Penumbra (PEN) 10-K 28 Feb 17 2016 FY Annual report Financial data

Document and Entity Information

Document and Entity Information Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2016	Jan. 31, 2017	Jun. 30, 2016
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	Large Accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		31,941,821
Entity Current Reporting Status	Yes
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Public Float			$ 1.5

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 13,236	$ 19,547
Marketable investments	115,517	129,257
Accounts receivable, net of doubtful accounts of $684 and $589 at December 31, 2016 and 2015, respectively	43,335	29,444
Inventories	73,012	56,761
Prepaid expenses and other current assets	18,727	9,352
Total current assets	263,827	244,361
Property and equipment, net	21,464	8,951
Deferred taxes	22,476	10,143
Other non-current assets	487	393
Total assets	308,254	263,848
Current liabilities:
Accounts payable	4,110	2,567
Accrued liabilities	31,690	25,581
Total current liabilities	35,800	28,148
Deferred Rent Credit, Noncurrent	5,083	1,511
Other non-current liabilities	824	1,667
Total liabilities	41,707	31,326
Commitments and contingencies (Note 7)
Stockholders’ equity:
Preferred stock, $0.001 par value per share—5,000,000 shares authorized, none issued and outstanding at December 31, 2016 and 2015	0	0
Common stock, $0.001 par value per share—300,000,000 shares authorized, 31,108,828 issued and outstanding at December 31, 2016; 300,000,000 shares authorized, 29,897,860 issued and outstanding at December 31, 2015	31	30
Additional paid-in capital	273,865	252,087
Notes receivable from stockholders	0	(5)
Accumulated other comprehensive loss	(4,688)	(2,115)
Accumulated deficit	(2,661)	(17,475)
Total stockholders’ equity	266,547	232,522
Total liabilities and stockholders’ equity	$ 308,254	$ 263,848

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 684	$ 589
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	300,000,000	300,000,000
Common stock, shares issued (in shares)	31,108,828	29,897,860
Common stock, shares outstanding (in shares)	31,108,828	29,897,860

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement [Abstract]
Revenue	$ 263,317	$ 186,095	$ 125,510
Cost of revenue	92,488	62,037	42,668
Gross profit	170,829	124,058	82,842
Operating expenses:
Research and development	23,875	18,027	15,575
Sales, general and administrative	148,304	101,852	64,258
Total operating expenses	172,179	119,879	79,833
(Loss) Income from operations	(1,350)	4,179	3,009
Interest income, net	2,323	541	439
Other expense, net	(1,842)	(696)	(309)
(Loss) Income before provision for (benefit from) income taxes	(869)	4,024	3,139
Provision for (benefit from) income taxes	(15,683)	1,659	894
Net income	14,814	2,365	2,245
Foreign currency translation adjustments, net of tax	(2,631)	(1,308)	(1,423)
Unrealized gains (losses) on available-for-sale securities, net of tax	58	57	(237)
Comprehensive income	12,241	1,114	585
Net (loss) income attributable to common stockholders	$ 14,814	$ 1,084	$ (833)
Net income (loss) per share attributable to common stockholders—Basic (in dollars per share)	$ 0.49	$ 0.09	$ (0.18)
Net income (loss) per share attributable to common stockholders—Diluted (in dollars per share)	$ 0.44	$ 0.08	$ (0.18)
Weighted average shares used to compute net income (loss) per share attributable to common stockholders—Basic (in shares)	30,464,583	11,993,429	4,609,375
Weighted average shares used to compute net income (loss) per share attributable to common stockholders—Diluted (in shares)	33,478,078	14,219,650	4,609,375

Consolidated Statements of Conv

Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Notes Receivable from Stockholders	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Increase (Decrease) in Temporary Equity [Roll Forward]
Repurchase of preferred stock	$ (6,344)					$ (6,344)
Beginning balance at Dec. 31, 2013	(8,062)	$ 4	$ 6,269	$ (138)	$ 796	(14,993)
Beginning balance (in shares) at Dec. 31, 2013		4,391,588
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common stock	(1,040)		(292)			(748)
Repurchase of common stock (in shares)		(115,612)
Issuance of common stock	1,037	$ 1	1,036
Issuance of common stock (in shares)		460,713
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 (in shares) at Dec. 31, 2014		4,736,689
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 (in shares)		19,510,410
Shares issued upon closing of IPO	124,742	$ 5	124,737
Shares issued upon closing of IPO (in shares)		4,600,000
Repurchase of common stock	(342)		(342)
Repurchase of common stock (in shares)		(23,650)
Issuance of common stock	1,126	$ 1	1,125
Issuance of common stock (in shares)		1,074,411
Stock-based compensation	7,608		7,608
Forgiven notes receivable from stockholders	91			91
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
Shares held for tax withholdings	(2,525)		(2,525)
Excess tax benefit from stock-based compensation	1,590		1,590
Note received from a stockholder	21			21
Ending balance at Dec. 31, 2015	232,522	$ 30	252,087	(5)	(2,115)	(17,475)
Ending balance (in shares) at Dec. 31, 2015		29,897,860
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,291
Ending balance at Mar. 31, 2016	238,048
Beginning balance at Dec. 31, 2015	232,522	$ 30	252,087	(5)	(2,115)	(17,475)
Beginning balance (in shares) at Dec. 31, 2015		29,897,860
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock	$ 3,168	$ 1	3,167
Issuance of common stock (in shares)		1,043,223
Issuance of common stock under employee stock purchase plan	214,025	214,025
Issuance of common stock under employee stock purchase plan	$ 6,578		6,578
Stock-based compensation	14,657		14,657
Foreign currency translation adjustment, net of tax	(2,631)				(2,631)
Unrealized gain (loss) on investments, net of tax	58				58
Net income	14,814					14,814
Shares held for tax withholdings	(2,624)		(2,624)
Note received from a stockholder	5			5
Ending balance at Dec. 31, 2016	266,547	$ 31	273,865	0	(4,688)	(2,661)
Ending balance (in shares) at Dec. 31, 2016		31,108,828
Beginning balance at Mar. 31, 2016	238,048
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	3,013
Ending balance at Jun. 30, 2016	247,556
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	11,906
Ending balance at Sep. 30, 2016	263,604
Ending balance at Dec. 31, 2016	$ 266,547	$ 31	$ 273,865	$ 0	$ (4,688)	$ (2,661)
Ending balance (in shares) at Dec. 31, 2016		31,108,828

Consolidated Statement of Conve

Consolidated Statement of Convertible Preferred Stock and Stockholders’ Equity (Deficit) (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Stockholders' Equity [Abstract]
Foreign currency translation adjustment, tax	$ (3)	$ 117	$ 245
Unrealized gain on investments, tax	$ (32)	$ 66	$ 168

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 14,814	$ 2,365	$ 2,245
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation and amortization	2,297	1,752	751
Amortization of premium on marketable investments	997	83	0
Stock-based compensation	14,637	7,271	1,433
Provision for doubtful accounts	216	(13)	150
Inventory write downs	2,667	1,163	1,852
Write off of note receivable	0	91	21
Loss on minority investment	0	0	150
Loss on disposal of property and equipment	143	43	21
Realized (gain) loss on marketable investments	(8)	541	0
Deferred taxes	(12,378)	(3,204)	(892)
Changes in operating assets and liabilities:
Accounts receivable	(14,560)	(11,063)	(7,426)
Inventories	(19,737)	(25,126)	(9,444)
Prepaid expenses and other current and non-current assets	(9,043)	(4,013)	(1,906)
Accounts payable	1,375	132	1,299
Accrued expenses and other non-current liabilities	5,773	9,289	5,357
Net cash used in operating activities	(12,807)	(20,689)	(6,389)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of marketable investments	(63,346)	(135,340)	(51,342)
Proceeds from sales of marketable investments	12,997	54,998	18,229
Proceeds from Maturities, Prepayments and Calls of Available-for-sale Securities	64,671	0	0
Purchases of property and equipment	(13,635)	(5,474)	(3,888)
Net cash provided by (used in) investing activities	687	(85,816)	(37,001)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of preferred stock, net of issuance costs	0	0	57,212
Proceeds from issuance of common stock issued in initial public offering, net of issuance costs	0	124,742	0
Proceeds from exercises of stock options	3,172	617	1,036
Proceeds from issuance of stock under employee stock purchase plan	6,578	0	0
Repurchase of preferred stock	0	0	(8,311)
Repayment of credit facility	0	0	(6,000)
Repurchase of common stock and stock options	0	0	(1,040)
Payment of employee taxes related to vested common and restricted stock	(2,624)	(2,525)	0
Net cash provided by financing activities	7,126	122,834	42,897
Effect of foreign exchange rate changes on cash and cash equivalents	(1,317)	(72)	(348)
NET (DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	(6,311)	16,257	(841)
CASH AND CASH EQUIVALENTS—Beginning of period	19,547	3,290	4,131
CASH AND CASH EQUIVALENTS—End of period	13,236	19,547	3,290
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Cash paid for interest	0	1	160
Cash paid for income taxes	2,149	1,220	3,086
NONCASH INVESTING AND FINANCING ACTIVITIES:
Conversion of convertible preferred stock into common stock	0	111,467	0
Purchase of property and equipment funded through accounts payable	$ 1,442	$ 143	$ 44

