Acacia Communications (ACIA) 10-Q 3 Aug 17 2017 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2017	Jul. 28, 2017
Document And Entity Information [Abstract]
Entity Registrant Name	Acacia Communications, Inc.
Trading Symbol	ACIA
Entity Central Index Key	1,651,235
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Document Type	10-Q
Document Period End Date	Jun. 30, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q2
Amendment Flag	false
Entity Common Stock, Shares Outstanding		39,228,125

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 106,127	$ 206,402
Marketable securities - short-term	176,293	104,004
Accounts receivable	82,911	108,127
Inventory	41,686	31,681
Prepaid expenses and other current assets	18,750	12,076
Deferred product costs	371	85
Total current assets	426,138	462,375
Marketable securities - long-term	60,486	0
Restricted cash	37	1,630
Property and equipment, net	25,765	25,124
Deferred tax asset	37,472	23,533
Other assets	8,864	4,274
Total assets	558,762	516,936
Current liabilities:
Accounts payable	35,224	49,430
Accrued liabilities	31,098	29,863
Deferred revenue	1,530	1,375
Total current liabilities	67,852	80,668
Other long-term liabilities	1,932	1,473
Total liabilities	69,784	82,141
Commitments and contingencies (Note 10)
Stockholders' equity:
Preferred stock, $0.0001 par value; 5,000 shares authorized; none issued and outstanding at June 30, 2017 and December 31, 2016	0	0
Common stock, $0.0001 par value; 150,000 shares authorized; 39,059 and 37,998 shares issued and outstanding at June 30, 2017 and December 31, 2016, respectively	4	4
Additional paid-in capital	309,717	295,893
Accumulated other comprehensive loss	(30)	(16)
Retained earnings	179,287	138,914
Total stockholders' equity	488,978	434,795
Total liabilities and stockholders' equity	$ 558,762	$ 516,936

CONDENSED CONSOLIDATED BALANCE3

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Jun. 30, 2017	Dec. 31, 2016
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)	39,059,000	37,998,000
Common stock, shares outstanding (in shares)	39,059,000	37,998,000

CONDENSED CONSOLIDATED INCOME S

CONDENSED CONSOLIDATED INCOME STATEMENTS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Income Statement [Abstract]
Revenue	$ 78,898	$ 116,192	$ 193,565	$ 200,681
Cost of revenue	53,516	62,240	111,883	111,323
Gross profit	25,382	53,952	81,682	89,358
Operating expenses:
Research and development	22,734	21,839	40,462	37,253
Sales, general and administrative	9,368	8,649	18,059	12,703
Gain on disposal of property and equipment	(47)	0	(47)	0
Total operating expenses	32,055	30,488	58,474	49,956
(Loss) income from operations	(6,673)	23,464	23,208	39,402
Other income (expense), net:
Interest income, net	827	20	1,272	28
Change in fair value of preferred stock warrant liability	0	(3,609)	0	(3,361)
Other expense	(1)	(58)	(39)	(78)
Total other income (expense), net	826	(3,647)	1,233	(3,411)
(Loss) income before (benefit) provision for income taxes	(5,847)	19,817	24,441	35,991
(Benefit) provision for income taxes	(10,511)	2,219	(15,932)	3,796
Net income	4,664	17,598	40,373	32,195
Accretion of redeemable convertible preferred stock	0	(636)	0	(1,722)
Undistributed earnings attributable to participating securities	0	(6,455)	0	(17,467)
Net income attributable to common stockholders - basic	4,664	10,507	40,373	13,006
Net income attributable to common stockholders - diluted	$ 4,664	$ 10,507	$ 40,373	$ 13,006
Net income per share attributable to common stockholders:
Basic (in USD per share)	$ 0.12	$ 0.51	$ 1.05	$ 0.95
Diluted (in USD per share)	$ 0.11	$ 0.43	$ 0.97	$ 0.77
Weighted-average shares used to compute net income per share attributable to common stockholders:
Basic (in shares)	38,756	20,760	38,546	13,751
Diluted (in shares)	41,582	24,373	41,639	16,927

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 4,664	$ 17,598	$ 40,373	$ 32,195
Other comprehensive income (loss):
Changes in unrealized gain (loss) on marketable securities, net of income taxes of $13 and $(2) for the three and six months ended June 30, 2017, respectively	22	0	(14)	0
Comprehensive income	$ 4,686	$ 17,598	$ 40,359	$ 32,195

CONDENSED CONSOLIDATED STATEME6

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax	$ 13	$ (2)

CONDENSED CONSOLIDATED STATEME7

CONDENSED CONSOLIDATED STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Retained Earnings	Redeemable Convertible Preferred Stock
Temporary equity, beginning balance (in shares) at Dec. 31, 2015						24,177
Temporary equity, beginning balance at Dec. 31, 2015						$ 70,780
Beginning balance (in shares) at Dec. 31, 2015		6,669
Beginning balance at Dec. 31, 2015	$ 8,016	$ 1	$ 0	$ 0	$ 8,015
Temporary equity, accretion of preferred stock issuance costs						94
Accretion of preferred stock issuance costs	(94)		(94)
Temporary equity, accretion to redemption value						$ 1,628
Accretion to redemption value	(1,628)		(950)		(678)
Temporary equity, conversion of redeemable convertible preferred stock into common stock upon initial public offering (in shares)						(24,177)
Temporary equity, conversion of redeemable convertible preferred stock into common stock upon initial public offering						$ (72,502)
Conversion of redeemable convertible preferred stock into common stock upon initial public offering (in shares)		24,177
Conversion of redeemable convertible preferred stock into common stock upon initial public offering	72,502	$ 2	72,500
Reclassification of preferred stock warrant liability into additional paid-in capital upon conversion to common stock warrants	6,615		6,615
Issuance of common stock in relation to initial public offering, net of offering costs incurred of $3,824 (in shares)		4,570
Issuance of common stock in relation to initial public offering, net of offering costs incurred of $3,824	93,933	$ 1	93,932
Vesting of restricted common stock (in shares)		43
Exercise of common stock options (in shares)		200
Exercise of common stock options	283		283
Stock-based compensation expense	9,461		9,461
Unrealized losses on marketable securities, net of tax of $(2)	0
Net income	32,195				32,195
Temporary equity, ending balance (in shares) at Jun. 30, 2016						0
Temporary equity, ending balance at Jun. 30, 2016						$ 0
Ending balance (in shares) at Jun. 30, 2016		35,659
Ending balance at Jun. 30, 2016	221,283	$ 4	181,747	0	39,532
Temporary equity, beginning balance (in shares) at Dec. 31, 2016						0
Temporary equity, beginning balance at Dec. 31, 2016						$ 0
Beginning balance (in shares) at Dec. 31, 2016		37,998
Beginning balance at Dec. 31, 2016	$ 434,795	$ 4	295,893	(16)	138,914
Vesting of restricted common stock (in shares)		51
Exercise of common stock options (in shares)	523	523
Exercise of common stock options	$ 1,903		1,903
Vesting of restricted stock units (in shares)		457
Common stock issued under employee stock purchase plan (in shares)		30
Common stock issued under employee stock purchase plan	1,179		1,179
Stock-based compensation expense	10,742		10,742
Unrealized losses on marketable securities, net of tax of $(2)	(14)			(14)
Net income	40,373				40,373
Temporary equity, ending balance (in shares) at Jun. 30, 2017						0
Temporary equity, ending balance at Jun. 30, 2017						$ 0
Ending balance (in shares) at Jun. 30, 2017		39,059
Ending balance at Jun. 30, 2017	$ 488,978	$ 4	$ 309,717	$ (30)	$ 179,287

CONDENSED CONSOLIDATED STATEME8

CONDENSED CONSOLIDATED STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (Parenthetical) $ in Thousands	6 Months Ended
	Jun. 30, 2016USD ($)
Statement of Stockholders' Equity [Abstract]
Offering costs incurred	$ 3,824

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 40,373	$ 32,195
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	5,841	3,820
Gain on disposal of property and equipment	(47)	0
Stock-based compensation	10,742	9,461
Deferred income taxes	(13,939)	(454)
Other non-cash charges	158	0
Change in fair value of preferred stock warrant liability	0	3,361
Changes in operating assets and liabilities:
Accounts receivable	25,216	(36,629)
Inventory	(10,005)	4,656
Prepaid expenses and other current assets	(6,435)	(1,026)
Deferred product costs	(286)	1,994
Restricted cash	1,593	0
Other assets	(4,560)	(109)
Accounts payable	(12,364)	22,929
Accrued liabilities	925	2,826
Deferred revenue	155	(672)
Other long-term liabilities	459	568
Net cash provided by operating activities	37,826	42,920
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property and equipment	(8,006)	(8,033)
Purchases of marketable securities	(233,246)	0
Sales and maturities of marketable securities	100,300	0
Deposits	(30)	(23)
Net cash used in investing activities	(140,982)	(8,056)
CASH FLOWS FROM FINANCING ACTIVITIES:
Payment of capital lease obligation	0	(34)
Proceeds from initial public offering, net of underwriting discounts and commissions	0	97,757
Payment of public offering costs	(201)	(1,471)
Proceeds from the issuance of common stock under stock-based compensation plans	3,082	283
Net cash provided by financing activities	2,881	96,535
Net (decrease) increase in cash and cash equivalents	(100,275)	131,399
Cash and cash equivalents—Beginning of period	206,402	27,610
Cash and cash equivalents—End of period	106,127	159,009
Supplemental cash flow disclosures:
Cash paid for income taxes, net of refunds	833	2,819
Supplemental disclosure of non-cash investing and financing activities:
Capital expenditures incurred but not yet paid	140	1,474
Public offering costs incurred but not yet paid	0	528
Accretion of redemption value on redeemable convertible preferred stock	0	1,628
Accretion of redeemable convertible preferred stock issuance costs	0	94
Conversion of redeemable convertible preferred stock into common stock	0	72,502
Reclassification to additional paid-in capital of fair value of preferred stock warrant liability upon conversion to common stock warrants	$ 0	$ 6,615

NATURE OF THE BUSINESS AND OPER

NATURE OF THE BUSINESS AND OPERATIONS	6 Months Ended
	Jun. 30, 2017
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 is a leading provider of high-speed coherent interconnect products that are designed to improve the capacity, performance, intelligence and cost of communications networks relied upon by cloud infrastructure operators and content and communications service providers. The Company’s products include a series of low-power coherent digital signal processors and silicon photonic integrated circuits integrated into families of optical interconnect modules with transmission speeds ranging from 100 to 400 gigabits per second for use in long-haul, metro and inter-data center markets. The Company is also developing optical interconnect modules that will enable transmission speeds of one terabit (1,000 gigabits) per second and above. The Company is headquartered in Maynard, Massachusetts, and has established wholly-owned subsidiaries in North America, Europe and Asia as part of the Company’s global expansion. On May 18, 2016, the Company closed its initial public offering (“IPO”), in which the Company issued and sold 4,570,184 shares of common stock and certain selling stockholders sold an additional 604,816 shares, inclusive of the underwriters’ option to purchase additional shares that was exercised in full. The price per share to the public was $23.00 . The Company received aggregate proceeds of approximately $97.8 million from the IPO, net of underwriters’ discounts and commissions, before deduction of offering expenses of approximately $4.3 million . The Company received no proceeds from the sale of shares by the selling stockholders. Upon the closing of the IPO, all shares of the Company’s outstanding redeemable convertible preferred stock (the “preferred stock”) automatically converted into 24,177,495 shares of common stock. On October 13, 2016, the Company closed a follow-on public offering in which the Company issued and sold 1,210,302 shares of common stock and certain selling stockholders sold an additional 3,289,698 shares. The underwriters’ option to purchase up to an additional 675,000 shares from certain of the selling stockholders was not exercised. The price per share to the public was $100.00 . The Company received aggregate proceeds of $116.8 million from the follow-on offering, net of underwriters’ discounts and commissions, before deduction of offering expenses of approximately $1.2 million . The Company received no proceeds from the sale of shares by the selling stockholders.

