Aquantia 10-Q 9 May 19 2019 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2019	May 03, 2019
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Trading Symbol	AQ
Entity Registrant Name	AQUANTIA CORP
Entity Central Index Key	0001316016
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Small Business	false
Entity Common Stock, Shares Outstanding		35,532,571

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 8,480	$ 6,684
Short-term investments	53,895	60,730
Accounts receivable	10,350	16,927
Inventories	17,015	14,474
Prepaid expenses and other current assets	1,801	2,018
Total current assets	91,541	100,833
Property and equipment, net	11,211	9,225
Operating lease assets, net	5,644
Intangible assets, net	3,546	3,748
Other assets	616	617
Total assets	112,558	114,423
Current liabilities:
Accounts payable	6,349	5,495
Accrued liabilities	15,750	13,907
Operating lease liabilities - short term	839
Total current liabilities	22,938	19,402
Operating lease liabilities - long term	6,251
Other long-term liabilities	413	1,799
Total liabilities	29,602	21,201
Commitments and contingencies (Note 3 and Note 6)
Stockholders’ equity:
Additional paid-in capital	303,473	300,791
Accumulated other comprehensive loss	(4)	(123)
Accumulated deficit	(220,513)	(207,446)
Total stockholders’ equity	82,956	93,222
Total liabilities and stockholders’ equity	$ 112,558	$ 114,423

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Mar. 31, 2019	Dec. 31, 2018
Statement Of Financial Position [Abstract]
Common stock, par value	$ 0.00001	$ 0.00001
Common stock, shares authorized	95,000,000	95,000,000
Common stock, shares outstanding	35,508,553	35,050,425

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Statement [Abstract]
Revenue	$ 17,022	$ 28,358
Cost of revenue	8,056	12,241
Gross profit	8,966	16,117
Operating expenses:
Research and development	16,070	12,574
Sales and marketing	2,719	2,287
General and administrative	3,422	2,997
Total operating expenses	22,211	17,858
Loss from operations	(13,245)	(1,741)
Other income (expense):
Other income, net	368	248
Total other income (expense)	368	248
Loss before income tax expense	(12,877)	(1,493)
Provision for (benefit from) income taxes	190	(125)
Net loss	$ (13,067)	$ (1,368)
Net loss per share, basic and diluted	$ (0.37)	$ (0.04)
Weighted-average shares used to compute net loss per share, basic and diluted	35,158	33,495
Comprehensive income:
Net loss	$ (13,067)	$ (1,368)
Other comprehensive income (loss), net of tax:
Unrealized gains (losses) - short-term investments	119	(131)
Comprehensive loss	$ (12,948)	$ (1,499)

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENT OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive loss	Accumulated Deficit
Cumulative effect upon adoption of ASC 606	$ 35				$ 35
BALANCE at Dec. 31, 2017	90,914		$ 288,719	$ (96)	(197,709)
BALANCE, Shares at Dec. 31, 2017		33,523,683
Other comprehensive loss (gain) - unrealized loss (gain) on short-term investments	(131)			(131)
Exercise of stock options, shares		3,466
Issuance of restricted stock units		102,500
Issuance of restricted stock units (reversed, not yet issued)		(137,529)
Issuance of common stock, netupon exercise of warrants		48,305
Repurchase of stock options, shares		(3,626)
IPO Costs	22		22
Stock-based compensation expense	978		978
Net loss	(1,368)				(1,368)
BALANCE at Mar. 31, 2018	90,406		289,675	(227)	(199,042)
BALANCE, Shares at Mar. 31, 2018		33,536,799
IPO Costs	(22)		(22)
BALANCE at Dec. 31, 2018	$ 93,222		300,791	(123)	(207,446)
BALANCE, Shares at Dec. 31, 2018	35,050,425	35,050,425
Other comprehensive loss (gain) - unrealized loss (gain) on short-term investments	$ 119			119
Exercise of stock options	392		392
Exercise of stock options, shares		132,692
Issuance of restricted stock units		325,436
Stock-based compensation expense	2,290		2,290
Net loss	(13,067)				(13,067)
BALANCE at Mar. 31, 2019	$ 82,956		$ 303,473	$ (4)	$ (220,513)
BALANCE, Shares at Mar. 31, 2019	35,508,553	35,508,553

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities
Net loss	$ (13,067)	$ (1,368)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	1,616	1,385
Stock-based compensation expense	2,290	978
Accretion of investment premium, net of amortization of discount	(112)
Changes in operating assets and liabilities:
Accounts receivable	6,577	4,595
Inventories	(2,541)	2,313
Operating lease assets, net	254
Prepaid expenses and other assets	218	1,953
Accounts payable	(1,870)	(1,193)
Accrued and other liabilities	1,873	(860)
Operating lease liabilities	(224)
Net cash provided by (used in) operating activities	(4,986)	7,803
Cash flows from investing activities
Purchases of property and equipment	(676)	(731)
Proceeds from sales of short-term investments	1,000
Proceeds from maturities of short-term investments	14,000	5,400
Purchases of short-term investments	(7,934)	(15,604)
Net cash provided by (used in) investing activities	6,390	(10,935)
Cash flows from financing activities
Proceeds from exercise of stock options	392
Purchases of IP licenses		(26)
Payment of costs related to initial public offering		(276)
Net cash provided by (used in) financing activities	392	(302)
Net decrease in cash and cash equivalents	1,796	(3,434)
Cash and cash equivalents at beginning of period	6,684	8,040
Cash and cash equivalents at end of period	8,480	4,606
Supplemental disclosures of cash flow information
Cash paid for interest	10
Cash paid for income taxes	125
Cash paid for amounts included in the lease liabilities	418
Cashless exercises of warrants, net of assumed proceeds from shares		550
Property and equipment received and accrued	$ 2,810	$ 345

Organization, Description of Bu

Organization, Description of Business and Basis for Presentation	3 Months Ended
	Mar. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Organization, Description of Business and Basis for Presentation	1. Organization, Description of Business and Basis for Presentation Organization —Aquantia Corp. (together with its subsidiaries, the “Company”) was incorporated in Delaware on January 27, 2004. The Company is a leader in the design, development and marketing of advanced high-speed communications integrated circuits, or ICs, for Ethernet connectivity in the data center, enterprise infrastructure, access and automotive markets. Basis of Presentation and Principles of Consolidation — The accompanying unaudited condensed consolidated financial statements included herein have been prepared by us in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”), for interim financial information and the rules and regulations of the Securities and Exchange Commission (“SEC”). In the opinion of management, normal recurring adjustments considered necessary for a fair presentation have been reflected in these condensed consolidated financial statements. Certain information and note disclosures normally included in the financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to such rules and regulations. The condensed consolidated balance sheet as of December 31, 2018 has been derived from the audited financial statements for the fiscal year then ended included in the Company’s Annual Report on Form 10-K filed with the SEC on March 6, 2019 (the “2018 Annual Report on Form 10-K”), but does not include all of the information and notes required by U.S. GAAP for complete consolidated financial statements. The financial information included in this Quarterly Report on Form 10-Q should be read in conjunction with the audited consolidated financial statements as of and for the fiscal year ended December 31, 2018 and the related notes thereto included in the 2018 Annual Report on Form 10-K.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies During the three months ended March 31, 2019, there have been no changes in our significant accounting policies as described in the Company’s 2018 Annual Report on Form 10-K, except as discussed below: Recent Accounting Pronouncements — Adopted In August 2018, the Financial Accounting Standards Board (“FASB”) issued ASU 2018-15, Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract. In February 2018, the FASB released ASU 2018-2, “ Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income. In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842)