Organization and Description of

Organization and Description of Business	12 Months Ended
	Dec. 31, 2016
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 healthcare company focused on interventional therapies. The Company designs, develops, manufactures and markets innovative devices and 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, 2016
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 generally accepted accounting principles in the United States (U.S. GAAP). Certain changes in presentation were made in the consolidated financial statements for the year ended December 31, 2015 and 2014 , to conform to the presentation for the year ended December 31, 2016 . 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 consolidated operating results for the purpose of allocating resources and evaluating financial performance. 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 loss 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 expense, net in the consolidated statements of operations and comprehensive income. The Company recognized net foreign currency transaction losses of $0.7 million , $0.1 million and $0.3 million during the years ended December 31, 2016 , 2015 and 2014 , 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. 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, 2016 and held cash in foreign banks of approximately $2.1 million and $1.9 million at December 31, 2016 and 2015 , respectively, which was not federally insured. The Company’s revenue has been derived from sales of its products in the United States 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, 2016 , 2015 and 2014 , one customer (a distributor) accounted for 11.5% , 10% and 12% , respectively, of the Company’s revenue. No customer accounted for greater than 10% of the Company’s accounts receivable balance as of December 31, 2016 or 2015 . 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 FDA prior to commencing commercial sales in the United States . 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, 2016 , 2015 or 2014 . 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 $2.7 million , $1.2 million and $1.9 million for the years ended December 31, 2016 , 2015 and 2014 , respectively. Property and Equipment, net Property and equipment are stated at cost less accumulated depreciation. Depreciation is computed using the straight-line method over 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. Machinery and equipment and furniture and fixtures are depreciated over a five to ten year period and computers and software are depreciated over two to five years. 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 consolidated statements of operations and comprehensive income 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, 2016 , 2015 or 2014 . 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 $0.3 million and $0.6 million , as of December 31, 2016 and 2015 , 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 were $0.5 million , $0.5 million and $0.3 million for the years ended December 31, 2016 , 2015 and 2014 , 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 each purchase under the employee stock purchase plan (ESPP) is estimated at the beginning of the offering period using the Black-Scholes option pricing model. 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 equity-settled awards is impacted by the price of the Company's common stock as well as changes in assumptions regarding a number of complex and subjective variables. These variables include, but are not limited to, the expected term that awards will remain outstanding, expected common stock price volatility over the term of the awards, risk-free interest rates and expected dividends. The fair value of an award is recognized over the period during which service is required to be performed in exchange for the award, 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 awards 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 prior to the Company's IPO, 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. For all stock options granted to date, t he Company used 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 Comprehensive income consists of net income, unrealized gains or losses on available-for-sale investments and the effects of foreign currency translation adjustments. The Company displays comprehensive income and its components as part of the consolidated statements of operations. Net Income (Loss) Per Share of Common Stock 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 (loss) 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 and common stock warrants are considered common stock equivalents. The Company calculated its basic and diluted net income per share attributable to common stockholders for the years ended December 31, 2015 and 2014 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 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 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 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. Recent Accounting Guidance Recently Adopted Accounting Standards In March 2016, the Financial Accounting Standards Board (FASB) issued a new standard that changes the accounting for certain aspects of share-based payments to employees. The new guidance requires excess tax benefits and tax deficiencies to be recorded in the income statement when stock awards vest or are settled. In addition, cash flows related to excess tax benefits will no longer be separately classified as a financing activity apart from other income tax cash flows. The standard also allows the Company to repurchase more of an employee’s vesting shares for tax withholding purposes without triggering liability accounting, clarifies that all cash payments made to tax authorities on an employee’s behalf for withheld shares should be presented as a financing activity on the consolidated statement of cash flows, and provides an accounting policy election to account for forfeitures as they occur. The new standard is effective for us beginning January 1, 2017, with early adoption permitted. We elected to early adopt the new guidance in the fourth quarter of 2016 which requires us to reflect any adjustments as of January 1, 2016, the beginning of the annual period that includes the interim period of adoption. The impact of adoption was the creation of deferred tax assets in the balance sheet and recognition of excess tax benefits in our provision for (benefit from) income taxes rather than paid-in capital for all periods in fiscal year 2016. Adoption of the new standard resulted in the recognition of excess tax benefits in our benefit from income taxes rather than paid-in capital of $17.2 million for the year ended December 31, 2016. As part of the $17.2 million recognition of excess tax benefits in our benefit from income taxes, the Company elected to carry back the NOL generated in 2016 to the 2014 and 2015 tax years, which resulted in a $3.3 million discrete tax benefit for the year ended December 31, 2016. Additional amendments to the accounting for income taxes and minimum statutory withholding tax requirements had no impact to retained earnings, where the cumulative effect of these changes are required to be recorded. We have elected to continue to estimate forfeitures expected to occur to determine the amount of compensation cost to be recognized in each period. We elected to apply the presentation requirements for cash flows related to excess tax benefits retrospectively to all periods presented which resulted in an increase to net cash from operations and decrease to net cash from financing of $1.6 million for the year ended December 31, 2015 and no impact for the year ended December 31, 2014. The presentation requirements for cash flows related to employee taxes paid for withheld shares had no impact to any of the periods presented on our consolidated cash flows statements since such cash flows have historically been presented as a financing activity. Recently Issued Accounting Standards In May 2014, the 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 March 2016, the FASB issued ASU 2016-08, Revenue from Contracts with Customers — Principal versus Agent Considerations (Reporting Revenue Gross versus Net) , which further clarifies the implementation guidance on principal versus agent considerations contained in ASU 2014-09. In April 2016, the FASB issued ASU 2016-10, Revenue from Contracts with Customers — Identifying Performance Obligations and Licensing , which further clarifies the implementation guidance relating to identifying performance obligations and the licensing implementation guidance. In May 2016, the FASB issued ASU 2016-12, Revenue from Contracts with Customers — Narrow-Scope improvements and Practical Expedients , which further clarifies the implementation on narrow scope improvements and practical expedients. In December 2016, the FASB issued ASU 2016-20, Technical Corrections and Improvements to Topic 606 — Revenue from Contracts with Customer s , which makes minor corrections or minor improvements to the Codification related to ASU No. 2014-09 that are not expected to have a significant effect on current accounting practice. These standards will be effective for the Company in the first quarter of 2018 pursuant to ASU No. 2015-14, Revenue from Contracts with Customers - Deferral of the Effective Date , issued by the FASB in August 20 15. The Company is currently evaluating the financial statement impact of adopting the new standard as well as the transition method for implementation. The Company will be impacted by the new standard regarding the timing of fulfillment of delivery criterion. 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 does not expect the adoption of this ASU to have a significant impact on our financial position. In February 2016, the FASB issued ASU No. 2016-02, Leases , which amends the existing accounting standards for leases. Under the new guidance, a lessee will be required to recognize a lease liability and right-of-use asset for all leases with terms in excess of twelve months. The new guidance also modifies the classification criteria and accounting for sales-type and direct financing leases, and requires additional disclosures to enable users of financial statements to understand the amount, timing, and uncertainty of cash flows arising from leases. Consistent with current guidance, a lessee’s recognition, measurement, and presentation of expenses and cash flows arising from a lease will continue to depend primarily on its classification. The accounting standard is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years, and must be applied using a modified retrospective approach. Early adoption is permitted. While the Company is continuing to assess all potential impacts of the standard, it expects that most of its lease commitments will be subject to the updated standard and recognized as lease liabilities and right-of-use assets upon adoption. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments-Credit Losses . The standard changes how entities will measure credit losses for most financial assets and certain other instruments that are not measured at fair value through net income. The Company will recognize an allowance for credit losses on available-for-sale securities rather than deductions in amortized cost. The standard is effective for fiscal years and interim periods beginning after December 15, 2019. Early adoption is permitted for all periods beginning after December 15, 2018. The Company is currently evaluating the impact of adopting this standard.

Initial Public Offering (IPO)

Initial Public Offering (IPO)	12 Months Ended
	Dec. 31, 2016
Equity [Abstract]
Initial Public Offering (IPO)	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. 8. Preferred Stock and Common Stock Preferred Stock The Company has 5,000,000 of authorized preferred stock issuable. There is no preferred stock outstanding as of December 31, 2016 and 2015 . 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. 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, repurchasing 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, 2016
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. 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, 2016 or 2015 . The Company did not have any financial assets and liabilities measured at fair value on a non-recurring basis as of December 31, 2016 and 2015 . During the years ended December 31, 2016 , 2015 and 2014 , 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, 2016 Level 1 Level 2 Level 3 Fair Value Financial Assets Cash equivalents: Money market funds $ 873 $ — $ — $ 873 Marketable investments: Commercial paper — 4,238 — 4,238 U.S. Treasury 4,996 — — 4,996 U.S. Agency securities — 8,794 — 8,794 U.S. States and Municipalities — 27,355 — 27,355 Corporate bonds — 68,925 — 68,925 Non-U.S. Government debt securities — 1,209 — 1,209 Total $ 5,869 $ 110,521 $ — $ 116,390 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

Balance Sheet Components

Balance Sheet Components	12 Months Ended
	Dec. 31, 2016
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, 2014 $ 471 $ 150 $ (19 ) $ 602 December 31, 2015 602 (13 ) — 589 December 31, 2016 589 216 (121 ) 684 Prepaid Expenses and Other Current Assets The Company’s prepaid expenses and other current assets comprised of the following (in thousands): December 31, 2016 2015 Prepaid taxes $ 4,656 $ 2,736 Prepaid expenses 4,573 4,706 Income tax receivable 4,536 606 Other current assets 4,962 1,304 Prepaid expenses and other current assets $ 18,727 $ 9,352 Marketable Investments The Company’s marketable investments as of December 31, 2016 and 2015 were as follows (in thousands): December 31, 2016 Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Commercial paper $ 4,237 $ 1 $ — $ 4,238 U.S. Treasury 4,996 — — 4,996 U.S. Agency securities 8,803 3 (12 ) 8,794 U.S. States and Municipalities 27,429 1 (75 ) 27,355 Corporate bonds 69,009 36 (120 ) 68,925 Non-U.S. Government debt securities 1,209 — — 1,209 Total $ 115,683 $ 41 $ (207 ) $ 115,517 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 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, 2016 and 2015 (in thousands): December 31, 2016 Fair Value Gross Unrealized Losses U.S. Agency securities 3,291 (12 ) U.S. States and Municipalities 22,286 (75 ) Corporate bonds 29,748 (120 ) Total $ 55,325 $ (207 ) December 31, 2015 Fair Value Gross Unrealized Losses Commercial paper $ 4,746 $ (1 ) U.S. Treasury 12,453 (27 ) U.S. Agency securities 13,475 (34 ) U.S. States and Municipalities 2,084 (2 ) Corporate bonds 59,163 (189 ) Non-U.S. government debt securities 5,881 (16 ) Total $ 97,802 $ (269 ) As of December 31, 2016 and 2015 , 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, 2016 and 2015 were as follows (in thousands): December 31, 2016 2015 Marketable Investments Fair Value Fair Value Due in one year $ 71,051 $ 62,983 Due in one to five years 44,466 66,274 Total $ 115,517 $ 129,257 Inventories The components of inventories consisted of the following (in thousands): December 31, 2016 2015 Raw materials $ 11,367 $ 9,176 Work in process 3,663 2,746 Finished goods 57,982 44,839 Inventories $ 73,012 $ 56,761 Property and Equipment, Net Property and equipment, net consisted of the following (in thousands): December 31, 2016 2015 Machinery and equipment $ 9,734 $ 8,559 Furniture and fixtures 4,246 2,091 Leasehold improvements 10,207 1,564 Software 1,221 666 Computers 884 565 Construction in progress 2,193 577 Total property and equipment 28,485 14,022 Less: Accumulated depreciation and amortization (7,021 ) (5,071 ) Property and equipment, net $ 21,464 $ 8,951 Depreciation and amortization expense was $2.3 million , $1.8 million and $0.8 million for the years ended December 31, 2016 , 2015 and 2014 , respectively. Accrued Liabilities The following table shows the components of accrued liabilities (in thousands): December 31, 2016 2015 Payroll and employee-related cost $ 16,956 $ 13,653 Sales return reserve 2,753 3,247 Preclinical and clinical trial cost 2,054 1,330 Deferred revenue 344 526 Product warranty 1,254 713 Sales and VAT tax payable 733 531 Income tax payable 174 308 Other accrued liabilities 7,422 5,273 Total accrued liabilities $ 31,690 $ 25,581 The estimated product warranty accrual was as follows (in thousands): December 31, 2016 2015 2014 Balance at the beginning of the year $ 713 $ 314 $ 323 Accruals of warranties issued 1,176 752 149 Settlements of warranty claims (635 ) (353 ) (158 ) Balance at the end of the year $ 1,254 $ 713 $ 314

Credit Facility

Credit Facility	12 Months Ended
	Dec. 31, 2016
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 outstanding balance on the credit facility and terminated the credit facility.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Lease Commitments The Company leases its offices under non-cancelable operating leases that expire at various dates from 2029 to 2031 , subject to our option to renew certain leases for an additional five to fifteen years. From time to time through December 31, 2025, 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 of which 15,882 square feet was added to the lease in 2016 . The additional space could potentially result in approximately $1.5 million of annual rent expense based on current terms of the lease. 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. The Company leases its other equipment under non-cancelable operating leases that expire at various dates through 2021 . Rent expense for the years ended December 31, 2016 , 2015 and 2014 was $5.2 million , $3.2 million and $1.8 million , respectively. In addition to the amounts included in the table below, certain lease agreements require the Company to make payments during the lease term for taxes, insurance and other operating expenses. Future minimum lease payments under the non-cancelable operating leases as of December 31, 2016 are as follows (in thousands): Lease Payments Year Ending December 31: 2017 $ 5,554 2018 5,568 2019 5,610 2020 5,642 2021 5,234 Thereafter 50,919 Total future minimum lease payments $ 78,527 Purchase Commitments The Company had non-cancellable purchase obligations to suppliers at December 31, 2016 of $3.5 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, 2016 and 2015 , the license agreement requires minimum annual royalty payments of $0.1 million in equal quarterly installments. 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 November 2013, the Company entered into an agreement that requires the Company to pay, on a quarterly basis, a 3% royalty on the first $5 million in sales and a 1% royalty on sales thereafter of products covered under applicable patents. Unless the agreement is terminated earlier, the royalty for each covered product shall continue until 2030. 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, 2016 , 2015 and 2014 was $2.9 million , $2.0 million and $1.1 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. In many such arrangements, the Company agrees to indemnify, hold harmless, and reimburse the indemnified parties for losses suffered or incurred by the indemnified parties 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 Company also agrees to indemnify many purchasers for product defect and similar claims. 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 any of these indemnification requirements 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 had requested indemnification from the Company but was dismissed from the case in July 2016. The case is in the discovery phase, and 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.

