrowing rate based on the estimated rate of interest for collateralized borrowing over a similar term of the lease payments at commencement date. The Company’s lease terms do not include options to extend or terminate leases unless the Company is reasonably certain that it will exercise those options. Lease expense for lease payments is recognized on a straight-line basis over the lease term. The Company has elected not to separate nonlease components from associated lease components for its real estate lease assets.
Impairment of Long-Lived Assets	Impairment of Long-Lived AssetsLong-lived assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the asset may not be recoverable. When such events occur, the Company compares the carrying amounts of the assets to their estimated undiscounted future cash flows. If this comparison indicates that there is an impairment, the amount of the impairment is calculated as the difference between the carrying value and the fair value.
Warranties	Warranties The Company’s standard warranty obligation to its customers provides for repair or replacement of a defective product at the Company’s discretion for a period of time following purchase, generally between 12 and 24 months. Factors that affect the warranty obligation include product failure rates, material usage and service delivery costs incurred in correcting product failures. In addition, from time to time, specific warranty accruals may be made if unforeseen technical problems arise. The
Commitments and Contingencies	Commitments and Contingencies In the normal course of business, the Company may become subject to loss contingencies, such as legal proceedings and claims arising out of its business. An accrual for a loss contingency is recognized when it is probable that an asset has been impaired or a liability has been incurred and the amount of the loss can be reasonably estimated. The Company expenses legal costs associated with loss contingencies as they are incurred.
Advertising Costs	Advertising CostsThe Company expenses advertising costs as incurred.
Research and Development Costs	Research and Development Costs The Company expenses all research and development costs as incurred. Research and development costs consist primarily of salary and benefit expenses, including stock-based compensation, for employees, costs for contractors engaged in research, design and development activities, costs incurred directly and with support from external vendors, such as outsourced development costs, as well as support costs for prototypes, depreciation, purchased intellectual property, facilities and travel.
Stock-based Compensation	Stock-Based Compensation The Company accounts for share-based payment awards granted to employees at fair value, which is measured using the fair value of the Company’s common stock on the grant date for time-vested restricted stock units (“RSUs”). Other input assumptions are used to determine the valuation of performance- or market-based RSU awards, as well as in the Black-Scholes option-pricing model for stock option awards and employee stock purchase rights. The measurement date for the fair value of employee awards is the date of grant. For all time-vested awards, stock-based compensation costs are recognized as expense on a ratable basis over the requisite service period, which is generally the vesting period. For awards with market and/or performance conditions, the Company recognizes stock-based compensation expense using the accelerated attribution method.
Foreign Currency Transactions	Foreign Currency TransactionsThe functional currency of the Company’s Subsidiaries is the U.S. dollar. All monetary assets and liabilities denominated in a foreign currency are revalued into U.S. dollars at the exchange rate on the consolidated balance sheet date. When transactions are required to be paid in the local currency of any Subsidiary, any resulting foreign currency transaction gain or loss is recorded as a component of other expense, net, in the consolidated income statements. To date, foreign currency transaction gain or loss associated with the Company’s Subsidiaries has not been significant.
Income Taxes	Income Taxes The Company recognizes deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the Company’s consolidated financial statements and tax returns. Deferred tax assets and liabilities are determined based upon the differences between the financial statement carrying amounts and the tax bases of existing assets and liabilities and for loss and credit carryforwards, using enacted tax rates expected to be in effect in the year in which the differences are expected to reverse. Deferred tax assets are reduced by a valuation allowance if it is not more likely than not that these assets will be realized. The Company accrues liabilities for potential payments of tax to various tax authorities related to uncertain tax positions. Liabilities are based on a determination of whether and how much of a tax benefit taken by the Company in its tax filings or positions is more likely than not to be realized following resolution of any potential uncertainties related to the tax benefit. Potential interest and penalties associated with such uncertain tax positions are recorded as a component of the provision for income taxes, if applicable. As of December 31, 2020 and 2019, the Company identified $7.9 million and $6.8 million of gross uncertain tax positions, respectively. Included in those balances as of December 31, 2020 and 2019 are $3.7 million and $3.6
Operating Segments	Operating Segments The Company operates as one operating segment. Operating segments are defined as components of an enterprise for which separate financial information is regularly evaluated by the chief operating decision maker (“CODM”), which is the Company’s chief executive officer, in deciding how to allocate resources and assess performance. The Company’s CODM evaluates the Company’s financial information for the purpose of allocating resources and assessing the performance of these resources on a consolidated basis.
Recently Adopted and Issued Accounting Pronouncements	Recently Adopted Accounting Pronouncements In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standard Update (“ASU”) 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”). ASU 2016-13 is intended to provide more decision-useful information about expected credit losses on financial instruments, including trade receivables, and other commitments to extend credit held by a reporting entity at each reporting date. The main provisions include presenting financial assets measured at amortized cost at the amount expected to be collected, which is net of an allowance for expected credit losses, and recording credit losses related to available-for-sale securities through an allowance for credit losses. On January 1, 2020, the Company adopted ASU 2016-13 using the modified retrospective approach. There was no impact from the adoption of ASU 2016-13 on the Company’s consolidated financial statements. The Company is exposed to credit losses through sales of its products. The Company determines if there is an expected loss on its accounts receivables using historical collection experience, current and future economic and market conditions and a review of the current status of customers' trade accounts receivables. The Company has recorded an immaterial amount of allowance for credit losses as of December 31, 2020 and December 31, 2019. Refer to Note 5 for information regarding how the Company assesses credit losses on its available-for-sale debt securities. Recently Issued Accounting Pronouncements In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes (“ASU 2019-12”). ASU 2019-12 is intended to simplify the accounting for income taxes by, among other things, removing certain exceptions related to the approach for intraperiod tax allocation, the methodology for calculating income taxes in an interim period when a year-to-date loss exceeds the anticipated loss for the year and the recognition of deferred tax

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Schedule of Estimated Useful Lives of Property and Equipment	The estimated useful lives of the Company’s property and equipment are as follows: Engineering laboratory equipment 3-7 years Computer software 1-3 years Computer equipment 3 years Furniture and fixtures 3-7 years Leasehold improvements Lesser of lease term or life of asset
Summary of Revenue by Geographic Region	Revenue by geographic country, based on ship-to destinations, which in certain instances may be the location of a contract manufacturer rather than the Company’s end customer, was as follows (in thousands): Year Ended December 31, 2020 2019 2018 United States $ 98,010 $ 70,702 $ 56,839 China 136,250 159,637 98,906 Germany 30,537 57,657 58,711 Thailand 191,219 82,413 68,217 Other 127,435 94,254 57,218 Total revenue $ 583,451 $ 464,663 $ 339,891
Summary of Total Long-Lived Assets by Geographic Region	Total long-lived assets by geographic country consisted of the following as of December 31, 2020 and 2019 (in thousands): December 31, 2020 2019 United States $ 19,458 $ 18,325 Thailand 5,036 3,870 China 1,475 1,949 Other 1,945 2,657 Total long-lived assets $ 27,914 $ 26,801

REVENUE (Tables)

REVENUE (Tables)	12 Months Ended
	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Schedule of Deferred Revenue and Accounts Receivable	The opening and closing balances of the Company’s accounts receivable and deferred revenue are as follows (in thousands): Balance at Beginning of Period (1/1/20) Increase / (Decrease) Balance at End of Period Year Ended December 31, 2020 Accounts receivable $ 97,948 $ 20,466 $ 118,414 Deferred revenue (current) $ 4,483 $ 1,271 $ 5,754 Deferred revenue (non-current) $ 3,444 $ (3,444) $ —
Schedule of Disaggregation of Revenue	The following table provides information about disaggregated revenue based on product group (in thousands). Further disaggregation of revenue by geographic country can be found in Note 3. Year Ended Year Ended Year Ended December 31, 2020 December 31, 2019 December 31, 2018 Revenue ($) Revenue (%) Revenue ($) Revenue (%) Revenue ($) Revenue (%) Embedded Modules $ 222,448 38 % $ 86,932 19 % $ 77,286 23 % Pluggable Modules 226,280 39 % 217,620 47 % 189,533 56 % Semiconductors 134,723 23 % 160,111 34 % 73,072 21 % Total revenue $ 583,451 100 % $ 464,663 100 % 339,891 100 %

FINANCIAL INSTRUMENTS (Tables)

