Quantenna Communications (QTNA) 10-K 28 Feb 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2017	Feb. 27, 2018	Jun. 30, 2017
Document and Entity Information [Abstract]
Entity Registrant Name	QUANTENNA COMMUNICATIONS INC
Entity Central Index Key	1,370,702
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Entity Public Float			$ 415,925,257
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Amendment Flag	false
Entity common stock, shares outstanding		36,008,844

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Jan. 01, 2017
Current assets
Cash and cash equivalents	$ 24,432	$ 117,045
Marketable securities	94,195	0
Accounts receivable	26,786	14,480
Inventory	12,662	15,820
Prepaid expenses and other current assets	2,744	2,470
Total current assets	160,819	149,815
Deferred tax assets, net	35,422	0
Property and equipment, net	12,511	4,742
Intangible assets, net	2,987	0
Other long-term assets	965	232
Total assets	212,704	154,789
Current liabilities
Accounts payable	2,077	7,776
Accrued liabilities and other current liabilities	22,742	11,801
Long-term debt, current portion	3,943	2,257
Total current liabilities	28,762	21,834
Long-term debt	0	3,680
Other long-term liabilities	3,339	527
Total liabilities	32,101	26,041
Commitments and contingencies (see Note 6)
Stockholders’ equity
Common stock: $0.0001 par value, 1,000,000,000 shares authorized at December 31, 2017 and January 1, 2017, 35,528,880 and 33,076,150 shares issued and outstanding at December 31, 2017 and January 1, 2017, respectively	3	3
Additional paid-in capital	308,023	290,319
Accumulated other comprehensive loss	(207)	0
Accumulated deficit	(127,216)	(161,574)
Total stockholders’ equity	180,603	128,748
Total liabilities and stockholders’ equity	$ 212,704	$ 154,789

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2017	Jan. 01, 2017
Statement of Financial Position [Abstract]
Common stock, par value (in 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)	35,528,880	33,076,150
Common stock, shares outstanding (in shares)	35,528,880	33,076,150

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Jan. 01, 2017	Dec. 27, 2015
Income Statement [Abstract]
Revenue	$ 176,359	$ 129,069	$ 83,773
Cost of revenue	88,208	64,640	42,554
Gross profit	88,151	64,429	41,219
Operating expenses:
Research and development	59,747	46,604	35,575
Sales and marketing	14,040	8,091	6,644
General and administrative	15,299	10,559	5,212
Total operating expenses	89,086	65,254	47,431
Loss from operations	(935)	(825)	(6,212)
Interest expense	(713)	(665)	(697)
Other income (expense), net	1,118	(38)	(21)
Loss before income taxes	(530)	(1,528)	(6,930)
Benefit (provision) for income taxes	34,942	(367)	(115)
Net income (loss)	$ 34,412	$ (1,895)	$ (7,045)
Net income (loss) per share:
Basic (dollars per share)	$ 1	$ (0.30)	$ (9.16)
Diluted (dollars per share)	$ 0.89	$ (0.30)	$ (9.16)
Weighted-average number of shares used in per share calculations:
Basic (shares)	34,259	6,385	769
Diluted (shares)	38,484	6,385	769

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Jan. 01, 2017	Dec. 27, 2015
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 34,412	$ (1,895)	$ (7,045)
Other comprehensive loss, net of tax:
Unrealized losses on available-for-sale marketable securities	(264)	0	0
Tax benefit from unrealized losses on available-for-sale marketable securities	57	0	0
Other comprehensive loss, net of tax	(207)	0	0
Comprehensive income (loss)	$ 34,205	$ (1,895)	$ (7,045)

Consolidated Statements of Conv

Consolidated Statements of Convertible Preferred Stock and Stockholders’ Equity (Deficit) - USD ($) $ in Thousands	Total	Additional Paid-In Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit	Convertible Preferred Stock	Common Stock	Series G Convertible Preferred Stock Convertible Preferred Stock
Beginning balance (in shares) at Dec. 28, 2014					21,420,957	695,660
Beginning, stockholders' equity at Dec. 28, 2014	$ (149,993)	$ 2,641	$ 0	$ (152,634)	$ 170,448	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock for exercise of options (in shares)						121,880
Issuance of common stock for exercise of options	150	150
Issuance of common stock for exercise of warrants (in shares)						288,700
Issuance of common stock for exercise of warrants	14	14
Issuance of Series G convertible preferred stock, net of issuance costs (in shares)							1,050,579.82
Issuance of Series G convertible preferred stock, net of issuance costs							$ 14,256
Stock-based compensation expense	1,202	1,202
Net income (loss)	(7,045)			(7,045)
Ending balance (in shares) at Dec. 27, 2015					22,471,537	1,106,240
Ending, stockholders' equity at Dec. 27, 2015	(155,672)	4,007	0	(159,679)	$ 184,704	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock for exercise of options (in shares)						329,017
Issuance of common stock for exercise of options	579	579
Issuance of common stock for exercise of warrants	96	96
Issuance of common stock for service provided (in shares)						2,777
Issuance of common stock for service provided	25	25
Issuance of Series G convertible preferred stock, net of issuance costs (in shares)						6,775,466
Issuance of Series G convertible preferred stock, net of issuance costs	97,419	97,418				$ 1
Conversion of preferred stock to common stock pursuant to IPO (in shares)					(22,471,537)	24,790,650
Conversion of preferred stock to common stock pursuant to IPO	184,704	184,702			$ (184,704)	$ 2
Conversion of preferred stock warrants to common stock warrants	342	342
Issuance of common stock upon exercise of options subject to repurchase (in shares)						72,000
Vesting of options subject to repurchase	85	85
Stock-based compensation expense	3,065	3,065
Net income (loss)	(1,895)			(1,895)
Ending balance (in shares) at Jan. 01, 2017					0	33,076,150
Ending, stockholders' equity at Jan. 01, 2017	128,748	290,319	0	(161,574)	$ 0	$ 3
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect adjustment of ASU 2016-09 (Note 1)		54		(54)
Issuance of common stock for exercise of options (in shares)						2,452,730
Issuance of common stock for exercise of options	7,253	7,253
Issuance costs related to initial public offering	(286)	(286)
Stock-based compensation expense	10,683	10,683
Change in unrealized loss on marketable securities, net of tax	(207)		(207)
Net income (loss)	34,412			34,412
Ending balance (in shares) at Dec. 31, 2017					0	35,528,880
Ending, stockholders' equity at Dec. 31, 2017	$ 180,603	$ 308,023	$ (207)	$ (127,216)	$ 0	$ 3

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Jan. 01, 2017	Dec. 27, 2015
Cash flows from operating activities
Net income (loss)	$ 34,412	$ (1,895)	$ (7,045)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Release of deferred tax asset valuation allowances	(35,333)	0	0
Depreciation and amortization	2,669	1,278	987
Stock-based compensation expense	10,683	3,065	1,202
Accretion of discount on investments	207	0	0
Non-cash interest expense, net	474	347	271
Change in fair value of convertible preferred stock warrants liability	0	87	61
Non-cash foreign exchange gain	(46)	0	0
Changes in assets and liabilities:
Accounts receivable	(12,306)	1,237	(5,877)
Inventory	3,158	(8,413)	3,387
Prepaid expenses and other current assets	(335)	(901)	541
Deferred rent and other assets	(467)	(50)	60
Accounts payable	(5,752)	1,804	(4,401)
Accrued liabilities and other current liabilities	9,265	5,757	934
Deferred revenue	0	0	(2,197)
Net cash provided by (used) in operating activities	6,629	2,316	(12,077)
Cash flows from investing activities
Purchase of property and equipment	(8,970)	(2,724)	(1,761)
Purchase of marketable securities	(131,790)	0	0
Proceeds from sales of marketable securities	10,684	0	0
Maturities of marketable securities	26,440	0	0
Restricted cash	0	(59)	59
Net cash used in investing activities	(103,636)	(2,783)	(1,702)
Cash flows from financing activities
Proceeds from issuance of convertible preferred stock, net of issuance costs	0	0	14,256
Proceeds from issuance of common stock	7,675	1,191	164
Payment of taxes withheld for vested stock awards	(626)	0	0
Proceeds from initial public offering, net of issuance costs	(96)	97,483	0
Proceeds from revolving line of credit, net of fees paid	0	2,950	0
Repayment of revolving line of credit	0	(3,000)	0
Proceeds from issuance of long-term debt, net of fees paid	0	3,854	3,000
Payments related to intangible asset purchase	(266)	0	0
Repayments of long-term debt	(2,406)	(3,816)	(3,111)
Net cash provided by financing activities	4,281	98,662	14,309
Effect of Exchange Rate on Cash and Cash Equivalents	113	0	0
Net increase (decrease) in cash and cash equivalents	(92,613)	98,195	530
Beginning of year	117,045	18,850	18,320
End of year	24,432	117,045	18,850
Supplemental disclosure of cash flow information
Interest paid during the period	224	489	440
Income taxes paid during the period	278	106	135
Supplemental disclosure of non-cash investing and financing activities
Unpaid offering costs	254	64	0
Purchases of property and equipment included in accounts payable and accrued liabilities and other current liabilities	433	213	0
Intangible asset, capitalized	3,259	0	0
Issuance of warrants in conjunction with the execution of debt agreement	0	96	0
Conversion of convertible preferred stock warrants to common stock
Supplemental disclosure of non-cash investing and financing activities
Conversion of convertible preferred stock	0	342	0
Conversion of convertible preferred stock to common stock
Supplemental disclosure of non-cash investing and financing activities
Conversion of convertible preferred stock	$ 0	$ 184,704	$ 0

