Penumbra (PEN) 10-K 8 Mar 16 2015 FY Annual report Financial data

Document and Entity Information

Document and Entity Information Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2015	Jan. 31, 2016	Jun. 30, 2015
Document and Entity Information [Abstract]
Entity Registrant Name	Penumbra Inc
Entity Central Index Key	1,321,732
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2015
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		29,978,983
Entity Current Reporting Status	Yes
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Public Float			$ 0

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 19,547	$ 3,290
Marketable investments	129,257	48,253
Accounts receivable, net of doubtful accounts of $589 and $602 at December 31, 2015 and 2014, respectively	29,444	18,912
Inventories	56,761	33,451
Deferred taxes	0	6,280
Prepaid expenses and other current assets	9,352	5,115
Total current assets	244,361	115,301
Property and equipment, net	8,951	5,181
Deferred taxes	10,143	571
Other non-current assets	393	328
Total assets	263,848	121,381
Current Liabilities:
Accounts payable	2,567	2,348
Accrued liabilities	25,581	18,475
Total current liabilities	28,148	20,823
Other non-current liabilities	3,178	1,461
Total liabilities	$ 31,326	$ 22,284
Commitments and contingencies
Convertible preferred stock, $0.001 par value per share—none authorized, issued and outstanding at December 31, 2015; 25,000,000 shares authorized, 19,510,410 shares issued and outstanding at December 31, 2014; aggregate liquidation value $149,361 at December 31, 2014	$ 0	$ 111,467
Stockholders’ Equity (Deficit):
Preferred stock, $0.001 par value per share—5,000,000 shares authorized, none issued and outstanding at December 31, 2015; None authorized, issued and outstanding at December 31, 2014	0	0
Common stock, $0.001 par value per share—300,000,000 shares authorized, 29,897,860 issued and outstanding at December 31, 2015; 40,000,000 shares authorized, 4,736,689 issued and outstanding at December 31, 2014	30	5
Additional paid-in capital	252,087	8,446
Notes receivable from stockholders	(5)	(117)
Accumulated other comprehensive loss	(2,115)	(864)
Accumulated deficit	(17,475)	(19,840)
Total stockholders’ equity (deficit)	232,522	(12,370)
Total liabilities, convertible preferred stock and stockholders’ equity (deficit)	$ 263,848	$ 121,381

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 589	$ 602
Convertible preferred stock, par value (in dollars per share)		$ 0.001
Convertible preferred stock, shares authorized	0	25,000,000
Convertible preferred stock, shares issued	0	19,510,410
Convertible preferred stock, shares outstanding	0	19,510,410
Convertible preferred stock, aggregate liquidation amount		$ 149,361
Preferred stock, par value (in dollars per share)	$ 0.001
Preferred stock, shares authorized	5,000,000	0
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	300,000,000	40,000,000
Common stock, shares issued	29,897,860	4,736,689
Common stock, shares outstanding	29,897,860	4,736,689

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Statement [Abstract]
Revenue	$ 186,095	$ 125,510	$ 88,848
Cost of revenue	62,037	42,668	30,972
Gross profit	124,058	82,842	57,876
Operating expenses:
Research and development	18,027	15,575	14,084
Sales, general and administrative	101,852	64,258	44,918
Total operating expenses	119,879	79,833	59,002
Income (loss) from operations	4,179	3,009	(1,126)
Interest income (expense), net	541	439	345
Other income (expense), net	(696)	(309)	(474)
Income (loss) before provision for (benefit from) income taxes	4,024	3,139	(1,255)
Provision for (benefit from) income taxes	1,659	894	(5,354)
Net income	2,365	2,245	4,099
Foreign currency translation adjustments, net of tax	(1,308)	(1,423)	(522)
Unrealized gains (losses) on available-for-sale securities, net of tax	57	(237)	(84)
Comprehensive income	1,114	585	3,493
Net income (loss) attributable to common stockholders	$ 1,084	$ (833)	$ 887
Net income (loss) per share attributable to common stockholders—Basic (in USD per share)	$ 0.09	$ (0.18)	$ 0.21
Net income (loss) per share attributable to common stockholders—Diluted (in USD per share)	$ 0.08	$ (0.18)	$ 0.14
Weighted average shares used to compute net income (loss) per share attributable to common stockholders—Basic (in shares)	11,993,429	4,609,375	4,304,396
Weighted average shares used to compute net income (loss) per share attributable to common stockholders—Diluted (in shares)	14,219,650	4,609,375	6,500,835

Consolidated Statements of Conv

Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Convertible Preferred Stock	Common Stock	Additional Paid-in Capital	Notes Receivable from Stockholders	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Convertible Preferred Stock	Convertible Preferred StockAccumulated Deficit
Beginning balance at Dec. 31, 2012		$ 56,222
Beginning balance, shares at Dec. 31, 2012		15,594,618
Ending balance at Dec. 31, 2013		$ 56,222
Ending balance, shares at Dec. 31, 2013		15,594,618
Beginning balance at Dec. 31, 2012	$ (12,751)		$ 4	$ 5,073	$ (138)	$ 1,402	$ (19,092)
Beginning balance, shares at Dec. 31, 2012			4,192,745
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock	310			310
Issuance of common stock, shares			198,843
Stock-based compensation	886			886
Foreign currency translation adjustment, net of tax	(522)					(522)
Unrealized gain (loss) on investments, net of tax	(84)					(84)
Net income	4,099						4,099
Ending balance at Dec. 31, 2013	(8,062)		$ 4	6,269	(138)	796	(14,993)
Ending balance, shares at Dec. 31, 2013			4,391,588
Increase (Decrease) in Temporary Equity [Roll Forward]
Issuance of Series F preferred stock, net of issuance cost of $2,788		$ 57,212
Issuance of Series F preferred stock, net of issuance cost of $2,788, shares		4,545,455
Repurchase of preferred stock		$ (1,967)						$ (6,344)	$ (6,344)
Repurchase of preferred stock, shares		(629,663)
Ending balance at Dec. 31, 2014	$ 111,467	$ 111,467
Ending balance, shares at Dec. 31, 2014	19,510,410	19,510,410
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock	$ 1,037		$ 1	1,036
Issuance of common stock, shares			460,713
Repurchase of common stock	(1,040)			(292)			(748)
Repurchase of common stock, shares			(115,612)
Stock-based compensation	1,433			1,433
Forgiven notes receivable from stockholders	21				21
Foreign currency translation adjustment, net of tax	(1,423)					(1,423)
Unrealized gain (loss) on investments, net of tax	(237)					(237)
Net income	2,245						2,245
Ending balance at Dec. 31, 2014	(12,370)		$ 5	8,446	(117)	(864)	(19,840)
Ending balance, shares at Dec. 31, 2014			4,736,689
Increase (Decrease) in Temporary Equity [Roll Forward]
Conversion of convertible preferred stock into common stock upon closing of IPO		$ (111,467)
Conversion of convertible preferred stock into common stock upon closing of IPO, shares		(19,510,410)
Ending balance at Dec. 31, 2015	$ 0	$ 0
Ending balance, shares at Dec. 31, 2015	0	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of convertible preferred stock into common stock upon closing of IPO	$ 111,467		$ 19	111,448
Conversion of convertible preferred stock into common stock upon closing of IPO, shares			19,510,410
Shares issued upon closing of IPO	124,742		$ 5	124,737
Shares issued upon closing of IPO, shares			4,600,000
Issuance of common stock	1,126		$ 1	1,125
Issuance of common stock, shares			1,074,411
Shares held for tax withholdings	(2,525)			(2,525)
Repurchase of common stock	(342)			(342)
Repurchase of common stock, shares			(23,650)
Stock-based compensation	7,608			7,608
Excess tax benefit from stock-based compensation	1,590			1,590
Forgiven notes receivable from stockholders	91				91
Note received from a stockholder	21				21
Foreign currency translation adjustment, net of tax	(1,308)					(1,308)
Unrealized gain (loss) on investments, net of tax	57					57
Net income	2,365						2,365
Ending balance at Dec. 31, 2015	$ 232,522		$ 30	$ 252,087	$ (5)	$ (2,115)	$ (17,475)
Ending balance, shares at Dec. 31, 2015			29,897,860

Consolidated Statement of Conve

Consolidated Statement of Convertible Preferred Stock and Stockholders’ Equity (Deficit) (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Stockholders' Equity [Abstract]
Issuance of Series F preferred stock, issuance cost		$ 2,788
Foreign currency translation adjustment, tax	$ 117	245	$ 213
Unrealized gain on investments, tax	$ 66	$ 168	$ 10

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 2,365	$ 2,245	$ 4,099
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation and amortization	1,752	751	677
Amortization of premium on marketable investments	83	0	0
Stock-based compensation	7,271	1,433	886
Excess tax benefit from stock-based compensation	(1,590)	0	0
Provision for doubtful accounts	(13)	150	259
Inventory write downs	1,163	1,852	892
Write off of note receivable	91	21	0
Provision for sales returns	1,083	(3)	(212)
Loss on minority investment	0	150	0
Loss on disposal of property and equipment	43	21	3
Realized loss on marketable investments	541	0	160
Provision for product warranty	399	(8)	0
Release of valuation allowance	(243)	(321)	(4,962)
Deferred taxes	(2,961)	(571)	(335)
Issuance of common stock to third parties	0	0	132
Changes in operating assets and liabilities:
Accounts receivable	(11,063)	(7,426)	(1,550)
Inventories	(25,126)	(9,444)	(3,779)
Prepaid expenses and other current and non-current assets	(4,013)	(1,906)	(961)
Accounts payable	132	1,299	(451)
Accrued expenses and other non-current liabilities	7,807	5,368	1,746
Net cash used in operating activities	(22,279)	(6,389)	(3,396)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of marketable investments	(135,340)	(51,342)	(6,858)
Proceeds from sales of marketable investments	54,998	18,229	6,405
Purchases of property and equipment	(5,474)	(3,888)	(798)
Net cash used in investing activities	(85,816)	(37,001)	(1,251)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of preferred stock, net of issuance costs	0	57,212	0
Proceeds from issuance of common stock issued in initial public offering, net of issuance costs	124,742	0	0
Proceeds from exercises of stock options	617	1,036	178
Excess tax benefit from stock-based compensation	1,590	0	0
Repurchase of preferred stock	0	(8,311)	0
Proceeds from credit facility	0	0	2,000
Repayment of credit facility	0	(6,000)	0
Repurchase of common stock and stock options	0	(1,040)	0
Payment of employee taxes related to vested common and restricted stock	(2,525)	0	0
Net cash provided by financing activities	124,424	42,897	2,178
Effect of foreign exchange rate changes on cash and cash equivalents	(72)	(348)	(835)
NET INCREASE IN CASH AND CASH EQUIVALENTS	16,257	(841)	(3,304)
CASH AND CASH EQUIVALENTS—Beginning of period	3,290	4,131	7,435
CASH AND CASH EQUIVALENTS—End of period	19,547	3,290	4,131
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Cash paid for interest	1	160	100
Cash paid for income taxes	1,220	3,086	37
NONCASH INVESTING AND FINANCING ACTIVITIES:
Conversion of convertible preferred stock into common stock	111,467	0	0
Purchase of property and equipment funded through accounts payable	$ 143	$ 44	$ 5