Balance Sheet Components

Balance Sheet Components	3 Months Ended
	Mar. 31, 2019
Balance Sheets Components [Abstract]
Balance Sheet Components	3. Balance Sheet Components Inventories consisted of the following (in thousands): As of March 31, As of December 31, 2019 2018 Processed wafers $ 1,277 $ 1,233 Work in process 7,445 5,990 Finished goods 8,293 7,251 Total inventories $ 17,015 $ 14,474 Property and equipment, net consisted of the following (in thousands): As of March 31, As of December 31, Estimated Useful Lives 2019 2018 Machinery and equipment 2-3 years $ 15,925 $ 15,237 Production masks 4 years 8,101 5,401 Software and computer equipment 3 years 4,459 4,492 Leasehold improvements Shorter of estimated life of asset or remaining lease term 1,414 1,414 Office furniture and fixtures 3 years 163 117 Total property and equipment 30,062 26,661 Less: accumulated depreciation and amortization (18,851 ) (17,436 ) Property and equipment, net $ 11,211 $ 9,225 Depreciation and amortization of property and equipment totaled $1.4 million and $1.2 million for the three months ended March 31, 2019 and 2018, respectively. Intangible assets, net were carried at cost, less accumulated amortization. Intangible assets were as follows (in thousands): As of March 31, As of December 31, Estimated Useful Lives 2019 2018 IP license 7 years $ 5,416 $ 5,416 Patents 10-12 years 348 348 Total intangible assets 5,764 5,764 Less: accumulated amortization (2,218 ) (2,016 ) Intangible assets, net $ 3,546 $ 3,748 Amortization of intangible assets totaled $0.2 million and $0.2 million for the three months ended March 31, 2019 and 2018, respectively. Amortization expense related to amortizable intangibles in future periods as of March 31, 2019 is expected to be as follows (in thousands): 2019 (remaining) $ 606 2020 808 2021 808 2022 800 2023 and thereafter 524 Total $ 3,546 Operating lease asset and liabilities The Company has entered into operating leases primarily for real estate. As of adoption these leases have terms which range from 1 year to 6 years, and often include one or more options to renew. These renewal terms can extend the lease term from 1 to 9 years, and are included in the lease term when it is reasonably certain that the Company will exercise the option. After the adoption of ASC 842 on January 1, 2019, an asset has been included on the Company’s condensed consolidated balance sheet as “operating lease assets, net” which represents the Company’s right to use the underlying asset for the lease term. Similarly, the Company has recorded its obligation to make lease payments within its condensed consolidated balance sheet as “operating lease liabilities” and classified these liabilities as short-term (“operating lease liabilities – short term”) and long-term (“operating lease liabilities – long term”) based on the timing and amounts of payment. The Company determines whether an arrangement is a lease at inception. Some lease agreements contain the lease and non-lease components, which are accounted for a single lease component. Operating lease right-of-use assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. As of March 31, 2019, total right-of-use assets and operating lease liabilities were approximately $5.6 million and $7.1 million, respectively and presented within the condensed consolidated balance sheet as noted above. The Company has entered into various short-term operating leases, primarily for office equipment, automotive, and other facilities, with an initial term of twelve months or less. Leases with a lease term of twelve months or less have not been recorded on the Company’s condensed consolidated balance sheet. No new leases were entered into during the quarter ended March 31, 2019. All operating lease expense is recognized on a straight-line basis over the lease term. In the three months ended March 31, 2019, the Company recognized approximately $0.5 million in total lease costs. Because the rate implicit in each lease is not readily determinable, the Company used the estimated interest rate for collateralized loan over a similar term to determine the present value of the lease payments. The weighted-average remaining lease term was 3.3 years and the weighted-average discount rate used was 8.5%. Maturities of lease liabilities as of March 31, 2019 were as follows (in thousands): 2019 (remaining) $ 1,020 2020 1,513 2021 2,018 2022 2,059 2023 1,793 2024 and thereafter 431 Total 8,834 Less imputed interest (1,744 ) Total lease liabilities $ 7,090 Refer to Note 6 for the future minimum operating lease payments under ASC 840. Accrued liabilities consisted of the following (in thousands): As of March 31, As of December 31, 2019 2018 Accrued compensation and related benefits $ 4,759 $ 5,301 Customer Deposit - 40 Accrued IP License 5,266 4,829 Accrued technical consulting and professional services 237 412 Accrued royalty, rebates and commission 583 443 Other accrued liabilities 4,905 2,882 Total accrued liabilities $ 15,750 $ 13,907

Financial Instruments

Financial Instruments	3 Months Ended
	Mar. 31, 2019
Investments All Other Investments [Abstract]
Financial Instruments	4. Financial Instruments The following is a summary of financial instruments (in thousands): As of March 31, 2019 Gross Gross Unrealized Unrealized Estimated Fair Cost Gains Losses Values Available-for sale securities Commercial paper $ 10,939 $ — $ (1 ) $ 10,938 Money market funds 736 — — 736 Corporate bonds 45,971 — (4 ) 45,967 U.S. government securities 1,980 2 — 1,982 Total available-for-sale securities $ 59,626 $ 2 $ (5 ) $ 59,623 Reported in: Cash and cash equivalents $ 5,728 Short-term investments 53,895 Total available-for-sale securities $ 59,623 As of December 31, 2018 Gross Gross Unrealized Unrealized Estimated Fair Cost Gains Losses Values Available-for sale securities Commercial paper $ 10,173 $ — $ (9 ) $ 10,164 Money market funds 403 — — 403 Corporate bonds 52,448 — (114 ) 52,334 U.S. government securities 1,972 — - 1,972 Total available-for-sale securities $ 64,996 $ — $ (123 ) $ 64,873 Reported in: Cash and cash equivalents $ 4,143 Short-term investments 60,730 Total available-for-sale securities $ 64,873 The contractual maturities of available-for-sale securities are presented in the following table (in thousands): As of March 31, 2019 Amortized Cost Basis Estimated Fair Value Due in one year or less $ 59,626 $ 59,623 Due between one and five years — — $ 59,626 $ 59,623 Gross realized gains and gross realized losses on sales of available-for-sale securities for the three months ended March 31, 2019 were not significant.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	5. Fair Value Measurements The Company defines fair value as the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. When determining the fair value measurements for assets and liabilities which are required to be recorded at fair value, the Company considers the principal or most advantageous market in which to transact and the market-based risk. The Company applies fair value accounting for all financial assets and liabilities that are recognized or disclosed at fair value in the financial statements on a recurring basis. The Company categorizes assets and liabilities recorded at fair value based upon the level of judgment associated with inputs used to measure their fair value. The categories are as follows: Level 1 —Observable inputs, such as quoted prices in active markets for identical, unrestricted assets, or liabilities. Level 2 —Quoted prices for similar assets or liabilities, or inputs other than quoted prices in active markets that are observable either directly or indirectly. Level 3 —Unobservable inputs in which there is little or no market data, which require the Company to develop its own assumptions about the assumptions market participants would use in pricing the asset or liability. Valuation techniques include use of option-pricing models, discounted cash flows models, and similar techniques. The hierarchy requires the Company to use observable market data, when available, and to minimize the use of unobservable inputs when determining fair value. The following tables represent the Company’s financial assets measured at fair value on a recurring basis categorized by the fair value hierarchy as of March 31, 2019 and December 31, 2018 (in thousands): As of March 31, 2019 Level 1 Level 2 Level 3 Total Financial asset— available-for-sales securities Money market funds $ 736 $ — $ — $ 736 Commercial paper — 10,938 — 10,938 Corporate bonds — 45,967 — 45,967 U.S. government securities — 1,982 — 1,982 Total financial asset—available-for-sales securities $ 736 $ 58,887 $ — $ 59,623 As of December 31, 2018 Level 1 Level 2 Level 3 Total Financial asset— available-for-sales securities Money market funds $ 403 $ — $ — $ 403 Commercial paper — 10,164 — 10,164 Corporate bonds — 52,334 — 52,334 U.S. government securities — 1,972 — 1,972 Total financial asset—available-for-sales securities $ 403 $ 64,470 $ — $ 64,873 There were no transfers within the hierarchy during the three months ended March 31, 2019 and 2018.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	6. Commitments and Contingencies Lease and purchase obligations— The Company leases office and research facilities under operating leases for its U.S. headquarters and international locations that expire at various dates through March 2024. Under any lease agreement that contains escalating rent provisions, lease expense is recorded on a straight-line basis over the lease term. In addition, the Company has purchase obligations which included agreements and issued purchase orders containing non-cancelable payment terms to purchase goods and services. As previously disclosed in our Annual Report on Form 10-K for the year ended December 31, 2018 and under the previous lease accounting standard ASC 840, the aggregate future non-cancelable minimum rental payments on our operating leases, as of December 31, 2018, were as follows (in thousands): Total Operating Purchase Lease and Purchase Leases Obligations Obligations 2019 $ 1,482 $ 15,674 $ 17,156 2020 1,516 4,247 5,763 2021 1,993 1,008 3,001 2022 2,033 — 2,033 2023 and thereafter 2,217 — 2,217 Total $ 9,241 $ 20,929 $ 30,170 Litigation— The Company accrues for contingencies when it believes that a loss is probable and that it can reasonably estimate the amount of any such loss and the Company has made an assessment of the probability of incurring any such losses and whether or not those losses are estimable. Although the Company is not currently subject to any litigation, and the Company is not aware of any litigation currently threatened against it, the Company may be subject to legal proceedings, claims and litigation, including intellectual property litigation, arising in the ordinary course of business. Such matters are subject to many uncertainties and outcomes and are not predictable with assurance. The Company accrues amounts that it believes are adequate to address any liabilities related to legal proceedings and other loss contingencies that it believes will result in a probable loss that is reasonably estimable. To the extent there is a reasonable possibility that a loss exceeding amounts already recognized may be incurred and the amount of such additional loss would be material, the Company will either disclose the estimated additional loss or state that such an estimate cannot be made. The Company does not currently believe that it is reasonably possible that losses in connection with litigation arising in the ordinary course of business would be material. Indemnification— Under the indemnification provisions of the Company’s standard sales-related contracts, the Company agrees to defend its customers against third-party claims asserting infringement of certain intellectual property rights, which may include patents, copyrights, trademarks, or trade secrets, and to pay judgments entered on such claims. Certain agreements include indemnification provisions that could potentially expose the Company to losses in excess of the amount received under the agreement. In addition, the Company indemnifies its directors and certain of its officers while they are serving in good faith in such capacities. To date, the Company has not incurred costs to defend lawsuits or settle claims related to these indemnification agreements.