The Company and Summary of Sign

The Company and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
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. The fiscal years ended on December 31, 2017 , January 1, 2017 and December 27, 2015 consisted of 52 weeks, 53 weeks and 52 weeks, respectively. Initial Public Offering On October 27, 2016, the Company’s registration statement on Form S-1 relating to its initial public offering (“IPO”) of its common stock was declared effective by the Securities and Exchange Commission (“SEC”) and the shares of its common stock began trading on The NASDAQ Global Select Market on October 28, 2016. The public offering price of the shares sold in the IPO was $16.00 per share. The IPO closed on November 2, 2016 and a second closing occurred on November 25, 2016 , pursuant to which the Company sold a total of 6,775,466 shares of its common stock, including the sale of 75,466 shares of common stock to the underwriters upon their exercise of their option to purchase additional shares. The Company received net proceeds of approximately $97.4 million , after underwriting discounts, commissions and offering expenses. Immediately prior to the consummation of the IPO, all outstanding shares of convertible preferred stock and preferred stock warrants were converted into common stock and common stock warrants, respectively. Use of Estimates Preparation of financial statements in conformity with accounting principles generally accepted in the United States of America, or 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. Actual results could differ from those estimates. Principles of Consolidation The consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany transactions and balances have been eliminated in consolidation. Foreign Currency Remeasurement The Company and its subsidiaries use the U.S. dollar as the functional currency. Foreign currency assets and liabilities are remeasured into U.S. dollars at the end-of-period exchange rates except for non-monetary assets and liabilities, which are measured at historical exchange rates. Revenue and expenses are remeasured using an average exchange rate for the respective period, except for expenses related to non-monetary assets and liabilities, which are measured at historical exchange rates. Gains or losses from foreign currency remeasurement and transactions are included in “Other income (expense), net”. For the years ended December 31, 2017 , January 1, 2017 and December 27, 2015 , foreign currency remeasurement and transactions gains and losses were immaterial. Cash and Cash Equivalents Cash equivalents include liquid short-term investments with original or remaining maturities of three months or less at the date of purchase, readily convertible to known amounts of cash. Marketable Securities Marketable securities consist primarily of highly liquid investments with maturities of greater than 90 days when purchased. We generally classify our marketable securities at the date of acquisition as available-for-sale. These securities are reported at fair value with the related unrealized gains and losses included in " Accumulated other comprehensive loss ", a component of stockholders’ equity, net of tax. Any unrealized losses which are considered to be other-than-temporary impairments are recorded in " Other income (expense), net " in the Consolidated Statements of Operations. Realized gains (losses) on the sale of marketable securities are determined using the specific-identification method and recorded in " Other income (expense), net " in the Consolidated Statements of Operations. All of our available-for-sale investments are subject to a periodic impairment review. We record a charge to earnings when a decline in fair value is significantly below cost basis and judged to be other-than-temporary, or have other indicators of impairments. If the fair value of an available-for-sale investment is less than its amortized cost basis, an other-than-temporary impairment is triggered in circumstances where (1) we intend to sell the instrument, (2) it is more likely than not that we will be required to sell the instrument before recovery of its amortized cost basis or (3) a credit loss exists where we do not expect to recover the entire amortized cost basis of the instrument. If we intend to sell or it is more likely than not that we will be required to sell the available-for-sale investment before recovery of its amortized cost basis, we recognize an other-than temporary impairment charge equal to the entire difference between the investment's amortized cost basis and its fair value. Fair Value of Financial Instruments The carrying amounts of the Company’s financial instruments, which include cash equivalents, accounts receivable, accounts payable and accrued liabilities and other current liabilities, approximate their fair values due to their short maturities. Estimates of fair value of our marketable securities are based on quoted market prices from active markets or third party, market-based pricing sources which we believe to be reliable. The estimated fair value of the Company’s debt approximates the carrying value because the interest rate on the borrowings approximates market rates and was determined to be a Level 2 instrument. The Company also has issued certain convertible preferred stock warrants which are accounted for as liabilities at fair value. In November 2016, pursuant to the consummation of the IPO, all outstanding convertible preferred stock warrants were converted into common stock warrants and the warrant liability was reclassified to additional paid-in capital. See Note 5 , “Fair Value Measurements,” of the Notes to Consolidated Financial Statements included elsewhere in this Annual Report on Form 10-K for further details. Accounts Receivable and Allowances for Doubtful Accounts Accounts receivable are stated at invoice value less estimated allowances for returns and doubtful accounts. The Company continually monitors customer payments and maintains an allowance for estimated losses resulting from its customers’ inability to make required payments. The Company considers factors such as historical experience, credit quality, age of the accounts receivable balances, geographic related risks and economic conditions that may affect a customer’s ability to pay. In cases where there are circumstances that may impair a specific customer’s ability to meet its financial obligations, a specific allowance is recorded against amounts due, which reduces the net recognized receivable to the amount reasonably believed to be collectible. For all periods presented, the Company concluded that no allowance for doubtful accounts was necessary. Concentration of Credit Risk Financial instruments that potentially subject the Company to significant concentrations of credit risk consist principally of cash and cash equivalents, marketable securities and accounts receivable. We invest our excess cash primarily in banks, money market funds, government debt securities and corporate debt securities. We have established guidelines relative to credit ratings, diversification and maturities that seek to maintain safety and liquidity. The Company generally requires no collateral from its customers. For the years ended December 31, 2017 , January 1, 2017 and December 27, 2015 , one , three and four customers accounted for 10% or more of revenue, respectively. The following table discloses these customers’ percentage of revenue for the respective periods: Years Ended December 31, January 1, December 27, Customer A * 19% 14% B 16% 11% 15% C * 11% * D * * 11% E * * 10% ________________________ * Total customer percentage of revenue was less than 10% . At December 31, 2017 and January 1, 2017 , three and three customers accounted for 10% or more of accounts receivable, respectively as stated below: December 31, January 1, Customer A 12% 30% B 31% 12% C 14% 12% ________________________ Restricted Cash The Company maintained $59 thousand of restricted cash in certificate of deposit accounts at December 31, 2017 and January 1, 2017 , supporting letters of credit required for the Company’s operating lease facility and deposits required by the Company’s foundry partner in connection with its purchase of silicon wafers. Restricted cash is included in Prepaid expenses and other current assets on the consolidated balance sheets. Inventory Inventory is stated at the lower of cost to purchase or manufacture the inventory or the market value of such inventory. Cost is determined using the standard cost method which approximates the first-in first-out basis. Market value is determined as the lower of replacement cost or net realizable value. The Company, at least quarterly, assesses the recoverability of all inventories to determine whether adjustments are required to record inventory at the lower of cost or market. Potentially excess and obsolete inventory is written off based on management’s analysis of inventory levels and estimates of future 12-month demand and market conditions. The Company is also entitled to receive rebates from its foundry partner on the purchase of silicon wafers upon achieving certain volume targets. Rebates from the Company’s foundry partner are recorded as a reduction of inventory cost when it is probable and reasonably estimable, and are recognized in cost of revenue as the chipsets made from such silicon wafers are sold to customers. Prepaid Expenses and Other Current Assets The Company purchases rights to software and intellectual property used in the development of its Wi-Fi solutions. Certain of the arrangements require payment over the life of the right to use the related software and intellectual property. The Company records the up-front fees and periodic payments in prepaid expenses and other current assets and amortizes the amount over the life of the arrangement using the straight-line method. Debt Issuance Costs and Debt Discounts Costs incurred in connection with the issuance of new debt are capitalized and amounts paid in connection with the modification of existing debt are expensed as incurred. Capitalizable debt issuance costs paid to third parties and debt discounts paid to creditors, net of amortization, are recorded as a reduction to the long-term debt balance on the consolidated balance sheets. Amortization expense on capitalized debt issuance costs and debt discounts related to loans with fixed payment terms is calculated using the effective interest method over the term of the associated loans. Amortization expense on capitalized debt issuance costs and debt discounts related to revolving loans are calculated using the straight-line method over the term of the revolving loan commitment, and is recorded as Interest expense in the consolidated statements of operations. When debt is extinguished prior to the maturity date, any remaining associated debt issuance costs or debt discounts are expensed to Interest expense in the consolidated statements of operations. Property and Equipment Property and equipment are stated at cost and depreciated using the straight‑line method over the estimated useful lives of the assets as follows: Computer and lab equipment 3 to 5 years Computer software 3 years Furniture and fixtures 3 to 7 years Leasehold improvements Shorter of remaining lease term or estimated useful lives of the assets Costs of maintenance and repairs that do not improve or extend the lives of the respective assets are expensed as incurred. Upon retirement or sale, the cost and related accumulated depreciation are removed from the consolidated balance sheets and the resulting gain or loss is reflected in operating expenses. Intangible Assets Definite long-lived intangible assets consist of software licenses which are recorded based on the total contractual price. Such assets are amortized over its contractual lives and are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. If it is determined that such assets are not recoverable, an impairment charge is recognized for the amount by which the carrying amount of such assets exceeds their fair values. There was no impairment of definite long-lived intangible assets for the periods presented. As of December 31, 2017 , the Company’s definite long-lived intangible assets amounted to approximately $3.0 million , net of accumulated amortization of $0.3 million . Impairment of Long-Lived Assets The Company evaluates its long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. When the sum of the undiscounted future net cash flows expected to result from the use of the asset or asset group and its eventual disposition is less than its carrying amount, an impairment loss would be measured based on the discounted cash flows compared to the carrying amount attributable to the asset group. No impairment loss has been recognized for the periods presented. Warranty The Company provides 12 -month warranty coverage on all of its Wi-Fi solutions. The warranty provides for replacement of the associated Wi-Fi solutions during the warranty period. The Company establishes a liability for estimated warranty costs at the time revenue is recognized. The warranty obligation is affected by historical failure rates and associated replacement costs. The warranty liability is included in accrued liabilities and other current liabilities on the consolidated balance sheets. The warranty liability and activity for the periods presented were immaterial. Income Taxes The Company recognizes deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements or tax returns. The Company recognizes future tax benefits, measured by enacted tax rates attributable to deductible temporary differences between financial statements and income tax bases of assets and liabilities, and net operating loss carry-forwards to the extent that realization of such benefits is more likely than not. The Company records a liability for the difference between the benefit recognized and measured pursuant to the accounting guidance on accounting for uncertain tax positions and the tax position taken or expected to be taken on the Company’s tax return. To the extent that the assessment of such tax positions changes, the change in estimate is recorded in the period in which the determination is made. The Company establishes these liabilities based on estimates of whether, and the extent to which, additional taxes will be due. These liabilities are established when the Company believes that certain positions might be challenged despite the Company’s belief that the tax return positions are fully supportable. The liabilities are adjusted in light of changing facts and circumstances, such as the outcome of tax audits. Revenue Recognition The Company derives a majority of its revenue from the sale of Wi-Fi solutions. Revenue is recognized net of accruals for sales returns and rebates. The Company account for rebates to end-user customers based on the maximum amount of rebate contractually due under the terms of the arrangement. Claims for customer rebates are charged to the customer rebate accrual when received and approved. Accrued customer rebates are released to revenue only at such time the rebate liability has been extinguished or is considered remote. During the fourth quarter of fiscal 2017, the Company undertook a process to confirm accrued customer rebate balances and obtain confirmation, where possible, from customers of amounts outstanding under customer rebate programs. This confirmation process provided new evidence that the probability of certain customer rebate liabilities being claimed was remote and accordingly the related accrual was reversed and recorded as revenue. The total amount of customer rebate accrual reversed and recorded in revenue during the fourth quarter of fiscal 2017 amounted to approximately $2.0 million . The Company recognizes revenue when persuasive evidence of an arrangement exists, delivery has occurred, the price is deemed fixed or determinable and collection is reasonably assured. These criteria are met upon shipment to customers. For sales made through distributors, revenue is recognized when title passes to the distributor upon shipment, and payment by the Company’s distributors is not contingent on resale of the Wi-Fi solutions. The Company’s sales arrangements with distributors do not allow for rights of return or price protection on unsold Wi-Fi solutions. The Company’s policy is to classify shipping and handling costs, net of costs charged to customers, as cost of revenue. The Company also derives revenues from contracts with multiple deliverables, including a mix of intellectual property licenses, research and development services, and other non-recurring arrangements. While licensing and non-recurring arrangements are not part of primary focus, we may enter into such arrangements on an opportunistic basis from time to time. Revenue recognition for contracts with multiple deliverables is based on the individual units of accounting determined to exist in the contract. A delivered item is considered a separate unit of accounting when (i) the delivered item has value to the customer on a stand-alone basis; and (ii) if a general right of return exists, the delivery or performance of an undelivered item is considered probable and under the Company’s control. Items are considered to have a stand-alone value when they are sold separately by any vendor or when the customer could resell the item on a stand-alone basis. In addition, intellectual property deliverables are considered to have value on a stand-alone basis if the customer could use them without the remaining elements of the arrangement. When a deliverable does not meet the criteria to be considered a separate unit of accounting, it is grouped together with other deliverables that, when combined, meet the criteria, and the appropriate allocation of arrangement consideration and revenue recognition is determined. In April 2013, the Company entered into an agreement consisting of intellectual property licenses and research and development services. The Company determined that the two deliverables in the agreement did not meet the criteria to be accounted as separate units of accounting because the intellectual property licenses did not have a value on a standalone basis from the research and development services. As a result, the intellectual property licenses and research and development services was considered one combined unit of accounting. The fees under this agreement totaled $16.5 million , of which $0.5 million and $5.7 million was recognized as revenue for the year ended January 1, 2017 and December 27, 2015 , respectively. The agreement was terminated in 2016. Deferred Revenue Deferred revenue is comprised of billings or payments received in advance of meeting revenue recognition criteria. Research and Development Expenses All costs related to the research and development of the Company’s Wi-Fi solutions are expensed as incurred. Research and development (“R&D”) expense consists primarily of personnel costs for the Company’s R&D activities. R&D expense also includes costs associated with the design and development of the Company’s Wi-Fi solutions, such as mask sets, prototype wafers, prototype engineering boards, software and computer-aided design software licenses, intellectual property licenses, reference design development, development testing and evaluation, depreciation and amortization expense, and allocated administrative costs. Operating Leases The Company recognizes rent expense on a straight-line basis over the non-cancellable term of the operating lease. The difference between rent expense and rent paid is recorded as deferred rent in accrued liabilities and other current liabilities on the consolidated balance sheets. Advertising and Promotion Costs Expenses related to advertising and promotion of products are charged to sales and marketing expense as incurred. The Company incurred immaterial advertising or promotion expenses in the years ended December 31, 2017 , January 1, 2017 and December 27, 2015 , respectively. Stock-Based Compensation The Company measures and recognizes compensation expense for all stock-based awards made to employees, directors and non-employees, based on estimated fair values recognized using the straight-line method over the requisite service period. On January 1, 2017, the Company adopted the Financial Accounting Standards Board (“FASB”) Accounting Standards Update (“ASU”) 2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting . Under this guidance, the Company elected the option to no longer apply a forfeiture rate to the stock-based compensation expense, but to record forfeitures when they occur, and, as a result, under the modified retrospective method of adoption the Company recorded an immaterial cumulative effect adjustment of $54,000 to the opening accumulated deficit on January 2, 2017. The fair value of options and warrants to purchase common stock granted to employees is estimated on the grant date using the Black-Scholes option valuation model. The calculation of stock-based compensation expense requires that the Company make assumptions and judgments about the variables used in the Black-Scholes model, including the expected term, expected volatility of the underlying common stock and risk-free interest rate. The fair value for restricted stock awards is measured based on the closing market price of our common stock on the date of grant. The Company accounts for common stock warrants and options issued to non-employees under Accounting Standards Codification (“ASC”) Topic No. 505-50 Equity-Equity based payments to Non-Employees , using the Black-Scholes option valuation model. The fair value of such non-employee awards is remeasured at each quarter-end over the vesting period. Common Stock Warrants The Company accounts for common stock warrants as equity in accordance with the accounting guidance for derivatives. The accounting guidance provides a scope exception from classifying and measuring as a financial liability a contract that would otherwise meet the definition of a derivative if the contract is both (i) indexed to the entity’s own stock and (ii) meets the requirement for classification in the stockholders’ equity (deficit) section of the balance sheet. The Company determined that the common stock warrants issued in connection with the debt arrangement are required to be classified in equity. Warrants classified as equity are recorded as additional paid in capital on the consolidated balance sheets in stockholders’ equity (deficit) and no further adjustments to their valuation are made. The Company accounts for common stock warrants issued to non-employees for services under ASC 505-50. The fair value of such non-employee warrants is remeasured at each quarter-end over the vesting period. The Company determines the fair value of the common stock warrants using the Black-Scholes option valuation model using the stock price and other measurement assumptions as of the earlier of the date at which either (1) a commitment for performance by the counterparty has been reached; or (2) the counterparty’s performance is complete. Convertible Preferred Stock The Company recorded the convertible preferred stock at fair value on the dates of issuance, net of issuance costs. The convertible preferred stock is recorded outside of “Stockholders’ equity (deficit)” because, in the event of certain deemed liquidation events considered not solely within the Company’s control, such as a merger, acquisition and sale of all or substantially all of the Company’s assets, the convertible preferred stock will become redeemable at the option of the holders. The Company has not adjusted the carrying values of the convertible preferred stock to the liquidation preferences of such shares because it is uncertain whether or when an event would occur that would obligate the Company to pay the liquidation preferences to holders of shares of convertible preferred stock. Subsequent adjustments to the carrying values to the liquidation preferences will be made only when it becomes probable that such a liquidation event will occur. In November 2016, pursuant to the consummation of the IPO, all outstanding shares of convertible preferred stocks were converted into common stock. Convertible Preferred Stock Warrants Liability Warrants to purchase shares of convertible preferred stock are classified as liabilities on the consolidated balance sheets at fair value upon issuance because the underlying shares of convertible preferred stock are redeemable at the option of the holders upon the occurrence of certain deemed liquidation events considered not solely within the Company’s control, which may therefore obligate the Company to transfer assets at some point in the future. The convertible preferred stock warrants are subject to remeasurement to fair value at each balance sheet date and any change in fair value is recognized as a component of “Other income (expense), net” in the consolidated statements of operations. In November 2016, pursuant to the consummation of the IPO, all outstanding convertible preferred stock warrants were converted into common stock warrants and the warrant liability was reclassified to additional paid-in capital. Net Income (Loss) per Share Basic net income (loss) per share is calculated by dividing the net income (loss) by the weighted-average number of shares of common stock outstanding during the period, without consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss by the weighted-average number of shares of common stock, without consideration for potentially dilutive securities as the inclusion of such securities would be anti-dilutive. For purposes of the diluted net loss per share calculation, unvested stock awards, warrants, convertible preferred stock and unvested employee stock purchase plan awards are considered to be potentially dilutive securities. Diluted net income per share is calculated by dividing the net income by the weighted-average number of shares of common stock and potentially dilutive securities outstanding for the period. Basic and diluted net loss per share is presented in conformity with the two-class method required for participating securities as the convertible preferred stock is considered a participating security. In addition, the Company considers shares issued upon the early exercise of non-vested warrants to purchase common stock to be participating securities, as the holders of these shares have a non-forfeitable right to dividends. 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 loss per share attributable to common stockholders. The Company’s participating securities do not have a contractual obligation to share in the Company’s losses. As such, the net loss was attributed entirely to common stockholders. Deferred Offering Costs Deferred offering costs, consisted of legal, accounting and other fees and costs related to the Company’s IPO were capitalized within “Other assets” on the consolidated balance sheets until the consummation of the IPO. These offering costs were reclassified to common stock upon the closing of the initial public offering in November 2016. There were no deferred offering costs capitalized as of December 31, 2017 and January 1, 2017 . Reverse Stock Split In September 2016 and October 2016, respectively, the Company’s board of directors and stockholders approved a one-for- 50 reverse split of the Company’s common stock and convertible preferred stock (the “Reverse Stock Split”), which was effected on October 13, 2016. The board of directors and stockholders also approved a proportionate adjustment in the authorized number of shares of common stock and each series of convertible preferred stock and proportionate adjustments to the conversion prices, dividend rates, original issue prices and liquidation preferences of each series of preferred stock. The number of options and warrants to purchase common stock and convertible preferred stock were also proportionately adjusted to reflect the Reverse Stock Split. The par value of the common and convertible preferred stock was not adjusted as a result of the Reverse Stock Split. All share and per share information included in the accompanying financial statements and notes thereto have been adjusted to reflect the Reverse Stock Split.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements In August 2017, the FASB issued ASU No. 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 currently does not have any hedging activities but may evaluate the effects of this standard on its consolidated financial statements in future reporting periods. In May 2017, the FASB issued ASU No. 2017-09, Compensation-Stock Compensation (Topic 718): Scope of Modification Accounting (“ASU No 2017-09”). The amendments in ASU No. 2017-09 provide guidance about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting in Topic 718. ASU No. 2017-09 is effective for the Company for annual and interim reporting periods beginning January 1, 2018. Early adoption of ASU No. 2017-09 is permitted, including adoption in any interim period, and the standard should be applied prospectively to an award modified on or after the adoption date. The adoption of this standard is not expected to have a material impact on the Company’s consolidated financial statements. In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows - Restricted Cash , which requires entities to show the changes in the total of cash, cash equivalents, restricted cash and restricted cash equivalents in the statement of cash flow. This standard is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Early adoption is permitted, including adoption in an interim period, but any adjustments must be reflected as of the beginning of the fiscal year that includes that interim period. The new standard must be adopted retrospectively. The adoption of this standard is not expected to have a material impact on the Company’s consolidated statements of cash flows. In October 2016, the FASB issued ASU No. 2016-17, Consolidation - Interests Held through Related Parties That Are under Common Control , to amend the consolidation guidance on how a reporting entity that is the single decision maker of a variable interest entity should treat indirect interests in the entity held through related parties that are under common control within the reporting entity when determining whether it is the primary beneficiary of that variable interest entity. The standard is effective for fiscal years beginning after December 15, 2016, including interim periods within those fiscal years. Early adoption is permitted. The adoption of this standard did not have a material impact on the Company’s consolidated financial position and results of operations. In October 2016, the FASB issued ASU No. 2016-16, Income Taxes - Intra-Entity Transfers of Assets Other Than Inventory , which requires entities to recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. The standard is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Early adoption is permitted as of the beginning of a fiscal year. The new standard must be adopted using a modified retrospective transition method which is a cumulative-effective adjustment to retained earnings as of the beginning of the first effective reporting period. The Company is currently evaluating the effects, if any, that the adoption of this guidance will have on its consolidated financial statements. In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows - Classification of Certain Cash Receipts and Cash Payments , ASU No. 2016-15 addresses eight specific cash flow issues with the objective of reducing the existing diversity in practice in how certain cash receipts and cash payments are presented and classified in the statement of cash flows. The standard is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Early adoption is permitted, including adoption in an interim period. The adoption of this standard is not expected to have a material impact on the Company’s consolidated statements of cash flows. In February 2016, the FASB issued ASU No. 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 currently evaluating the effects, if any, that the adoption of this guidance will have on its consolidated financial statements. In January 2016, the FASB issued ASU No. 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities , which addresses certain aspects of recognition, measurement, presentation and disclosure of financial instruments. ASU No. 2016-01 is effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2017. The adoption of this standard is not expected to have a material impact on the Company’s consolidated financial statements. In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) , which supersedes the revenue recognition requirements in ASC 605, Revenue Recognition . This ASU No. 2014-09 is based on the principle that revenue is recognized to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The ASU No. 2014-09 also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments and assets recognized from costs incurred to obtain or fulfill a contract. In August 2015, FASB issued ASU No. 2015-14, Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date , which effectively delayed the adoption date by one year, to an effective date for public entities for annual and interim periods beginning after December 15, 2017. In March, April, May and December 2016, the FASB issued additional updates to the new revenue standard relating to reporting revenue on a gross versus net basis, identifying performance obligations and licensing arrangements, and narrow-scope improvements and practical expedients, respectively. The effective date of this additional update is the same as that of ASU No. 2014-09. The guidance permits the use of either a retrospective or cumulative effect transition method. The Company has determined it will implement Topic 606 using the modified retrospective transition method. The adoption of the provisions of the new standard is not expected to have a material impact on its consolidated financial position or results of operations. Based on the evaluation of its current contracts and revenue streams, under the new standard the Company has 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 will use historical data to determine an estimate of breakage which can be applied to the amount of customer rebate that is due under its contractual arrangements. The FASB has issued, and may issue in the future, interpretive guidance which may cause the Company’s evaluation to change. The Company believes it is following an appropriate timeline to allow for proper recognition, presentation and disclosure upon adoption effective the beginning of fiscal year 2018.

