Quantenna Communications (QTNA) 10-Q 29 Oct 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Oct. 26, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	QUANTENNA COMMUNICATIONS INC
Entity Central Index Key	1,370,702
Current Fiscal Year End Date	--12-30
Entity Filer Category	Accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity common stock, shares outstanding		37,394,790
Entity Emerging Growth Company	true
Entity Small Business	false
Entity Ex Transition Period	true

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Current assets
Cash and cash equivalents	$ 34,559	$ 24,432
Marketable securities	97,471	94,195
Accounts receivable	20,081	26,786
Inventory	21,578	12,662
Prepaid expenses and other current assets	6,512	2,744
Total current assets	180,201	160,819
Deferred tax assets	37,443	35,422
Property and equipment, net	13,418	12,511
Intangible and other assets, net	3,571	3,952
Total assets	234,633	212,704
Current liabilities
Accounts payable	10,255	3,754
Accrued liabilities and other current liabilities	23,220	21,065
Long-term debt, current portion	0	3,943
Total current liabilities	33,475	28,762
Other long-term liabilities	2,670	3,339
Total liabilities	36,145	32,101
Commitments and contingencies (see Note 7)
Stockholders’ equity
Common stock: $0.0001 par value, 1,000,000,000 shares authorized at September 30, 2018 and December 31, 2017, 37,346,536 and 35,528,880 shares issued and outstanding at September 30, 2018 and December 31, 2017, respectively	3	3
Additional paid-in capital	324,931	308,023
Accumulated other comprehensive loss	(894)	(207)
Accumulated deficit	(125,552)	(127,216)
Total stockholders’ equity	198,488	180,603
Total liabilities and stockholders’ equity	$ 234,633	$ 212,704

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Common stock, par value (usd per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	1,000,000,000	1,000,000,000
Common stock, shares issued (in shares)	37,346,536	35,528,880
Common stock, shares outstanding (in shares)	37,346,536	35,528,880

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Oct. 01, 2017	Sep. 30, 2018	Oct. 01, 2017
Income Statement [Abstract]
Revenue	$ 59,349	$ 50,108	$ 157,893	$ 135,084
Cost of revenue	29,859	25,591	79,774	68,212
Gross profit	29,490	24,517	78,119	66,872
Operating expenses:
Research and development	17,783	15,011	52,468	43,699
Sales and marketing	3,833	3,363	12,307	9,553
General and administrative	4,886	3,735	13,602	11,231
Total operating expenses	26,502	22,109	78,377	64,483
Income (loss) from operations	2,988	2,408	(258)	2,389
Interest expense	0	(103)	0	(442)
Other income, net	243	223	807	610
Income before income taxes	3,231	2,528	549	2,557
Benefit (provision) for income taxes	648	274	1,115	(470)
Net income	$ 3,879	$ 2,802	$ 1,664	$ 2,087
Net income per share:
Basic (usd per share)	$ 0.10	$ 0.08	$ 0.05	$ 0.06
Diluted (usd per share)	$ 0.10	$ 0.07	$ 0.04	$ 0.05
Weighted average shares used to compute basic and diluted net income per share:
Basic (in shares)	37,070	34,734	36,476	33,907
Diluted (in shares)	40,026	38,525	39,425	38,419

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Oct. 01, 2017	Sep. 30, 2018	Oct. 01, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 3,879	$ 2,802	$ 1,664	$ 2,087
Other comprehensive gain (loss), net of tax:
Unrealized gains (losses) on available-for-sale marketable securities	105	12	(22)	(20)
Unrealized losses on derivative instruments	(247)	0	(664)	0
Other comprehensive gain (loss), net of tax	(142)	12	(686)	(20)
Comprehensive income	$ 3,737	$ 2,814	$ 978	$ 2,067

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Oct. 01, 2017
Cash flows from operating activities
Net income	$ 1,664	$ 2,087
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	3,467	1,566
Stock-based compensation expense	12,923	7,447
Deferred income taxes	(1,821)	0
Other	705	347
Changes in assets and liabilities:
Accounts receivable	6,705	(8,340)
Inventory	(8,916)	(7,880)
Prepaid expenses and other current assets	(3,768)	(22)
Deferred rent and other assets	159	(790)
Accounts payable	6,498	5,119
Accrued liabilities and other current liabilities	2,075	14,660
Net cash provided by operating activities	19,691	14,194
Cash flows from investing activities
Purchase of property and equipment	(3,962)	(6,961)
Purchase of long-term investment	(590)	0
Purchase of marketable securities	(47,917)	(104,044)
Proceeds from sales of marketable securities	0	3,670
Maturities of marketable securities	44,259	12,239
Net cash used in investing activities	(8,210)	(95,096)
Cash flows from financing activities
Proceeds from issuance of common stock, net	6,091	5,083
Payments of taxes withheld for vested stock awards	(2,428)	(626)
Payments related to intangible asset purchase	(815)	0
Repayments of long-term debt	(3,943)	(1,756)
Net cash (used in) provided by financing activities	(1,095)	2,701
Effect of exchange rates on cash and cash equivalents	(259)	0
Net increase (decrease) in cash and cash equivalents	10,127	(78,201)
Beginning of period	24,432	117,045
End of period	34,559	38,844
Supplemental disclosure of cash flow information
Interest paid during the period	0	342
Income taxes paid during the period	$ 180	$ 746