Common Stock and Share-based Co

Common Stock and Share-based Compensation	3 Months Ended
	Mar. 31, 2019
Equity [Abstract]
Common Stock and Share-based Compensation	7 . Common Stock and Share-based Compensation The Company’s certificate of incorporation, as of March 31, 2019 and December 31, 2018, authorized the Company to issue up to 95,000,000 shares of common stock and 5,000,000 shares of preferred stock, each at $0.00001 par value per share. As of March 31, 2019, no preferred stock was outstanding. Each share of common stock is entitled to one vote. The holders of common stock are also entitled to receive dividends out of funds legally available. No dividends have been declared to date. 2015 Equity Incentive Plan and 2004 Equity Incentive Plan Under the Company’s 2015 Equity Incentive Plan and 2004 Equity Incentive Plan, shares of common stock were reserved for the issuance of incentive stock options (“ISO”); nonstatutory stock options (“NSO”); or the sales of restricted common stock to employees, officers, directors, and consultants of the Company. The exercise price of an option is determined by the board of directors when the option is granted and may not be less than 85% of the fair market value of the shares on the date of grant, provided that the exercise price of an ISO is not less than 100% of the fair market value of the shares on the date of grant and the exercise price of any option granted to a 10% stockholder is not less than 110% of the fair market value of the shares on the date of grant. ISOs granted under the Plan generally vest 25% after the completion of 12 months of service and the balance in equal monthly installments over the next 36 months of service and expire 10 years from the grant date. NSOs vest as per the specific agreement and expire 10 years from the date of grant. The Plan allows for early exercise of options prior to full vesting as determined by the board of directors and set forth in the stock option agreements governing such options. Exercises of unvested options are subject to repurchase by the Company at not less than the original exercise price upon termination of employment. 2017 Equity Incentive Plan In November 2017, the Company adopted the 2017 Equity Incentive Plan, or 2017 Plan, and all shares reserved for grant under the 2015 Equity Incentive Plan and 2004 Equity Incentive Plan were cancelled. The 2017 Plan had 5,047,440 common shares reserved, plus any shares subject to outstanding stock options or other stock awards that were granted under the 2015 Equity Incentive Plan and 2004 Equity Incentive Plan that were forfeited, terminate, expire or are otherwise not issued. In addition, the shares reserved under the 2017 Plan will automatically increase on the first day of each calendar year until January 1, 2027, by an amount equal to 5% of the total number of shares of the Company’s capital stock outstanding on the last day of the calendar month before the date of the automatic increase, or a lesser number of shares determined by the board of Stock Options Activity under the Company’s stock option plan is set forth below: Weighted- Weighted Average Average Remaining Aggregate Exercise Contractual Intrinsic Value Number of Shares Price Term (Years) (in thousands) Balance—December 31, 2018 2,297,403 $ 4.49 6.9 $ 9,858 Granted — $ — Exercised (132,692 ) $ 2.95 Canceled (7,981 ) $ 6.26 Balance—March 31, 2019 2,156,730 $ 4.58 6.8 $ 9,683 Vested and exercisable—March 31, 2019 1,524,974 $ 3.93 6.4 $ 7,842 Vested and exercisable—December 31, 2018 1,547,754 $ 3.74 6.5 $ 7,803 As of March 31, 2019, approximately $1.7 million of unrecognized stock compensation costs related to awards were expected to be recognized over a weighted-average period of 2.8 years. As of December 31, 2018, approximately $2.0 million of unrecognized stock compensation costs related to awards were expected to be recognized over a weighted-average period of 2.8 years. The aggregate intrinsic value of options exercised during the three months ended March 31, 2019 was $0.7 million. The aggregate intrinsic value of options exercised during the year ended December 31, 2018 was $7.1 million. There were no options granted during the three months ended March 31, 2019 and 2018. The weighted-average grant-date fair value of options granted during the year ended December 31, 2018 was $5.46 per share. Restricted Stock Unit Awards The Company grants restricted stock units (RSU) to employees under the 2017 Plan. RSUs granted typically vest ratably over a 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, reduced by the discounted present value of dividends expected to be declared before the awards vest. Compensation expense is recognized on a straight-line basis over the requisite service period of each grant. Each RSU award granted from the 2017 Plan will reduce the number of shares available for issuance under the 2017 Plan by one share. For the three months ended March 31, 2019, unamortized compensation expense related to RSU was approximately $19.6 million, to be recognized over 3.1 years. For the year ended December 31, 2018, unamortized compensation expense related to RSU was approximately $15.8 million, to be recognized over 3.0 years. Activity under the Company’s RSU is set forth below : Weighted Average Market Number of Shares Value Balance—December 31, 2018 1,554,089 $ 12.73 Granted 670,941 $ 8.51 Released (325,436 ) $ 12.76 Canceled (14,010 ) $ 12.22 Balance—March 31, 2019 1,885,584 $ 11.02 Employee Stock Purchase Plan Concurrent with the completion of the Company’s initial public offering (“IPO”) in November 2017, the Company adopted the 2017 Employee Stock Purchase Plan, or ESPP. The ESPP authorizes the issuance of 2,018,975 shares of common stock outstanding under purchase rights granted to its employees. In addition, the shares reserved under the ESPP Plan will automatically increase on the first day of each calendar year until January 1, 2027, by the lesser of (i) an amount equal to 2% of the total number of shares of the Company’s capital stock outstanding on the last day of the calendar month before the date of the automatic increase, (ii) 1,000,000 shares of common stock, and (iii) a lesser number of shares determined by the board of directors prior to the date of such automatic increase. The ESPP allows eligible employees to purchase shares of the Company’s common stock at a discount through payroll deductions of up to 15% of their eligible compensation, subject to any plan limitations. The ESPP generally provides for offering periods and 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. 366,369 shares were issued as of December 31, 2018 under the ESPP. Shares expected to be issued under the ESPP were 191,446 for the offering period outstanding as of March 31, 2019. The calculated fair value of the shares under the ESPP for the period started on November 16, 2018 was estimated using the Black-Scholes model with the following assumptions: risk-free interest rate of 2.36%, expected term of 0.5 year, expected dividends of 0% and volatility of 22%. For the three months ended March 31, 2019, unamortized compensation expense related to ESPP was approximately $0.2 million, to be recognized over approximately two months. For the year ended December 31, 2018, unamortized compensation expense related to ESPP was approximately $0.5 million, to be recognized over approximately five months. The Company uses the straight-line vesting attribution method to record stock-based compensation expense. Stock-based compensation expense recognized in the consolidated statements of operations and comprehensive loss for options, restricted stock units and ESPP was as follows (in thousands): Three Months Ended March 31, 2019 2018 Cost of revenue $ 66 $ 25 Research and development 1,232 573 Sales and marketing 350 111 General and administrative 642 269 Total $ 2,290 $ 978 No income tax benefit associated with stock-based compensation expense was recognized in the condensed consolidated statements of operations and comprehensive loss for the three months ended March 31, 2019 and 2018.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	8. Income Taxes The Company recorded an income tax provision of $0.2 million and benefit of $0.1 million for the three months ended March 31, 2019 and 2018, respectively. The income tax benefit for the three months ended March 31, 2018 consisted primarily of a credit to foreign jurisdiction. Although the Company files U.S. federal and various state tax returns, the Company’s only major tax jurisdictions are the United States and California. As a result of NOL carryforwards, all of the Company’s tax years are open to federal and state examination in the United States. All tax years are open to examination in various foreign countries.