FINANCIAL INSTRUMENTS (Tables)	12 Months Ended
	Dec. 31, 2020
Investments, Debt and Equity Securities [Abstract]
Schedule of Cash, Cash Equivalents and Short and Long-Term Marketable Securities	The following tables set forth the Company’s cash, cash equivalents and short- and long-term marketable securities as of December 31, 2020 and 2019 (in thousands): December 31, 2020 Amortized Cost Gross Unrealized Estimated Fair Value Cash and Cash Marketable Gains Losses (1) Cash $ 90,160 $ — $ — $ 90,160 $ 90,160 $ — Money market funds 7,451 — — 7,451 7,451 — U.S. treasury bonds 79,064 169 — 79,233 12,300 66,933 Commercial paper 82,261 5 (1) 82,265 7,997 74,268 Certificates of deposit 17,027 9 — 17,036 — 17,036 Asset-backed securities 60,475 98 (7) 60,566 — 60,566 Corporate debt securities 253,784 331 (65) 254,050 3,777 250,273 Total $ 590,222 $ 612 $ (73) $ 590,761 $ 121,685 $ 469,076 (1) Losses represent marketable securities that were in loss positions for less than one year. December 31, 2019 Amortized Cost Gross Unrealized Estimated Fair Value Cash and Cash Marketable Gains Losses (1) Cash $ 29,116 $ — $ — $ 29,116 $ 29,116 $ — Money market funds 2,010 — — 2,010 2,010 — U.S. treasury bonds 116,710 126 (1) 116,835 — 116,835 Commercial paper 44,300 — — 44,300 5,491 38,809 Certificates of deposit 24,522 19 (2) 24,539 — 24,539 Asset-backed securities 73,370 134 (5) 73,499 — 73,499 Corporate debt securities 180,607 475 (3) 181,079 — 181,079 Total $ 470,635 $ 754 $ (11) $ 471,378 $ 36,617 $ 434,761 (1) Losses represent marketable securities that were in loss positions for less than one year.
Schedule of Proceeds From Sales and Maturities of Marketable Securities	The proceeds from the sales and maturities of marketable securities, which were primarily reinvested and resulted in realized gains and losses, were as follows (in thousands): Year Ended December 31, 2020 2019 2018 Proceeds from the sales and maturities of marketable securities $ 383,667 $ 384,467 $ 340,920 Realized gains $ 125 $ 67 $ 18 Realized losses $ — $ (2) $ (109)
Schedule of Contractual Maturities of Short-Term and Long-Term Marketable Securities Held	The contractual maturities of short-term and long-term marketable securities held at December 31, 2020 and 2019 are as follows (in thousands): December 31, 2020 December 31, 2019 Amortized Cost Basis Aggregate Fair Value Amortized Cost Basis Aggregate Fair Value Due within one year $ 297,772 $ 298,185 $ 299,725 $ 300,129 Due after one year through four years 170,763 170,891 134,292 134,632 Total $ 468,535 $ 469,076 $ 434,017 $ 434,761

INVENTORY (Tables)

INVENTORY (Tables)	12 Months Ended
	Dec. 31, 2020
Inventory Disclosure [Abstract]
Schedule of Inventory	Inventory consisted of the following as of December 31, 2020 and 2019 (in thousands): December 31, 2020 2019 Raw materials $ 21,593 $ 24,777 Work-in-process 153 673 Finished goods 16,235 15,370 Inventory $ 37,981 $ 40,820

PROPERTY AND EQUIPMENT (Tables)

PROPERTY AND EQUIPMENT (Tables)	12 Months Ended
	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment	Property and equipment consisted of the following as of December 31, 2020 and 2019 (in thousands): December 31, 2020 2019 Engineering laboratory equipment $ 67,688 $ 58,320 Computer software 3,961 3,730 Computer equipment 9,483 7,837 Furniture and fixtures 3,641 3,641 Leasehold improvements 4,307 3,999 Construction in progress 2,912 2,449 Total property and equipment 91,992 79,976 Less: Accumulated depreciation (64,078) (53,175) Property and equipment, net $ 27,914 $ 26,801

ACCRUED LIABILITIES (Tables)

ACCRUED LIABILITIES (Tables)	12 Months Ended
	Dec. 31, 2020
Payables and Accruals [Abstract]
Schedule of Accrued Liabilities	Accrued liabilities consisted of the following as of December 31, 2020 and 2019 (in thousands): December 31, 2020 2019 Employee-related liabilities $ 8,598 $ 10,816 Current maturities of operating leases 4,411 4,228 Goods and services received not invoiced 4,251 2,297 Accrued manufacturing related expenses 1,218 3,781 Warranty reserve 9,530 10,354 Litigation and settlement accrual 28,000 20,000 Other accrued liabilities 6,220 10,204 Accrued liabilities $ 62,228 $ 61,680

LEASES (Tables)

LEASES (Tables)	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Schedule of Lessee, Operating Leases	The table below presents the lease-related assets and liabilities recorded on the consolidated balance sheet as of December 31, 2020 (in thousands): Classification on the Balance Sheet December 31, 2020 Assets Operating lease assets Operating lease right-of-use assets $ 28,483 Liabilities Current - operating Accrued liabilities 4,411 Noncurrent - operating Noncurrent operating lease liabilities 18,099 Total lease liabilities $ 22,510 Weighted-average remaining lease term - operating leases 6.0 years Weighted-average discount rate - operating leases(1) 4.21 % (1) Upon adoption of ASC 842, discount rates used for existing leases were established at January 1, 2019, which was the date of the Company’s initial adoption of ASC 842.
Schedule of Maturities of Operating Lease Liabilities	The table below reconciles the undiscounted cash flows for each of the first five years and total of the remaining years to the operating lease liabilities recorded on the consolidated balance sheet as of December 31, 2020 (in thousands): Operating Leases 2021 $ 4,518 2022 4,338 2023 4,493 2024 4,510 2025 2,373 Thereafter 4,619 Total minimum lease payments 24,851 Less: amount of lease payments representing interest (2,341) Present value of future minimum lease payments 22,510 Less: current obligation under leases 4,411 Long-term lease obligations $ 18,099

FAIR VALUE MEASUREMENT (Tables)

FAIR VALUE MEASUREMENT (Tables)	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Schedule of Assets Measured at Fair Value on Recurring Basis	The fair value of these assets measured on a recurring basis was determined using the following inputs as of December 31, 2020 and 2019 (in thousands): December 31, 2020 Quoted Significant Significant Total Fair Assets: Money market funds $ — $ 7,451 $ — $ 7,451 U.S. treasury bonds — 79,233 — 79,233 Commercial paper — 82,265 — 82,265 Certificates of deposit — 17,036 — 17,036 Asset-backed securities — 60,566 — 60,566 Corporate debt securities — 254,050 — 254,050 Total $ — $ 500,601 $ — $ 500,601 December 31, 2019 Quoted Significant Significant Total Fair Assets: Money market funds $ — $ 2,010 $ — $ 2,010 U.S. treasury bonds — 116,835 — 116,835 Commercial paper — 44,300 — 44,300 Certificates of deposit — 24,539 — 24,539 Asset-backed securities — 73,499 — 73,499 Corporate debt securities — 181,079 — 181,079 Total $ — $ 442,262 $ — $ 442,262