BASIS OF PRESENTATION AND SUMMA

BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
Basis of Presentation and Summary of Significant Accounting Policies	BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES The unaudited condensed consolidated financial statements include the accounts of Acacia Communications, Inc. and its Subsidiaries and have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). Accordingly, they do not include all of the information and footnotes required by GAAP for annual financial statements. For further information, these condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and related notes contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016, which was filed with the SEC on February 23, 2017. There have been no significant changes in the Company’s accounting policies from those disclosed in the Annual Report on Form 10-K that have had a material impact on the Company’s condensed consolidated financial statements. The unaudited condensed consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements as of and for the year ended December 31, 2016 , and in management’s opinion, include all adjustments, consisting of only normal recurring adjustments, necessary for the fair statement of the Company’s condensed consolidated balance sheet as of June 30, 2017 , its condensed consolidated income statements for the three and six months ended June 30, 2017 and 2016 , its condensed consolidated statements of comprehensive income for the three and six months ended June 30, 2017 and 2016 , its condensed consolidated statements of redeemable convertible preferred stock and stockholders’ equity for the six months ended June 30, 2017 and 2016 , and its condensed consolidated statements of cash flows for the six months ended June 30, 2017 and 2016 . All intercompany balances and transactions have been eliminated in consolidation. The financial data and the other financial information disclosed in the notes to these condensed consolidated financial statements related to these three- and six -month periods are also unaudited. The results of operations for the three and six months ended June 30, 2017 are not necessarily indicative of the results to be expected for the full fiscal year or any other period. Use of Estimates The preparation of unaudited condensed 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 unaudited condensed consolidated financial statements and the reported amounts of revenue and expenses during the reporting period. Actual results could differ from those estimates. Recently Issued Accounting Pronouncements In May 2017, the Financial Accounting Standards Board ("FASB") issued Accounting Standard Update ("ASU") 2017-09, Compensation – Stock Compensation (Topic 718): Scope of Modification Accounting ("ASU 2017-09"). ASU 2017-09 provides clarity about which changes to terms or conditions of a share-based payment award require modification accounting. Specifically, an entity would not apply modification accounting if the fair value, vesting conditions, and classification of the awards are the same immediately before and after the modification. The amendments in ASU 2017-09 are effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2017, with early adoption permitted, and is required to be applied on a prospective basis for awards modified on or after the adoption date. The Company does not expect any material impact of this guidance on its condensed consolidated financial statements due to the infrequency of share-based payment award modifications. In March 2017, the FASB issued ASU 2017-08, Receivables – Nonrefundable Fees and Other Costs (Topic 310-20): Premium Amortization on Purchased Callable Debt Securities (“ASU 2017-08”). ASU 2017-08 amends the amortization period for certain purchased callable debt securities held at a premium to the earliest call date in order to reduce diversity in practice and provide more decision-useful information. The amendments in ASU 2017-08 are effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years with early adoption permitted, and is required to be applied on a modified retrospective basis through a cumulative-effect adjustment directly to retained earnings as of the beginning of the period of adoption. The Company does not anticipate that this guidance will have a material impact on its condensed consolidated financial statements because all of the Company's callable debt securities held at a premium are already amortized to the earliest call date. In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (Topic 320): Restricted Cash (“ASU 2016-18”). ASU 2016-18 will require amounts generally described as restricted cash or restricted cash equivalents to be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. The amendments in ASU 2016-18 are effective for fiscal years beginning after December 15, 2017 and interim periods within those fiscal years, and must be applied using a retrospective approach with earlier adoption permitted. The Company expects its condensed consolidated statements of cash flows to be impacted by the amount of restricted cash held by the Company in each period. In October 2016, the FASB issued ASU 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory (“ASU 2016-16”). ASU 2016-16 requires an entity to recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. The amendments in ASU 2016-16 are effective for fiscal years beginning after December 15, 2017, and must be applied using a modified retrospective approach with earlier adoption permitted for annual reporting periods for which financial statements have not yet been issued. The Company does not anticipate that this guidance will have a material impact on its condensed consolidated financial statements. In June 2016, the FASB issued 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 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 credit losses, and recording credit losses related to available-for-sale securities through an allowance for credit losses. The amendments in ASU 2016-13 are effective for fiscal years beginning after December 15, 2019, and must be applied using a modified retrospective approach with earlier adoption permitted for fiscal years beginning after December 15, 2018. The Company is currently evaluating the impact of this guidance on its condensed consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) (“ASU 2016-02”). ASU 2016-02 will require lessees to recognize a right-of-use asset and lease liability on the balance sheet for virtually all leases. For the income statement, ASU 2016-02 retains a dual model requiring leases to be classified as either operating or financing leases. Operating leases will result in straight-line expense, and financing leases will have a front-loaded expense pattern with an interest expense component. The amendments in ASU 2016-02 are effective for fiscal years beginning after December 15, 2018, and must be applied using a modified retrospective approach with earlier adoption permitted. The Company is currently evaluating the impact of this guidance on its condensed consolidated financial statements. In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606) (“ASU 2014-09”), which affects any entity that either enters into contracts with customers to transfer goods and services or enters into contracts for the transfer of nonfinancial assets. ASU 2014-09 will replace most existing revenue recognition guidance in GAAP when it becomes effective. The standard’s core principle is that a company will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. In doing so, companies will need to use more judgment and make more estimates than under the currently effective guidance. These may include identifying performance obligations in the contract, estimating the amount of variable consideration to include in the transaction price, and allocating the transaction price to each separate performance obligation. The new guidance is required to be applied retrospectively to each prior reporting period presented or retrospectively with the cumulative effect of initially applying it recognized at the date of initial application. ASU 2014-09 was initially to be effective for annual periods beginning after December 15, 2016, including interim periods within that period. In August 2015, the FASB issued ASU 2015-14, Revenue from Contracts with Customers , which delays the effective date of ASU 2014-09 by one year and allows for early adoption as of the original effective date. In March 2016, the FASB issued ASU 2016-08, Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations , which clarifies certain principal versus agent considerations. In April 2016, the FASB issued ASU 2016-10, Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing , which clarifies certain guidance related to identifying performance obligations and licensing. In May 2016, the FASB issued ASU 2016-12, Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients , which addresses improvements to the guidance on collectability, noncash consideration and completed contracts at transition. In December 2016, the FASB issued ASU 2016-20, Technical Corrections and Improvements to Topic 606, Revenue from Contracts with Customers, which addresses clarifications and corrections in various areas, including contract costs and disclosures. The Company has commenced its evaluation of the impact that ASU 2014-09 may have on its condensed consolidated financial statements, including evaluation of the disclosure requirements under the new standard. Although its evaluation is ongoing, the Company does not anticipate that the adoption of this standard will have a significant impact on its condensed consolidated financial statements as, upon adoption, most revenue will continue to be recognized at a point-in-time when control transfers which is similar to the current revenue recognition model. The Company plans to adopt this guidance on January 1, 2018, using the modified retrospective adoption method applied to those contracts that were not completed as of that date. As the Company continues its evaluation, it is also identifying and preparing to implement changes to accounting policies, business processes and internal controls to support the new accounting and disclosure requirements.

FINANCIAL INSTRUMENTS

FINANCIAL INSTRUMENTS	6 Months Ended
	Jun. 30, 2017
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 June 30, 2017 and December 31, 2016 (in thousands): June 30, 2017 Gross Unrealized Amortized Cost Gains Losses (1) Estimated Fair Value Cash and Cash Equivalents Marketable Securities Cash $ 76,213 $ — $ — $ 76,213 $ 76,213 $ — Money market funds 5,018 — — 5,018 5,018 — Repurchase agreements 20,000 — — 20,000 20,000 — U.S. treasury bonds 12,192 — (3 ) 12,189 — 12,189 Commercial paper 55,322 — (1 ) 55,321 2,996 52,325 Certificates of deposit 23,448 6 (1 ) 23,453 1,900 21,553 Asset-backed securities 35,021 4 (7 ) 35,018 — 35,018 Corporate debt securities 115,735 18 (59 ) 115,694 — 115,694 Total $ 342,949 $ 28 $ (71 ) $ 342,906 $ 106,127 $ 236,779 (1) Losses represent marketable securities that were in loss positions for less than one year. December 31, 2016 Gross Unrealized Amortized Cost Gains Losses (1) Estimated Fair Value Cash and Cash Equivalents Marketable Securities Cash $ 81,230 $ — $ — $ 81,230 $ 81,230 $ — Money market funds 118,174 — — 118,174 118,174 — U.S. treasury bonds 15,017 — (2 ) 15,015 — 15,015 Commercial paper 49,673 — — 49,673 5,997 43,676 Corporate debt securities 46,339 2 (27 ) 46,314 1,001 45,313 Total $ 310,433 $ 2 $ (29 ) $ 310,406 $ 206,402 $ 104,004 (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): Three Months Ended June 30, 2017 Six Months Ended June 30, 2017 Proceeds from the sales and maturities of marketable securities $ 61,400 $ 100,300 Realized gains $ 3 $ 4 Realized losses $ — $ — The contractual maturities of short-term and long-term marketable securities held at June 30, 2017 and December 31, 2016 are as follows (in thousands): June 30, 2017 December 31, 2016 Amortized Cost Basis Aggregate Fair Value Amortized Cost Basis Aggregate Fair Value Due within one year $ 176,332 $ 176,293 $ 104,031 $ 104,004 Due after 1 year through 2 years 60,491 60,486 — — Total $ 236,823 $ 236,779 $ 104,031 $ 104,004 At June 30, 2017 , the Company believed that the unrealized losses on its available-for-sale investments were temporary. The investments with unrealized losses consisted primarily of corporate debt securities. In making the determination that the decline in fair value of these securities was temporary, the Company considered various factors, including, but not limited to: the length of time each security was in an unrealized loss position; 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.