The Company and Summary of Sign

The Company and Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
The Company and Summary of Significant Accounting Policies	The Company and Summary of Significant Accounting Policies Quantenna Communications, Inc. (the “Company”) was incorporated in the State of Delaware on November 28, 2005. The Company designs, develops and markets advanced high-speed wireless communication solutions enabling wireless local area networking. The Company’s solutions are designed to deliver leading-edge Wi-Fi performance to support an increasing number of connected devices accessing a rapidly growing pool of digital content. The Company applies its wireless systems and software expertise with high-performance radio frequency, mixed-signal and digital semiconductor design skills to provide highly integrated Wi-Fi solutions to its customers. Reporting Calendar The Company prepares financial statements on a 52- or 53-week fiscal year that ends on the Sunday closest to December 31. Fiscal 2018 will have 52 weeks and fiscal 2017 had 52 weeks. In a 52-week year, each fiscal quarter consists of 13 weeks. Fiscal 2018 will end on December 30, 2018 . Unaudited Interim Financial Information The accompanying interim condensed consolidated financial statements and related disclosures are unaudited and in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for a fair statement of the results of operations for the periods presented. The year-end condensed consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by accounting principles generally accepted in the United States of America (“US GAAP”). The condensed consolidated results of operations for the three and nine months ended September 30, 2018 are not necessarily indicative of the results to be expected for the full year or for any other future year or interim period. The accompanying condensed consolidated financial statements should be read in conjunction with the audited financial statements and the related notes thereto included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2017 filed with the Securities and Exchange Commission (the “SEC”) on February 28, 2018 (“ 2017 Annual Report on Form 10-K”). Use of Estimates Preparation of financial statements in conformity with US 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 financial statements and reported amounts of revenue and expenses during the reporting periods covered by the financial statements and accompanying notes. Among the significant estimates affecting the financial statements are those related to inventories, revenue recognition, stock-based compensation and income taxes. Actual results could differ from those estimates. Principles of Consolidation The condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany transactions and balances have been eliminated in consolidation. Significant Accounting Policies During the three and nine months ended September 30, 2018 , there have been no changes in our significant accounting policies as described in the 2017 Annual Report on Form 10-K, except as discussed below: Revenue Recognition The Company adopted Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2014-09, Revenue from Contracts with Customers (Topic 606) on January 1, 2018 which resulted in a change to our revenue policy relating to customer rebate arrangements. Revenue is recognized when control of the promised goods or services is transferred to customers, in an amount that reflects the consideration the Company expects to be entitled to in exchange for those goods or services. The Company adopted Accounting Standard Codification (“ASC”) Topic 606 (“ASC Topic 606”) as of January 1, 2018 using the modified retrospective transition method. Based on the evaluation of its current contracts and revenue streams under the new standard, the Company identified a change in accounting relating to customer rebate arrangements. Under the new standard, the Company is required to account for customer rebate arrangements as variable consideration which requires an estimate of the variable consideration to be made when revenue is recognized. In order to estimate this amount, the Company used historical data to determine an estimate of breakage which was applied to the amount of customer rebate due under its contractual arrangements. The cumulative effect upon adoption of ASC Topic 606 was not material and did not have a material impact on the Company’s consolidated financial position or results of operations. The impact of the estimate of breakage for the three and nine months ended September 30, 2018 of $0.2 million and $0.6 million , respectively, recorded as a result of applying the new revenue standard is not considered material to revenue or any other affected financial statement line items. The following table sets forth the Company’s revenue by geographic region, based on ship-to destinations (in thousands): Three Months Ended Three Months Ended September 30, 2018 October 1, 2017 Amount % of revenue Amount % of revenue Asia-Pacific $ 54,832 92 % $ 46,864 94 % Europe, Middle East and Africa 4,409 8 3,051 6 Americas 108 — 193 — Total $ 59,349 100 % $ 50,108 100 % Nine Months Ended Nine Months Ended September 30, 2018 October 1, 2017 Amount % of revenue Amount % of revenue Asia-Pacific $ 144,528 92 % $ 125,040 93 % Europe, Middle East and Africa 13,221 8 9,789 7 Americas 144 — 255 — Total $ 157,893 100 % $ 135,084 100 % Derivative Financial Instruments The Company uses derivative instruments to manage its exposure to changes in foreign currency exchange rates from forecasted cash flows associated with the operational expenses of its foreign subsidiaries. Derivative instruments are measured at their fair values and recognized as either assets or liabilities. The Company’s derivative forward contracts are designated as cash-flow hedges and their effectiveness is measured by comparing the cumulative forward-rate changes in the fair value of the hedge contract with the cumulative forward-rate change in the forecasted cash flows of the hedged item. Refer to Note 2 to the condensed consolidated financial statements, Recent Accounting Pronouncements , and to Note 6 to the condensed consolidated financial statements, Derivative Instruments , for further details. Reclassifications Reclassifications of certain prior period amounts in the condensed consolidated financial statements have been made to conform to the current period presentation.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements On February 14, 2018, the FASB released ASU 2018-02, Income Statement – Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income. The guidance allows a company to elect to reclassify from accumulated other comprehensive income (“AOCI”) to retained earnings the stranded tax effects from the adoption of the newly enacted federal corporate tax rate as a result of the 2017 Tax Cuts and Jobs Act (the “Tax Act”). The amount of the reclassification is calculated as the difference between the amount initially charged to other comprehensive income at the time of the previously enacted tax rate that remains in AOCI and the amount that would have been charged using the newly enacted tax rate, excluding any valuation allowance previously charged to income. ASU 2018-02 is effective for fiscal years beginning after December 15, 2018 and interim periods within those fiscal years, with early adoption permitted. The Company decided to early adopt ASU 2018-02 during the three months ended September 30, 2018 with no material impact to our condensed consolidated financial statements as a result of this adoption. In August 2017, the FASB issued ASU 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities . The new standard is intended to improve and simplify accounting rules around hedge accounting. The new standard refines and expands hedge accounting for both financial (e.g., foreign currency) and commodity risks. Its provisions create more transparency around how economic results are presented, both on the face of the financial statements and in the footnotes, for investors and analysts. The new standard takes effect for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. Early adoption is permitted in any interim period or fiscal years before the effective date of the standard. The Company early-adopted ASU 2017-12 during the second quarter of fiscal 2018 when it commenced its hedging activities and which did not result in any adjustment to the Company’s condensed consolidated financial statements as of the beginning of the second quarter of fiscal 2018. Refer to Note 6 to the condensed consolidated financial statements, Derivative Instruments , for further details. In February 2016, the FASB issued ASU 2016-02, Leases (“ASC 842”), which sets out the principles for the recognition, measurement, presentation and disclosure of leases for both parties to a contract (i.e., lessees and lessors). The new standard requires lessees to apply a dual approach, classifying leases as either finance or operating leases based on the principle of whether or not the lease is effectively a financed purchase by the lessee. This classification will determine whether lease expense is recognized based on an effective interest method or on a straight-line basis over the term of the lease, respectively. A lessee is also required to record a right-of-use asset and a lease liability for all leases with a term of greater than twelve months regardless of their classification. Leases with a term of twelve months or less will be accounted for similar to existing guidance for operating leases today. ASC 842 supersedes the previous leases standard, ASC 840 Leases . The standard is effective on January 1, 2019, with early adoption permitted. The Company is evaluating the effect that the adoption of ASC 842 will have on its financial statements. The Company currently expects that most of its operating lease commitments will be subject to the new standard and recognized as right-of-use assets and operating lease liabilities upon the adoption of ASC 842, which will increase the total assets and total liabilities that it reports relative to such amounts prior to adoption.

Earnings Per Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share The following table summarizes the Company’s computation of basic and diluted net loss per share: Three Months Ended Nine Months Ended September 30, October 1, September 30, October 1, (in thousands, except per share data) Net income $ 3,879 $ 2,802 $ 1,664 $ 2,087 Weighted-average shares outstanding - basic 37,070 34,734 36,476 33,907 Dilutive effect of stock options, ESPP and RSUs 2,956 3,791 2,949 4,512 Weighted average shares outstanding - diluted 40,026 38,525 39,425 38,419 Net income per share: Basic $ 0.10 $ 0.08 $ 0.05 $ 0.06 Diluted $ 0.10 $ 0.07 $ 0.04 $ 0.05 The following potentially dilutive securities outstanding at the end of the periods have been excluded from the computation of diluted shares outstanding as the effect would have been anti-dilutive: Three Months Ended Nine Months Ended September 30, October 1, September 30, October 1, (in thousands) Shares available for Employee Stock Purchase Plan (ESPP) 16 — 8 — Restricted Stock Units (RSUs) 47 104 172 881 Options to purchase common stock 1,289 672 1,436 672 Total 1,352 776 1,616 1,553

Balance Sheets Components

Balance Sheets Components	9 Months Ended
	Sep. 30, 2018
Balance Sheets Components [Abstract]
Balance Sheets Components	Balance Sheets Components Marketable Securities Marketable securities at September 30, 2018 consisted of the following: Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (in thousands) Corporate debt securities $ 91,438 $ 6 $ (291 ) $ 91,153 Government debt securities 6,339 — (21 ) 6,318 $ 97,777 $ 6 $ (312 ) $ 97,471 The contractual maturities of marketable securities as of September 30, 2018 were as follows: Amortized Cost Fair Value (in thousands) Due in one year or less $ 79,848 $ 79,668 Due after one year to five years 17,929 17,803 $ 97,777 $ 97,471 Marketable securities as of December 31, 2017 consisted of the following: Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (in thousands) Corporate debt securities $ 83,570 $ 7 $ (250 ) $ 83,327 Government debt securities 10,889 — (21 ) 10,868 $ 94,459 $ 7 $ (271 ) $ 94,195 The contractual maturities of marketable securities as of December 31, 2017 were as follows: Amortized Cost Fair Value (in thousands) Due in one year or less $ 49,201 $ 49,144 Due after one year to five years 45,258 45,051 $ 94,459 $ 94,195 Property and Equipment, Net Property and equipment, net consisted of the following: September 30, December 31, (in thousands) Computer and lab equipment $ 16,950 $ 14,295 Computer software 968 795 Furniture and fixtures 1,739 1,589 Leasehold improvements 4,363 3,977 Sub-total 24,020 20,656 Accumulated depreciation and amortization (10,602 ) (8,145 ) Property and equipment, net $ 13,418 $ 12,511 Depreciation and amortization expense related to property and equipment was $0.9 million and $0.5 million , respectively, for the three months ended September 30, 2018 and October 1, 2017 , and $2.7 million and $1.6 million , respectively, for the nine months ended September 30, 2018 and October 1, 2017 . Inventory Inventory consisted of the following: September 30, December 31, (in thousands) Raw materials $ 7,481 $ 5,812 Work in progress 2,121 1,069 Finished goods 11,976 5,781 $ 21,578 $ 12,662 Accrued Liabilities and Other Current Liabilities Accrued liabilities and other current liabilities consisted of the following: September 30, December 31, (in thousands) Accrued customer rebates $ 9,044 $ 8,710 Accrued payroll and related benefits 5,683 3,411 Accrued expenses 2,688 4,507 Accrual for inventory purchases 980 2,124 ESPP employee contributions 2,261 706 Other 2,564 1,607 $ 23,220 $ 21,065