STOCK COMPENSATION PLANS (Table

STOCK COMPENSATION PLANS (Tables)	12 Months Ended
	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Schedule of Classification of Stock-Based Compensation	The following table summarizes the classification of stock-based compensation in the consolidated income statements for the years ended December 31, 2020, 2019 and 2018 (in thousands): Year Ended December 31, 2020 2019 2018 Cost of revenue $ 2,089 $ 2,047 $ 2,075 Research and development 21,499 21,383 17,564 Sales, general and administrative 10,075 11,723 9,975 Total stock-based compensation $ 33,663 $ 35,153 $ 29,614
Schedule of Stock-Based Compensation Expense by Award Type	The following table summarizes stock-based compensation expense by award type for the years ended December 31, 2020, 2019 and 2018 (in thousands): Year Ended December 31, 2020 2019 2018 Restricted stock units $ 32,585 $ 31,811 $ 25,864 Stock options 492 1,902 2,343 Employee stock purchase plan — 1,119 1,284 Other awards 586 321 123 Total stock-based compensation $ 33,663 $ 35,153 $ 29,614
Summary of Weighted-Average Assumptions Used to Estimate Fair Value of Options	The estimated grant-date fair value of the Company’s stock option awards issued to employees was calculated using the Black-Scholes option-pricing model. No stock options were granted in the years ended December 31, 2020 and 2019. During the year ended December 31, 2018, the assumptions used in the Black-Scholes model were as follows: Year Ended December 31, 2018 Risk-free interest rate 2.9% Expected dividend yield None Expected volatility 53.5% Expected term (in years) 6.3
Schedule of Stock Option Activities	A summary of stock option activity under the Company’s equity incentive plans for the year ended December 31, 2020 is as follows: Number of Weighted-Average Weighted-Average Aggregate Outstanding at December 31, 2019 715 $ 11.14 4.6 $ 41,036 Granted — $ — Exercised (161) $ 13.57 $ 8,889 Canceled — $ 13.38 Outstanding at December 31, 2020 554 $ 10.43 3.3 $ 35,116 Vested and expected to vest at: December 31, 2020 554 $ 10.43 3.3 $ 35,116 Exercisable at: December 31, 2020 551 $ 10.31 3.3 $ 34,950
Schedule of Weighted-Average Assumptions Used to Estimate Fair Value	The Company estimated the fair value of the 2019 PRSUs using a Monte Carlo valuation model on the date of grant, using the following assumptions: Risk-free interest rate 2.5% Expected dividend yield None Expected volatility 57.3% Expected term (in years) 2.9 Grant date fair value of underlying shares $44.43 Risk-free interest rate 2.3% Expected dividend yield None Expected volatility 51.4% Expected term (in years) 2.9 Grant date fair value of underlying shares $34.59 - $39.02
Summary of Changes in Company's RSU	A summary of the changes in the Company’s RSUs during the year ended December 31, 2020 is as follows: Restricted Shares Weighted-Average Outstanding at December 31, 2019 1,951 $ 48.69 Granted 204 $ 68.17 Vested (736) $ 44.05 Canceled (30) $ 51.12 Outstanding at December 31, 2020 1,389 $ 53.96
Schedule of Weighted-Average Assumptions Used to Estimate ESPP Fair Value	The fair value of the awards issued under the 2016 ESPP to employees was estimated at the beginning of the offering period using a Black-Scholes option-pricing model with the following assumptions: Year Ended December 31, 2019 2018 Risk-free interest rate 2.4% - 2.5% 1.3% - 2.1% Expected dividend yield None None Expected volatility 38.9% - 45.5% 48.6% - 66.4% Expected term (in years) 0.5 0.5

NET INCOME PER SHARE (Tables)

NET INCOME PER SHARE (Tables)	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Computation of Basic and Diluted Net Income Per Share Attributable to Common Stockholders	The following table sets forth the computation of the Company’s basic and diluted net income per share (in thousands, except per share amounts): Year Ended December 31, 2020 2019 2018 Numerator: Net income $ 90,391 $ 32,839 $ 4,916 Denominator: Weighted-average shares used to compute net income per share - basic 41,938 40,883 40,259 Dilutive effect of stock options, unvested restricted stock and restricted stock units, and employee stock purchase plan 1,295 1,671 1,738 Weighted-average shares used to compute net income per share - diluted 43,233 42,554 41,997 Net income per share Basic $ 2.16 $ 0.80 $ 0.12 Diluted $ 2.09 $ 0.77 $ 0.12
Summary of Common Stock Equivalents Excluded From Computation of Diluted Net Income Per Share	The following common stock equivalents (in thousands) were excluded from the computation of diluted net income per share for the periods presented because including them would have been antidilutive: Year Ended December 31, 2020 2019 2018 Options to purchase common stock 14 37 91 Unvested restricted stock units 1 86 336 Employee stock purchase plan — — 1

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Tables)	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Schedule of Changes in Warranty Reserve	Changes in the Company’s warranty liability, which is included as a component of accrued liabilities on the consolidated balance sheets, are set forth in the table below (in thousands): Year Ended December 31, 2020 2019 2018 Warranty reserve, beginning of period $ 10,354 $ 8,220 $ 8,306 Provisions made to warranty reserve during the period 7,689 13,708 11,775 Charges against warranty reserve during the period (8,513) (11,574) (11,861) Warranty reserve, end of period $ 9,530 $ 10,354 $ 8,220

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Schedule of Components of (Loss) Income Before Provision (Benefit) for Income Taxes	The components of income (loss) before provision (benefit) for income taxes are as follows (in thousands): Year Ended December 31, 2020 2019 2018 United States $ (30,213) $ (62,991) $ (35,832) Foreign 125,056 84,632 35,428 Total $ 94,843 $ 21,641 $ (404)
Schedule of Components of (Benefit) Provision for Income Taxes	The components of the provision (benefit) for income taxes are as follows (in thousands): Year Ended December 31, 2020 2019 2018 Current income tax (benefit) provision Federal $ (1,071) $ 135 $ (9,417) State (49) 252 23 Foreign 2,904 1,667 921 Total current income tax provision (benefit) $ 1,784 $ 2,054 $ (8,473) Deferred income tax provision (benefit) Federal 7,176 (7,114) 2,944 State (4,056) (5,427) 480 Foreign (452) (711) (271) Total deferred income tax provision (benefit) 2,668 (13,252) 3,153 Total income tax provision (benefit) $ 4,452 $ (11,198) $ (5,320)
Schedule of Components of Net Deferred Tax Assets	Significant components of the Company’s net deferred tax assets at December 31, 2020 and 2019, are as follows (in thousands): December 31, 2020 2019 Deferred tax assets: Accrued expenses $ 10,001 $ 8,748 Net operating loss carryforwards 9,406 16,624 Credit carryforwards 39,640 32,498 Lease liability 5,479 4,690 Stock-based compensation 3,112 4,200 Other 1,003 808 Total deferred tax assets $ 68,641 $ 67,568 Deferred tax liabilities: Depreciation (1,046) (161) Right-of-use asset (6,939) (5,930) Other (346) (758) Total deferred tax liabilities (8,331) (6,849) Valuation allowance (11,228) (8,921) Net deferred tax assets $ 49,082 $ 51,798
Summarizes Changes in Deferred Tax Asset Valuation Allowance	The table below summarizes changes in the deferred tax asset valuation allowance (in thousands): Year Ended December 31, Beginning Additions Reductions Ending 2018 $ 1,416 4,967 — $ 6,383 2019 $ 6,383 2,538 — $ 8,921 2020 $ 8,921 2,307 — $ 11,228
Schedule of Provision for Income Taxes Computed at Statutory Federal Income Tax Rate to (Benefit) Provision for Income Taxes	A reconciliation of the provision (benefit) for income taxes computed at the statutory federal income tax rate to the provision (benefit) for income taxes as reflected in the consolidated financial statements is as follows: Year Ended December 31, 2020 2019 2018 Provision for income taxes at statutory rate 21.0 % 21.0 % 21.0 % (Decreases) increases resulting from: Federal tax credits (8.1) (29.9) 1,304.6 Change in valuation allowance 2.4 11.7 (1,230.7) State tax expense, net of federal benefit (5.8) (36.4) 1,058.0 Meals and entertainment — 0.3 (24.0) Stock-based compensation expense (3.7) (26.8) 384.1 Change in uncertain tax positions 1.1 8.6 (116.5) Transition tax — — (9.6) APB23 state liability (0.4) (0.7) (2.0) Foreign rate differential (26.3) (77.3) 1,598.6 Foreign rate inclusion 25.1 84.0 (1,990.5) Other (0.6) (6.2) 323.8 Effective income tax rate 4.7 % (51.7) % 1,316.8 %
Summary of Changes in Gross Unrecognized Tax Benefits	The aggregate changes in gross unrecognized tax benefits during the years ended December 31, 2020 and 2019 were as follows (in thousands): Balance at December 31, 2018 $ 4,974 Increases for the tax positions taken during the year 1,857 Balance at December 31, 2019 $ 6,831 Increases for the tax positions taken during the year 1,209 Decreases for tax positions reduced during the year due to statute expirations, etc. (173) Balance at December 31, 2020 $ 7,867

CONCENTRATIONS OF RISK (Tables)