INVENTORY

INVENTORY	6 Months Ended
	Jun. 30, 2017
Inventory Disclosure [Abstract]
INVENTORY	INVENTORY Inventory consisted of the following as of June 30, 2017 and December 31, 2016 (in thousands): June 30, 2017 December 31, 2016 Raw materials $ 24,003 $ 14,385 Work-in-process 2,917 3,235 Finished goods 14,766 14,061 Inventory $ 41,686 $ 31,681

PROPERTY AND EQUIPMENT

PROPERTY AND EQUIPMENT	6 Months Ended
	Jun. 30, 2017
Property, Plant and Equipment [Abstract]
PROPERTY AND EQUIPMENT	PROPERTY AND EQUIPMENT Property and equipment consisted of the following as of June 30, 2017 and December 31, 2016 (in thousands): June 30, 2017 December 31, 2016 Engineering laboratory equipment $ 35,364 $ 31,096 Computer software 1,617 1,381 Computer equipment 3,677 2,572 Furniture and fixtures 2,908 408 Leasehold improvements 2,222 1,032 Construction in progress 1,672 5,954 Total property and equipment 47,460 42,443 Less: Accumulated depreciation (21,695 ) (17,319 ) Property and equipment, net $ 25,765 $ 25,124 Depreciation expense was $3.0 million and $2.1 million for the three months ended June 30, 2017 and 2016 , respectively, and $5.8 million and $3.8 million for the six months ended June 30, 2017 and 2016 , respectively.

ACCRUED LIABILITIES

ACCRUED LIABILITIES	6 Months Ended
	Jun. 30, 2017
Payables and Accruals [Abstract]
ACCRUED LIABILITIES	ACCRUED LIABILITIES Accrued liabilities consisted of the following as of June 30, 2017 and December 31, 2016 (in thousands): June 30, 2017 December 31, 2016 Employee-related liabilities $ 5,551 $ 6,235 Outsourced foundry services 346 1,811 Goods and services received not invoiced 7,977 9,024 Accrued income taxes 464 670 Accrued manufacturing related expenses 6,980 5,255 Warranty reserve 4,859 2,158 Other accrued liabilities 4,921 4,710 Accrued liabilities $ 31,098 $ 29,863

FAIR VALUE MEASUREMENT

FAIR VALUE MEASUREMENT	6 Months Ended
	Jun. 30, 2017
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 a remaining maturity of three months or less to be cash equivalents. The Company’s cash equivalents consist of money market funds, repurchase agreements, commercial paper, certificates of deposit and corporate debt securities with an original maturity of three months or less. The Company’s investments in money market funds, repurchase agreements, commercial paper, certificates of deposit, asset-backed securities, corporate bonds and U.S. government agency debt securities, which are classified as Level 2 within the fair value hierarchy, 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 June 30, 2017 and December 31, 2016 (in thousands): June 30, 2017 Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Fair Value Assets: Money market funds $ — $ 5,018 $ — $ 5,018 Repurchase agreements — 20,000 — 20,000 U.S. treasury bonds — 12,189 — 12,189 Commercial paper — 55,321 — 55,321 Certificates of deposit — 23,453 — 23,453 Asset-backed securities — 35,018 — 35,018 Corporate debt securities — 115,694 — 115,694 Total $ — $ 266,693 $ — $ 266,693 December 31, 2016 Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Fair Value Assets: Money market funds $ — $ 118,174 $ — $ 118,174 U.S. treasury bonds — 15,015 — 15,015 Commercial paper — 49,673 — 49,673 Corporate debt securities — 46,314 — 46,314 Total $ — $ 229,176 $ — $ 229,176 There have been no transfers between fair value measurement levels during the three or six months ended June 30, 2017 . For certain other financial instruments, including accounts receivable, restricted cash, accounts payable, and other current liabilities, the carrying amounts approximate their fair value due to the relatively short maturity of these balances. Preferred Stock Warrants Prior to the closing of the Company’s IPO, the Company remeasured the fair value of its preferred stock warrants at each balance sheet date. Any changes in fair value were recognized as a component of other income (expense) in the condensed consolidated income statements. The valuation technique used to measure fair value for the Company’s preferred stock warrants, which were considered Level 3 fair value estimates within the fair value hierarchy, was the Black-Scholes option pricing model. The significant unobservable inputs used in the fair value measurement of the Company’s preferred stock warrants was the fair value of the Company’s series B and series C preferred stock. The Company also utilized risk-free interest rate, expected dividend yield, expected volatility and expected term as observable inputs with the fair value of the series B and series C preferred stock in determining the fair value of the preferred stock warrants. There is not a direct interrelationship between the unobservable inputs and the observable inputs. A summary of the changes in the Company’s preferred stock warrant liability measured at fair value using significant unobservable inputs (Level 3) for the three and six months ended June 30, 2016 is as follows (in thousands): Three Months Ended June 30, 2016 Six Months Ended June 30, 2016 Preferred stock warrant liability at beginning of period $ 3,006 $ 3,254 Change in fair value 3,609 3,361 Reclassification of preferred stock warrant liability to additional paid-in capital upon conversion to common stock warrants (6,615 ) $ (6,615 ) Preferred stock warrant liability at end of period $ — $ — The warrants to purchase shares of preferred stock were converted into warrants to purchase shares of common stock upon the closing of the IPO.

STOCK COMPENSATION PLANS

STOCK COMPENSATION PLANS	6 Months Ended
	Jun. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
STOCK COMPENSATION PLANS	STOCK COMPENSATION PLANS The following table summarizes the classification of stock-based compensation in the condensed consolidated income statements for the three and six months ended June 30, 2017 and 2016 (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 Cost of revenue $ 511 $ 660 $ 953 $ 692 Research and development 3,779 5,389 6,771 5,578 Sales, general and administrative 1,820 3,122 3,018 3,191 Total stock-based compensation $ 6,110 $ 9,171 $ 10,742 $ 9,461 The following table summarizes stock-based compensation expense by award type for the three and six months ended June 30, 2017 and 2016 (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 Stock options $ 655 $ 507 $ 1,321 $ 768 Restricted stock awards 29 18 58 47 Restricted stock units 5,126 8,495 8,812 8,495 Employee stock purchase plan 300 151 551 151 Total stock-based compensation $ 6,110 $ 9,171 $ 10,742 $ 9,461 Stock Options A summary of stock option activity under the Company’s equity incentive plans for the six months ended June 30, 2017 is as follows: Number of Options (in thousands) Weighted-Average Exercise Price Weighted-Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (in thousands) Outstanding at December 31, 2016 2,354 $ 7.10 7.4 $ 129,288 Granted — Exercised (523 ) $ 3.64 $ 27,050 Cancelled (8 ) $ 8.42 Outstanding at June 30, 2017 1,823 $ 8.08 7.1 $ 62,255 Vested and expected to vest at: June 30, 2017 1,823 $ 8.08 7.1 $ 62,255 December 31, 2016 2,354 $ 7.10 7.4 $ 129,288 Exercisable at: June 30, 2017 819 $ 3.54 6.2 $ 31,079 December 31, 2016 975 $ 1.78 6.1 $ 58,458 As of June 30, 2017 and December 31, 2016 , there was $6.2 million and $7.6 million , respectively, of unrecognized compensation cost related to unvested common stock options, which is expected to be recognized over weighted-average periods of 2.6 years and 3.1 years, respectively. The weighted-average grant date fair value of stock options granted during the three and six months ended June 30, 2016 was $22.35 and $8.97 , respectively. No stock options were granted by the Company during the three or six months ended June 30, 2017 . Restricted Stock Units During the six months ended June 30, 2017 , the Company granted 441,000 restricted stock units ("RSUs") to employees and executives under the 2016 Equity Incentive Plan that vest upon the satisfaction of a service condition, generally over four years. The cost of any 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 straight-line basis over the requisite vesting period. During the six months ended June 30, 2017 , the Company granted 436,000 RSUs to executive officers that include a market condition and a performance condition in addition to a service condition (“performance-based RSUs” or “PRSUs”). Each PRSU represents the right to receive one share of the Company’s common stock when and if the applicable vesting conditions are satisfied. The number of PRSUs that are subject to the service condition is determined based on the achievement of certain market and performance objectives over a two -year period running from January 1, 2017 through December 31, 2018 (the “Earned PRSUs”). Thirty-three percent of any Earned PRSUs will vest on the later of (i) March 17, 2019 and (ii) the date that the number of Earned PRSUs is determined by the Compensation Committee after December 31, 2018. Thereafter, an additional 33% of the Earned PRSUs will vest on March 17, 2020 and the remaining 34% of the Earned PRSUs will vest on March 17, 2021 . Vesting of Earned PRSUs is subject to the applicable officer’s continued provision of services to the Company through the applicable vesting date. The number of PRSUs that become Earned PRSUs will be determined based on the extent to which the Company achieves (i) a revenue growth objective, based on the compound annual growth rate of the Company’s total revenue by measuring the Company’s revenue for fiscal year 2018 against the Company’s revenue for fiscal year 2016 (the “Revenue Growth Objective”), and/or (ii) a stock price objective during the two -year period (the “Stock Price Objective”). If neither the Revenue Growth Objective nor the Stock Price Objective is achieved, none of the PRSUs will become Earned PRSUs. Any PRSUs that do not become Earned PRSUs shall be forfeited once the number of Earned PRSUs is determined by the Compensation Committee after December 31, 2018. For the PRSUs, the related stock-based compensation expense is amortized using the accelerated method over the vesting period of four years. The Company estimates the fair value of the PRSUs using management’s best estimate of whether it is probable or not probable that the Revenue Growth Objective will be satisfied using the most currently available projections of future revenue performance, which is reassessed at each reporting period. Changes in the subjective and probability-based assumptions can materially affect the estimate of fair value of stock-based compensation and consequently, the related amount recognized in the Company’s condensed consolidated income statements. The Company estimated the fair value of the PRSUs using a Monte Carlo valuation model on the date of grant, using the following assumptions: Risk-free interest rate 1.3% Expected dividend yield None Expected volatility 58.3% Expected term (in years) 1.8 Grant date fair value of underlying shares $55.02 As soon as practicable following each vesting date of RSUs, including PRSUs, 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 six months ended June 30, 2017 is as follows: RSUs (in thousands) Weighted-Average Grant Date Fair Value Outstanding at December 31, 2016 2,034 $ 21.09 Granted 877 $ 56.41 Vested (457 ) $ 16.36 Cancelled (7 ) $ 32.50 Outstanding at June 30, 2017 2,447 $ 34.59 The granted amount includes the 436,000 PRSUs which is the maximum number that were granted to executives during the six months ended June 30, 2017 . As of June 30, 2017 and December 31, 2016 , there was $53.5 million and $32.1 million , respectively, of total unrecognized compensation cost related to unvested RSUs, which is expected to be recognized over weighted-average periods of 3.3 years and 3.4 years, respectively.