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The Company determines fair value measurements used in its consolidated financial statements based upon the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The fair value hierarchy distinguishes between (i) market participant assumptions developed based on market data obtained from independent sources (observable inputs) and (ii) an entity’s own assumptions about market participant assumptions developed based on the best information available in the circumstances (unobservable inputs). The fair value hierarchy consists of three broad levels, which gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1) and the lowest priority to unobservable inputs (Level 3). The three levels of the fair value hierarchy are described below: Level 1: Valuations based on quoted prices in active markets for identical assets or liabilities that the entity has the ability to access. Level 2: Valuations based on quoted prices for similar assets or liabilities, quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable data for substantially the full term of the assets or liabilities. Level 3: Valuations based on inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The Company obtains the fair value of our Level 1 investments in money market funds, at the expected market price. These investments are expected to maintain a net asset value of $1 per share. The Company determines the fair value of our Level 2 financial instruments from third-party asset managers, custodian banks, and the accounting service providers. The Company classifies financial instruments in Level 3 of the fair value hierarchy when there is reliance on at least one significant unobservable input to the valuation model. In addition to these unobservable inputs, the valuation models for Level 3 financial instruments typically also rely on a number of inputs that are readily observable, either directly or indirectly. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires management to make judgments and consider factors specific to the asset or liability. There were no assets or liabilities in Level 3 of the fair value hierarchy and there were no transfers between Level 1 and Level 2 categories during the year ended any of the periods presented. The Company utilizes the market approach to measure the fair value of our fixed income securities. The market approach is a valuation technique that uses prices and other relevant information generated by market transactions involving identical or comparable assets or liabilities. The fair value of our fixed income securities is obtained using readily-available market prices from a variety of industry standard data providers, large financial institutions and other third-party sources for the identical underlying securities. Assets and Liabilities Measured at Fair Value on a Recurring Basis The Company measures and reports certain assets at fair value on a recurring basis as shown below except for cash held at banks that are measured at historical cost and which are therefore not included in the tables below. Fair Value as of September 30, 2018 Level 1 Level 2 Level 3 Total Assets: (in thousands) Cash equivalents: Money market funds $ 1,254 $ — $ — $ 1,254 Commercial paper — 2,499 — 2,499 Government debt securities — 648 — 648 Total cash equivalents 1,254 3,147 — 4,401 Marketable Securities: — Corporate debt securities — 91,153 — 91,153 Government debt securities — 6,318 — 6,318 Total marketable securities — 97,471 — 97,471 Total cash equivalents and marketable securities $ 1,254 $ 100,618 $ — $ 101,872 Fair Value as of December 31, 2017 Level 1 Level 2 Level 3 Total Assets: (in thousands) Cash equivalents: Money market funds $ 4,398 $ — $ — $ 4,398 Corporate debt securities — 2,000 — 2,000 Total cash equivalents 4,398 2,000 — 6,398 Marketable Securities: — Corporate debt securities — 83,329 — 83,329 Government debt securities — 10,866 — 10,866 Total marketable securities — 94,195 — 94,195 Total cash equivalents and marketable securities $ 4,398 $ 96,195 $ — $ 100,593 The Level 1 assets consist of money market funds. The Level 2 assets consist of available-for-sale investment portfolio, which are valued utilizing a market approach. Foreign currency derivative forward contracts are measured at fair value based on market-based observable inputs including currency exchange spot and forward rates, interest rates, and credit-risk spreads, and are classified at Level 2 of the fair value hierarchy. Total notional and net fair values for foreign exchange derivative contracts designated as hedging instruments as of September 30, 2018 were as follows: Derivative Assets* Derivative Liabilities* Notional Amount Fair Value Notional Amount Fair Value (in thousands) Current assets $ 309 $ 3 Current liabilities $ 18,021 $ 768 Non-current assets** 1,967 14 Non-current liabilities** 3,925 93 Total foreign exchange contracts $ 2,276 $ 17 Total foreign exchange contracts $ 21,946 $ 861 * The Company recorded a net derivative liability of $0.8 million as of September 30, 2018. There were no derivative assets or liabilities recorded for the comparative periods in fiscal 2017. ** Non-current derivative assets and liabilities were discounted at the prevailing risk-free interest rate. Common Stock Warrants There were no common stock warrants exercised during the three months ended September 30, 2018 . During the nine months ended September 30, 2018 , the remaining 58,006 common stock warrants of those originally issued in September 2015 were exercised at $2.50 per share. There were no outstanding common stock warrants as of September 30, 2018 . As of December 31, 2017 , warrants issued and outstanding were as follows: Date of Issuance Number of Warrants Exercise Price Expiration Date Common stock warrants September 2015 83,006 $ 2.50 February 2019

Derivative Financial Instrument

Derivative Financial Instruments	9 Months Ended
	Sep. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	Derivative Financial Instruments The Company uses foreign currency forward contracts to reduce the earnings impact that exchange rate fluctuations have on operating expenses denominated in currencies other than the U.S. dollar. For accounting purposes, foreign currency forward contracts are designated as hedging instruments and, accordingly, the Company will record the fair value of the effective portion of these contracts as of the end of its’ reporting period in its’ condensed consolidated balance sheets (as an asset or a liability) with changes in fair value recorded within “ Accumulated other comprehensive loss ” under “Total stockholders’ equity”. The fair values of the derivative financial instruments are combined together on the balance sheet whenever there is a master netting arrangement in place. The changes in fair value will remain in “ Accumulated other comprehensive loss ” until the costs are recognized, at which time the Company will reclassify the cumulative change of fair value relating to the hedges proportionately into the respective line items on the condensed consolidated income statements. Any changes in fair value of the ineffective portion of the forward contracts will be recognized immediately in the Company’s consolidated income statement under “ Other income, net ”. In concurrence with the implementation of its hedging program, the Company early-adopted the provisions of ASU 2017-12 as of the beginning of the second quarter of fiscal 2018 on a prospective basis. The early-adoption of ASU 2017-12 did not result in any adjustment to the Company’s consolidated financial statements as of the beginning of the second quarter of fiscal 2018 as the Company did not enter into any hedge accounting activities in prior reporting periods. The effects of derivative instruments and hedging activities on the condensed consolidated statement of operations and its effect on the condensed consolidated statement of comprehensive loss from changes in fair value for the three and nine months ended September 30, 2018 was as follows: Location and Amount of Loss Recognized for Hedging Activities: Condensed Consolidated Statement of Operations Condensed Consolidated Statement of Comprehensive Loss (pre-tax) Research and Development Sales and Marketing General and Administrative Total (in thousands) Total expense from foreign currency hedging $ 189 $ 39 $ 13 $ 241 $ 314 Effects of foreign currency cashflow hedging: Loss reclassified from condensed consolidated statement of comprehensive loss $ (189 ) (39 ) (13 ) (241 ) $ 241 Loss recognized in condensed consolidated statement of comprehensive loss $ — $ — $ — $ — $ 555 The Company did not enter into any hedging activities for the comparative periods in fiscal 2017.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Leases The Company conducts its operations using leased office facilities in various locations. The following is a schedule of future minimum lease payments under operating leases as of September 30, 2018 (in thousands): 2018 (remaining three months) $ 747 2019 2,819 2020 2,344 2021 1,900 2022 and beyond 4,055 Total minimum lease payments $ 11,865 The Company leases office space under arrangements expiring through 2026. Rent expense for the three months ended September 30, 2018 and October 1, 2017 was $0.7 million and $0.4 million , respectively, and $2.2 million and $1.2 million , respectively, for the nine months ended September 30, 2018 and October 1, 2017 . Purchase Commitments The Company has purchase obligations of $16.9 million that are based on outstanding purchase orders as of September 30, 2018 , related to the fabrication of certain wafers for which production has started. These purchase orders are cancellable at any time, provided that the Company pays all costs incurred through the cancellation date. Historically, the Company has rarely canceled these agreements once production has started. The Company did not otherwise have any outstanding non-cancellable purchase obligations as of September 30, 2018 . Indemnification In connection with the sale of its semiconductor products, the Company executes standard software license agreements allowing customers to use its firmware. Under the indemnification clauses of these license agreements, the Company agrees to defend the licensee against third-party claims asserting infringement by the Company’s products of certain intellectual property rights, which may include patents, copyrights, trademarks or trade secrets, and to pay any judgments entered on such claims against the licensee, subject to certain restrictions and limitations. The Company has never incurred significant expense defending its licensees against third-party claims. Further, the Company has never incurred significant expense under its standard product or services performance warranties. As a result, the Company believes the estimated fair value of these agreements is minimal. Accordingly, the Company has no liabilities recorded for these agreements at September 30, 2018 . Commitments In April 2012, an agreement was entered into with Joint Stock Company “RUSNANO” (“RUSNANO”) (formerly Open Joint Stock Company “RUSNANO”), which required the Company to form a wholly-owned subsidiary in the Russian Federation and to provide funding to the subsidiary in the three years following April 16, 2012. This wholly-owned subsidiary performs research and development activities for the Company. Funding means cash transfers to the subsidiary for equity investments, reimbursements of subsidiary operating expenses and Company expenses related to the subsidiary. RUSNANO also requires participation in subsidiary financial decisions. In July 2014, the Company entered into an amended and restated letter agreement with RUSNANO pursuant to which the Company agreed, among other matters, to operate and fund its Russian operations in an aggregate amount of $13.0 million over six annual periods beginning on December 31, 2014. The annual funding requirements in period one to period six are $2.2 million , $1.7 million , $2.0 million , $2.2 million , $2.4 million , and $2.5 million , respectively. In the event that the Company fails to meet its funding obligations for any period, it will be required to pay RUSNANO a penalty fee of 10% on 80% of the difference between the funding obligation and the actual funding for that period, subject to a cure period of one calendar quarter after the applicable period funding deadline. As of September 30, 2018 , the Company had met the minimum funding requirements and no penalty had been incurred. As of September 30, 2018 , the Company’s non-cancellable obligations for its definite long-lived intangible assets which are comprised of software licenses were approximately $3.0 million , of which $0.3 million is due payable in fiscal 2018 and $2.7 million is due payable within the subsequent two years. Legal Matters From time to time, the Company is a party to litigation and subject to claims incident to the ordinary course of business, including intellectual property claims, labor and employment claims, breach of contract claims, and other matters. Significant judgment is required when we assess the likelihood of any adverse judgments or outcomes to a potential claim or legal proceeding, as well as potential ranges of probable losses, and when the outcomes of the claims or proceedings are probable and reasonably estimable. Because of uncertainties related to these matters, we base our estimates on the information available at the time. As additional information becomes available, we reassess the potential liability related to pending claims and litigation, and may revise our estimates. Any revisions in the estimates of potential liabilities could have a material impact on the Company’s results of operations, financial position, and cash flows.