CONCENTRATIONS OF RISK (Tables)	12 Months Ended
	Dec. 31, 2020
Risks and Uncertainties [Abstract]
Summary of Concentrations of Risk	Customers with revenue equal to or greater than 10% of total revenue for the years ended December 31, 2020, 2019 and 2018 were as follows: Year Ended December 31, 2020 2019 2018 A 17 % 27 % 20 % B * 13 % 15 % C 18 % 17 % 17 % E 18 % 17 % 14 % H 13 % * * __________________________________________________________________________________________ * Less than 10% of revenue in the period indicated Customers, which include their authorized contract manufacturers, that accounted for equal to or greater than 10% of accounts receivable at December 31, 2020 and 2019 were as follows: December 31, 2020 December 31, 2019 A 23 % 28 % B * 16 % G * 10 % I 27 % * __________________________________________________________________________________________ * Less than 10% of accounts receivable at the date indicated Year Ended December 31, 2020 2019 2018 X 14 % 18 % 18 % Y 57 % 53 % 53 %

UNAUDITED QUARTERLY FINANCIAL_2

UNAUDITED QUARTERLY FINANCIAL INFORMATION (Tables)	12 Months Ended
	Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
Schedule of Unaudited Quarterly Financial Information	2020 First Second Third Fourth (in thousands) Revenue $ 125,626 $ 135,215 $ 158,456 $ 164,154 Cost of revenue 66,344 70,007 78,541 84,459 Gross profit 59,282 65,208 79,915 79,695 Operating expenses: Research and development 32,095 32,575 39,884 29,844 Sales, general and administrative 14,371 18,276 15,082 12,657 Total operating expenses 46,466 50,851 54,966 42,501 Income from operations 12,816 14,357 24,949 37,194 Total other income, net 2,250 1,591 995 691 Income before benefit for income taxes 15,066 15,948 25,944 37,885 (Benefit) provision for income taxes (578) (133) 1,655 3,508 Net income $ 15,644 $ 16,081 $ 24,289 $ 34,377 Net income per share: Basic $ 0.38 $ 0.38 $ 0.58 $ 0.81 Diluted $ 0.36 $ 0.37 $ 0.56 $ 0.79 2019 First Second Third Fourth (in thousands) Revenue $ 105,216 $ 111,183 $ 119,591 $ 128,673 Cost of revenue 55,374 60,096 60,512 67,999 Gross profit 49,842 51,087 59,079 60,674 Operating expenses: Research and development 30,953 28,976 28,649 40,122 Sales, general and administrative 15,787 29,899 20,457 14,438 Total operating expenses 46,740 58,875 49,106 54,560 Income (loss) from operations 3,102 (7,788) 9,973 6,114 Total other income, net 2,394 2,847 2,490 2,509 Income (loss) before benefit for income taxes 5,496 (4,941) 12,463 8,623 Benefit from income taxes (1,481) (2,916) (2,642) (4,159) Net income (loss) $ 6,977 $ (2,025) $ 15,105 $ 12,782 Net income (loss) per share: Basic $ 0.17 $ (0.05) $ 0.37 $ 0.31 Diluted $ 0.17 $ (0.05) $ 0.35 $ 0.30

NATURE OF THE BUSINESS AND OP_2

NATURE OF THE BUSINESS AND OPERATIONS (Details) $ / shares in Units, $ in Millions	Jan. 14, 2021$ / shares	Dec. 31, 2020USD ($)groupGB$ / shares	Dec. 31, 2019USD ($)$ / shares
Organization Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Number of product groups | group		3
Common stock, par value (in USD per share)		$ 0.0001	$ 0.0001
Subsequent event
Organization Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Business combination, conversion of stock (in USD per share)	$ 115
Common stock, par value (in USD per share)	$ 0.0001
Maximum
Organization Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Optical interconnect modules transmission speed | GB		1,200
Minimum
Organization Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Optical interconnect modules transmission speed | GB		100
Sales, general and administrative
Organization Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Business combination, acquisition related costs | $		$ 2.4	$ 7.6

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details)	12 Months Ended
	Dec. 31, 2020USD ($)segment	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Summary Of Significant Accounting Policies [Line Items]
Impairment of long-lived assets	$ 0	$ 300,000	$ 0
Advertising expenses	200,000	200,000
Foreign currency transaction (losses) gain	(200,000)	(200,000)	(400,000)
Gross uncertain tax positions	7,867,000	6,831,000	$ 4,974,000
Unrecognized tax benefits that, if recognized, would favorably impact effective tax rate	$ 3,700,000	$ 3,600,000
Number of operating segments | segment	1
Minimum
Summary Of Significant Accounting Policies [Line Items]
Standard warranty period on repair or replacement of defective products	12 months
Maximum
Summary Of Significant Accounting Policies [Line Items]
Standard warranty period on repair or replacement of defective products	24 months

SUMMARY OF SIGNIFICANT ACCOUN_4

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Summary of Estimated Useful Lives of Property and Equipment (Details)	12 Months Ended
	Dec. 31, 2020
Engineering laboratory equipment | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	3 years
Engineering laboratory equipment | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	7 years
Computer software | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	1 year
Computer software | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	3 years
Computer equipment
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	3 years
Furniture and fixtures | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	3 years
Furniture and fixtures | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	7 years

SUMMARY OF SIGNIFICANT ACCOUN_5

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Summary of Revenue by Geographic Region (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Total revenue	$ 164,154	$ 158,456	$ 135,215	$ 125,626	$ 128,673	$ 119,591	$ 111,183	$ 105,216	$ 583,451	$ 464,663	$ 339,891
United States
Segment Reporting Information [Line Items]
Total revenue									98,010	70,702	56,839
China
Segment Reporting Information [Line Items]
Total revenue									136,250	159,637	98,906
Germany
Segment Reporting Information [Line Items]
Total revenue									30,537	57,657	58,711
Thailand
Segment Reporting Information [Line Items]
Total revenue									191,219	82,413	68,217
Other
Segment Reporting Information [Line Items]
Total revenue									$ 127,435	$ 94,254	$ 57,218

SUMMARY OF SIGNIFICANT ACCOUN_6

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Summary of Total Long-Lived Assets by Geographic Region (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Total long-lived assets	$ 27,914	$ 26,801
United States
Segment Reporting Information [Line Items]
Total long-lived assets	19,458	18,325
Thailand
Segment Reporting Information [Line Items]
Total long-lived assets	5,036	3,870
China
Segment Reporting Information [Line Items]
Total long-lived assets	1,475	1,949
Other
Segment Reporting Information [Line Items]
Total long-lived assets	$ 1,945	$ 2,657

REVENUE - Deferred Revenue and

REVENUE - Deferred Revenue and Accounts Receivable (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Accounts receivable	$ 118,414	$ 97,948
Deferred revenue	5,754	4,483
Deferred revenue (non-current)	0	3,444
Increase (decrease) in accounts receivable	20,466	$ 7,117	$ 4,229
Increase (decrease) in deferred revenue (current)	1,271
Increase (decrease), in deferred revenue (non-current)	$ (3,444)

REVENUE REVENUE - Narrative (De

REVENUE REVENUE - Narrative (Details)	12 Months Ended
	Dec. 31, 2020USD ($)
Revenue from Contract with Customer [Abstract]
Deferred revenue	$ 3,800,000
Capitalized contracts	$ 0

REVENUE Disaggregation of Reven

REVENUE Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Revenue	$ 164,154	$ 158,456	$ 135,215	$ 125,626	$ 128,673	$ 119,591	$ 111,183	$ 105,216	$ 583,451	$ 464,663	$ 339,891
Revenue (%)									100.00%	100.00%	100.00%
Embedded Modules
Disaggregation of Revenue [Line Items]
Revenue									$ 222,448	$ 86,932	$ 77,286
Revenue (%)									38.00%	19.00%	23.00%
Pluggable Modules
Disaggregation of Revenue [Line Items]
Revenue									$ 226,280	$ 217,620	$ 189,533
Revenue (%)									39.00%	47.00%	56.00%
Semiconductors
Disaggregation of Revenue [Line Items]
Revenue									$ 134,723	$ 160,111	$ 73,072
Revenue (%)									23.00%	34.00%	21.00%