Organization and Description of

Organization and Description of Business	12 Months Ended
	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of Business	Organization and Description of Business Penumbra, Inc. (the Company) is a global interventional therapies company that designs, develops, manufactures and markets innovative medical devices. The Company has a broad portfolio of products that addresses challenging medical conditions and significant clinical needs across two major markets, neuro and peripheral vascular. The conditions that the Company’s products address include, among others, ischemic stroke, hemorrhagic stroke and various peripheral vascular conditions that can be treated through thrombectomy and embolization procedures.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation and Consolidation The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (U.S. GAAP). The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities and equity accounts; disclosure of contingent assets and liabilities at the date of the financial statements; and the reported amounts of revenues and expenses during the reporting period. On an ongoing basis, the Company evaluates its estimates, including those related to provisions for doubtful accounts, sales return reserve, warranty reserves, valuation of inventories, useful lives of property and equipment, income taxes, the valuation of equity instruments and contingencies, among others. The Company bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other data. Actual results could differ from those estimates. Segments The Company determined its operating segment on the same basis that it uses to evaluate its performance internally. The Company has one business activity: the design, development, manufacturing and marketing of innovative medical devices, and operates as one operating segment. The Company’s chief operating decision-maker, its Chief Executive Officer, reviews its operating results for the purpose of allocating resources and evaluating financial performance. The Company determines revenue by geographic area, based on the destination to which it ships its products. Foreign Currency Translation The Company’s consolidated financial statements are prepared in United States Dollars (USD). Its foreign subsidiaries use their local currency as their functional currency and maintain their records in the local currency. Accordingly, the assets and liabilities of these subsidiaries are translated into USD using the current exchange rates in effect at the balance sheet date and equity accounts are translated into USD using historical rates. Revenues and expenses are translated using the average exchange rates in effect for the year involved. The resulting foreign currency translation adjustments are recorded in accumulated other comprehensive income in the consolidated balance sheets. Transactions denominated in foreign currency are translated at exchange rates at the date of transaction with foreign currency gains (losses) recorded in other income (expense), net in the consolidated statements of operations and comprehensive income. The Company recognized net foreign currency transaction losses of $0.1 million , $0.3 million and $0.3 million during the years ended December 31, 2015 , 2014 and 2013 , respectively. As the Company’s international operations grow, its risks associated with fluctuation in currency rates will become greater, and the Company will continue to reassess its approach to managing this risk. In addition, currency fluctuations or a weakening USD can increase the costs of the Company’s international expansion. To date, the Company has not entered into any foreign currency hedging contracts, since exchange rate fluctuations have not had a material impact on its operating results and cash flows. Concentration of Credit Risk Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash and cash equivalents, marketable investments and accounts receivable. The majority of the Company’s cash is held by one financial institution in the U. S. in excess of federally insured limits. The Company maintained investments in money market funds that were not federally insured during the year ended December 31, 2015 and held cash in foreign banks of approximately $1.9 million and $0.8 million at December 31, 2015 and 2014 , respectively, that was not federally insured. All of the Company’s revenue has been derived from sales of its products in the U. S. and international markets. The Company uses both its own salesforce and independent distributors to sell its products. Concentrations of credit risk with respect to accounts receivable are limited due to the large number of entities comprising the Company’s customer base. The Company performs ongoing credit evaluations of its customers, including its distributors, does not require collateral, and maintains allowances for potential credit losses on customer accounts when deemed necessary. During the years ended December 31, 2015 , 2014 and 2013 , one customer (a distributor) accounted for 10% , 12% and 14% , respectively, of the Company’s revenue. No customer accounted for greater than 10% of the Company’s accounts receivable balance as of December 31, 2015 or 2014 . Significant Risks and Uncertainties The Company is subject to risks common to medical device companies including, but not limited to, new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with government regulations, product liability, uncertainty of market acceptance of products and the potential need to obtain additional financing. The Company is dependent on third party suppliers, in some cases single-source suppliers. There can be no assurance that the Company’s products will continue to be accepted in the marketplace, nor can there be any assurance that any future products can be developed or manufactured at an acceptable cost and with appropriate performance characteristics, or that such products will be successfully marketed, if at all. The Company’s products require approval or clearance from the U.S. Food and Drug Administration prior to commencing commercial sales in the U. S. . There can be no assurance that the Company’s products will receive all of the required approvals or clearances. Approvals or clearances are also required in foreign jurisdictions in which the Company sells its products. If the Company is denied such approvals or clearances or such approvals or clearances are delayed, it may have a material adverse impact on the Company’s results of operations, financial position and liquidity. Fair Value of Financial Instruments Carrying amounts of certain of the Company’s financial instruments, including cash equivalents, accounts receivable, prepaid expenses and other current assets, accounts payable and accrued liabilities, approximate fair value due to their relatively short maturities. Cash, Cash Equivalents and Marketable Investments The Company invests its cash primarily in money market funds and in highly liquid debt instruments of U.S. federal and municipal governments, and their agencies, and corporate debt securities. All highly liquid investments with stated maturities of three months or less from the date of purchase are classified as cash equivalents; all highly liquid investments with stated maturities of greater than three months are classified as marketable investments. The majority of the Company’s cash and investments are held in U.S. banks. The Company determines the appropriate classification of its investments in marketable investments at the time of purchase and re-evaluates such designation at each balance sheet date. The Company’s marketable investments have been classified and accounted for as available-for-sale. Investments with remaining maturities of more than one year are viewed by the Company as available to support current operations and are classified as current assets under the caption marketable investments in the accompanying consolidated balance sheets. Investments in marketable investments are carried at fair value, with the unrealized gains and losses reported as a component of accumulated other comprehensive loss. Any realized gains or losses on the sale of marketable investments are determined on a specific identification method, and such gains and losses are reflected as a component of other income (expense), net. Impairment of Marketable Investments After determining the fair value of available-for-sale debt instruments, unrealized gains or losses on these securities are recorded to accumulated other comprehensive income (loss) until either the security is sold or the Company determines that the decline in value is other-than-temporary. The primary differentiating factors that the Company considers in classifying impairments as either temporary or other-than-temporary impairments is the intent and ability to retain the investment in the issuer for a period of time sufficient to allow for any anticipated recovery in market value, the length of the time and the extent to which the market value of the investment has been less than cost, the financial condition and near-term prospects of the issuer. There were no other-than-temporary impairments for the years ended December 31, 2015 , 2014 or 2013 . Accounts Receivable Accounts receivable are stated at invoice value less estimated allowances for doubtful accounts. The Company continually monitors customer payments and maintains a reserve 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, and thereby reduces the net recognized receivable to the amount reasonably believed to be collectible. Inventories Inventories are stated at the lower of cost (determined under the first-in first-out method) or market. Write downs are provided for raw materials, components or finished goods that are determined to be excessive or obsolete. Market value is determined as the lower of replacement cost or net realizable value. The Company regularly reviews inventory quantities in consideration of actual loss experience, projected future demand and remaining shelf life to record a provision for excess and obsolete inventory when appropriate. The estimate of excess quantities is subjective and primarily dependent on the Company’s estimates of future demand for a particular product or components or raw materials used in the manufacturing of such product. If the estimate of future demand is inaccurate based on actual sales, the Company may increase the write down for excess inventory and record a charge to inventory impairment in the accompanying consolidated statements of operations and comprehensive income. The Company periodically evaluates the carrying value of inventory on hand for potential excess amounts over demand using the same lower of cost or market approach that has been used to value the inventory. The Company also periodically evaluates inventory quantities in consideration of actual loss experience. As a result of these evaluations, the Company recognized total write downs of $1.2 million , $1.9 million and $0.9 million for the years ended December 31, 2015 , 2014 and 2013 , respectively. Property and Equipment, net Property and equipment are stated at cost less accumulated depreciation. Depreciation is computed using the straight-line method over five years, which is the estimated useful lives of the assets. Leasehold improvements are amortized using the straight-line method over the shorter of the lease term or estimated useful life. Upon retirement or sale, the cost and the related accumulated depreciation are removed from the consolidated balance sheet and the resulting gain or loss is reflected in operations. Maintenance and repairs are charged to operations as incurred. Impairment of Long-Lived Assets The Company reviews long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. When such an event occurs, management determines whether there has been impairment by comparing the anticipated undiscounted future net cash flows to the related asset group’s carrying value. If an asset is considered impaired, the asset is written down to fair value, which is determined based either on discounted cash flows or appraised value, depending on the nature of the asset. There was no impairment of long-lived assets during the years ended December 31, 2015 , 2014 or 2013 . Convertible Preferred Stock The Company, prior to the closing of its initial public offering (IPO) on September 23, 2015, classified its outstanding convertible preferred stock as temporary equity in the consolidated balance sheet due to the existence of certain change in control events that were not solely within the Company’s control, including liquidation, sale or transfer of the Company, that could trigger the ability of the holders of the convertible preferred stock to call for redemption of shares. Upon the closing of the IPO, all outstanding shares of convertible preferred stock automatically converted into shares of common stock on a one -for-one basis. Revenue Recognition Revenue is comprised of product revenue net of returns, discounts, administration fees and sales rebates. The Company recognizes revenue when persuasive evidence of an arrangement exists, delivery has occurred, the sales price is fixed or determinable and collectability is reasonably assured. Evidence of an arrangement consists of customer orders and the Company typically considers delivery to have occurred once title and risk of loss has been transferred and the product has been delivered to the customer. The Company typically recognizes revenue when products are delivered to hospital customers or distributors. However, with respect to products that the Company consigns to hospitals, which primarily consist of coils, the Company recognizes revenue at the time hospitals utilize products in a procedure. Deferred revenue represents amounts that the Company has already invoiced its customers and that are ultimately expected to be recognized as revenue, but for which not all revenue recognition criteria have been met. The Company had a deferred revenue balance of $0.6 million and $1.6 million , as of December 31, 2015 and 2014 , respectively. The Company’s terms and conditions permit product returns and exchanges, and it records returns reserves in the period when revenue is recognized. Estimates are based on actual historical returns over the prior three years and are recorded as reductions in revenue at the time of sale. Upon recognition, the Company reduces revenue and cost of revenue for the estimated return. Return rates can fluctuate over time, but are sufficiently predictable to allow the Company to estimate expected future product returns. Cost of Revenue Cost of revenue includes direct and indirect costs associated with the manufacture of the Company’s products. Direct costs include material and labor, while indirect costs include inbound freight charges, receiving costs, inspection and testing costs, warehousing costs, royalty expense and other labor and overhead costs incurred in the manufacturing of products. Cost of revenue also includes stock-based compensation, warranty replacement costs, cost of revenue related to product return reserves and excess and obsolete inventory write-downs. Shipping Costs Shipping and handling costs charged to customers are recorded as revenue. Shipping and handling costs are included in cost of revenue. Research and Development (R&D) Costs R&D costs primarily consist of product development, clinical and regulatory expenses, materials, depreciation and other costs associated with the development of the Company’s products. R&D costs also include related personnel and consultants’ salaries, benefits and related costs, including stock-based compensation. The Company expenses R&D costs as they are incurred. The Company’s clinical trial accruals are based on estimates of patient enrollment and related costs at clinical investigator sites. The Company estimates preclinical and clinical trial expenses based on the services performed pursuant to contracts with research institutions and clinical research organizations that conduct and manage preclinical studies and clinical trials on its behalf. In accruing service fees, the Company estimates the time period over which services will be performed and the level of patient enrollment and activity expended in each period. If the actual timing of the performance of services or the level of effort varies from the estimate, the Company will adjust the accrual accordingly. Payments made to third parties under these arrangements in advance of the receipt of the related services are recorded as prepaid expenses until the services are rendered. Advertising Costs Advertising costs are included in sales, general and administrative expenses and are expensed as incurred. Advertising costs consist primarily of trade show and booth costs, product demonstration, and marketing materials. Advertising costs were $0.5 million , $0.3 million and $0.1 million for the years ended December 31, 2015 , 2014 and 2013 , respectively. Stock-Based Compensation The Company recognizes the cost of stock-based compensation in the financial statements based upon fair value. The fair value of restricted stock and restricted stock unit (RSU) awards is determined based on the number of units granted and the closing price of the Company’s common stock as of the grant date. The fair value of stock options is determined as of the grant date using the Black-Scholes option pricing model. The Company’s determination of the fair value of stock options is impacted by the price of the Company's common stock as well as changes in assumptions regarding a number of highly complex and subjective variables. These variables include, but are not limited to, the expected term that options will remain outstanding, expected common stock price volatility over the term of the option awards, risk-free interest rates and expected dividends. The fair value of an option award is recognized over the period during which an optionee is required to provide services in exchange for the option award, known as the requisite service period (usually the vesting period) on a straight-line basis. Stock-based compensation expense recognized at fair value includes the impact of estimated forfeitures. The Company estimates future forfeitures at the date of grant and revises the estimates, if necessary, in subsequent periods if actual forfeitures differ from those estimates. To the extent actual forfeiture results differ from the estimates, the difference is recorded as a cumulative adjustment in the period forfeiture estimates are revised. No compensation cost is recorded for options that do not vest. Equity instruments issued to non-employees are recorded at their fair value on the measurement date and are subject to periodic adjustments as the underlying equity instruments vest. The fair value of these equity instruments are expensed over the service period. Estimates of the fair value of equity-settled awards as of the grant date using valuation models, such as the Black-Scholes option pricing model, are affected by assumptions regarding a number of complex variables. Changes in the assumptions can materially affect the fair value of the award and ultimately how much stock-based compensation expense is recognized. These inputs are subjective and generally require significant analysis and judgment to develop. For all stock options granted to date, the Company estimated the volatility data based on a study of publicly traded industry peer companies. For purposes of identifying these peer companies, the Company considered the industry, stage of development, size and financial leverage of potential comparable companies. The risk-free interest rate is based on the yield available on U.S. Treasury zero-coupon issues similar in duration to the expected term of the equity-settled award. The Company uses the Staff Accounting Bulletin, No. 110 ( SAB 110) simplified method to calculate the expected term, which is the average of the contractual term and vesting period. Income Taxes The Company accounts for income taxes using the asset and liability method, whereby deferred tax asset and liability account balances are determined based on differences between the financial reporting and tax bases of assets and liabilities, and are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse. The Company provides a valuation allowance to reduce the net deferred tax assets to their estimated realizable value. The calculation of the Company’s current provision for income taxes involves the use of estimates, assumptions and judgments while taking into account current tax laws, interpretation of current tax laws and possible outcomes of future tax audits. The Company has established reserves to address potential exposures related to tax positions that could be challenged by tax authorities. Although the Company believes its estimates, assumptions and judgments to be reasonable, any changes in tax law or its interpretation of tax laws and the resolutions of potential tax audits could significantly impact the amounts provided for income taxes in the Company’s consolidated financial statements. The calculation of the Company’s deferred tax asset balance involves the use of estimates, assumptions and judgments while taking into account estimates of the amounts and type of future taxable income. Actual future operating results and the underlying amount and type of income could differ materially from the Company’s estimates, assumptions and judgments thereby impacting the Company’s financial position and results of operations. The Company follows the guidance relating to accounting for uncertainty in income taxes, which prescribes a recognition threshold and measurement attribute for the financial statement recognition and measurement of uncertain tax positions taken or expected to be taken in the Company’s income tax return, and also provides guidance on derecognition, classification, interest and penalties, accounting in interim periods and disclosure. The Company includes interest and penalties related to unrecognized tax benefits within income tax expense in the accompanying consolidated statements of operations. Comprehensive Income The Company is required to display comprehensive income and its components as part of the Company’s consolidated financial statements. Comprehensive income consists of net income, unrealized gains or losses on available-for-sale investments and the effects of foreign currency translation. Net Income (Loss) Per Share of Common Stock The Company, for the periods prior to the closing of the IPO, calculated its basic and diluted net income (loss) per share attributable to common stockholders in conformity with the two-class method required for companies with participating securities. Under the two-class method, the Company determined whether it had net income (loss) attributable to common stockholders, which included the results of operations less current period preferred stock non-cumulative dividends. If it was determined that the Company did have net income (loss) attributable to common stockholders during a period, the related undistributed earnings were then allocated between common stock and the preferred stock based on the weighted average number of shares outstanding during the period to determine the numerator for the basic net income (loss) per share attributable to common stockholders. In computing diluted net income attributable to common stockholders, undistributed earnings were re-allocated to reflect the potential impact of dilutive securities to determine the numerator for the diluted net income per share attributable to common stockholders. The Company’s basic net income (loss) per share attributable to common stockholders is calculated by dividing the net income (loss) by the weighted average number of shares of common stock outstanding for the period. The diluted net income per share attributable to common stockholders is computed by giving effect to all potential dilutive common stock equivalents outstanding for the period. For purposes of this calculation, options to purchase common stock, restricted stock, RSUs and common stock warrants are considered common stock equivalents. Recently Issued Accounting Standards In May 2014, the Financial Accounting Standards Board (FASB) issued ASU No. 2014-09, Revenue from Contracts with Customers , which outlines a comprehensive new revenue recognition model designed to depict the transfer of promised 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. In August 2015, the FASB issued ASU No. 2015-14, Revenue from Contracts with Customers — Deferral of the Effective Date to defer the effective date by one year for annual reporting periods beginning after December 15, 2017, including interim reporting periods within that reporting period. Earlier adoption is permitted only as of annual reporting periods beginning after December 15, 2016, including interim reporting periods within that reporting period. The Company is currently evaluating the impact of this accounting standard. In July 2015, the FASB issued ASU No. 2015-11, Simplifying the Measurement of Inventory , which requires an entity to measure most inventory at the lower of cost and net realizable value, thereby simplifying the current guidance under which an entity must measure inventory at the lower of cost or market. The accounting standard is effective prospectively for annual periods beginning after December 15, 2016, and interim periods therein. Early adoption is permitted as of the beginning of an interim or annual reporting period. The Company is currently evaluating the impact of this accounting standard. In November 2015, the FASB issued ASU No. 2015-17, Balance Sheet Classification of Deferred Taxes , which requires that deferred tax assets and liabilities be classified as non-current in a classified statement of financial position. The accounting standard is effective, either prospectively to all deferred tax assets and liabilities or retrospectively to all periods presented, for annual periods beginning after December 15, 2016, and interim periods therein. Early adoption is permitted as of the beginning of an interim or annual reporting period. The Company early adopted this standard as of December 31, 2015 on a prospective basis. In January 2016, the FASB issued ASU 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities , which addresses certain aspects of recognition, measurement, presentation and disclosure of financial instruments . The new standard is effective for annual periods and interim periods beginning after December 15, 2017, and upon adoption, an entity should apply the amendments by means of a cumulative-effect adjustment to the balance sheet at the beginning of the first reporting period in which the guidance is effective. Early adoption is not permitted except for the provision to record fair value changes for financial liabilities under the fair value option resulting from instrument-specific credit risk in other comprehensive income. The Company is currently evaluating the impact of adopting this guidance. In February 2016, the FASB issued ASU 2016-02, Leases , which requires to recognize and measure leases at the beginning of the earliest period presented using a modified retrospective approach. The accounting standard is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early adoption is permitted. The Company is currently evaluating the impact of adopting this guidance.

Initial Public Offering (IPO)

Initial Public Offering (IPO)	12 Months Ended
	Dec. 31, 2015
Equity [Abstract]
Initial Public Offering, Common Stock, Warrants, and Common and Preferred Stock Repurchase	Initial Public Offering (IPO) The Company closed its IPO on September 23, 2015, in which it sold 4.6 million shares of common stock at an offering price of $30.00 per share and raised $124.7 million in net proceeds after deducting underwriting discounts and commissions of $9.7 million and other offering expenses of $3.6 million . Upon the closing of the IPO, all outstanding shares of convertible preferred stock of the Company were automatically converted into 19,510,410 shares of common stock on a one -for-one basis. Common Stock Each share of common stock is entitled to one vote. The holders of common stock are also entitled to receive dividends whenever funds are legally available and when declared by the board of directors, subject to the prior rights of holders of all classes of stock outstanding. Warrants In connection with the sale of Series B preferred stock in 2004, the Company issued warrants to purchase 211,138 shares of common stock at a purchase price of $0.01 per share. The warrants were exercisable upon grant and had a term of 10 years from the date of grant, which expired on December 31, 2014 . The value of the warrants was calculated using Black-Scholes option pricing model and was deemed to be immaterial. No warrants were outstanding as of December 31, 2015 or 2014 . Common and Preferred Stock Repurchase The Company’s board of directors approved the repurchase of 70,612 shares of common stock, 45,000 stock options and 45,611 of preferred stock from shareholders in May 2014 for $13.20 per share for a total purchase price of $2.0 million . For the repurchased shares of common stock and stock options, the Company charged the difference between the purchase and market prices of $0.5 million to expense. For the repurchased preferred shares, the excess between the purchase and the issuance price of $0.5 million was treated as a deemed dividend. In addition, the Company closed a tender offer in July 2014 to repurchase shares of preferred stock from existing shareholders at a purchase price of $13.20 per share. The Company repurchased 584,052 shares of preferred stock for a total purchase price of $7.7 million . The excess between the purchase and the issuance price of $5.8 million was treated as a deemed dividend. The repurchased shares of common and preferred stock were retired and remained as authorized but unissued.

Fair Value of Financial Instrum

Fair Value of Financial Instruments	12 Months Ended
	Dec. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	Fair Value of Financial Instruments Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the reporting date. The accounting guidance establishes a three-tiered hierarchy, which prioritizes the inputs used in the valuation methodologies in measuring fair value: Level 1 - Quoted prices in active markets for identical assets or liabilities. Level 2 - Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 - Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The categorization of a financial instrument within the valuation hierarchy is based on the lowest level of input that is significant to the fair value measurement. The Company classifies its cash equivalents and marketable investments within Level 1 and Level 2, as it uses quoted market prices or alternative pricing sources and models utilizing market observable inputs. The Company determined the fair value of its Level 1 financial instruments, which are traded in active markets, using quoted market prices for identical instruments. Marketable investments classified within Level 2 of the fair value hierarchy are valued based on other observable inputs, including broker or dealer quotations or alternative pricing sources. When quoted prices in active markets for identical assets or liabilities are not available, the Company relies on non-binding quotes from its investment managers, which are based on proprietary valuation models of independent pricing services. These models generally use inputs such as observable market data, quoted market prices for similar instruments, historical pricing trends of a security as relative to its peers and internal assumptions of the independent pricing services. To validate the fair value determination provided by its investment managers, the Company reviews the pricing movement in the context of overall market trends and trading information from its investment managers. In addition, the Company assesses the inputs and methods used in determining the fair value in order to determine the classification of securities in the fair value hierarchy. The Company did not own any Level 3 financial assets or liabilities as of December 31, 2015 or 2014 . The Company did not have any financial assets and liabilities measured at fair value on a non-recurring basis as of December 31, 2015 and 2014 . During the years ended December 31, 2015 , 2014 and 2013 , the Company did not record any impairment charges related to its marketable investments, and the Company did not have any transfers between Level 1, Level 2 and Level 3 of the fair value hierarchy. The following tables set forth the Company’s financial assets and liabilities measured at fair value by level within the fair value hierarchy (in thousands): As of December 31, 2015 Level 1 Level 2 Level 3 Fair Value Financial Assets Cash equivalents: Commercial paper $ — $ 9,850 $ — $ 9,850 Money market funds 252 — — 252 Marketable investments: Commercial paper — 22,332 — 22,332 U.S. Treasury 15,436 — — 15,436 U.S. Agency securities — 21,464 — 21,464 U.S. States and Municipalities — 2,084 — 2,084 Corporate bonds — 61,002 — 61,002 Non-U.S. Government debt securities — 6,939 — 6,939 Total $ 15,688 $ 123,671 $ — $ 139,359 As of December 31, 2014 Level 1 Level 2 Level 3 Fair Value Financial Assets Cash equivalents: Money market funds $ 155 $ — $ — $ 155 Marketable investments: Mutual funds 8,619 — — 8,619 U.S. Treasury 4,009 — — 4,009 U.S. Agency securities — 6,006 — 6,006 Corporate bonds — 29,619 — 29,619 Total $ 12,783 $ 35,625 $ — $ 48,408

Balance Sheet Components

Balance Sheet Components	12 Months Ended
	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Balance Sheet Components	Balance Sheet Components Accounts Receivable, Net The Company’s allowance for doubtful accounts comprised of the following (in thousands): Balance At Charged To Deductions Balance At For the year ended: December 31, 2013 $ 212 $ 259 $ — $ 471 December 31, 2014 471 150 (19 ) 602 December 31, 2015 602 (13 ) — 589 Prepaid Expenses and Other Current Assets The Company’s prepaid expenses and other current assets comprised of the following (in thousands): December 31, 2015 2014 Prepaid expenses $ 7,442 $ 3,130 Income tax receivable 606 1,654 Other current assets 1,304 331 Prepaid expenses and other current assets $ 9,352 $ 5,115 Marketable Investments The Company’s marketable investments as of December 31, 2015 and 2014 were as follows (in thousands): December 31, 2015 Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Commercial paper $ 22,328 $ 5 $ (1 ) $ 22,332 U.S. Treasury 15,459 4 (27 ) 15,436 U.S. Agency securities 21,497 1 (34 ) 21,464 U.S. States and Municipalities 2,086 — (2 ) 2,084 Corporate bonds 61,188 3 (189 ) 61,002 Non-U.S. Government debt securities 6,954 1 (16 ) 6,939 Total $ 129,512 $ 14 $ (269 ) $ 129,257 December 31, 2014 Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value U.S. Agency securities $ 6,012 $ 3 $ (9 ) $ 6,006 U.S. Treasury 4,011 — (2 ) 4,009 Corporate bonds 29,834 4 (219 ) 29,619 Mutual funds 8,768 — (149 ) 8,619 Total $ 48,625 $ 7 $ (379 ) $ 48,253 The following tables present the gross unrealized losses and the fair value for those marketable investments that were in an unrealized loss position for less than twelve months as of December 31, 2015 and 2014 (in thousands): December 31, 2015 Fair Value Gross Unrealized Losses Commercial paper $ 4,746 $ (1 ) US Treasury 12,453 (27 ) US Agency securities 13,475 (34 ) US States and Municipalities 2,084 (2 ) Corporate bonds 59,163 (189 ) Non-U.S. government debt securities 5,881 (16 ) Total $ 97,802 $ (269 ) December 31, 2014 Fair Value Gross Unrealized Losses Mutual Funds $ 8,619 $ (149 ) US Treasury 3,008 (2 ) US Agency Securities 5,255 (9 ) Corporate Bonds 26,633 (219 ) Total $ 43,515 $ (379 ) As of December 31, 2015 and 2014 , there were no securities that had been in a loss position for more than twelve months. The contractual maturities of the Company’s marketable investments as of December 31, 2015 and 2014 were as follows (in thousands): December 31, 2015 2014 Marketable Investments Fair Value Fair Value Due in one year $ 62,983 $ 16,442 Due in one to five years 66,274 31,811 Total $ 129,257 $ 48,253 Inventories The components of inventories consisted of the following (in thousands): December 31, 2015 2014 Raw materials $ 9,176 $ 5,105 Work in process 2,746 543 Finished goods 44,839 27,803 Inventories $ 56,761 $ 33,451 Property and Equipment, Net Property and equipment, net consisted of the following (in thousands): December 31, 2015 2014 Machinery and equipment $ 8,559 $ 5,089 Furniture and fixtures 2,091 519 Leasehold improvements 1,564 379 Software 666 599 Computers 565 153 Construction in progress 577 1,931 Total property and equipment 14,022 8,670 Less: Accumulated depreciation and amortization (5,071 ) (3,489 ) Property and equipment, net $ 8,951 $ 5,181 Depreciation and amortization expense was $1.8 million , $0.8 million and $0.7 million for the years ended December 31, 2015 , 2014 and 2013 , respectively. Accrued Liabilities The following table shows the components of accrued liabilities (in thousands): December 31, 2015 2014 Payroll and employee-related expenses $ 13,653 $ 8,221 Sales return reserve 3,247 2,164 Preclinical and clinical trial cost 1,330 2,319 Deferred revenue 526 1,591 Product warranty 713 314 Sales tax payable 531 306 Income tax payable 308 332 Other accrued liabilities 5,273 3,228 Total accrued liabilities $ 25,581 $ 18,475 The estimated product warranty accrual was as follows (in thousands): December 31, 2015 2014 2013 Balance at the beginning of the year $ 314 $ 323 $ 323 Accruals of warranties issued 752 149 100 Settlements of warranty claims (353 ) (158 ) (100 ) Balance at the end of the year $ 713 $ 314 $ 323