Long-term Debt

Long-term Debt	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Long-term Debt	Long-term Debt Loan and Security Agreement The Company’s Amended and Restated Loan and Security Agreement with Silicon Valley Bank (“SVB”) (the “SVB Loan and Security Agreement”) includes (i) term loans, (ii) a revolving line of credit, and (iii) a mezzanine loan. The mezzanine loan was canceled upon its expiration in fiscal 2017 and the revolving line of credit expired in May 2018. On December 31, 2017, the Company sought to extinguish its term loans under the SVB Loan and Security Agreement of which approximately $3.9 million (including interest and early termination fees) remained outstanding. The Company reclassified the final $3.9 million payment on December 31, 2017 to “Long-term debt, current portion” in its condensed consolidated balance sheet as of that date. The payment for the extinguishment of the term loans was processed on January 2, 2018.

Stockholders_ Equity

Stockholders’ Equity	9 Months Ended
	Sep. 30, 2018
Equity [Abstract]
Stockholders' Equity	Stockholders’ Equity Common Stock The Company’s Certificate of Incorporation, as amended, authorizes the Company to issue 1,000,000,000 shares of $0.0001 par value common stock. Each share of common stock is entitled to one vote. The holders of common stock are also entitled to receive dividends whenever funds are legally available and when and if declared by the board of directors. The Company has never declared any dividends. The Company had reserved shares of common stock for issuance, on an as-converted basis, as follows: September 30, 2018 Options issued and outstanding 4,562,312 RSUs issued and outstanding 1,861,257 Shares available for ESPP 1,418,697 Shares available for future stock awards 2,580,091 10,422,357 During the nine months ended September 30, 2018 , the Company granted 1,489,046 restricted stock units (“RSUs”) and 666,250 options to employees. During the nine months ended October 1, 2017 , the Company granted 1,041,629 RSUs and 516,750 options to employees. Options Subject to Repurchase The Company has a right of repurchase with respect to unvested shares issued upon early exercise of options at an amount equal to the lower of (i) the exercise price of each restricted share being repurchased and (ii) the fair market value of such restricted share at the time the Company’s right of repurchase is exercised. The Company’s right to repurchase these shares lapses as to 1/36th of the total number of shares originally granted per month for 36 months . During the three months ended September 30, 2018 , 22,000 unvested shares which were early-exercised were repurchased by the Company. As of September 30, 2018 , there were no more unvested shares subject to the Company’s right of repurchase.

Stock-based Compensation

Stock-based Compensation	9 Months Ended
	Sep. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-based Compensation	Stock-based Compensation Total stock-based compensation expense for employees and non-employees recognized in the condensed consolidated statements of operations was as follows: Three Months Ended Nine Months Ended September 30, October 1, September 30, October 1, (in thousands) Cost of revenue $ 50 $ 38 $ 146 $ 123 Research and development 2,248 1,367 7,170 3,986 Sales and marketing 541 416 2,118 1,179 General and administrative 1,163 948 3,489 2,159 Total stock-based compensation expense $ 4,002 $ 2,769 $ 12,923 $ 7,447 The above stock-based compensation expense related to the following equity-based awards: Three Months Ended Nine Months Ended September 30, October 1, September 30, October 1, (in thousands) Stock options $ 1,010 $ 858 $ 3,186 $ 2,539 RSU awards 2,753 1,603 8,269 3,553 ESPP shares 239 308 1,468 1,355 Total stock-based compensation expense $ 4,002 $ 2,769 $ 12,923 $ 7,447

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company recorded an income tax benefit of $0.6 million and $0.3 million , for the three months ended September 30, 2018 and October 1, 2017 , respectively, and an income tax benefit of $1.1 million and an income tax provision of $0.5 million for the nine months ended September 30, 2018 and October 1, 2017 , respectively. The income tax benefit consists primarily of discrete excess stock based tax benefits. The provision for income taxes consists primarily of income taxes in the foreign jurisdictions in which we conduct business. In the fourth quarter of fiscal 2017, management concluded that the valuation allowance for the Company's U.S. federal and state (with the exception of California) deferred tax assets was no longer needed primarily due to the emergence from cumulative losses over the previous three years. As of September 30, 2018 , based on the available objective evidence, management still believes it is more likely than not that the net deferred tax assets will be realized for federal and state purposes. We will continue to maintain a valuation allowance in those jurisdictions deemed necessary until sufficient positive evidence exists to support reversal. Such assessment may change in the future as further evidence becomes available. On December 22, 2017, the U.S. government enacted comprehensive tax legislation commonly referred to as the Tax Act. The Tax Act makes broad and complex changes to the U.S. tax federal and state tax laws that affected 2017, the current year and onwards, including, but not limited to, a reduction of the U.S. federal corporate tax rate from as high as 35% to 21% , a general elimination of U.S. federal income taxes on dividends from foreign subsidiaries, net operating loss deduction limitations, and 100% disallowance of entertainment expense. The Tax Act adds new provisions relating to “foreign derived intangible income” (“FDII”) and “global intangible low-taxed income” (“GILTI”). The Company has completed an analysis for FDII and GILTI and due to the forecasted results of the Company, there is currently no impact on the provision. On December 22, 2017, the SEC staff issued Staff Accounting Bulletin No. 118 (“SAB 118”) which provides guidance on accounting for the tax effects of the Tax Act. SAB 118 provides a measurement period that should not extend beyond one year from the Tax Act enactment date for companies to complete the accounting under ASC 740, Income Taxes (“ASC 740”) for the year ended December 31, 2017. In accordance with SAB 118, a company must reflect the income tax effects of those aspects of the Tax Act for which the accounting under ASC 740 is complete. The Company is still within the measurement period as of the third quarter of fiscal 2018 and no further conclusions have been made, as the Company reviews the law change and the impact to the Company. Under Section 382 of the Internal Revenue Code of 1986, as amended (the “Code”), our ability to utilize net operating loss carry-forwards (“NOLs”) or other tax attributes such as research tax credits, in any taxable year may be limited if we experience, or have experienced, an “ownership change.” A Section 382 “ownership change” generally occurs if one or more stockholders or groups of stockholders, who own at least 5% of our stock, increase their ownership by more than 50 percentage points over their lowest ownership percentage within a rolling three-year period. Similar rules may apply under state tax laws. We have completed an analysis under Section 382 of the Code through December 31, 2017 and determined that there was no significant limitation to the utilization of NOL or tax credit carryforwards before they expire. We are in the process of updating the study through the current year and will update for any significant limitations to the utilization of NOL or tax credit carryforwards in the current year upon completion of the study.