NET INCOME PER SHARE ATTRIBUTAB

NET INCOME PER SHARE ATTRIBUTABLE TO COMMON STOCKHOLDERS	6 Months Ended
	Jun. 30, 2017
Earnings Per Share [Abstract]
NET INCOME PER SHARE ATTRIBUTABLE TO COMMON STOCKHOLDERS	NET INCOME PER SHARE ATTRIBUTABLE TO COMMON STOCKHOLDERS Basic and diluted net income per share attributable to common stockholders is presented in conformity with the two-class method required for participating securities. The Company considers its preferred stock to be participating securities. In the event a cash dividend is paid on common stock, the holders of preferred stock are also entitled to a proportionate share of any such dividend as if they were holders of common stock (on an as-if converted basis). The holders of the preferred stock do not have a contractual obligation to share in losses. In accordance with the two-class method, earnings allocated to these participating securities and the related number of outstanding shares of the participating securities, which include contractual participation rights in undistributed earnings, have been excluded from the computation of basic and diluted net income per share attributable to common stockholders. As a result of the conversion of preferred stock on May 18, 2016, no earnings were allocated to participating securities during the three and six months ended June 30, 2017 . The following table sets forth the computation of the Company’s basic and diluted net income per share attributable to common stockholders (in thousands, except per share amounts): Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 Numerator: Net income $ 4,664 $ 17,598 $ 40,373 $ 32,195 Less: preferred stock accretion — (636 ) — (1,722 ) Less: undistributed earnings attributable to participating securities — (6,455 ) — (17,467 ) Net income attributable to common stockholders - basic and diluted $ 4,664 $ 10,507 $ 40,373 $ 13,006 Denominator: Weighted-average shares used to compute net income per share attributable to common stockholders - basic 38,756 20,760 38,546 13,751 Dilutive effect of stock options, unvested restricted stock and restricted stock units, preferred stock warrants, and employee stock purchase plan 2,826 3,613 3,093 3,176 Weighted-average shares used to compute net income per share attributable to common stockholders - diluted 41,582 24,373 41,639 16,927 Net income per share attributable to common stockholders Basic $ 0.12 $ 0.51 $ 1.05 $ 0.95 Diluted $ 0.11 $ 0.43 $ 0.97 $ 0.77 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: Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 Options to purchase common stock 90 15 90 270 Unvested restricted stock units and awards 562 20 381 137 Preferred stock warrants — 245 — 245 As discussed further in Note 8, in March 2017, the Company granted 436,000 PRSUs to executives that include market, performance and service conditions. As the market and performance criteria associated with the vesting of those awards have not been satisfied as of June 30, 2017 , the Company has excluded those shares from the table above and the calculation of diluted net income per share attributable to common stockholders.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	6 Months Ended
	Jun. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Leases The Company’s principal facilities are located in Maynard, Massachusetts and Holmdel, New Jersey and are leased by the Company under non-cancelable operating leases that expire in February 2025, with respect to the Massachusetts facility, and December 2021, with respect to the New Jersey facility. The Company also leases office space in various locations with expiration dates between 2018 and 2021 . Several of the lease agreements include leasehold improvement incentives, escalating lease payments, renewal provisions and other provisions which require the Company to pay taxes, insurance and maintenance costs. All of the Company’s facility leases are accounted for as operating leases. Rent expense is recorded over each respective lease term on a straight-line basis. Rent expense was $1.2 million and $0.3 million for the three months ended June 30, 2017 and 2016 , respectively, and $2.7 million and $0.6 million for the six months ended June 30, 2017 and 2016 , respectively. Future minimum lease payments due under these non-cancelable lease agreements as of June 30, 2017 , are as follows (in thousands): Amounts Remaining 2017 $ 1,674 2018 3,113 2019 3,047 2020 3,067 2021 3,039 Thereafter 7,387 Total $ 21,327 The Holmdel, New Jersey and Maynard, Massachusetts leases entered into during 2016 included tenant improvements which were partially funded by the Company. Under these lease agreements, the Company will not have title to the tenant improvements. Therefore, as the Company funded its portion of the improvements, it recorded a prepaid lease asset that will be amortized over the lease term. As of June 30, 2017 , the Company was committed to approximately $0.6 million of remaining tenant improvement costs related to these leases which is expected to be paid in the third quarter of 2017. 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 product warranty liability, which is included as a component of accrued liabilities on the condensed consolidated balance sheets, are set forth in the table below (in thousands). The reserves below do not include reserves established as a result of the manufacturing process quality issue described below under the heading "Manufacturing Process Quality Reserve." Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 Warranty reserve, beginning of period $ 2,113 $ 1,147 $ 2,158 $ 763 Provisions made to warranty reserve during the period 4,771 1,156 5,971 1,786 Charges against warranty reserve during the period (2,025 ) (997 ) (3,270 ) (1,243 ) Warranty reserve, end of period $ 4,859 $ 1,306 $ 4,859 $ 1,306 Manufacturing Process Quality Reserve In May 2017, the Company announced a quality issue at one of its three contract manufacturers that affected a portion of the approximate 1,300 AC400 units and 5,100 CFP units manufactured by the contract manufacturer over an approximate four month period (the "Quality Issue"). As a result of the Quality Issue, the Company established reserves to cover anticipated costs, including cost estimates for product repairs, rework of component inventory with the contract manufacturer and rescreening costs. The Quality Issue warranty reserve of $2.8 million was recorded as a component of accrued liabilities in the Company's condensed consolidated balance sheets as of June 30, 2017 . An additional $5.0 million was reserved against estimated affected inventory on-hand at the contract manufacturer and in-transit returns as of June 30, 2017 . The Company's estimates of the Quality Issue costs are subject to change as customers return the potentially affected units and final testing is performed. Legal Contingencies On January 22, 2016, ViaSat, Inc. filed a suit 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 suit 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, which ViaSat denied in its response filed March 16, 2016. The lawsuit is still pending and discovery is ongoing. The Company is continuing to evaluate ViaSat’s claims, but based on the information available to the Company today, the Company currently believes that this suit will not have a material adverse effect on the Company’s business or its condensed consolidated financial position, results of operations or cash flows. On July 28, 2017, the Company filed a suit against ViaSat asserting commercial disparagement, libel, slander of title, unfair competition, intentional interference with advantageous relations and intentional interference with contractual relations. 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 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 its condensed 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. 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 three and six months ended June 30, 2017 and 2016 , the Company did not experience any losses related to these indemnification obligations. The Company does not expect significant claims related to these indemnification obligations, and consequently, has concluded that the fair value of these obligations is not material. Accordingly, as of June 30, 2017 and December 31, 2016 , no amounts have been accrued related to such indemnification provisions.

INCOME TAXES

INCOME TAXES	6 Months Ended
	Jun. 30, 2017
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES 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. The Company does not provide for federal income taxes on the undistributed earnings of its foreign subsidiaries as such earnings are reinvested indefinitely. The Company’s tax provision for interim periods is determined using an estimate of its annual effective tax rate, adjusted for discrete items arising in that quarter. In each quarter, the Company updates its estimate of the annual effective tax rate, and if the estimated annual tax rate changes, the Company makes a cumulative adjustment in that quarter. The Company’s quarterly tax provision, and its quarterly estimate of its annual effective tax rate, are subject to significant volatility due to several factors, including the Company’s ability to accurately predict its pre-tax income and loss in multiple jurisdictions, as well as the portions of stock-based compensation that will either not generate tax benefits or the tax benefit is unpredictable and reflected when realized by employees. For the three months ended June 30, 2017 , the Company recorded a benefit for income taxes of $10.5 million as compared to a tax provision of $2.2 million for the three months ended June 30, 2016 , resulting in an effective tax rate of 179.8% and 11.2% for the three months ended June 30, 2017 and 2016, respectively. For the six months ended June 30, 2017 , the Company recorded a benefit from income taxes of $15.9 million as compared to a tax provision of $3.8 million for the six months ended June 30, 2016 , resulting in an effective tax rate of (65.2)% and 10.5% for the six months ended June 30, 2017 and 2016, respectively. The benefits for income taxes recorded in the three and six months ended June 30, 2017 are mainly due to the favorable effect of foreign statutory tax rates applicable to income earned outside the United States under the Company’s corporate structure and the recognition of excess tax benefits from the taxable compensation on share-based awards. The Company’s historical provision for income taxes is not necessarily reflective of its future results of operations. As of June 30, 2017 and December 31, 2016 , the Company identified $3.8 million and $3.1 million , respectively, of gross uncertain tax positions. Included in those balances as of June 30, 2017 and December 31, 2016 are $1.9 million and $1.5 million , respectively, of tax benefits that, if recognized, would impact the effective tax rate. These have been accrued for as long-term liabilities on the Company’s condensed consolidated balance sheets. The Company’s existing tax positions will 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. During the three and six months ended June 30, 2017 and 2016 , the amounts recorded related to the accrual of interest and penalties were immaterial in each period.

SEGMENT INFORMATION AND GEOGRAP

SEGMENT INFORMATION AND GEOGRAPHIC DATA	6 Months Ended
	Jun. 30, 2017
Segment Reporting [Abstract]
SEGMENT INFORMATION AND GEOGRAPHIC DATA	SEGMENT INFORMATION AND GEOGRAPHIC DATA 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 president and chief executive officer, in deciding how to allocate resources and assess performance. The Company’s CODM evaluates the Company’s financial information and resources and assesses the performance of these resources on a consolidated basis. Since the Company operates in one operating segment, all required financial segment information can be found in the condensed consolidated financial statements. Revenue by geographic region, based on ship-to destinations, was as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 United States $ 23,814 $ 27,048 $ 36,227 $ 40,016 China 29,367 45,968 86,349 87,352 Germany 9,649 25,564 22,615 44,720 Thailand 5,115 — 16,719 — Other 10,953 17,612 31,655 28,593 Total revenue $ 78,898 $ 116,192 $ 193,565 $ 200,681 Total long-lived assets by geographic region consisted of the following as of June 30, 2017 and December 31, 2016 (in thousands): June 30, 2017 December 31, 2016 United States $ 16,737 $ 14,026 China 1,420 2,235 Thailand 7,249 8,070 Other 359 793 Total long-lived assets $ 25,765 $ 25,124

CONCENTRATIONS OF RISK

CONCENTRATIONS OF RISK	6 Months Ended
	Jun. 30, 2017
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 three and six months ended June 30, 2017 and 2016 were as follows: Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 A 28 % 32 % 36 % 38 % B 19 % 27 % 14 % 24 % C 15 % 10 % * 11 % * Less than 10% of revenue in the period indicated Customers that accounted for equal to or greater than 10% of accounts receivable at June 30, 2017 and December 31, 2016 were as follows: June 30, 2017 December 31, 2016 A 26 % 26 % B 11 % 19 % C 22 % 15 % Supplier Concentration The Company purchases a substantial portion of its inventory from contract manufacturers and component suppliers located in Japan, Canada, Thailand and the United States. For the three and six months ended June 30, 2017 and 2016 , total inventory purchased from each of the suppliers was as follows: Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 W 11 % * 30 % * X 20 % 46 % 23 % 44 % Y * 22 % 28 % 16 % Z 12 % 20 % 17 % 20 % * Less than 10% of total inventory purchased in the period indicated The Company also outsources certain engineering projects to a foundry located in the United States. During the three months ended June 30, 2017 and 2016 , the Company incurred 21% and 22% , respectively, of its total research and development costs with the U.S. foundry. During the six months ended June 30, 2017 and 2016 , the Company incurred 12% and 18% , respectively, of its total research and development costs with the U.S. foundry.

