Entity Central Index Key Document and entity information. Document And Entity Information [Abstract] Document Type Document Type Amendment Flag Amendment Flag Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Trading Symbol Trading Symbol Entity Registrant Name Entity Registrant Name Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Well-known Seasoned Issuer Entity Well Known Seasoned Issuer Entity Current Reporting Status Entity Current Reporting Status Entity Voluntary Filers Entity Voluntary Filers Entity Filer Category Entity Filer Category Entity Common Stock, Shares Outstanding Entity Common Stock Shares Outstanding Entity Public Float Entity Public Float Statement Of Financial Position [Abstract] Assets Assets [Abstract] Current assets: Assets Current [Abstract] Cash and cash equivalents Cash And Cash Equivalents At Carrying Value Short-term investments Short Term Investments Restricted cash Restricted Cash And Cash Equivalents At Carrying Value Prepaid expenses and other current assets Prepaid Expense And Other Assets Current Total current assets Assets Current Property and equipment, net Property Plant And Equipment Net Restricted cash Restricted Cash And Cash Equivalents Noncurrent Long-term investments Long Term Investments Other assets Other Assets Noncurrent Total assets Assets Liabilities and Stockholders’ Equity Liabilities And Stockholders Equity [Abstract] Current liabilities: Liabilities Current [Abstract] Accounts payable Accounts Payable Current Accrued liabilities Accrued Liabilities Current Deferred rent—current portion Deferred Rent Credit Current Total current liabilities Liabilities Current Other liabilities Other Liabilities Noncurrent Total liabilities Liabilities Commitments and contingencies (Note 10) Commitments And Contingencies Stockholders’ equity: Stockholders Equity [Abstract] Preferred stock, par value of $0.001 per share—25,000,000 shares authorized; nil outstanding as of December 31, 2016 and 2015 Preferred Stock Value Common stock, par value of $0.001 per share—250,000,000 shares authorized; 41,240,230 and 38,882,394 shares issued and outstanding as of December 31, 2016 and 2015 Common Stock Value Additional paid-in capital Additional Paid In Capital Accumulated other comprehensive income (loss) Accumulated Other Comprehensive Income Loss Net Of Tax Accumulated deficit Retained Earnings Accumulated Deficit Total stockholders’ equity Stockholders Equity Total liabilities and stockholders’ equity Liabilities And Stockholders Equity Preferred stock, par value Preferred Stock Par Or Stated Value Per Share Preferred stock, shares authorized Preferred Stock Shares Authorized Preferred stock, shares outstanding Preferred Stock Shares Outstanding Common stock, par value Common Stock Par Or Stated Value Per Share Common stock, shares authorized Common Stock Shares Authorized Common stock, shares issued Common Stock Shares Issued Common stock, shares outstanding Common Stock Shares Outstanding Income Statement [Abstract] Revenue Sales Revenue Goods Net Operating expenses: Operating Expenses [Abstract] Research and development Research And Development Expense General and administrative General And Administrative Expense Total operating expenses Operating Expenses Loss from operations Operating Income Loss Other income (expense), net: Nonoperating Income Expense [Abstract] Interest income Investment Income Interest Other expense, net Other Nonoperating Income Expense Total other income (expense), net Nonoperating Income Expense Loss before income taxes Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest Income tax provision Income Tax Expense Benefit Net loss Net Income Loss Net loss attributable to common stockholders Net Income Loss Available To Common Stockholders Basic Net loss per share attributable to common stockholders, basic and diluted Earnings Per Share Basic And Diluted Shares used in computing net loss per share attributable to common stockholders, basic and diluted Weighted Average Number Of Share Outstanding Basic And Diluted Statement Of Income And Comprehensive Income [Abstract] Net loss Other comprehensive income (loss): Other Comprehensive Income Loss Net Of Tax Period Increase Decrease [Abstract] Foreign currency translation adjustments Other Comprehensive Income Foreign Currency Transaction And Translation Gain Loss Arising During Period Net Of Tax Unrealized gain (loss) on available-for-sale securities Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax Other comprehensive income (loss): Other Comprehensive Income Loss Net Of Tax Total comprehensive loss Comprehensive Income Net Of Tax Stock issued during period value secondary issues. Stock issued during period shares secondary issues. Stock issued during period value at market offering. Stock issued during period shares at market offering. Stock issued during period value for collaboration agreement. Stock issued during period shares for collaboration agreement. Adjustments to additional paid in capital put option grant for collaboration agreement. Adjustment to additional paid in capital and accumulated deficit to accretion on convertible preferred stock Statement Of Stockholders Equity [Abstract] Statement [Table] Statement [Table] Equity Components Statement Equity Components [Axis] Equity Component Equity Component [Domain] Common Stock Common Stock [Member] Additional Paid-in Capital Additional Paid In Capital [Member] Accumulated Other Comprehensive Income (Loss) Accumulated Other Comprehensive Income [Member] Accumulated Deficit Retained Earnings [Member] Class