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2017
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: Years Ended December 31, January 1, December 27, (in thousands, except per share data) Net income (loss) $ 34,412 $ (1,895 ) $ (7,045 ) Weighted-average shares outstanding 34,309 6,454 775 Less: weighted average shares subject to repurchase due to early exercise (50 ) (69 ) (6 ) Weighted average shares used to compute basic net income (loss) per share 34,259 6,385 769 Dilutive effect of convertible preferred stock, warrants to purchase preferred stock, stock options, common stock warrants, ESPP and RSUs 4,225 — — Weighted average shares used to compute diluted net (income) loss per share 38,484 6,385 769 Net income (loss) per share: Basic $ 1.00 $ (0.30 ) $ (9.16 ) Diluted $ 0.89 $ (0.30 ) $ (9.16 ) 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: Years Ended December 31, 2017 January 1, 2017 December 27, 2015 (in thousands) Convertible preferred stock (as-converted) — — 24,791 Warrants to purchase convertible preferred stock — — 271 Warrants to purchase common stock — 477 283 Shares available for ESPP — 224 — Restricted Stock Units (RSUs) 1,095 7 — Options to purchase common stock 857 6,474 5,062 Total 1,952 7,182 30,407

Balance Sheets Components

Balance Sheets Components	12 Months Ended
	Dec. 31, 2017
Balance Sheets Components [Abstract]
Balance Sheets Components	Balance Sheets Components Marketable Securities Marketable securities at 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 There were no marketable securities as of January 1, 2017 . Property and equipment, net consisted of the following: December 31, January 1, (in thousands) Computer and lab equipment $ 14,295 $ 9,748 Computer software 795 625 Furniture and fixtures 1,589 136 Leasehold improvements 3,977 218 Sub-total 20,656 10,727 Accumulated depreciation and amortization (8,145 ) (5,985 ) Property and equipment, net $ 12,511 $ 4,742 Depreciation and amortization expense related to property and equipment was 2.4 million , $1.3 million and $1.0 million , for the years ended December 31, 2017 , January 1, 2017 and December 27, 2015 , respectively. Inventory Inventory consisted of the following: December 31, January 1, (in thousands) Raw materials $ 5,812 $ 9,067 Work in progress 1,069 1,128 Finished goods 5,781 5,625 $ 12,662 $ 15,820 Accrued Liabilities and Other Current Liabilities Accrued liabilities and other current liabilities consisted of the following: December 31, January 1, (in thousands) Accrued customer rebates $ 8,710 $ 3,026 Accrued expenses 6,184 2,952 Accrued payroll and related benefits 3,411 2,842 Accrual for inventory purchases 2,124 1,353 ESPP employee contributions 706 665 Other 1,607 963 $ 22,742 $ 11,801

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2017
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 its 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 its 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 Measured at Fair Value on a Recurring Basis The Company measures and reports certain assets at fair value on a recurring basis at December 31, 2017 and January 1, 2017 as follows: 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 Fair Value as of January 1, 2017 Level 1 Level 2 Level 3 Total Assets: Cash equivalents $ 100,876 $ — $ — $ 100,876 Common Stock 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 As of January 1, 2017 , warrants issued and outstanding were as follows: Date of Issuance Number of Warrants Exercise Price Expiration Date Common stock warrants October 2013 38,748 7.74 October 2023 Common stock warrants September 2015 283,005 2.50 February 2019 Common stock warrants February 2016 20,251 4.00 February 2019 Common stock warrants February 2016 9,000 0.05 January 2018 Common stock warrants May 2016 126,400 4.00 May 2026 During the year ended December 31, 2017 , common stock warrants issued in a) October 2013 to a lender of the Company at $7.74 per share was exercised, b) September 2015 to an investor of the Company was partially exercised at $2.50 per share, c) February 2016 at $4.00 per share was exercised, d) February 2016 to a service provider of the Company were exercised at $0.05 per share, and e) May 2016 to a lender of the Company at $4.00 per share were partially exercised and the remainder were canceled.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2017
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 December 31, 2017 (in thousands): 2018 $ 1,989 2019 2,269 2020 2,042 2021 1,629 2022 and beyond 3,732 Total minimum lease payments $ 11,661 The Company leases office space under arrangements expiring through 2026. Rent expense for the years ended December 31, 2017 , January 1, 2017 and December 27, 2015 was $1.9 million , $1.2 million and $1.2 million , respectively. In February 2017, the Company entered into a new lease agreement for its corporate headquarters located in San Jose, California consisting of approximately 84,000 square feet. The lease term is 76 months commencing on October 16, 2017 and expiring in 2024. Purchase Commitments The Company has purchase obligations of $37.2 million that are based on outstanding purchase orders as of December 31, 2017 , related to the fabrication of certain wafers for which production has started. These purchase orders are cancellable at any time, provided that the Company is required to pay 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 December 31, 2017 . 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 December 31, 2017 . Commitments In April 2012, an agreement was entered into with Joint Stock Company “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 December 31, 2017 , the Company had met the minimum funding requirements and no penalty had been incurred. As of December 31, 2017 , the Company’s non-cancellable obligations for its definite long-lived intangible assets which are comprised of software licenses were approximately $4.1 million , of which $1.5 million is due payable in fiscal 2018 and $2.6 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. In October 2016, Innovatio IP Ventures, LLC filed suit in the United States District Court for the Northern District of Illinois alleging infringement by the Company of nine expired U.S. patents. The matter was settled favorably for the Company in December 2017 for an immaterial amount.

Long-term Debt

Long-term Debt	12 Months Ended
	Dec. 31, 2017
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) revolving line of credit, and (iii) Mezzanine Loan. The term loans have interest at a floating rate per annum equal to prime plus 0.75% . The revolving line of credit has interest ranging from 4.25% to 5.00% depending on the Company’s consolidated leverage ratio. The Mezzanine Loan remained unused by the Company and was canceled upon its expiration in May 2017. 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 payment for the extinguishment of the term loans was processed on January 2, 2018. The Company reclassified the final $3.9 million payment on December 31, 2017 to “Long-term debt, current portion” in its Consolidated Balance Sheet as of such date. The SVB Loan and Security Agreement was collateralized by certain of the Company’s assets, including pledges of certain of the Company’s equity interests in its subsidiaries, receivables and inventory, subject to customary exceptions and limits. It also contained customary events of default upon the occurrence of certain events, such as nonpayment of amounts due under the revolving line of credit or the term loans, violation of restrictive covenants, violation of other contractual provisions, or a material adverse change in the Company’s business. In addition, the credit facilities prohibited the payment of cash dividends on the Company’s capital stock and also place restrictions on mergers, sales of assets, investments, incurrence of liens, incurrence of indebtedness and transactions with affiliates. The SVB Loan and Security Agreement had certain prepayment premium upon repayment before the maturity date. As of December 31, 2017 , the Company has an undrawn balance on the revolving line of credit of $20.0 million which can be drawn subject to 80% of eligible accounts receivable. The agreement contains usual and customary events of default upon the occurrence of certain events, such as nonpayment of amounts due under the revolving line of credit or the term loans, violation of the restrictive covenants, violation of other contractual provisions, or a material adverse change in its business. The agreement includes customary administrative covenants, including a prohibition on declaring dividends, but does not include any financial maintenance or operating related covenants. As of December 31, 2017 , there were no future minimum payments for the long-term debt as a result of the extinguishment of the term loans as of this date apart from the final payment of $3.9 million received by SVB on January 2, 2018. As of January 1, 2017 , future minimum payments for the long-term debt were as follows (in thousands): Long-term debt 2017 $ 2,570 2018 2,383 2019 1,618 Total minimum payments 6,571 Less: Amount representing interest (357 ) Less: Amount representing closing and repayment fees (330 ) Present value of minimum payments 5,884 Less: Unamortized debt discounts (167 ) Plus: Accretion of closing and repayment fees 220 Long-term debt, net 5,937 Less: Long-term debt, current portion (2,257 ) Non-current portion of long-term debt $ 3,680

Convertible Preferred Stock

Convertible Preferred Stock	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Convertible Preferred Stock	Convertible Preferred Stock The Company’s Certificate of Incorporation, as amended, authorizes the Company to issue up to 100,000,000 shares of convertible preferred stock. Under the terms of the Certificate of Incorporation, the board of directors may determine the rights, preferences and terms of the Company’s authorized shares of convertible preferred stock. In connection with the consummation of the Company’s IPO in November 2016, all issued and outstanding shares of convertible preferred stock amounting to 22,471,537 shares were converted into 24,790,650 shares of common stock. As such, no convertible preferred stock shares were outstanding as of January 1, 2017 and December 31, 2017 . 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 1 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, subject to the prior rights of holders of all classes of preferred stock outstanding. The Company has never declared any dividends. The Company had reserved shares of common stock for issuance, on an as-converted basis, as follows: December 31, 2017 Options issued and outstanding 5,274,952 RSUs issued and outstanding 1,100,527 Common stock warrants 83,006 Shares available for ESPP 1,646,188 Shares available for future stock awards 2,593,201 10,697,874

Stockholders_ Equity

Stockholders’ Equity	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Stockholders' Equity	Convertible Preferred Stock The Company’s Certificate of Incorporation, as amended, authorizes the Company to issue up to 100,000,000 shares of convertible preferred stock. Under the terms of the Certificate of Incorporation, the board of directors may determine the rights, preferences and terms of the Company’s authorized shares of convertible preferred stock. In connection with the consummation of the Company’s IPO in November 2016, all issued and outstanding shares of convertible preferred stock amounting to 22,471,537 shares were converted into 24,790,650 shares of common stock. As such, no convertible preferred stock shares were outstanding as of January 1, 2017 and December 31, 2017 . 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 1 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, subject to the prior rights of holders of all classes of preferred stock outstanding. The Company has never declared any dividends. The Company had reserved shares of common stock for issuance, on an as-converted basis, as follows: December 31, 2017 Options issued and outstanding 5,274,952 RSUs issued and outstanding 1,100,527 Common stock warrants 83,006 Shares available for ESPP 1,646,188 Shares available for future stock awards 2,593,201 10,697,874

Stock-based Compensation

Stock-based Compensation	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-based Compensation	Stock-based Compensation We currently grant equity-based awards under the Company’s 2016 Omnibus Equity Incentive Plan, or the “2016 Plan”, which became effective concurrent with the completion of the Company’s IPO in November 2016. The 2016 Plan allows the Company to grant up to 4,100,000 shares of Company’s common stock with annual increase on the first day of each fiscal year beginning of January 1, 2018, equal to the lesser of (i) 3,400,000 shares, (ii) five percent of the outstanding shares of the Company’s common stock as of the last day of the immediately preceding fiscal year; or (iii) such other amounts as the board of directors may determine. The 2016 Plan provides for the grant of common stock awards, including incentive stock options, non-statutory stock options, stock appreciation rights, restricted stock and restricted stock units, performance units and performance shares to employees, directors, and consultants of the Company. All granted shares that are canceled, forfeited or expired are returned to the 2016 Plan and are available for grant in conjunction with the issuance of new equity awards. Stock options may be granted at an exercise price per share not less than 100% of the fair market value at the date of grant. If a stock option is granted to a 10% stockholder, then the exercise price per share must not be less than 110% of the fair market value per share of common stock on the grant date. Options granted are exercisable over a maximum term of 10 years from the date of grant and generally vest over a period of four years. Total stock-based compensation expense for employees and non-employees recognized in the consolidated statements of operations was as follows: Years Ended December 31, January 1, December 27, (in thousands) Cost of revenue $ 165 $ 33 $ 9 Research and development 5,616 911 302 Sales and marketing 1,763 248 445 General and administrative 3,139 1,898 446 Total stock-based compensation expense $ 10,683 $ 3,090 $ 1,202 The above stock-based compensation expense related to the following equity-based awards: Years Ended December 31, 2017 January 1, 2017 December 27, (in thousands) Stock options $ 3,539 $ 3,090 $ 1,202 RSU awards 5,368 — — ESPP shares 1,776 — — Total stock-based compensation expense $ 10,683 $ 3,090 $ 1,202 Unamortized compensation expense related to unvested stock awards was as follows (in thousands): December 31, 2017 January 1, 2017 Unamortized Expense Average Expected Recognition Period in Years Unamortized Expense Average Expected Recognition Period in Years Stock options $ 9,275 2.8 $ 5,918 3.2 RSU awards 16,272 2.7 — 0 ESPP shares 1,182 0.8 — 0 Total unamortized stock-based compensation expense $ 26,729 $ 5,918 Stock Option Activity The table below summarizes stock option activity under the 2016 Plan: Number of Number of Weighted– Weighted– Aggregate Balances at December 28, 2014 216,749 5,046,448 $ 1.55 7.4 $ 2,391 Granted (weighted–average fair value of $1.18 per share) (875,715 ) 875,715 2.71 Exercised — (121,880 ) — 1.38 Expired, forfeited or canceled 737,941 (737,941 ) 1.38 Balances at December 27, 2015 78,975 5,062,342 1.77 7.4 11,269 Authorized 6,113,092 — RSUs granted (6,950 ) — Granted (weighted–average fair value of $3.65 per share) (2,064,982 ) 2,064,982 8.99 Exercised — (403,769 ) 2.95 Expired, forfeited or canceled 249,931 (249,930 ) 3.14 Balances at January 1, 2017 4,370,066 6,473,625 3.95 7.4 91,840 Granted (weighted–average fair value of $7.91 per share) (703,283 ) 703,283 19.31 Exercised — (1,756,143 ) 1.86 Expired, forfeited or canceled 145,813 (145,813 ) 8.15 Balances at December 31, 2017 3,812,596 5,274,952 6.59 7.2 35,578 Number of Number of Weighted– Weighted– Aggregate Options vested and exercisable-December 31, 2017 2,877,479 3.26 6.1 25,963 Options vested and expected to vest-December 31, 2017 5,312,952 $ 6.60 7.2 $ 35,719 The aggregate intrinsic value of options exercised was $29.0 million , $2.6 million and $0.8 million for the years ended December 31, 2017 , January 1, 2017 and December 27, 2015 , respectively. Upon the exercise of options, the Company issues new common stock from its authorized shares. The aggregate fair value of options vested during the years ended December 31, 2017 , January 1, 2017 and December 27, 2015 was $3 million , $1.8 million , and $1.2 million , respectively. Additional information regarding options outstanding at December 31, 2017 and January 1, 2017 are as follows: December 31, 2017 Options Outstanding Options Vested Exercise Price Number of Shares Weighted- Average Remaining Contractual Life (Years) Aggregate Intrinsic Value (in thousands) Weighted- Average Exercise Price Number of Shares Aggregate Intrinsic Value (in thousands) $ 1.00 311,622 3.42 $ 3,490 $ 1.00 311,622 $ 3,490 1.50 1,065,431 4.89 11,400 1.50 1,065,431 11,400 2.00 873,091 6.90 8,906 2.00 606,164 6,183 2.50 134,000 7.35 1,300 2.50 75,620 734 3.00 435,767 7.49 4,009 3.00 199,100 1,832 4.00 64,095 8.09 526 4.00 29,361 241 5.00 75,417 8.26 543 5.00 32,260 232 7.00 11,849 8.40 62 7.00 4,965 26 8.50 1,139,604 8.52 4,217 8.50 408,500 1,511 9.00 307,173 9.00 983 9.00 98,226 314 11.43 186,533 9.96 142 11.43 — — 15.00 50,400 8.74 — 15.00 16,241 — 18.95 103,220 8.94 — 18.95 29,989 — 19.13 5,000 9.41 — 19.13 — — $ 22.18 511,750 9.12 — $ 22.18 — — 5,274,952 7.22 $ 35,578 2,877,479 $ 25,963 January 1, 2017 Options Outstanding Options Vested Exercise Price Number of Shares Weighted- Average Remaining Contractual Life (Years) Aggregate Intrinsic Value (in thousands) Weighted- Average Exercise Price Number of Shares Aggregate Intrinsic Value (in thousands) $ 1.00 927,909 4.19 $ 15,895 $ 1.00 927,909 $ 15,895 1.50 1,610,095 5.93 26,776 1.50 1,529,423 25,434 2.00 1,222,233 7.87 19,715 2.00 646,221 10,424 2.50 212,650 7.19 3,324 2.50 108,147 1,690 3.00 559,733 8.04 8,469 3.00 192,458 2,912 4.00 67,975 9.09 960 4.00 10,155 143 5.00 98,100 9.26 1,288 5.00 — — 7.00 53,700 9.40 598 7.00 1,001 11 8.50 1,209,700 9.51 11,649 8.50 152,000 1,464 9.00 325,980 9.57 2,976 9.00 — — 15.00 60,800 9.74 190 15.00 — — $ 18.95 124,750 9.94 — $ 18.95 — — 6,473,625 7.35 $ 91,840 3,567,314 $ 57,973 Stock Options Granted to Employees and Non-Employee Directors Stock-based compensation expense is based on the grant date fair value. The Company recognizes compensation expense for all stock-based awards on a straight-line basis over the requisite service period of the awards, which is generally the option vesting term of four years. The Company uses the Black-Scholes option valuation model, which requires the use of highly subjective assumptions to determine the fair value of stock-based awards. The assumptions used in the Company’s option-pricing model represent management’s best estimates. These estimates are complex, involve a number of variables, uncertainties and assumptions and the application of management’s judgment. If factors change and different assumptions are used, the Company’s stock-based compensation expense could be materially different in the future. The assumptions and estimates that the Company uses in the Black-Scholes model are as follows: • Fair Value of Common Stock . The Company determines the fair values of the shares of common stock underlying its share–based awards based upon the closing stock price on the date of grant. For all periods prior to the IPO, the fair value of common stock was determined on a periodic basis by the Company’s board of directors, with the assistance of an independent third-party valuation firm. • Risk-Free Interest Rate. The Company bases the risk-free interest rate used in the Black-Scholes valuation model on the implied yield available on U.S. Treasury zero-coupon issues with a term equivalent to that of the expected term of the options for each option group. • Expected Term. The expected term represents the period that the Company’s stock-based awards are expected to be outstanding. Because of the limitations on the sale or transfer of the Company’s common stock as a privately held company (up to November 2016), the Company does not believe its historical exercise pattern is indicative of the pattern it will experience as a publicly traded company. The Company has consequently used the Staff Accounting Bulletin 110, or SAB 110, simplified method to calculate the expected term, which is the average of the contractual term and vesting period. The Company plans to continue to use the SAB 110 simplified method until it has sufficient trading history as a publicly traded company. • Volatility. The Company determines the price volatility based on the historical volatilities of industry peers as it has insufficient trading history for its common stock price. Industry peers consist of several public companies in the semiconductor industry with comparable characteristics, including revenue growth, operating model and working capital requirements. The Company intends to continue to consistently apply this process using the same or a similar peer group of public companies until a sufficient amount of historical information regarding the volatility of its own common stock price becomes available, or unless circumstances change such that the identified peer companies are no longer similar, in which case other suitable peer companies whose common stock prices are publicly available would be utilized in the calculation. • Dividend Yield. The expected dividend assumption is based on the Company’s current expectations about its anticipated dividend policy. To date, the Company has not declared any dividends, and therefore the Company has used an expected dividend yield of zero. On January 1, 2017, the Company adopted FASB ASU 2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting . Under this guidance, the Company elected the option to no longer apply a forfeiture rate to the stock-based compensation expense, but to record forfeitures when they occur. The Company will continue to use judgment in evaluating the assumptions related to the Company’s stock-based compensation on a prospective basis. As the Company continues to accumulate additional data, it may have refinements to its estimates, which could materially impact the Company’s future stock-based compensation expense. The following assumptions were used to calculate the fair value of options granted to employees and non-employee directors during the years indicated: Years Ended December 31, January 1, December 27, Expected term (in years) 6.0 - 6.1 5.5 - 6.6 5.6 - 6.5 Volatility 37% - 39% 39% - 40% 40% - 44% Risk-free interest rate 1.9% - 2.3% 1.1 % - 2.1% 1.5% - 2.0% Expected dividend — — — 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 1/36 of the total number of shares originally granted per month for 36 months . At December 31, 2017 , 38,000 shares remained subject to the Company’s right of repurchase. The shares purchased by employees pursuant to the early exercise of stock options are not deemed, for accounting purposes, to be issued until those shares vest according to their respective vesting schedules. The cash received in exchange for unvested shares of early exercised stock options is recorded as an early exercise liability on the balance sheets and will be transferred to common stock and additional paid-in capital as such shares vest. Stock-Based Compensation for Non-employees Stock-based compensation expense related to stock awards granted to non-employee is recognized as the awards vest. The Company believes that the fair value of the stock-based awards granted is more reliably measurable than the fair value of the services received. The fair value of stock option awards granted is calculated using the Black-Scholes option valuation model. Stock-based compensation expense related to awards granted to non-employees for the years ended December 31, 2017 , January 1, 2017 and December 27, 2015 was $0.2 million , $0.8 million , and $0.4 million , respectively. The fair values of options and common stock warrants granted to non-employees were calculated using the following assumptions for the periods presented: Years Ended January 1, December 27, Contractual term remaining (in years) 1.6 - 8.3 3.4 - 10.0 Volatility 37% - 53% 36% - 48% Risk-free interest rate 0.6% - 1.7% 0.2% - 2.5% Expected dividend — — Employee Stock Purchase Plan The Company’s 2016 Employee Stock Purchase Plan (the “ESPP”) became effective in November 2016 upon the completion of the Company’s IPO. The ESPP allows eligible employees to purchase shares of the Company’s common stock at a discount through payroll deductions of up to 20% of their eligible compensation, subject to any plan limitations. The ESPP generally provides for one year offering periods with purchase periods every six months, and at the end of each purchase period, employees are able to purchase shares at 85% of the lower of the fair market value of the Company’s common stock on the first trading day of the purchase period or on the last trading day of the offering period. The Company issued 353,812 shares under the ESPP for the year ended December 31, 2017 and no shares were issued under the ESPP for the year ended January 1, 2017 . Shares authorized for future purchase under the ESPP were 1,646,188 at December 31, 2017 . Compensation expense is calculated using the fair value of the employees' purchase rights under the Black-Scholes model. The following assumptions were used in estimating the fair value of employees' purchase rights under the ESPP: Year Ended December 31, Contractual term remaining (in years) 0.5 - 1.0 Volatility 49% - 66% Risk-free interest rate 1.4 % - 1.6% Expected dividend — Restricted Stock Unit (“RSU”) Awards The Company grants RSUs to employees under the 2016 Plan and which typically vests ratably over a three to four year period, and are converted into shares of the Company’s common stock upon vesting on a one-for-one basis subject to the employee’s continued service to the Company over that period. The fair value of RSUs is determined using the fair value of the Company’s common stock on the date of the grant. Compensation expense is recognized on a straight-line basis over the requisite service period of each grant. Each RSU award granted from the 2016 Plan will reduce the number of shares available for issuance under the 2016 Plan by one share. The table below summarizes RSU activity under the 2016 Plan: Number of Weighted– Aggregate Balances at December 27, 2015 — Granted (weighted–average fair value of $18.95 per share) 6,950 Vested — Forfeited or canceled — Balances at January 1, 2017 6,950 3.9 $ 126 Granted (weighted–average fair value of $17.72 per share) 1,276,940 Vested (125,818 ) Forfeited or canceled (57,545 ) Balances at December 31, 2017 1,100,527 Outstanding and expected to vest at December 31, 2017 1,100,527 9.3 $ 13,426 At December 31, 2017 , unrecognized compensation expense related to unvested RSU awards was approximately $16.3 million . The weighted-average period over which such compensation expense will be recognized is 2.7 years. The Company did not grant any RSUs prior to fiscal year ended December 27, 2015 .