RELATED PARTIES

RELATED PARTIES	6 Months Ended
	Jun. 30, 2017
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. During the three and six months ended June 30, 2017 and 2016, the Company’s contract manufacturers made purchases from ADI of approximately $1.0 million , $2.2 million , $1.1 million , and $1.8 million , respectively.

BASIS OF PRESENTATION AND SUM24

BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
Use of Estimates	Use of Estimates The preparation of unaudited condensed 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 unaudited condensed consolidated financial statements and the reported amounts of revenue and expenses during the reporting period. Actual results could differ from those estimates.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements In May 2017, the Financial Accounting Standards Board ("FASB") issued Accounting Standard Update ("ASU") 2017-09, Compensation – Stock Compensation (Topic 718): Scope of Modification Accounting ("ASU 2017-09"). ASU 2017-09 provides clarity about which changes to terms or conditions of a share-based payment award require modification accounting. Specifically, an entity would not apply modification accounting if the fair value, vesting conditions, and classification of the awards are the same immediately before and after the modification. The amendments in ASU 2017-09 are effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2017, with early adoption permitted, and is required to be applied on a prospective basis for awards modified on or after the adoption date. The Company does not expect any material impact of this guidance on its condensed consolidated financial statements due to the infrequency of share-based payment award modifications. In March 2017, the FASB issued ASU 2017-08, Receivables – Nonrefundable Fees and Other Costs (Topic 310-20): Premium Amortization on Purchased Callable Debt Securities (“ASU 2017-08”). ASU 2017-08 amends the amortization period for certain purchased callable debt securities held at a premium to the earliest call date in order to reduce diversity in practice and provide more decision-useful information. The amendments in ASU 2017-08 are effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years with early adoption permitted, and is required to be applied on a modified retrospective basis through a cumulative-effect adjustment directly to retained earnings as of the beginning of the period of adoption. The Company does not anticipate that this guidance will have a material impact on its condensed consolidated financial statements because all of the Company's callable debt securities held at a premium are already amortized to the earliest call date. In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows (Topic 320): Restricted Cash (“ASU 2016-18”). ASU 2016-18 will require amounts generally described as restricted cash or restricted cash equivalents to be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. The amendments in ASU 2016-18 are effective for fiscal years beginning after December 15, 2017 and interim periods within those fiscal years, and must be applied using a retrospective approach with earlier adoption permitted. The Company expects its condensed consolidated statements of cash flows to be impacted by the amount of restricted cash held by the Company in each period. In October 2016, the FASB issued ASU 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory (“ASU 2016-16”). ASU 2016-16 requires an entity to recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. The amendments in ASU 2016-16 are effective for fiscal years beginning after December 15, 2017, and must be applied using a modified retrospective approach with earlier adoption permitted for annual reporting periods for which financial statements have not yet been issued. The Company does not anticipate that this guidance will have a material impact on its condensed consolidated financial statements. In June 2016, the FASB issued 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 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 credit losses, and recording credit losses related to available-for-sale securities through an allowance for credit losses. The amendments in ASU 2016-13 are effective for fiscal years beginning after December 15, 2019, and must be applied using a modified retrospective approach with earlier adoption permitted for fiscal years beginning after December 15, 2018. The Company is currently evaluating the impact of this guidance on its condensed consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) (“ASU 2016-02”). ASU 2016-02 will require lessees to recognize a right-of-use asset and lease liability on the balance sheet for virtually all leases. For the income statement, ASU 2016-02 retains a dual model requiring leases to be classified as either operating or financing leases. Operating leases will result in straight-line expense, and financing leases will have a front-loaded expense pattern with an interest expense component. The amendments in ASU 2016-02 are effective for fiscal years beginning after December 15, 2018, and must be applied using a modified retrospective approach with earlier adoption permitted. The Company is currently evaluating the impact of this guidance on its condensed consolidated financial statements. In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606) (“ASU 2014-09”), which affects any entity that either enters into contracts with customers to transfer goods and services or enters into contracts for the transfer of nonfinancial assets. ASU 2014-09 will replace most existing revenue recognition guidance in GAAP when it becomes effective. The standard’s core principle is that a company will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. In doing so, companies will need to use more judgment and make more estimates than under the currently effective guidance. These may include identifying performance obligations in the contract, estimating the amount of variable consideration to include in the transaction price, and allocating the transaction price to each separate performance obligation. The new guidance is required to be applied retrospectively to each prior reporting period presented or retrospectively with the cumulative effect of initially applying it recognized at the date of initial application. ASU 2014-09 was initially to be effective for annual periods beginning after December 15, 2016, including interim periods within that period. In August 2015, the FASB issued ASU 2015-14, Revenue from Contracts with Customers , which delays the effective date of ASU 2014-09 by one year and allows for early adoption as of the original effective date. In March 2016, the FASB issued ASU 2016-08, Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations , which clarifies certain principal versus agent considerations. In April 2016, the FASB issued ASU 2016-10, Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing , which clarifies certain guidance related to identifying performance obligations and licensing. In May 2016, the FASB issued ASU 2016-12, Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients , which addresses improvements to the guidance on collectability, noncash consideration and completed contracts at transition. In December 2016, the FASB issued ASU 2016-20, Technical Corrections and Improvements to Topic 606, Revenue from Contracts with Customers, which addresses clarifications and corrections in various areas, including contract costs and disclosures. The Company has commenced its evaluation of the impact that ASU 2014-09 may have on its condensed consolidated financial statements, including evaluation of the disclosure requirements under the new standard. Although its evaluation is ongoing, the Company does not anticipate that the adoption of this standard will have a significant impact on its condensed consolidated financial statements as, upon adoption, most revenue will continue to be recognized at a point-in-time when control transfers which is similar to the current revenue recognition model. The Company plans to adopt this guidance on January 1, 2018, using the modified retrospective adoption method applied to those contracts that were not completed as of that date. As the Company continues its evaluation, it is also identifying and preparing to implement changes to accounting policies, business processes and internal controls to support the new accounting and disclosure requirements.

FINANCIAL INSTRUMENTS (Tables)

FINANCIAL INSTRUMENTS (Tables)	6 Months Ended
	Jun. 30, 2017
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 June 30, 2017 and December 31, 2016 (in thousands): June 30, 2017 Gross Unrealized Amortized Cost Gains Losses (1) Estimated Fair Value Cash and Cash Equivalents Marketable Securities Cash $ 76,213 $ — $ — $ 76,213 $ 76,213 $ — Money market funds 5,018 — — 5,018 5,018 — Repurchase agreements 20,000 — — 20,000 20,000 — U.S. treasury bonds 12,192 — (3 ) 12,189 — 12,189 Commercial paper 55,322 — (1 ) 55,321 2,996 52,325 Certificates of deposit 23,448 6 (1 ) 23,453 1,900 21,553 Asset-backed securities 35,021 4 (7 ) 35,018 — 35,018 Corporate debt securities 115,735 18 (59 ) 115,694 — 115,694 Total $ 342,949 $ 28 $ (71 ) $ 342,906 $ 106,127 $ 236,779 (1) Losses represent marketable securities that were in loss positions for less than one year. December 31, 2016 Gross Unrealized Amortized Cost Gains Losses (1) Estimated Fair Value Cash and Cash Equivalents Marketable Securities Cash $ 81,230 $ — $ — $ 81,230 $ 81,230 $ — Money market funds 118,174 — — 118,174 118,174 — U.S. treasury bonds 15,017 — (2 ) 15,015 — 15,015 Commercial paper 49,673 — — 49,673 5,997 43,676 Corporate debt securities 46,339 2 (27 ) 46,314 1,001 45,313 Total $ 310,433 $ 2 $ (29 ) $ 310,406 $ 206,402 $ 104,004 (1) Losses represent marketable securities that were in loss positions for less than one year.
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): Three Months Ended June 30, 2017 Six Months Ended June 30, 2017 Proceeds from the sales and maturities of marketable securities $ 61,400 $ 100,300 Realized gains $ 3 $ 4 Realized losses $ — $ —
Contractual Maturities of Short-term and Long-Term Marketable Securities Held	The contractual maturities of short-term and long-term marketable securities held at June 30, 2017 and December 31, 2016 are as follows (in thousands): June 30, 2017 December 31, 2016 Amortized Cost Basis Aggregate Fair Value Amortized Cost Basis Aggregate Fair Value Due within one year $ 176,332 $ 176,293 $ 104,031 $ 104,004 Due after 1 year through 2 years 60,491 60,486 — — Total $ 236,823 $ 236,779 $ 104,031 $ 104,004

INVENTORY (Tables)

INVENTORY (Tables)	6 Months Ended
	Jun. 30, 2017
Inventory Disclosure [Abstract]
Schedule of Inventory	Inventory consisted of the following as of June 30, 2017 and December 31, 2016 (in thousands): June 30, 2017 December 31, 2016 Raw materials $ 24,003 $ 14,385 Work-in-process 2,917 3,235 Finished goods 14,766 14,061 Inventory $ 41,686 $ 31,681

PROPERTY AND EQUIPMENT (Tables)

PROPERTY AND EQUIPMENT (Tables)	6 Months Ended
	Jun. 30, 2017
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment	Property and equipment consisted of the following as of June 30, 2017 and December 31, 2016 (in thousands): June 30, 2017 December 31, 2016 Engineering laboratory equipment $ 35,364 $ 31,096 Computer software 1,617 1,381 Computer equipment 3,677 2,572 Furniture and fixtures 2,908 408 Leasehold improvements 2,222 1,032 Construction in progress 1,672 5,954 Total property and equipment 47,460 42,443 Less: Accumulated depreciation (21,695 ) (17,319 ) Property and equipment, net $ 25,765 $ 25,124

ACCRUED LIABILITIES (Tables)

ACCRUED LIABILITIES (Tables)	6 Months Ended
	Jun. 30, 2017
Payables and Accruals [Abstract]
Schedule of Accrued Liabilities	Accrued liabilities consisted of the following as of June 30, 2017 and December 31, 2016 (in thousands): June 30, 2017 December 31, 2016 Employee-related liabilities $ 5,551 $ 6,235 Outsourced foundry services 346 1,811 Goods and services received not invoiced 7,977 9,024 Accrued income taxes 464 670 Accrued manufacturing related expenses 6,980 5,255 Warranty reserve 4,859 2,158 Other accrued liabilities 4,921 4,710 Accrued liabilities $ 31,098 $ 29,863