of Stock Statement Class Of Stock [Axis] Class of Stock Class Of Stock [Domain] Series A redeemable convertible preferred stock. Series A Redeemable Convertible Preferred Stock Series A Redeemable Convertible Preferred Stock [Member] Series b convertible preferred stock. Series B Convertible Preferred Stock Series B Convertible Preferred Stock [Member] Statement [Line Items] Statement [Line Items] Beginning balance Beginning balance, shares Beginning balance Temporary Equity Carrying Amount Attributable To Parent Beginning balance, shares Temporary Equity Shares Outstanding Accretion on convertible preferred stock Preferred Stock Accretion Of Redemption Discount Accretion on convertible preferred stock Adjustment To Additional Paid In Capital And Accumulated Deficit To Accretion On Convertible Preferred Stock Conversion of convertible preferred stock to common stock Stock Issued During Period Value Conversion Of Convertible Securities Conversion of convertible preferred stock to common stock, shares Stock Issued During Period Shares Conversion Of Convertible Securities Reclassification of preferred stock warrant liability Adjustments To Additional Paid In Capital Increase In Carrying Amount Of Redeemable Preferred Stock Issuance of common stock in connection with initial public offering, net of issuance costs and preferred stock dividend Stock Issued During Period Value New Issues Issuance of common stock in connection with initial public offering, net of issuance costs and preferred stock dividend, shares Stock Issued During Period Shares New Issues Issuance of common stock in connection with underwritten public offering, net of issuance costs Stock Issued During Period Value Secondary Issues Issuance of common stock in connection with underwritten public offering, net of issuance costs, shares Stock Issued During Period Shares Secondary Issues Issuance of common stock in connection with at-the-market offering, net of issuance costs Stock Issued During Period Value At Market Offering Issuance of common stock in connection with at-the-market offering, net of issuance costs, shares Stock Issued During Period Shares At Market Offering Issuance of common stock in connection with collaboration agreement, net of issuance costs Stock Issued During Period Value For Collaboration Agreement Issuance of common stock in connection with collaboration agreement, net of issuance costs, shares Stock Issued During Period Shares For Collaboration Agreement Put option grant in connection with collaboration agreement Adjustments To Additional Paid In Capital Put Option Grant For Collaboration Agreement Employee stock-based compensation Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value Issuance of common stock upon exercise of stock options and warrants Stock Issued During Period Value Stock Options Exercised Issuance of common stock upon exercise of stock options and warrants, shares Stock Issued During Period Shares Stock Options Exercised Restricted stock units vested during the period, net Adjustments To Additional Paid In Capital Share Based Compensation Restricted Stock Units Requisite Service Period Recognition Restricted stock units vested during the period, net of shares Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Vested In Period Other comprehensive income (loss) Ending balance Ending balance, shares Ending balance Ending balance, shares Non-cash license fee from collaboration arrangement. Proceeds from issuance of common stock at market offering. Statement Of Cash Flows [Abstract] Operating activities: Net Cash Provided By Used In Operating Activities Continuing Operations [Abstract] Adjustments to reconcile net loss to net cash used in operating activities: Adjustments Noncash Items To Reconcile Net Income Loss To Cash Provided By Used In Operating Activities [Abstract] Stock-based compensation Share Based Compensation Amortization of premium on investment securities, net Accretion Amortization Of Discounts And Premiums Investments Depreciation and amortization Depreciation Depletion And Amortization Revaluation of convertible preferred stock warrant liability Fair Value Adjustment Of Warrants Foreign currency remeasurement loss Foreign Currency Transaction Gain Loss Before Tax Non-cash license fee from collaboration arrangement Noncash License Fee From Collaboration Arrangement Changes in operating assets and liabilities: Increase Decrease In Operating Capital [Abstract] Prepaid expenses and other current assets Increase Decrease In Prepaid Deferred Expense And Other Assets Other assets Increase Decrease In Other Noncurrent Assets Accounts payable Increase Decrease In Accounts Payable Accrued liabilities and other liabilities Increase Decrease In Accrued Liabilities And Other Operating Liabilities Net cash used in operating activities Net Cash Provided By Used In Operating Activities Continuing Operations Investing activities: Net Cash Provided By Used In Investing Activities Continuing Operations [Abstract] Purchase of property and equipment Payments To Acquire Property Plant And Equipment Purchase of investments Payments To Acquire Available For Sale Securities Proceeds from sale of investments Proceeds From Sale Of Available For Sale Securities Proceeds from maturities of investments Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities Increase in restricted cash Increase In Restricted Cash Net cash provided by (used in) investing activities Net Cash Provided By Used In Investing Activities Continuing Operations Financing activities: Net Cash Provided By Used