Preferred Stock and Common Stoc

Preferred Stock and Common Stock	12 Months Ended
	Dec. 31, 2016
Temporary Equity Disclosure [Abstract]
Preferred Stock and Common Stock	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. 8. Preferred Stock and Common Stock Preferred Stock The Company has 5,000,000 of authorized preferred stock issuable. There is no preferred stock outstanding as of December 31, 2016 and 2015 . 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. 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, repurchasing 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, 2016
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, 2016 and 2015 , 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 1,002,307 and 1,757,282 shares of common stock were outstanding, and options to purchase 4,263 and 12,339 shares of common stock had been early exercised and were unvested and subject to repurchase, as of December 31, 2016 and 2015 , 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, 2016 and 2015 , 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, 2016 and 2015 , respectively. As of December 31, 2016 and 2015 , the Company had granted 505,000 and 505,000 shares of restricted stock under the 2011 Plan, of which 150,125 and 249,125 shares were unvested and subject to forfeiture and 9,667 and 4,667 shares had been forfeited as of December 31, 2016 and 2015 , 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, 5,733,259 shares of common stock were reserved for issuance and as of December 31, 2016 , 3,683,576 shares of common stock were available for grant. As of December 31, 2016 and 2015 , the Company had granted options to purchase 1,857,900 and 1,857,900 shares of common stock under the 2014 Plan, 1,729,648 and 1,853,063 of which were outstanding and 21,886 and 4,421 of which had been forfeited as of December 31, 2016 and 2015 , respectively. The Company had granted 673,361 and 673,361 shares of restricted stock under the 2014 Plan, as of December 31, 2016 and 2015 , respectively, of which 494,896 and 508,646 shares were unvested and subject to forfeiture as of such dates. The Company had granted 427,896 and 91,800 shares of RSU under the 2014 Plan, as of December 31, 2016 and 2015 , respectively, of which 357,923 and 91,800 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. As of December 31, 2016 , 684,953 shares of common stock were reserved for issuance. 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 ended 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. As of December 31, 2016, 214,025 shares of common stock have been issued under the plan. 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 4,263 and 12,339 as of December 31, 2016 and 2015 , 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, 2016 and 2015 , cash received related to unvested shares totaled $0.03 million and $0.1 million , respectively. Amounts recorded are transferred into common stock and additional paid-in-capital as the shares vest. Stock Options Activity of stock options under the 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, 2015 3,755,345 $ 12.13 Exercised (860,424 ) 3.62 Canceled/Forfeited (17,966 ) 17.68 Balance, December 31, 2016 2,876,955 $ 14.63 Vested and expected to vest—December 31, 2016 2,858,851 $ 14.58 6.71 $ 140,713 Exercisable—December 31, 2016 1,694,078 $ 9.89 5.49 $ 91,330 The total intrinsic value of stock options exercised during the year ended December 31, 2016 , 2015 and 2014 was $53.1 million , $13.1 million and $3.8 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 and $3.69 per share during the years ended 2015 and 2014 , respectively. Restricted Stock and Restricted Stock Units The activity of unvested restricted stock and restricted stock units under the Plans during the year ended December 31, 2016 is set forth below: Number of Shares Weighted Average Grant Date Fair Value Unvested at December 31, 2015 849,571 $ 15.12 Granted 336,096 62.25 Vested (174,723 ) 23.30 Canceled/Forfeited (8,000 ) 21.38 Unvested at December 31, 2016 1,002,944 $ 29.44 The fair value of the restricted stock and restricted stock units that vested during the year ended December 31, 2016 , 2015 and 2014 was $9.9 million , $4.0 million and $0.4 million , respectively. Employee Stock Purchase Plan Under the Penumbra, Inc. ESPP, employees purchased 214,025 shares for $6.6 million during the year ended December 31, 2016 . Stock-based Compensatio n The Company uses the Black-Scholes option pricing model to determine the fair value of stock options and ESPP. 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 equity settled awards: Equity Settled Awards Year Ended December 31, 2016 2015 2014 Expected term (in years) .50 6.08—6.25 6.25 Expected volatility 40% 45% 45% Risk-free interest rate 0.48% 1.56%—1.78% 1.76%—2.02% Expected dividend rate 0% 0% 0% The Company did not grant any options during the year ended December 31, 2016 . 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. 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 was no public market through mid-September 2015 for the Company’s common stock and lack of company-specific historical volatility, the Company 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 considered 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 following table sets forth the stock-based compensation expense included in the consolidated statements of operations (in thousands): Year Ended December 31, 2016 2015 2014 Cost of sales $ 1,132 $ 316 $ 267 Research and development 1,020 444 96 Sales, general and administrative 12,485 6,511 1,070 $ 14,637 $ 7,271 $ 1,433 As of December 31, 2016 , total unrecognized compensation cost was $34.7 million related to unvested share-based compensation arrangements which is expected to be recognized over a weighted average period of 2.8 years. The total stock-based compensation cost capitalized in inventory was $0.4 million and $0.3 million as of December 31, 2016 and 2015 , respectively. The total stock-based compensation cost capitalized in inventory was insignificant as of December 31, 2014 .

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income	12 Months Ended
	Dec. 31, 2016
Equity [Abstract]
Accumulated Other Comprehensive Income	Accumulated Other Comprehensive Loss Other comprehensive loss 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 (loss) items accumulate and are included within accumulated other comprehensive loss. Unrealized gains and losses on our marketable investments are reclassified from accumulated other comprehensive loss 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 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 loss into earnings affect our consolidated statements of operations (in thousands): Year Ended December 31, 2016 Year Ended December 31, 2015 Marketable Currency Translation Total Marketable Currency Translation Total Balance, beginning of the year $ (163 ) $ (1,952 ) $ (2,115 ) $ (220 ) $ (644 ) $ (864 ) Other comprehensive income before reclassifications: Unrealized gains (losses)—marketable investments 98 — 98 (417 ) — (417 ) Foreign currency translation (losses) gains — (2,628 ) (2,628 ) — (1,425 ) (1,425 ) Income tax effect—(expense) benefit (35 ) (3 ) (38 ) 128 117 245 Net of tax 63 (2,631 ) (2,568 ) (289 ) (1,308 ) (1,597 ) Amounts reclassified from accumulated other comprehensive loss to earnings: Realized (gains) losses—marketable investments (8 ) — (8 ) 540 — 540 Income tax effect—benefit (expense) 3 — 3 (194 ) — (194 ) Net of tax (5 ) — (5 ) 346 — 346 Net current-year other comprehensive income (loss) 58 (2,631 ) (2,573 ) 57 (1,308 ) (1,251 ) Balance, end of the year $ (105 ) $ (4,583 ) $ (4,688 ) $ (163 ) $ (1,952 ) $ (2,115 )

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2016
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 $0.8 million and $0.3 million for the years ended December 31, 2016 and 2015 , respectively.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2016
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 United States and foreign jurisdictions. Significant judgments and estimates are required in determining the consolidated income tax expense (benefit). The Company is incorporated in the United States and operates in various countries with different 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, 2016 , 2015 and 2014 is summarized as follows: Year Ended December 31, 2016 2015 2014 United States $ (944 ) $ 2,955 $ 2,230 Foreign 75 1,069 909 Total income (loss) before provision for (benefit from) income taxes $ (869 ) $ 4,024 $ 3,139 Income tax provision or (benefit) in 2016 , 2015 and 2014 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, 2016 2015 2014 Current: Federal $ (3,872 ) $ 3,815 $ 1,155 State 304 603 274 Foreign 772 492 323 Total current (2,796 ) 4,910 1,752 Deferred: Federal (11,909 ) (3,025 ) (625 ) State (785 ) (251 ) (116 ) Foreign (193 ) 25 (117 ) Total deferred (12,887 ) (3,251 ) (858 ) Provision for (benefit from) income taxes $ (15,683 ) $ 1,659 $ 894 The Company’s actual provision for tax or (benefit from 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, 2016 2015 2014 Income tax at federal statutory rate 34.0 % 34.0 % 34.0 % State income taxes, net of federal benefit 75.9 1.9 3.2 Foreign taxes differential (63.0 ) (9.0 ) 5.2 Prepaid tax ASC 810-10 59.0 2.1 (8.9 ) IRC 199 deduction — (7.4 ) (7.0 ) Stock-based compensation 1,474.0 14.8 6.0 Non- deductible meals and entertainment (92.6 ) 5.6 5.8 Imputed interest (30.7 ) 4.7 6.6 Tax credits 395.5 (11.6 ) (12.1 ) Other (47.4 ) 3.6 2.8 Change in valuation allowance 0.3 2.5 (7.1 ) Effective tax rate 1,805.0 % 41.2 % 28.5 % Deferred income tax assets and liabilities consist of the following: December 31, 2016 2015 Deferred tax assets Net operating loss carryforwards $ 5,983 $ 1,000 Tax credits 6,260 1,355 Accruals and reserves 7,668 5,048 Stock-based compensation 3,703 1,352 Translation adjustment 690 715 UNICAP adjustments 4,721 3,840 Other 938 870 Gross deferred tax assets 29,963 14,180 Valuation allowance (6,062 ) (2,702 ) Total deferred tax assets 23,901 11,478 Deferred tax liabilities Depreciation and amortization (1,425 ) (1,335 ) Total deferred tax liabilities (1,425 ) (1,335 ) Net deferred tax assets $ 22,476 $ 10,143 As of December 31, 2014 , the Company released the valuation allowance against the German net deferred tax assets of $0.3 million . As of December 31, 2015 , the Company maintained a full valuation allowance against the net deferred tax assets of California and Canada. As of December 31, 2016 , the Company adopted ASU 2016-09 and the impact of the adoption was creation of additional deferred tax assets of NOL and credits carryforwards. The Company assessed the ability to realize 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 a result, the Company continued to maintain a full valuation allowance against the net deferred tax assets of California and Canada at December 31, 2016 , but determined a valuation allowance was not necessary for remaining deferred tax assets. The valuation allowance against net deferred tax assets changed as follows: December 31, 2016 2015 2014 Balance at the beginning of the year $ 2,702 $ 2,945 $ 3,860 Release of valuation allowance — (243 ) (321 ) Other reserves and deferrals 3,360 — (594 ) Balance at the end of the year $ 6,062 $ 2,702 $ 2,945 At December 31, 2016 , the Company had approximately $10.7 million , $32.7 million and $1.3 million of federal, state and foreign net operating loss carryforwards, respectively, available to offset future taxable income. The federal net operating loss carryforwards are generally carried forward for 20 years. The state net operating loss carryforwards will begin to expire in 2020. At December 31, 2016 , the Company had federal research credits of $3.6 million and California state tax credits of $5.0 million . The federal research credits are generally carried forward for 20 years. California state tax credits may be carried forward indefinitely. 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 $3.8 million balance of unrecognized tax benefits as of December 31, 2016 is $2.1 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, 2014 to December 31, 2016 , is as follows: December 31, 2016 2015 2014 Beginning Balance $ 3,619 $ 1,726 $ 1,325 Gross increase for tax positions of current year 1,213 1,023 401 Gross increase for tax positions of prior years 250 1,062 — Gross decrease for tax positions of prior years (648 ) — — Settlement (387 ) — — Lapse of statute of limitations (220 ) (192 ) — Ending Balance $ 3,827 $ 3,619 $ 1,726 The Company recognizes interest and penalties related to uncertain tax positions in income tax expense. Income tax expense for the years ended December 31, 2016, 2015 and 2014 included interest and penalties that were not material. As of December 31, 2016 and 2015 the Company had approximately $0.1 million and $0.1 million respectively, of accrued interest and penalties attributable 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, 2016 remain subject to examination by federal and state tax authorities. In Australia and Canada, tax years ending December 31, 2009 through December 31, 2016 generally remain subject to examination by tax authorities. In Germany, tax years ending December 31, 2013 through December 31, 2016 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, 2016
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, 2016 2015 2014 Net income (loss) per share: Numerator Net income $ 14,814 $ 2,365 $ 2,245 Less: Deemed dividend paid to convertible preferred stockholders upon repurchase — — (6,344 ) Less: Undistributed income attributable to convertible preferred stockholders — (1,281 ) — Add: Undistributed loss attributable to convertible preferred stockholders — — 3,266 Net income attributable to common stockholders—basic and diluted $ 14,814 $ 1,084 $ (833 ) Denominator Weighted average shares used to compute net income (loss) attributable to common stockholders—Basic 30,464,583 11,993,429 4,609,375 Potential dilutive stock-based awards, as calculated using treasury stock method 3,013,495 2,226,221 — Weighted average shares used to compute net income (loss) attributable to common stockholders—Diluted 33,478,078 14,219,650 4,609,375 Net income (loss) per share attributable to common stockholders —Basic $ 0.49 $ 0.09 $ (0.18 ) —Diluted $ 0.44 $ 0.08 $ (0.18 ) For the years ended December 31, 2016 , 2015 and 2014 , outstanding stock-based awards of 0.3 million , 1.4 million and 3.3 million shares, respectively, were excluded from the computation of diluted net income per share because their effect would have been anti-dilutive.