FAIR VALUE MEASUREMENT (Tables)

FAIR VALUE MEASUREMENT (Tables)	6 Months Ended
	Jun. 30, 2017
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 June 30, 2017 and December 31, 2016 (in thousands): June 30, 2017 Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Fair Value Assets: Money market funds $ — $ 5,018 $ — $ 5,018 Repurchase agreements — 20,000 — 20,000 U.S. treasury bonds — 12,189 — 12,189 Commercial paper — 55,321 — 55,321 Certificates of deposit — 23,453 — 23,453 Asset-backed securities — 35,018 — 35,018 Corporate debt securities — 115,694 — 115,694 Total $ — $ 266,693 $ — $ 266,693 December 31, 2016 Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Fair Value Assets: Money market funds $ — $ 118,174 $ — $ 118,174 U.S. treasury bonds — 15,015 — 15,015 Commercial paper — 49,673 — 49,673 Corporate debt securities — 46,314 — 46,314 Total $ — $ 229,176 $ — $ 229,176
Summary of Changes in the Preferred Stock Warrant Liability Measured at Fair Value Using Significant Unobservable Inputs (Level 3)	A summary of the changes in the Company’s preferred stock warrant liability measured at fair value using significant unobservable inputs (Level 3) for the three and six months ended June 30, 2016 is as follows (in thousands): Three Months Ended June 30, 2016 Six Months Ended June 30, 2016 Preferred stock warrant liability at beginning of period $ 3,006 $ 3,254 Change in fair value 3,609 3,361 Reclassification of preferred stock warrant liability to additional paid-in capital upon conversion to common stock warrants (6,615 ) $ (6,615 ) Preferred stock warrant liability at end of period $ — $ —

STOCK COMPENSATION PLANS (Table

STOCK COMPENSATION PLANS (Tables)	6 Months Ended
	Jun. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Classification of Stock-based Compensation	The following table summarizes the classification of stock-based compensation in the condensed consolidated income statements for the three and six months ended June 30, 2017 and 2016 (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 Cost of revenue $ 511 $ 660 $ 953 $ 692 Research and development 3,779 5,389 6,771 5,578 Sales, general and administrative 1,820 3,122 3,018 3,191 Total stock-based compensation $ 6,110 $ 9,171 $ 10,742 $ 9,461
Schedule of Stock-Based Compensation Expense by Award Type	The following table summarizes stock-based compensation expense by award type for the three and six months ended June 30, 2017 and 2016 (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 Stock options $ 655 $ 507 $ 1,321 $ 768 Restricted stock awards 29 18 58 47 Restricted stock units 5,126 8,495 8,812 8,495 Employee stock purchase plan 300 151 551 151 Total stock-based compensation $ 6,110 $ 9,171 $ 10,742 $ 9,461
Stock Option Activity	A summary of stock option activity under the Company’s equity incentive plans for the six months ended June 30, 2017 is as follows: Number of Options (in thousands) Weighted-Average Exercise Price Weighted-Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (in thousands) Outstanding at December 31, 2016 2,354 $ 7.10 7.4 $ 129,288 Granted — Exercised (523 ) $ 3.64 $ 27,050 Cancelled (8 ) $ 8.42 Outstanding at June 30, 2017 1,823 $ 8.08 7.1 $ 62,255 Vested and expected to vest at: June 30, 2017 1,823 $ 8.08 7.1 $ 62,255 December 31, 2016 2,354 $ 7.10 7.4 $ 129,288 Exercisable at: June 30, 2017 819 $ 3.54 6.2 $ 31,079 December 31, 2016 975 $ 1.78 6.1 $ 58,458
Weighted-Average Assumptions Used to Estimate Fair Value	The Company estimated the fair value of the PRSUs using a Monte Carlo valuation model on the date of grant, using the following assumptions: Risk-free interest rate 1.3% Expected dividend yield None Expected volatility 58.3% Expected term (in years) 1.8 Grant date fair value of underlying shares $55.02
Summary of Changes in Company's RSU	A summary of the changes in the Company’s RSUs during the six months ended June 30, 2017 is as follows: RSUs (in thousands) Weighted-Average Grant Date Fair Value Outstanding at December 31, 2016 2,034 $ 21.09 Granted 877 $ 56.41 Vested (457 ) $ 16.36 Cancelled (7 ) $ 32.50 Outstanding at June 30, 2017 2,447 $ 34.59

NET INCOME PER SHARE ATTRIBUT31

NET INCOME PER SHARE ATTRIBUTABLE TO COMMON STOCKHOLDERS (Tables)	6 Months Ended
	Jun. 30, 2017
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 attributable to common stockholders (in thousands, except per share amounts): Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 Numerator: Net income $ 4,664 $ 17,598 $ 40,373 $ 32,195 Less: preferred stock accretion — (636 ) — (1,722 ) Less: undistributed earnings attributable to participating securities — (6,455 ) — (17,467 ) Net income attributable to common stockholders - basic and diluted $ 4,664 $ 10,507 $ 40,373 $ 13,006 Denominator: Weighted-average shares used to compute net income per share attributable to common stockholders - basic 38,756 20,760 38,546 13,751 Dilutive effect of stock options, unvested restricted stock and restricted stock units, preferred stock warrants, and employee stock purchase plan 2,826 3,613 3,093 3,176 Weighted-average shares used to compute net income per share attributable to common stockholders - diluted 41,582 24,373 41,639 16,927 Net income per share attributable to common stockholders Basic $ 0.12 $ 0.51 $ 1.05 $ 0.95 Diluted $ 0.11 $ 0.43 $ 0.97 $ 0.77
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: Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 Options to purchase common stock 90 15 90 270 Unvested restricted stock units and awards 562 20 381 137 Preferred stock warrants — 245 — 245

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Tables)	6 Months Ended
	Jun. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Future Annual Minimum Lease Payments	Future minimum lease payments due under these non-cancelable lease agreements as of June 30, 2017 , are as follows (in thousands): Amounts Remaining 2017 $ 1,674 2018 3,113 2019 3,047 2020 3,067 2021 3,039 Thereafter 7,387 Total $ 21,327
Schedule of Changes in Product Warrant Liability	Changes in the Company’s product warranty liability, which is included as a component of accrued liabilities on the condensed consolidated balance sheets, are set forth in the table below (in thousands). The reserves below do not include reserves established as a result of the manufacturing process quality issue described below under the heading "Manufacturing Process Quality Reserve." Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 Warranty reserve, beginning of period $ 2,113 $ 1,147 $ 2,158 $ 763 Provisions made to warranty reserve during the period 4,771 1,156 5,971 1,786 Charges against warranty reserve during the period (2,025 ) (997 ) (3,270 ) (1,243 ) Warranty reserve, end of period $ 4,859 $ 1,306 $ 4,859 $ 1,306

SEGMENT INFORMATION AND GEOGR33

SEGMENT INFORMATION AND GEOGRAPHIC DATA (Tables)	6 Months Ended
	Jun. 30, 2017
Segment Reporting [Abstract]
Summary of Revenue by Geographic Region	Revenue by geographic region, based on ship-to destinations, was as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 United States $ 23,814 $ 27,048 $ 36,227 $ 40,016 China 29,367 45,968 86,349 87,352 Germany 9,649 25,564 22,615 44,720 Thailand 5,115 — 16,719 — Other 10,953 17,612 31,655 28,593 Total revenue $ 78,898 $ 116,192 $ 193,565 $ 200,681
Summary of Total Long-Lived Assets by Geographic Region	Total long-lived assets by geographic region consisted of the following as of June 30, 2017 and December 31, 2016 (in thousands): June 30, 2017 December 31, 2016 United States $ 16,737 $ 14,026 China 1,420 2,235 Thailand 7,249 8,070 Other 359 793 Total long-lived assets $ 25,765 $ 25,124

CONCENTRATIONS OF RISK (Tables)

CONCENTRATIONS OF RISK (Tables)	6 Months Ended
	Jun. 30, 2017
Customer Concentration Risk
Concentration Risk [Line Items]
Summary of Concentrations of Risk	Customers with revenue equal to or greater than 10% of total revenue for the three and six months ended June 30, 2017 and 2016 were as follows: Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 A 28 % 32 % 36 % 38 % B 19 % 27 % 14 % 24 % C 15 % 10 % * 11 % * Less than 10% of revenue in the period indicated Customers that accounted for equal to or greater than 10% of accounts receivable at June 30, 2017 and December 31, 2016 were as follows: June 30, 2017 December 31, 2016 A 26 % 26 % B 11 % 19 % C 22 % 15 %
Supplier Concentration Risk
Concentration Risk [Line Items]
Summary of Concentrations of Risk	For the three and six months ended June 30, 2017 and 2016 , total inventory purchased from each of the suppliers was as follows: Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 W 11 % * 30 % * X 20 % 46 % 23 % 44 % Y * 22 % 28 % 16 % Z 12 % 20 % 17 % 20 % * Less than 10% of total inventory purchased in the period indicated

NATURE OF THE BUSINESS AND OP35

NATURE OF THE BUSINESS AND OPERATIONS (Details)	Oct. 13, 2016USD ($)$ / sharesshares	May 18, 2016USD ($)$ / sharesshares	Jun. 30, 2017USD ($)GBTB	Jun. 30, 2016USD ($)
Organization Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Optical interconnect modules transmission speed | TB			1
Aggregate proceeds from IPO			$ 0	$ 97,757,000
IPO
Organization Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Common stock, issued and sold (in shares) | shares		4,570,184
Additional shares sold by selling stockholders (in shares) | shares		604,816
Price per share (in USD per share) | $ / shares		$ 23
Aggregate proceeds from IPO		$ 97,800,000
Offering expenses		$ 4,300,000
Conversion of redeemable preferred stock into common stock (in shares) | shares		24,177,495
Stock offered through certain selling stockholders
Organization Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Proceeds from sale of shares		$ 0
Follow-on offering
Organization Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Common stock, issued and sold (in shares) | shares	1,210,302
Additional shares sold by selling stockholders (in shares) | shares	3,289,698
Price per share (in USD per share) | $ / shares	$ 100
Offering expenses	$ 1,200,000
Proceeds from sale of shares	116,800,000
Proceeds from sale of shares	$ 0
Minimum
Organization Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Optical interconnect modules transmission speed | GB			100
Maximum
Organization Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Optical interconnect modules transmission speed | GB			400
Maximum | Underwriters
Organization Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Additional shares sold by selling stockholders (in shares) | shares	675,000