FINANCIAL INSTRUMENTS - Schedul

FINANCIAL INSTRUMENTS - Schedule of Cash, Cash Equivalents and Short- and Long-term Marketable Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Schedule Of Cash Cash Equivalents And Marketable Securities [Line Items]
Amortized Cost	$ 590,222	$ 470,635
Gross unrealized gains	612	754
Gross unrealized losses less than one year	(73)	(11)
Estimated Fair Value	590,761	471,378
Cash and Cash Equivalents	121,685	36,617
Marketable Securities	469,076	434,761
U.S. treasury bonds
Schedule Of Cash Cash Equivalents And Marketable Securities [Line Items]
Amortized Cost	79,064	116,710
Gross unrealized gains	169	126
Gross unrealized losses less than one year	0	(1)
Estimated Fair Value	79,233	116,835
Cash and Cash Equivalents	12,300	0
Marketable Securities	66,933	116,835
Commercial paper
Schedule Of Cash Cash Equivalents And Marketable Securities [Line Items]
Amortized Cost	82,261	44,300
Gross unrealized gains	5	0
Gross unrealized losses less than one year	(1)	0
Estimated Fair Value	82,265	44,300
Cash and Cash Equivalents	7,997	5,491
Marketable Securities	74,268	38,809
Certificates of deposit
Schedule Of Cash Cash Equivalents And Marketable Securities [Line Items]
Amortized Cost	17,027	24,522
Gross unrealized gains	9	19
Gross unrealized losses less than one year	0	(2)
Estimated Fair Value	17,036	24,539
Cash and Cash Equivalents	0	0
Marketable Securities	17,036	24,539
Asset-backed securities
Schedule Of Cash Cash Equivalents And Marketable Securities [Line Items]
Amortized Cost	60,475	73,370
Gross unrealized gains	98	134
Gross unrealized losses less than one year	(7)	(5)
Estimated Fair Value	60,566	73,499
Cash and Cash Equivalents	0	0
Marketable Securities	60,566	73,499
Corporate debt securities
Schedule Of Cash Cash Equivalents And Marketable Securities [Line Items]
Amortized Cost	253,784	180,607
Gross unrealized gains	331	475
Gross unrealized losses less than one year	(65)	(3)
Estimated Fair Value	254,050	181,079
Cash and Cash Equivalents	3,777	0
Marketable Securities	250,273	181,079
Cash
Schedule Of Cash Cash Equivalents And Marketable Securities [Line Items]
Amortized Cost	90,160	29,116
Estimated Fair Value	90,160	29,116
Cash and Cash Equivalents	90,160	29,116
Marketable Securities	0	0
Money market funds
Schedule Of Cash Cash Equivalents And Marketable Securities [Line Items]
Amortized Cost	7,451	2,010
Estimated Fair Value	7,451	2,010
Cash and Cash Equivalents	7,451	2,010
Marketable Securities	$ 0	$ 0

FINANCIAL INSTRUMENTS - Proceed

FINANCIAL INSTRUMENTS - Proceeds from Sales and Maturities of Marketable Securities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Proceeds from the sales and maturities of marketable securities	$ 383,667	$ 384,467	$ 340,920
Realized gains	125	67	18
Realized losses	$ 0	$ (2)	$ (109)

FINANCIAL INSTRUMENTS - Contrac

FINANCIAL INSTRUMENTS - Contractual Maturities of Short-term and Long-term Marketable Securities Held (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Due within one year, amortized cost basis	$ 297,772	$ 299,725
Due within one year, aggregate fair value	298,185	300,129
Due after one year through three years, amortized cost basis	170,763	134,292
Due after one year through three years, aggregate fair value	170,891	134,632
Amortized Cost Basis	468,535	434,017
Aggregate Fair Value	$ 469,076	$ 434,761

INVENTORY - Schedule of Invento

INVENTORY - Schedule of Inventory (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Inventory Disclosure [Abstract]
Raw materials	$ 21,593	$ 24,777
Work-in-process	153	673
Finished goods	16,235	15,370
Inventory	$ 37,981	$ 40,820

PROPERTY AND EQUIPMENT - Schedu

PROPERTY AND EQUIPMENT - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 91,992	$ 79,976
Less: Accumulated depreciation	(64,078)	(53,175)
Property and equipment, net	27,914	26,801
Engineering laboratory equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	67,688	58,320
Computer software
Property, Plant and Equipment [Line Items]
Total property and equipment	3,961	3,730
Computer equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	9,483	7,837
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Total property and equipment	3,641	3,641
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total property and equipment	4,307	3,999
Construction in progress
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 2,912	$ 2,449

PROPERTY AND EQUIPMENT - Narrat

PROPERTY AND EQUIPMENT - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Depreciation	$ 11,070	$ 12,559	$ 13,646

ACCRUED LIABILITIES - Schedule

ACCRUED LIABILITIES - Schedule of Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Payables and Accruals [Abstract]
Employee-related liabilities	$ 8,598	$ 10,816
Current maturities of operating leases	4,411	4,228
Goods and services received not invoiced	4,251	2,297
Accrued manufacturing related expenses	1,218	3,781
Warranty reserve	9,530	10,354	$ 8,220	$ 8,306
Litigation and settlement accrual	28,000	20,000
Other accrued liabilities	6,220	10,204
Accrued liabilities	$ 62,228	$ 61,680
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:AccruedLiabilitiesCurrent	us-gaap:AccruedLiabilitiesCurrent

LEASES - Narrative (Details)

LEASES - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Lessee, Lease, Description [Line Items]
Operating lease cost	$ 6	$ 5.6
Lease liabilities	$ 4.5	$ 5.3
Minimum
Lessee, Lease, Description [Line Items]
Remaining lease term (in years)	1 year
Renewal term (in years)	3 years
Maximum
Lessee, Lease, Description [Line Items]
Remaining lease term (in years)	8 years
Renewal term (in years)	5 years

LEASES - Balance Sheet Classifi

LEASES - Balance Sheet Classification of Lease Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating lease right-of-use assets	$ 28,483	$ 25,046
Current maturities of operating leases	4,411	4,228
Noncurrent operating lease liabilities	18,099	$ 15,726
Total lease liabilities	$ 22,510
Weighted-average remaining lease term - operating leases	6 years
Weighted-average discount rate - operating leases	4.21%

LEASES - Maturities of Operatin

LEASES - Maturities of Operating Leases Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Operating Leases, After Adoption of 842
2021	$ 4,518
2022	4,338
2023	4,493
2024	4,510
2025	2,373
Thereafter	4,619
Total minimum lease payments	24,851
Less: amount of lease payments representing interest	(2,341)
Total lease liabilities	22,510
Current maturities of operating leases	4,411	$ 4,228
Non-current operating lease liabilities	$ 18,099	$ 15,726

FAIR VALUE MEASUREMENT - Summar

FAIR VALUE MEASUREMENT - Summary of Assets Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	$ 469,076	$ 434,761
U.S. treasury bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	66,933	116,835
Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	74,268	38,809
Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	17,036	24,539
Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	60,566	73,499
Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	250,273	181,079
Recurring basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	500,601	442,262
Recurring basis | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	0	0
Recurring basis | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	500,601	442,262
Recurring basis | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	0	0
Recurring basis | U.S. treasury bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	79,233	116,835
Recurring basis | U.S. treasury bonds | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	0	0
Recurring basis | U.S. treasury bonds | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	79,233	116,835
Recurring basis | U.S. treasury bonds | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	0	0
Recurring basis | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	82,265	44,300
Recurring basis | Commercial paper | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	0	0
Recurring basis | Commercial paper | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	82,265	44,300
Recurring basis | Commercial paper | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	0	0
Recurring basis | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	17,036	24,539
Recurring basis | Certificates of deposit | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	0	0
Recurring basis | Certificates of deposit | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	17,036	24,539
Recurring basis | Certificates of deposit | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	0	0
Recurring basis | Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	60,566	73,499
Recurring basis | Asset-backed securities | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	0	0
Recurring basis | Asset-backed securities | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	60,566	73,499
Recurring basis | Asset-backed securities | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	0	0
Recurring basis | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	254,050	181,079
Recurring basis | Corporate debt securities | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	0	0
Recurring basis | Corporate debt securities | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	254,050	181,079
Recurring basis | Corporate debt securities | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	0	0
Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	0	0
Money market funds | Recurring basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	7,451	2,010
Money market funds | Recurring basis | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	0	0
Money market funds | Recurring basis | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	7,451	2,010
Money market funds | Recurring basis | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable Securities	$ 0	$ 0