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The components of loss before income taxes were as follows: Years Ended December 31, January 1, December 27, (in thousands) United States $ 33,451 $ 16,535 $ (7,584 ) Foreign (33,981 ) (18,063 ) 654 $ (530 ) $ (1,528 ) $ (6,930 ) The components of the provision for income taxes were as follows: Years Ended December 31, January 1, December 27, (in thousands) Federal $ (290 ) $ 266 $ — State 16 1 2 Foreign 668 132 113 Total current provision for income taxes 394 399 115 Federal (35,303 ) — — State (65 ) — — Foreign 32 (32 ) — Total deferred provision (35,336 ) (32 ) — $ (34,942 ) $ 367 $ 115 The material components of the deferred tax assets were as follows: December 31, January 1, (in thousands) Deferred tax assets: Accrual, reserve and other $ 1,471 $ 2,112 Depreciation and amortization (1,625 ) (555 ) Net operating loss and credits carry forwards 48,401 59,628 Stock based compensation 1,645 535 Others 64 519 Total gross deferred tax assets 49,956 62,239 Valuation allowance (14,534 ) (62,207 ) Total net deferred tax assets $ 35,422 $ 32 A reconciliation of the Company’s effective tax rate to the statutory U.S. federal rate is as follows: Years Ended December 31, January 1, December 27, US Federal Rate 34.0 % 34.0 % 34.0 % State income taxes, net of federal benefit 867.1 — — Difference between statutory rate and foreign effective tax rate (2,285.7 ) (437.8 ) 1.7 Other permanent Items (52.3 ) (125.2 ) (0.8 ) Stock based compensation 1,650.1 (29.2 ) (2.7 ) Research and development credits 610.3 102.2 9.5 Change in valuation allowance 8,988.6 477.6 (43.4 ) Foreign Income (96.1 ) (75.8 ) — Foreign Tax Credit — 30.7 — Federal Rate Change (3,128.1 ) — — 6,587.9 % (23.5 )% (1.7 )% The reported amount of income tax expense differs from an expected amount based on statutory rates primarily due to the release of the company's valuation allowance, the change in the federal tax rate valuing the deferred tax assets, the stock compensation and the difference between the statutory rate and the foreign effective tax rate. On December 22, 2017, the U.S. government enacted comprehensive tax legislation commonly referred to as the Tax Cuts and Jobs Act (the "Tax Act"). The Tax Act makes broad and complex changes to the U.S. tax code that affect fiscal 2017, including, but not limited to requiring a one-time transition tax on certain unrepatriated earnings of foreign subsidiaries that is payable over eight years (the "Transition Tax"). The Tax Act also establishes new tax laws that will affect 2018 and later years, 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, a base erosion, anti-tax abuse tax (“BEAT”) and a deduction for foreign-derived intangible income (“FDII”) and a new provision designed to tax global intangible low-taxed income ("GILTI"). As these provisions do not apply until 2018 the Company continues to evaluate the impact of such provisions of the Tax Act. 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. 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. To the extent that a company’s accounting for certain income tax effects of the Tax Act is incomplete but it is able to determine a reasonable estimate, it must record a provisional estimate in the financial statements. Additional work is necessary for a more detailed analysis of our deferred tax assets and liabilities. Any subsequent adjustment to these amounts will be recorded to current tax expense in the quarter of 2018 when the analysis is complete. During the year ended December 31, 2017, the Company did not recognize a provisional income amount for the transition tax, due to the fact the foreign subsidiaries were in a cumulative loss. The final effects of the Tax Act may differ from these provisional amounts, due to among other things, changes in interpretations of the Tax Act, any legislative action to address questions that arise because of the Tax Act, any changes in accounting standards for income taxes or related interpretations in response to the Tax Act, any updates or changes to the estimates utilized to calculate provisional amounts, or actions we may take as a result of the Tax Act. The associated accounting for the Tax Act is expected to be completed when our 2017 US corporate income tax return is filed in 2018. In addition, the Company continues to evaluate its performance-based compensation plans within the new definitions under IRC Section 162(m) of the Internal Revenue Code. The preliminary assessment is that the Company believes that the performance based compensation provided prior to November 2, 2017 was provided pursuant to a written binding agreement and will be deductible. No further adjustment has been made at this time. The accounting for this item is incomplete and may change as our interpretation of the provisions of the Act evolve, additional information becomes available or interpretive guidance is issued by the U.S. Treasury. The associated accounting for the Tax Act is expected to be completed when our 2017 US corporate income tax return is filed in 2018. As a result of the Tax Act, the Company revalued its federal deferred tax assets based on a 21% tax rate as opposed to a 34% tax rate. The net effect of this change which is provisional, is a decrease of $16.6 million to the Company's tax benefit. A need for a valuation allowance requires an assessment of both positive and negative evidence when determining whether it is more likely than not that deferred tax assets are recoverable. Such assessment is required on a jurisdiction by jurisdiction basis. In the fourth quarter of 2017, management concluded that the valuation allowance for the Company’s US federal and state (with the exception of California) deferred tax assets is no longer needed primarily due to the emergence from cumulative losses over the previous three years. As of December 31, 2017, based on the available objective evidence, management believes it is more likely than not that the net deferred tax assets will be realized for federal and state purposes. Accordingly, management has recognized a non-recurring tax benefit of $52.5 million related to the valuation allowance reversal. As of December 31, 2017, we continued to maintain a valuation allowance of $14.5 million for California and Australia deferred tax assets until sufficient positive evidence exists to support reversal. Such assessment may change in the future as further evidence becomes available. At December 31, 2017 and January 1, 2017 , the Company has federal net operating loss carry-forwards of approximately $120.2 million and $134.1 million , respectively, and domestic state net operating loss carry-forwards of approximately $104.6 million and $104.7 million , respectively. These federal and state net operating loss carry-forwards will expire beginning in 2028 and 2017, respectively. At December 31, 2017 and January 1, 2017 , the Company also has federal research and development tax credit carry-forwards of approximately $10.6 million and $7.2 million , respectively, and domestic state research and development tax credit carry-forwards of approximately $11.0 million and $7.7 million , respectively. The federal tax credits begin to expire in 2026, and the California tax credits carry forward indefinitely. The Company's ability to utilize its net operating loss and other credit carryforwards would be subject to limitation upon a change in control. Under Internal Revenue Code Section 382, our ability to utilize NOL carry-forwards 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. During the year ended December 31, 2017 , the liability for uncertain tax positions less accrued interest and penalties increased from $5.2 million for the prior year to $5.3 million . Of the total $5.3 million of unrecognized tax benefits, $2.8 million represents the amount that if recognized, would favorably affect the effective income tax rate in any future periods. The Company cannot conclude on the range of cash payments that will be made within the next twelve months associated with its uncertain tax positions. A reconciliation of the beginning and ending unrecognized tax benefit amount is as follows: December 31, January 1, December 27, (in thousands) Beginning balance $ 5,221 $ 4,425 $ 3,738 Increases related to current year’s unrecognized tax benefits 1,569 888 687 Increases related to prior year’s unrecognized tax benefits 68 — — Decreases related to prior year’s unrecognized tax benefits (1,540 ) (92 ) — Ending balance $ 5,318 $ 5,221 $ 4,425 The Company records interest and penalties related to unrecognized tax benefits in income tax expense. For the year ended December 31, 2017 , the Company recorded no estimated interest or estimated penalties. For the period ended December 31, 2017 , no accrued interest or penalties were accrued. The Company and its subsidiaries are subject to taxation in various jurisdictions, including federal, state and foreign. The Company’s federal and state income tax returns are generally not subject to examination by taxing authorities for fiscal years before 2013 for federal purposes and 2012 for state purposes. The exceptions to this are the net operating loss carryovers and R&D credit carryovers. These amounts are subject to audit for a period of three years after utilization for federal purposes and four years after utilization for state purposes. The Company intends to reinvest the earnings of its non-U.S. subsidiaries in those operations. The Company does not provide for U.S. income taxes on the earnings of foreign subsidiaries because the Company intends to reinvest such earnings offshore indefinitely. In addition, the Company has continued to not provide for any withholding taxes or state taxes for any of the undistributed earnings of its foreign subsidiaries as of December 31, 2017.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2017
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 Internal Revenue 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 $0.5 million as of December 31, 2017 .

Segment Information and Operati

Segment Information and Operations by Geographic Area	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Segment Information and Operations by Geographic Area	Segment Information and Operations by Geographic Area The chief operating decision maker for the Company is the Chief Executive Officer. The Chief Executive Officer reviews financial information presented on a consolidated basis for purposes of allocating resources and evaluating financial performance. The Company has one business activity consisting of design, development, and marketing of advanced high-speed wireless communication solutions enabling wireless local area networking, and there are no segment managers who are held accountable for operations, operating results or plans for levels or components below the consolidated level. Accordingly, the Company has determined that it has a single reportable and operating segment structure. The following table sets forth revenue by country, based on ship-to destinations, for countries with 10% or more of revenue during any of the periods presented: Years Ended December 31, January 1, December 27, Amount % of Revenue Amount % of Revenue Amount % of Revenue (Dollars in thousands) China $ 119,821 68 % $ 86,107 66 % $ 45,102 54 % Taiwan 17,780 10 13,752 11 10,169 12 Tunisia 13,410 8 13,755 11 5,414 6 United States 283 — 291 — 3,326 4 Other foreign countries 25,065 14 15,164 12 19,762 24 Total $ 176,359 100 % $ 129,069 100 % $ 83,773 100 % Long-lived assets outside the U.S. are immaterial; therefore, disclosures have been limited to revenue.

Related Party transactions

Related Party transactions	12 Months Ended
	Dec. 31, 2017
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, is the President and Chief Executive Officer of 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. The Company incurred fees of approximately $3.0 million , $1.7 million and $1.2 million under the terms of this arrangement in fiscal years ended December 31, 2017 , January 1, 2017 and December 27, 2015 , respectively. 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 has classified the software licenses under this contract as definite long-lived intangible assets in its Condensed Consolidated Balance Sheets and which amounted to approximately $3.0 million as of December 31, 2017 , net of accumulated amortization of approximately $0.3 million . Agreement with RUSNANO Dmitry Akhanov, formerly a member of the Company’s board of directors, is President and Chief Executive Officer at Rusnano USA, Inc., a U.S. subsidiary of RUSNANO, one of the Company’s investors. In July 2014, the Company entered into an amended and restated letter agreement with RUSNANO in connection with RUSNANO’s investment in convertible promissory notes, which subsequently converted into shares of the Company’s Series G convertible preferred stock. Pursuant to the amended and restated letter agreement, the Company agreed, among other matters, to operate and fund the Company’s 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, the Company 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 December 31, 2017 , the Company had met the minimum funding requirements.