FINANCIAL INSTRUMENTS - Schedul

FINANCIAL INSTRUMENTS - Schedule of Cash, Cash Equivalents and Short- and Long-term Marketable Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2015
Schedule Of Cash Cash Equivalents And Marketable Securities [Line Items]
Amortized Cost	$ 342,949	$ 310,433
Gross Unrealized Gains	28	2
Gross Unrealized Losses	(71)	(29)
Estimated Fair Value	342,906	310,406
Cash and Cash Equivalents	106,127	206,402	$ 159,009	$ 27,610
Marketable Securities	236,779	104,004
Corporate debt securities
Schedule Of Cash Cash Equivalents And Marketable Securities [Line Items]
Amortized Cost	115,735	46,339
Gross Unrealized Gains	18	2
Gross Unrealized Losses	(59)	(27)
Estimated Fair Value	115,694	46,314
Cash and Cash Equivalents	0	1,001
Marketable Securities	115,694	45,313
Cash
Schedule Of Cash Cash Equivalents And Marketable Securities [Line Items]
Amortized Cost	76,213	81,230
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	76,213	81,230
Cash and Cash Equivalents	76,213	81,230
Marketable Securities	0	0
Money market funds
Schedule Of Cash Cash Equivalents And Marketable Securities [Line Items]
Amortized Cost	5,018	118,174
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	5,018	118,174
Cash and Cash Equivalents	5,018	118,174
Marketable Securities	0	0
Repurchase agreements
Schedule Of Cash Cash Equivalents And Marketable Securities [Line Items]
Amortized Cost	20,000
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Estimated Fair Value	20,000
Cash and Cash Equivalents	20,000
Marketable Securities	0
U.S. treasury bonds
Schedule Of Cash Cash Equivalents And Marketable Securities [Line Items]
Amortized Cost	12,192	15,017
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(3)	(2)
Estimated Fair Value	12,189	15,015
Cash and Cash Equivalents	0	0
Marketable Securities	12,189	15,015
Commercial paper
Schedule Of Cash Cash Equivalents And Marketable Securities [Line Items]
Amortized Cost	55,322	49,673
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(1)	0
Estimated Fair Value	55,321	49,673
Cash and Cash Equivalents	2,996	5,997
Marketable Securities	52,325	$ 43,676
Certificates of deposit
Schedule Of Cash Cash Equivalents And Marketable Securities [Line Items]
Amortized Cost	23,448
Gross Unrealized Gains	6
Gross Unrealized Losses	(1)
Estimated Fair Value	23,453
Cash and Cash Equivalents	1,900
Marketable Securities	21,553
Asset-backed securities
Schedule Of Cash Cash Equivalents And Marketable Securities [Line Items]
Amortized Cost	35,021
Gross Unrealized Gains	4
Gross Unrealized Losses	(7)
Estimated Fair Value	35,018
Cash and Cash Equivalents	0
Marketable Securities	$ 35,018

FINANCIAL INSTRUMENTS - Proceed

FINANCIAL INSTRUMENTS - Proceeds from Sales and Maturities of Marketable Securities (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2017	Jun. 30, 2016
Investments, Debt and Equity Securities [Abstract]
Proceeds from the sales and maturities of marketable securities	$ 61,400	$ 100,300	$ 0
Realized gains	3	4
Realized losses	$ 0	$ 0

FINANCIAL INSTRUMENTS - Contrac

FINANCIAL INSTRUMENTS - Contractual Maturities of Short-term and Long-Term Marketable Securities Held (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Due within one year, Amortized Cost Basis	$ 176,332	$ 104,031
Due within one year, Aggregate Fair Value	176,293	104,004
Due after 1 year through 2 years, Amortized Cost Basis	60,491	0
Due after 1 year through 2 years, Aggregate Fair Value	60,486	0
Amortized Cost Basis	236,823	104,031
Aggregate Fair Value	$ 236,779	$ 104,004

INVENTORY - Schedule of Invento

INVENTORY - Schedule of Inventory (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Inventory Disclosure [Abstract]
Raw materials	$ 24,003	$ 14,385
Work-in-process	2,917	3,235
Finished goods	14,766	14,061
Inventory	$ 41,686	$ 31,681

PROPERTY AND EQUIPMENT - Schedu

PROPERTY AND EQUIPMENT - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 47,460	$ 42,443
Less: Accumulated depreciation	(21,695)	(17,319)
Property and equipment, net	25,765	25,124
Engineering laboratory equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	35,364	31,096
Computer software
Property, Plant and Equipment [Line Items]
Total property and equipment	1,617	1,381
Computer equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	3,677	2,572
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Total property and equipment	2,908	408
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total property and equipment	2,222	1,032
Construction in progress
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 1,672	$ 5,954

PROPERTY AND EQUIPMENT - Narrat

PROPERTY AND EQUIPMENT - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 3,000	$ 2,100	$ 5,841	$ 3,820

ACCRUED LIABILITIES - Schedule

ACCRUED LIABILITIES - Schedule of Accrued Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015
Payables and Accruals [Abstract]
Employee-related liabilities	$ 5,551		$ 6,235
Outsourced foundry services	346		1,811
Goods and services received not invoiced	7,977		9,024
Accrued income taxes	464		670
Accrued manufacturing related expenses	6,980		5,255
Warranty reserve	4,859	$ 2,113	2,158	$ 1,306	$ 1,147	$ 763
Other accrued liabilities	4,921		4,710
Accrued liabilities	$ 31,098		$ 29,863

FAIR VALUE MEASUREMENT - Summar

FAIR VALUE MEASUREMENT - Summary of Assets And Liabilities Measured at Fair Value on Recurring Basis (Details) - Recurring Basis - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	$ 266,693	$ 229,176
Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	0	0
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	266,693	229,176
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	0	0
Repurchase agreements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	20,000
Repurchase agreements | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	0
Repurchase agreements | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	20,000
Repurchase agreements | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	0
U.S. treasury bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	12,189	15,015
U.S. treasury bonds | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	0	0
U.S. treasury bonds | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	12,189	15,015
U.S. treasury bonds | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	0	0
Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	55,321	49,673
Commercial paper | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	0	0
Commercial paper | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	55,321	49,673
Commercial paper | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	0	0
Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	23,453
Certificates of deposit | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	0
Certificates of deposit | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	23,453
Certificates of deposit | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	0
Asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	35,018
Asset-backed securities | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	0
Asset-backed securities | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	35,018
Asset-backed securities | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	0
Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	115,694	46,314
Corporate debt securities | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	0	0
Corporate debt securities | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	115,694	46,314
Corporate debt securities | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	0	0
Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	5,018	118,174
Money market funds | Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	0	0
Money market funds | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	5,018	118,174
Money market funds | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	$ 0	$ 0

FAIR VALUE MEASUREMENT - Narrat

FAIR VALUE MEASUREMENT - Narrative (Details) - USD ($)	3 Months Ended	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2017
Fair Value Disclosures [Abstract]
Transfers between fair value measurement levels	$ 0	$ 0

FAIR VALUE MEASUREMENT- Summary

FAIR VALUE MEASUREMENT- Summary of Changes in the Preferred Stock Warrant Liability Measured at Fair Value Using Significant Unobservable Inputs (Level 3) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Fair Value Disclosures [Abstract]
Preferred stock warrant liability at beginning of period		$ 3,006		$ 3,254
Change in fair value	$ 0	3,609	$ 0	3,361
Reclassification of preferred stock warrant liability to additional paid-in capital upon conversion to common stock warrants		(6,615)		(6,615)
Preferred stock warrant liability at end of period		$ 0		$ 0

STOCK COMPENSATION PLANS - Clas

STOCK COMPENSATION PLANS - Classification of Stock-based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	$ 6,110	$ 9,171	$ 10,742	$ 9,461
Cost of revenue
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	511	660	953	692
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	3,779	5,389	6,771	5,578
Sales, general and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	$ 1,820	$ 3,122	$ 3,018	$ 3,191

STOCK COMPENSATION PLANS - Sche

STOCK COMPENSATION PLANS - Schedule of Stock-Based Compensation Expense by Award Type (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	$ 6,110	$ 9,171	$ 10,742	$ 9,461
Employee stock purchase plan
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	300	151	551	151
Stock options
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	655	507	1,321	768
Restricted stock awards
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	29	18	58	47
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	$ 5,126	$ 8,495	$ 8,812	$ 8,495

STOCK COMPENSATION PLANS - Stoc

STOCK COMPENSATION PLANS - Stock Option Activity (Details) $ / shares in Units, shares in Thousands, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2017USD ($)$ / sharesshares	Dec. 31, 2016USD ($)$ / sharesshares
Number of Options, Abstract
Number of options outstanding at December 31, 2016 (in shares)	2,354
Number of options granted (in shares)	0
Number of options exercised (in shares)	(523)
Number of options cancelled (in shares)	(8)
Number of options outstanding at June 30, 2017 (in shares)	1,823	2,354
Number of options vested and expected to vest (in shares)	1,823	2,354
Number of options exercisable (in shares)	819	975
Weighted-Average Exercise Price, Abstract
Weighted-average exercise price outstanding at December 31, 2016 (in USD per share) | $ / shares	$ 7.10
Options exercised, Weighted-average exercise price (in USD per share) | $ / shares	3.64
Options cancelled, Weighted-average exercise price (in USD per share) | $ / shares	8.42
Weighted-average exercise price outstanding at June 30, 2017 (in USD per share) | $ / shares	8.08	$ 7.10
Options vested and expected to vest, Weighted-average exercise price (in USD per share) | $ / shares	8.08	7.10
Options exercisable, Weighted-average exercise price (in USD per share) | $ / shares	$ 3.54	$ 1.78
Weighted-Average Remaining Contract Term, Abstract
Options outstanding, Weighted-average remaining contractual term (in years)	7 years 1 month 6 days	7 years 4 months 24 days
Options vested and expected to vest, Weighted-average remaining contractual term (in years)	7 years 1 month 6 days	7 years 4 months 24 days
Options exercisable, Weighted-average remaining contractual term (in years)	6 years 2 months 12 days	6 years 1 month 6 days
Aggregate Intrinsic Value, Abstract
Options outstanding, Aggregate intrinsic value at December 31, 2016 | $	$ 129,288
Options exercised, Aggregate intrinsic value | $	27,050
Options outstanding, Aggregate intrinsic value at June 30, 2017 | $	62,255	$ 129,288
Options vested and expected to vest, Aggregate intrinsic value | $	62,255	129,288
Options exercisable, Aggregate intrinsic value | $	$ 31,079	$ 58,458

STOCK COMPENSATION PLANS - Narr

STOCK COMPENSATION PLANS - Narrative (Details) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Mar. 31, 2017	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options granted (in shares)				0
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation cost, stock options		$ 6,200,000		$ 6,200,000		$ 7,600,000
Weighted average recognition period				2 years 7 months 6 days		3 years 1 month 6 days
Weighted average grant date fair value (in USD per share)			$ 22.35		$ 8.97
Number of options granted (in shares)		0
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average recognition period				3 years 3 months 18 days		3 years 4 months 24 days
Restricted stock units granted (in shares)				877,000
Vested awards settled in cash				$ 0
Unrecognized stock-based compensation expense		$ 53,500,000		$ 53,500,000		$ 32,100,000
Restricted stock units | Employees and Executives | 2016 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units granted (in shares)				441,000
Awards vesting period				4 years
Performance-Based RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards vesting period				4 years
Right to receive number of common stock upon achievement of vesting conditions				1
Stock price objective period				2 years
Performance-Based RSUs | Executive
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units granted (in shares)	436,000			436,000
Performance-Based RSUs | Executive | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units granted (in shares)				436,000
Earned PRSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance objective period				2 years
Earned PRSUs | Vest on March 17, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of earned PRSUs				33.00%
Earned PRSUs | Vest on March 17, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of earned PRSUs				33.00%
Earned PRSUs | Vest on March 17, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of earned PRSUs				34.00%