Net Loss Per Share

Net Loss Per Share	3 Months Ended
	Mar. 31, 2019
Earnings Per Share [Abstract]
Net Loss Per Share	9. Net Loss Per Share The following table summarizes the computation of basic and diluted net loss per share (in thousands, except per share data): Three Month Ended March 31, 2019 2018 Net loss $ (13,067 ) $ (1,368 ) Weighted-average common shares outstanding 35,158,470 33,494,807 Less: Shares subject to repurchase — — Weighted-average shares outstanding 35,158,470 33,494,807 Net loss per share, basic and diluted $ (0.37 ) $ (0.04 ) Basic net loss per share is computed by dividing the net loss by the weighted-average number of common shares outstanding for the period. The following potentially dilutive securities outstanding have been excluded from the computation of diluted weighted-average shares outstanding because such securities have an antidilutive impact due to losses reported (in common stock equivalent shares): As of As of March 31, December 31, 2019 2018 Stock options to purchase common stock 2,156,730 2,297,403 Unvested restricted stock units 1,885,584 1,554,089 Common stock warrants 83,695 83,695 Total 4,126,009 3,935,187

Segment Reporting

Segment Reporting	3 Months Ended
	Mar. 31, 2019
Segment Reporting [Abstract]
Segment Reporting	10. Segment Reporting The Company operates in one reportable segment related to the design, development and sale of network communication integrated circuits. The Company’s chief operating decision-maker (“CODM”) is its Chief Executive Officer, who reviews operating results on an aggregate basis and manages the Company’s operations as a whole for the purpose of evaluating financial performance and allocating resources. Substantially all of the Company’s long-lived assets were attributable to operations in the United States as of March 31, 2019 and December 31, 2018. The following table summarizes revenue by market (in thousands): Three Months Ended March 31, 2019 2018 Revenue by market: Data Center $ 8,211 $ 16,269 Enterprise Infrastructure 5,471 9,511 Access 3,206 2,531 Automotive 134 47 Total revenue $ 17,022 $ 28,358 The Company sells its products worldwide and attributes revenue to the geography where the product is shipped. The geographical distribution of revenue as a percentage of total revenue for the periods indicated was as follows: Three Months Ended March 31, 2019 2018 Malaysia 42 % 62 % China 32 22 United States 8 1 Other 18 15 Total 100 % 100 %

Concentrations

Concentrations	3 Months Ended
	Mar. 31, 2019
Risks And Uncertainties [Abstract]
Concentrations	11. Concentrations Credit —Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash and cash equivalents and accounts receivable. The Company’s cash equivalents consist of cash and money market accounts with a financial institution that management believes to be of high-credit quality; however, at times, balances exceed federally insured limits. Amounts held on deposit at financial institutions in excess of Federal Deposit Insurance Corporation-insured amounts were $0.6 million and $1.1 million as of March 31, 2019 and December 31, 2018, respectively. Significant Customers —Credit risk with respect to accounts receivable is concentrated with two large customers that contribute a majority of the Company’s business and is mitigated by a relatively short collection period. Collateral is not required for accounts receivable. The fair value of accounts receivable approximates their carrying value. Revenue and accounts receivable concentrated with significant customers and their manufacturing subcontractors as a percentage of accounts receivable and total revenue were as follows: As of As of March 31, December 31, 2019 2018 Accounts Receivable: Customer A 34 % 42 % Customer B 8 19 Three Months Ended March 31, 2019 2018 Revenue: Customer A 40 % 55 % Customer B 16 28 Significant Suppliers — The Company depends on a limited number of subcontractors and suppliers for its wafer and substrate supply and to fabricate, assemble, and test its semiconductor devices. The Company generally sources its production through standard purchase orders and has wafer supply and assembly and test agreements with certain outside contractors. While the Company seeks to maintain a sufficient level of supply and endeavors to maintain ongoing communications with suppliers to guard against interruptions or cessation of supply, business and results of operations could be adversely affected by a stoppage or delay of supply, substitution of more expensive or less reliable products or services, receipt of defective semiconductor devices, an increase in the price of products, or an inability to obtain reduced pricing from suppliers in response to competitive pressures.

Employee Benefit Plan

Employee Benefit Plan	3 Months Ended
	Mar. 31, 2019
Text Block [Abstract]
Employee Benefit Plan	12. Employee Benefit Plan The Company has established a 401(k) plan, which permits participants to make contributions by salary deduction pursuant to Section 401(k) of the Internal Revenue Code. The Company may, at its discretion, make matching contributions to the 401(k) Plan. The Company has made no contributions to the 401(k) Plan since its inception.