The Company and Summary of Si22

The Company and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2017
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. The fiscal years ended on December 31, 2017 , January 1, 2017 and December 27, 2015 consisted of 52 weeks, 53 weeks and 52 weeks, respectively.
Use of Estimates	Use of Estimates Preparation of financial statements in conformity with accounting principles generally accepted in the United States of America, or 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. Actual results could differ from those estimates.
Principles of Consolidation	Principles of Consolidation The consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany transactions and balances have been eliminated in consolidation.
Foreign Currency Remeasurement	Foreign Currency Remeasurement The Company and its subsidiaries use the U.S. dollar as the functional currency. Foreign currency assets and liabilities are remeasured into U.S. dollars at the end-of-period exchange rates except for non-monetary assets and liabilities, which are measured at historical exchange rates. Revenue and expenses are remeasured using an average exchange rate for the respective period, except for expenses related to non-monetary assets and liabilities, which are measured at historical exchange rates. Gains or losses from foreign currency remeasurement and transactions are included in “Other income (expense), net”.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash equivalents include liquid short-term investments with original or remaining maturities of three months or less at the date of purchase, readily convertible to known amounts of cash.
Marketable Securities	Marketable Securities Marketable securities consist primarily of highly liquid investments with maturities of greater than 90 days when purchased. We generally classify our marketable securities at the date of acquisition as available-for-sale. These securities are reported at fair value with the related unrealized gains and losses included in " Accumulated other comprehensive loss ", a component of stockholders’ equity, net of tax. Any unrealized losses which are considered to be other-than-temporary impairments are recorded in " Other income (expense), net " in the Consolidated Statements of Operations. Realized gains (losses) on the sale of marketable securities are determined using the specific-identification method and recorded in " Other income (expense), net " in the Consolidated Statements of Operations. All of our available-for-sale investments are subject to a periodic impairment review. We record a charge to earnings when a decline in fair value is significantly below cost basis and judged to be other-than-temporary, or have other indicators of impairments. If the fair value of an available-for-sale investment is less than its amortized cost basis, an other-than-temporary impairment is triggered in circumstances where (1) we intend to sell the instrument, (2) it is more likely than not that we will be required to sell the instrument before recovery of its amortized cost basis or (3) a credit loss exists where we do not expect to recover the entire amortized cost basis of the instrument. If we intend to sell or it is more likely than not that we will be required to sell the available-for-sale investment before recovery of its amortized cost basis, we recognize an other-than temporary impairment charge equal to the entire difference between the investment's amortized cost basis and its fair value.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The carrying amounts of the Company’s financial instruments, which include cash equivalents, accounts receivable, accounts payable and accrued liabilities and other current liabilities, approximate their fair values due to their short maturities. Estimates of fair value of our marketable securities are based on quoted market prices from active markets or third party, market-based pricing sources which we believe to be reliable. The estimated fair value of the Company’s debt approximates the carrying value because the interest rate on the borrowings approximates market rates and was determined to be a Level 2 instrument. The Company also has issued certain convertible preferred stock warrants which are accounted for as liabilities at fair value.
Accounts Receivable and Allowances for Doubtful Accounts	Accounts Receivable and Allowances for Doubtful Accounts Accounts receivable are stated at invoice value less estimated allowances for returns and doubtful accounts. The Company continually monitors customer payments and maintains an allowance for estimated losses resulting from its customers’ inability to make required payments. The Company considers factors such as historical experience, credit quality, age of the accounts receivable balances, geographic related risks and economic conditions that may affect a customer’s ability to pay. In cases where there are circumstances that may impair a specific customer’s ability to meet its financial obligations, a specific allowance is recorded against amounts due, which reduces the net recognized receivable to the amount reasonably believed to be collectible.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that potentially subject the Company to significant concentrations of credit risk consist principally of cash and cash equivalents, marketable securities and accounts receivable. We invest our excess cash primarily in banks, money market funds, government debt securities and corporate debt securities. We have established guidelines relative to credit ratings, diversification and maturities that seek to maintain safety and liquidity.
Restricted Cash	Restricted cash is included in Prepaid expenses and other current assets on the consolidated balance sheets.
Inventory	Inventory Inventory is stated at the lower of cost to purchase or manufacture the inventory or the market value of such inventory. Cost is determined using the standard cost method which approximates the first-in first-out basis. Market value is determined as the lower of replacement cost or net realizable value. The Company, at least quarterly, assesses the recoverability of all inventories to determine whether adjustments are required to record inventory at the lower of cost or market. Potentially excess and obsolete inventory is written off based on management’s analysis of inventory levels and estimates of future 12-month demand and market conditions. The Company is also entitled to receive rebates from its foundry partner on the purchase of silicon wafers upon achieving certain volume targets. Rebates from the Company’s foundry partner are recorded as a reduction of inventory cost when it is probable and reasonably estimable, and are recognized in cost of revenue as the chipsets made from such silicon wafers are sold to customers.
Prepaid Expenses and Other Current Assets	Prepaid Expenses and Other Current Assets The Company purchases rights to software and intellectual property used in the development of its Wi-Fi solutions. Certain of the arrangements require payment over the life of the right to use the related software and intellectual property. The Company records the up-front fees and periodic payments in prepaid expenses and other current assets and amortizes the amount over the life of the arrangement using the straight-line method.
Debt Issuance Costs and Debt Discounts	Debt Issuance Costs and Debt Discounts Costs incurred in connection with the issuance of new debt are capitalized and amounts paid in connection with the modification of existing debt are expensed as incurred. Capitalizable debt issuance costs paid to third parties and debt discounts paid to creditors, net of amortization, are recorded as a reduction to the long-term debt balance on the consolidated balance sheets. Amortization expense on capitalized debt issuance costs and debt discounts related to loans with fixed payment terms is calculated using the effective interest method over the term of the associated loans. Amortization expense on capitalized debt issuance costs and debt discounts related to revolving loans are calculated using the straight-line method over the term of the revolving loan commitment, and is recorded as Interest expense in the consolidated statements of operations. When debt is extinguished prior to the maturity date, any remaining associated debt issuance costs or debt discounts are expensed to Interest expense in the consolidated statements of operations.
Property and Equipment	Property and Equipment Property and equipment are stated at cost and depreciated using the straight‑line method over the estimated useful lives of the assets as follows: Computer and lab equipment 3 to 5 years Computer software 3 years Furniture and fixtures 3 to 7 years Leasehold improvements Shorter of remaining lease term or estimated useful lives of the assets Costs of maintenance and repairs that do not improve or extend the lives of the respective assets are expensed as incurred. Upon retirement or sale, the cost and related accumulated depreciation are removed from the consolidated balance sheets and the resulting gain or loss is reflected in operating expenses.
Intangible Assets	Intangible Assets Definite long-lived intangible assets consist of software licenses which are recorded based on the total contractual price. Such assets are amortized over its contractual lives and are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. If it is determined that such assets are not recoverable, an impairment charge is recognized for the amount by which the carrying amount of such assets exceeds their fair values.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company evaluates its long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. When the sum of the undiscounted future net cash flows expected to result from the use of the asset or asset group and its eventual disposition is less than its carrying amount, an impairment loss would be measured based on the discounted cash flows compared to the carrying amount attributable to the asset group.
Warranty	Warranty The Company provides 12 -month warranty coverage on all of its Wi-Fi solutions. The warranty provides for replacement of the associated Wi-Fi solutions during the warranty period. The Company establishes a liability for estimated warranty costs at the time revenue is recognized. The warranty obligation is affected by historical failure rates and associated replacement costs. The warranty liability is included in accrued liabilities and other current liabilities on the consolidated balance sheets.
Income Taxes	Income Taxes The Company recognizes deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements or tax returns. The Company recognizes future tax benefits, measured by enacted tax rates attributable to deductible temporary differences between financial statements and income tax bases of assets and liabilities, and net operating loss carry-forwards to the extent that realization of such benefits is more likely than not. The Company records a liability for the difference between the benefit recognized and measured pursuant to the accounting guidance on accounting for uncertain tax positions and the tax position taken or expected to be taken on the Company’s tax return. To the extent that the assessment of such tax positions changes, the change in estimate is recorded in the period in which the determination is made. The Company establishes these liabilities based on estimates of whether, and the extent to which, additional taxes will be due. These liabilities are established when the Company believes that certain positions might be challenged despite the Company’s belief that the tax return positions are fully supportable. The liabilities are adjusted in light of changing facts and circumstances, such as the outcome of tax audits.
Revenue Recognition and Deferred Revenue	Deferred Revenue Deferred revenue is comprised of billings or payments received in advance of meeting revenue recognition criteria. Revenue Recognition The Company derives a majority of its revenue from the sale of Wi-Fi solutions. Revenue is recognized net of accruals for sales returns and rebates. The Company account for rebates to end-user customers based on the maximum amount of rebate contractually due under the terms of the arrangement. Claims for customer rebates are charged to the customer rebate accrual when received and approved. Accrued customer rebates are released to revenue only at such time the rebate liability has been extinguished or is considered remote. During the fourth quarter of fiscal 2017, the Company undertook a process to confirm accrued customer rebate balances and obtain confirmation, where possible, from customers of amounts outstanding under customer rebate programs. This confirmation process provided new evidence that the probability of certain customer rebate liabilities being claimed was remote and accordingly the related accrual was reversed and recorded as revenue. The total amount of customer rebate accrual reversed and recorded in revenue during the fourth quarter of fiscal 2017 amounted to approximately $2.0 million . The Company recognizes revenue when persuasive evidence of an arrangement exists, delivery has occurred, the price is deemed fixed or determinable and collection is reasonably assured. These criteria are met upon shipment to customers. For sales made through distributors, revenue is recognized when title passes to the distributor upon shipment, and payment by the Company’s distributors is not contingent on resale of the Wi-Fi solutions. The Company’s sales arrangements with distributors do not allow for rights of return or price protection on unsold Wi-Fi solutions. The Company’s policy is to classify shipping and handling costs, net of costs charged to customers, as cost of revenue. The Company also derives revenues from contracts with multiple deliverables, including a mix of intellectual property licenses, research and development services, and other non-recurring arrangements. While licensing and non-recurring arrangements are not part of primary focus, we may enter into such arrangements on an opportunistic basis from time to time. Revenue recognition for contracts with multiple deliverables is based on the individual units of accounting determined to exist in the contract. A delivered item is considered a separate unit of accounting when (i) the delivered item has value to the customer on a stand-alone basis; and (ii) if a general right of return exists, the delivery or performance of an undelivered item is considered probable and under the Company’s control. Items are considered to have a stand-alone value when they are sold separately by any vendor or when the customer could resell the item on a stand-alone basis. In addition, intellectual property deliverables are considered to have value on a stand-alone basis if the customer could use them without the remaining elements of the arrangement. When a deliverable does not meet the criteria to be considered a separate unit of accounting, it is grouped together with other deliverables that, when combined, meet the criteria, and the appropriate allocation of arrangement consideration and revenue recognition is determined.
Research and Development Expense	Research and Development Expenses All costs related to the research and development of the Company’s Wi-Fi solutions are expensed as incurred. Research and development (“R&D”) expense consists primarily of personnel costs for the Company’s R&D activities. R&D expense also includes costs associated with the design and development of the Company’s Wi-Fi solutions, such as mask sets, prototype wafers, prototype engineering boards, software and computer-aided design software licenses, intellectual property licenses, reference design development, development testing and evaluation, depreciation and amortization expense, and allocated administrative costs.
Operating Leases	Operating Leases The Company recognizes rent expense on a straight-line basis over the non-cancellable term of the operating lease. The difference between rent expense and rent paid is recorded as deferred rent in accrued liabilities and other current liabilities on the consolidated balance sheets.
Advertising and Promotion Costs	Advertising and Promotion Costs Expenses related to advertising and promotion of products are charged to sales and marketing expense as incurred.
Stock-based Compensation	Stock-Based Compensation The Company measures and recognizes compensation expense for all stock-based awards made to employees, directors and non-employees, based on estimated fair values recognized using the straight-line method over the requisite service period. On January 1, 2017, the Company adopted the Financial Accounting Standards Board (“FASB”) Accounting Standards Update (“ASU”) 2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting . Under this guidance, the Company elected the option to no longer apply a forfeiture rate to the stock-based compensation expense, but to record forfeitures when they occur, and, as a result, under the modified retrospective method of adoption the Company recorded an immaterial cumulative effect adjustment of $54,000 to the opening accumulated deficit on January 2, 2017. The fair value of options and warrants to purchase common stock granted to employees is estimated on the grant date using the Black-Scholes option valuation model. The calculation of stock-based compensation expense requires that the Company make assumptions and judgments about the variables used in the Black-Scholes model, including the expected term, expected volatility of the underlying common stock and risk-free interest rate. The fair value for restricted stock awards is measured based on the closing market price of our common stock on the date of grant. The Company accounts for common stock warrants and options issued to non-employees under Accounting Standards Codification (“ASC”) Topic No. 505-50 Equity-Equity based payments to Non-Employees , using the Black-Scholes option valuation model. The fair value of such non-employee awards is remeasured at each quarter-end over the vesting period.
Common Stock Warrants	Common Stock Warrants The Company accounts for common stock warrants as equity in accordance with the accounting guidance for derivatives. The accounting guidance provides a scope exception from classifying and measuring as a financial liability a contract that would otherwise meet the definition of a derivative if the contract is both (i) indexed to the entity’s own stock and (ii) meets the requirement for classification in the stockholders’ equity (deficit) section of the balance sheet. The Company determined that the common stock warrants issued in connection with the debt arrangement are required to be classified in equity. Warrants classified as equity are recorded as additional paid in capital on the consolidated balance sheets in stockholders’ equity (deficit) and no further adjustments to their valuation are made. The Company accounts for common stock warrants issued to non-employees for services under ASC 505-50. The fair value of such non-employee warrants is remeasured at each quarter-end over the vesting period. The Company determines the fair value of the common stock warrants using the Black-Scholes option valuation model using the stock price and other measurement assumptions as of the earlier of the date at which either (1) a commitment for performance by the counterparty has been reached; or (2) the counterparty’s performance is complete.
Convertible Preferred Stock	Convertible Preferred Stock The Company recorded the convertible preferred stock at fair value on the dates of issuance, net of issuance costs. The convertible preferred stock is recorded outside of “Stockholders’ equity (deficit)” because, in the event of certain deemed liquidation events considered not solely within the Company’s control, such as a merger, acquisition and sale of all or substantially all of the Company’s assets, the convertible preferred stock will become redeemable at the option of the holders. The Company has not adjusted the carrying values of the convertible preferred stock to the liquidation preferences of such shares because it is uncertain whether or when an event would occur that would obligate the Company to pay the liquidation preferences to holders of shares of convertible preferred stock. Subsequent adjustments to the carrying values to the liquidation preferences will be made only when it becomes probable that such a liquidation event will occur.
Convertible Preferred Stock Warrants Liability	Convertible Preferred Stock Warrants Liability Warrants to purchase shares of convertible preferred stock are classified as liabilities on the consolidated balance sheets at fair value upon issuance because the underlying shares of convertible preferred stock are redeemable at the option of the holders upon the occurrence of certain deemed liquidation events considered not solely within the Company’s control, which may therefore obligate the Company to transfer assets at some point in the future. The convertible preferred stock warrants are subject to remeasurement to fair value at each balance sheet date and any change in fair value is recognized as a component of “Other income (expense), net” in the consolidated statements of operations.
Net Loss per Share	Net Income (Loss) per Share Basic net income (loss) per share is calculated by dividing the net income (loss) by the weighted-average number of shares of common stock outstanding during the period, without consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss by the weighted-average number of shares of common stock, without consideration for potentially dilutive securities as the inclusion of such securities would be anti-dilutive. For purposes of the diluted net loss per share calculation, unvested stock awards, warrants, convertible preferred stock and unvested employee stock purchase plan awards are considered to be potentially dilutive securities. Diluted net income per share is calculated by dividing the net income by the weighted-average number of shares of common stock and potentially dilutive securities outstanding for the period. Basic and diluted net loss per share is presented in conformity with the two-class method required for participating securities as the convertible preferred stock is considered a participating security. In addition, the Company considers shares issued upon the early exercise of non-vested warrants to purchase common stock to be participating securities, as the holders of these shares have a non-forfeitable right to dividends. 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 loss per share attributable to common stockholders. The Company’s participating securities do not have a contractual obligation to share in the Company’s losses. As such, the net loss was attributed entirely to common stockholders.
Deferred Offering Costs	Deferred Offering Costs Deferred offering costs, consisted of legal, accounting and other fees and costs related to the Company’s IPO were capitalized within “Other assets” on the consolidated balance sheets until the consummation of the IPO.
New Accounting Pronouncements	Recent Accounting Pronouncements In August 2017, the FASB issued ASU No. 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 currently does not have any hedging activities but may evaluate the effects of this standard on its consolidated financial statements in future reporting periods. In May 2017, the FASB issued ASU No. 2017-09, Compensation-Stock Compensation (Topic 718): Scope of Modification Accounting (“ASU No 2017-09”). The amendments in ASU No. 2017-09 provide guidance about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting in Topic 718. ASU No. 2017-09 is effective for the Company for annual and interim reporting periods beginning January 1, 2018. Early adoption of ASU No. 2017-09 is permitted, including adoption in any interim period, and the standard should be applied prospectively to an award modified on or after the adoption date. The adoption of this standard is not expected to have a material impact on the Company’s consolidated financial statements. In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows - Restricted Cash , which requires entities to show the changes in the total of cash, cash equivalents, restricted cash and restricted cash equivalents in the statement of cash flow. This standard is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Early adoption is permitted, including adoption in an interim period, but any adjustments must be reflected as of the beginning of the fiscal year that includes that interim period. The new standard must be adopted retrospectively. The adoption of this standard is not expected to have a material impact on the Company’s consolidated statements of cash flows. In October 2016, the FASB issued ASU No. 2016-17, Consolidation - Interests Held through Related Parties That Are under Common Control , to amend the consolidation guidance on how a reporting entity that is the single decision maker of a variable interest entity should treat indirect interests in the entity held through related parties that are under common control within the reporting entity when determining whether it is the primary beneficiary of that variable interest entity. The standard is effective for fiscal years beginning after December 15, 2016, including interim periods within those fiscal years. Early adoption is permitted. The adoption of this standard did not have a material impact on the Company’s consolidated financial position and results of operations. In October 2016, the FASB issued ASU No. 2016-16, Income Taxes - Intra-Entity Transfers of Assets Other Than Inventory , which requires entities to recognize the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. The standard is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Early adoption is permitted as of the beginning of a fiscal year. The new standard must be adopted using a modified retrospective transition method which is a cumulative-effective adjustment to retained earnings as of the beginning of the first effective reporting period. The Company is currently evaluating the effects, if any, that the adoption of this guidance will have on its consolidated financial statements. In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows - Classification of Certain Cash Receipts and Cash Payments , ASU No. 2016-15 addresses eight specific cash flow issues with the objective of reducing the existing diversity in practice in how certain cash receipts and cash payments are presented and classified in the statement of cash flows. The standard is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Early adoption is permitted, including adoption in an interim period. The adoption of this standard is not expected to have a material impact on the Company’s consolidated statements of cash flows. In February 2016, the FASB issued ASU No. 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 currently evaluating the effects, if any, that the adoption of this guidance will have on its consolidated financial statements. In January 2016, the FASB issued ASU No. 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities , which addresses certain aspects of recognition, measurement, presentation and disclosure of financial instruments. ASU No. 2016-01 is effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2017. The adoption of this standard is not expected to have a material impact on the Company’s consolidated financial statements. In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) , which supersedes the revenue recognition requirements in ASC 605, Revenue Recognition . This ASU No. 2014-09 is based on the principle that revenue is recognized to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The ASU No. 2014-09 also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments and assets recognized from costs incurred to obtain or fulfill a contract. In August 2015, FASB issued ASU No. 2015-14, Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date , which effectively delayed the adoption date by one year, to an effective date for public entities for annual and interim periods beginning after December 15, 2017. In March, April, May and December 2016, the FASB issued additional updates to the new revenue standard relating to reporting revenue on a gross versus net basis, identifying performance obligations and licensing arrangements, and narrow-scope improvements and practical expedients, respectively. The effective date of this additional update is the same as that of ASU No. 2014-09. The guidance permits the use of either a retrospective or cumulative effect transition method. The Company has determined it will implement Topic 606 using the modified retrospective transition method. The adoption of the provisions of the new standard is not expected to have a material impact on its consolidated financial position or results of operations. Based on the evaluation of its current contracts and revenue streams, under the new standard the Company has 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 will use historical data to determine an estimate of breakage which can be applied to the amount of customer rebate that is due under its contractual arrangements. The FASB has issued, and may issue in the future, interpretive guidance which may cause the Company’s evaluation to change. The Company believes it is following an appropriate timeline to allow for proper recognition, presentation and disclosure upon adoption effective the beginning of fiscal year 2018.
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 its 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 its 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 Si23