FAIR VALUE MEASUREMENT - Narrat

FAIR VALUE MEASUREMENT - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Transfers between fair value measurement levels	$ 0	$ 0

STOCK COMPENSATION PLANS - Clas

STOCK COMPENSATION PLANS - Classification of Stock-based Compensation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation	$ 33,663	$ 35,153	$ 29,614
Cost of revenue
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation	2,089	2,047	2,075
Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation	21,499	21,383	17,564
Sales, general and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation	$ 10,075	$ 11,723	$ 9,975

STOCK COMPENSATION PLANS - Sche

STOCK COMPENSATION PLANS - Schedule of Stock-Based Compensation Expense by Award Type (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation	$ 33,663	$ 35,153	$ 29,614
Employee stock purchase plan
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation	0	1,119	1,284
Restricted stock units
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation	32,585	31,811	25,864
Stock options
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation	492	1,902	2,343
Other awards
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation	$ 586	$ 321	$ 123

STOCK COMPENSATION PLANS - Narr

STOCK COMPENSATION PLANS - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	May 12, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options granted (in shares)	0	0
Weighted average grant date fair value			$ 15.58
Intrinsic value of stock options exercised	$ 8,889,000
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, par value (in USD per share)	$ 0.0001	$ 0.0001
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options granted (in shares)	0	0
Total unrecognized compensation cost, stock options	$ 100,000	$ 500,000
Weighted average recognition period (in years)	1 year 3 months 18 days	7 months 6 days
Intrinsic value of stock options exercised	$ 8,900,000	$ 18,500,000	$ 15,900,000
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average recognition period (in years)	1 year 10 months 24 days	2 years 1 month 6 days
Restricted stock units granted (in shares)	204,000
Vested awards settled in cash	$ 0
Unrecognized stock-based compensation expense	$ 49,900,000	$ 70,100,000
Performance awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Right to receive number of common stock		1	1
Performance awards | Executive
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units granted (in shares)			94,854
Performance awards | Maximum | Executive
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units granted (in shares)		187,234
Earned performance awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards vesting period (in years)		3 years	3 years
Performance objective period		3 years	3 years
Vesting awards, amount		0	0
2009 Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual increase in ordinary shares for available for future issuance (in shares)				497,302,000
2009 Stock Plan | Tranche one | Vesting option one
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of shares vesting	20.00%
2009 Stock Plan | Tranche one | Vesting option two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of shares vesting	25.00%
2009 Stock Plan | Tranche two | Vesting option one
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards vesting period (in years)	4 years
2009 Stock Plan | Tranche two | Vesting option two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards vesting period (in years)	3 years
2009 Stock Plan | Stock options | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expiration period (in years)	10 years
2009 Stock Plan | Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expiration period (in years)	7 years
2016 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved, available for future issuance (in shares)	4,764,927
Annual shares increase for future issuance by percentage	4.00%
Common stock authorized for issuance (in shares)	11,228,533
2016 Equity Incentive Plan | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual increase in ordinary shares for available for future issuance (in shares)	3,600,000
2016 Equity Incentive Plan | Tranche one
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of shares vesting	25.00%
2016 Equity Incentive Plan | Tranche two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards vesting period (in years)	3 years
2016 Equity Incentive Plan | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock compensation expiration period (in years)	10 years
2016 ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of salary contribution by employees	15.00%
Discount on fair value for purchase of shares, percentage	85.00%

STOCK COMPENSATION PLANS - Weig

STOCK COMPENSATION PLANS - Weighted-Average Assumptions Used to Estimate Fair Value of Options (Details) - Stock options	12 Months Ended
	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	2.90%
Expected dividend yield	0.00%
Expected volatility	53.50%
Expected term (in years)	6 years 3 months 18 days

STOCK COMPENSATION PLANS - Stoc

STOCK COMPENSATION PLANS - Stock Option Activities (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Number of Options (in thousands)
Number of options outstanding at beginning of period (in shares)	715,000
Number of options granted (in shares)	0	0
Number of options exercised (in shares)	(161,000)
Number of options cancelled (in shares)	0
Number of options outstanding at end of period (in shares)	554,000	715,000
Number of options vested and expected to vest (in shares)	554,000
Number of options exercisable (in shares)	551,000
Weighted-Average Exercise Price
Weighted-average exercise price outstanding at beginning of period (in USD per share)	$ 11.14
Options exercised, Weighted-average exercise price (in USD per share)	0
Options exercised, Weighted-average exercise price (in USD per share)	13.57
Options cancelled, Weighted-average exercise price (in USD per share)	13.38
Weighted-average exercise price outstanding at end of period (in USD per share)	10.43	$ 11.14
Options vested and expected to vest, Weighted-average exercise price (in USD per share)	10.43
Options exercisable, Weighted-average exercise price (in USD per share)	$ 10.31
Weighted-Average Remaining Contractual Term (in years)
Options outstanding, Weighted-average remaining contractual term (in years)		4 years 7 months 6 days
Options vested and expected to vest, Weighted-average remaining contractual term (in years)	3 years 3 months 18 days
Options exercisable, Weighted-average remaining contractual term (in years)	3 years 3 months 18 days
Aggregate Intrinsic Value (in thousands)
Options outstanding, Aggregate intrinsic value at beginning of period	$ 41,036
Options exercised, Aggregate intrinsic value	8,889
Options outstanding, Aggregate intrinsic value at end of period	35,116	$ 41,036
Options vested and expected to vest, Aggregate intrinsic value	35,116
Options exercisable, Aggregate intrinsic value	$ 34,950

STOCK COMPENSATION PLANS - We_2

STOCK COMPENSATION PLANS - Weighted-Average Assumptions Used to Estimate Fair Value of RSUs and PRSUs (Details) - Performance awards - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	2.50%	2.30%
Expected dividend yield	0.00%	0.00%
Expected volatility	57.30%	51.40%
Expected term (in years)	2 years 10 months 24 days	2 years 10 months 24 days
Grant date fair value of underlying shares (in USD per share)	$ 44.43
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date fair value of underlying shares (in USD per share)		$ 34.59
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date fair value of underlying shares (in USD per share)		$ 39.02

STOCK COMPENSATION PLANS - Chan

STOCK COMPENSATION PLANS - Changes in Company Restricted Stock Units (Details) - Restricted stock units shares in Thousands	12 Months Ended
	Dec. 31, 2020$ / sharesshares
Restricted Shares (in thousands)
Shares outstanding, beginning balance (in shares) | shares	1,951
Granted (in shares) | shares	204
Vested (in shares) | shares	(736)
Canceled (in shares) | shares	(30)
Shares outstanding, ending balance (in shares) | shares	1,389
Weighted-Average Grant Date Fair Value
Shares outstanding, weighted-average grant date fair value, beginning balance (in USD per share) | $ / shares	$ 48.69
Granted, weighted-average grant date fair value (in USD per share) | $ / shares	68.17
Vested, weighted-average grant date fair value (in USD per share) | $ / shares	44.05
Canceled, weighted-average grant date fair value (in USD per share) | $ / shares	51.12
Shares outstanding, weighted-average grant date fair value, ending balance (in USD per share) | $ / shares	$ 53.96

STOCK COMPENSATION PLANS - We_3

STOCK COMPENSATION PLANS - Weighted-Average Assumptions Used to Estimate Fair Value of ESPP (Details) (Details) - 2016 ESPP	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate, minimum	2.40%	1.30%
Risk-free interest rate, maximum	2.50%	2.10%
Expected dividend yield	0.00%	0.00%
Expected volatility, minimum	38.90%	48.60%
Expected volatility, maximum	45.50%	66.40%
Expected term (in years)	6 months	6 months

NET INCOME PER SHARE - Computat

NET INCOME PER SHARE - Computation of Basic and Diluted Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Numerator:
Net income	$ 34,377	$ 24,289	$ 16,081	$ 15,644	$ 12,782	$ 15,105	$ (2,025)	$ 6,977	$ 90,391	$ 32,839	$ 4,916
Weighted-average shares used to compute earnings per share:
Weighted-average shares used to compute net income per share attributable to common stockholders - basic (in shares)									41,938	40,883	40,259
Dilutive effect of stock options, unvested restricted stock and restricted stock units, preferred stock warrants, and employee stock purchase plan (in shares)									1,295	1,671	1,738
Weighted-average shares used to compute net income per share attributable to common stockholders - diluted (in shares)									43,233	42,554	41,997
Net income per share
Basic (in USD per share)	$ 0.81	$ 0.58	$ 0.38	$ 0.38	$ 0.31	$ 0.37	$ (0.05)	$ 0.17	$ 2.16	$ 0.80	$ 0.12
Diluted (in USD per share)	$ 0.79	$ 0.56	$ 0.37	$ 0.36	$ 0.30	$ 0.35	$ (0.05)	$ 0.17	$ 2.09	$ 0.77	$ 0.12