Subsequent Event

Subsequent Event	3 Months Ended
	Mar. 31, 2019
Subsequent Events [Abstract]
Subsequent Event	13. Subsequent Event On May 6, 2019, the Company and Marvell Technology Group Ltd., a Bermuda exempted company (“Marvell”), entered into an Agreement and Plan of Merger (the “Merger Agreement”) by and among the Company, Marvell and Aquantia Acquisition Corp., a Delaware corporation and a wholly owned subsidiary of Marvell (“Merger Sub”) providing for the merger of Merger Sub with and into the Company (the “Merger”) with the Company surviving the Merger as a wholly owned subsidiary of Marvell. Under the terms of the definitive agreement, Marvell will acquire all outstanding shares of the Company’s common stock in exchange for consideration of $13.25 per share in cash. The Merger Agreement contains representations and warranties customary for transactions of this type. The completion of the Merger is subject to the satisfaction or waiver of a number of closing conditions. The Merger Agreement provides Marvell and the Company with certain termination rights and, under certain circumstances, may require Marvell or the Company to pay a termination fee.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements — Adopted In August 2018, the Financial Accounting Standards Board (“FASB”) issued ASU 2018-15, Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract. In February 2018, the FASB released ASU 2018-2, “ Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income. In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842)

Balance Sheet Components (Table

Balance Sheet Components (Tables)	3 Months Ended
	Mar. 31, 2019
Balance Sheets Components [Abstract]
Schedule of Inventories	Inventories consisted of the following (in thousands): As of March 31, As of December 31, 2019 2018 Processed wafers $ 1,277 $ 1,233 Work in process 7,445 5,990 Finished goods 8,293 7,251 Total inventories $ 17,015 $ 14,474
Schedule of Property and Equipment, Net	Property and equipment, net consisted of the following (in thousands): As of March 31, As of December 31, Estimated Useful Lives 2019 2018 Machinery and equipment 2-3 years $ 15,925 $ 15,237 Production masks 4 years 8,101 5,401 Software and computer equipment 3 years 4,459 4,492 Leasehold improvements Shorter of estimated life of asset or remaining lease term 1,414 1,414 Office furniture and fixtures 3 years 163 117 Total property and equipment 30,062 26,661 Less: accumulated depreciation and amortization (18,851 ) (17,436 ) Property and equipment, net $ 11,211 $ 9,225
Schedule of Intangible Assets	Intangible assets, net were carried at cost, less accumulated amortization. Intangible assets were as follows (in thousands): As of March 31, As of December 31, Estimated Useful Lives 2019 2018 IP license 7 years $ 5,416 $ 5,416 Patents 10-12 years 348 348 Total intangible assets 5,764 5,764 Less: accumulated amortization (2,218 ) (2,016 ) Intangible assets, net $ 3,546 $ 3,748
Schedule of Amortization Expense Related to Amortizable Intangibles In Future Periods	Amortization expense related to amortizable intangibles in future periods as of March 31, 2019 is expected to be as follows (in thousands): 2019 (remaining) $ 606 2020 808 2021 808 2022 800 2023 and thereafter 524 Total $ 3,546
Schedule of Maturities of Lease Liabilities	Maturities of lease liabilities as of March 31, 2019 were as follows (in thousands): 2019 (remaining) $ 1,020 2020 1,513 2021 2,018 2022 2,059 2023 1,793 2024 and thereafter 431 Total 8,834 Less imputed interest (1,744 ) Total lease liabilities $ 7,090
Schedule of Accrued Liabilities	Accrued liabilities consisted of the following (in thousands): As of March 31, As of December 31, 2019 2018 Accrued compensation and related benefits $ 4,759 $ 5,301 Customer Deposit - 40 Accrued IP License 5,266 4,829 Accrued technical consulting and professional services 237 412 Accrued royalty, rebates and commission 583 443 Other accrued liabilities 4,905 2,882 Total accrued liabilities $ 15,750 $ 13,907

Financial Instruments (Tables)

Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2019
Investments All Other Investments [Abstract]
Summary of Financial Instruments	The following is a summary of financial instruments (in thousands): As of March 31, 2019 Gross Gross Unrealized Unrealized Estimated Fair Cost Gains Losses Values Available-for sale securities Commercial paper $ 10,939 $ — $ (1 ) $ 10,938 Money market funds 736 — — 736 Corporate bonds 45,971 — (4 ) 45,967 U.S. government securities 1,980 2 — 1,982 Total available-for-sale securities $ 59,626 $ 2 $ (5 ) $ 59,623 Reported in: Cash and cash equivalents $ 5,728 Short-term investments 53,895 Total available-for-sale securities $ 59,623 As of December 31, 2018 Gross Gross Unrealized Unrealized Estimated Fair Cost Gains Losses Values Available-for sale securities Commercial paper $ 10,173 $ — $ (9 ) $ 10,164 Money market funds 403 — — 403 Corporate bonds 52,448 — (114 ) 52,334 U.S. government securities 1,972 — - 1,972 Total available-for-sale securities $ 64,996 $ — $ (123 ) $ 64,873 Reported in: Cash and cash equivalents $ 4,143 Short-term investments 60,730 Total available-for-sale securities $ 64,873
Summary of Contractual Maturities of Available-for-sale Securities	The contractual maturities of available-for-sale securities are presented in the following table (in thousands): As of March 31, 2019 Amortized Cost Basis Estimated Fair Value Due in one year or less $ 59,626 $ 59,623 Due between one and five years — — $ 59,626 $ 59,623

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2019
Fair Value Disclosures [Abstract]
Schedule of Financial Assets Measured at Fair Value on a Recurring Basis	The following tables represent the Company’s financial assets measured at fair value on a recurring basis categorized by the fair value hierarchy as of March 31, 2019 and December 31, 2018 (in thousands): As of March 31, 2019 Level 1 Level 2 Level 3 Total Financial asset— available-for-sales securities Money market funds $ 736 $ — $ — $ 736 Commercial paper — 10,938 — 10,938 Corporate bonds — 45,967 — 45,967 U.S. government securities — 1,982 — 1,982 Total financial asset—available-for-sales securities $ 736 $ 58,887 $ — $ 59,623 As of December 31, 2018 Level 1 Level 2 Level 3 Total Financial asset— available-for-sales securities Money market funds $ 403 $ — $ — $ 403 Commercial paper — 10,164 — 10,164 Corporate bonds — 52,334 — 52,334 U.S. government securities — 1,972 — 1,972 Total financial asset—available-for-sales securities $ 403 $ 64,470 $ — $ 64,873

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
Schedule of Aggregate Future Non-Cancelable Minimum Rental Payments on Operating Leases Under ASC 840	As previously disclosed in our Annual Report on Form 10-K for the year ended December 31, 2018 and under the previous lease accounting standard ASC 840, the aggregate future non-cancelable minimum rental payments on our operating leases, as of December 31, 2018, were as follows (in thousands): Total Operating Purchase Lease and Purchase Leases Obligations Obligations 2019 $ 1,482 $ 15,674 $ 17,156 2020 1,516 4,247 5,763 2021 1,993 1,008 3,001 2022 2,033 — 2,033 2023 and thereafter 2,217 — 2,217 Total $ 9,241 $ 20,929 $ 30,170