The Company and Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedules of Concentration of Risk, by Risk Factor	The following table discloses these customers’ percentage of revenue for the respective periods: Years Ended December 31, January 1, December 27, Customer A * 19% 14% B 16% 11% 15% C * 11% * D * * 11% E * * 10% ________________________ * Total customer percentage of revenue was less than 10% . At December 31, 2017 and January 1, 2017 , three and three customers accounted for 10% or more of accounts receivable, respectively as stated below: December 31, January 1, Customer A 12% 30% B 31% 12% C 14% 12% ________________________
Property, Plant and Equipment Useful Lives	Property and equipment are stated at cost and depreciated using the straight‑line method over the estimated useful lives of the assets as follows: Computer and lab equipment 3 to 5 years Computer software 3 years Furniture and fixtures 3 to 7 years Leasehold improvements Shorter of remaining lease term or estimated useful lives of the assets

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2017
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: Years Ended December 31, January 1, December 27, (in thousands, except per share data) Net income (loss) $ 34,412 $ (1,895 ) $ (7,045 ) Weighted-average shares outstanding 34,309 6,454 775 Less: weighted average shares subject to repurchase due to early exercise (50 ) (69 ) (6 ) Weighted average shares used to compute basic net income (loss) per share 34,259 6,385 769 Dilutive effect of convertible preferred stock, warrants to purchase preferred stock, stock options, common stock warrants, ESPP and RSUs 4,225 — — Weighted average shares used to compute diluted net (income) loss per share 38,484 6,385 769 Net income (loss) per share: Basic $ 1.00 $ (0.30 ) $ (9.16 ) Diluted $ 0.89 $ (0.30 ) $ (9.16 )
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: Years Ended December 31, 2017 January 1, 2017 December 27, 2015 (in thousands) Convertible preferred stock (as-converted) — — 24,791 Warrants to purchase convertible preferred stock — — 271 Warrants to purchase common stock — 477 283 Shares available for ESPP — 224 — Restricted Stock Units (RSUs) 1,095 7 — Options to purchase common stock 857 6,474 5,062 Total 1,952 7,182 30,407

Balance Sheets Components (Tabl

Balance Sheets Components (Tables)	12 Months Ended
	Dec. 31, 2017
Balance Sheets Components [Abstract]
Marketable Securities	Marketable securities at 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: December 31, January 1, (in thousands) Computer and lab equipment $ 14,295 $ 9,748 Computer software 795 625 Furniture and fixtures 1,589 136 Leasehold improvements 3,977 218 Sub-total 20,656 10,727 Accumulated depreciation and amortization (8,145 ) (5,985 ) Property and equipment, net $ 12,511 $ 4,742
Schedule of Inventory	Inventory consisted of the following: December 31, January 1, (in thousands) Raw materials $ 5,812 $ 9,067 Work in progress 1,069 1,128 Finished goods 5,781 5,625 $ 12,662 $ 15,820
Other Current Liabilities	Accrued liabilities and other current liabilities consisted of the following: December 31, January 1, (in thousands) Accrued customer rebates $ 8,710 $ 3,026 Accrued expenses 6,184 2,952 Accrued payroll and related benefits 3,411 2,842 Accrual for inventory purchases 2,124 1,353 ESPP employee contributions 706 665 Other 1,607 963 $ 22,742 $ 11,801
Schedule of Accrued Liabilities	Accrued liabilities and other current liabilities consisted of the following: December 31, January 1, (in thousands) Accrued customer rebates $ 8,710 $ 3,026 Accrued expenses 6,184 2,952 Accrued payroll and related benefits 3,411 2,842 Accrual for inventory purchases 2,124 1,353 ESPP employee contributions 706 665 Other 1,607 963 $ 22,742 $ 11,801

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2017
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 at December 31, 2017 and January 1, 2017 as follows: 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 Fair Value as of January 1, 2017 Level 1 Level 2 Level 3 Total Assets: Cash equivalents $ 100,876 $ — $ — $ 100,876
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 As of January 1, 2017 , warrants issued and outstanding were as follows: Date of Issuance Number of Warrants Exercise Price Expiration Date Common stock warrants October 2013 38,748 7.74 October 2023 Common stock warrants September 2015 283,005 2.50 February 2019 Common stock warrants February 2016 20,251 4.00 February 2019 Common stock warrants February 2016 9,000 0.05 January 2018 Common stock warrants May 2016 126,400 4.00 May 2026

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Rental Payments for Operating 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 December 31, 2017 (in thousands): 2018 $ 1,989 2019 2,269 2020 2,042 2021 1,629 2022 and beyond 3,732 Total minimum lease payments $ 11,661

Long-term Debt (Tables)

Long-term Debt (Tables)	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Schedule of Maturities of Long-term Debt	As of December 31, 2017 , there were no future minimum payments for the long-term debt as a result of the extinguishment of the term loans as of this date apart from the final payment of $3.9 million received by SVB on January 2, 2018. As of January 1, 2017 , future minimum payments for the long-term debt were as follows (in thousands): Long-term debt 2017 $ 2,570 2018 2,383 2019 1,618 Total minimum payments 6,571 Less: Amount representing interest (357 ) Less: Amount representing closing and repayment fees (330 ) Present value of minimum payments 5,884 Less: Unamortized debt discounts (167 ) Plus: Accretion of closing and repayment fees 220 Long-term debt, net 5,937 Less: Long-term debt, current portion (2,257 ) Non-current portion of long-term debt $ 3,680

Stockholders_ Equity (Tables)

Stockholders’ Equity (Tables)	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Schedule of Stock by Class	The Company had reserved shares of common stock for issuance, on an as-converted basis, as follows: December 31, 2017 Options issued and outstanding 5,274,952 RSUs issued and outstanding 1,100,527 Common stock warrants 83,006 Shares available for ESPP 1,646,188 Shares available for future stock awards 2,593,201 10,697,874

Stock-based Compensation (Table

Stock-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2017
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 consolidated statements of operations was as follows: Years Ended December 31, January 1, December 27, (in thousands) Cost of revenue $ 165 $ 33 $ 9 Research and development 5,616 911 302 Sales and marketing 1,763 248 445 General and administrative 3,139 1,898 446 Total stock-based compensation expense $ 10,683 $ 3,090 $ 1,202 The above stock-based compensation expense related to the following equity-based awards: Years Ended December 31, 2017 January 1, 2017 December 27, (in thousands) Stock options $ 3,539 $ 3,090 $ 1,202 RSU awards 5,368 — — ESPP shares 1,776 — — Total stock-based compensation expense $ 10,683 $ 3,090 $ 1,202
Schedule of Unrecognized Compensation Cost, Nonvested Awards	Unamortized compensation expense related to unvested stock awards was as follows (in thousands): December 31, 2017 January 1, 2017 Unamortized Expense Average Expected Recognition Period in Years Unamortized Expense Average Expected Recognition Period in Years Stock options $ 9,275 2.8 $ 5,918 3.2 RSU awards 16,272 2.7 — 0 ESPP shares 1,182 0.8 — 0 Total unamortized stock-based compensation expense $ 26,729 $ 5,918
Schedule of Share-based Compensation, Stock Options, Activity	The table below summarizes stock option activity under the 2016 Plan: Number of Number of Weighted– Weighted– Aggregate Balances at December 28, 2014 216,749 5,046,448 $ 1.55 7.4 $ 2,391 Granted (weighted–average fair value of $1.18 per share) (875,715 ) 875,715 2.71 Exercised — (121,880 ) — 1.38 Expired, forfeited or canceled 737,941 (737,941 ) 1.38 Balances at December 27, 2015 78,975 5,062,342 1.77 7.4 11,269 Authorized 6,113,092 — RSUs granted (6,950 ) — Granted (weighted–average fair value of $3.65 per share) (2,064,982 ) 2,064,982 8.99 Exercised — (403,769 ) 2.95 Expired, forfeited or canceled 249,931 (249,930 ) 3.14 Balances at January 1, 2017 4,370,066 6,473,625 3.95 7.4 91,840 Granted (weighted–average fair value of $7.91 per share) (703,283 ) 703,283 19.31 Exercised — (1,756,143 ) 1.86 Expired, forfeited or canceled 145,813 (145,813 ) 8.15 Balances at December 31, 2017 3,812,596 5,274,952 6.59 7.2 35,578 Number of Number of Weighted– Weighted– Aggregate Options vested and exercisable-December 31, 2017 2,877,479 3.26 6.1 25,963 Options vested and expected to vest-December 31, 2017 5,312,952 $ 6.60 7.2 $ 35,719
Schedule of Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding	Additional information regarding options outstanding at December 31, 2017 and January 1, 2017 are as follows: December 31, 2017 Options Outstanding Options Vested Exercise Price Number of Shares Weighted- Average Remaining Contractual Life (Years) Aggregate Intrinsic Value (in thousands) Weighted- Average Exercise Price Number of Shares Aggregate Intrinsic Value (in thousands) $ 1.00 311,622 3.42 $ 3,490 $ 1.00 311,622 $ 3,490 1.50 1,065,431 4.89 11,400 1.50 1,065,431 11,400 2.00 873,091 6.90 8,906 2.00 606,164 6,183 2.50 134,000 7.35 1,300 2.50 75,620 734 3.00 435,767 7.49 4,009 3.00 199,100 1,832 4.00 64,095 8.09 526 4.00 29,361 241 5.00 75,417 8.26 543 5.00 32,260 232 7.00 11,849 8.40 62 7.00 4,965 26 8.50 1,139,604 8.52 4,217 8.50 408,500 1,511 9.00 307,173 9.00 983 9.00 98,226 314 11.43 186,533 9.96 142 11.43 — — 15.00 50,400 8.74 — 15.00 16,241 — 18.95 103,220 8.94 — 18.95 29,989 — 19.13 5,000 9.41 — 19.13 — — $ 22.18 511,750 9.12 — $ 22.18 — — 5,274,952 7.22 $ 35,578 2,877,479 $ 25,963 January 1, 2017 Options Outstanding Options Vested Exercise Price Number of Shares Weighted- Average Remaining Contractual Life (Years) Aggregate Intrinsic Value (in thousands) Weighted- Average Exercise Price Number of Shares Aggregate Intrinsic Value (in thousands) $ 1.00 927,909 4.19 $ 15,895 $ 1.00 927,909 $ 15,895 1.50 1,610,095 5.93 26,776 1.50 1,529,423 25,434 2.00 1,222,233 7.87 19,715 2.00 646,221 10,424 2.50 212,650 7.19 3,324 2.50 108,147 1,690 3.00 559,733 8.04 8,469 3.00 192,458 2,912 4.00 67,975 9.09 960 4.00 10,155 143 5.00 98,100 9.26 1,288 5.00 — — 7.00 53,700 9.40 598 7.00 1,001 11 8.50 1,209,700 9.51 11,649 8.50 152,000 1,464 9.00 325,980 9.57 2,976 9.00 — — 15.00 60,800 9.74 190 15.00 — — $ 18.95 124,750 9.94 — $ 18.95 — — 6,473,625 7.35 $ 91,840 3,567,314 $ 57,973
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions	The following assumptions were used to calculate the fair value of options granted to employees and non-employee directors during the years indicated: Years Ended December 31, January 1, December 27, Expected term (in years) 6.0 - 6.1 5.5 - 6.6 5.6 - 6.5 Volatility 37% - 39% 39% - 40% 40% - 44% Risk-free interest rate 1.9% - 2.3% 1.1 % - 2.1% 1.5% - 2.0% Expected dividend — — — The fair values of options and common stock warrants granted to non-employees were calculated using the following assumptions for the periods presented: Years Ended January 1, December 27, Contractual term remaining (in years) 1.6 - 8.3 3.4 - 10.0 Volatility 37% - 53% 36% - 48% Risk-free interest rate 0.6% - 1.7% 0.2% - 2.5% Expected dividend — — The following assumptions were used in estimating the fair value of employees' purchase rights under the ESPP: Year Ended December 31, Contractual term remaining (in years) 0.5 - 1.0 Volatility 49% - 66% Risk-free interest rate 1.4 % - 1.6% Expected dividend —
Schedule of Share-based Compensation, Restricted Stock Units Award Activity	The table below summarizes RSU activity under the 2016 Plan: Number of Weighted– Aggregate Balances at December 27, 2015 — Granted (weighted–average fair value of $18.95 per share) 6,950 Vested — Forfeited or canceled — Balances at January 1, 2017 6,950 3.9 $ 126 Granted (weighted–average fair value of $17.72 per share) 1,276,940 Vested (125,818 ) Forfeited or canceled (57,545 ) Balances at December 31, 2017 1,100,527 Outstanding and expected to vest at December 31, 2017 1,100,527 9.3 $ 13,426

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Schedule of Income before Income Tax, Domestic and Foreign	The components of loss before income taxes were as follows: Years Ended December 31, January 1, December 27, (in thousands) United States $ 33,451 $ 16,535 $ (7,584 ) Foreign (33,981 ) (18,063 ) 654 $ (530 ) $ (1,528 ) $ (6,930 )
Schedule of Components of Income Tax Expense (Benefit)	The components of the provision for income taxes were as follows: Years Ended December 31, January 1, December 27, (in thousands) Federal $ (290 ) $ 266 $ — State 16 1 2 Foreign 668 132 113 Total current provision for income taxes 394 399 115 Federal (35,303 ) — — State (65 ) — — Foreign 32 (32 ) — Total deferred provision (35,336 ) (32 ) — $ (34,942 ) $ 367 $ 115
Schedule of Deferred Tax Assets and Liabilities	The material components of the deferred tax assets were as follows: December 31, January 1, (in thousands) Deferred tax assets: Accrual, reserve and other $ 1,471 $ 2,112 Depreciation and amortization (1,625 ) (555 ) Net operating loss and credits carry forwards 48,401 59,628 Stock based compensation 1,645 535 Others 64 519 Total gross deferred tax assets 49,956 62,239 Valuation allowance (14,534 ) (62,207 ) Total net deferred tax assets $ 35,422 $ 32
Schedule of Effective Income Tax Rate Reconciliation	A reconciliation of the Company’s effective tax rate to the statutory U.S. federal rate is as follows: Years Ended December 31, January 1, December 27, US Federal Rate 34.0 % 34.0 % 34.0 % State income taxes, net of federal benefit 867.1 — — Difference between statutory rate and foreign effective tax rate (2,285.7 ) (437.8 ) 1.7 Other permanent Items (52.3 ) (125.2 ) (0.8 ) Stock based compensation 1,650.1 (29.2 ) (2.7 ) Research and development credits 610.3 102.2 9.5 Change in valuation allowance 8,988.6 477.6 (43.4 ) Foreign Income (96.1 ) (75.8 ) — Foreign Tax Credit — 30.7 — Federal Rate Change (3,128.1 ) — — 6,587.9 % (23.5 )% (1.7 )%
Unrecognized Tax Benefits	A reconciliation of the beginning and ending unrecognized tax benefit amount is as follows: December 31, January 1, December 27, (in thousands) Beginning balance $ 5,221 $ 4,425 $ 3,738 Increases related to current year’s unrecognized tax benefits 1,569 888 687 Increases related to prior year’s unrecognized tax benefits 68 — — Decreases related to prior year’s unrecognized tax benefits (1,540 ) (92 ) — Ending balance $ 5,318 $ 5,221 $ 4,425

Segment Information and Opera32

Segment Information and Operations by Geographic Area (Tables)	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Schedule of Revenue from External Customers by Geographical Areas	The following table sets forth revenue by country, based on ship-to destinations, for countries with 10% or more of revenue during any of the periods presented: Years Ended December 31, January 1, December 27, Amount % of Revenue Amount % of Revenue Amount % of Revenue (Dollars in thousands) China $ 119,821 68 % $ 86,107 66 % $ 45,102 54 % Taiwan 17,780 10 13,752 11 10,169 12 Tunisia 13,410 8 13,755 11 5,414 6 United States 283 — 291 — 3,326 4 Other foreign countries 25,065 14 15,164 12 19,762 24 Total $ 176,359 100 % $ 129,069 100 % $ 83,773 100 %

The Company and Summary of Si33

The Company and Summary of Significant Accounting Policies (Narrative) (Details)	Sep. 29, 2017USD ($)	Oct. 13, 2016	Nov. 25, 2016USD ($)shares	Dec. 31, 2017USD ($)	Dec. 31, 2017USD ($)	Jan. 01, 2017USD ($)	Dec. 27, 2015USD ($)	Jan. 02, 2017USD ($)	Oct. 27, 2016$ / shares
Subsidiary, Sale of Stock [Line Items]
Restricted cash				$ 59,000	$ 59,000	$ 59,000,000
Intangible asset				2,987,000	$ 2,987,000
Warranty period					12 months
Customer discounts and rebates				$ 2,000,000
Revenue					$ 176,359,000	129,069,000	$ 83,773,000
Stock split conversion ratio		0.02
IPO
Subsidiary, Sale of Stock [Line Items]
Sale of stock price (USD per share) | $ / shares									$ 16
Number of shares issued (in shares) | shares			6,775,466
Consideration received			$ 97,400,000
IPO | Underwriters
Subsidiary, Sale of Stock [Line Items]
Number of shares issued (in shares) | shares			75,466
Adoption of ASU 2016-09
Subsidiary, Sale of Stock [Line Items]
Deferred income tax liabilities, net								$ (54,000,000)
Adoption of ASU 2016-09 | Accumulated Deficit
Subsidiary, Sale of Stock [Line Items]
Cumulative effect of new accounting principle in period of adoption								$ 54,000
Software License Arrangement
Subsidiary, Sale of Stock [Line Items]
Amortization of intangible assets	$ 300,000
Revenue					$ 16,500,000	$ 500,000	$ 5,700,000