Geographic Areas and Product Sa

Geographic Areas and Product Sales	12 Months Ended
	Dec. 31, 2016
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, 2016 2015 2014 United States $ 176,104 $ 127,311 $ 82,965 Japan 30,284 19,016 14,699 Other International 56,929 39,768 27,846 Total $ 263,317 $ 186,095 $ 125,510 The following table sets forth revenue by product category (in thousands): Year Ended December 31, 2016 2015 2014 Neuro $ 185,533 $ 141,410 $ 106,242 Peripheral Vascular 77,784 44,685 19,268 Total $ 263,317 $ 186,095 $ 125,510 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, 2016
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 2016 as reported and as adjusted for ASU 2016-09 (in thousands, except share and per share amounts): Quarter Ended As Reported As Adjusted 2016 March 31 June 30 September 30 December 31 March 31 June 30 September 30 Selected Statement of Operations Data: Revenue $ 57,919 $ 65,106 $ 67,187 $ 73,105 $ 57,919 $ 65,106 $ 67,187 Cost of revenue 18,014 23,636 24,313 26,525 18,014 23,636 24,313 Gross profit $ 39,905 $ 41,470 $ 42,874 $ 46,580 $ 39,905 $ 41,470 $ 42,874 (Loss) Income before provision for (benefit from) income taxes $ 2,121 $ (383 ) $ (1,092 ) $ (1,515 ) $ 2,121 $ (383 ) $ (1,092 ) Provision for (benefit from) income taxes $ 1,341 $ (568 ) $ 14 $ 881 $ (170 ) $ (3,396 ) $ (12,998 ) Net income (loss) $ 780 $ 185 $ (1,106 ) $ (2,396 ) $ 2,291 $ 3,013 $ 11,906 Net income (loss) attributable to common stockholders $ 780 $ 185 $ (1,106 ) $ (2,396 ) $ 2,291 $ 3,013 $ 11,906 Net income (loss) per share attributable to common stockholders—Basic $ 0.03 $ 0.01 $ (0.04 ) $ (0.08 ) $ 0.08 $ 0.10 $ 0.39 Net income (loss) per share attributable to common stockholders—Diluted $ 0.02 $ 0.01 $ (0.04 ) $ (0.08 ) $ 0.07 $ 0.09 $ 0.35 Weighted average shares used to compute net income (loss) per share attributable to common stockholders—Basic 29,990,006 30,210,322 30,604,384 31,045,700 29,990,006 30,210,322 30,604,384 Weighted average shares used to compute net income (loss) per share attributable to common stockholders—Diluted 32,486,516 32,693,684 30,604,384 31,045,700 33,023,495 33,308,193 33,755,383 The following table provides the selected quarterly financial data for 2015 (in thousands, except share and per share amounts): Quarter Ended 2015 March 31 June 30 September 30 December 31 Selected Statement of Operations Data: Revenue $ 38,952 $ 42,311 $ 50,416 $ 54,416 Cost of revenue 12,224 14,936 16,919 17,958 Gross profit $ 26,728 $ 27,375 $ 33,497 $ 36,458 Income (loss) before provision for (benefit from) income taxes $ 4,242 $ (4,178 ) $ 2,084 $ 1,876 Net (loss) income $ 2,502 $ (2,671 ) $ 901 $ 1,633 Net (loss) income attributable to common stockholders $ 503 $ (553 ) $ 276 $ 1,633 Net (loss) income per share attributable to common stockholders—Basic $ 0.10 $ (0.11 ) $ 0.04 $ 0.05 Net (loss) income per share attributable to common stockholders—Diluted $ 0.07 $ (0.11 ) $ 0.03 $ 0.05 Weighted average shares used to compute net (loss) income per share attributable to common stockholders—Basic 4,903,535 5,096,151 7,853,730 29,890,944 Weighted average shares used to compute net (loss) income per share attributable to common stockholders—Diluted 7,193,452 5,096,151 10,189,248 32,321,410 The following table provides the selected statement of cash flow data for 2016 and 2015 as reported and as adjusted for ASU 2016-09 (in thousands): As Reported As Adjusted 2016 Three months ended March 31 Six months ended June 30 Nine months ended September 30 Three months ended March 31 Six months ended June 30 Nine months ended September 30 Selected Statement of Cash Flow Data: Net cash (used in) provided by operating activities $ (3,584 ) $ (12,555 ) $ (10,051 ) $ (2,074 ) $ (8,182 ) $ (2,450 ) Net cash provided by (used in) financing activities $ (3 ) $ 7,803 $ 12,253 $ (1,513 ) $ 3,430 $ 4,652 As Reported As Adjusted 2015 Three months ended March 31 Six months ended June 30 Nine months ended September 30 Three months ended March 31 Six months ended June 30 Nine months ended September 30 Selected Statement of Cash Flow Data: Net cash (used in) provided by operating activities $ (2,662 ) $ (8,331 ) $ (12,631 ) $ (2,662 ) $ (8,331 ) $ (11,374 ) Net cash provided by (used in) financing activities $ 326 $ (2,974 ) $ 125,194 $ 326 $ (2,974 ) $ 123,937 The following table provides the selected balance sheet data for 2016 and 2015 as reported and as adjusted for ASU 2016-09 (in thousands): As Reported As Adjusted 2016 March 31 June 30 September 30 March 31 June 30 September 30 Balance Sheet Data: Prepaid expenses and other current assets $ 11,512 $ 17,406 $ 18,665 $ 11,512 $ 17,371 $ 19,209 Total current assets $ 253,651 $ 260,252 $ 267,223 $ 253,651 $ 260,217 $ 267,767 Deferred taxes $ 11,318 $ 11,422 $ 13,394 $ 11,318 $ 11,422 $ 22,059 Total assets $ 275,121 $ 283,979 $ 297,279 $ 275,121 $ 283,944 $ 306,488 Other non-current liabilities $ 3,094 $ 4,199 $ 6,081 $ 3,094 $ 4,199 $ 5,540 Total liabilities $ 37,073 $ 36,388 $ 43,425 $ 37,073 $ 36,388 $ 42,884 Additional paid-in-capital $ 255,499 $ 266,650 $ 275,031 $ 253,988 $ 262,276 $ 267,429 Accumulated deficit $ (16,695 ) $ (16,510 ) $ (17,616 ) $ (15,184 ) $ (12,171 ) $ (264 ) Total stockholders' equity $ 238,048 $ 247,591 $ 253,854 $ 238,048 $ 247,556 $ 263,604 Total liabilities and stockholders' equity $ 275,121 $ 283,979 $ 297,279 $ 275,121 $ 283,944 $ 306,488

Summary of Significant Accoun23

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Basis of Presentation and Consolidation	Basis of Presentation and Consolidation The accompanying consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (U.S. GAAP). Certain changes in presentation were made in the consolidated financial statements for the year ended December 31, 2015 and 2014 , to conform to the presentation for the year ended December 31, 2016 . 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 consolidated operating results for the purpose of allocating resources and evaluating financial performance.
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 loss 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 expense, net in the consolidated statements of operations and comprehensive income. The Company recognized net foreign currency transaction losses of $0.7 million , $0.1 million and $0.3 million during the years ended December 31, 2016 , 2015 and 2014 , 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.
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, 2016 and held cash in foreign banks of approximately $2.1 million and $1.9 million at December 31, 2016 and 2015 , respectively, which was not federally insured. The Company’s revenue has been derived from sales of its products in the United States 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 FDA prior to commencing commercial sales in the United States . 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 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. Machinery and equipment and furniture and fixtures are depreciated over a five to ten year period and computers and software are depreciated over two to five years. 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 consolidated statements of operations and comprehensive income 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
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 $0.3 million and $0.6 million , as of December 31, 2016 and 2015 , 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.
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 each purchase under the employee stock purchase plan (ESPP) is estimated at the beginning of the offering period using the Black-Scholes option pricing model. 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 equity-settled awards is impacted by the price of the Company's common stock as well as changes in assumptions regarding a number of complex and subjective variables. These variables include, but are not limited to, the expected term that awards will remain outstanding, expected common stock price volatility over the term of the awards, risk-free interest rates and expected dividends. The fair value of an award is recognized over the period during which service is required to be performed in exchange for the award, 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 awards 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 prior to the Company's IPO, 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. For all stock options granted to date, t he Company used 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 Comprehensive income consists of net income, unrealized gains or losses on available-for-sale investments and the effects of foreign currency translation adjustments. The Company displays comprehensive income and its components as part of the consolidated statements of operations.
Net Income (Loss) Per Share of Common Stock	Net Income (Loss) Per Share of Common Stock 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 (loss) 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 and common stock warrants are considered common stock equivalents. The Company calculated its basic and diluted net income per share attributable to common stockholders for the years ended December 31, 2015 and 2014 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 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 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 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.
Recently Issued Accounting Standards	Recently Issued Accounting Standards In May 2014, the 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 March 2016, the FASB issued ASU 2016-08, Revenue from Contracts with Customers — Principal versus Agent Considerations (Reporting Revenue Gross versus Net) , which further clarifies the implementation guidance on principal versus agent considerations contained in ASU 2014-09. In April 2016, the FASB issued ASU 2016-10, Revenue from Contracts with Customers — Identifying Performance Obligations and Licensing , which further clarifies the implementation guidance relating to identifying performance obligations and the licensing implementation guidance. In May 2016, the FASB issued ASU 2016-12, Revenue from Contracts with Customers — Narrow-Scope improvements and Practical Expedients , which further clarifies the implementation on narrow scope improvements and practical expedients. In December 2016, the FASB issued ASU 2016-20, Technical Corrections and Improvements to Topic 606 — Revenue from Contracts with Customer s , which makes minor corrections or minor improvements to the Codification related to ASU No. 2014-09 that are not expected to have a significant effect on current accounting practice. These standards will be effective for the Company in the first quarter of 2018 pursuant to ASU No. 2015-14, Revenue from Contracts with Customers - Deferral of the Effective Date , issued by the FASB in August 20 15. The Company is currently evaluating the financial statement impact of adopting the new standard as well as the transition method for implementation. The Company will be impacted by the new standard regarding the timing of fulfillment of delivery criterion. 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 does not expect the adoption of this ASU to have a significant impact on our financial position. In February 2016, the FASB issued ASU No. 2016-02, Leases , which amends the existing accounting standards for leases. Under the new guidance, a lessee will be required to recognize a lease liability and right-of-use asset for all leases with terms in excess of twelve months. The new guidance also modifies the classification criteria and accounting for sales-type and direct financing leases, and requires additional disclosures to enable users of financial statements to understand the amount, timing, and uncertainty of cash flows arising from leases. Consistent with current guidance, a lessee’s recognition, measurement, and presentation of expenses and cash flows arising from a lease will continue to depend primarily on its classification. The accounting standard is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years, and must be applied using a modified retrospective approach. Early adoption is permitted. While the Company is continuing to assess all potential impacts of the standard, it expects that most of its lease commitments will be subject to the updated standard and recognized as lease liabilities and right-of-use assets upon adoption. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments-Credit Losses . The standard changes how entities will measure credit losses for most financial assets and certain other instruments that are not measured at fair value through net income. The Company will recognize an allowance for credit losses on available-for-sale securities rather than deductions in amortized cost. The standard is effective for fiscal years and interim periods beginning after December 15, 2019. Early adoption is permitted for all periods beginning after December 15, 2018. The Company is currently evaluating the impact of adopting this standard.

Fair Value of Financial Instr24

Fair Value of Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2016
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, 2016 Level 1 Level 2 Level 3 Fair Value Financial Assets Cash equivalents: Money market funds $ 873 $ — $ — $ 873 Marketable investments: Commercial paper — 4,238 — 4,238 U.S. Treasury 4,996 — — 4,996 U.S. Agency securities — 8,794 — 8,794 U.S. States and Municipalities — 27,355 — 27,355 Corporate bonds — 68,925 — 68,925 Non-U.S. Government debt securities — 1,209 — 1,209 Total $ 5,869 $ 110,521 $ — $ 116,390 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