Employee Benefit Plans

Employee Benefit Plans	9 Months Ended
	Sep. 30, 2018
Retirement Benefits [Abstract]
Employee Benefit Plans	Employee Benefit Plans Defined Contribution Plan The Company adopted a 401(k) Plan that qualifies as a deferred compensation arrangement under Section 401 of the Code. Under the 401(k) Plan, participating employees may defer a portion of their pretax earnings not to exceed the maximum amount allowable. The 401(k) Plan permits the Company to make matching contributions and profit sharing contributions to eligible participants. The Company has made matching contributions of $0.4 million for the nine months ended September 30, 2018 .

Related Party transactions

Related Party transactions	9 Months Ended
	Sep. 30, 2018
Related Party Transactions [Abstract]
Related Party transactions	Related Party Transactions Purchases from Cadence Design Systems, Inc. Lip-Bu Tan, a member of the Company’s board of directors since June 2015, resigned from the board in accordance with his previously announced intentions, effective June 5, 2018 in connection with the Company’s Annual Meeting of Stockholders. As a result, Mr. Tan ceased to be a related party to the Company during the second quarter of fiscal 2018 which ended on July 1, 2018. Mr. Tan is the President and Chief Executive Officer of Cadence Design Systems, Inc. (“Cadence”), an electronic design automation software and engineering services company. Since 2012, the Company has paid licensing fees for digital and analog layout tools and simulation tools from Cadence in the ordinary course of business. In fiscal 2017, the Company entered into a software license contract with Cadence for the use of various EDA software tools used for its research and development efforts. The Company classified the software licenses as definite long-lived intangible assets in its condensed consolidated balance sheets amounting to approximately $2.4 million as of July 1, 2018, net of accumulated amortization of approximately $0.8 million . Under the terms of this arrangement, the Company amortized fees, in its condensed consolidated statements of operations, of approximately $0.5 million during the six months ended July 1, 2018, and approximately $2.0 million and $3.7 million during the three and nine months ended October 1, 2017, respectively. During the six months ended July 1, 2018, the Company engaged Cadence for design and development services related to integrated circuits amounting to approximately $1.8 million .

The Company and Summary of Si_2

The Company and Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Reporting Calendar	Reporting Calendar The Company prepares financial statements on a 52- or 53-week fiscal year that ends on the Sunday closest to December 31. Fiscal 2018 will have 52 weeks and fiscal 2017 had 52 weeks. In a 52-week year, each fiscal quarter consists of 13 weeks.
Use of Estimates	Use of Estimates Preparation of financial statements in conformity with US 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 financial statements and reported amounts of revenue and expenses during the reporting periods covered by the financial statements and accompanying notes. Among the significant estimates affecting the financial statements are those related to inventories, revenue recognition, stock-based compensation and income taxes. Actual results could differ from those estimates.
Principles of Consolidation	Principles of Consolidation The condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany transactions and balances have been eliminated in consolidation.
Revenue Recognition	Revenue Recognition The Company adopted Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2014-09, Revenue from Contracts with Customers (Topic 606) on January 1, 2018 which resulted in a change to our revenue policy relating to customer rebate arrangements. Revenue is recognized when control of the promised goods or services is transferred to customers, in an amount that reflects the consideration the Company expects to be entitled to in exchange for those goods or services. The Company adopted Accounting Standard Codification (“ASC”) Topic 606 (“ASC Topic 606”) as of January 1, 2018 using the modified retrospective transition method. Based on the evaluation of its current contracts and revenue streams under the new standard, the Company identified a change in accounting relating to customer rebate arrangements. Under the new standard, the Company is required to account for customer rebate arrangements as variable consideration which requires an estimate of the variable consideration to be made when revenue is recognized. In order to estimate this amount, the Company used historical data to determine an estimate of breakage which was applied to the amount of customer rebate due under its contractual arrangements. The cumulative effect upon adoption of ASC Topic 606 was not material and did not have a material impact on the Company’s consolidated financial position or results of operations.
Derivative Financial Instruments	Derivative Financial Instruments The Company uses derivative instruments to manage its exposure to changes in foreign currency exchange rates from forecasted cash flows associated with the operational expenses of its foreign subsidiaries. Derivative instruments are measured at their fair values and recognized as either assets or liabilities. The Company’s derivative forward contracts are designated as cash-flow hedges and their effectiveness is measured by comparing the cumulative forward-rate changes in the fair value of the hedge contract with the cumulative forward-rate change in the forecasted cash flows of the hedged item.
Reclassifications	Reclassifications Reclassifications of certain prior period amounts in the condensed consolidated financial statements have been made to conform to the current period presentation.
New Accounting Pronouncements	Recent Accounting Pronouncements On February 14, 2018, the FASB released ASU 2018-02, Income Statement – Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income. The guidance allows a company to elect to reclassify from accumulated other comprehensive income (“AOCI”) to retained earnings the stranded tax effects from the adoption of the newly enacted federal corporate tax rate as a result of the 2017 Tax Cuts and Jobs Act (the “Tax Act”). The amount of the reclassification is calculated as the difference between the amount initially charged to other comprehensive income at the time of the previously enacted tax rate that remains in AOCI and the amount that would have been charged using the newly enacted tax rate, excluding any valuation allowance previously charged to income. ASU 2018-02 is effective for fiscal years beginning after December 15, 2018 and interim periods within those fiscal years, with early adoption permitted. The Company decided to early adopt ASU 2018-02 during the three months ended September 30, 2018 with no material impact to our condensed consolidated financial statements as a result of this adoption. In August 2017, the FASB issued ASU 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities . The new standard is intended to improve and simplify accounting rules around hedge accounting. The new standard refines and expands hedge accounting for both financial (e.g., foreign currency) and commodity risks. Its provisions create more transparency around how economic results are presented, both on the face of the financial statements and in the footnotes, for investors and analysts. The new standard takes effect for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. Early adoption is permitted in any interim period or fiscal years before the effective date of the standard. The Company early-adopted ASU 2017-12 during the second quarter of fiscal 2018 when it commenced its hedging activities and which did not result in any adjustment to the Company’s condensed consolidated financial statements as of the beginning of the second quarter of fiscal 2018. Refer to Note 6 to the condensed consolidated financial statements, Derivative Instruments , for further details. In February 2016, the FASB issued ASU 2016-02, Leases (“ASC 842”), which sets out the principles for the recognition, measurement, presentation and disclosure of leases for both parties to a contract (i.e., lessees and lessors). The new standard requires lessees to apply a dual approach, classifying leases as either finance or operating leases based on the principle of whether or not the lease is effectively a financed purchase by the lessee. This classification will determine whether lease expense is recognized based on an effective interest method or on a straight-line basis over the term of the lease, respectively. A lessee is also required to record a right-of-use asset and a lease liability for all leases with a term of greater than twelve months regardless of their classification. Leases with a term of twelve months or less will be accounted for similar to existing guidance for operating leases today. ASC 842 supersedes the previous leases standard, ASC 840 Leases . The standard is effective on January 1, 2019, with early adoption permitted. The Company is evaluating the effect that the adoption of ASC 842 will have on its financial statements. The Company currently expects that most of its operating lease commitments will be subject to the new standard and recognized as right-of-use assets and operating lease liabilities upon the adoption of ASC 842, which will increase the total assets and total liabilities that it reports relative to such amounts prior to adoption.
Fair Value Measurement	The Company determines fair value measurements used in its consolidated financial statements based upon the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The fair value hierarchy distinguishes between (i) market participant assumptions developed based on market data obtained from independent sources (observable inputs) and (ii) an entity’s own assumptions about market participant assumptions developed based on the best information available in the circumstances (unobservable inputs). The fair value hierarchy consists of three broad levels, which gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1) and the lowest priority to unobservable inputs (Level 3). The three levels of the fair value hierarchy are described below: Level 1: Valuations based on quoted prices in active markets for identical assets or liabilities that the entity has the ability to access. Level 2: Valuations based on quoted prices for similar assets or liabilities, quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable data for substantially the full term of the assets or liabilities. Level 3: Valuations based on inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The Company obtains the fair value of our Level 1 investments in money market funds, at the expected market price. These investments are expected to maintain a net asset value of $1 per share. The Company determines the fair value of our Level 2 financial instruments from third-party asset managers, custodian banks, and the accounting service providers. The Company classifies financial instruments in Level 3 of the fair value hierarchy when there is reliance on at least one significant unobservable input to the valuation model. In addition to these unobservable inputs, the valuation models for Level 3 financial instruments typically also rely on a number of inputs that are readily observable, either directly or indirectly. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires management to make judgments and consider factors specific to the asset or liability. There were no assets or liabilities in Level 3 of the fair value hierarchy and there were no transfers between Level 1 and Level 2 categories during the year ended any of the periods presented. The Company utilizes the market approach to measure the fair value of our fixed income securities. The market approach is a valuation technique that uses prices and other relevant information generated by market transactions involving identical or comparable assets or liabilities. The fair value of our fixed income securities is obtained using readily-available market prices from a variety of industry standard data providers, large financial institutions and other third-party sources for the identical underlying securities.