The Company and Summary of Si34

The Company and Summary of Significant Accounting Policies (Concentration Risk) (Details) - Customer Concentration Risk	12 Months Ended
	Dec. 31, 2017	Jan. 01, 2017	Dec. 27, 2015
A | Sales Revenue, Services, Net
Concentration Risk [Line Items]
Concentration risk rate		19.00%	14.00%
A | Accounts Receivable
Concentration Risk [Line Items]
Concentration risk rate	12.00%	30.00%
B | Sales Revenue, Services, Net
Concentration Risk [Line Items]
Concentration risk rate	16.00%	11.00%	15.00%
B | Accounts Receivable
Concentration Risk [Line Items]
Concentration risk rate	31.00%	12.00%
C | Sales Revenue, Services, Net
Concentration Risk [Line Items]
Concentration risk rate		11.00%
C | Accounts Receivable
Concentration Risk [Line Items]
Concentration risk rate	14.00%	12.00%
D | Sales Revenue, Services, Net
Concentration Risk [Line Items]
Concentration risk rate			11.00%
E | Sales Revenue, Services, Net
Concentration Risk [Line Items]
Concentration risk rate			10.00%

The Company and Summary of Si35

The Company and Summary of Significant Accounting Policies (Property and Equipment Useful Lives) (Details)	12 Months Ended
	Dec. 31, 2017
Computer software
Property, Plant and Equipment [Line Items]
Useful life	3 years
Minimum | Computer and lab equipment
Property, Plant and Equipment [Line Items]
Useful life	3 years
Minimum | Furniture and fixtures
Property, Plant and Equipment [Line Items]
Useful life	3 years
Maximum | Computer and lab equipment
Property, Plant and Equipment [Line Items]
Useful life	5 years
Maximum | Furniture and fixtures
Property, Plant and Equipment [Line Items]
Useful life	7 years

Earnings Per Share (Schedule of

Earnings Per Share (Schedule of Eanings Per Share) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Jan. 01, 2017	Dec. 27, 2015
Earnings Per Share [Abstract]
Net income (loss)	$ 34,412	$ (1,895)	$ (7,045)
Weighted-average shares outstanding (in shares)	34,309,000	6,454,000	775,000
Less: weighted average shares subject to repurchase due to early exercise (in shares)	(50,000)	(69,000)	(6,000)
Weighted average shares used to compute basic net income (loss) per share (in shares)	34,259,000	6,385,000	769,000
Dilutive effect of convertible preferred stock, warrants to purchase preferred stock, stock options, common stock warrants, ESPP and RSUs (in shares)	4,225,000	0	0
Weighted average shares used to compute diluted net (income) loss per share (in shares)	38,484,000	6,385,000	769,000
Net income (loss) per share:
Basic (dollars per share)	$ 1	$ (0.30)	$ (9.16)
Diluted (dollars per share)	$ 0.89	$ (0.30)	$ (9.16)

Earnings Per Share (Schedule 37

Earnings Per Share (Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share) (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2017	Jan. 01, 2017	Dec. 27, 2015
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation (in shares)	1,952	7,182	30,407
Convertible preferred stock (as-converted)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation (in shares)	0	0	24,791
Warrants to purchase convertible preferred stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation (in shares)	0	0	271
Warrants to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation (in shares)	0	477	283
Shares available for ESPP
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation (in shares)	0	224	0
Restricted Stock Units (RSUs)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation (in shares)	1,095	7	0
Options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation (in shares)	857	6,474	5,062

Balance Sheets Components (Mark

Balance Sheets Components (Marketable Securities) (Details) $ in Thousands	Dec. 31, 2017USD ($)
Schedule of Investments [Line Items]
Amortized Cost	$ 94,459
Gross Unrealized Gains	7
Gross Unrealized Losses	(271)
Fair Value	94,195
Corporate debt securities
Schedule of Investments [Line Items]
Amortized Cost	83,570
Gross Unrealized Gains	7
Gross Unrealized Losses	(250)
Fair Value	83,327
Government debt securities
Schedule of Investments [Line Items]
Amortized Cost	10,889
Gross Unrealized Gains	0
Gross Unrealized Losses	(21)
Fair Value	$ 10,868

Balance Sheets Components (Amor

Balance Sheets Components (Amortized Cost and Fair Value) (Details) $ in Thousands	Dec. 31, 2017USD ($)
Amortized Cost
Due in one year or less	$ 49,201
Due after one year to five years	45,258
Total, amortized cost basis	94,459
Fair Value
Due in one year or less	49,144
Due after one year to five years	45,051
Total, fair value	$ 94,195

Balance Sheets Components (Sche

Balance Sheets Components (Schedule of Property and Equipment) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Jan. 01, 2017	Dec. 27, 2015
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 20,656	$ 10,727
Accumulated depreciation and amortization	(8,145)	(5,985)
Property and equipment, net	12,511	4,742
Depreciation and amortization	2,669	1,278	$ 987
Computer and lab equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	14,295	9,748
Computer software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	795	625
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,589	136
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 3,977	$ 218

Balance Sheets Components (Sc41

Balance Sheets Components (Schedule of Inventory) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Jan. 01, 2017
Balance Sheets Components [Abstract]
Raw materials	$ 5,812	$ 9,067
Work in progress	1,069	1,128
Finished goods	5,781	5,625
Inventory, gross	$ 12,662	$ 15,820

Balance Sheets Components (Accr

Balance Sheets Components (Accrued Liabilities and Other Current Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Jan. 01, 2017
Balance Sheets Components [Abstract]
Accrued customer rebates	$ 8,710	$ 3,026
Accrued expenses	6,184	2,952
Accrued payroll and related benefits	3,411	2,842
Accrual for inventory purchases	2,124	1,353
ESPP employee contributions	706	665
Other	1,607	963
Accrued liabilities and other current liabilities	$ 22,742	$ 11,801

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Details)	Dec. 31, 2017$ / shares
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value assumption (usd per share)	$ 1

Fair Value Measurements (Assets

Fair Value Measurements (Assets, Recurring Basis) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Jan. 01, 2017
Assets:
Cash equivalents	$ 0
Fair Value, Measurements, Recurring
Assets:
Cash equivalents	6,398	$ 100,876
Marketable securities	94,195
Total cash equivalents and marketable securities	100,593
Fair Value, Measurements, Recurring | Level 1
Assets:
Cash equivalents	4,398	100,876
Marketable securities	0
Total cash equivalents and marketable securities	4,398
Fair Value, Measurements, Recurring | Level 2
Assets:
Cash equivalents	2,000	0
Marketable securities	94,195
Total cash equivalents and marketable securities	96,195
Fair Value, Measurements, Recurring | Level 3
Assets:
Cash equivalents		$ 0
Marketable securities	0
Total cash equivalents and marketable securities	0
Money market funds | Fair Value, Measurements, Recurring
Assets:
Cash equivalents	4,398
Money market funds | Fair Value, Measurements, Recurring | Level 1
Assets:
Cash equivalents	4,398
Money market funds | Fair Value, Measurements, Recurring | Level 2
Assets:
Cash equivalents	0
Money market funds | Fair Value, Measurements, Recurring | Level 3
Assets:
Cash equivalents	0
Corporate debt securities | Fair Value, Measurements, Recurring
Assets:
Cash equivalents	2,000
Marketable securities	83,329
Corporate debt securities | Fair Value, Measurements, Recurring | Level 1
Assets:
Cash equivalents	0
Marketable securities	0
Corporate debt securities | Fair Value, Measurements, Recurring | Level 2
Assets:
Cash equivalents	2,000
Marketable securities	83,329
Corporate debt securities | Fair Value, Measurements, Recurring | Level 3
Assets:
Cash equivalents	0
Marketable securities	0
Government debt securities | Fair Value, Measurements, Recurring
Assets:
Marketable securities	10,866
Government debt securities | Fair Value, Measurements, Recurring | Level 1
Assets:
Marketable securities	0
Government debt securities | Fair Value, Measurements, Recurring | Level 2
Assets:
Marketable securities	10,866
Government debt securities | Fair Value, Measurements, Recurring | Level 3
Assets:
Marketable securities	$ 0

Fair Value Measurements (Common

Fair Value Measurements (Common Stock Warrants) (Details) - $ / shares	Dec. 31, 2017	Jan. 01, 2017
Class of Warrant or Right [Line Items]
Number of Warrants (in shares)	83,006
September 2,015
Class of Warrant or Right [Line Items]
Number of Warrants (in shares)	83,006	283,005
Number of Warrants Issued (in shares)	83,006	283,005
Exercise Price (usd per share)	$ 2.50	$ 2.50
October 2,013
Class of Warrant or Right [Line Items]
Number of Warrants (in shares)		38,748
Number of Warrants Issued (in shares)		38,747.5
Exercise Price (usd per share)	7.74	$ 7.74
February 2,016
Class of Warrant or Right [Line Items]
Number of Warrants (in shares)		20,251
Number of Warrants Issued (in shares)		20,251
Exercise Price (usd per share)	4	$ 4
February 2,016
Class of Warrant or Right [Line Items]
Number of Warrants (in shares)		9,000
Number of Warrants Issued (in shares)		9,000
Exercise Price (usd per share)	0.05	$ 0.05
May 2,016
Class of Warrant or Right [Line Items]
Number of Warrants (in shares)		126,400
Number of Warrants Issued (in shares)		126,400
Exercise Price (usd per share)	$ 4	$ 4

Commitments and Contingencies46

Commitments and Contingencies (Details) $ in Thousands	Dec. 31, 2017USD ($)
Commitments and Contingencies Disclosure [Abstract]
2,018	$ 1,989
2,019	2,269
2,020	2,042
2,021	1,629
2022 and beyond	3,732
Total minimum lease payments	$ 11,661

Commitments and Contingencies47

Commitments and Contingencies (Narrative) (Details) ft² in Thousands	1 Months Ended	12 Months Ended
	Feb. 28, 2017ft²	Dec. 31, 2017USD ($)	Jan. 01, 2017USD ($)	Dec. 27, 2015USD ($)
Other Commitments [Line Items]
Rent expense		$ 1,900,000	$ 1,200,000	$ 1,200,000
Area of real estate property | ft²	84
Term of lease	76 months
Purchase obligation		37,200,000
Indemnification Agreement
Other Commitments [Line Items]
Guarantor obligations		$ 0

Commitments and Contingencies48

Commitments and Contingencies (RUSNANO) (Details) - Investor - Agreement with RUSNANO $ in Millions	Dec. 31, 2014period	Jul. 31, 2014USD ($)period
Related Party Transaction [Line Items]
Contractual obligation		$ 13
Annual periods | period	6	6
Contractual obligation, year 1		$ 2.2
Contractual obligation, year 2		1.7
Contractual obligation, year 3		2
Contractual obligation, year 4		2.2
Contractual obligation, year 5		2.4
Contractual obligation, year 6		$ 2.5
Funding obligation penalty		10.00%
Difference between the funding obligation and the actual funding		80.00%

Commitments and Contingencies49

Commitments and Contingencies (Narrative 2) (Details) - Software License Arrangement $ in Millions	Dec. 31, 2017USD ($)
Other Commitments [Line Items]
Contractual obligation	$ 4.1
Contractual obligation, year 1	1.5
Contractual obligation, year 2	$ 2.6

Commitments and Contingencies50

Commitments and Contingencies (Legal Matters) (Details)	1 Months Ended
	Oct. 31, 2016patent
Commitments and Contingencies Disclosure [Abstract]
Number of Expired Patents	9

Long-term Debt (Details)

Long-term Debt (Details) - USD ($) $ in Thousands	Jan. 02, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Debt payable		$ 3,943
Loans Payable
Debt Instrument [Line Items]
Basis spread on variable rate		0.75%
Revolving Credit Facility
Debt Instrument [Line Items]
Remaining borrowing capacity		$ 20,000
Eligible accounts receivable percentage, maximum draw of credit line		80.00%
Revolving Credit Facility | Minimum
Debt Instrument [Line Items]
Line of credit interest rate during period		4.25%
Revolving Credit Facility | Maximum
Debt Instrument [Line Items]
Line of credit interest rate during period		5.00%
Subsequent Event
Debt Instrument [Line Items]
Repayments of debt	$ 3,900

Long-term Debt (Schedule of Mat

Long-term Debt (Schedule of Maturities of Long-term Debt) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Jan. 01, 2017
Debt Disclosure [Abstract]
2,017		$ 2,570
2,018		2,383
2,019		1,618
Total minimum payments		6,571
Less: Amount representing interest		(357)
Less: Amount representing closing and repayment fees		(330)
Present value of minimum payments		5,884
Less: Unamortized debt discounts		(167)
Plus: Accretion of closing and repayment fees		220
Long-term debt, net		5,937
Less: Long-term debt, current portion	$ (3,943)	(2,257)
Long-term debt	$ 0	$ 3,680

Convertible Preferred Stock (De

Convertible Preferred Stock (Details) - shares	1 Months Ended	12 Months Ended
	Nov. 30, 2016	Jan. 01, 2017	Dec. 31, 2017
Convertible Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)	100,000,000
Preferred stock, shares outstanding (in shares)	22,471,537	0	0
Conversion of preferred stock to common stock pursuant to IPO (in shares)		(22,471,537)
Common Stock
Class of Stock [Line Items]
Conversion of preferred stock to common stock pursuant to IPO (in shares)	24,790,650	24,790,650

Stockholders_ Equity (Details)

Stockholders’ Equity (Details)	Dec. 31, 2017vote$ / sharesshares	Jan. 01, 2017$ / sharesshares
Equity [Abstract]
Common stock, shares authorized (in shares)	1,000,000,000	1,000,000,000
Common stock, par value (in usd per share) | $ / shares	$ 0.0001	$ 0.0001
Votes per share | vote	1
Options issued and outstanding	5,274,952
RSUs issued and outstanding	1,100,527
Common stock warrants	83,006
Shares available for ESPP	1,646,188
Shares available for future stock awards	2,593,201
Shares reserved for future issuance (in shares)	10,697,874

Stock-based Compensation (Narra

Stock-based Compensation (Narrative) (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Nov. 30, 2016shares	Dec. 31, 2017USD ($)shares	Jan. 01, 2017USD ($)shares	Dec. 27, 2015USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future grants (in shares)		2,593,201
Vesting period		4 years
Aggregate intrinsic value of options exercised | $		$ 29,000	$ 2,600	$ 800
Aggregate fair value of options vested | $		$ 3,000	1,800	1,200
Repurchase rights expiration per month of shares		0.0278
Expiration period of repurchase program		36 months
Remaining number of shares authorized to be repurchased (in shares)		38,000
Share-based compensation to non-employees | $		$ 200	$ 800	$ 400
Average recognition period for cost not yet recognized		2 years 9 months 6 days	3 years 2 months 6 days
ESPP shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unamortized expense | $			$ 0
Average recognition period for cost not yet recognized			0 years
2016 Employee Stock Purchase Plan | ESPP shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future grants (in shares)	4,100,000
Conditional increase of shares (in shares)	3,400,000
Conditional increase of shares rate	5.00%
Exercisable term		10 years
Vesting period		4 years
Maximum subscription rate		20.00%
Stock issued (in shares)		353,812	0
Stock authorized for repurchase (in shares)		1,646,188
Unamortized expense | $		$ 1,182
Average recognition period for cost not yet recognized		9 months 6 days

Stock-based Compensation (Compe

Stock-based Compensation (Compensation Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Jan. 01, 2017	Dec. 27, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 10,683	$ 3,090	$ 1,202
Cost of revenue
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	165	33	9
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	5,616	911	302
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	1,763	248	445
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 3,139	$ 1,898	$ 446

Stock-based Compensation (Equit

Stock-based Compensation (Equity Based Awards Compensation Costs) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Jan. 01, 2017	Dec. 27, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 10,683	$ 3,090	$ 1,202
Stock options
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	3,539	3,090	1,202
RSU awards
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	5,368	0	0
ESPP shares
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 1,776	$ 0	$ 0

Stock-based Compensation (Sched

Stock-based Compensation (Schedule of Unrecognized Compensation Cost, Nonvested Awards) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Jan. 01, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unamortized Expense, Stock options	$ 9,275	$ 5,918
Total unamortized stock-based compensation expense	$ 26,729	$ 5,918
Average Expected Recognition Period in Years	2 years 9 months 6 days	3 years 2 months 6 days
RSU awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unamortized Expense	$ 16,272	$ 0
Average Expected Recognition Period in Years	2 years 8 months 6 days	0 years
ESPP shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unamortized Expense		$ 0
Average Expected Recognition Period in Years		0 years