Common Stock and Share-based _2

Common Stock and Share-based Compensation (Tables)	3 Months Ended
	Mar. 31, 2019
Equity [Abstract]
Summary of Activity under Stock Option Plan	Activity under the Company’s stock option plan is set forth below: Weighted- Weighted Average Average Remaining Aggregate Exercise Contractual Intrinsic Value Number of Shares Price Term (Years) (in thousands) Balance—December 31, 2018 2,297,403 $ 4.49 6.9 $ 9,858 Granted — $ — Exercised (132,692 ) $ 2.95 Canceled (7,981 ) $ 6.26 Balance—March 31, 2019 2,156,730 $ 4.58 6.8 $ 9,683 Vested and exercisable—March 31, 2019 1,524,974 $ 3.93 6.4 $ 7,842 Vested and exercisable—December 31, 2018 1,547,754 $ 3.74 6.5 $ 7,803
Summary of Activity under Company's RSU	Activity under the Company’s RSU is set forth below : Weighted Average Market Number of Shares Value Balance—December 31, 2018 1,554,089 $ 12.73 Granted 670,941 $ 8.51 Released (325,436 ) $ 12.76 Canceled (14,010 ) $ 12.22 Balance—March 31, 2019 1,885,584 $ 11.02
Schedule of Stock-Based Compensation Expense	Stock-based compensation expense recognized in the consolidated statements of operations and comprehensive loss for options, restricted stock units and ESPP was as follows (in thousands): Three Months Ended March 31, 2019 2018 Cost of revenue $ 66 $ 25 Research and development 1,232 573 Sales and marketing 350 111 General and administrative 642 269 Total $ 2,290 $ 978

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	3 Months Ended
	Mar. 31, 2019
Earnings Per Share [Abstract]
Summary of Computation of Basic and Diluted Net Loss Per Share Attributable to Common Shareholders	The following table summarizes the computation of basic and diluted net loss per share (in thousands, except per share data): Three Month Ended March 31, 2019 2018 Net loss $ (13,067 ) $ (1,368 ) Weighted-average common shares outstanding 35,158,470 33,494,807 Less: Shares subject to repurchase — — Weighted-average shares outstanding 35,158,470 33,494,807 Net loss per share, basic and diluted $ (0.37 ) $ (0.04 )
Summary of Potentially Dilutive Securities Outstanding Excluded from Computation of Diluted Weighted-average Shares Outstanding	The following potentially dilutive securities outstanding have been excluded from the computation of diluted weighted-average shares outstanding because such securities have an antidilutive impact due to losses reported (in common stock equivalent shares): As of As of March 31, December 31, 2019 2018 Stock options to purchase common stock 2,156,730 2,297,403 Unvested restricted stock units 1,885,584 1,554,089 Common stock warrants 83,695 83,695 Total 4,126,009 3,935,187

Segment Reporting (Tables)

Segment Reporting (Tables)	3 Months Ended
	Mar. 31, 2019
Segment Reporting [Abstract]
Schedule of Revenue from Segments	The following table summarizes revenue by market (in thousands): Three Months Ended March 31, 2019 2018 Revenue by market: Data Center $ 8,211 $ 16,269 Enterprise Infrastructure 5,471 9,511 Access 3,206 2,531 Automotive 134 47 Total revenue $ 17,022 $ 28,358
Schedule of Geographical Distribution of Revenue	The geographical distribution of revenue as a percentage of total revenue for the periods indicated was as follows: Three Months Ended March 31, 2019 2018 Malaysia 42 % 62 % China 32 22 United States 8 1 Other 18 15 Total 100 % 100 %

Concentrations (Tables)

Concentrations (Tables)	3 Months Ended
	Mar. 31, 2019
Risks And Uncertainties [Abstract]
Schedule of Customer Concentration as Percentage of Accounts Receivable and Total Revenue	Revenue and accounts receivable concentrated with significant customers and their manufacturing subcontractors as a percentage of accounts receivable and total revenue were as follows: As of As of March 31, December 31, 2019 2018 Accounts Receivable: Customer A 34 % 42 % Customer B 8 19 Three Months Ended March 31, 2019 2018 Revenue: Customer A 40 % 55 % Customer B 16 28

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Details) $ in Thousands	Mar. 31, 2019USD ($)
Summary Of Significant Accounting Policy [Line Items]
Lease term	12 months
Operating lease assets, net	$ 5,644
Lease liabilities	$ 7,090
ASU 2016-02
Summary Of Significant Accounting Policy [Line Items]
Lease term	12 months
Operating lease assets, net	$ 5,900
Lease liabilities	7,300
Operating lease incentives and deferred rent reduced right-of-use asset	$ 1,400

Balance Sheet Components - Sche

Balance Sheet Components - Schedule of Inventories (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Inventory Disclosure [Abstract]
Processed wafers	$ 1,277	$ 1,233
Work in process	7,445	5,990
Finished goods	8,293	7,251
Total inventories	$ 17,015	$ 14,474

Balance Sheet Components - Sc_2

Balance Sheet Components - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 30,062	$ 26,661
Less: accumulated depreciation and amortization	(18,851)	(17,436)
Property and equipment, net	11,211	9,225
Machinery and Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 15,925	15,237
Machinery and Equipment | Minimum
Property Plant And Equipment [Line Items]
Property and equipment, estimated useful lives	2 years
Machinery and Equipment | Maximum
Property Plant And Equipment [Line Items]
Property and equipment, estimated useful lives	3 years
Production Masks
Property Plant And Equipment [Line Items]
Property and equipment, estimated useful lives	4 years
Property and equipment, gross	$ 8,101	5,401
Software and Computer Equipment
Property Plant And Equipment [Line Items]
Property and equipment, estimated useful lives	3 years
Property and equipment, gross	$ 4,459	4,492
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, estimated useful lives	Shorter of estimated life of asset or remaining lease term
Property and equipment, gross	$ 1,414	1,414
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property and equipment, estimated useful lives	3 years
Property and equipment, gross	$ 163	$ 117

Balance Sheet Components - Addi

Balance Sheet Components - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Balance Sheets Components [Line Items]
Depreciation and amortization of property and equipment	$ 1,400	$ 1,200
Amortization of intangible assets	$ 200	$ 200
Lease term	12 months
Option to extend, existence, operating lease	true
Operating lease right-of-use assets	$ 5,644
Operating lease liability	7,090
Lease cost	$ 500
Operating lease weighted average remaining lease term	3 years 3 months 18 days
Operating lease weighted average discount rate	8.50%
Minimum
Balance Sheets Components [Line Items]
Lease term	1 year
Operating lease renewal term	1 year
Maximum
Balance Sheets Components [Line Items]
Lease term	6 years
Operating lease renewal term	9 years

Balance Sheet Components - Sc_3

Balance Sheet Components - Schedule of Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Finite Lived Intangible Assets [Line Items]
Intangible assets, gross	$ 5,764	$ 5,764
Less: accumulated amortization	(2,218)	(2,016)
Intangible assets, net	$ 3,546	3,748
IP license
Finite Lived Intangible Assets [Line Items]
Intangible assets, estimated useful lives	7 years
Intangible assets, gross	$ 5,416	5,416
Patents
Finite Lived Intangible Assets [Line Items]
Intangible assets, gross	$ 348	$ 348
Patents | Minimum
Finite Lived Intangible Assets [Line Items]
Intangible assets, estimated useful lives	10 years
Patents | Maximum
Finite Lived Intangible Assets [Line Items]
Intangible assets, estimated useful lives	12 years

Balance Sheet Components - Sc_4

Balance Sheet Components - Schedule of Amortization Expense Related to Amortizable Intangibles In Future Periods (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Finite Lived Intangible Assets Future Amortization Expense [Abstract]
2019 (remaining)	$ 606
2020	808
2021	808
2022	800
2023 and thereafter	524
Intangible assets, net	$ 3,546	$ 3,748

Balance Sheet Components - Sc_5

Balance Sheet Components - Schedule of Maturities of Lease Liabilities (Details) $ in Thousands	Mar. 31, 2019USD ($)
Leases [Abstract]
2019 (remaining)	$ 1,020
2020	1,513
2021	2,018
2022	2,059
2023	1,793
2024 and thereafter	431
Total	8,834
Less imputed interest	(1,744)
Operating lease liability	$ 7,090