Credit Facility

Credit Facility	12 Months Ended
	Dec. 31, 2015
Debt Disclosure [Abstract]
Credit Facility	Credit Facility In May 2012, the Company entered into a revolving credit facility of $15.0 million with Wells Fargo Bank, National Association. The credit facility was collateralized by the Company’s investment balances. The interest on the credit facility was based on the daily one-month London Inter-Bank Offered Rate, plus 1.75% and was payable monthly. The credit facility contained customary covenants for credit facilities of this type, including limitations on disposition of assets and changes in control. In May 2014, in conjunction with its Series F preferred stock financing, the Company paid the then outstanding balance on the credit facility and terminated the credit facility.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2015
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions Notes Receivable from Stockholders In March 2005, options to purchase 250,000 shares of common stock, subject to repurchase by the Company, were exercised in exchange for a full recourse promissory note totaling $21,250 . The note bore interest at 2.92% per year, compounded annually. The Company received the amount due including interest under the promissory note in the fourth quarter of 2015 . In July 2011, options to purchase 5,000 shares of common stock were exercised in exchange for a full recourse promissory note totaling $4,600 . The note is noninterest bearing and is due in full on December 31, 2016. As of December 31, 2015 and 2014 , the amounts due under outstanding promissory notes were $4,600 and $0.1 million , respectively.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Lease Commitments The Company leases its offices and other equipment under non-cancelable operating leases that expire at various dates from 2029 to 2031 . In December 2015, the Company entered into a lease agreement (the Lease) relating to the lease of additional office, research and development and manufacturing space at the campus where the Company’s headquarters is located in Alameda, California. Pursuant to the Lease, the Company agreed to lease 99,968 square feet of space (plus an additional space of 15,882 square feet that may be delivered to the Company at the landlord’s option prior to May 1, 2016 ). From time to time during the ten year period following the initial commencement date of the new lease, if any space in any of the buildings located in the same business park as our campus becomes vacant, that space will be added to the lease at the then current base monthly rental rate. The maximum additional space that could be added under this provision of the lease is 117,325 square feet. The Company has a right of first offer to lease any space that becomes available after the expiration of the ten year period following the initial commencement date, subject to the terms described in the new lease. The term of the lease expires after 15 years from the initial lease commencement date, subject to the Company’s option to renew the lease for up to three additional five -year periods. The table below does not include the Company ’s potential obligation for the additional space(s) that may be added to the lease by the landlord. Rent expense for the years ended December 31, 2015 , 2014 , and 2013 was $3.2 million , $1.8 million and $1.7 million , respectively. Future minimum lease payments under the non-cancelable operating leases as of December 31, 2015 are as follows (in thousands): Lease Payments Year Ending December 31: 2016 $ 4,055 2017 4,861 2018 4,877 2019 5,007 2020 5,133 Thereafter 52,555 Total future minimum lease payments $ 76,488 Purchase Commitments The Company had non-cancellable purchase obligations to suppliers at December 31, 2015 of $11.8 million . Royalty Obligations In March 2005, the Company entered into a license agreement that requires the Company to make minimum royalty payments to the licensor, on a quarterly basis. As of December 31, 2015 and 2014 , the license agreement requires minimum annual royalty payments of $0.1 million and $0.1 million in equal quarterly installments, respectively. On each January 1, the quarterly calendar year minimum royalty shall be adjusted to equal the prior year’s minimum royalty adjusted by a percentage equal to the percentage change in the “consumer price index for all urban consumers” for the prior calendar year as reported by the U.S. Department of Labor. Unless terminated earlier, the term of the license agreement shall continue until the expiration of the last to expire patent that covers that licensed product or for the period of 15 years following the first commercial sale of such licensed product, whichever is longer. The first commercial sale of covered products occurred in June 2007. In April 2012, the Company entered into an agreement that requires the Company to pay a 5% royalty on sales of products covered under applicable patents, on a quarterly basis. The first commercial sale of covered products occurred in April 2014. Unless terminated earlier, the royalty term for each applicable product shall continue for 15 years following the first commercial sale of such patented product, or when the applicable patent covering such product has expired, whichever is sooner. In April 2015, the Company entered into a royalty agreement that requires the Company to pay a 2% royalty on sales of certain products covered by the agreement, on a quarterly basis. The Company began the first commercial sale of the covered products in July 2015. Unless terminated earlier, the royalty term for each covered product shall continue for 20 years following the first commercial sale of the covered products. Royalty expense included in cost of sales for the years ended December 31, 2015 , 2014 and 2013 was $2.0 million , $1.1 million and $0.7 million , respectively. Contingencies From time to time, the Company may have certain contingent liabilities that arise in the ordinary course of business. The Company accrues a liability for such matters when it is probable that future expenditures will be made and such expenditures can be reasonably estimated. Indemnification The Company enters into standard indemnification arrangements in the ordinary course of business. Pursuant to these arrangements, the Company indemnifies, holds harmless, and agrees to reimburse the indemnified parties for losses suffered or incurred by the indemnified party, in connection with any trade secret, copyright, patent or other intellectual property infringement claim by any third-party with respect to the Company’s technology. The term of these indemnification agreements is generally perpetual. The maximum potential amount of future payments the Company could be required to make under these agreements is not determinable because it involves claims that may be made against the Company in the future, but have not yet been made. The Company has entered into indemnification agreements with its directors and officers that may require the Company to indemnify its directors and officers against liabilities that may arise by reason of their status or service as directors or officers, other than liabilities arising from willful misconduct of the individual. The Company has not incurred costs to defend lawsuits or settle claims related to these indemnification agreements. No liability associated with such indemnifications has been recorded to date. Litigation The Company was contacted in 2015 by the attorney for a potential product liability claimant who allegedly suffered injuries as a result of aneurysm procedure in which the Penumbra Coil 400 was used. On February 19, 2016, a complaint for damages was filed on behalf of this claimant against Penumbra and the hospital involved in the procedure ( Montgomery v. Penumbra, Inc., et al., Case No. 16-2-04050-1 SEA, Superior Court of the State of Washington, King County) . The suit alleges liability primarily under the Washington Product Liability Act and seeks both compensatory and punitive damages without a specific damages claim. Counsel for the claimant previously indicated that he expects that a jury could award $35 million in damages were this matter to go to trial. This amount is substantially in excess of the Company’s insurance coverage. The hospital defendant has requested indemnification from Penumbra. As the litigation has been filed recently and the parties have not engaged in formal discovery, the Company is unable to assess the merits of the plaintiff’s case. The Company intends to vigorously defend the litigation, as the Company believes there will be substantial questions regarding causation, liability and damages. From time to time, the Company is subject to claims and assessments in the ordinary course of business. The Company is not currently a party to any litigation matter that, individually or in the aggregate, is expected to have a material adverse effect on the Company’s business, financial condition, results of operations or cash flows.

Convertible Preferred Stock

Convertible Preferred Stock	12 Months Ended
	Dec. 31, 2015
Temporary Equity Disclosure [Abstract]
Convertible Preferred Stock	Convertible Preferred Stock The convertible preferred stock at December 31, 2014 consisted of the following (in thousands, except shares): Series Shares Authorized Shares Issued and Outstanding Proceeds, Net of Issuance Costs Aggregate Liquidation Amount Series A Preferred Stock 1,000,000 1,000,000 $ 299 $ 554 Series B Preferred Stock 4,287,486 4,005,338 6,536 11,725 Series C Preferred Stock 4,388,715 4,168,218 13,266 22,238 Series D Preferred Stock 3,944,733 3,881,459 19,647 30,976 Series E Preferred Stock 1,973,684 1,909,940 14,507 21,609 Series F Preferred Stock 5,303,031 4,545,455 57,212 62,259 Undesignated 4,102,351 — — — Total convertible preferred stock 25,000,000 19,510,410 $ 111,467 $ 149,361 Upon the closing of the IPO on September 23, 2015, all outstanding shares of convertible preferred stock were automatically converted into 19,510,410 shares of common stock on a one -for-one basis and the related balance was reclassified from temporary equity to common stock and additional paid-in capital.

Common Stock

Common Stock	12 Months Ended
	Dec. 31, 2015
Equity [Abstract]
Initial Public Offering, Common Stock, Warrants, and Common and Preferred Stock Repurchase	Initial Public Offering (IPO) The Company closed its IPO on September 23, 2015, in which it sold 4.6 million shares of common stock at an offering price of $30.00 per share and raised $124.7 million in net proceeds after deducting underwriting discounts and commissions of $9.7 million and other offering expenses of $3.6 million . Upon the closing of the IPO, all outstanding shares of convertible preferred stock of the Company were automatically converted into 19,510,410 shares of common stock on a one -for-one basis. Common Stock Each share of common stock is entitled to one vote. The holders of common stock are also entitled to receive dividends whenever funds are legally available and when declared by the board of directors, subject to the prior rights of holders of all classes of stock outstanding. Warrants In connection with the sale of Series B preferred stock in 2004, the Company issued warrants to purchase 211,138 shares of common stock at a purchase price of $0.01 per share. The warrants were exercisable upon grant and had a term of 10 years from the date of grant, which expired on December 31, 2014 . The value of the warrants was calculated using Black-Scholes option pricing model and was deemed to be immaterial. No warrants were outstanding as of December 31, 2015 or 2014 . Common and Preferred Stock Repurchase The Company’s board of directors approved the repurchase of 70,612 shares of common stock, 45,000 stock options and 45,611 of preferred stock from shareholders in May 2014 for $13.20 per share for a total purchase price of $2.0 million . For the repurchased shares of common stock and stock options, the Company charged the difference between the purchase and market prices of $0.5 million to expense. For the repurchased preferred shares, the excess between the purchase and the issuance price of $0.5 million was treated as a deemed dividend. In addition, the Company closed a tender offer in July 2014 to repurchase shares of preferred stock from existing shareholders at a purchase price of $13.20 per share. The Company repurchased 584,052 shares of preferred stock for a total purchase price of $7.7 million . The excess between the purchase and the issuance price of $5.8 million was treated as a deemed dividend. The repurchased shares of common and preferred stock were retired and remained as authorized but unissued.

Warrants

Warrants	12 Months Ended
	Dec. 31, 2015
Equity [Abstract]
Initial Public Offering, Common Stock, Warrants, and Common and Preferred Stock Repurchase	Initial Public Offering (IPO) The Company closed its IPO on September 23, 2015, in which it sold 4.6 million shares of common stock at an offering price of $30.00 per share and raised $124.7 million in net proceeds after deducting underwriting discounts and commissions of $9.7 million and other offering expenses of $3.6 million . Upon the closing of the IPO, all outstanding shares of convertible preferred stock of the Company were automatically converted into 19,510,410 shares of common stock on a one -for-one basis. Common Stock Each share of common stock is entitled to one vote. The holders of common stock are also entitled to receive dividends whenever funds are legally available and when declared by the board of directors, subject to the prior rights of holders of all classes of stock outstanding. Warrants In connection with the sale of Series B preferred stock in 2004, the Company issued warrants to purchase 211,138 shares of common stock at a purchase price of $0.01 per share. The warrants were exercisable upon grant and had a term of 10 years from the date of grant, which expired on December 31, 2014 . The value of the warrants was calculated using Black-Scholes option pricing model and was deemed to be immaterial. No warrants were outstanding as of December 31, 2015 or 2014 . Common and Preferred Stock Repurchase The Company’s board of directors approved the repurchase of 70,612 shares of common stock, 45,000 stock options and 45,611 of preferred stock from shareholders in May 2014 for $13.20 per share for a total purchase price of $2.0 million . For the repurchased shares of common stock and stock options, the Company charged the difference between the purchase and market prices of $0.5 million to expense. For the repurchased preferred shares, the excess between the purchase and the issuance price of $0.5 million was treated as a deemed dividend. In addition, the Company closed a tender offer in July 2014 to repurchase shares of preferred stock from existing shareholders at a purchase price of $13.20 per share. The Company repurchased 584,052 shares of preferred stock for a total purchase price of $7.7 million . The excess between the purchase and the issuance price of $5.8 million was treated as a deemed dividend. The repurchased shares of common and preferred stock were retired and remained as authorized but unissued.