The Company and Summary of Si_3

The Company and Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Revenue from External Customers by Geographic Areas	The following table sets forth the Company’s revenue by geographic region, based on ship-to destinations (in thousands): Three Months Ended Three Months Ended September 30, 2018 October 1, 2017 Amount % of revenue Amount % of revenue Asia-Pacific $ 54,832 92 % $ 46,864 94 % Europe, Middle East and Africa 4,409 8 3,051 6 Americas 108 — 193 — Total $ 59,349 100 % $ 50,108 100 % Nine Months Ended Nine Months Ended September 30, 2018 October 1, 2017 Amount % of revenue Amount % of revenue Asia-Pacific $ 144,528 92 % $ 125,040 93 % Europe, Middle East and Africa 13,221 8 9,789 7 Americas 144 — 255 — Total $ 157,893 100 % $ 135,084 100 %

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The following table summarizes the Company’s computation of basic and diluted net loss per share: Three Months Ended Nine Months Ended September 30, October 1, September 30, October 1, (in thousands, except per share data) Net income $ 3,879 $ 2,802 $ 1,664 $ 2,087 Weighted-average shares outstanding - basic 37,070 34,734 36,476 33,907 Dilutive effect of stock options, ESPP and RSUs 2,956 3,791 2,949 4,512 Weighted average shares outstanding - diluted 40,026 38,525 39,425 38,419 Net income per share: Basic $ 0.10 $ 0.08 $ 0.05 $ 0.06 Diluted $ 0.10 $ 0.07 $ 0.04 $ 0.05
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	The following potentially dilutive securities outstanding at the end of the periods have been excluded from the computation of diluted shares outstanding as the effect would have been anti-dilutive: Three Months Ended Nine Months Ended September 30, October 1, September 30, October 1, (in thousands) Shares available for Employee Stock Purchase Plan (ESPP) 16 — 8 — Restricted Stock Units (RSUs) 47 104 172 881 Options to purchase common stock 1,289 672 1,436 672 Total 1,352 776 1,616 1,553

Balance Sheets Components (Tabl

Balance Sheets Components (Tables)	9 Months Ended
	Sep. 30, 2018
Balance Sheets Components [Abstract]
Marketable Securities	Marketable securities at September 30, 2018 consisted of the following: Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (in thousands) Corporate debt securities $ 91,438 $ 6 $ (291 ) $ 91,153 Government debt securities 6,339 — (21 ) 6,318 $ 97,777 $ 6 $ (312 ) $ 97,471 The contractual maturities of marketable securities as of September 30, 2018 were as follows: Amortized Cost Fair Value (in thousands) Due in one year or less $ 79,848 $ 79,668 Due after one year to five years 17,929 17,803 $ 97,777 $ 97,471 Marketable securities as of December 31, 2017 consisted of the following: Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (in thousands) Corporate debt securities $ 83,570 $ 7 $ (250 ) $ 83,327 Government debt securities 10,889 — (21 ) 10,868 $ 94,459 $ 7 $ (271 ) $ 94,195 The contractual maturities of marketable securities as of December 31, 2017 were as follows: Amortized Cost Fair Value (in thousands) Due in one year or less $ 49,201 $ 49,144 Due after one year to five years 45,258 45,051 $ 94,459 $ 94,195
Schedule of Property and Equipment	Property and equipment, net consisted of the following: September 30, December 31, (in thousands) Computer and lab equipment $ 16,950 $ 14,295 Computer software 968 795 Furniture and fixtures 1,739 1,589 Leasehold improvements 4,363 3,977 Sub-total 24,020 20,656 Accumulated depreciation and amortization (10,602 ) (8,145 ) Property and equipment, net $ 13,418 $ 12,511
Schedule of Inventory	Inventory consisted of the following: September 30, December 31, (in thousands) Raw materials $ 7,481 $ 5,812 Work in progress 2,121 1,069 Finished goods 11,976 5,781 $ 21,578 $ 12,662
Other Current Liabilities	Accrued liabilities and other current liabilities consisted of the following: September 30, December 31, (in thousands) Accrued customer rebates $ 9,044 $ 8,710 Accrued payroll and related benefits 5,683 3,411 Accrued expenses 2,688 4,507 Accrual for inventory purchases 980 2,124 ESPP employee contributions 2,261 706 Other 2,564 1,607 $ 23,220 $ 21,065
Schedule of Accrued Liabilities	Accrued liabilities and other current liabilities consisted of the following: September 30, December 31, (in thousands) Accrued customer rebates $ 9,044 $ 8,710 Accrued payroll and related benefits 5,683 3,411 Accrued expenses 2,688 4,507 Accrual for inventory purchases 980 2,124 ESPP employee contributions 2,261 706 Other 2,564 1,607 $ 23,220 $ 21,065

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value, Assets Measured on Recurring Basis	The Company measures and reports certain assets at fair value on a recurring basis as shown below except for cash held at banks that are measured at historical cost and which are therefore not included in the tables below. Fair Value as of September 30, 2018 Level 1 Level 2 Level 3 Total Assets: (in thousands) Cash equivalents: Money market funds $ 1,254 $ — $ — $ 1,254 Commercial paper — 2,499 — 2,499 Government debt securities — 648 — 648 Total cash equivalents 1,254 3,147 — 4,401 Marketable Securities: — Corporate debt securities — 91,153 — 91,153 Government debt securities — 6,318 — 6,318 Total marketable securities — 97,471 — 97,471 Total cash equivalents and marketable securities $ 1,254 $ 100,618 $ — $ 101,872 Fair Value as of December 31, 2017 Level 1 Level 2 Level 3 Total Assets: (in thousands) Cash equivalents: Money market funds $ 4,398 $ — $ — $ 4,398 Corporate debt securities — 2,000 — 2,000 Total cash equivalents 4,398 2,000 — 6,398 Marketable Securities: — Corporate debt securities — 83,329 — 83,329 Government debt securities — 10,866 — 10,866 Total marketable securities — 94,195 — 94,195 Total cash equivalents and marketable securities $ 4,398 $ 96,195 $ — $ 100,593
Schedule of derivative instruments in statement of financial position	Total notional and net fair values for foreign exchange derivative contracts designated as hedging instruments as of September 30, 2018 were as follows: Derivative Assets* Derivative Liabilities* Notional Amount Fair Value Notional Amount Fair Value (in thousands) Current assets $ 309 $ 3 Current liabilities $ 18,021 $ 768 Non-current assets** 1,967 14 Non-current liabilities** 3,925 93 Total foreign exchange contracts $ 2,276 $ 17 Total foreign exchange contracts $ 21,946 $ 861 * The Company recorded a net derivative liability of $0.8 million as of September 30, 2018. There were no derivative assets or liabilities recorded for the comparative periods in fiscal 2017. ** Non-current derivative assets and liabilities were discounted at the prevailing risk-free interest rate.
Schedule of Warrants	As of December 31, 2017 , warrants issued and outstanding were as follows: Date of Issuance Number of Warrants Exercise Price Expiration Date Common stock warrants September 2015 83,006 $ 2.50 February 2019