Balance Sheet Components (Table

Balance Sheet Components (Tables)	12 Months Ended
	Dec. 31, 2016
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, 2014 $ 471 $ 150 $ (19 ) $ 602 December 31, 2015 602 (13 ) — 589 December 31, 2016 589 216 (121 ) 684
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, 2016 2015 Prepaid taxes $ 4,656 $ 2,736 Prepaid expenses 4,573 4,706 Income tax receivable 4,536 606 Other current assets 4,962 1,304 Prepaid expenses and other current assets $ 18,727 $ 9,352
Schedule of Marketable Investments	The Company’s marketable investments as of December 31, 2016 and 2015 were as follows (in thousands): December 31, 2016 Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Commercial paper $ 4,237 $ 1 $ — $ 4,238 U.S. Treasury 4,996 — — 4,996 U.S. Agency securities 8,803 3 (12 ) 8,794 U.S. States and Municipalities 27,429 1 (75 ) 27,355 Corporate bonds 69,009 36 (120 ) 68,925 Non-U.S. Government debt securities 1,209 — — 1,209 Total $ 115,683 $ 41 $ (207 ) $ 115,517 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
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, 2016 and 2015 (in thousands): December 31, 2016 Fair Value Gross Unrealized Losses U.S. Agency securities 3,291 (12 ) U.S. States and Municipalities 22,286 (75 ) Corporate bonds 29,748 (120 ) Total $ 55,325 $ (207 ) December 31, 2015 Fair Value Gross Unrealized Losses Commercial paper $ 4,746 $ (1 ) U.S. Treasury 12,453 (27 ) U.S. Agency securities 13,475 (34 ) U.S. States and Municipalities 2,084 (2 ) Corporate bonds 59,163 (189 ) Non-U.S. government debt securities 5,881 (16 ) Total $ 97,802 $ (269 )
Schedule of Contractual Maturities of Marketable Investments	The contractual maturities of the Company’s marketable investments as of December 31, 2016 and 2015 were as follows (in thousands): December 31, 2016 2015 Marketable Investments Fair Value Fair Value Due in one year $ 71,051 $ 62,983 Due in one to five years 44,466 66,274 Total $ 115,517 $ 129,257
Schedule of Inventories	The components of inventories consisted of the following (in thousands): December 31, 2016 2015 Raw materials $ 11,367 $ 9,176 Work in process 3,663 2,746 Finished goods 57,982 44,839 Inventories $ 73,012 $ 56,761
Schedule of Property and Equipment, Net	Property and equipment, net consisted of the following (in thousands): December 31, 2016 2015 Machinery and equipment $ 9,734 $ 8,559 Furniture and fixtures 4,246 2,091 Leasehold improvements 10,207 1,564 Software 1,221 666 Computers 884 565 Construction in progress 2,193 577 Total property and equipment 28,485 14,022 Less: Accumulated depreciation and amortization (7,021 ) (5,071 ) Property and equipment, net $ 21,464 $ 8,951
Schedule of Accrued Liabilities	The following table shows the components of accrued liabilities (in thousands): December 31, 2016 2015 Payroll and employee-related cost $ 16,956 $ 13,653 Sales return reserve 2,753 3,247 Preclinical and clinical trial cost 2,054 1,330 Deferred revenue 344 526 Product warranty 1,254 713 Sales and VAT tax payable 733 531 Income tax payable 174 308 Other accrued liabilities 7,422 5,273 Total accrued liabilities $ 31,690 $ 25,581
Schedule of Estimated Product Warranty Accrual	The estimated product warranty accrual was as follows (in thousands): December 31, 2016 2015 2014 Balance at the beginning of the year $ 713 $ 314 $ 323 Accruals of warranties issued 1,176 752 149 Settlements of warranty claims (635 ) (353 ) (158 ) Balance at the end of the year $ 1,254 $ 713 $ 314

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2016
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, 2016 are as follows (in thousands): Lease Payments Year Ending December 31: 2017 $ 5,554 2018 5,568 2019 5,610 2020 5,642 2021 5,234 Thereafter 50,919 Total future minimum lease payments $ 78,527

Stock Option Plans (Tables)

Stock Option Plans (Tables)	12 Months Ended
	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Stock Option Activity	Activity of stock options under the 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, 2015 3,755,345 $ 12.13 Exercised (860,424 ) 3.62 Canceled/Forfeited (17,966 ) 17.68 Balance, December 31, 2016 2,876,955 $ 14.63 Vested and expected to vest—December 31, 2016 2,858,851 $ 14.58 6.71 $ 140,713 Exercisable—December 31, 2016 1,694,078 $ 9.89 5.49 $ 91,330
Summary of Unvested Restricted Stock Activity	Restricted Stock and Restricted Stock Units The activity of unvested restricted stock and restricted stock units under the Plans during the year ended December 31, 2016 is set forth below: Number of Shares Weighted Average Grant Date Fair Value Unvested at December 31, 2015 849,571 $ 15.12 Granted 336,096 62.25 Vested (174,723 ) 23.30 Canceled/Forfeited (8,000 ) 21.38 Unvested at December 31, 2016 1,002,944 $ 29.44
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 equity settled awards: Equity Settled Awards Year Ended December 31, 2016 2015 2014 Expected term (in years) .50 6.08—6.25 6.25 Expected volatility 40% 45% 45% Risk-free interest rate 0.48% 1.56%—1.78% 1.76%—2.02% Expected dividend rate 0% 0% 0%
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, 2016 2015 2014 Cost of sales $ 1,132 $ 316 $ 267 Research and development 1,020 444 96 Sales, general and administrative 12,485 6,511 1,070 $ 14,637 $ 7,271 $ 1,433

Accumulated Other Comprehensi28

Accumulated Other Comprehensive Income (Tables)	12 Months Ended
	Dec. 31, 2016
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 loss into earnings affect our consolidated statements of operations (in thousands): Year Ended December 31, 2016 Year Ended December 31, 2015 Marketable Currency Translation Total Marketable Currency Translation Total Balance, beginning of the year $ (163 ) $ (1,952 ) $ (2,115 ) $ (220 ) $ (644 ) $ (864 ) Other comprehensive income before reclassifications: Unrealized gains (losses)—marketable investments 98 — 98 (417 ) — (417 ) Foreign currency translation (losses) gains — (2,628 ) (2,628 ) — (1,425 ) (1,425 ) Income tax effect—(expense) benefit (35 ) (3 ) (38 ) 128 117 245 Net of tax 63 (2,631 ) (2,568 ) (289 ) (1,308 ) (1,597 ) Amounts reclassified from accumulated other comprehensive loss to earnings: Realized (gains) losses—marketable investments (8 ) — (8 ) 540 — 540 Income tax effect—benefit (expense) 3 — 3 (194 ) — (194 ) Net of tax (5 ) — (5 ) 346 — 346 Net current-year other comprehensive income (loss) 58 (2,631 ) (2,573 ) 57 (1,308 ) (1,251 ) Balance, end of the year $ (105 ) $ (4,583 ) $ (4,688 ) $ (163 ) $ (1,952 ) $ (2,115 )

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Schedule of Income or (Loss) before Income Taxes	Income or (loss) before income taxes for the years ended December 31, 2016 , 2015 and 2014 is summarized as follows: Year Ended December 31, 2016 2015 2014 United States $ (944 ) $ 2,955 $ 2,230 Foreign 75 1,069 909 Total income (loss) before provision for (benefit from) income taxes $ (869 ) $ 4,024 $ 3,139
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, 2016 2015 2014 Current: Federal $ (3,872 ) $ 3,815 $ 1,155 State 304 603 274 Foreign 772 492 323 Total current (2,796 ) 4,910 1,752 Deferred: Federal (11,909 ) (3,025 ) (625 ) State (785 ) (251 ) (116 ) Foreign (193 ) 25 (117 ) Total deferred (12,887 ) (3,251 ) (858 ) Provision for (benefit from) income taxes $ (15,683 ) $ 1,659 $ 894
Schedule of Effective Income Tax Reconciliation	The Company’s actual provision for tax or (benefit from 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, 2016 2015 2014 Income tax at federal statutory rate 34.0 % 34.0 % 34.0 % State income taxes, net of federal benefit 75.9 1.9 3.2 Foreign taxes differential (63.0 ) (9.0 ) 5.2 Prepaid tax ASC 810-10 59.0 2.1 (8.9 ) IRC 199 deduction — (7.4 ) (7.0 ) Stock-based compensation 1,474.0 14.8 6.0 Non- deductible meals and entertainment (92.6 ) 5.6 5.8 Imputed interest (30.7 ) 4.7 6.6 Tax credits 395.5 (11.6 ) (12.1 ) Other (47.4 ) 3.6 2.8 Change in valuation allowance 0.3 2.5 (7.1 ) Effective tax rate 1,805.0 % 41.2 % 28.5 %
Schedule of Deferred Tax Assets and Liabilities	Deferred income tax assets and liabilities consist of the following: December 31, 2016 2015 Deferred tax assets Net operating loss carryforwards $ 5,983 $ 1,000 Tax credits 6,260 1,355 Accruals and reserves 7,668 5,048 Stock-based compensation 3,703 1,352 Translation adjustment 690 715 UNICAP adjustments 4,721 3,840 Other 938 870 Gross deferred tax assets 29,963 14,180 Valuation allowance (6,062 ) (2,702 ) Total deferred tax assets 23,901 11,478 Deferred tax liabilities Depreciation and amortization (1,425 ) (1,335 ) Total deferred tax liabilities (1,425 ) (1,335 ) Net deferred tax assets $ 22,476 $ 10,143
Summary of Valuation Allowance	The valuation allowance against net deferred tax assets changed as follows: December 31, 2016 2015 2014 Balance at the beginning of the year $ 2,702 $ 2,945 $ 3,860 Release of valuation allowance — (243 ) (321 ) Other reserves and deferrals 3,360 — (594 ) Balance at the end of the year $ 6,062 $ 2,702 $ 2,945
Schedule of Unrecognized Tax Benefits	A reconciliation of the change in the gross unrecognized tax benefits from January 1, 2014 to December 31, 2016 , is as follows: December 31, 2016 2015 2014 Beginning Balance $ 3,619 $ 1,726 $ 1,325 Gross increase for tax positions of current year 1,213 1,023 401 Gross increase for tax positions of prior years 250 1,062 — Gross decrease for tax positions of prior years (648 ) — — Settlement (387 ) — — Lapse of statute of limitations (220 ) (192 ) — Ending Balance $ 3,827 $ 3,619 $ 1,726

Net Income (Loss) per Share o30

Net Income (Loss) per Share of Common Stock attributable to Common Stockholders (Tables)	12 Months Ended
	Dec. 31, 2016
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, 2016 2015 2014 Net income (loss) per share: Numerator Net income $ 14,814 $ 2,365 $ 2,245 Less: Deemed dividend paid to convertible preferred stockholders upon repurchase — — (6,344 ) Less: Undistributed income attributable to convertible preferred stockholders — (1,281 ) — Add: Undistributed loss attributable to convertible preferred stockholders — — 3,266 Net income attributable to common stockholders—basic and diluted $ 14,814 $ 1,084 $ (833 ) Denominator Weighted average shares used to compute net income (loss) attributable to common stockholders—Basic 30,464,583 11,993,429 4,609,375 Potential dilutive stock-based awards, as calculated using treasury stock method 3,013,495 2,226,221 — Weighted average shares used to compute net income (loss) attributable to common stockholders—Diluted 33,478,078 14,219,650 4,609,375 Net income (loss) per share attributable to common stockholders —Basic $ 0.49 $ 0.09 $ (0.18 ) —Diluted $ 0.44 $ 0.08 $ (0.18 )
Schedule of Antidilutive Securities Excluded from Computation of Earnings per Share	For the years ended December 31, 2016 , 2015 and 2014 , outstanding stock-based awards of 0.3 million , 1.4 million and 3.3 million shares, respectively, were excluded from the computation of diluted net income per share because their effect would have been anti-dilutive.

Geographic Areas and Product 31

Geographic Areas and Product Sales Geographic Areas and Product Sales (Tables)	12 Months Ended
	Dec. 31, 2016
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, 2016 2015 2014 United States $ 176,104 $ 127,311 $ 82,965 Japan 30,284 19,016 14,699 Other International 56,929 39,768 27,846 Total $ 263,317 $ 186,095 $ 125,510
Revenue by Product Category	The following table sets forth revenue by product category (in thousands): Year Ended December 31, 2016 2015 2014 Neuro $ 185,533 $ 141,410 $ 106,242 Peripheral Vascular 77,784 44,685 19,268 Total $ 263,317 $ 186,095 $ 125,510