NET INCOME PER SHARE - Summary

NET INCOME PER SHARE - Summary of Common Stock Equivalents Excluded from Computation of Diluted Net Income Per Share (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares excluded from computation of earnings per share (in shares)	14	37	91
Unvested restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares excluded from computation of earnings per share (in shares)	1	86	336
Employee stock purchase plan
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares excluded from computation of earnings per share (in shares)	0	0	1

COMMITMENTS AND CONTINGENCIES -

COMMITMENTS AND CONTINGENCIES - Narrative (Details)	Jan. 17, 2020USD ($)	Jul. 18, 2019USD ($)	Jul. 17, 2019USD ($)	Aug. 31, 2018	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 20, 2019USD ($)
Loss Contingencies [Line Items]
Litigation and settlement accrual					$ 28,000,000	$ 20,000,000
Employee severance
Loss Contingencies [Line Items]
Maximum period for employer contributions to cost of health care continuation under Consolidated Omnibus Budget Reconciliation Act that executive is entitled to upon termination				12 months
Percentage of annual base salary that executive is entitled to upon termination				1
Percentage of target annual bonus that executive is entitled to upon termination for the year in which it occurs				1
Employee severance | Chief executive officer
Loss Contingencies [Line Items]
Period to continue receiving base salary that executive is entitled to upon termination				12 months
Employee severance | Other participants
Loss Contingencies [Line Items]
Period to continue receiving base salary that executive is entitled to upon termination				9 months
Minimum
Loss Contingencies [Line Items]
Standard warranty period on repair or replacement of defective products					12 months
Maximum
Loss Contingencies [Line Items]
Standard warranty period on repair or replacement of defective products					24 months
Indemnification agreement
Loss Contingencies [Line Items]
Litigation and settlement accrual					$ 0	$ 0
Pending litigation | ViaSat, Inc. U.S. District Court for the Southern District of California
Loss Contingencies [Line Items]
Supersedeas bond, amount							$ 75,000,000
Pending litigation | ViaSat, Inc. U.S. District Court for the Southern District of California | Breach of contract
Loss Contingencies [Line Items]
Litigation settlement, amount awarded to other party	$ 100,000	$ 12,800,000	$ 49,300,000
Litigation settlement, post trail expense, cost-of-proof sanctions		6,200,000
Pending litigation | ViaSat, Inc. U.S. District Court for the Southern District of California | Breach of contract | Maximum
Loss Contingencies [Line Items]
Litigation settlement, post trial expense		$ 10,000,000
Pending litigation | ViaSat, Inc. U.S. District Court for the Southern District of California | Trade secret misappropriation
Loss Contingencies [Line Items]
Litigation settlement, amount awarded to other party			1
Litigation settlement, amount awarded from other party			$ 1
Pending litigation | ViaSat, Inc. Commonwealth of Massachusetts
Loss Contingencies [Line Items]
Litigation and settlement accrual					$ 28,000,000

COMMITMENTS AND CONTINGENCIES_2

COMMITMENTS AND CONTINGENCIES - Warranty Reserve (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Movement in Standard Product Warranty Accrual [Roll Forward]
Warranty reserve, beginning of period	$ 10,354	$ 8,220	$ 8,306
Provisions made to warranty reserve during the period	7,689	13,708	11,775
Charges against warranty reserve during the period	(8,513)	(11,574)	(11,861)
Warranty reserve, end of period	$ 9,530	$ 10,354	$ 8,220

INCOME TAXES - Components of (L

INCOME TAXES - Components of (Loss) Income before Provision (Benefit) for Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
United States									$ (30,213)	$ (62,991)	$ (35,832)
Foreign									125,056	84,632	35,428
Income (loss) before provision (benefit) for income taxes	$ 37,885	$ 25,944	$ 15,948	$ 15,066	$ 8,623	$ 12,463	$ (4,941)	$ 5,496	$ 94,843	$ 21,641	$ (404)

INCOME TAXES - Components of Pr

INCOME TAXES - Components of Provision (Benefit) for Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current income tax (benefit) provision
Federal									$ (1,071)	$ 135	$ (9,417)
State									(49)	252	23
Foreign									2,904	1,667	921
Total current income tax provision (benefit)									1,784	2,054	(8,473)
Deferred income tax provision (benefit)
Federal									7,176	(7,114)	2,944
State									(4,056)	(5,427)	480
Foreign									(452)	(711)	(271)
Total deferred income tax provision (benefit)									2,668	(13,252)	3,153
Total income tax provision (benefit)	$ 3,508	$ 1,655	$ (133)	$ (578)	$ (4,159)	$ (2,642)	$ (2,916)	$ (1,481)	$ 4,452	$ (11,198)	$ (5,320)

INCOME TAXES - Narrative (Detai

INCOME TAXES - Narrative (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Mar. 01, 2021
Income Taxes [Line Items]
Cumulative foreign earnings where no US income tax was provided	$ 17,300,000								$ 17,300,000
Duration taken into consideration to calculate cumulative profitability (in years)									3 years
Cumulative profitability	116,100,000								$ 116,100,000
Net deferred tax assets	49,082,000				$ 51,798,000				49,082,000	$ 51,798,000
Partial valuation allowance maintained against U.S deferred tax assets	11,228,000				8,921,000				11,228,000	8,921,000
Income tax expense (benefit)	3,508,000	$ 1,655,000	$ (133,000)	$ (578,000)	(4,159,000)	$ (2,642,000)	$ (2,916,000)	$ (1,481,000)	$ 4,452,000	$ (11,198,000)	$ (5,320,000)
Effective income tax rate (in percent)									4.70%	(51.70%)	1316.80%
Net operating losses utilization limit, year 2017	4,800,000								$ 4,800,000
Net operating losses utilization limit, year 2018	2,300,000								2,300,000
Net operating losses utilization limit, thereafter	1,400,000								1,400,000
Uncertain tax positions	7,867,000				6,831,000				7,867,000	$ 6,831,000	$ 4,974,000
Unrecognized tax benefits that, if recognized, would favorably impact effective tax rate	3,700,000				$ 3,600,000				3,700,000	$ 3,600,000
Interest or penalties recognized									0
Interest or penalties accrued	0								0
Federal
Income Taxes [Line Items]
Net operating loss carryforwards	1,300,000								1,300,000
Expiration of federal net operating loss carryforwards before utilization	800,000								800,000
Estimate of possible loss									6,300,000
Federal | Research and development and other tax credit carryforward
Income Taxes [Line Items]
Research and development and other credit carryforwards	21,000,000								21,000,000
State
Income Taxes [Line Items]
Net operating loss carryforwards	140,200,000								140,200,000
State | Research and development and other tax credit carryforward
Income Taxes [Line Items]
Research and development and other credit carryforwards	27,100,000								27,100,000
Foreign | Research and development and other tax credit carryforward
Income Taxes [Line Items]
Research and development and other credit carryforwards	$ 1,900,000								$ 1,900,000
Federal and state | Subsequent event | Minimum
Income Taxes [Line Items]
Uncertain tax positions												$ 3,000,000
Federal and state | Subsequent event | Maximum
Income Taxes [Line Items]
Uncertain tax positions												$ 5,000,000

INCOME TAXES - Net Deferred Tax

INCOME TAXES - Net Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Accrued expenses	$ 10,001	$ 8,748
Net operating loss carryforwards	9,406	16,624
Credit carryforwards	39,640	32,498
Lease liability	5,479	4,690
Stock-based compensation	3,112	4,200
Other	1,003	808
Total deferred tax assets	68,641	67,568
Deferred tax liabilities:
Depreciation	(1,046)	(161)
Right-of-use asset	(6,939)	(5,930)
Other	(346)	(758)
Total deferred tax liabilities	(8,331)	(6,849)
Valuation allowance	(11,228)	(8,921)
Net deferred tax assets	$ 49,082	$ 51,798