Stock Option Plans

Stock Option Plans	12 Months Ended
	Dec. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Option Plans	Stock Option Plans 2005 Stock Plan The Company adopted the Penumbra, Inc. 2005 Stock Plan (the 2005 Plan) in January 2005. The 2005 Plan was subsequently amended and restated in 2006, 2007, 2008 and 2010. As of December 31, 2015 and 2014 , the Company had granted options to purchase 5,431,017 and 5,431,017 shares of common stock, respectively, under the 2005 Plan, of which options to purchase 1,757,282 and 2,707,176 shares of common stock were outstanding, and options to purchase 12,339 and 33,081 shares of common stock had been early exercised and were unvested and subject to repurchase, as of December 31, 2015 and 2014 , respectively. Under the 2005 Plan, the board of directors could grant incentive stock options (ISO s ), nonqualified stock options (NSOs), and/or stock awards to eligible persons, including employees, nonemployees, directors, consultants and other independent advisors who provide services to the Company. Stock purchase rights could also be granted under the 2005 Plan. The board of directors had the authority to determine to whom options would be granted, the number of options, the term and the exercise price. ISOs could only be granted to Company employees, which include officers and directors of the Company. NSOs and stock purchase rights could be granted to employees and consultants. For individuals holding more than 10% of the voting rights of all classes of stock, the exercise price for an ISO could not be less than 110% of fair market value. Options granted under the 2005 Plan permitted an optionee to exercise options immediately upon grant irrespective of the vesting term. Options generally vest annually at a rate of 1/4 after the first year and 1/48 per month thereafter. The term of the options is no longer than five years for ISOs, for which the grantee owns greater than 10% of the voting power of all classes of stock and no longer than 10 years for all other options. 2011 Equity Incentive Plan The Company adopted the Penumbra, Inc. 2011 Equity Incentive Plan (the 2011 Plan) in October 2011. As of December 31, 2015 and 2014 , the Company had granted options to purchase 145,000 and 145,000 shares of common stock, respectively, under the 2011 Plan, of which options to purchase 145,000 and 145,000 shares of common stock were outstanding at December 31, 2015 and 2014 , respectively. As of December 31, 2015 and 2014 , the Company had granted 505,000 and 505,000 shares of restricted stock under the 2011 Plan, of which 249,125 and 367,126 shares were unvested and subject to forfeiture and 4,667 and 1,667 shares had been forfeited as of December 31, 2015 and 2014 , respectively. Under the 2011 Plan, the board of directors could grant ISOs, NSOs, restricted stock, and/or RSUs to eligible persons, including employees, directors and consultants who provide services to the Company. Stock Appreciation Rights (SAR) could also be granted under the 2011 Plan. The board of directors had the authority to determine to whom options would be granted, the number of options, the term and the exercise price. ISOs could only be granted to Company employees, which include officers and directors of the Company. NSOs, SARs, restricted stock and RSUs could be granted to employees and consultants. For individuals holding more than 10% of the voting rights of all classes of stock, the exercise price for an ISO could not be less than 110% of fair market value. Stock options granted under the 2011 Plan generally have a contractual life of ten years, and generally vest over a period of four years. Amended and Restated 2014 Equity Incentive Plan The Company adopted the Penumbra, Inc. 2014 Equity Incentive Plan in May 2014. The plan was amended and restated as of September 17, 2015 (as amended and restated, the 2014 Plan). The 2014 Plan replaced the 2011 Plan and the 2005 Plan and no further equity awards may be granted under the 2011 Plan or the 2005 Plan. Under the 2014 Plan, 3,000,000 shares of common stock were reserved for issuance, of which as of December 31, 2015 , 597,730 shares of common stock were available for grant. As of December 31, 2015 and 2014 , the Company had granted options to purchase 1,857,900 and 48,500 shares of common stock under the 2014 Plan, 1,853,063 and 48,500 of which were outstanding and 4,421 and 1,000 of which had been forfeited as of December 31, 2015 and 2014 , respectively. The Company had granted 673,361 and 0 shares of restricted stock under the 2014 Plan, as of December 31, 2015 and 2014 , respectively, of which 508,646 and 0 shares were unvested and subject to forfeiture as of such dates. The Company had granted 91,800 and 0 shares of RSU under the 2014 Plan, as of December 31, 2015 and 2014 , respectively, of which 91,800 and 0 shares were unvested and subject to forfeiture as of such dates. Employee Stock Purchase Plan The Penumbra, Inc. Employee Stock Purchase Plan (the ESPP ) , became effective on September 17, 2015. The ESPP initially reserved 600,000 shares of common stock for purchase under the ESPP, with the number of shares reserved for purchase automatically increasing each year pursuant to an “evergreen” provision set forth in the ESPP. All qualifying employees of the Company and its designated subsidiaries are eligible to participate in the ESPP. Each offering to the Company’s employees to purchase stock under the ESPP will begin on each May 20 and November 20 and will end on the following November 19 and May 19, respectively, each referred to as offering periods, except that the first offering period under the ESPP began on September 17, 2015 and will end on May 19, 2016. Under the ESPP, each employee may purchase shares by authorizing payroll deductions at a minimum of 1% and up to 15% of his or her eligible compensation for each pay period during the offering period. Unless the participating employee withdraws from the offering, his or her accumulated payroll deductions will be used to purchase the Company’s common stock on the last business day of the offering period at a price equal to 85% of the fair market value of the common stock on either the first or the last day of the offering period, whichever is lower, provided that no more than 2,000 shares of the Company’s common stock or such other lesser maximum number established by the ESPP administrator may be purchased by any one employee during each offering period. Under applicable tax rules, an employee may purchase no more than $25,000 worth of common stock, valued at the start of the purchase period (corresponding to an offering period), under the ESPP in any calendar year. Early Exercises Stock options granted under the 2005 Plan, 2011 Plan and 2014 Plan allow the board of directors to grant awards to provide employee option holders the right to elect to exercise unvested options in exchange for restricted common stock. Unvested shares, which amounted to 12,339 and 33,081 as of December 31, 2015 and 2014 , respectively, were subject to a repurchase right held by the Company at the original issue price in the event the optionees’ employment was terminated either voluntarily or involuntarily. For exercises of employee options, this right lapses according to the vesting schedule designated on the associated option grant. The repurchase terms are considered to be a forfeiture provision. The shares purchased by the employees pursuant to the early exercise of stock options are not deemed to be issued or outstanding for accounting purposes until those shares vest, though they are legally issued and outstanding. In addition, cash received from employees for exercise of unvested options is treated as a refundable deposit shown as a liability on the consolidated balance sheets. As of December 31, 2015 and 2014 , cash received related to unvested shares totaled $0.1 million and $0.2 million , respectively. Amounts recorded are transferred into common stock and additional paid-in-capital as the shares vest. Activity of stock options under 2005 Plan, 2011 Plan and 2014 Plan is set forth below: Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Life (in Years) Aggregate Intrinsic Value (in thousands) Balance, December 31, 2014 2,900,676 $ 2.66 Granted 1,809,400 21.47 Exercised (948,872 ) 0.99 Canceled/Forfeited (5,859 ) 11.15 Balance, December 31, 2015 3,755,345 $ 12.13 Vested and expected to vest—December 31, 2015 3,621,919 $ 11.79 6.70 $ 152,187 Exercisable—December 31, 2015 1,941,150 $ 3.47 4.20 $ 97,717 The Company uses the Black-Scholes option pricing model to determine the fair value of stock options. The valuation model for stock compensation expense requires the Company to make assumptions and judgments about the variables used in the calculation including the expected term (weighted average period of time that the options granted are expected to be outstanding); volatility of the Company’s common stock and an assumed-risk-free interest rate. The Company used the following assumptions in its Black-Scholes option pricing model to determine the fair value of stock options: Year Ended December 31, 2015 2014 2013 Expected term (in years) 6.08—6.25 6.25 6.25 Expected volatility 45% 45% 45% Risk-free interest rate 1.56%—1.78% 1.76%—2.02% 0.63%—0.90% Expected dividend rate 0% 0% 0% Fair Value of Common Stock. Prior to the IPO, the fair value of the shares of common stock underlying the Company's stock options was determined by the Company’s board of directors. Because there was no public market for the Company’s common stock and in the absence of recent arm’s-length cash sales transactions of the Company’s common stock with independent third parties, the Company’s board of directors determined the fair value of the Company’s common stock by considering at the time of grant a number of objective and subjective factors. The intent of the Company’s board of directors was for all options granted to be exercisable at a price per share not less than the per share fair value of the Company’s common stock underlying those options on the date of grant. The estimated fair value of the Company’s common stock was determined at each valuation date in accordance with the guidelines outlined in the American Institute of Certified Public Accountants Practice Aid, Valuation of Privately-Held-Company Equity Securities Issued as Compensation. The Company’s board of directors, with the assistance of management, developed these valuations using significant judgement and taking into account numerous factors, including the following: • independent third-party valuations; • progress of research and development activities; • the Company’s operating and financial performance, including its levels of available capital resources; • rights and preferences of the Company’s common stock compared to the rights and preferences of the Company’s other outstanding equity securities; • equity market conditions affecting comparable public companies, as reflected in comparable companies’ market multiples, IPO valuations and other metrics; • the achievement of enterprise milestones, including the Company’s progress in clinical trials; • the likelihood of achieving a liquidity event for the shares of common stock, such as an IPO given prevailing market and medical device sector conditions; • sales of the Company’s preferred stock in arms-length transactions; • the illiquidity of the Company’s securities by virtue of being a private company; • business risks; and • management and board experience. The Company considered the following approaches in the preparation of its valuations: • Market Approach. The market approach values a business by reference to guideline companies, for which enterprise values are known. This approach has two principal methodologies. The guideline public company methodology derives valuation multiples from the operating data and share prices of similar publicly traded companies. The guideline acquisition methodology focuses on comparisons between the subject company and guideline acquired public or private companies. • Option-Pricing Method Backsolve (OPM backsolve). The OPM backsolve method derives the implied equity value for a company from a recent transaction involving the Company’s own securities issued on an arms-length basis. • Probability Weighted Expected Return Method (PWERM) . Using the PWERM method, the value of a company’s common stock is estimated based upon the analysis of future values for the company assuming various possible future liquidity events like an initial public offering, sale or merger. Share value is based upon the probability-weighted present value of expected future net cash flows, considering each of the possible future events, as well as the rights and preferences of each share class. In addition, the Company also considered an enterprise value allocation method: • Option-Pricing Method (OPM) . Under the OPM method, each class of stock is modeled as a call option with a distinct claim on the enterprise value of the company. The option’s exercise prices would be based on a comparison with the enterprise value. The method assumes that a formula, such as the Black-Scholes model, would calculate the fair value when provided with certain values, including share price, expiration date, volatility and the risk free interest rate. The per share common stock value was estimated by allocating the Company’s enterprise value using the OPM method on October 1, 2013, May 16, 2014, and September 30, 2014, which determined the common value to be $ 7.75 , $ 9.06 and $ 10.92 , respectively. The per share common stock value was estimated in December 31, 2014, March 31, 2015, June 30, 2015 and July 31, 2015, which utilized the PWERM method, which determined the common stock value to be $ 12.36 , $ 14.46 , $ 20.51 and $ 22.04 , respectively. In determining the estimated fair value of the common stock, the Company’s board of directors also considered the fact that the Company’s stockholders could not freely trade the Company’s common stock in the public markets. Accordingly, the Company applied discounts to reflect the lack of marketability of its common stock based on the expected time to liquidity. The estimated fair value of the Company’s common stock at each grant date reflected a non-marketability discount partially based on the anticipated likelihood and timing of a future liquidity event. The key subjective factors and assumptions used in the Company’s valuations primarily consisted of: (i) the selection of the appropriate market comparable transactions, (ii) the selection of the appropriate comparable publicly traded companies, (iii) the financial forecasts utilized to determine future cash balances and necessary capital requirements, (iv) the probability and timing of the various possible liquidity events, (v) the estimated weighted-average cost of capital and (vi) the discount for lack of marketability of the Company’s common stock. At each grant date the board of directors reviewed any recent events and their potential impact on the estimated fair value per share of the common stock. Weighted Average Expected Term. The Company derived the expected term using the “simplified” method (the expected term is determined as the average of the time-to-vesting and the contractual life of the options), as the Company had limited historical information to develop expectations about future exercise patterns and post vesting employment termination behavior. Volatility. Since there has been no public market for the Company’s common stock and lack of company-specific historical volatility, it has determined the share price volatility for options granted based on an analysis of the volatility used by a peer group of publicly traded medical device companies. In evaluating similarity, the Company considers factors such as industry, stage of life cycle and size. Risk-Free Interest Rate. The risk-free interest rate is based upon U.S. Treasury zero-coupon issues with remaining terms similar to the expected term of the options. Dividend Yield. The Company has never paid any dividends and does not plan to pay dividends in the foreseeable future, and therefore, used an expected dividend yield of zero in the valuation model. Forfeitures. The Company is required to estimate forfeitures at the time of grant, and revise those estimates in subsequent periods if actual forfeitures differ from those estimates. The Company uses historical data to estimate pre-vesting option forfeitures and record stock based compensation expense only for those awards that are expected to vest. To the extent actual forfeitures differ from the estimates, the difference will be recorded as a cumulative adjustment in the period that the estimates are revised. The total intrinsic value of stock options exercised during the year ended December 31, 2015 , 2014 and 2013 was $13.1 million , $3.8 million and $0.3 million , respectively. The intrinsic value is calculated as the difference between the estimated fair value of the Company’s common stock at the exercise date and the exercise price of the stock option. The weighted average grant date fair value of the employee stock options was $9.69 , $3.69 and $2.63 per share during the years ended December 31, 2015 , 2014 and 2013 , respectively. The following table summarizes the activity of unvested restricted stock and RSUs: Number of Shares Weighted Average Grant Date Fair Value Unvested at December 31, 2014 367,126 $ 7.26 Granted 765,161 17.70 Vested (279,716 ) 11.93 Canceled/Forfeited (3,000 ) 7.75 Unvested at December 31, 2015 849,571 15.12 As of December 31, 2015 , total unrecognized compensation cost was $27.2 million related to unvested share-based compensation arrangements which is expected to be recognized over a weighted average period of 2.1 years. The total stock-based compensation cost capitalized in inventory was $0.3 million as of December 31, 2015 . The total stock-based compensation cost capitalized in inventory was insignificant as of December 31, 2014 and 2013 . The following table sets forth the stock-based compensation expense included in the consolidated statements of operations (in thousands): Year Ended December 31, 2015 2014 2013 Cost of sales $ 316 $ 267 $ 98 Research and development 444 96 84 Sales, general and administrative 6,511 1,070 704 $ 7,271 $ 1,433 $ 886

Common and Preferred Stock Repu

Common and Preferred Stock Repurchase	12 Months Ended
	Dec. 31, 2015
Equity [Abstract]
Initial Public Offering, Common Stock, Warrants, and Common and Preferred Stock Repurchase	Initial Public Offering (IPO) The Company closed its IPO on September 23, 2015, in which it sold 4.6 million shares of common stock at an offering price of $30.00 per share and raised $124.7 million in net proceeds after deducting underwriting discounts and commissions of $9.7 million and other offering expenses of $3.6 million . Upon the closing of the IPO, all outstanding shares of convertible preferred stock of the Company were automatically converted into 19,510,410 shares of common stock on a one -for-one basis. Common Stock Each share of common stock is entitled to one vote. The holders of common stock are also entitled to receive dividends whenever funds are legally available and when declared by the board of directors, subject to the prior rights of holders of all classes of stock outstanding. Warrants In connection with the sale of Series B preferred stock in 2004, the Company issued warrants to purchase 211,138 shares of common stock at a purchase price of $0.01 per share. The warrants were exercisable upon grant and had a term of 10 years from the date of grant, which expired on December 31, 2014 . The value of the warrants was calculated using Black-Scholes option pricing model and was deemed to be immaterial. No warrants were outstanding as of December 31, 2015 or 2014 . Common and Preferred Stock Repurchase The Company’s board of directors approved the repurchase of 70,612 shares of common stock, 45,000 stock options and 45,611 of preferred stock from shareholders in May 2014 for $13.20 per share for a total purchase price of $2.0 million . For the repurchased shares of common stock and stock options, the Company charged the difference between the purchase and market prices of $0.5 million to expense. For the repurchased preferred shares, the excess between the purchase and the issuance price of $0.5 million was treated as a deemed dividend. In addition, the Company closed a tender offer in July 2014 to repurchase shares of preferred stock from existing shareholders at a purchase price of $13.20 per share. The Company repurchased 584,052 shares of preferred stock for a total purchase price of $7.7 million . The excess between the purchase and the issuance price of $5.8 million was treated as a deemed dividend. The repurchased shares of common and preferred stock were retired and remained as authorized but unissued.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income	12 Months Ended
	Dec. 31, 2015
Equity [Abstract]
Accumulated Other Comprehensive Income	Accumulated Other Comprehensive Income Other comprehensive income consists of two components: unrealized gains or losses on the Company's available-for-sale marketable investments, and gains or losses from foreign currency translation adjustments. Until realized and reported as a component of net income, these comprehensive income items accumulate and are included within accumulated other comprehensive income. Unrealized gains and losses on our marketable investments are reclassified from accumulated other comprehensive income into earnings when realized upon sale, and are determined based on specific identification of securities sold. Gains and losses from the translation of assets and liabilities denominated in non-U.S. dollar functional currencies are included in accumulated other comprehensive income. The following table summarizes the changes in the accumulated balances during the period, and includes information regarding the manner in which the reclassifications out of accumulated other comprehensive income into earnings affect our consolidated statements of operations (in thousands): Year Ended December 31, 2015 Year Ended December 31, 2014 Marketable Currency Translation Total Marketable Currency Translation Total Balance, beginning of the year $ (220 ) $ (644 ) $ (864 ) $ 17 $ 779 $ 796 Other comprehensive income before reclassifications: Unrealized gains (losses)—marketable investments (417 ) — (417 ) (388 ) — (388 ) Foreign currency translation gains (losses) — (1,425 ) (1,425 ) — (1,668 ) (1,668 ) Income tax effect—benefit (expense) 128 117 245 161 245 406 Net of tax (289 ) (1,308 ) (1,597 ) (227 ) (1,423 ) (1,650 ) Amounts reclassified from accumulated other comprehensive income to earnings: Realized losses—marketable investments 540 — 540 (17 ) — (17 ) Income tax effect—benefit (194 ) — (194 ) 7 — 7 Net of tax 346 — 346 (10 ) — (10 ) Net current-year other comprehensive income (loss) 57 (1,308 ) (1,251 ) (237 ) (1,423 ) (1,660 ) Balance, end of the year $ (163 ) $ (1,952 ) $ (2,115 ) $ (220 ) $ (644 ) $ (864 )

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2015
Compensation and Retirement Disclosure [Abstract]
Employee Benefit Plans	Employee Benefit Plans The Company offers a retirement savings plan under Section 401(k) of the Internal Revenue Code (IRC) to its eligible U.S. employees whereby they may contribute up to the maximum amount permitted by the IRC. In the third quarter of 2015, the Company began 401(k) matching of eligible compensation under the plan, subject to a maximum dollar threshold. Contribution expense was $0.3 million for the year ended December 31, 2015 .

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company’s income tax expense (benefit), deferred tax assets and liabilities, and reserves for unrecognized tax benefits reflect management's best assessment of estimated current and future taxes to be paid. The Company is subject to income taxes in both the U. S. and foreign jurisdictions. Significant judgments and estimates are required in determining the consolidated income tax expense (benefit). The Company is incorporated in the U. S. and operates in various countries with differing tax laws and rates. A portion of the Company’s income or (loss) before taxes and the provision for (benefit from) income taxes are generated from international operations. Income or (loss) before income taxes for the years ended December 31, 2015 , 2014 and 2013 is summarized as follows: Year Ended December 31, 2015 2014 2013 United States $ 2,955 $ 2,230 $ (1,142 ) Foreign 1,069 909 (113 ) Total income (loss) before provision for (benefit from) income taxes $ 4,024 $ 3,139 $ (1,255 ) Income tax provision in 2015 , 2014 and 2013 is comprised of federal, state, and foreign taxes. The components of the provision for (benefit from) income taxes are summarized as follows: Year Ended December 31, 2015 2014 2013 Current: Federal $ 3,815 $ 1,155 $ (155 ) State 603 274 87 Foreign 492 323 — Total current 4,910 1,752 (68 ) Deferred: Federal (3,025 ) (625 ) (5,087 ) State (251 ) (116 ) (199 ) Foreign 25 (117 ) — Total deferred (3,251 ) (858 ) (5,286 ) Provision for (benefit from) income taxes $ 1,659 $ 894 $ (5,354 ) The Company’s actual provision for tax differed from the amounts computed by applying the U.S. federal income tax rate of 34% to pretax income as a result of the following: Year Ended December 31, 2015 2014 2013 Income tax at federal statutory rate 34.0 % 34.0 % 34.0 % State income taxes, net of federal benefit 1.9 3.2 (5.6 ) Foreign taxes differential (9.0 ) 5.2 5.8 Prepaid tax ASC 810-10 2.1 (8.9 ) (2.7 ) Foreign exchange gains and losses — — 11.7 IRC 199 deduction (7.4 ) (7.0 ) — Stock-based compensation 14.8 6.0 (14.1 ) Meals and entertainment 5.6 5.8 (10.7 ) Imputed interest 4.7 6.6 (12.1 ) Tax credits (11.6 ) (12.1 ) 41.8 Other 3.6 2.8 0.3 Change in valuation allowance 2.5 (7.1 ) 378.2 Effective tax rate 41.2 % 28.5 % 426.6 % Deferred income tax assets and liabilities consist of the following: December 31, 2015 2014 Deferred tax assets Net operating loss carryforwards $ 1,000 $ 1,626 Tax credits 1,355 1,779 Accruals and reserves 5,048 3,759 Stock-based compensation 1,352 416 Translation adjustment 715 674 UNICAP adjustments 3,840 2,227 Other 870 — Gross deferred tax assets 14,180 10,481 Valuation allowance (2,702 ) (2,945 ) Total deferred tax assets 11,478 7,536 Deferred tax liabilities Depreciation and amortization (1,335 ) (685 ) Total deferred tax liabilities (1,335 ) (685 ) Net deferred tax assets $ 10,143 $ 6,851 Deferred income taxes, net - Balance Sheet Classification Current deferred income tax assets $ — $ 6,280 Long-term deferred income tax assets 10,143 571 Net deferred tax assets $ 10,143 $ 6,851 The Company assesses the realizability of its net deferred tax assets by evaluating all available evidence, both positive and negative, including (1) cumulative results of operations in recent years, (2) sources of recent losses, (3) estimates of future taxable income and (4) the length of net operating loss carryforward periods. As of December 31, 2013 , the Company determined that it is more likely than not that a portion of the net deferred tax assets will be realized for federal and US states except California and released the valuation allowance of $5.0 million . As a result, the Company has maintained a full valuation allowance against the net deferred tax assets of California through December 31, 2015 . As of December 31, 2014 , the Company determined that it is more likely than not that German net deferred tax assets will be realized and released the German valuation allowance of $0.3 million . The net deferred tax assets was $10.1 million as of December 31, 2015 and was included in non-current deferred tax assets due to the adoption of FASB guidance discussed in Note 2 “ Summary of Significant Accounting Policies ” to the consolidated financial statements included in this Form 10-K. The valuation allowance against net deferred tax assets changed as follows: December 31, 2015 2014 2013 Balance at the beginning of the year $ 2,945 $ 3,860 $ 8,742 Release of valuation allowance (243 ) (321 ) (4,962 ) Other reserves and deferrals — (594 ) 80 Balance at the end of the year $ 2,702 $ 2,945 $ 3,860 At December 31, 2015 , the Company had approximately $16.3 million and $1.8 million of state and foreign net operating loss carryforwards, respectively, available to offset future taxable income. The state net operating loss carryforwards will begin to expire in 2017. At December 31, 2015 , the Company had research credits available to offset state tax liabilities in the amount of $3.6 million . California state tax credits have no expiration. The state net operating loss carryforwards of $16.3 million included $ 0.6 million relating to stock-based compensation deductions. These amounts are not included in the Company’s gross or net deferred tax assets pursuant to applicable accounting guidance and, if and when realized, through a reduction in income tax payable, will be accounted for as a credit to additional paid-in capital. IRC Sections 382 and 383 limit the use of net operating losses and business credits if there is a change in ownership. In 2009, the Company determined there were changes in ownership in 2004 and 2008, which did not cause any impairment of tax attributes. Included in the $3.6 million balance of unrecognized tax benefits as of December 31, 2015 is $1.3 million of tax benefits that, if recognized, would affect the effective tax rate. A reconciliation of the change in the gross unrecognized tax benefits from January 1, 2013 to December 31, 2015 , is as follows: December 31, 2015 2014 2013 Beginning Balance $ 1,726 $ 1,325 $ 838 Gross increase for tax positions of current year 1,023 401 324 Gross increase for tax positions of prior years 1,062 — 163 Settlements — — — Lapse of statute of limitations (192 ) — — Ending Balance $ 3,619 $ 1,726 $ 1,325 The Company recognizes interest and penalties related to uncertain tax positions in income tax expense. As of December 31, 2015 , the Company had $0.1 million accrued interest and penalties related to uncertain tax positions. The Company files U.S., state and foreign income tax returns in jurisdictions with varying statutes of limitations. Due to net operating loss and credit carryovers, the tax years ending December 31, 2004 through December 31, 2015 remain subject to examination by federal and state tax authorities. In Australia and Canada, tax years ending December 31, 2008 through December 31, 2015 generally remain subject to examination by tax authorities. In Germany, tax years ending December 31, 2013 through December 31, 2015 remain subject to examination by tax authorities. The Company does not anticipate any significant changes in the balance of gross unrecognized tax benefits over the next 12 months.