Selected Quarterly Financial 32

Selected Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information	The following table provides the selected quarterly financial data for 2016 as reported and as adjusted for ASU 2016-09 (in thousands, except share and per share amounts): Quarter Ended As Reported As Adjusted 2016 March 31 June 30 September 30 December 31 March 31 June 30 September 30 Selected Statement of Operations Data: Revenue $ 57,919 $ 65,106 $ 67,187 $ 73,105 $ 57,919 $ 65,106 $ 67,187 Cost of revenue 18,014 23,636 24,313 26,525 18,014 23,636 24,313 Gross profit $ 39,905 $ 41,470 $ 42,874 $ 46,580 $ 39,905 $ 41,470 $ 42,874 (Loss) Income before provision for (benefit from) income taxes $ 2,121 $ (383 ) $ (1,092 ) $ (1,515 ) $ 2,121 $ (383 ) $ (1,092 ) Provision for (benefit from) income taxes $ 1,341 $ (568 ) $ 14 $ 881 $ (170 ) $ (3,396 ) $ (12,998 ) Net income (loss) $ 780 $ 185 $ (1,106 ) $ (2,396 ) $ 2,291 $ 3,013 $ 11,906 Net income (loss) attributable to common stockholders $ 780 $ 185 $ (1,106 ) $ (2,396 ) $ 2,291 $ 3,013 $ 11,906 Net income (loss) per share attributable to common stockholders—Basic $ 0.03 $ 0.01 $ (0.04 ) $ (0.08 ) $ 0.08 $ 0.10 $ 0.39 Net income (loss) per share attributable to common stockholders—Diluted $ 0.02 $ 0.01 $ (0.04 ) $ (0.08 ) $ 0.07 $ 0.09 $ 0.35 Weighted average shares used to compute net income (loss) per share attributable to common stockholders—Basic 29,990,006 30,210,322 30,604,384 31,045,700 29,990,006 30,210,322 30,604,384 Weighted average shares used to compute net income (loss) per share attributable to common stockholders—Diluted 32,486,516 32,693,684 30,604,384 31,045,700 33,023,495 33,308,193 33,755,383 The following table provides the selected quarterly financial data for 2015 (in thousands, except share and per share amounts): Quarter Ended 2015 March 31 June 30 September 30 December 31 Selected Statement of Operations Data: Revenue $ 38,952 $ 42,311 $ 50,416 $ 54,416 Cost of revenue 12,224 14,936 16,919 17,958 Gross profit $ 26,728 $ 27,375 $ 33,497 $ 36,458 Income (loss) before provision for (benefit from) income taxes $ 4,242 $ (4,178 ) $ 2,084 $ 1,876 Net (loss) income $ 2,502 $ (2,671 ) $ 901 $ 1,633 Net (loss) income attributable to common stockholders $ 503 $ (553 ) $ 276 $ 1,633 Net (loss) income per share attributable to common stockholders—Basic $ 0.10 $ (0.11 ) $ 0.04 $ 0.05 Net (loss) income per share attributable to common stockholders—Diluted $ 0.07 $ (0.11 ) $ 0.03 $ 0.05 Weighted average shares used to compute net (loss) income per share attributable to common stockholders—Basic 4,903,535 5,096,151 7,853,730 29,890,944 Weighted average shares used to compute net (loss) income per share attributable to common stockholders—Diluted 7,193,452 5,096,151 10,189,248 32,321,410 The following table provides the selected statement of cash flow data for 2016 and 2015 as reported and as adjusted for ASU 2016-09 (in thousands): As Reported As Adjusted 2016 Three months ended March 31 Six months ended June 30 Nine months ended September 30 Three months ended March 31 Six months ended June 30 Nine months ended September 30 Selected Statement of Cash Flow Data: Net cash (used in) provided by operating activities $ (3,584 ) $ (12,555 ) $ (10,051 ) $ (2,074 ) $ (8,182 ) $ (2,450 ) Net cash provided by (used in) financing activities $ (3 ) $ 7,803 $ 12,253 $ (1,513 ) $ 3,430 $ 4,652 As Reported As Adjusted 2015 Three months ended March 31 Six months ended June 30 Nine months ended September 30 Three months ended March 31 Six months ended June 30 Nine months ended September 30 Selected Statement of Cash Flow Data: Net cash (used in) provided by operating activities $ (2,662 ) $ (8,331 ) $ (12,631 ) $ (2,662 ) $ (8,331 ) $ (11,374 ) Net cash provided by (used in) financing activities $ 326 $ (2,974 ) $ 125,194 $ 326 $ (2,974 ) $ 123,937 The following table provides the selected balance sheet data for 2016 and 2015 as reported and as adjusted for ASU 2016-09 (in thousands): As Reported As Adjusted 2016 March 31 June 30 September 30 March 31 June 30 September 30 Balance Sheet Data: Prepaid expenses and other current assets $ 11,512 $ 17,406 $ 18,665 $ 11,512 $ 17,371 $ 19,209 Total current assets $ 253,651 $ 260,252 $ 267,223 $ 253,651 $ 260,217 $ 267,767 Deferred taxes $ 11,318 $ 11,422 $ 13,394 $ 11,318 $ 11,422 $ 22,059 Total assets $ 275,121 $ 283,979 $ 297,279 $ 275,121 $ 283,944 $ 306,488 Other non-current liabilities $ 3,094 $ 4,199 $ 6,081 $ 3,094 $ 4,199 $ 5,540 Total liabilities $ 37,073 $ 36,388 $ 43,425 $ 37,073 $ 36,388 $ 42,884 Additional paid-in-capital $ 255,499 $ 266,650 $ 275,031 $ 253,988 $ 262,276 $ 267,429 Accumulated deficit $ (16,695 ) $ (16,510 ) $ (17,616 ) $ (15,184 ) $ (12,171 ) $ (264 ) Total stockholders' equity $ 238,048 $ 247,591 $ 253,854 $ 238,048 $ 247,556 $ 263,604 Total liabilities and stockholders' equity $ 275,121 $ 283,979 $ 297,279 $ 275,121 $ 283,944 $ 306,488

Organization and Description 33

Organization and Description of Business (Details)	12 Months Ended
	Dec. 31, 2016market
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of major markets	2

Summary of Significant Accoun34

Summary of Significant Accounting Policies - Additional Disclosures (Details)	Sep. 23, 2015	Dec. 31, 2016USD ($)segmentactivity	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Accounting Policies [Abstract]
Number of business activities | activity		1
Number of operating segments | segment		1
Foreign currency transaction gains (losses)		$ (700,000)	$ (100,000)	$ (300,000)
Other-than-temporary impairments for marketable investments		0	0	0
Inventory write downs		2,667,000	1,163,000	1,852,000
Impairment of long-lived assets		0	0	0
Preferred stock conversion to common stock, conversion ratio	1
Deferred revenue		$ 300,000	600,000
Actual historical return period used for estimating sales return reserves		3 years
Advertising expense		$ 500,000	$ 500,000	$ 300,000

Summary of Significant Accoun35

Summary of Significant Accounting Policies - Concentration of Credit Risk (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)customerfinancial_instituion	Dec. 31, 2015USD ($)	Dec. 31, 2014customer
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
Concentration risk, percentage	11.50%	10.00%	12.00%
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 | $	$ 2.1	$ 1.9

Summary of Significant Accoun36

Summary of Significant Accounting Policies - Property and Equipment, Net (Details)	12 Months Ended
	Dec. 31, 2016
Minimum | Machinery and Equipment and Furniture and Fixtures
Property, Plant and Equipment [Line Items]
Useful life of property and equipment	5 years
Minimum | Computers and Software
Property, Plant and Equipment [Line Items]
Useful life of property and equipment	2 years
Maximum | Machinery and Equipment and Furniture and Fixtures
Property, Plant and Equipment [Line Items]
Useful life of property and equipment	10 years
Maximum | Computers and Software
Property, Plant and Equipment [Line Items]
Useful life of property and equipment	5 years

Summary of Significant Accoun37

Summary of Significant Accounting Policies - New Accounting Pronouncements (Details) - USD ($)	3 Months Ended		6 Months Ended		9 Months Ended		12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Jun. 30, 2016	Jun. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
New Accounting Pronouncement, Early Adoption [Line Items]
Recognition of excess tax benefits							$ 17,200,000
Discrete tax benefits from utilization of carryback NOL							3,300,000
Net cash (used in) provided by operating activities	$ (2,074,000)	$ (2,662,000)	$ (8,182,000)	$ (8,331,000)	$ (2,450,000)	$ (11,374,000)	(12,807,000)	$ (20,689,000)	$ (6,389,000)
Net cash used in financing	$ 1,513,000	$ (326,000)	$ (3,430,000)	$ 2,974,000	$ (4,652,000)	$ (123,937,000)	$ (7,126,000)	(122,834,000)	(42,897,000)
Accounting Standards Update | New Accounting Pronouncement, Early Adoption, Effect
New Accounting Pronouncement, Early Adoption [Line Items]
Net cash (used in) provided by operating activities								1,600,000	0
Net cash used in financing								$ 1,600,000	$ 0

Initial Public Offering (IPO) (

Initial Public Offering (IPO) (Details) $ / shares in Units, $ in Thousands	Sep. 23, 2015USD ($)$ / sharesshares	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Class of Stock [Line Items]
Proceeds from issuance of common stock issued in initial public offering, net of issuance costs		$ 0	$ 124,742	$ 0
Preferred stock conversion to common stock, number of shares (in shares) | shares	19,510,410
Preferred stock conversion to common stock, conversion ratio	1
Initial Public Offering
Class of Stock [Line Items]
Shares issued (in 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 Instr39

Fair Value of Financial Instruments (Details) - Recurring - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Financial Assets
Total	$ 116,390	$ 139,359
Commercial paper
Financial Assets
Marketable investments	4,238	22,332
U.S. Treasury
Financial Assets
Marketable investments	4,996	15,436
U.S. Agency securities
Financial Assets
Marketable investments	8,794	21,464
U.S. States and Municipalities
Financial Assets
Marketable investments	27,355	2,084
Corporate bonds
Financial Assets
Marketable investments	68,925	61,002
Non-U.S. Government debt securities
Financial Assets
Marketable investments	1,209	6,939
Commercial paper
Financial Assets
Cash Equivalents		9,850
Money market funds
Financial Assets
Cash Equivalents	873	252
Level 1
Financial Assets
Total	5,869	15,688
Level 1 | Commercial paper
Financial Assets
Marketable investments	0	0
Level 1 | U.S. Treasury
Financial Assets
Marketable investments	4,996	15,436
Level 1 | U.S. Agency securities
Financial Assets
Marketable investments	0	0
Level 1 | U.S. States and Municipalities
Financial Assets
Marketable investments	0	0
Level 1 | Corporate bonds
Financial Assets
Marketable investments	0	0
Level 1 | Non-U.S. Government debt securities
Financial Assets
Marketable investments	0	0
Level 1 | Commercial paper
Financial Assets
Cash Equivalents		0
Level 1 | Money market funds
Financial Assets
Cash Equivalents	873	252
Level 2
Financial Assets
Total	110,521	123,671
Level 2 | Commercial paper
Financial Assets
Marketable investments	4,238	22,332
Level 2 | U.S. Treasury
Financial Assets
Marketable investments	0	0
Level 2 | U.S. Agency securities
Financial Assets
Marketable investments	8,794	21,464
Level 2 | U.S. States and Municipalities
Financial Assets
Marketable investments	27,355	2,084
Level 2 | Corporate bonds
Financial Assets
Marketable investments	68,925	61,002
Level 2 | Non-U.S. Government debt securities
Financial Assets
Marketable investments	1,209	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	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	0
Level 3 | Corporate bonds
Financial Assets
Marketable investments	0	0
Level 3 | Non-U.S. Government debt securities
Financial Assets
Marketable investments	0	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, 2016	Dec. 31, 2015	Dec. 31, 2014
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance At Beginning Of Year	$ 589	$ 602	$ 471
Charged To Costs And Expenses	216	(13)	150
Deductions	(121)	0	(19)
Balance At End Of Year	$ 684	$ 589	$ 602

Balance Sheet Components - Prep

Balance Sheet Components - Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Prepaid taxes	$ 4,656				$ 2,736
Prepaid expenses	4,573				4,706
Income tax receivable	4,536				606
Other current assets	4,962				1,304
Prepaid expenses and other current assets	$ 18,727	$ 19,209	$ 17,371	$ 11,512	$ 9,352

Balance Sheet Components - Gain

Balance Sheet Components - Gains and Losses of Marketable Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Cost	$ 115,683	$ 129,512
Gross Unrealized Gains	41	14
Gross Unrealized Losses	(207)	(269)
Fair Value	115,517	129,257
Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Cost	4,237	22,328
Gross Unrealized Gains	1	5
Gross Unrealized Losses	0	(1)
Fair Value	4,238	22,332
U.S. Treasury
Schedule of Available-for-sale Securities [Line Items]
Cost	4,996	15,459
Gross Unrealized Gains	0	4
Gross Unrealized Losses	0	(27)
Fair Value	4,996	15,436
U.S. Agency securities
Schedule of Available-for-sale Securities [Line Items]
Cost	8,803	21,497
Gross Unrealized Gains	3	1
Gross Unrealized Losses	(12)	(34)
Fair Value	8,794	21,464
U.S. States and Municipalities
Schedule of Available-for-sale Securities [Line Items]
Cost	27,429	2,086
Gross Unrealized Gains	1	0
Gross Unrealized Losses	(75)	(2)
Fair Value	27,355	2,084
Corporate bonds
Schedule of Available-for-sale Securities [Line Items]
Cost	69,009	61,188
Gross Unrealized Gains	36	3
Gross Unrealized Losses	(120)	(189)
Fair Value	68,925	61,002
Non-U.S. Government debt securities
Schedule of Available-for-sale Securities [Line Items]
Cost	1,209	6,954
Gross Unrealized Gains	0	1
Gross Unrealized Losses	0	(16)
Fair Value	$ 1,209	$ 6,939