Balance Sheet Components - Sc_6

Balance Sheet Components - Schedule of Accrued Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Accrued Liabilities Current [Abstract]
Accrued compensation and related benefits	$ 4,759	$ 5,301
Customer Deposit		40
Accrued IP License	5,266	4,829
Accrued technical consulting and professional services	237	412
Accrued royalty, rebates and commission	583	443
Other accrued liabilities	4,905	2,882
Total accrued liabilities	$ 15,750	$ 13,907

Financial Instruments - Summary

Financial Instruments - Summary of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Schedule Of Available For Sale Securities [Line Items]
Cost	$ 59,626	$ 64,996
Gross Unrealized Gains	2
Gross Unrealized Losses	(5)	(123)
Estimated Fair Values	59,623	64,873
Commercial Paper
Schedule Of Available For Sale Securities [Line Items]
Cost	10,939	10,173
Gross Unrealized Losses	(1)	(9)
Estimated Fair Values	10,938	10,164
Money Market Fund
Schedule Of Available For Sale Securities [Line Items]
Cost	736	403
Estimated Fair Values	736	403
Corporate Bonds
Schedule Of Available For Sale Securities [Line Items]
Cost	45,971	52,448
Gross Unrealized Losses	(4)	(114)
Estimated Fair Values	45,967	52,334
U.S. Government Securities
Schedule Of Available For Sale Securities [Line Items]
Cost	1,980	1,972
Gross Unrealized Gains	2
Estimated Fair Values	1,982	1,972
Cash and Cash Equivalents
Schedule Of Available For Sale Securities [Line Items]
Estimated Fair Values	5,728	4,143
Short-term Investments
Schedule Of Available For Sale Securities [Line Items]
Estimated Fair Values	$ 53,895	$ 60,730

Financial Instruments - Summa_2

Financial Instruments - Summary of Contractual Maturities of Available-for-sale Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Amortized Cost Basis
Due in one year or less	$ 59,626
Cost	59,626	$ 64,996
Estimated Fair Values
Due in one year or less	59,623
Total	$ 59,623	$ 64,873

Financial Instruments - Additio

Financial Instruments - Additional Information (Details) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities, continuous loss position, 12 months or longer	$ 11,000,000	$ 19,200,000
Individual Securities
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities, continuous loss position, 12 months or longer	$ 0	$ 0

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Financial Assets Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total financial asset—available-for-sales securities	$ 59,623	$ 64,873
Corporate Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total financial asset—available-for-sales securities	45,967	52,334
Recurring Basis
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total financial asset—available-for-sales securities	59,623	64,873
Recurring Basis | Money Market Fund
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total financial asset—available-for-sales securities	736	403
Recurring Basis | Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total financial asset—available-for-sales securities	10,938	10,164
Recurring Basis | U.S. Government Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total financial asset—available-for-sales securities	1,982	1,972
Recurring Basis | Corporate Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total financial asset—available-for-sales securities	45,967	52,334
Recurring Basis | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total financial asset—available-for-sales securities	736	403
Recurring Basis | Level 1 | Money Market Fund
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total financial asset—available-for-sales securities	736	403
Recurring Basis | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total financial asset—available-for-sales securities	58,887	64,470
Recurring Basis | Level 2 | Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total financial asset—available-for-sales securities	10,938	10,164
Recurring Basis | Level 2 | U.S. Government Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total financial asset—available-for-sales securities	1,982	1,972
Recurring Basis | Level 2 | Corporate Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total financial asset—available-for-sales securities	$ 45,967	$ 52,334

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Transfers within hierarchy	$ 0	$ 0

Commitments and Contingencies -

Commitments and Contingencies - Schedule of Aggregate Future Non-Cancelable Minimum Rental Payments on Operating Leases Under ASC 840 (Details) $ in Thousands	Dec. 31, 2018USD ($)
Operating Leases
2019	$ 1,482
2020	1,516
2021	1,993
2022	2,033
2023 and thereafter	2,217
Total	9,241
Purchase Obligations
2019	15,674
2020	4,247
2021	1,008
Total	20,929
Total Lease and Purchase Obligations
2019	17,156
2020	5,763
2021	3,001
2022	2,033
2023 and thereafter	2,217
Total	$ 30,170

Commitments and Contingencies_2

Commitments and Contingencies - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Commitments And Contingencies Disclosure [Abstract]
Liability associated with indemnifications	$ 0	$ 0
Operating Leases, Indemnification Agreements, Description	Under the indemnification provisions of the Company’s standard sales-related contracts, the Company agrees to defend its customers against third-party claims asserting infringement of certain intellectual property rights, which may include patents, copyrights, trademarks, or trade secrets, and to pay judgments entered on such claims. Certain agreements include indemnification provisions that could potentially expose the Company to losses in excess of the amount received under the agreement. In addition, the Company indemnifies its directors and certain of its officers while they are serving in good faith in such capacities. To date, the Company has not incurred costs to defend lawsuits or settle claims related to these indemnification agreements.

Common Stock and Share-based _3

Common Stock and Share-based Compensation - Additional Information (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Nov. 30, 2017
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Common stock, shares authorized	95,000,000		95,000,000
Common stock, par value	$ 0.00001		$ 0.00001
Preferred stock, shares authorized	5,000,000		5,000,000
Preferred stock, par value	$ 0.00001		$ 0.00001
Preferred stock, shares outstanding	0
Dividends declared	$ 0
Unrecognized stock compensation costs	$ 1,700,000		$ 2,000,000
Unrecognized stock compensation costs recognition period	2 years 9 months 18 days		2 years 9 months 18 days
Aggregate intrinsic value of options exercised	$ 700,000		$ 7,100,000
Options granted	0	0
Weighted-average grant-date fair value of options granted			$ 5.46
Income tax benefit associated with stock-based compensation expense	$ 0	$ 0
2015 Equity Incentive Plan and 2004 Equity Incentive Plan | Incentive Stock Options
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Exercise price determination description	The exercise price of an option is determined by the board of directors when the option is granted and may not be less than 85% of the fair market value of the shares on the date of grant, provided that the exercise price of an ISO is not less than 100% of the fair market value of the shares on the date of grant and the exercise price of any option granted to a 10% stockholder is not less than 110% of the fair market value of the shares on the date of grant.
Exercise price per share	85.00%
Equity incentive plan expiration period	10 years
2015 Equity Incentive Plan and 2004 Equity Incentive Plan | Nonstatutory Stock Options
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Equity incentive plan expiration period	10 years
2017 Equity Incentive Plan
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Vesting period	4 years
Common shares reserved	5,047,440
Percentage of increase in common shares reserved	5.00%
Shares available for grant	3,444,533
Description of restricted stock unit awards conversion basis upon vesting	one-for-one
Number of shares reduced from shares available for issuance upon restricted stock unit awards grants	1
2017 Equity Incentive Plan | Restricted Stock Unit Awards
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Vesting period	4 years
Unrecognized stock compensation costs recognition period	3 years 1 month 6 days		3 years
Unamortized compensation expense to be recognized	$ 19,600,000		$ 15,800,000
ESPP
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Common shares reserved	1,000,000
Shares available for grant	191,446
Unrecognized stock compensation costs recognition period	2 months		5 months
Unamortized compensation expense to be recognized	$ 200,000		$ 500,000
Common stock shares authorized				2,018,975
Percentage of shares of capital stock outstanding	2.00%
Percentage of payroll deduction on eligible compensation	15.00%
Percentage of shares purchased at fair market value of common stock	85.00%
Shares issued under plan	366,369
Risk free interest rate	2.36%
Expected term	6 months
Expected dividends	0.00%
Volatility	22.00%
Share-based Compensation Award, Tranche One | 2015 Equity Incentive Plan and 2004 Equity Incentive Plan | Incentive Stock Options
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Vesting percentage	25.00%
Vesting period	12 months
Share-based Compensation Award, Tranche Two | 2015 Equity Incentive Plan and 2004 Equity Incentive Plan | Incentive Stock Options
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Vesting percentage	25.00%
Vesting period	12 months
Share-based Compensation Award, Tranche Three | 2015 Equity Incentive Plan and 2004 Equity Incentive Plan | Incentive Stock Options
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Vesting percentage	25.00%
Vesting period	12 months
Share Based Compensation Award Tranche Four | 2015 Equity Incentive Plan and 2004 Equity Incentive Plan | Incentive Stock Options
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Vesting percentage	25.00%
Vesting period	12 months
Maximum
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Common stock, shares authorized	95,000,000		95,000,000
Maximum | 2015 Equity Incentive Plan and 2004 Equity Incentive Plan | Incentive Stock Options
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Exercise price per share	100.00%
Maximum | 2015 Equity Incentive Plan and 2004 Equity Incentive Plan | Incentive Stock Options | 10% stockholder
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Exercise price per share	110.00%
Maximum | 2017 Equity Incentive Plan
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Exercise price per share	100.00%
Options granted exercise period	10 years
Maximum | 2017 Equity Incentive Plan | 10% stockholder
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Exercise price per share	110.00%