Net Income (Loss) per Share of

Net Income (Loss) per Share of Common Stock attributable to Common Stockholders	12 Months Ended
	Dec. 31, 2015
Earnings Per Share [Abstract]
Net Income (Loss) per Share of Common Stock attributable to Common Stockholders	Net Income (Loss) per Share of Common Stock attributable to Common Stockholders A reconciliation of the numerator and denominator used in the calculation of the basic and diluted net income (loss) per share attributable to common stockholders is as follows (in thousands, except share and per share amounts): Year Ended December 31, 2015 2014 2013 Net income (loss) per share: Numerator Net income $ 2,365 $ 2,245 $ 4,099 Less: Deemed dividend paid to convertible preferred stockholders upon repurchase — (6,344 ) — Less: Undistributed income attributable to convertible preferred stockholders (1,281 ) — (3,212 ) Add: Undistributed loss attributable to convertible preferred stockholders — 3,266 — Net income (loss) attributable to common stockholders—basic and diluted $ 1,084 $ (833 ) $ 887 Denominator Weighted average shares used to compute net income (loss) attributable to common stockholders—Basic 11,993,429 4,609,375 4,304,396 Potential dilutive options, as calculated using treasury stock method 1,959,226 — 2,021,394 Potential dilutive common stock warrants, as calculated using treasury stock method — — 86,985 Potential dilutive restricted stock, as calculated using treasury stock method 266,995 — 88,060 Weighted average shares used to compute net income (loss) attributable to common stockholders—Diluted 14,219,650 4,609,375 6,500,835 Net income (loss) per share attributable to common stockholders —Basic $ 0.09 $ (0.18 ) $ 0.21 —Diluted $ 0.08 $ (0.18 ) $ 0.14 The following outstanding shares of potentially dilutive securities were excluded from the computation of diluted net income (loss) per share of common stock for the periods presented, because the effect of including them would have been anti-dilutive: Year Ended December 31, 2015 2014 2013 Options to purchase common stock 1,321,250 2,933,757 63,750 Restricted stock and restricted stock units 96,800 367,126 — Total 1,418,050 3,300,883 63,750

Geographic Areas and Product Sa

Geographic Areas and Product Sales	12 Months Ended
	Dec. 31, 2015
Segment Reporting [Abstract]
Geographic Areas and Product Sales	Geographic Areas and Product Sales The Company’s revenue by geographic area, based on the destination to which the Company ships its products, was as follows (in thousands): Year Ended December 31, 2015 2014 2013 United States $ 127,311 $ 82,965 $ 58,305 Japan 19,016 14,699 12,668 Other International 39,768 27,846 17,875 Total $ 186,095 $ 125,510 $ 88,848 The following table sets forth revenue by product category (in thousands): Year Ended December 31, 2015 2014 2013 Neuro $ 141,410 $ 106,242 $ 81,343 Peripheral Vascular 44,685 19,268 7,505 Total $ 186,095 $ 125,510 $ 88,848 The Company does not have significant long-lived assets outside the U.S.

Selected Quarterly Financial Da

Selected Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Selected Quarterly Financial Data (Unaudited)	Selected Quarterly Financial Data (Unaudited) The following table provides the selected quarterly financial data for 2015 and 2014 (in thousands, except share and per share amounts): Quarter Ended 2015 2014 December 31 September 30 June 30 March 31 December 31 September 30 June 30 March 31 Revenue $ 54,416 $ 50,416 $ 42,311 $ 38,952 $ 35,403 $ 32,464 $ 31,480 $ 26,163 Cost of revenue 17,958 16,919 14,936 12,224 11,512 11,667 10,780 8,709 Gross profit $ 36,458 $ 33,497 $ 27,375 $ 26,728 $ 23,891 $ 20,797 $ 20,700 $ 17,454 Income (loss) before provision for (benefit from) income taxes $ 1,876 $ 2,084 $ (4,178 ) $ 4,242 $ 417 $ 399 $ 526 $ 1,797 Net income (loss) $ 1,633 $ 901 $ (2,671 ) $ 2,502 $ 416 $ 172 $ 391 $ 1,266 Net income (loss) attributable to common stockholders $ 1,633 $ 276 $ (553 ) $ 503 $ 81 $ (1,192 ) $ 81 $ 280 Net income (loss) per share attributable to common stockholders—Basic $ 0.05 $ 0.04 $ (0.11 ) $ 0.10 $ 0.02 $ (0.25 ) $ 0.02 $ 0.06 Net income (loss) per share attributable to common stockholders—Diluted $ 0.05 $ 0.03 $ (0.11 ) $ 0.07 $ 0.01 $ (0.25 ) $ 0.01 $ 0.04 Weighted average shares used to compute net income (loss) per share attributable to common stockholders—Basic 29,890,944 7,853,730 5,096,151 4,903,535 4,701,999 4,688,045 4,608,510 4,430,824 Weighted average shares used to compute net income (loss) per share attributable to common stockholders—Diluted 32,321,410 10,189,248 5,096,151 7,193,452 7,102,885 4,688,045 6,868,889 6,705,066

Summary of Significant Accoun27

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Basis of Presentation and Consolidation	Basis of Presentation and Consolidation The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (U.S. GAAP). The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities and equity accounts; disclosure of contingent assets and liabilities at the date of the financial statements; and the reported amounts of revenues and expenses during the reporting period. On an ongoing basis, the Company evaluates its estimates, including those related to provisions for doubtful accounts, sales return reserve, warranty reserves, valuation of inventories, useful lives of property and equipment, income taxes, the valuation of equity instruments and contingencies, among others. The Company bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other data. Actual results could differ from those estimates.
Segments	Segments The Company determined its operating segment on the same basis that it uses to evaluate its performance internally. The Company has one business activity: the design, development, manufacturing and marketing of innovative medical devices, and operates as one operating segment. The Company’s chief operating decision-maker, its Chief Executive Officer, reviews its operating results for the purpose of allocating resources and evaluating financial performance. The Company determines revenue by geographic area, based on the destination to which it ships its products.
Foreign Currency Translation	Foreign Currency Translation The Company’s consolidated financial statements are prepared in United States Dollars (USD). Its foreign subsidiaries use their local currency as their functional currency and maintain their records in the local currency. Accordingly, the assets and liabilities of these subsidiaries are translated into USD using the current exchange rates in effect at the balance sheet date and equity accounts are translated into USD using historical rates. Revenues and expenses are translated using the average exchange rates in effect for the year involved. The resulting foreign currency translation adjustments are recorded in accumulated other comprehensive income in the consolidated balance sheets. Transactions denominated in foreign currency are translated at exchange rates at the date of transaction with foreign currency gains (losses) recorded in other income (expense), net in the consolidated statements of operations and comprehensive income. The Company recognized net foreign currency transaction losses of $0.1 million , $0.3 million and $0.3 million during the years ended December 31, 2015 , 2014 and 2013 , respectively. As the Company’s international operations grow, its risks associated with fluctuation in currency rates will become greater, and the Company will continue to reassess its approach to managing this risk. In addition, currency fluctuations or a weakening USD can increase the costs of the Company’s international expansion. To date, the Company has not entered into any foreign currency hedging contracts, since exchange rate fluctuations have not had a material impact on its operating results and cash flows.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash and cash equivalents, marketable investments and accounts receivable. The majority of the Company’s cash is held by one financial institution in the U. S. in excess of federally insured limits. The Company maintained investments in money market funds that were not federally insured during the year ended December 31, 2015 and held cash in foreign banks of approximately $1.9 million and $0.8 million at December 31, 2015 and 2014 , respectively, that was not federally insured. All of the Company’s revenue has been derived from sales of its products in the U. S. and international markets. The Company uses both its own salesforce and independent distributors to sell its products. Concentrations of credit risk with respect to accounts receivable are limited due to the large number of entities comprising the Company’s customer base. The Company performs ongoing credit evaluations of its customers, including its distributors, does not require collateral, and maintains allowances for potential credit losses on customer accounts when deemed necessary.
Significant Risks and Uncertainties	Significant Risks and Uncertainties The Company is subject to risks common to medical device companies including, but not limited to, new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with government regulations, product liability, uncertainty of market acceptance of products and the potential need to obtain additional financing. The Company is dependent on third party suppliers, in some cases single-source suppliers. There can be no assurance that the Company’s products will continue to be accepted in the marketplace, nor can there be any assurance that any future products can be developed or manufactured at an acceptable cost and with appropriate performance characteristics, or that such products will be successfully marketed, if at all. The Company’s products require approval or clearance from the U.S. Food and Drug Administration prior to commencing commercial sales in the U. S. . There can be no assurance that the Company’s products will receive all of the required approvals or clearances. Approvals or clearances are also required in foreign jurisdictions in which the Company sells its products. If the Company is denied such approvals or clearances or such approvals or clearances are delayed, it may have a material adverse impact on the Company’s results of operations, financial position and liquidity.
Fair Value of Financial Instruments	Fair Value of Financial Instruments Carrying amounts of certain of the Company’s financial instruments, including cash equivalents, accounts receivable, prepaid expenses and other current assets, accounts payable and accrued liabilities, approximate fair value due to their relatively short maturities.
Cash and Cash Equivalents	Cash, Cash Equivalents and Marketable Investments The Company invests its cash primarily in money market funds and in highly liquid debt instruments of U.S. federal and municipal governments, and their agencies, and corporate debt securities. All highly liquid investments with stated maturities of three months or less from the date of purchase are classified as cash equivalents; all highly liquid investments with stated maturities of greater than three months are classified as marketable investments. The majority of the Company’s cash and investments are held in U.S. banks.
Marketable Investments	The Company determines the appropriate classification of its investments in marketable investments at the time of purchase and re-evaluates such designation at each balance sheet date. The Company’s marketable investments have been classified and accounted for as available-for-sale. Investments with remaining maturities of more than one year are viewed by the Company as available to support current operations and are classified as current assets under the caption marketable investments in the accompanying consolidated balance sheets. Investments in marketable investments are carried at fair value, with the unrealized gains and losses reported as a component of accumulated other comprehensive loss. Any realized gains or losses on the sale of marketable investments are determined on a specific identification method, and such gains and losses are reflected as a component of other income (expense), net. Impairment of Marketable Investments After determining the fair value of available-for-sale debt instruments, unrealized gains or losses on these securities are recorded to accumulated other comprehensive income (loss) until either the security is sold or the Company determines that the decline in value is other-than-temporary. The primary differentiating factors that the Company considers in classifying impairments as either temporary or other-than-temporary impairments is the intent and ability to retain the investment in the issuer for a period of time sufficient to allow for any anticipated recovery in market value, the length of the time and the extent to which the market value of the investment has been less than cost, the financial condition and near-term prospects of the issuer.
Accounts Receivable	Accounts Receivable Accounts receivable are stated at invoice value less estimated allowances for doubtful accounts. The Company continually monitors customer payments and maintains a reserve 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, and thereby reduces the net recognized receivable to the amount reasonably believed to be collectible.
Inventories	Inventories Inventories are stated at the lower of cost (determined under the first-in first-out method) or market. Write downs are provided for raw materials, components or finished goods that are determined to be excessive or obsolete. Market value is determined as the lower of replacement cost or net realizable value. The Company regularly reviews inventory quantities in consideration of actual loss experience, projected future demand and remaining shelf life to record a provision for excess and obsolete inventory when appropriate. The estimate of excess quantities is subjective and primarily dependent on the Company’s estimates of future demand for a particular product or components or raw materials used in the manufacturing of such product. If the estimate of future demand is inaccurate based on actual sales, the Company may increase the write down for excess inventory and record a charge to inventory impairment in the accompanying consolidated statements of operations and comprehensive income. The Company periodically evaluates the carrying value of inventory on hand for potential excess amounts over demand using the same lower of cost or market approach that has been used to value the inventory. The Company also periodically evaluates inventory quantities in consideration of actual loss experience.
Property and Equipment, Net	Property and Equipment, net Property and equipment are stated at cost less accumulated depreciation. Depreciation is computed using the straight-line method over five years, which is the estimated useful lives of the assets. Leasehold improvements are amortized using the straight-line method over the shorter of the lease term or estimated useful life. Upon retirement or sale, the cost and the related accumulated depreciation are removed from the consolidated balance sheet and the resulting gain or loss is reflected in operations. Maintenance and repairs are charged to operations as incurred.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company reviews long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. When such an event occurs, management determines whether there has been impairment by comparing the anticipated undiscounted future net cash flows to the related asset group’s carrying value. If an asset is considered impaired, the asset is written down to fair value, which is determined based either on discounted cash flows or appraised value, depending on the nature of the asset.
Convertible Preferred Stock	Convertible Preferred Stock The Company, prior to the closing of its initial public offering (IPO) on September 23, 2015, classified its outstanding convertible preferred stock as temporary equity in the consolidated balance sheet due to the existence of certain change in control events that were not solely within the Company’s control, including liquidation, sale or transfer of the Company, that could trigger the ability of the holders of the convertible preferred stock to call for redemption of shares. Upon the closing of the IPO, all outstanding shares of convertible preferred stock automatically converted into shares of common stock on a one -for-one basis.
Revenue Recognition	Revenue Recognition Revenue is comprised of product revenue net of returns, discounts, administration fees and sales rebates. The Company recognizes revenue when persuasive evidence of an arrangement exists, delivery has occurred, the sales price is fixed or determinable and collectability is reasonably assured. Evidence of an arrangement consists of customer orders and the Company typically considers delivery to have occurred once title and risk of loss has been transferred and the product has been delivered to the customer. The Company typically recognizes revenue when products are delivered to hospital customers or distributors. However, with respect to products that the Company consigns to hospitals, which primarily consist of coils, the Company recognizes revenue at the time hospitals utilize products in a procedure. Deferred revenue represents amounts that the Company has already invoiced its customers and that are ultimately expected to be recognized as revenue, but for which not all revenue recognition criteria have been met. The Company had a deferred revenue balance of $0.6 million and $1.6 million , as of December 31, 2015 and 2014 , respectively. The Company’s terms and conditions permit product returns and exchanges, and it records returns reserves in the period when revenue is recognized. Estimates are based on actual historical returns over the prior three years and are recorded as reductions in revenue at the time of sale. Upon recognition, the Company reduces revenue and cost of revenue for the estimated return. Return rates can fluctuate over time, but are sufficiently predictable to allow the Company to estimate expected future product returns.
Cost of Revenue	Cost of Revenue Cost of revenue includes direct and indirect costs associated with the manufacture of the Company’s products. Direct costs include material and labor, while indirect costs include inbound freight charges, receiving costs, inspection and testing costs, warehousing costs, royalty expense and other labor and overhead costs incurred in the manufacturing of products. Cost of revenue also includes stock-based compensation, warranty replacement costs, cost of revenue related to product return reserves and excess and obsolete inventory write-downs.
Shipping Costs	Shipping Costs Shipping and handling costs charged to customers are recorded as revenue. Shipping and handling costs are included in cost of revenue.
Research and Development (R&D) Costs	Research and Development (R&D) Costs R&D costs primarily consist of product development, clinical and regulatory expenses, materials, depreciation and other costs associated with the development of the Company’s products. R&D costs also include related personnel and consultants’ salaries, benefits and related costs, including stock-based compensation. The Company expenses R&D costs as they are incurred. The Company’s clinical trial accruals are based on estimates of patient enrollment and related costs at clinical investigator sites. The Company estimates preclinical and clinical trial expenses based on the services performed pursuant to contracts with research institutions and clinical research organizations that conduct and manage preclinical studies and clinical trials on its behalf. In accruing service fees, the Company estimates the time period over which services will be performed and the level of patient enrollment and activity expended in each period. If the actual timing of the performance of services or the level of effort varies from the estimate, the Company will adjust the accrual accordingly. Payments made to third parties under these arrangements in advance of the receipt of the related services are recorded as prepaid expenses until the services are rendered.
Advertising Costs	Advertising Costs Advertising costs are included in sales, general and administrative expenses and are expensed as incurred. Advertising costs consist primarily of trade show and booth costs, product demonstration, and marketing materials.
Stock-Based Compensation	Stock-Based Compensation The Company recognizes the cost of stock-based compensation in the financial statements based upon fair value. The fair value of restricted stock and restricted stock unit (RSU) awards is determined based on the number of units granted and the closing price of the Company’s common stock as of the grant date. The fair value of stock options is determined as of the grant date using the Black-Scholes option pricing model. The Company’s determination of the fair value of stock options is impacted by the price of the Company's common stock as well as changes in assumptions regarding a number of highly complex and subjective variables. These variables include, but are not limited to, the expected term that options will remain outstanding, expected common stock price volatility over the term of the option awards, risk-free interest rates and expected dividends. The fair value of an option award is recognized over the period during which an optionee is required to provide services in exchange for the option award, known as the requisite service period (usually the vesting period) on a straight-line basis. Stock-based compensation expense recognized at fair value includes the impact of estimated forfeitures. The Company estimates future forfeitures at the date of grant and revises the estimates, if necessary, in subsequent periods if actual forfeitures differ from those estimates. To the extent actual forfeiture results differ from the estimates, the difference is recorded as a cumulative adjustment in the period forfeiture estimates are revised. No compensation cost is recorded for options that do not vest. Equity instruments issued to non-employees are recorded at their fair value on the measurement date and are subject to periodic adjustments as the underlying equity instruments vest. The fair value of these equity instruments are expensed over the service period. Estimates of the fair value of equity-settled awards as of the grant date using valuation models, such as the Black-Scholes option pricing model, are affected by assumptions regarding a number of complex variables. Changes in the assumptions can materially affect the fair value of the award and ultimately how much stock-based compensation expense is recognized. These inputs are subjective and generally require significant analysis and judgment to develop. For all stock options granted to date, the Company estimated the volatility data based on a study of publicly traded industry peer companies. For purposes of identifying these peer companies, the Company considered the industry, stage of development, size and financial leverage of potential comparable companies. The risk-free interest rate is based on the yield available on U.S. Treasury zero-coupon issues similar in duration to the expected term of the equity-settled award. The Company uses the Staff Accounting Bulletin, No. 110 ( SAB 110) simplified method to calculate the expected term, which is the average of the contractual term and vesting period.
Income Taxes	Income Taxes The Company accounts for income taxes using the asset and liability method, whereby deferred tax asset and liability account balances are determined based on differences between the financial reporting and tax bases of assets and liabilities, and are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse. The Company provides a valuation allowance to reduce the net deferred tax assets to their estimated realizable value. The calculation of the Company’s current provision for income taxes involves the use of estimates, assumptions and judgments while taking into account current tax laws, interpretation of current tax laws and possible outcomes of future tax audits. The Company has established reserves to address potential exposures related to tax positions that could be challenged by tax authorities. Although the Company believes its estimates, assumptions and judgments to be reasonable, any changes in tax law or its interpretation of tax laws and the resolutions of potential tax audits could significantly impact the amounts provided for income taxes in the Company’s consolidated financial statements. The calculation of the Company’s deferred tax asset balance involves the use of estimates, assumptions and judgments while taking into account estimates of the amounts and type of future taxable income. Actual future operating results and the underlying amount and type of income could differ materially from the Company’s estimates, assumptions and judgments thereby impacting the Company’s financial position and results of operations. The Company follows the guidance relating to accounting for uncertainty in income taxes, which prescribes a recognition threshold and measurement attribute for the financial statement recognition and measurement of uncertain tax positions taken or expected to be taken in the Company’s income tax return, and also provides guidance on derecognition, classification, interest and penalties, accounting in interim periods and disclosure. The Company includes interest and penalties related to unrecognized tax benefits within income tax expense in the accompanying consolidated statements of operations.
Comprehensive Income	Comprehensive Income The Company is required to display comprehensive income and its components as part of the Company’s consolidated financial statements. Comprehensive income consists of net income, unrealized gains or losses on available-for-sale investments and the effects of foreign currency translation.
Net Income (Loss) Per Share of Common Stock	Net Income (Loss) Per Share of Common Stock The Company, for the periods prior to the closing of the IPO, calculated its basic and diluted net income (loss) per share attributable to common stockholders in conformity with the two-class method required for companies with participating securities. Under the two-class method, the Company determined whether it had net income (loss) attributable to common stockholders, which included the results of operations less current period preferred stock non-cumulative dividends. If it was determined that the Company did have net income (loss) attributable to common stockholders during a period, the related undistributed earnings were then allocated between common stock and the preferred stock based on the weighted average number of shares outstanding during the period to determine the numerator for the basic net income (loss) per share attributable to common stockholders. In computing diluted net income attributable to common stockholders, undistributed earnings were re-allocated to reflect the potential impact of dilutive securities to determine the numerator for the diluted net income per share attributable to common stockholders. The Company’s basic net income (loss) per share attributable to common stockholders is calculated by dividing the net income (loss) by the weighted average number of shares of common stock outstanding for the period. The diluted net income per share attributable to common stockholders is computed by giving effect to all potential dilutive common stock equivalents outstanding for the period. For purposes of this calculation, options to purchase common stock, restricted stock, RSUs and common stock warrants are considered common stock equivalents.
Recently Issued Accounting Standards	Recently Issued Accounting Standards In May 2014, the Financial Accounting Standards Board (FASB) issued ASU No. 2014-09, Revenue from Contracts with Customers , which outlines a comprehensive new revenue recognition model designed to depict the transfer of promised 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. In August 2015, the FASB issued ASU No. 2015-14, Revenue from Contracts with Customers — Deferral of the Effective Date to defer the effective date by one year for annual reporting periods beginning after December 15, 2017, including interim reporting periods within that reporting period. Earlier adoption is permitted only as of annual reporting periods beginning after December 15, 2016, including interim reporting periods within that reporting period. The Company is currently evaluating the impact of this accounting standard. In July 2015, the FASB issued ASU No. 2015-11, Simplifying the Measurement of Inventory , which requires an entity to measure most inventory at the lower of cost and net realizable value, thereby simplifying the current guidance under which an entity must measure inventory at the lower of cost or market. The accounting standard is effective prospectively for annual periods beginning after December 15, 2016, and interim periods therein. Early adoption is permitted as of the beginning of an interim or annual reporting period. The Company is currently evaluating the impact of this accounting standard. In November 2015, the FASB issued ASU No. 2015-17, Balance Sheet Classification of Deferred Taxes , which requires that deferred tax assets and liabilities be classified as non-current in a classified statement of financial position. The accounting standard is effective, either prospectively to all deferred tax assets and liabilities or retrospectively to all periods presented, for annual periods beginning after December 15, 2016, and interim periods therein. Early adoption is permitted as of the beginning of an interim or annual reporting period. The Company early adopted this standard as of December 31, 2015 on a prospective basis. In January 2016, the FASB issued ASU 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities , which addresses certain aspects of recognition, measurement, presentation and disclosure of financial instruments . The new standard is effective for annual periods and interim periods beginning after December 15, 2017, and upon adoption, an entity should apply the amendments by means of a cumulative-effect adjustment to the balance sheet at the beginning of the first reporting period in which the guidance is effective. Early adoption is not permitted except for the provision to record fair value changes for financial liabilities under the fair value option resulting from instrument-specific credit risk in other comprehensive income. The Company is currently evaluating the impact of adopting this guidance. In February 2016, the FASB issued ASU 2016-02, Leases , which requires to recognize and measure leases at the beginning of the earliest period presented using a modified retrospective approach. The accounting standard is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early adoption is permitted. The Company is currently evaluating the impact of adopting this guidance.