Balance Sheet Components - Mark

Balance Sheet Components - Marketable Securities in an Unrealized Loss Position (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Fair Value	$ 55,325,000	$ 97,802,000
Gross Unrealized Losses, less than 12 months	(207,000)	(269,000)
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)
U.S. Treasury
Schedule of Available-for-sale Securities [Line Items]
Fair Value		12,453,000
Gross Unrealized Losses, less than 12 months		(27,000)
U.S. Agency securities
Schedule of Available-for-sale Securities [Line Items]
Fair Value	3,291,000	13,475,000
Gross Unrealized Losses, less than 12 months	(12,000)	(34,000)
U.S. States and Municipalities
Schedule of Available-for-sale Securities [Line Items]
Fair Value	22,286,000	2,084,000
Gross Unrealized Losses, less than 12 months	(75,000)	(2,000)
Corporate bonds
Schedule of Available-for-sale Securities [Line Items]
Fair Value	29,748,000	59,163,000
Gross Unrealized Losses, less than 12 months	$ (120,000)	(189,000)
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, 2016	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Due in one year	$ 71,051	$ 62,983
Due in one to five years	44,466	66,274
Total	$ 115,517	$ 129,257

Balance Sheet Components - Inve

Balance Sheet Components - Inventories (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Raw materials	$ 11,367	$ 9,176
Work in process	3,663	2,746
Finished goods	57,982	44,839
Inventories	$ 73,012	$ 56,761

Balance Sheet Components - Prop

Balance Sheet Components - Property and Equipment, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 28,485	$ 14,022
Less: Accumulated depreciation and amortization	(7,021)	(5,071)
Property and equipment, net	21,464	8,951
Depreciation and amortization expense	2,297	1,752	$ 751
Machinery and equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	9,734	8,559
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Total property and equipment	4,246	2,091
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total property and equipment	10,207	1,564
Software
Property, Plant and Equipment [Line Items]
Total property and equipment	1,221	666
Computers
Property, Plant and Equipment [Line Items]
Total property and equipment	884	565
Construction in progress
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 2,193	$ 577

Balance Sheet Components - Accr

Balance Sheet Components - Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Payroll and employee-related cost	$ 16,956	$ 13,653
Sales return reserve	2,753	3,247
Preclinical and clinical trial cost	2,054	1,330
Deferred revenue	344	526
Product warranty	1,254	713
Sales and VAT tax payable	733	531
Income tax payable	174	308
Other accrued liabilities	7,422	5,273
Total accrued liabilities	$ 31,690	$ 25,581

Balance Sheet Components - Prod

Balance Sheet Components - Product Warranty (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Product Warranty, Increase (Decrease) [Roll Forward]
Balance at the beginning of the year	$ 713	$ 314	$ 323
Accruals of warranties issued	1,176	752	149
Settlements of warranty claims	(635)	(353)	(158)
Balance at the end of the year	$ 1,254	$ 713	$ 314

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%

Commitments and Contingencies -

Commitments and Contingencies - Lease and Purchase Commitments (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)ft²	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Operating Leases [Line Items]
Rent expense	$ 5,200	$ 3,200	$ 1,800
Future minimum lease payments under non-cancelable operating leases
2,017	5,554
2,018	5,568
2,019	5,610
2,020	5,642
2,021	5,234
Thereafter	50,919
Total future minimum lease payments	78,527
Purchase obligations	$ 3,500
Headquarters, Additional Lease
Operating Leases [Line Items]
Rentable area, added to lease in current year (in sqft) | ft²	15,882
Headquarters, Additional Lease | Minimum
Operating Leases [Line Items]
Renewal term	5 years
Headquarters, Additional Lease | Maximum
Operating Leases [Line Items]
Renewal term	15 years
Rentable area (in sqft) | ft²	117,325
Potential | Headquarters, Additional Lease
Operating Leases [Line Items]
Rent expense	$ 1,500

Commitments and Contingencies51

Commitments and Contingencies - Royalty Obligations (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cost of Sales
Other Commitments [Line Items]
Royalty expense	$ 2,900,000	$ 2,000,000	$ 1,100,000
Royalty Agreement, March 2005
Other Commitments [Line Items]
Minimum annual royalty payments	$ 100,000
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, November 2013, Less than $5 Million in Sales [Member]
Other Commitments [Line Items]
Royalty as a percent of sales	3.00%
Royalty Agreement, November 2013, Greater than $5 Million in Sales [Member]
Other Commitments [Line Items]
Royalty as a percent of sales	1.00%
Royalty agreement, threshold	$ 5,000,000
Royalty Agreement, April 2015
Other Commitments [Line Items]
Term of royalty agreement	20 years
Royalty as a percent of sales	2.00%

Commitments and Contingencies52

Commitments and Contingencies - Litigation (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)
Damages from Product
Loss Contingencies [Line Items]
Damages sought, value	$ 35

Preferred Stock and Common St53

Preferred Stock and Common Stock (Details)	1 Months Ended		2 Months Ended	12 Months Ended
	Jul. 31, 2014USD ($)$ / sharesshares	May 31, 2014USD ($)$ / sharesshares	Jun. 30, 2014USD ($)	Dec. 31, 2016voteshares	Dec. 31, 2015USD ($)shares	Dec. 31, 2014USD ($)shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred stock, shares authorized (in shares)				5,000,000	5,000,000
Preferred stock, shares outstanding (in shares)				0	0
Common stock, number of votes per share | vote				1
Share repurchase program, price per share (in dollars per share) | $ / shares		$ 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
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized to be repurchased (in shares)		45,000
Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized to be repurchased (in shares)		70,612
Shares repurchased and retired (in shares)					23,650	115,612
Common Stock | Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Excess between the purchase and issuance price | $			$ 500,000
Preferred Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized to be repurchased (in shares)		45,611
Share repurchase program, price per share (in dollars per share) | $ / shares	$ 13.20
Excess between the purchase and issuance price | $	$ 5,800,000		$ 500,000
Shares repurchased and retired (in shares)	584,052
Value of shares repurchased and retired | $	$ 7,700,000

Stock Option Plans - Stock Plan

Stock Option Plans - Stock Plans (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Sep. 17, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options outstanding ( in shares)	2,876,955	3,755,345
Number of options unvested and subject to repurchase (in shares)	4,263	12,339
Shares purchased by employees under the employee stock purchase plan (in shares)	214,025
Liability relating to cash received from employees for exercise of unvested options	$ 30,000	$ 100,000
Intrinsic value of options exercised in period	53,100,000	$ 13,100,000	$ 3,800,000
Weighted average grant date fair value (in dollars per share)		$ 9.69	$ 3.69
Unrecognized compensation cost related to unvested share-based compensation arrangements	$ 34,700,000
Unrecognized compensation cost, expected recognition period	2 years 9 months 18 days
Share-based compensation expense capitalized in inventory	$ 400,000	$ 300,000
Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares purchased by employees under the employee stock purchase plan (in shares)	214,025
Restricted stock and restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of awards outstanding (in shares)	1,002,944	849,571
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock reserved for future issuance (in shares)	684,953			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 (in shares)	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 (in shares)	5,431,017	5,431,017
Number of options outstanding ( in shares)	1,002,307	1,757,282
Number of options unvested and subject to repurchase (in shares)	4,263	12,339
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 (in shares)	145,000	145,000
Number of options outstanding ( in 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 (in shares)	505,000	505,000
Number of awards outstanding (in shares)	150,125	249,125
Awards forfeited since inception of plan (in shares)	9,667	4,667
2014 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted since inception of plan (in shares)	1,857,900	1,857,900
Number of options outstanding ( in shares)	1,729,648	1,853,063
Shares of common stock reserved for future issuance (in shares)	5,733,259
Number of shares available for grant (in shares)	3,683,576
Options forfeited since inception of plan (in shares)	21,886	4,421
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 (in shares)	673,361	673,361
Number of awards outstanding (in shares)	494,896	508,646
2014 Equity Incentive Plan | RSU
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted since inception of plan (in shares)	427,896	91,800
Number of awards outstanding (in shares)	357,923	91,800

Stock Option Plans - Stock Opti

Stock Option Plans - Stock Option Activity (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)$ / sharesshares
Number of Shares
Beginning balance (in shares) | shares	3,755,345
Exercised (in shares) | shares	(860,424)
Cancelled/Forfeited (in shares) | shares	(17,966)
Ending balance (in shares) | shares	2,876,955
Weighted Average Exercise Price
Beginning balance (in dollars per share) | $ / shares	$ 12.13
Exercised (in dollars per share) | $ / shares	3.62
Cancelled/Forfeited (in dollars per share) | $ / shares	17.68
Ending balance (in dollars per share) | $ / shares	$ 14.63
Options Vested and Expected to Vest
Number of Shares | shares	2,858,851
Weighted Average Exercise Price | $ / shares	$ 14.58
Weighted Average Remaining Contractual Life (in Years)	6 years 8 months 16 days
Aggregate Intrinsic Value (in thousands) | $	$ 140,713
Options Exercisable
Number of Shares | shares	1,694,078
Weighted Average Exercise Price | $ / shares	$ 9.89
Weighted Average Remaining Contractual Life (in Years)	5 years 5 months 27 days
Aggregate Intrinsic Value (in thousands) | $	$ 91,330

Stock Option Plans - Restricted

Stock Option Plans - Restricted Stock Activity (Details) - Restricted stock and restricted stock units - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Number of Shares
Unvested beginning balance (in shares)	849,571
Granted (in shares)	336,096
Vested (in shares)	(174,723)
Cancelled/Forfeited (in shares)	(8,000)
Unvested ending balance (in shares)	1,002,944	849,571
Weighted Average Grant Date Fair Value
Unvested beginning balance (in dollars per share)	$ 15.12
Granted (in dollars per share)	62.25
Vested (in dollars per share)	23.30
Cancelled/Forfeited (in dollars per share)	21.38
Unvested ending balance (in dollars per share)	$ 29.44	$ 15.12
Fair value of restricted stock vested	$ 9.9	$ 4	$ 0.4

Stock Option Plans - Employee S

Stock Option Plans - Employee Stock Purchase Plan (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)shares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Shares purchased by employees under the employee stock purchase plan (in shares) | shares	214,025
Shares purchase by employees under the employee stock purchase plan | $	$ 6,578

Stock Option Plans - Stock Op58

Stock Option Plans - Stock Options Assumptions (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	6 months		6 years 3 months
Expected volatility	40.00%	45.00%	45.00%
Risk-free interest rate, minimum		1.56%	1.76%
Risk-free interest rate	48.00%
Risk-free interest rate, maximum		1.78%	2.02%
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 - Stock-base

Stock Option Plans - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 14,637	$ 7,271	$ 1,433
Cost of sales
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	1,132	316	267
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	1,020	444	96
Sales, general and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 12,485	$ 6,511	$ 1,070

Accumulated Other Comprehensi60

Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 232,522	$ (12,370)
Other comprehensive income before reclassifications:
Income tax effect—(expense) benefit	(38)	245
Net of tax	(2,568)	(1,597)
Amounts reclassified from accumulated other comprehensive loss to earnings:
Realized (gains) losses—marketable investments	(8)	540
Income tax effect—benefit (expense)	3	(194)
Net of tax	(5)	346
Net current-year other comprehensive income (loss)	(2,573)	(1,251)
Ending balance	266,547	232,522
Marketable Investments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(163)	(220)
Other comprehensive income before reclassifications:
OCI, before reclassifications, before tax, attributable to parent	98	(417)
Income tax effect—(expense) benefit	(35)	128
Net of tax	63	(289)
Amounts reclassified from accumulated other comprehensive loss to earnings:
Realized (gains) losses—marketable investments	(8)	540
Income tax effect—benefit (expense)	3	(194)
Net of tax	(5)	346
Net current-year other comprehensive income (loss)	58	57
Ending balance	(105)	(163)
Currency Translation Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(1,952)	(644)
Other comprehensive income before reclassifications:
OCI, before reclassifications, before tax, attributable to parent	(2,628)	(1,425)
Income tax effect—(expense) benefit	(3)	117
Net of tax	(2,631)	(1,308)
Amounts reclassified from accumulated other comprehensive loss to earnings:
Realized (gains) losses—marketable investments	0	0
Income tax effect—benefit (expense)	0	0
Net of tax	0	0
Net current-year other comprehensive income (loss)	(2,631)	(1,308)
Ending balance	(4,583)	(1,952)
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(2,115)	(864)
Amounts reclassified from accumulated other comprehensive loss to earnings:
Ending balance	$ (4,688)	$ (2,115)

Employee Benefit Plans Narrativ

Employee Benefit Plans Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Compensation and Retirement Disclosure [Abstract]
Employer contribution cost	$ 0.8	$ 0.3

Income Taxes - Income (Loss) be

Income Taxes - Income (Loss) before Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended							12 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
United States								$ (944)	$ 2,955	$ 2,230
Foreign								75	1,069	909
(Loss) Income before provision for (benefit from) income taxes	$ (1,092)	$ (383)	$ 2,121	$ 1,876	$ 2,084	$ (4,178)	$ 4,242	$ (869)	$ 4,024	$ 3,139