STOCK COMPENSATION PLANS - Weig

STOCK COMPENSATION PLANS - Weighted-Average Assumptions Used to Estimate Fair Value (Details) - Performance-Based RSUs	6 Months Ended
	Jun. 30, 2017$ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	1.30%
Expected dividend yield	0.00%
Expected volatility	58.30%
Expected term (in years)	1 year 9 months 18 days
Grant date fair value of underlying shares (in USD per share)	$ 55.02

STOCK COMPENSATION PLANS - Chan

STOCK COMPENSATION PLANS - Changes in Company Restricted Stock Units (Details) - Restricted stock units shares in Thousands	6 Months Ended
	Jun. 30, 2017$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Shares outstanding at December 31, 2016 (in shares) | shares	2,034
Granted (in shares) | shares	877
Vested (in shares) | shares	(457)
Cancelled (in shares) | shares	(7)
Shares outstanding at June 30, 2017 (in shares) | shares	2,447
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Shares outstanding, Weighted-average grant date fair value at December 31, 2016 (in USD per share) | $ / shares	$ 21.09
Granted, Weighted-average grant date fair value (in USD per share) | $ / shares	56.41
Vested, Weighted-average grant date fair value (in USD per share) | $ / shares	16.36
Cancelled, Weighted-average grant date fair value (in USD per share) | $ / shares	32.50
Shares outstanding, Weighted-average grant date fair value at June 30, 2017 (in USD per share) | $ / shares	$ 34.59

NET INCOME PER SHARE ATTRIBUT52

NET INCOME PER SHARE ATTRIBUTABLE TO COMMON STOCKHOLDERS - Narrative (Details) - USD ($)	1 Months Ended	3 Months Ended	6 Months Ended
	Mar. 31, 2017	Jun. 30, 2017	Jun. 30, 2017
Earnings Per Share [Line Items]
Earnings allocated to participating securities		$ 0	$ 0
Performance-Based RSUs | Executive
Earnings Per Share [Line Items]
Restricted stock units granted (in shares)	436,000		436,000

NET INCOME PER SHARE ATTRIBUT53

NET INCOME PER SHARE ATTRIBUTABLE TO COMMON STOCKHOLDERS - Computation of Basic and Diluted Net Income Per Share Attributable to Common Stockholders (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Numerator:
Net income	$ 4,664	$ 17,598	$ 40,373	$ 32,195
Less: preferred stock accretion	0	(636)	0	(1,722)
Less: undistributed earnings attributable to participating securities	0	(6,455)	0	(17,467)
Net income attributable to common stockholders - basic	4,664	10,507	40,373	13,006
Net income attributable to common stockholders - diluted	$ 4,664	$ 10,507	$ 40,373	$ 13,006
Denominator:
Weighted-average shares used to compute net income per share attributable to common stockholders - basic (in shares)	38,756	20,760	38,546	13,751
Dilutive effect of stock options, unvested restricted stock and restricted stock units, preferred stock warrants, and employee stock purchase plan (in shares)	2,826	3,613	3,093	3,176
Weighted-average shares used to compute net income per share attributable to common stockholders - diluted (in shares)	41,582	24,373	41,639	16,927
Net income per share attributable to common stockholders
Basic (in USD per share)	$ 0.12	$ 0.51	$ 1.05	$ 0.95
Diluted (in USD per share)	$ 0.11	$ 0.43	$ 0.97	$ 0.77

NET INCOME PER SHARE ATTRIBUT54

NET INCOME PER SHARE ATTRIBUTABLE TO COMMON STOCKHOLDERS - Summary of Common Stock Equivalents Excluded from Computation of Diluted Net Income Per Share (Details) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Preferred stock warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares excluded from computation of earnings per share (in shares)	0	245	0	245
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)	90	15	90	270
Unvested restricted stock units and awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares excluded from computation of earnings per share (in shares)	562	20	381	137

COMMITMENTS AND CONTINGENCIES -

COMMITMENTS AND CONTINGENCIES - Narrative (Details) $ in Millions	1 Months Ended	3 Months Ended			6 Months Ended
	May 31, 2017contract_manufacturerAC400_UnitCFP_Unit	Sep. 30, 2017USD ($)	Jun. 30, 2017USD ($)	Jun. 30, 2016USD ($)	Jun. 30, 2017USD ($)	Jun. 30, 2016USD ($)
Loss Contingencies [Line Items]
Operating leases rent expense			$ 1.2	$ 0.3	$ 2.7	$ 0.6
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
Contract manufacturer quality issue
Loss Contingencies [Line Items]
Number of contract manufacturers with quality issue | contract_manufacturer	1
Number of contract manufacturers | contract_manufacturer	3
Quality issue warranty accrual			2.8		$ 2.8
Inventory reserves			$ 5		$ 5
Contract manufacturer quality issue | AC400 Unit
Loss Contingencies [Line Items]
Defective units | AC400_Unit	1,300
Contract manufacturer quality issue | CFP Unit
Loss Contingencies [Line Items]
Defective units | CFP_Unit	5,100
Improvement costs expected to be paid | Massachusetts facility
Loss Contingencies [Line Items]
Tenant improvements cost		$ 0.6

COMMITMENTS AND CONTINGENCIES56

COMMITMENTS AND CONTINGENCIES - Future Annual Minimum Lease Payments (Details) $ in Thousands	Jun. 30, 2017USD ($)
Commitments and Contingencies Disclosure [Abstract]
Remaining 2,017	$ 1,674
2,018	3,113
2,019	3,047
2,020	3,067
2,021	3,039
Thereafter	7,387
Total	$ 21,327

COMMITMENTS AND CONTINGENCIES57

COMMITMENTS AND CONTINGENCIES - Schedule of Changes in Product Warrant Liability (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
Warranty reserve, beginning of period	$ 2,113	$ 1,147	$ 2,158	$ 763
Provisions made to warranty reserve during the period	4,771	1,156	5,971	1,786
Charges against warranty reserve during the period	(2,025)	(997)	(3,270)	(1,243)
Warranty reserve, end of period	$ 4,859	$ 1,306	$ 4,859	$ 1,306

INCOME TAXES - Narrative (Detai

INCOME TAXES - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Income Tax Disclosure [Abstract]
(Benefit) provision for income taxes	$ (10,511)	$ 2,219	$ (15,932)	$ 3,796
Effective income tax rate	(179.80%)	11.20%	(65.20%)	10.50%
Uncertain tax positions	$ 3,800		$ 3,800		$ 3,100
Unrecognized tax benefits that, if recognized, would favorably impact effective tax rate	$ 1,900		$ 1,900		$ 1,500

SEGMENT INFORMATION AND GEOGR59

SEGMENT INFORMATION AND GEOGRAPHIC DATA - Narrative (Details)	6 Months Ended
	Jun. 30, 2017segment
Segment Reporting [Abstract]
Number of operating segments	1

SEGMENT INFORMATION AND GEOGR60

SEGMENT INFORMATION AND GEOGRAPHIC DATA - Summary of Revenue by Geographic Region (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Reporting Information [Line Items]
Revenue	$ 78,898	$ 116,192	$ 193,565	$ 200,681
United States
Segment Reporting Information [Line Items]
Revenue	23,814	27,048	36,227	40,016
China
Segment Reporting Information [Line Items]
Revenue	29,367	45,968	86,349	87,352
Germany
Segment Reporting Information [Line Items]
Revenue	9,649	25,564	22,615	44,720
Thailand
Segment Reporting Information [Line Items]
Revenue	5,115	0	16,719	0
Other
Segment Reporting Information [Line Items]
Revenue	$ 10,953	$ 17,612	$ 31,655	$ 28,593

SEGMENT INFORMATION AND GEOGR61

SEGMENT INFORMATION AND GEOGRAPHIC DATA - Summary of Total Long-Lived Assets by Geographic Region (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Property and equipment, net	$ 25,765	$ 25,124
United States
Segment Reporting Information [Line Items]
Property and equipment, net	16,737	14,026
China
Segment Reporting Information [Line Items]
Property and equipment, net	1,420	2,235
Thailand
Segment Reporting Information [Line Items]
Property and equipment, net	7,249	8,070
Other
Segment Reporting Information [Line Items]
Property and equipment, net	$ 359	$ 793

CONCENTRATIONS OF RISK - Summar

CONCENTRATIONS OF RISK - Summary of Customer Concentration of Total Revenue (Details) - Customer Concentration Risk - Revenue	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Customer A
Concentration Risk [Line Items]
Concentration risk, percentage	28.00%	32.00%	36.00%	38.00%
Customer B
Concentration Risk [Line Items]
Concentration risk, percentage	19.00%	27.00%	14.00%	24.00%
Customer C
Concentration Risk [Line Items]
Concentration risk, percentage	15.00%	10.00%		11.00%

CONCENTRATIONS OF RISK - Summ63

CONCENTRATIONS OF RISK - Summary of Customer Concentration of Accounts Receivable (Details) - Customer Concentration Risk - Accounts Receivable	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Customer A
Concentration Risk [Line Items]
Concentration risk, percentage	26.00%	26.00%
Customer B
Concentration Risk [Line Items]
Concentration risk, percentage	11.00%	19.00%
Customer C
Concentration Risk [Line Items]
Concentration risk, percentage	22.00%	15.00%

CONCENTRATIONS OF RISK - Summ64

CONCENTRATIONS OF RISK - Summary of Supplier Concentration (Details) - Supplier Concentration Risk - Purchases	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Supplier W
Concentration Risk [Line Items]
Concentration risk, percentage	11.00%		30.00%
Supplier X
Concentration Risk [Line Items]
Concentration risk, percentage	20.00%	46.00%	23.00%	44.00%
Supplier Y
Concentration Risk [Line Items]
Concentration risk, percentage		22.00%	28.00%	16.00%
Supplier Z
Concentration Risk [Line Items]
Concentration risk, percentage	12.00%	20.00%	17.00%	20.00%

CONCENTRATIONS OF RISK - Narrat

CONCENTRATIONS OF RISK - Narrative (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Supplier Concentration Risk | Revenue | Research and development
Concentration Risk [Line Items]
Concentration risk, percentage	21.00%	22.00%	12.00%	18.00%

RELATED PARTIES - Narrative (De

RELATED PARTIES - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
ADI
Related Party Transaction [Line Items]
Purchase from related party	$ 1	$ 1.1	$ 2.2	$ 1.8