Fair Value of Financial Instr28

Fair Value of Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2015
Fair Value Disclosures [Abstract]
Schedule of Fair Value of Assets and Liabilities	The following tables set forth the Company’s financial assets and liabilities measured at fair value by level within the fair value hierarchy (in thousands): As of December 31, 2015 Level 1 Level 2 Level 3 Fair Value Financial Assets Cash equivalents: Commercial paper $ — $ 9,850 $ — $ 9,850 Money market funds 252 — — 252 Marketable investments: Commercial paper — 22,332 — 22,332 U.S. Treasury 15,436 — — 15,436 U.S. Agency securities — 21,464 — 21,464 U.S. States and Municipalities — 2,084 — 2,084 Corporate bonds — 61,002 — 61,002 Non-U.S. Government debt securities — 6,939 — 6,939 Total $ 15,688 $ 123,671 $ — $ 139,359 As of December 31, 2014 Level 1 Level 2 Level 3 Fair Value Financial Assets Cash equivalents: Money market funds $ 155 $ — $ — $ 155 Marketable investments: Mutual funds 8,619 — — 8,619 U.S. Treasury 4,009 — — 4,009 U.S. Agency securities — 6,006 — 6,006 Corporate bonds — 29,619 — 29,619 Total $ 12,783 $ 35,625 $ — $ 48,408

Balance Sheet Components (Table

Balance Sheet Components (Tables)	12 Months Ended
	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Allowance for Doubtful Accounts	The Company’s allowance for doubtful accounts comprised of the following (in thousands): Balance At Charged To Deductions Balance At For the year ended: December 31, 2013 $ 212 $ 259 $ — $ 471 December 31, 2014 471 150 (19 ) 602 December 31, 2015 602 (13 ) — 589
Schedule of Prepaid Expenses and Other Current Assets	The Company’s prepaid expenses and other current assets comprised of the following (in thousands): December 31, 2015 2014 Prepaid expenses $ 7,442 $ 3,130 Income tax receivable 606 1,654 Other current assets 1,304 331 Prepaid expenses and other current assets $ 9,352 $ 5,115
Schedule of Marketable Investments	The Company’s marketable investments as of December 31, 2015 and 2014 were as follows (in thousands): December 31, 2015 Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Commercial paper $ 22,328 $ 5 $ (1 ) $ 22,332 U.S. Treasury 15,459 4 (27 ) 15,436 U.S. Agency securities 21,497 1 (34 ) 21,464 U.S. States and Municipalities 2,086 — (2 ) 2,084 Corporate bonds 61,188 3 (189 ) 61,002 Non-U.S. Government debt securities 6,954 1 (16 ) 6,939 Total $ 129,512 $ 14 $ (269 ) $ 129,257 December 31, 2014 Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value U.S. Agency securities $ 6,012 $ 3 $ (9 ) $ 6,006 U.S. Treasury 4,011 — (2 ) 4,009 Corporate bonds 29,834 4 (219 ) 29,619 Mutual funds 8,768 — (149 ) 8,619 Total $ 48,625 $ 7 $ (379 ) $ 48,253
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	The following tables present the gross unrealized losses and the fair value for those marketable investments that were in an unrealized loss position for less than twelve months as of December 31, 2015 and 2014 (in thousands): December 31, 2015 Fair Value Gross Unrealized Losses Commercial paper $ 4,746 $ (1 ) US Treasury 12,453 (27 ) US Agency securities 13,475 (34 ) US States and Municipalities 2,084 (2 ) Corporate bonds 59,163 (189 ) Non-U.S. government debt securities 5,881 (16 ) Total $ 97,802 $ (269 ) December 31, 2014 Fair Value Gross Unrealized Losses Mutual Funds $ 8,619 $ (149 ) US Treasury 3,008 (2 ) US Agency Securities 5,255 (9 ) Corporate Bonds 26,633 (219 ) Total $ 43,515 $ (379 )
Schedule of Contractual Maturities of Marketable Investments	The contractual maturities of the Company’s marketable investments as of December 31, 2015 and 2014 were as follows (in thousands): December 31, 2015 2014 Marketable Investments Fair Value Fair Value Due in one year $ 62,983 $ 16,442 Due in one to five years 66,274 31,811 Total $ 129,257 $ 48,253
Schedule of Inventories	The components of inventories consisted of the following (in thousands): December 31, 2015 2014 Raw materials $ 9,176 $ 5,105 Work in process 2,746 543 Finished goods 44,839 27,803 Inventories $ 56,761 $ 33,451
Schedule of Property and Equipment, Net	Property and equipment, net consisted of the following (in thousands): December 31, 2015 2014 Machinery and equipment $ 8,559 $ 5,089 Furniture and fixtures 2,091 519 Leasehold improvements 1,564 379 Software 666 599 Computers 565 153 Construction in progress 577 1,931 Total property and equipment 14,022 8,670 Less: Accumulated depreciation and amortization (5,071 ) (3,489 ) Property and equipment, net $ 8,951 $ 5,181
Schedule of Accrued Liabilities	The following table shows the components of accrued liabilities (in thousands): December 31, 2015 2014 Payroll and employee-related expenses $ 13,653 $ 8,221 Sales return reserve 3,247 2,164 Preclinical and clinical trial cost 1,330 2,319 Deferred revenue 526 1,591 Product warranty 713 314 Sales tax payable 531 306 Income tax payable 308 332 Other accrued liabilities 5,273 3,228 Total accrued liabilities $ 25,581 $ 18,475
Schedule of Estimated Product Warranty Accrual	The estimated product warranty accrual was as follows (in thousands): December 31, 2015 2014 2013 Balance at the beginning of the year $ 314 $ 323 $ 323 Accruals of warranties issued 752 149 100 Settlements of warranty claims (353 ) (158 ) (100 ) Balance at the end of the year $ 713 $ 314 $ 323

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Lease Payments under Operating Leases	Future minimum lease payments under the non-cancelable operating leases as of December 31, 2015 are as follows (in thousands): Lease Payments Year Ending December 31: 2016 $ 4,055 2017 4,861 2018 4,877 2019 5,007 2020 5,133 Thereafter 52,555 Total future minimum lease payments $ 76,488

Convertible Preferred Stock (Ta

Convertible Preferred Stock (Tables)	12 Months Ended
	Dec. 31, 2015
Temporary Equity Disclosure [Abstract]
Schedule of Convertible Preferred Stock	The convertible preferred stock at December 31, 2014 consisted of the following (in thousands, except shares): Series Shares Authorized Shares Issued and Outstanding Proceeds, Net of Issuance Costs Aggregate Liquidation Amount Series A Preferred Stock 1,000,000 1,000,000 $ 299 $ 554 Series B Preferred Stock 4,287,486 4,005,338 6,536 11,725 Series C Preferred Stock 4,388,715 4,168,218 13,266 22,238 Series D Preferred Stock 3,944,733 3,881,459 19,647 30,976 Series E Preferred Stock 1,973,684 1,909,940 14,507 21,609 Series F Preferred Stock 5,303,031 4,545,455 57,212 62,259 Undesignated 4,102,351 — — — Total convertible preferred stock 25,000,000 19,510,410 $ 111,467 $ 149,361

Stock Option Plans (Tables)

Stock Option Plans (Tables)	12 Months Ended
	Dec. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Stock Option Activity	Activity of stock options under 2005 Plan, 2011 Plan and 2014 Plan is set forth below: Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Life (in Years) Aggregate Intrinsic Value (in thousands) Balance, December 31, 2014 2,900,676 $ 2.66 Granted 1,809,400 21.47 Exercised (948,872 ) 0.99 Canceled/Forfeited (5,859 ) 11.15 Balance, December 31, 2015 3,755,345 $ 12.13 Vested and expected to vest—December 31, 2015 3,621,919 $ 11.79 6.70 $ 152,187 Exercisable—December 31, 2015 1,941,150 $ 3.47 4.20 $ 97,717
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions	The Company used the following assumptions in its Black-Scholes option pricing model to determine the fair value of stock options: Year Ended December 31, 2015 2014 2013 Expected term (in years) 6.08—6.25 6.25 6.25 Expected volatility 45% 45% 45% Risk-free interest rate 1.56%—1.78% 1.76%—2.02% 0.63%—0.90% Expected dividend rate 0% 0% 0%
Summary of Unvested Restricted Stock Activity	The following table summarizes the activity of unvested restricted stock and RSUs: Number of Shares Weighted Average Grant Date Fair Value Unvested at December 31, 2014 367,126 $ 7.26 Granted 765,161 17.70 Vested (279,716 ) 11.93 Canceled/Forfeited (3,000 ) 7.75 Unvested at December 31, 2015 849,571 15.12
Schedule of Stock-based Compensation Expense	The following table sets forth the stock-based compensation expense included in the consolidated statements of operations (in thousands): Year Ended December 31, 2015 2014 2013 Cost of sales $ 316 $ 267 $ 98 Research and development 444 96 84 Sales, general and administrative 6,511 1,070 704 $ 7,271 $ 1,433 $ 886

Accumulated Other Comprehensi33

Accumulated Other Comprehensive Income (Tables)	12 Months Ended
	Dec. 31, 2015
Equity [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	The following table summarizes the changes in the accumulated balances during the period, and includes information regarding the manner in which the reclassifications out of accumulated other comprehensive income into earnings affect our consolidated statements of operations (in thousands): Year Ended December 31, 2015 Year Ended December 31, 2014 Marketable Currency Translation Total Marketable Currency Translation Total Balance, beginning of the year $ (220 ) $ (644 ) $ (864 ) $ 17 $ 779 $ 796 Other comprehensive income before reclassifications: Unrealized gains (losses)—marketable investments (417 ) — (417 ) (388 ) — (388 ) Foreign currency translation gains (losses) — (1,425 ) (1,425 ) — (1,668 ) (1,668 ) Income tax effect—benefit (expense) 128 117 245 161 245 406 Net of tax (289 ) (1,308 ) (1,597 ) (227 ) (1,423 ) (1,650 ) Amounts reclassified from accumulated other comprehensive income to earnings: Realized losses—marketable investments 540 — 540 (17 ) — (17 ) Income tax effect—benefit (194 ) — (194 ) 7 — 7 Net of tax 346 — 346 (10 ) — (10 ) Net current-year other comprehensive income (loss) 57 (1,308 ) (1,251 ) (237 ) (1,423 ) (1,660 ) Balance, end of the year $ (163 ) $ (1,952 ) $ (2,115 ) $ (220 ) $ (644 ) $ (864 )

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Schedule of Income or (Loss) before Income Taxes	Income or (loss) before income taxes for the years ended December 31, 2015 , 2014 and 2013 is summarized as follows: Year Ended December 31, 2015 2014 2013 United States $ 2,955 $ 2,230 $ (1,142 ) Foreign 1,069 909 (113 ) Total income (loss) before provision for (benefit from) income taxes $ 4,024 $ 3,139 $ (1,255 )
Components of the Provision for (Benefit from) Income Taxes	The components of the provision for (benefit from) income taxes are summarized as follows: Year Ended December 31, 2015 2014 2013 Current: Federal $ 3,815 $ 1,155 $ (155 ) State 603 274 87 Foreign 492 323 — Total current 4,910 1,752 (68 ) Deferred: Federal (3,025 ) (625 ) (5,087 ) State (251 ) (116 ) (199 ) Foreign 25 (117 ) — Total deferred (3,251 ) (858 ) (5,286 ) Provision for (benefit from) income taxes $ 1,659 $ 894 $ (5,354 )
Schedule of Effective Income Tax Reconciliation	The Company’s actual provision for tax differed from the amounts computed by applying the U.S. federal income tax rate of 34% to pretax income as a result of the following: Year Ended December 31, 2015 2014 2013 Income tax at federal statutory rate 34.0 % 34.0 % 34.0 % State income taxes, net of federal benefit 1.9 3.2 (5.6 ) Foreign taxes differential (9.0 ) 5.2 5.8 Prepaid tax ASC 810-10 2.1 (8.9 ) (2.7 ) Foreign exchange gains and losses — — 11.7 IRC 199 deduction (7.4 ) (7.0 ) — Stock-based compensation 14.8 6.0 (14.1 ) Meals and entertainment 5.6 5.8 (10.7 ) Imputed interest 4.7 6.6 (12.1 ) Tax credits (11.6 ) (12.1 ) 41.8 Other 3.6 2.8 0.3 Change in valuation allowance 2.5 (7.1 ) 378.2 Effective tax rate 41.2 % 28.5 % 426.6 %
Schedule of Deferred Tax Assets and Liabilities	Deferred income tax assets and liabilities consist of the following: December 31, 2015 2014 Deferred tax assets Net operating loss carryforwards $ 1,000 $ 1,626 Tax credits 1,355 1,779 Accruals and reserves 5,048 3,759 Stock-based compensation 1,352 416 Translation adjustment 715 674 UNICAP adjustments 3,840 2,227 Other 870 — Gross deferred tax assets 14,180 10,481 Valuation allowance (2,702 ) (2,945 ) Total deferred tax assets 11,478 7,536 Deferred tax liabilities Depreciation and amortization (1,335 ) (685 ) Total deferred tax liabilities (1,335 ) (685 ) Net deferred tax assets $ 10,143 $ 6,851 Deferred income taxes, net - Balance Sheet Classification Current deferred income tax assets $ — $ 6,280 Long-term deferred income tax assets 10,143 571 Net deferred tax assets $ 10,143 $ 6,851
Summary of Valuation Allowance	The valuation allowance against net deferred tax assets changed as follows: December 31, 2015 2014 2013 Balance at the beginning of the year $ 2,945 $ 3,860 $ 8,742 Release of valuation allowance (243 ) (321 ) (4,962 ) Other reserves and deferrals — (594 ) 80 Balance at the end of the year $ 2,702 $ 2,945 $ 3,860
Schedule of Unrecognized Tax Benefits	A reconciliation of the change in the gross unrecognized tax benefits from January 1, 2013 to December 31, 2015 , is as follows: December 31, 2015 2014 2013 Beginning Balance $ 1,726 $ 1,325 $ 838 Gross increase for tax positions of current year 1,023 401 324 Gross increase for tax positions of prior years 1,062 — 163 Settlements — — — Lapse of statute of limitations (192 ) — — Ending Balance $ 3,619 $ 1,726 $ 1,325

Net Income (Loss) per Share o35

Net Income (Loss) per Share of Common Stock attributable to Common Stockholders (Tables)	12 Months Ended
	Dec. 31, 2015
Earnings Per Share [Abstract]
Reconciliation of the Numerator and Denominator used in the Calculation of the Basic and Diluted Earnings per Share	A reconciliation of the numerator and denominator used in the calculation of the basic and diluted net income (loss) per share attributable to common stockholders is as follows (in thousands, except share and per share amounts): Year Ended December 31, 2015 2014 2013 Net income (loss) per share: Numerator Net income $ 2,365 $ 2,245 $ 4,099 Less: Deemed dividend paid to convertible preferred stockholders upon repurchase — (6,344 ) — Less: Undistributed income attributable to convertible preferred stockholders (1,281 ) — (3,212 ) Add: Undistributed loss attributable to convertible preferred stockholders — 3,266 — Net income (loss) attributable to common stockholders—basic and diluted $ 1,084 $ (833 ) $ 887 Denominator Weighted average shares used to compute net income (loss) attributable to common stockholders—Basic 11,993,429 4,609,375 4,304,396 Potential dilutive options, as calculated using treasury stock method 1,959,226 — 2,021,394 Potential dilutive common stock warrants, as calculated using treasury stock method — — 86,985 Potential dilutive restricted stock, as calculated using treasury stock method 266,995 — 88,060 Weighted average shares used to compute net income (loss) attributable to common stockholders—Diluted 14,219,650 4,609,375 6,500,835 Net income (loss) per share attributable to common stockholders —Basic $ 0.09 $ (0.18 ) $ 0.21 —Diluted $ 0.08 $ (0.18 ) $ 0.14
Schedule of Antidilutive Securities Excluded from Computation of Earnings per Share	The following outstanding shares of potentially dilutive securities were excluded from the computation of diluted net income (loss) per share of common stock for the periods presented, because the effect of including them would have been anti-dilutive: Year Ended December 31, 2015 2014 2013 Options to purchase common stock 1,321,250 2,933,757 63,750 Restricted stock and restricted stock units 96,800 367,126 — Total 1,418,050 3,300,883 63,750