Income Taxes - Provision for (B

Income Taxes - Provision for (Benefit from) for Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended			12 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current:
Federal				$ (3,872)	$ 3,815	$ 1,155
State				304	603	274
Foreign				772	492	323
Total current				(2,796)	4,910	1,752
Deferred:
Federal				(11,909)	(3,025)	(625)
State				(785)	(251)	(116)
Foreign				(193)	25	(117)
Total deferred				(12,887)	(3,251)	(858)
Provision for (benefit from) income taxes	$ (12,998)	$ (3,396)	$ (170)	$ (15,683)	$ 1,659	$ 894

Income Taxes - Effective Income

Income Taxes - Effective Income Tax Reconciliation (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income tax at federal statutory rate	34.00%	34.00%	34.00%
State income taxes, net of federal benefit	75.90%	1.90%	3.20%
Foreign taxes differential	(63.00%)	(9.00%)	5.20%
Prepaid tax ASC 810-10	59.00%	2.10%	(8.90%)
IRC 199 deduction	(0.00%)	(7.40%)	(7.00%)
Stock-based compensation	1474.00%	14.80%	6.00%
Non- deductible meals and entertainment	(92.60%)	5.60%	5.80%
Imputed interest	(30.70%)	4.70%	6.60%
Tax credits	395.50%	(11.60%)	(12.10%)
Other	(47.40%)	3.60%	2.80%
Change in valuation allowance	0.30%	2.50%	(7.10%)
Effective tax rate	1805.00%	41.20%	28.50%

Income Taxes - Deferred Tax Ass

Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2014	Dec. 31, 2013
Deferred tax assets
Net operating loss carryforwards	$ 1,000	$ 5,983
Tax credits	1,355	6,260
Accruals and reserves	5,048	7,668
Stock-based compensation	1,352	3,703
Translation adjustment	715	690
UNICAP adjustments	3,840	4,721
Other	870	938
Gross deferred tax assets	14,180	29,963
Valuation allowance	(2,702)	(6,062)	$ (2,945)	$ (3,860)
Total deferred tax assets	11,478	23,901
Deferred tax liabilities
Depreciation and amortization	(1,335)	(1,425)
Total deferred tax liabilities	(1,335)	(1,425)
Net deferred tax assets	10,143	$ 22,476
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, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of valuation allowance
Balance at the beginning of the year	$ 2,702	$ 2,945	$ 3,860
Release of valuation allowance	0	(243)	(321)
Other reserves and deferrals	3,360	0	(594)
Balance at the end of the year	$ 6,062	$ 2,702	$ 2,945

Income Taxes - Operating Loss C

Income Taxes - Operating Loss Carryforwards (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)
Federal
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 10.7
Operating loss carryforwards, carryforward period	20 years
State
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 32.7
Foreign
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 1.3

Income Taxes - Tax Credit Carry

Income Taxes - Tax Credit Carryforwards (Details) - Research Tax Credit $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)
Federal
Tax Credit Carryforward [Line Items]
Tax credit carryforwards	$ 3.6
Period for which credits are carried forward	20 years
State
Tax Credit Carryforward [Line Items]
Tax credit carryforwards	$ 5

Income Taxes - Unrecognized Tax

Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Unrecognized tax benefits	$ 3,619	$ 1,726	$ 1,325	$ 3,827	$ 3,619	$ 1,726
Unrecognized tax benefits that would affect the effective tax rate if recognized				2,100
Reconciliation of the change in gross unrecognized tax benefits
Beginning balance	3,619	1,726	1,325
Gross increase for tax positions of current year	1,213	1,023	401
Gross increase for tax positions of prior years	250	1,062	0
Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions	(648)	0	0
Settlement	(387)	0	0
Lapse of statute of limitations	(220)	(192)	0
Ending balance	$ 3,827	$ 3,619	$ 1,726
Accrued interest and penalties related to uncertain tax positions				$ 100	$ 100	$ 0

Net Income (Loss) per Share o70

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
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Numerator
Net income	$ 11,906	$ 3,013	$ 2,291	$ 1,633	$ 901	$ (2,671)	$ 2,502	$ 14,814	$ 2,365	$ 2,245
Less: Deemed dividend paid to convertible preferred stockholders upon repurchase								0	0	(6,344)
Undistributed (income) loss attributable to preferred stockholders, basic								0	(1,281)	3,266
Net income (loss) attributable to common stockholders, basic	$ 11,906	$ 3,013	$ 2,291	$ 1,633	$ 276	$ (553)	$ 503	14,814	1,084	(833)
Net income (loss) attributable to common stockholders, diluted								$ 14,814	$ 1,084	$ (833)
Denominator
Weighted average shares used to compute net income (loss) per share attributable to common stockholders—Basic (in shares)	30,604,384	30,210,322	29,990,006	29,890,944	7,853,730	5,096,151	4,903,535	30,464,583	11,993,429	4,609,375
Weighted average shares used to compute net income (loss) per share attributable to common stockholders—Diluted (in shares)	33,755,383	33,308,193	33,023,495	32,321,410	10,189,248	5,096,151	7,193,452	33,478,078	14,219,650	4,609,375
Net income (loss) per share attributable to common stockholders—Basic (in dollars per share)	$ 0.39	$ 0.10	$ 0.08	$ 0.05	$ 0.04	$ (0.11)	$ 0.10	$ 0.49	$ 0.09	$ (0.18)
Net income (loss) per share attributable to common stockholders—Diluted (in dollars per share)	$ 0.35	$ 0.09	$ 0.07	$ 0.05	$ 0.03	$ (0.11)	$ 0.07	$ 0.44	$ 0.08	$ (0.18)
Stock Options
Denominator
Potential dilutive common stock securities, as calculated using treasury stock method (in shares)								3,013,495	2,226,221	0

Net Income (Loss) per Share o71

Net Income (Loss) per Share of Common Stock attributable to Common Stockholders - Antidilutive Securities (Details) - shares shares in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from the computation of earnings per share (in shares)	0.3	1.4	3.3

Geographic Areas and Product 72

Geographic Areas and Product Sales - Revenue by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended							12 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 67,187	$ 65,106	$ 57,919	$ 54,416	$ 50,416	$ 42,311	$ 38,952	$ 263,317	$ 186,095	$ 125,510
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue								176,104	127,311	82,965
Japan
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue								30,284	19,016	14,699
Other International
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue								$ 56,929	$ 39,768	$ 27,846

Geographic Areas and Product 73

Geographic Areas and Product Sales - Revenue by Product Category (Details) - USD ($) $ in Thousands	3 Months Ended							12 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue from External Customer [Line Items]
Revenue	$ 67,187	$ 65,106	$ 57,919	$ 54,416	$ 50,416	$ 42,311	$ 38,952	$ 263,317	$ 186,095	$ 125,510
Neuro
Revenue from External Customer [Line Items]
Revenue								185,533	141,410	106,242
Peripheral Vascular
Revenue from External Customer [Line Items]
Revenue								$ 77,784	$ 44,685	$ 19,268

Selected Quarterly Financial 74

Selected Quarterly Financial Data (Unaudited) - Selected Statement of Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue		$ 67,187	$ 65,106	$ 57,919	$ 54,416	$ 50,416	$ 42,311	$ 38,952	$ 263,317	$ 186,095	$ 125,510
Cost of revenue		24,313	23,636	18,014	17,958	16,919	14,936	12,224	92,488	62,037	42,668
Gross profit		42,874	41,470	39,905	36,458	33,497	27,375	26,728	170,829	124,058	82,842
Income (loss) before provision for (benefit from) income taxes		(1,092)	(383)	2,121	1,876	2,084	(4,178)	4,242	(869)	4,024	3,139
Provision for (benefit from) income taxes		(12,998)	(3,396)	(170)					(15,683)	1,659	894
Net income		11,906	3,013	2,291	1,633	901	(2,671)	2,502	14,814	2,365	2,245
Net (loss) income attributable to common stockholders		$ 11,906	$ 3,013	$ 2,291	$ 1,633	$ 276	$ (553)	$ 503	$ 14,814	$ 1,084	$ (833)
Net income (loss) per share attributable to common stockholders—Basic (in dollars per share)		$ 0.39	$ 0.10	$ 0.08	$ 0.05	$ 0.04	$ (0.11)	$ 0.10	$ 0.49	$ 0.09	$ (0.18)
Net income (loss) per share attributable to common stockholders—Diluted (in dollars per share)		$ 0.35	$ 0.09	$ 0.07	$ 0.05	$ 0.03	$ (0.11)	$ 0.07	$ 0.44	$ 0.08	$ (0.18)
Weighted average shares used to compute net income (loss) per share attributable to common stockholders—Basic (in shares)		30,604,384	30,210,322	29,990,006	29,890,944	7,853,730	5,096,151	4,903,535	30,464,583	11,993,429	4,609,375
Weighted average shares used to compute net income (loss) per share attributable to common stockholders—Diluted (in shares)		33,755,383	33,308,193	33,023,495	32,321,410	10,189,248	5,096,151	7,193,452	33,478,078	14,219,650	4,609,375
Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue	$ 73,105	$ 67,187	$ 65,106	$ 57,919
Cost of revenue	26,525	24,313	23,636	18,014
Gross profit	46,580	42,874	41,470	39,905
Income (loss) before provision for (benefit from) income taxes	(1,515)	(1,092)	(383)	2,121
Provision for (benefit from) income taxes	881	14	(568)	1,341
Net income	(2,396)	(1,106)	185	780
Net (loss) income attributable to common stockholders	$ (2,396)	$ (1,106)	$ 185	$ 780
Net income (loss) per share attributable to common stockholders—Basic (in dollars per share)	$ (0.08)	$ (0.04)	$ 0.01	$ 0.03
Net income (loss) per share attributable to common stockholders—Diluted (in dollars per share)	$ (0.08)	$ (0.04)	$ 0.01	$ 0.02
Weighted average shares used to compute net income (loss) per share attributable to common stockholders—Basic (in shares)	31,045,700	30,604,384	30,210,322	29,990,006
Weighted average shares used to compute net income (loss) per share attributable to common stockholders—Diluted (in shares)	31,045,700	30,604,384	32,693,684	32,486,516

Selected Quarterly Financial 75

Selected Quarterly Financial Data (Unaudited) - Selected Quarterly Cash Flow Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		9 Months Ended		12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Jun. 30, 2016	Jun. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net cash (used in) provided by operating activities	$ (2,074)	$ (2,662)	$ (8,182)	$ (8,331)	$ (2,450)	$ (11,374)	$ (12,807)	$ (20,689)	$ (6,389)
Net cash provided by (used in) financing activities	(1,513)	326	3,430	(2,974)	4,652	123,937	$ 7,126	$ 122,834	$ 42,897
Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net cash (used in) provided by operating activities	(3,584)	(2,662)	(12,555)	(8,331)	(10,051)	(12,631)
Net cash provided by (used in) financing activities	$ (3)	$ 326	$ 7,803	$ (2,974)	$ 12,253	$ 125,194

Selected Quarterly Financial 76

Selected Quarterly Financial Data (Unaudited) - Selected Balance Sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Prepaid expenses and other current assets	$ 18,727	$ 19,209	$ 17,371	$ 11,512	$ 9,352
Assets, Current	263,827	267,767	260,217	253,651	244,361
Deferred taxes	22,476	22,059	11,422	11,318	10,143
Other non-current assets	487				393
Total assets	308,254	306,488	283,944	275,121	263,848
Other non-current liabilities	824	5,540	4,199	3,094	1,667
Liabilities	41,707	42,884	36,388	37,073	31,326
Additional paid-in capital	273,865	267,429	262,276	253,988	252,087
Accumulated deficit	(2,661)	(264)	(12,171)	(15,184)	(17,475)
Total stockholders' equity	266,547	263,604	247,556	238,048	232,522	$ (12,370)	$ (8,062)
Total liabilities and stockholders' equity	$ 308,254	306,488	283,944	275,121	$ 263,848
Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Prepaid expenses and other current assets		18,665	17,406	11,512
Assets, Current		267,223	260,252	253,651
Deferred taxes		13,394	11,422	11,318
Total assets		297,279	283,979	275,121
Other non-current liabilities		6,081	4,199	3,094
Liabilities		43,425	36,388	37,073
Additional paid-in capital		275,031	266,650	255,499
Accumulated deficit		(17,616)	(16,510)	(16,695)
Total stockholders' equity		253,854	247,591	238,048
Total liabilities and stockholders' equity		$ 297,279	$ 283,979	$ 275,121