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of derivative gain (loss)	The effects of derivative instruments and hedging activities on the condensed consolidated statement of operations and its effect on the condensed consolidated statement of comprehensive loss from changes in fair value for the three and nine months ended September 30, 2018 was as follows: Location and Amount of Loss Recognized for Hedging Activities: Condensed Consolidated Statement of Operations Condensed Consolidated Statement of Comprehensive Loss (pre-tax) Research and Development Sales and Marketing General and Administrative Total (in thousands) Total expense from foreign currency hedging $ 189 $ 39 $ 13 $ 241 $ 314 Effects of foreign currency cashflow hedging: Loss reclassified from condensed consolidated statement of comprehensive loss $ (189 ) (39 ) (13 ) (241 ) $ 241 Loss recognized in condensed consolidated statement of comprehensive loss $ — $ — $ — $ — $ 555

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Rental Payments for Operating Leases	The following is a schedule of future minimum lease payments under operating leases as of September 30, 2018 (in thousands): 2018 (remaining three months) $ 747 2019 2,819 2020 2,344 2021 1,900 2022 and beyond 4,055 Total minimum lease payments $ 11,865

Stockholders_ Equity (Tables)

Stockholders’ Equity (Tables)	9 Months Ended
	Sep. 30, 2018
Equity [Abstract]
Schedule of Stock by Class	The Company had reserved shares of common stock for issuance, on an as-converted basis, as follows: September 30, 2018 Options issued and outstanding 4,562,312 RSUs issued and outstanding 1,861,257 Shares available for ESPP 1,418,697 Shares available for future stock awards 2,580,091 10,422,357

Stock-based Compensation (Table

Stock-based Compensation (Tables)	9 Months Ended
	Sep. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs	Total stock-based compensation expense for employees and non-employees recognized in the condensed consolidated statements of operations was as follows: Three Months Ended Nine Months Ended September 30, October 1, September 30, October 1, (in thousands) Cost of revenue $ 50 $ 38 $ 146 $ 123 Research and development 2,248 1,367 7,170 3,986 Sales and marketing 541 416 2,118 1,179 General and administrative 1,163 948 3,489 2,159 Total stock-based compensation expense $ 4,002 $ 2,769 $ 12,923 $ 7,447 The above stock-based compensation expense related to the following equity-based awards: Three Months Ended Nine Months Ended September 30, October 1, September 30, October 1, (in thousands) Stock options $ 1,010 $ 858 $ 3,186 $ 2,539 RSU awards 2,753 1,603 8,269 3,553 ESPP shares 239 308 1,468 1,355 Total stock-based compensation expense $ 4,002 $ 2,769 $ 12,923 $ 7,447

The Company and Summary of Si_4

The Company and Summary of Significant Accounting Policies (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Estimate of breakage	$ 0.2	$ 0.6

The Company and Summary of Si_5

The Company and Summary of Significant Accounting Policies (Revenue, Geographical) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Oct. 01, 2017	Sep. 30, 2018	Oct. 01, 2017
Disaggregation of Revenue [Line Items]
Revenue	$ 59,349	$ 50,108	$ 157,893	$ 135,084
Percentage of revenue	100.00%	100.00%	100.00%	100.00%
Asia-Pacific
Disaggregation of Revenue [Line Items]
Revenue	$ 54,832	$ 46,864	$ 144,528	$ 125,040
Percentage of revenue	92.00%	94.00%	92.00%	93.00%
Europe, Middle East and Africa
Disaggregation of Revenue [Line Items]
Revenue	$ 4,409	$ 3,051	$ 13,221	$ 9,789
Percentage of revenue	8.00%	6.00%	8.00%	7.00%
Americas
Disaggregation of Revenue [Line Items]
Revenue	$ 108	$ 193	$ 144	$ 255
Percentage of revenue	0.00%	0.00%	0.00%	0.00%

Earnings Per Share (Schedule of

Earnings Per Share (Schedule of Eanings Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Oct. 01, 2017	Sep. 30, 2018	Oct. 01, 2017
Earnings Per Share [Abstract]
Net income	$ 3,879	$ 2,802	$ 1,664	$ 2,087
Weighted average shares used to compute basic and diluted net income per share:
Weighted-average shares outstanding (in shares)	37,070	34,734	36,476	33,907
Dilutive effect of stock options, ESPP and RSUs (in shares)	2,956	3,791	2,949	4,512
Weighted average shares outstanding - diluted (in shares)	40,026	38,525	39,425	38,419
Net income per share:
Basic (usd per share)	$ 0.10	$ 0.08	$ 0.05	$ 0.06
Diluted (usd per share)	$ 0.10	$ 0.07	$ 0.04	$ 0.05

Earnings Per Share (Schedule _2

Earnings Per Share (Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share) (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Oct. 01, 2017	Sep. 30, 2018	Oct. 01, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation (in shares)	1,352	776	1,616	1,553
Shares available for Employee Stock Purchase Plan (ESPP)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation (in shares)	16	0	8	0
Restricted Stock Units (RSUs)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation (in shares)	47	104	172	881
Options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation (in shares)	1,289	672	1,436	672

Balance Sheets Components (Mark

Balance Sheets Components (Marketable Securities) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Schedule of Investments [Line Items]
Amortized Cost	$ 97,777	$ 94,459
Gross Unrealized Gains	6	7
Gross Unrealized Losses	(312)	(271)
Fair Value	97,471	94,195
Commercial paper
Schedule of Investments [Line Items]
Amortized Cost	91,438	83,570
Gross Unrealized Gains	6	7
Gross Unrealized Losses	(291)	(250)
Fair Value	91,153	83,327
Government debt securities
Schedule of Investments [Line Items]
Amortized Cost	6,339	10,889
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(21)	(21)
Fair Value	$ 6,318	$ 10,868

Balance Sheets Components (Amor

Balance Sheets Components (Amortized Cost and Fair Value) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Amortized Cost
Due in one year or less	$ 79,848	$ 49,201
Due after one year to five years	17,929	45,258
Amortized Cost	97,777	94,459
Fair Value
Due in one year or less	79,668	49,144
Due after one year to five years	17,803	45,051
Total, fair value	$ 97,471	$ 94,195

Balance Sheets Components (Sche

Balance Sheets Components (Schedule of Property and Equipment) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Oct. 01, 2017	Sep. 30, 2018	Oct. 01, 2017	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 24,020		$ 24,020		$ 20,656
Accumulated depreciation and amortization	(10,602)		(10,602)		(8,145)
Property and equipment, net	13,418		13,418		12,511
Depreciation and amortization			3,467	$ 1,566
Computer and lab equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	16,950		16,950		14,295
Computer software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	968		968		795
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,739		1,739		1,589
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	4,363		4,363		$ 3,977
Tangible Assets
Property, Plant and Equipment [Line Items]
Depreciation and amortization	$ 900	$ 500	$ 2,700	$ 1,600

Balance Sheets Components (Sc_2

Balance Sheets Components (Schedule of Inventory) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Balance Sheets Components [Abstract]
Raw materials	$ 7,481	$ 5,812
Work in progress	2,121	1,069
Finished goods	11,976	5,781
Inventory, gross	$ 21,578	$ 12,662

Balance Sheets Components (Accr

Balance Sheets Components (Accrued Liabilities and Other Current Liabilities) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Balance Sheets Components [Abstract]
Accrued customer rebates	$ 9,044	$ 8,710
Accrued payroll and related benefits	5,683	3,411
Accrued expenses	2,688	4,507
Accrual for inventory purchases	980	2,124
ESPP employee contributions	2,261	706
Other	2,564	1,607
Accrued liabilities and other current liabilities	$ 23,220	$ 21,065

Fair Value Measurements (Assets

Fair Value Measurements (Assets, Recurring Basis) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 4,401	$ 6,398
Marketable securities	97,471	94,195
Total cash equivalents and marketable securities	101,872	100,593
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	1,254	4,398
Marketable securities	0	0
Total cash equivalents and marketable securities	1,254	4,398
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	3,147	2,000
Marketable securities	97,471	94,195
Total cash equivalents and marketable securities	100,618	96,195
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Marketable securities	0	0
Total cash equivalents and marketable securities	0	0
Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	1,254	4,398
Money market funds | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	1,254	4,398
Money market funds | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Money market funds | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	2,499	2,000
Marketable securities	91,153	83,329
Commercial paper | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Marketable securities	0	0
Commercial paper | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	2,499	2,000
Marketable securities	91,153	83,329
Commercial paper | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Marketable securities	0	0
Government debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	648
Marketable securities	6,318	10,866
Government debt securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0
Marketable securities	0	0
Government debt securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	648
Marketable securities	6,318	10,866
Government debt securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0
Marketable securities	$ 0	$ 0