Common Stock and Share-based _4

Common Stock and Share-based Compensation - Summary of Activity under Stock Option Plan (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Granted	0	0
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Beginning balance	2,297,403
Exercised	(132,692)
Canceled	(7,981)
Ending balance	2,156,730		2,297,403
Vested and exercisable—March 31, 2019	1,524,974		1,547,754
Weighted average exercise price, beginning balance	$ 4.49
Weighted average exercise price, exercised	2.95
Weighted average exercise price, canceled	6.26
Weighted average exercise price, ending balance	4.58		$ 4.49
Weighted average exercise price, vested and exercisable	$ 3.93		$ 3.74
Weighted average remaining contractual term	6 years 9 months 18 days		6 years 10 months 24 days
Weighted average remaining contractual term, vested and exercisable	6 years 4 months 24 days		6 years 6 months
Aggregate intrinsic value	$ 9,683		$ 9,858
Aggregate intrinsic value, vested and exercisable	$ 7,842		$ 7,803

Common Stock and Share-based _5

Common Stock and Share-based Compensation - Summary of Activity under Company's RSU (Details) - Restricted Stock Unit Awards	3 Months Ended
	Mar. 31, 2019$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, beginning balance | shares	1,554,089
Number of Shares, Granted | shares	670,941
Number of Shares, Released | shares	(325,436)
Number of Shares, Canceled | shares	(14,010)
Number of Shares, ending balance | shares	1,885,584
Weighted Average Market Value, beginning balance | $ / shares	$ 12.73
Weighted Average Market Value, Granted | $ / shares	8.51
Weighted Average Market Value, Released | $ / shares	12.76
Weighted Average Market Value, Canceled | $ / shares	12.22
Weighted Average Market Value, ending balance | $ / shares	$ 11.02

Common Stock and Share-based _6

Common Stock and Share-based Compensation - Schedule of Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 2,290	$ 978
Cost of Revenue
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	66	25
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	1,232	573
Sales and Marketing
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	350	111
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 642	$ 269

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Provision for (benefit from) income taxes	$ 190	$ (125)

Net Loss Per Share - Summary of

Net Loss Per Share - Summary of Computation of Basic and Diluted Net Loss Per Share Attributable to Common Shareholders (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Earnings Per Share [Abstract]
Net loss	$ (13,067)	$ (1,368)
Weighted-average common shares outstanding	35,158,470	33,494,807
Weighted-average shares outstanding	35,158,470	33,494,807
Net loss per share, basic and diluted	$ (0.37)	$ (0.04)

Net Loss Per Share - Summary _2

Net Loss Per Share - Summary of Potentially Dilutive Securities Outstanding Excluded from Computation of Diluted Weighted-average Shares Outstanding (Details) - shares	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential dilutive securities outstanding excluded from computation of diluted weighted-average shares outstanding	4,126,009	3,935,187
Incentive Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential dilutive securities outstanding excluded from computation of diluted weighted-average shares outstanding	2,156,730	2,297,403
Unvested Restricted Stock Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential dilutive securities outstanding excluded from computation of diluted weighted-average shares outstanding	1,885,584	1,554,089
Common Stock Warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential dilutive securities outstanding excluded from computation of diluted weighted-average shares outstanding	83,695	83,695

Segment Reporting (Details)

Segment Reporting (Details)	3 Months Ended
	Mar. 31, 2019Segment
Segment Reporting [Abstract]
Number of reportable segments	1

Segment Reporting - Schedule of

Segment Reporting - Schedule of Revenue from Segments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Segment Reporting Information [Line Items]
Revenue	$ 17,022	$ 28,358
Data Center
Segment Reporting Information [Line Items]
Revenue	8,211	16,269
Enterprise Infrastructure
Segment Reporting Information [Line Items]
Revenue	5,471	9,511
Access
Segment Reporting Information [Line Items]
Revenue	3,206	2,531
Automotive
Segment Reporting Information [Line Items]
Revenue	$ 134	$ 47

Segment Reporting - Schedule _2

Segment Reporting - Schedule of Geographical Distribution of Revenue (Details) - Revenue - Geographic Concentration Risk	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenues From External Customers And Long Lived Assets [Line Items]
Percentage of revenue	100.00%	100.00%
Malaysia
Revenues From External Customers And Long Lived Assets [Line Items]
Percentage of revenue	42.00%	62.00%
China
Revenues From External Customers And Long Lived Assets [Line Items]
Percentage of revenue	32.00%	22.00%
United States
Revenues From External Customers And Long Lived Assets [Line Items]
Percentage of revenue	8.00%	1.00%
Other
Revenues From External Customers And Long Lived Assets [Line Items]
Percentage of revenue	18.00%	15.00%

Concentrations - Additional Inf

Concentrations - Additional Information (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Risks And Uncertainties [Abstract]
Amounts held on deposit at financial institutions in excess of FDIC insured limits	$ 0.6	$ 1.1

Concentrations - Schedule of Cu

Concentrations - Schedule of Customer Concentration as Percentage of Accounts Receivable and Total Revenue (Details) - Customer Concentration Risk	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Accounts Receivable | Customer A
Concentration Risk [Line Items]
Concentration risk, percentage	34.00%		42.00%
Accounts Receivable | Customer B
Concentration Risk [Line Items]
Concentration risk, percentage	8.00%		19.00%
Revenue | Customer A
Concentration Risk [Line Items]
Concentration risk, percentage	40.00%	55.00%
Revenue | Customer B
Concentration Risk [Line Items]
Concentration risk, percentage	16.00%	28.00%

Employee Benefit Plan - Additio

Employee Benefit Plan - Additional Information (Details)	3 Months Ended
	Mar. 31, 2019USD ($)
401 (k)
Defined Contribution Plan Disclosure [Line Items]
Company contribution	$ 0

Subsequent Event - Additional I

Subsequent Event - Additional Information (Details) - Marvell Technology Group Ltd - Subsequent Event	May 06, 2019$ / shares
Subsequent Event [Line Items]
Merger agreement date	May 6, 2019
Common Stock
Subsequent Event [Line Items]
Per share in cash paid under the agreement	$ 13.25