INCOME TAXES - Summary of Chang

INCOME TAXES - Summary of Changes in Deferred Tax Asset Valuation Allowance (Details) - Valuation allowance of deferred tax assets - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning Balance	$ 8,921	$ 6,383	$ 1,416
Additions	2,307	2,538	4,967
Reductions	0	0	0
Ending Balance	$ 11,228	$ 8,921	$ 6,383

INCOME TAXES - Provision for In

INCOME TAXES - Provision for Income Taxes Computed at Statutory Federal Income Tax Rate to (Benefit) Provision for Income Taxes (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Provision for income taxes at statutory rate	21.00%	21.00%	21.00%
(Decreases) increases resulting from:
Federal tax credits	(8.10%)	(29.90%)	1304.60%
Change in valuation allowance	2.40%	11.70%	(1230.70%)
State tax expense, net of federal benefit	(5.80%)	(36.40%)	1058.00%
Meals and entertainment	0.00%	0.30%	(24.00%)
Stock-based compensation expense	(3.70%)	(26.80%)	384.10%
Change in uncertain tax positions	1.10%	8.60%	(116.50%)
Transition tax	0	0	(0.096)
APB23 state liability	(0.40%)	(0.70%)	(2.00%)
Foreign rate differential	(26.30%)	(77.30%)	1598.60%
Foreign rate inclusion	25.10%	84.00%	(1990.50%)
Other	(0.60%)	(6.20%)	323.80%
Effective income tax rate	4.70%	(51.70%)	1316.80%

INCOME TAXES - Changes in Gross

INCOME TAXES - Changes in Gross Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Balance at beginning of year	$ 6,831	$ 4,974
Increases for the tax positions taken during the year	1,209	1,857
Decreases for tax positions reduced during the year due to statute expirations, etc.	(173)
Balance at end of year	$ 7,867	$ 6,831

CONCENTRATIONS OF RISK - Summar

CONCENTRATIONS OF RISK - Summary of Customer Concentration of Total Revenue (Details) - Customer concentration risk - Revenue	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Customer A
Concentration Risk [Line Items]
Concentration risk, percentage	17.00%	27.00%	20.00%
Customer B
Concentration Risk [Line Items]
Concentration risk, percentage		13.00%	15.00%
Customer C
Concentration Risk [Line Items]
Concentration risk, percentage	18.00%	17.00%	17.00%
Customer E
Concentration Risk [Line Items]
Concentration risk, percentage	18.00%	17.00%	14.00%
Customer H
Concentration Risk [Line Items]
Concentration risk, percentage	13.00%

CONCENTRATIONS OF RISK - Summ_2

CONCENTRATIONS OF RISK - Summary of Customer Concentration of Accounts Receivable (Details) - Customer concentration risk - Accounts receivable	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Customer A
Concentration Risk [Line Items]
Concentration risk, percentage	23.00%	28.00%
Customer B
Concentration Risk [Line Items]
Concentration risk, percentage		16.00%
Customer G
Concentration Risk [Line Items]
Concentration risk, percentage		10.00%
Customer I
Concentration Risk [Line Items]
Concentration risk, percentage	27.00%

CONCENTRATIONS OF RISK - Summ_3

CONCENTRATIONS OF RISK - Summary of Supplier Concentration (Details) - Supplier concentration risk - Purchases	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Supplier X
Concentration Risk [Line Items]
Concentration risk, percentage	14.00%	18.00%	18.00%
Supplier Y
Concentration Risk [Line Items]
Concentration risk, percentage	57.00%	53.00%	53.00%

RETIREMENT PLAN - Narrative (De

RETIREMENT PLAN - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Retirement Benefits [Abstract]
Total matching contributions to 401 (k) Plan	$ 2.2	$ 1.9	$ 1.6

RELATED PARTIES - Narrative (De

RELATED PARTIES - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
ADI
Related Party Transaction [Line Items]
Purchase from related party	$ 8.5	$ 4.1	$ 3.8
Development agreement			1.5
Development arrangement expense	0.5	0.3	0.8
M/A-COM
Related Party Transaction [Line Items]
Purchase from related party	$ 0	$ 0	$ 0.3

UNAUDITED QUARTERLY FINANCIAL_3

UNAUDITED QUARTERLY FINANCIAL INFORMATION (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 164,154	$ 158,456	$ 135,215	$ 125,626	$ 128,673	$ 119,591	$ 111,183	$ 105,216	$ 583,451	$ 464,663	$ 339,891
Cost of revenue	84,459	78,541	70,007	66,344	67,999	60,512	60,096	55,374	299,351	243,981	192,771
Gross profit	79,695	79,915	65,208	59,282	60,674	59,079	51,087	49,842	284,100	220,682	147,120
Operating expenses:
Research and development	29,844	39,884	32,575	32,095	40,122	28,649	28,976	30,953	134,398	128,700	102,406
Sales, general and administrative	12,657	15,082	18,276	14,371	14,438	20,457	29,899	15,787	60,386	80,581	51,864
Total operating expenses	42,501	54,966	50,851	46,466	54,560	49,106	58,875	46,740	194,784	209,281	154,270
Income (loss) from operations	37,194	24,949	14,357	12,816	6,114	9,973	(7,788)	3,102	89,316	11,401	(7,150)
Total other income, net	691	995	1,591	2,250	2,509	2,490	2,847	2,394	5,527	10,240	6,746
Income (loss) before provision (benefit) for income taxes	37,885	25,944	15,948	15,066	8,623	12,463	(4,941)	5,496	94,843	21,641	(404)
(Benefit) provision for income taxes	3,508	1,655	(133)	(578)	(4,159)	(2,642)	(2,916)	(1,481)	4,452	(11,198)	(5,320)
Net income	$ 34,377	$ 24,289	$ 16,081	$ 15,644	$ 12,782	$ 15,105	$ (2,025)	$ 6,977	$ 90,391	$ 32,839	$ 4,916
Net income per share:
Basic (in USD per share)	$ 0.81	$ 0.58	$ 0.38	$ 0.38	$ 0.31	$ 0.37	$ (0.05)	$ 0.17	$ 2.16	$ 0.80	$ 0.12
Diluted (in USD per share)	$ 0.79	$ 0.56	$ 0.37	$ 0.36	$ 0.30	$ 0.35	$ (0.05)	$ 0.17	$ 2.09	$ 0.77	$ 0.12

SUBSEQUENT EVENTS - Narrative (

SUBSEQUENT EVENTS - Narrative (Details) $ / shares in Units, $ in Thousands	Mar. 01, 2021USD ($)	Jan. 15, 2021$ / shares	Jan. 14, 2021USD ($)$ / shares	Jan. 01, 2021shares	Jul. 18, 2019	Jul. 08, 2019$ / shares	Mar. 01, 2021USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Jan. 13, 2021USD ($)
Subsequent Event [Line Items]
Target number of shares subject to sward, in percent					2
Stock-based compensation expense								$ 33,077	$ 34,832	$ 29,510
Uncertain tax positions								$ 7,867	$ 6,831	$ 4,974
2019 PRSU agreement | Earned performance awards
Subsequent Event [Line Items]
Business combination, conversion of stock (in USD per share) | $ / shares						$ 70
Subsequent event
Subsequent Event [Line Items]
Business combination, conversion of stock (in USD per share) | $ / shares			$ 115
Stock-based compensation expense							$ 2,800
Subsequent event | Federal and state | Minimum
Subsequent Event [Line Items]
Uncertain tax positions	$ 3,000						3,000
Subsequent event | Federal and state | Maximum
Subsequent Event [Line Items]
Uncertain tax positions	$ 5,000						$ 5,000
Subsequent event | 2016 Equity Incentive Plan
Subsequent Event [Line Items]
Annual increase of shares for future issuance | shares				1,692,900
Subsequent event | 2018 PRSU agreement | Earned performance awards
Subsequent Event [Line Items]
Business combination, conversion of stock (in USD per share) | $ / shares		$ 115	115
Subsequent event | 2019 PRSU agreement | Earned performance awards
Subsequent Event [Line Items]
Business combination, conversion of stock (in USD per share) | $ / shares			$ 115
Target number of shares subject to sward, in percent	1.48
Unrecognized stock-based compensation expense			$ 5,600								$ 1,800