Fair Value Measurements (Fair V

Fair Value Measurements (Fair Value of Derivatives) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability	$ 800	$ 0
Designated as Hedging Instrument | Foreign Exchange Forward
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset, notional amount	2,276
Derivative asset, fair value	17
Derivative liability, notional amount	21,946
Derivative liability, fair value	861
Current assets | Designated as Hedging Instrument | Foreign Exchange Forward
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset, notional amount	309
Derivative asset, fair value	3
Non-current assets | Designated as Hedging Instrument | Foreign Exchange Forward
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset, notional amount	1,967
Derivative asset, fair value	14
Current liabilities | Designated as Hedging Instrument | Foreign Exchange Forward
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, notional amount	18,021
Derivative liability, fair value	768
Non-current liabilities | Designated as Hedging Instrument | Foreign Exchange Forward
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liability, notional amount	3,925
Derivative liability, fair value	$ 93

Fair Value Measurements (Schedu

Fair Value Measurements (Schedule of Warrants) (Details) - Common Stock Warrants - Issued September 2015 - $ / shares	Sep. 30, 2018	Dec. 31, 2017
Class of Warrant or Right [Line Items]
Warrants exercised (in shares)	58,006	83,006
Exercise price (USD per share)	$ 2.50	$ 2.5
Number of warrants outstanding (in shares)	0	83,006

Derivative Financial Instrume_3

Derivative Financial Instruments (Location and Amount of Gain or (Loss) Recognized in Income on Fair Value and Cash Flow Hedging Relationships) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Oct. 01, 2017	Sep. 30, 2018	Oct. 01, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) reclassified from condensed consolidated statement of comprehensive loss	$ (247)	$ 0	$ (664)	$ 0
Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Loss recognized in condensed consolidated statement of comprehensive loss			0
Designated as Hedging Instrument | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) reclassified from condensed consolidated statement of comprehensive loss			(241)
Condensed Consolidated Statement of Comprehensive Loss (pre-tax) | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Loss recognized in condensed consolidated statement of comprehensive loss			555
Condensed Consolidated Statement of Comprehensive Loss (pre-tax) | Designated as Hedging Instrument | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) reclassified from condensed consolidated statement of comprehensive loss			241
Research and development | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Loss recognized in condensed consolidated statement of comprehensive loss			0
Research and development | Designated as Hedging Instrument | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) reclassified from condensed consolidated statement of comprehensive loss			(189)
Sales and marketing | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Loss recognized in condensed consolidated statement of comprehensive loss			0
Sales and marketing | Designated as Hedging Instrument | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) reclassified from condensed consolidated statement of comprehensive loss			(39)
General and administrative | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Loss recognized in condensed consolidated statement of comprehensive loss			0
General and administrative | Designated as Hedging Instrument | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) reclassified from condensed consolidated statement of comprehensive loss			(13)
Foreign Exchange Forward | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Total expense from foreign currency hedging			241
Foreign Exchange Forward | Condensed Consolidated Statement of Comprehensive Loss (pre-tax) | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Total expense from foreign currency hedging			314
Foreign Exchange Forward | Research and development | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Total expense from foreign currency hedging			189
Foreign Exchange Forward | Sales and marketing | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Total expense from foreign currency hedging			39
Foreign Exchange Forward | General and administrative | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Total expense from foreign currency hedging			$ 13

Commitments and Contingencies_2

Commitments and Contingencies (Details) $ in Thousands	Sep. 30, 2018USD ($)
Commitments and Contingencies Disclosure [Abstract]
2018 (remaining three months)	$ 747
2,019	2,819
2,020	2,344
2,021	1,900
2022 and beyond	4,055
Total minimum lease payments	$ 11,865

Commitments and Contingencies_3

Commitments and Contingencies (Narrative) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Oct. 01, 2017	Sep. 30, 2018	Oct. 01, 2017
Other Commitments [Line Items]
Rent expense	$ 700,000	$ 400,000	$ 2,200,000	$ 1,200,000
Purchase obligation	16,900,000		16,900,000
Indemnification Agreement
Other Commitments [Line Items]
Guarantor obligations	$ 0		$ 0

Commitments and Contingencies_4

Commitments and Contingencies (RUSNANO) (Details) - Investor - Agreement with RUSNANO	Sep. 30, 2018USD ($)	Jul. 31, 2014USD ($)period
Related Party Transaction [Line Items]
Contractual obligation		$ 13,000,000
Annual periods | period		6
Contractual obligation, year 1		$ 2,200,000
Contractual obligation, year 2		1,700,000
Contractual obligation, year 3		2,000,000
Contractual obligation, year 4		2,200,000
Contractual obligation, year 5		2,400,000
Contractual obligation, year 6		$ 2,500,000
Funding obligation penalty		10.00%
Difference between the funding obligation and the actual funding		80.00%
Funding obligation incurred	$ 0

Commitments and Contingencies_5

Commitments and Contingencies (Obligations) (Details) - Licensing Agreements [Member] - Noncancellable Obligations $ in Millions	Sep. 30, 2018USD ($)
Other Commitments [Line Items]
Contractual obligation	$ 3
Payable in fiscal 2018	0.3
Contractual obligation, year 2	$ 2.7

Long-term Debt (Details)

Long-term Debt (Details) $ in Millions	Jan. 02, 2018USD ($)
SVB Loan And Security Agreement
Debt Instrument [Line Items]
Repayments of debt	$ 3.9

Stockholders_ Equity (Details)

Stockholders’ Equity (Details)	Sep. 30, 2018vote$ / sharesshares	Dec. 31, 2017$ / sharesshares
Equity [Abstract]
Common stock, shares authorized (in shares)	1,000,000,000	1,000,000,000
Common stock, par value (usd per share) | $ / shares	$ 0.0001	$ 0.0001
Votes per share | vote	1
Options issued and outstanding (in shares)	4,562,312
RSUs issued and outstanding (in shares)	1,861,257
Shares available for ESPP (in shares)	1,418,697
Shares available for future stock awards (in shares)	2,580,091
Shares reserved for future issuance (in shares)	10,422,357

Stockholders_ Equity (Narrative

Stockholders’ Equity (Narrative 1) (Details) - shares	9 Months Ended
	Sep. 30, 2018	Oct. 01, 2017
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period (in shares)	1,489,046	1,041,629
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period (in shares)	666,250	516,750

Stockholders_ Equity (Narrati_2

Stockholders’ Equity (Narrative 2) (Details)	3 Months Ended	9 Months Ended
	Sep. 30, 2018shares	Sep. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Repurchase rights expiration per month of shares	0.0278	0.0278
Expiration period of repurchase program		36 months
Shares repurchased (in shares)	22,000

Stock-based Compensation (Detai

Stock-based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Oct. 01, 2017	Sep. 30, 2018	Oct. 01, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 4,002	$ 2,769	$ 12,923	$ 7,447
Cost of revenue
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	50	38	146	123
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	2,248	1,367	7,170	3,986
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	541	416	2,118	1,179
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 1,163	$ 948	$ 3,489	$ 2,159

Stock-based Compensation (Equit

Stock-based Compensation (Equity Based Awards Compensation Costs) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Oct. 01, 2017	Sep. 30, 2018	Oct. 01, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 4,002	$ 2,769	$ 12,923	$ 7,447
Stock options
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	1,010	858	3,186	2,539
RSU awards
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	2,753	1,603	8,269	3,553
ESPP shares
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 239	$ 308	$ 1,468	$ 1,355

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Oct. 01, 2017	Sep. 30, 2018	Oct. 01, 2017
Income Tax Disclosure [Abstract]
Provision for income taxes	$ (648)	$ (274)	$ (1,115)	$ 470

Employee Benefit Plans (Details

Employee Benefit Plans (Details) $ in Millions	9 Months Ended
	Sep. 30, 2018USD ($)
Retirement Benefits [Abstract]
Contribution amount by Company	$ 0.4

Related Party transactions (Nar

Related Party transactions (Narrative) (Details) - Lip-Bu Tan - USD ($) $ in Millions	3 Months Ended			6 Months Ended	9 Months Ended
	Sep. 30, 2018	Jul. 01, 2018	Oct. 01, 2017	Jul. 01, 2018	Oct. 01, 2017
Software License Arrangement
Related Party Transaction [Line Items]
Intangible assets	$ 2.4
Amortization of intangible assets		$ 0.8	$ 2	$ 0.5	$ 3.7
Integrated Circuits
Related Party Transaction [Line Items]
Purchases from related party	$ 1.8