Geographic Areas and Product 36

Geographic Areas and Product Sales Geographic Areas and Product Sales (Tables)	12 Months Ended
	Dec. 31, 2015
Segment Reporting [Abstract]
Revenue by Geographic Area	The Company’s revenue by geographic area, based on the destination to which the Company ships its products, was as follows (in thousands): Year Ended December 31, 2015 2014 2013 United States $ 127,311 $ 82,965 $ 58,305 Japan 19,016 14,699 12,668 Other International 39,768 27,846 17,875 Total $ 186,095 $ 125,510 $ 88,848
Revenue by Product Category	The following table sets forth revenue by product category (in thousands): Year Ended December 31, 2015 2014 2013 Neuro $ 141,410 $ 106,242 $ 81,343 Peripheral Vascular 44,685 19,268 7,505 Total $ 186,095 $ 125,510 $ 88,848

Selected Quarterly Financial 37

Selected Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information	The following table provides the selected quarterly financial data for 2015 and 2014 (in thousands, except share and per share amounts): Quarter Ended 2015 2014 December 31 September 30 June 30 March 31 December 31 September 30 June 30 March 31 Revenue $ 54,416 $ 50,416 $ 42,311 $ 38,952 $ 35,403 $ 32,464 $ 31,480 $ 26,163 Cost of revenue 17,958 16,919 14,936 12,224 11,512 11,667 10,780 8,709 Gross profit $ 36,458 $ 33,497 $ 27,375 $ 26,728 $ 23,891 $ 20,797 $ 20,700 $ 17,454 Income (loss) before provision for (benefit from) income taxes $ 1,876 $ 2,084 $ (4,178 ) $ 4,242 $ 417 $ 399 $ 526 $ 1,797 Net income (loss) $ 1,633 $ 901 $ (2,671 ) $ 2,502 $ 416 $ 172 $ 391 $ 1,266 Net income (loss) attributable to common stockholders $ 1,633 $ 276 $ (553 ) $ 503 $ 81 $ (1,192 ) $ 81 $ 280 Net income (loss) per share attributable to common stockholders—Basic $ 0.05 $ 0.04 $ (0.11 ) $ 0.10 $ 0.02 $ (0.25 ) $ 0.02 $ 0.06 Net income (loss) per share attributable to common stockholders—Diluted $ 0.05 $ 0.03 $ (0.11 ) $ 0.07 $ 0.01 $ (0.25 ) $ 0.01 $ 0.04 Weighted average shares used to compute net income (loss) per share attributable to common stockholders—Basic 29,890,944 7,853,730 5,096,151 4,903,535 4,701,999 4,688,045 4,608,510 4,430,824 Weighted average shares used to compute net income (loss) per share attributable to common stockholders—Diluted 32,321,410 10,189,248 5,096,151 7,193,452 7,102,885 4,688,045 6,868,889 6,705,066

Organization and Description 38

Organization and Description of Business (Details)	12 Months Ended
	Dec. 31, 2015market
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of major markets	2

Summary of Significant Accoun39

Summary of Significant Accounting Policies - Additional Disclosures (Details)	Sep. 23, 2015	Dec. 31, 2015USD ($)segmentactivity	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)
Accounting Policies [Abstract]
Number of business activities | activity		1
Number of operating segments | segment		1
Foreign currency transaction gains (losses)		$ (100,000)	$ (300,000)	$ (300,000)
Other-than-temporary impairments for marketable investments		0	0	0
Inventory write downs		1,163,000	1,852,000	892,000
Impairment of long-lived assets		0	0	0
Preferred stock conversion to common stock, conversion ratio	1
Deferred revenue		600,000	1,600,000
Advertising expense		$ 500,000	$ 300,000	$ 100,000

Summary of Significant Accoun40

Summary of Significant Accounting Policies - Concentration of Credit Risk (Details) $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)customerfinancial_instituion	Dec. 31, 2014USD ($)customer	Dec. 31, 2013customer
Customer Concentration Risk | Revenue | One Major Customer
Concentration Risk [Line Items]
Concentration risk number of customers that accounted for greater than specified benchmark	1	1	1
Concentration risk, percentage	10.00%	12.00%	14.00%
Customer Concentration Risk | Accounts Receivable
Concentration Risk [Line Items]
Concentration risk number of customers that accounted for greater than specified benchmark	0	0
Concentration risk, percentage	10.00%
Customer Concentration Risk | Accounts Receivable | One Major Customer
Concentration Risk [Line Items]
Concentration risk, percentage		10.00%
United States
Concentration Risk [Line Items]
Number of financial institutions holding cash in excess of federally insured limits | financial_instituion	1
Foreign Countries
Concentration Risk [Line Items]
Cash that is not federally insured | $	$ 1.9	$ 0.8

Summary of Significant Accoun41

Summary of Significant Accounting Policies - Property and Equipment, Net (Details)	12 Months Ended
	Dec. 31, 2015
Property and equipment excluding leasehold improvements
Property, Plant and Equipment [Line Items]
Useful life of property and equipment	5 years

Initial Public Offering (IPO) (

Initial Public Offering (IPO) (Details) $ / shares in Units, $ in Thousands	Sep. 23, 2015USD ($)$ / sharesshares	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)
Class of Stock [Line Items]
Proceeds from issuance of common stock issued in initial public offering, net of issuance costs		$ 124,742	$ 0	$ 0
Preferred stock conversion to common stock, number of shares | shares	19,510,410
Preferred stock conversion to common stock, conversion ratio	1
Initial Public Offering
Class of Stock [Line Items]
Shares issued, shares | shares	4,600,000
Shares issued, price per share (in dollars per share) | $ / shares	$ 30
Proceeds from issuance of common stock issued in initial public offering, net of issuance costs	$ 124,700
Payments for underwriting discounts and commissions	9,700
Payments for other offering expenses	$ 3,600

Fair Value of Financial Instr43

Fair Value of Financial Instruments (Details) - Recurring - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Financial Assets
Total	$ 139,359	$ 48,408
Commercial paper
Financial Assets
Marketable investments	22,332
Mutual funds
Financial Assets
Marketable investments		8,619
U.S. Treasury
Financial Assets
Marketable investments	15,436	4,009
U.S. Agency securities
Financial Assets
Marketable investments	21,464	6,006
U.S. States and Municipalities
Financial Assets
Marketable investments	2,084
Corporate bonds
Financial Assets
Marketable investments	61,002	29,619
Non-U.S. Government debt securities
Financial Assets
Marketable investments	6,939
Commercial paper
Financial Assets
Cash Equivalents	9,850
Money market funds
Financial Assets
Cash Equivalents	252	155
Level 1
Financial Assets
Total	15,688	12,783
Level 1 | Commercial paper
Financial Assets
Marketable investments	0
Level 1 | Mutual funds
Financial Assets
Marketable investments		8,619
Level 1 | U.S. Treasury
Financial Assets
Marketable investments	15,436	4,009
Level 1 | U.S. Agency securities
Financial Assets
Marketable investments	0	0
Level 1 | U.S. States and Municipalities
Financial Assets
Marketable investments	0
Level 1 | Corporate bonds
Financial Assets
Marketable investments	0	0
Level 1 | Non-U.S. Government debt securities
Financial Assets
Marketable investments	0
Level 1 | Commercial paper
Financial Assets
Cash Equivalents	0
Level 1 | Money market funds
Financial Assets
Cash Equivalents	252	155
Level 2
Financial Assets
Total	123,671	35,625
Level 2 | Commercial paper
Financial Assets
Marketable investments	22,332
Level 2 | Mutual funds
Financial Assets
Marketable investments		0
Level 2 | U.S. Treasury
Financial Assets
Marketable investments	0	0
Level 2 | U.S. Agency securities
Financial Assets
Marketable investments	21,464	6,006
Level 2 | U.S. States and Municipalities
Financial Assets
Marketable investments	2,084
Level 2 | Corporate bonds
Financial Assets
Marketable investments	61,002	29,619
Level 2 | Non-U.S. Government debt securities
Financial Assets
Marketable investments	6,939
Level 2 | Commercial paper
Financial Assets
Cash Equivalents	9,850
Level 2 | Money market funds
Financial Assets
Cash Equivalents	0	0
Level 3
Financial Assets
Total	0	0
Level 3 | Commercial paper
Financial Assets
Marketable investments	0
Level 3 | Mutual funds
Financial Assets
Marketable investments		0
Level 3 | U.S. Treasury
Financial Assets
Marketable investments	0	0
Level 3 | U.S. Agency securities
Financial Assets
Marketable investments	0	0
Level 3 | U.S. States and Municipalities
Financial Assets
Marketable investments	0
Level 3 | Corporate bonds
Financial Assets
Marketable investments	0	0
Level 3 | Non-U.S. Government debt securities
Financial Assets
Marketable investments	0
Level 3 | Commercial paper
Financial Assets
Cash Equivalents	0
Level 3 | Money market funds
Financial Assets
Cash Equivalents	$ 0	$ 0

Balance Sheet Components - Acco

Balance Sheet Components - Accounts Receivable, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance At Beginning Of Year	$ 602	$ 471	$ 212
Charged To Costs And Expenses	(13)	150	259
Deductions	0	(19)	0
Balance At End Of Year	$ 589	$ 602	$ 471

Balance Sheet Components - Prep

Balance Sheet Components - Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Prepaid expenses	$ 7,442	$ 3,130
Income tax receivable	606	1,654
Other current assets	1,304	331
Prepaid expenses and other current assets	$ 9,352	$ 5,115

Balance Sheet Components - Gain

Balance Sheet Components - Gains and Losses of Marketable Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Cost	$ 129,512	$ 48,625
Gross Unrealized Gains	14	7
Gross Unrealized Losses	(269)	(379)
Fair Value	129,257	48,253
Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Cost	22,328
Gross Unrealized Gains	5
Gross Unrealized Losses	(1)
Fair Value	22,332
U.S. Treasury
Schedule of Available-for-sale Securities [Line Items]
Cost	15,459	4,011
Gross Unrealized Gains	4	0
Gross Unrealized Losses	(27)	(2)
Fair Value	15,436	4,009
U.S. Agency securities
Schedule of Available-for-sale Securities [Line Items]
Cost	21,497	6,012
Gross Unrealized Gains	1	3
Gross Unrealized Losses	(34)	(9)
Fair Value	21,464	6,006
U.S. States and Municipalities
Schedule of Available-for-sale Securities [Line Items]
Cost	2,086
Gross Unrealized Gains	0
Gross Unrealized Losses	(2)
Fair Value	2,084
Corporate bonds
Schedule of Available-for-sale Securities [Line Items]
Cost	61,188	29,834
Gross Unrealized Gains	3	4
Gross Unrealized Losses	(189)	(219)
Fair Value	61,002	29,619
Non-U.S. Government debt securities
Schedule of Available-for-sale Securities [Line Items]
Cost	6,954
Gross Unrealized Gains	1
Gross Unrealized Losses	(16)
Fair Value	$ 6,939
Mutual funds
Schedule of Available-for-sale Securities [Line Items]
Cost		8,768
Gross Unrealized Gains		0
Gross Unrealized Losses		(149)
Fair Value		$ 8,619

Balance Sheet Components - Mark

Balance Sheet Components - Marketable Securities in an Unrealized Loss Position (Details) - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Fair Value	$ 97,802,000	$ 43,515,000
Gross Unrealized Losses, less than 12 months	(269,000)	(379,000)
Gross Unrealized Losses, greater than 12 months	0	0
Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Fair Value	4,746,000
Gross Unrealized Losses, less than 12 months	(1,000)
Mutual funds
Schedule of Available-for-sale Securities [Line Items]
Fair Value		8,619,000
Gross Unrealized Losses, less than 12 months		(149,000)
U.S. Treasury
Schedule of Available-for-sale Securities [Line Items]
Fair Value	12,453,000	3,008,000
Gross Unrealized Losses, less than 12 months	(27,000)	(2,000)
U.S. Agency securities
Schedule of Available-for-sale Securities [Line Items]
Fair Value	13,475,000	5,255,000
Gross Unrealized Losses, less than 12 months	(34,000)	(9,000)
U.S. States and Municipalities
Schedule of Available-for-sale Securities [Line Items]
Fair Value	2,084,000
Gross Unrealized Losses, less than 12 months	(2,000)
Corporate bonds
Schedule of Available-for-sale Securities [Line Items]
Fair Value	59,163,000	26,633,000
Gross Unrealized Losses, less than 12 months	(189,000)	$ (219,000)
Non-U.S. Government debt securities
Schedule of Available-for-sale Securities [Line Items]
Fair Value	5,881,000
Gross Unrealized Losses, less than 12 months	$ (16,000)

Balance Sheet Components - Cont

Balance Sheet Components - Contractual Maturities of Marketable Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Due in one year	$ 62,983	$ 16,442
Due in one to five years	66,274	31,811
Total	$ 129,257	$ 48,253

Balance Sheet Components - Inve

Balance Sheet Components - Inventories (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Raw materials	$ 9,176	$ 5,105
Work in process	2,746	543
Finished goods	44,839	27,803
Inventories	$ 56,761	$ 33,451

Balance Sheet Components - Prop

Balance Sheet Components - Property and Equipment, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 14,022	$ 8,670
Less: Accumulated depreciation and amortization	(5,071)	(3,489)
Property and equipment, net	8,951	5,181
Depreciation and amortization expense	1,752	751	$ 677
Machinery and equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	8,559	5,089
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Total property and equipment	2,091	519
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total property and equipment	1,564	379
Software
Property, Plant and Equipment [Line Items]
Total property and equipment	666	599
Computers
Property, Plant and Equipment [Line Items]
Total property and equipment	565	153
Construction in progress
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 577	$ 1,931

Balance Sheet Components - Accr

Balance Sheet Components - Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Payroll and employee-related expenses	$ 13,653	$ 8,221
Sales return reserve	3,247	2,164
Preclinical and clinical trial cost	1,330	2,319
Deferred revenue	526	1,591
Product warranty	713	314
Sales tax payable	531	306
Income tax payable	308	332
Other accrued liabilities	5,273	3,228
Total accrued liabilities	$ 25,581	$ 18,475

Balance Sheet Components - Prod

Balance Sheet Components - Product Warranty (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Product Warranty, Increase (Decrease) [Roll Forward]
Balance at the beginning of the year	$ 314	$ 323	$ 323
Accruals of warranties issued	752	149	100
Settlements of warranty claims	(353)	(158)	(100)
Balance at the end of the year	$ 713	$ 314	$ 323

Credit Facility (Details)

Credit Facility (Details) - Revolving credit facility - Wells Fargo Bank, National Association	1 Months Ended
	May. 31, 2012USD ($)
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 15,000,000
One-month London Inter-Bank Offered Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.75%

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($)	1 Months Ended		12 Months Ended
	Jul. 31, 2011	Mar. 31, 2005	Dec. 31, 2015	Dec. 31, 2014
Related Party Transaction [Line Items]
Exercised (shares)			948,872
Promissory notes receivable			$ 5,000	$ 117,000
Stockholders
Related Party Transaction [Line Items]
Promissory notes receivable			$ 4,600	$ 100,000
Stockholders | March 2005 Transaction
Related Party Transaction [Line Items]
Exercised (shares)		250,000
Promissory notes receivable		$ 21,250
Interest rate on promissory notes		2.92%
Stockholders | July 2011 Transaction
Related Party Transaction [Line Items]
Exercised (shares)	5,000
Promissory notes receivable	$ 4,600

Commitments and Contingencies -

Commitments and Contingencies - Lease and Purchase Commitments (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Dec. 31, 2015USD ($)ft²	Dec. 31, 2015USD ($)ft²lease_term	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)
Operating Leases [Line Items]
Rent expense		$ 3,200	$ 1,800	$ 1,700
Future minimum lease payments under non-cancelable operating leases
2,016	$ 4,055	4,055
2,017	4,861	4,861
2,018	4,877	4,877
2,019	5,007	5,007
2,020	5,133	5,133
Thereafter	52,555	52,555
Total future minimum lease payments	76,488	76,488
Purchase obligations	$ 11,800	$ 11,800
Headquarters, Additional Lease
Operating Leases [Line Items]
Rentable area (in sqft) | ft²	99,968	99,968
Additional rentable area available (in sqft) | ft²	15,882	15,882
Term of lease contract under which additional area can be added to lease at current rate		10 years
Term of lease contract	15 years
Maximum number of renewal terms | lease_term		3
Renewal term		5 years
Headquarters, Additional Lease | Maximum
Operating Leases [Line Items]
Rentable area (in sqft) | ft²	117,325	117,325

Commitments and Contingencies56

Commitments and Contingencies - Royalty Obligations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cost of Sales
Other Commitments [Line Items]
Royalty expense	$ 2	$ 1.1	$ 0.7
Royalty Agreement, March 2005
Other Commitments [Line Items]
Minimum annual royalty payments	$ 0.1	$ 0.1
Term of royalty agreement	15 years
Royalty Agreement, April 2012
Other Commitments [Line Items]
Term of royalty agreement	15 years
Royalty as a percent of sales	5.00%
Royalty Agreement, April 2015
Other Commitments [Line Items]
Term of royalty agreement	20 years
Royalty as a percent of sales	2.00%

Commitments and Contingencies57

Commitments and Contingencies - Litigation (Details) $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)
Damages from Product
Loss Contingencies [Line Items]
Damages sought, value	$ 35

Convertible Preferred Stock (De

Convertible Preferred Stock (Details) $ in Thousands	Sep. 23, 2015shares	Dec. 31, 2015USD ($)shares	Dec. 31, 2014USD ($)shares
Temporary Equity [Line Items]
Shares Authorized		0	25,000,000
Shares issued		0	19,510,410
Shares outstanding		0	19,510,410
Proceeds, Net of Issuance Costs | $		$ 0	$ 111,467
Aggregate Liquidation Amount | $			$ 149,361
Preferred stock conversion to common stock, number of shares	19,510,410
Preferred stock conversion to common stock, conversion ratio	1
Series A Preferred Stock
Temporary Equity [Line Items]
Shares Authorized			1,000,000
Shares issued			1,000,000
Shares outstanding			1,000,000
Proceeds, Net of Issuance Costs | $			$ 299
Aggregate Liquidation Amount | $			$ 554
Series B Preferred Stock
Temporary Equity [Line Items]
Shares Authorized			4,287,486
Shares issued			4,005,338
Shares outstanding			4,005,338
Proceeds, Net of Issuance Costs | $			$ 6,536
Aggregate Liquidation Amount | $			$ 11,725
Series C Preferred Stock
Temporary Equity [Line Items]
Shares Authorized			4,388,715
Shares issued			4,168,218
Shares outstanding			4,168,218
Proceeds, Net of Issuance Costs | $			$ 13,266
Aggregate Liquidation Amount | $			$ 22,238
Series D Preferred Stock
Temporary Equity [Line Items]
Shares Authorized			3,944,733
Shares issued			3,881,459
Shares outstanding			3,881,459
Proceeds, Net of Issuance Costs | $			$ 19,647
Aggregate Liquidation Amount | $			$ 30,976
Series E Preferred Stock
Temporary Equity [Line Items]
Shares Authorized			1,973,684
Shares issued			1,909,940
Shares outstanding			1,909,940
Proceeds, Net of Issuance Costs | $			$ 14,507
Aggregate Liquidation Amount | $			$ 21,609
Series F Preferred Stock
Temporary Equity [Line Items]
Shares Authorized			5,303,031
Shares issued			4,545,455
Shares outstanding			4,545,455
Proceeds, Net of Issuance Costs | $			$ 57,212
Aggregate Liquidation Amount | $			$ 62,259
Undesignated
Temporary Equity [Line Items]
Shares Authorized			4,102,351
Shares issued			0
Shares outstanding			0
Proceeds, Net of Issuance Costs | $			$ 0
Aggregate Liquidation Amount | $			$ 0

Common Stock (Details)

Common Stock (Details)	12 Months Ended
	Dec. 31, 2015vote
Equity [Abstract]
Common stock, number of votes per share	1