Stock-based Compensation (Sch59

Stock-based Compensation (Schedule of Share-based Compensation, Stock Options, Activity) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Jan. 01, 2017	Dec. 27, 2015	Dec. 28, 2014
Number of Shares Available for Issuance
Ending balance (in shares)	2,593,201
Number of Shares Outstanding
Ending balance (in shares)	5,274,952
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Aggregate intrinsic value	$ 35,578	$ 91,840
Aggregate intrinsic value, options vested and expected to vest	$ 25,963	$ 57,973
Weighted average fair value (usd per share)	$ 7.91	$ 3.65	$ 1.18
Stock options
Number of Shares Available for Issuance
Beginning balance (in shares)	4,370,066	78,975	216,749
Authorized (in shares)			6,113,092
Granted (in shares)	(703,283)	(2,064,982)	(875,715)
Expired, forfeited or canceled (in shares)	145,813	249,931	737,941
Ending balance (in shares)	3,812,596	4,370,066	78,975	216,749
Number of Shares Outstanding
Beginning balance (in shares)	6,473,625	5,062,342	5,046,448
Granted (in shares)	703,283	2,064,982	875,715
Exercised (in shares)	(1,756,143)	(403,769)	(121,880)
Expired, forfeited or canceled (in shares)	(145,813)	(249,930)	(737,941)
Ending balance (in shares)	5,274,952	6,473,625	5,062,342	5,046,448
Options vested and exercisable-December 31, 2017	2,877,479
Options vested and expected to vest-December 31, 2017	5,312,952
Weighted– Average Exercise Price
Beginning balance (usd per share)	$ 3.95	$ 1.77	$ 1.55
Granted (usd per share)	19.31	8.99	2.71
Exercised (usd per share)	1.86	2.95	1.38
Expired, forfeited or canceled (usd per share)	8.15	3.14	1.38
Ending balance (usd per share)	6.59	$ 3.95	$ 1.77	$ 1.55
Options Exercisable-December 31, 2017 (usd per share)	3.26
Options vested and expected to vest-December 31, 2017 (usd per share)	$ 6.60
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted-average remaining contractual term	7 years 2 months 6 days	7 years 4 months 8 days	7 years 4 months 8 days	7 years 4 months 8 days
Weighted-average remaining contractual term, Options Exercisable	6 years 1 month 6 days
Weighted-average remaining contractual term, Options vested and expected to vest	7 years 2 months 6 days
Aggregate intrinsic value	$ 35,578	$ 91,840	$ 11,269	$ 2,391
Aggregate intrinsic value, options exercisable	25,963
Aggregate intrinsic value, options vested and expected to vest	$ 35,719
Restricted Stock Units (RSUs)
Number of Shares Available for Issuance
Granted (in shares)	1,276,940	6,950

Stock-based Compensation (Optio

Stock-based Compensation (Options Outstanding and Options Vested) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Jan. 01, 2017
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of options outstanding(in shares)	5,274,952	6,473,625
Weighted average remaining contractual life	7 years 2 months 18 days	7 years 4 months 6 days
Aggregate intrinsic value	$ 35,578	$ 91,840
Number of options vested (in shares)	2,877,479	3,567,314
Aggregate intrinsic value, options vested	$ 25,963	$ 57,973
$ 1
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price (usd per share)	$ 1	$ 1
Number of options outstanding(in shares)	311,622	927,909
Weighted average remaining contractual life	3 years 5 months 2 days	4 years 2 months 9 days
Aggregate intrinsic value	$ 3,490	$ 15,895
Weighted average exercise price, options vested (usd per share)	$ 1	$ 1
Number of options vested (in shares)	311,622	927,909
Aggregate intrinsic value, options vested	$ 3,490	$ 15,895
$ 1.50
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price (usd per share)	$ 1.50	$ 1.50
Number of options outstanding(in shares)	1,065,431	1,610,095
Weighted average remaining contractual life	4 years 10 months 19 days	5 years 11 months 5 days
Aggregate intrinsic value	$ 11,400	$ 26,776
Weighted average exercise price, options vested (usd per share)	$ 1.50	$ 1.50
Number of options vested (in shares)	1,065,431	1,529,423
Aggregate intrinsic value, options vested	$ 11,400	$ 25,434
$ 2
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price (usd per share)	$ 2	$ 2
Number of options outstanding(in shares)	873,091	1,222,233
Weighted average remaining contractual life	6 years 10 months 24 days	7 years 10 months 13 days
Aggregate intrinsic value	$ 8,906	$ 19,715
Weighted average exercise price, options vested (usd per share)	$ 2	$ 2
Number of options vested (in shares)	606,164	646,221
Aggregate intrinsic value, options vested	$ 6,183	$ 10,424
$ 2.50
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price (usd per share)	$ 2.50	$ 2.50
Number of options outstanding(in shares)	134,000	212,650
Weighted average remaining contractual life	7 years 4 months 6 days	7 years 2 months 9 days
Aggregate intrinsic value	$ 1,300	$ 3,324
Weighted average exercise price, options vested (usd per share)	$ 2.50	$ 2.50
Number of options vested (in shares)	75,620	108,147
Aggregate intrinsic value, options vested	$ 734	$ 1,690
$ 3
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price (usd per share)	$ 3	$ 3
Number of options outstanding(in shares)	435,767	559,733
Weighted average remaining contractual life	7 years 5 months 26 days	8 years 16 days
Aggregate intrinsic value	$ 4,009	$ 8,469
Weighted average exercise price, options vested (usd per share)	$ 3	$ 3
Number of options vested (in shares)	199,100	192,458
Aggregate intrinsic value, options vested	$ 1,832	$ 2,912
$ 4
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price (usd per share)	$ 4	$ 4
Number of options outstanding(in shares)	64,095	67,975
Weighted average remaining contractual life	8 years 1 month 4 days	9 years 1 month 2 days
Aggregate intrinsic value	$ 526	$ 960
Weighted average exercise price, options vested (usd per share)	$ 4	$ 4
Number of options vested (in shares)	29,361	10,155
Aggregate intrinsic value, options vested	$ 241	$ 143
$ 5
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price (usd per share)	$ 5	$ 5
Number of options outstanding(in shares)	75,417	98,100
Weighted average remaining contractual life	8 years 3 months 4 days	9 years 3 months 4 days
Aggregate intrinsic value	$ 543	$ 1,288
Weighted average exercise price, options vested (usd per share)	$ 5	$ 5
Number of options vested (in shares)	32,260	0
Aggregate intrinsic value, options vested	$ 232	$ 0
$ 7
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price (usd per share)	$ 7	$ 7
Number of options outstanding(in shares)	11,849	53,700
Weighted average remaining contractual life	8 years 4 months 24 days	9 years 4 months 24 days
Aggregate intrinsic value	$ 62	$ 598
Weighted average exercise price, options vested (usd per share)	$ 7	$ 7
Number of options vested (in shares)	4,965	1,001
Aggregate intrinsic value, options vested	$ 26	$ 11
$ 8.50
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price (usd per share)	$ 8.50	$ 8.50
Number of options outstanding(in shares)	1,139,604	1,209,700
Weighted average remaining contractual life	8 years 6 months 6 days	9 years 6 months 4 days
Aggregate intrinsic value	$ 4,217	$ 11,649
Weighted average exercise price, options vested (usd per share)	$ 8.50	$ 8.50
Number of options vested (in shares)	408,500	152,000
Aggregate intrinsic value, options vested	$ 1,511	$ 1,464
$ 9
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price (usd per share)	$ 9	$ 9
Number of options outstanding(in shares)	307,173	325,980
Weighted average remaining contractual life	9 years 1 day	9 years 6 months 26 days
Aggregate intrinsic value	$ 983	$ 2,976
Weighted average exercise price, options vested (usd per share)	$ 9	$ 9
Number of options vested (in shares)	98,226	0
Aggregate intrinsic value, options vested	$ 314	$ 0
$ 11.43
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price (usd per share)	$ 11.43
Number of options outstanding(in shares)	186,533
Weighted average remaining contractual life	9 years 11 months 14 days
Aggregate intrinsic value	$ 142
Weighted average exercise price, options vested (usd per share)	$ 11.43
Number of options vested (in shares)	0
Aggregate intrinsic value, options vested	$ 0
$ 15
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price (usd per share)	$ 15	$ 15
Number of options outstanding(in shares)	50,400	60,800
Weighted average remaining contractual life	8 years 8 months 26 days	9 years 8 months 27 days
Aggregate intrinsic value	$ 0	$ 190
Weighted average exercise price, options vested (usd per share)	$ 15	$ 15
Number of options vested (in shares)	16,241	0
Aggregate intrinsic value, options vested	$ 0	$ 0
$ 18.95
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price (usd per share)	$ 18.95	$ 18.95
Number of options outstanding(in shares)	103,220	124,750
Weighted average remaining contractual life	8 years 11 months 8 days	9 years 11 months 9 days
Aggregate intrinsic value	$ 0	$ 0
Weighted average exercise price, options vested (usd per share)	$ 18.95	$ 18.95
Number of options vested (in shares)	29,989	0
Aggregate intrinsic value, options vested	$ 0	$ 0
$ 19.13
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price (usd per share)	$ 19.13
Number of options outstanding(in shares)	5,000
Weighted average remaining contractual life	9 years 4 months 28 days
Aggregate intrinsic value	$ 0
Weighted average exercise price, options vested (usd per share)	$ 19.13
Number of options vested (in shares)	0
Aggregate intrinsic value, options vested	$ 0
$ 22.18
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price (usd per share)	$ 22.18
Number of options outstanding(in shares)	511,750
Weighted average remaining contractual life	9 years 1 month 12 days
Aggregate intrinsic value	$ 0
Weighted average exercise price, options vested (usd per share)	$ 22.18
Number of options vested (in shares)	0
Aggregate intrinsic value, options vested	$ 0

Stock-based Compensation (Fair

Stock-based Compensation (Fair Value Assumptions) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Jan. 01, 2017	Dec. 27, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected dividend	$ 0	$ 0	$ 0
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Volatility, minimum	37.00%	39.00%	40.00%
Volatility, maximum	39.00%	40.00%	44.00%
Risk-free interest rate, minimum	1.90%	1.10%	1.50%
Risk-free interest rate, maximum	2.30%	2.10%	2.00%
Options and common stock warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Volatility, minimum		37.00%	36.00%
Volatility, maximum		53.00%	48.00%
Risk-free interest rate, minimum		0.60%	0.20%
Risk-free interest rate, maximum		1.70%	2.50%
ESPP shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Volatility, minimum	49.00%
Volatility, maximum	66.00%
Risk-free interest rate, minimum	1.40%
Risk-free interest rate, maximum	1.60%
Minimum | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	6 years	5 years 6 months	5 years 7 months 6 days
Minimum | Options and common stock warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)		1 year 7 months 6 days	3 years 4 months 24 days
Minimum | ESPP shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	6 months
Maximum | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	6 years 1 month 6 days	6 years 7 months 6 days	6 years 6 months
Maximum | Options and common stock warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)		8 years 3 months 18 days	10 years
Maximum | ESPP shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	1 year

Stock-based Compensation (Restr

Stock-based Compensation (Restricted Stock Units) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Jan. 01, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Weighted average fair value (usd per share)	$ 17.72	$ 18.95
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Beginning balance (in shares)	6,950	0
Granted (in shares)	1,276,940	6,950
Vested (in shares)	(125,818)	0
Forfeited or canceled (in shares)	(57,545)	0
Ending balance (in shares)	1,100,527	6,950
Outstanding and expected to vest (in shares)	1,100,527
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Weighted average remaining contractual term	9 years 3 months 6 days	3 years 11 months 6 days
Aggregate intrinsic value, outstanding and expected to vest	$ 13,426	$ 126

Stock-based Compensation (RSU n

Stock-based Compensation (RSU narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Jan. 01, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years
Average recognition period for cost not yet recognized	2 years 9 months 6 days	3 years 2 months 6 days
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unamortized expense	$ 16,272	$ 0
Average recognition period for cost not yet recognized	2 years 8 months 6 days	0 years
Minimum | Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Maximum | Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years

Income Taxes (Schedule of Incom

Income Taxes (Schedule of Income before Income Tax, Domestic and Foreign) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Jan. 01, 2017	Dec. 27, 2015
Income Tax Disclosure [Abstract]
United States	$ 33,451	$ 16,535	$ (7,584)
Foreign	(33,981)	(18,063)	654
Loss before income taxes	$ (530)	$ (1,528)	$ (6,930)

Income Taxes (Schedule of Compo

Income Taxes (Schedule of Components of Income Tax Expense (Benefit)) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Jan. 01, 2017	Dec. 27, 2015
Income Tax Disclosure [Abstract]
Federal	$ (290,000)	$ 266,000	$ 0
State	16,000	1,000	2,000
Foreign	668,000	132,000	113,000
Total current provision for income taxes	394,000	399,000	115,000
Federal	(35,303,000)	0	0
State	(65,000)	0	0
Foreign	32,000	(32,000)	0
Total deferred provision	(35,336,000)	(32,000)	0
Income tax expense (benefit)	$ (34,942,000)	$ 367,000	$ 115,000

Income Taxes (Schedule of Defer

Income Taxes (Schedule of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Jan. 01, 2017
Deferred tax assets:
Accrual, reserve and other	$ 1,471	$ 2,112
Depreciation and amortization	(1,625)	(555)
Net operating loss and credits carry forwards	48,401	59,628
Stock based compensation	1,645	535
Others	64	519
Total gross deferred tax assets	49,956	62,239
Valuation allowance	(14,534)	(62,207)
Total net deferred tax assets	$ 35,422	$ 32

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Jan. 01, 2017	Dec. 27, 2015	Dec. 28, 2014
Operating Loss Carryforwards [Line Items]
Decrease in tax provision, TCJA	$ (16,600,000)
Deferred tax asset, income tax expense	52,500,000
Valuation allowance	14,534,000	$ 62,207,000
Unrecognized tax benefits	5,318,000	5,221,000	$ 4,425,000	$ 3,738,000
Unrecognized tax benefits that would impact effective tax rate	2,800,000
Unrecognized tax benefits, penalties and interest accrued	0
Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	120,200,000	134,100,000
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	104,600,000	104,700,000
Research Tax Credit Carryforward | Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Tax credit carryforward	10,600,000	7,200,000
Research Tax Credit Carryforward | State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Tax credit carryforward	$ 11,000,000	$ 7,700,000

Income Taxes (Schedule of Effec

Income Taxes (Schedule of Effective Income Tax Rate Reconciliation) (Details)	12 Months Ended
	Dec. 31, 2017	Jan. 01, 2017	Dec. 27, 2015
Income Tax Disclosure [Abstract]
US Federal Rate	34.00%	34.00%	34.00%
State income taxes, net of federal benefit	867.10%	0.00%	0.00%
Difference between statutory rate and foreign effective tax rate	(2285.70%)	(437.80%)	1.70%
Other permanent Items	(52.30%)	(125.20%)	(0.80%)
Stock based compensation	1650.10%	(29.20%)	(2.70%)
Research and development credits	610.30%	102.20%	9.50%
Change in valuation allowance	8988.60%	477.60%	(43.40%)
Foreign Income	(96.10%)	(75.80%)	0.00%
Foreign Tax Credit	0.00%	30.70%	0.00%
Federal Rate Change	(31.281)	0	0
Effective Income Tax Rate Reconciliation, Percent	6587.90%	(23.50%)	(1.70%)

Income Taxes (Unrecognized Tax

Income Taxes (Unrecognized Tax Benefits) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Jan. 01, 2017	Dec. 27, 2015
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	$ 5,221	$ 4,425	$ 3,738
Increases related to current year’s unrecognized tax benefits	1,569	888	687
Increases related to prior year’s unrecognized tax benefits	68	0	0
Decreases related to prior year’s unrecognized tax benefits	(1,540)	(92)	0
Ending balance	$ 5,318	$ 5,221	$ 4,425

Employee Benefit Plans (Details

Employee Benefit Plans (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)
Retirement Benefits [Abstract]
Contribution amount by Company	$ 0.5

Segment Information and Opera71

Segment Information and Operations by Geographic Area (Narrative) (Details)	12 Months Ended
	Dec. 31, 2017segment
Segment Reporting [Abstract]
Number of operating segments	1

Segment Information and Opera72

Segment Information and Operations by Geographic Area (Schedule of Revenue by Geographical Area) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Jan. 01, 2017	Dec. 27, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 176,359	$ 129,069	$ 83,773
Geographic Concentration Risk
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 176,359	$ 129,069	$ 83,773
Percentage of revenue	100.00%	100.00%	100.00%
Geographic Concentration Risk | China
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 119,821	$ 86,107	$ 45,102
Percentage of revenue	68.00%	66.00%	54.00%
Geographic Concentration Risk | Taiwan
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 17,780	$ 13,752	$ 10,169
Percentage of revenue	10.00%	11.00%	12.00%
Geographic Concentration Risk | Tunisia
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 13,410	$ 13,755	$ 5,414
Percentage of revenue	8.00%	11.00%	6.00%
Geographic Concentration Risk | United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 283	$ 291	$ 3,326
Percentage of revenue	0.00%	0.00%	4.00%
Geographic Concentration Risk | Other foreign countries
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 25,065	$ 15,164	$ 19,762
Percentage of revenue	14.00%	12.00%	24.00%

Related Party transactions (Nar

Related Party transactions (Narrative) (Details) - USD ($) $ in Thousands	Sep. 29, 2017	Dec. 31, 2017	Jan. 01, 2017	Dec. 27, 2015
Related Party Transaction [Line Items]
Intangible asset		$ 2,987
Lip-Bu Tan
Related Party Transaction [Line Items]
Purchases from related party		$ 3,000	$ 1,700	$ 1,200
Software License Arrangement
Related Party Transaction [Line Items]
Amortization of intangible assets	$ 300

Related Party transactions (Det

Related Party transactions (Details) - Investor - Agreement with RUSNANO $ in Millions	Dec. 31, 2014period	Jul. 31, 2014USD ($)period
Related Party Transaction [Line Items]
Contractual obligation		$ 13
Annual periods | period	6	6
Contractual obligation, year 1		$ 2.2
Contractual obligation, year 2		1.7
Contractual obligation, year 3		2
Contractual obligation, year 4		2.2
Contractual obligation, year 5		2.4
Contractual obligation, year 6		$ 2.5
Funding obligation penalty		10.00%
Difference between the funding obligation and the actual funding		80.00%