Warrants (Details)

Warrants (Details) - $ / shares	12 Months Ended
	Dec. 31, 2004	Dec. 31, 2015	Dec. 31, 2014
Equity [Abstract]
Number of shares of common stock called by warrants	211,138
Purchase price of common stock (in dollars per share)	$ 0.01
Term of warrants	10 years
Warrants outstanding		0	0

Stock Option Plans - Stock Plan

Stock Option Plans - Stock Plans (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Sep. 17, 2015	Jul. 31, 2015	Jun. 30, 2015	Mar. 31, 2015	Sep. 30, 2014	May. 16, 2014	Oct. 01, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options outstanding (shares)	3,755,345	2,900,676
Number of options unvested and subject to repurchase (shares)	12,339	33,081
Liability relating to cash received from employees for exercise of unvested options	$ 100,000	$ 200,000
Common stock, fair value determined using option pricing method (in dollars per share)								$ 10.92	$ 9.06	$ 7.75
Common stock, fair value determined using probability weighted expected return method		$ 12.36			$ 22.04	$ 20.51	$ 14.46
Intrinsic value of options exercised in period	$ 13,100,000	$ 3,800,000	$ 300,000
Weighted average grant date fair value (in dollars per share)	$ 9.69	$ 3.69	$ 2.63
Unrecognized compensation cost related to unvested share-based compensation arrangements	$ 27,200,000
Unrecognized compensation cost, expected recognition period	2 years 1 month
Share-based compensation expense capitalized in inventory	$ 300,000
Restricted stock and restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of awards outstanding (shares)	849,571	367,126
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock reserved for future issuance (shares)				600,000
Minimum percent of eligible compensation per pay period to be used to purchase shares under plan	1.00%
Maximum percent of eligible compensation per pay period to be used to purchase shares under plan	15.00%
Purchase price of common stock, percent of fair market value	85.00%
Maximum number of shares that may be purchased by any one employee	2,000
Maximum value of shares that may be purchased by any one employee	$ 25,000
2005 Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted since inception of plan (shares)	5,431,017	5,431,017
Number of options outstanding (shares)	1,757,282	2,707,176
Number of options unvested and subject to repurchase (shares)	12,339	33,081
2005 Stock Plan | Stock Options | Vesting, First Year
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rate	25.00%
2005 Stock Plan | Stock Options | Vesting, After First Year, Monthly Vesting Rate
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rate	2.08%
2005 Stock Plan | Incentive Stock Options (ISO)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Minimum voting rights for determination of exercise price, percent	10.00%
Minimum exercise price, percent over fair market value	110.00%
2005 Stock Plan | Incentive Stock Options (ISO) | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Term of award	5 years
2005 Stock Plan | Other Options | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Term of award	10 years
2011 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted since inception of plan (shares)	145,000	145,000
Number of options outstanding (shares)	145,000	145,000
2011 Equity Incentive Plan | Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Term of award	10 years
Award vesting period	4 years
2011 Equity Incentive Plan | Incentive Stock Options (ISO)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Minimum voting rights for determination of exercise price, percent	10.00%
Minimum exercise price, percent over fair market value	110.00%
2011 Equity Incentive Plan | Restricted stock and restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted since inception of plan (shares)	505,000	505,000
Number of awards outstanding (shares)	249,125	367,126
Awards forfeited since inception of plan (shares)	4,667	1,667
2014 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted since inception of plan (shares)	1,857,900	48,500
Number of options outstanding (shares)	1,853,063	48,500
Shares of common stock reserved for future issuance (shares)	3,000,000
Number of shares available for grant	597,730
Options forfeited since inception of plan (shares)	4,421	1,000
2014 Equity Incentive Plan | Restricted stock and restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted since inception of plan (shares)	673,361	0
Number of awards outstanding (shares)	508,646	0
2014 Equity Incentive Plan | RSU
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted since inception of plan (shares)	91,800	0
Number of awards outstanding (shares)	91,800	0

Stock Option Plans - Stock Opti

Stock Option Plans - Stock Option Activity (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015USD ($)$ / sharesshares
Number of Shares
Beginning balance (shares) | shares	2,900,676
Granted (shares) | shares	1,809,400
Exercised (shares) | shares	(948,872)
Cancelled/Forfeited (in dollars per share) | shares	(5,859)
Ending balance (shares) | shares	3,755,345
Weighted Average Exercise Price
Beginning balance (in dollars per share) | $ / shares	$ 2.66
Granted (in dollars per share) | $ / shares	21.47
Exercised (in dollars per share) | $ / shares	0.99
Cancelled/Forfeited (in dollars per share) | $ / shares	11.15
Ending balance (in dollars per share) | $ / shares	$ 12.13
Options Vested and Expected to Vest
Number of Shares | shares	3,621,919
Weighted Average Exercise Price | $ / shares	$ 11.79
Weighted Average Remaining Contractual Life (in Years)	6 years 8 months 12 days
Aggregate Intrinsic Value (in thousands) | $	$ 152,187
Options Exercisable
Number of Shares | shares	1,941,150
Weighted Average Exercise Price | $ / shares	$ 3.47
Weighted Average Remaining Contractual Life (in Years)	4 years 2 months 12 days
Aggregate Intrinsic Value (in thousands) | $	$ 97,717

Stock Option Plans - Stock Op63

Stock Option Plans - Stock Options Assumptions (Details)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)		6 years 3 months	6 years 3 months
Expected volatility	45.00%	45.00%	45.00%
Risk-free interest rate, minimum	1.56%	1.76%	0.63%
Risk-free interest rate, maximum	1.78%	2.02%	0.90%
Expected dividend rate	0.00%	0.00%	0.00%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	6 years 29 days
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	6 years 3 months

Stock Option Plans - Restricted

Stock Option Plans - Restricted Stock Activity (Details) - Restricted stock and restricted stock units	12 Months Ended
	Dec. 31, 2015$ / sharesshares
Number of Shares
Unvested beginning balance (shares) | shares	367,126
Granted (shares) | shares	765,161
Vested (shares) | shares	(279,716)
Cancelled/Forfeited (shares) | shares	(3,000)
Unvested and expected to vest ending balance (shares) | shares	849,571
Weighted Average Grant Date Fair Value
Unvested beginning balance (in dollars per share) | $ / shares	$ 7.26
Granted (in dollars per share) | $ / shares	17.70
Vested (in dollars per share) | $ / shares	11.93
Cancelled/Forfeited (in dollars per share) | $ / shares	7.75
Unvested and expected to vest ending balance (in dollars per share) | $ / shares	$ 15.12

Stock Option Plans - Stock-base

Stock Option Plans - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 7,271	$ 1,433	$ 886
Cost of sales
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	316	267	98
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	444	96	84
Sales, general and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 6,511	$ 1,070	$ 704

Common and Preferred Stock Re66

Common and Preferred Stock Repurchase (Details) - USD ($)	1 Months Ended		2 Months Ended	12 Months Ended
	Jul. 31, 2014	May. 31, 2014	Jun. 30, 2014	Dec. 31, 2015	Dec. 31, 2014
Class of Stock [Line Items]
Share repurchase program, price per share (in dollars per share)		$ 13.20
Value of shares authorized to be repurchased		$ 2,000,000
Value of shares repurchased and retired				$ 342,000	$ 1,040,000
Stock Options
Class of Stock [Line Items]
Number of shares authorized to be repurchased		45,000
Common Stock
Class of Stock [Line Items]
Number of shares authorized to be repurchased		70,612
Shares repurchased and retired				23,650	115,612
Common Stock | Stock Options
Class of Stock [Line Items]
Excess between the purchase and issuance price			$ 500,000
Preferred Stock
Class of Stock [Line Items]
Number of shares authorized to be repurchased		45,611
Share repurchase program, price per share (in dollars per share)	$ 13.20
Excess between the purchase and issuance price	$ 5,800,000		$ 500,000
Shares repurchased and retired	584,052
Value of shares repurchased and retired	$ 7,700,000

Accumulated Other Comprehensi67

Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ (12,370)	$ (8,062)
Other comprehensive income before reclassifications:
Income tax effect—benefit (expense)	245	406
Net of tax	(1,597)	(1,650)
Amounts reclassified from accumulated other comprehensive income to earnings:
Realized losses—marketable investments	540	(17)
Income tax effect—benefit	(194)	7
Net of tax	346	(10)
Net current-year other comprehensive income (loss)	(1,251)	(1,660)
Ending balance	232,522	(12,370)
Marketable Investments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(220)	17
Other comprehensive income before reclassifications:
OCI, before reclassifications, before tax, attributable to parent	(417)	(388)
Income tax effect—benefit (expense)	128	161
Net of tax	(289)	(227)
Amounts reclassified from accumulated other comprehensive income to earnings:
Realized losses—marketable investments	540	(17)
Income tax effect—benefit	(194)	7
Net of tax	346	(10)
Net current-year other comprehensive income (loss)	57	(237)
Ending balance	(163)	(220)
Currency Translation Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(644)	779
Other comprehensive income before reclassifications:
OCI, before reclassifications, before tax, attributable to parent	(1,425)	(1,668)
Income tax effect—benefit (expense)	117	245
Net of tax	(1,308)	(1,423)
Amounts reclassified from accumulated other comprehensive income to earnings:
Realized losses—marketable investments	0	0
Income tax effect—benefit	0	0
Net of tax	0	0
Net current-year other comprehensive income (loss)	(1,308)	(1,423)
Ending balance	(1,952)	(644)
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(864)	796
Amounts reclassified from accumulated other comprehensive income to earnings:
Ending balance	$ (2,115)	$ (864)

Employee Benefit Plans Narrativ

Employee Benefit Plans Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)
Compensation and Retirement Disclosure [Abstract]
Employer contribution cost	$ 0.3

Income Taxes - Income (Loss) be

Income Taxes - Income (Loss) before Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
United States									$ 2,955	$ 2,230	$ (1,142)
Foreign									1,069	909	(113)
Income (loss) before provision for (benefit from) income taxes	$ 1,876	$ 2,084	$ (4,178)	$ 4,242	$ 417	$ 399	$ 526	$ 1,797	$ 4,024	$ 3,139	$ (1,255)

Income Taxes - Provision for (B

Income Taxes - Provision for (Benefit from) for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current:
Federal	$ 3,815	$ 1,155	$ (155)
State	603	274	87
Foreign	492	323	0
Total current	4,910	1,752	(68)
Deferred:
Federal	(3,025)	(625)	(5,087)
State	(251)	(116)	(199)
Foreign	25	(117)	0
Total deferred	(3,251)	(858)	(5,286)
Provision for (benefit from) income taxes	$ 1,659	$ 894	$ (5,354)

Income Taxes - Effective Income

Income Taxes - Effective Income Tax Reconciliation (Details)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Income tax at federal statutory rate	34.00%	34.00%	34.00%
State income taxes, net of federal benefit	1.90%	3.20%	(5.60%)
Foreign taxes differential	(9.00%)	5.20%	5.80%
Prepaid tax ASC 810-10	2.10%	(8.90%)	(2.70%)
Foreign exchange gains and losses	0.00%	0.00%	11.70%
IRC 199 deduction	(7.40%)	(7.00%)	(0.00%)
Stock-based compensation	14.80%	6.00%	(14.10%)
Meals and entertainment	5.60%	5.80%	(10.70%)
Imputed interest	4.70%	6.60%	(12.10%)
Tax credits	(11.60%)	(12.10%)	41.80%
Other	3.60%	2.80%	0.30%
Change in valuation allowance	2.50%	(7.10%)	378.20%
Effective tax rate	41.20%	28.50%	426.60%

Income Taxes - Deferred Tax Ass

Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2015	Dec. 31, 2012
Deferred tax assets
Net operating loss carryforwards	$ 1,626		$ 1,000
Tax credits	1,779		1,355
Accruals and reserves	3,759		5,048
Stock-based compensation	416		1,352
Translation adjustment	674		715
UNICAP adjustments	2,227		3,840
Other	0		870
Gross deferred tax assets	10,481		14,180
Valuation allowance	(2,945)	$ (3,860)	(2,702)	$ (8,742)
Total deferred tax assets	7,536		11,478
Deferred tax liabilities
Depreciation and amortization	(685)		(1,335)
Total deferred tax liabilities	(685)		(1,335)
Net deferred tax assets	6,851		10,143
Deferred income taxes, net - Balance Sheet Classification
Current deferred income tax assets	6,280		0
Long-term deferred income tax assets	571		$ 10,143
Internal Revenue Service and State Tax Authorities
Income Tax Examination [Line Items]
Decrease in valuation allowance		$ 5,000
Germany | Foreign
Income Tax Examination [Line Items]
Decrease in valuation allowance	$ 300

Income Taxes - Valuation Allowa

Income Taxes - Valuation Allowance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reconciliation of valuation allowance
Beginning balance	$ 2,945	$ 3,860	$ 8,742
Release of valuation allowance	(243)	(321)	(4,962)
Other reserves and deferrals	0	(594)	80
Ending balance	$ 2,702	$ 2,945	$ 3,860

Income Taxes - Operating Loss C

Income Taxes - Operating Loss Carryforwards (Details) $ in Millions	Dec. 31, 2015USD ($)
State
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 16.3
Operating loss carryforwards, stock based compensation	0.6
Foreign
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 1.8

Income Taxes - Tax Credit Carry

Income Taxes - Tax Credit Carryforwards (Details) $ in Millions	Dec. 31, 2015USD ($)
Research Tax Credit | State
Tax Credit Carryforward [Line Items]
Tax credit carryforwards	$ 3.6

Income Taxes - Unrecognized Tax

Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Unrecognized tax benefits	$ 1,726	$ 1,325	$ 838	$ 3,619
Unrecognized tax benefits that would affect the effective tax rate if recognized				1,300
Reconciliation of the change in gross unrecognized tax benefits
Beginning balance	1,726	1,325	838
Gross increase for tax positions of current year	1,023	401	324
Gross increase for tax positions of prior years	1,062	0	163
Settlements	0	0	0
Lapse of statute of limitations	(192)	0	0
Ending balance	$ 3,619	$ 1,726	$ 1,325
Accrued interest and penalties related to uncertain tax positions				$ 100

Net Income (Loss) per Share o77

Net Income (Loss) per Share of Common Stock attributable to Common Stockholders - Basic and Diluted Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Numerator
Net income	$ 1,633	$ 901	$ (2,671)	$ 2,502	$ 416	$ 172	$ 391	$ 1,266	$ 2,365	$ 2,245	$ 4,099
Less: Deemed dividend paid to convertible preferred stockholders upon repurchase									0	(6,344)	0
Undistributed (income) loss attributable to preferred stockholders, basic									(1,281)	3,266	(3,212)
Net income (loss) attributable to common stockholders, basic	$ 1,633	$ 276	$ (553)	$ 503	$ 81	$ (1,192)	$ 81	$ 280	1,084	(833)	887
Net income (loss) available to common stockholders, diluted									$ 1,084	$ (833)	$ 887
Denominator
Weighted average shares used to compute net income (loss) per share attributable to common stockholders—Basic (in shares)	29,890,944	7,853,730	5,096,151	4,903,535	4,701,999	4,688,045	4,608,510	4,430,824	11,993,429	4,609,375	4,304,396
Potential dilutive common stock warrants, as calculated using treasury stock method									0	0	86,985
Weighted average shares used to compute net income (loss) per share attributable to common stockholders—Diluted (in shares)	32,321,410	10,189,248	5,096,151	7,193,452	7,102,885	4,688,045	6,868,889	6,705,066	14,219,650	4,609,375	6,500,835
Net income (loss) per share attributable to common stockholders—Basic (in USD per share)	$ 0.05	$ 0.04	$ (0.11)	$ 0.10	$ 0.02	$ (0.25)	$ 0.02	$ 0.06	$ 0.09	$ (0.18)	$ 0.21
Net income (loss) per share attributable to common stockholders—Diluted (in USD per share)	$ 0.05	$ 0.03	$ (0.11)	$ 0.07	$ 0.01	$ (0.25)	$ 0.01	$ 0.04	$ 0.08	$ (0.18)	$ 0.14
Stock Options
Denominator
Potential dilutive common stock securities, as calculated using treasury stock method									1,959,226	0	2,021,394
Restricted stock and restricted stock units
Denominator
Potential dilutive common stock securities, as calculated using treasury stock method									266,995	0	88,060

Net Income (Loss) per Share o78

Net Income (Loss) per Share of Common Stock attributable to Common Stockholders - Antidilutive Securities (Details) - shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from the computation of earnings per share	1,418,050	3,300,883	63,750
Options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from the computation of earnings per share	1,321,250	2,933,757	63,750
Restricted stock and restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from the computation of earnings per share	96,800	367,126	0

Geographic Areas and Product 79

Geographic Areas and Product Sales - Revenue by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 54,416	$ 50,416	$ 42,311	$ 38,952	$ 35,403	$ 32,464	$ 31,480	$ 26,163	$ 186,095	$ 125,510	$ 88,848
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									127,311	82,965	58,305
Japan
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									19,016	14,699	12,668
Other International
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue									$ 39,768	$ 27,846	$ 17,875

Geographic Areas and Product 80

Geographic Areas and Product Sales - Revenue by Product Category (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenue from External Customer [Line Items]
Revenue	$ 54,416	$ 50,416	$ 42,311	$ 38,952	$ 35,403	$ 32,464	$ 31,480	$ 26,163	$ 186,095	$ 125,510	$ 88,848
Neuro
Revenue from External Customer [Line Items]
Revenue									141,410	106,242	81,343
Peripheral Vascular
Revenue from External Customer [Line Items]
Revenue									$ 44,685	$ 19,268	$ 7,505

Selected Quarterly Financial 81

Selected Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 54,416	$ 50,416	$ 42,311	$ 38,952	$ 35,403	$ 32,464	$ 31,480	$ 26,163	$ 186,095	$ 125,510	$ 88,848
Cost of revenue	17,958	16,919	14,936	12,224	11,512	11,667	10,780	8,709	62,037	42,668	30,972
Gross profit	36,458	33,497	27,375	26,728	23,891	20,797	20,700	17,454	124,058	82,842	57,876
Income (loss) before provision for (benefit from) income taxes	1,876	2,084	(4,178)	4,242	417	399	526	1,797	4,024	3,139	(1,255)
Net income	1,633	901	(2,671)	2,502	416	172	391	1,266	2,365	2,245	4,099
Net income (loss) attributable to common stockholders	$ 1,633	$ 276	$ (553)	$ 503	$ 81	$ (1,192)	$ 81	$ 280	$ 1,084	$ (833)	$ 887
Net income (loss) per share attributable to common stockholders—Basic (in USD per share)	$ 0.05	$ 0.04	$ (0.11)	$ 0.10	$ 0.02	$ (0.25)	$ 0.02	$ 0.06	$ 0.09	$ (0.18)	$ 0.21
Net income (loss) per share attributable to common stockholders—Diluted (in USD per share)	$ 0.05	$ 0.03	$ (0.11)	$ 0.07	$ 0.01	$ (0.25)	$ 0.01	$ 0.04	$ 0.08	$ (0.18)	$ 0.14
Weighted average shares used to compute net income (loss) per share attributable to common stockholders—Basic (in shares)	29,890,944	7,853,730	5,096,151	4,903,535	4,701,999	4,688,045	4,608,510	4,430,824	11,993,429	4,609,375	4,304,396
Weighted average shares used to compute net income (loss) per share attributable to common stockholders—Diluted (in shares)	32,321,410	10,189,248	5,096,151	7,193,452	7,102,885	4,688,045	6,868,889	6,705,066	14,219,650	4,609,375	6,500,835