In Financing Activities Continuing Operations [Abstract] Proceeds from the issuance of common stock in connection with underwritten public offerings, net Proceeds From Issuance Of Common Stock Proceeds from the issuance of common stock in connection with at-the-market offering, net Proceeds From Issuance Of Common Stock At Market Offering Proceeds from the issuance of common stock in connection with collaboration agreement, net Proceeds From Issuance Of Private Placement Proceeds from the issuance of common stock from equity awards, net Proceeds From Issuance Of Shares Under Incentive And Share Based Compensation Plans Including Stock Options Payment of preferred stock dividend Payments Of Dividends Preferred Stock And Preference Stock Net cash provided by financing activities Net Cash Provided By Used In Financing Activities Continuing Operations Effect of exchange rate changes on cash Effect Of Exchange Rate On Cash Continuing Operations Net increase in cash and cash equivalents Cash And Cash Equivalents Period Increase Decrease Cash and cash equivalents at beginning of year Cash and cash equivalents at end of year Supplemental disclosures of non-cash investing and financing information: Cash Flow Noncash Investing And Financing Activities Disclosure [Abstract] Costs of property and equipment included in accounts payable and accrued liabilities Capital Expenditures Incurred But Not Yet Paid Tenant improvement allowance Payments For Tenant Improvements Reclassification of warrant liability to equity upon conversion to common stock warrants Embedded Derivative No Longer Bifurcated Amount Reclassified To Stockholders Equity Conversion of Series A and Series B preferred stock to common stock Conversion Of Stock Amount Converted1 Organization Consolidation And Presentation Of Financial Statements [Abstract] Organization and Basis of Presentation Organization Consolidation Basis Of Presentation Business Description And Accounting Policies [Text Block] Accounting Policies [Abstract] Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Fair Value Disclosures [Abstract] Fair Value Measurements Fair Value Disclosures [Text Block] Investments Debt And Equity Securities [Abstract] Balance Sheet Components Supplemental Balance Sheet Disclosures [Text Block] Collaborative arrangement and noncollaborative arrangement transactions disclosure. Research grant agreement. Research Grant Agreement [Abstract] License and Research Agreements Collaborative Arrangement And Noncollaborative Arrangement Transactions Disclosure [Text Block] Equity [Abstract] Equity Stockholders Equity Note Disclosure [Text Block] Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] Stock-Based Awards Disclosure Of Compensation Related Costs Share Based Payments [Text Block] Defined Contribution Pension And Other Postretirement Plans Disclosure [Abstract] Defined Contribution Plan Compensation And Employee Benefit Plans [Text Block] Income Tax Disclosure [Abstract] Income Taxes Income Tax Disclosure [Text Block] Commitments And Contingencies Disclosure [Abstract] Commitments and Contingencies Commitments And Contingencies Disclosure [Text Block] Earnings Per Share [Abstract] Net Loss per Share Attributable to Common Stockholders Earnings Per Share [Text Block] Accumulated Other Comprehensive Income (Loss) Comprehensive Income Note [Text Block] Quarterly Financial Data [Abstract] Quarterly Financial Data (unaudited) Quarterly Financial Information [Text Block] Basis of Consolidation Consolidation Policy [Text Block] Use of Estimates Use Of Estimates Cash and Cash Equivalents Cash And Cash Equivalents Policy [Text Block] Investments Investment Policy [Text Block] Concentration of credit risk and other risks and uncertainties. Concentration of Credit Risk and Other Risks and Uncertainties Concentration Of Credit Risk And Other Risks And Uncertainties Policy [Text Block] Property and Equipment Property Plant And Equipment Policy [Text Block] Impairment of Long-Lived Assets Impairment Or Disposal Of Long Lived Assets Policy [Text Block] Restricted Cash Cash And Cash Equivalents Restricted Cash And Cash Equivalents Policy Accruals of research and development costs. Accruals of Research and Development Costs Accruals Of Research And Development Costs Policy [Text Block] Revenue Revenue Recognition Policy [Text Block] Leases Lease Policy [Text Block] Comprehensive Loss Comprehensive Income Policy Policy [Text Block] Research and Development Research And Development Expense Policy Stock-Based Compensation Share Based Compensation Option And Incentive Plans Policy Income Taxes Income Tax Policy [Text Block] Foreign Currency Foreign Currency Transactions And Translations Policy [Text Block] Net Loss per Share Attributable to Common Stockholders Earnings Per Share Policy [Text Block] Recent Accounting Pronouncements New Accounting Pronouncements Policy Policy [Text Block] Property plant and equipment useful lives. Summary of Useful Lives of Property and Equipment Property Plant And Equipment Useful Lives Table [Text Block] Summary of Financial Assets Measured on Recurring Basis Fair Value Assets Measured On Recurring Basis [Text Block] Summary of Fair Values of Cash Equivalents, Short-Term Investments and Long-Term Investments Classified as Available-for-Sale Securities Schedule Of Cash Cash Equivalents And Short Term Investments Table [Text Block] Summary of Property and Equipment Property Plant And Equipment [Text Block] Accrued Liabilities Schedule Of Accrued Liabilities Table [Text Block] Summary of Activity Under Stock Option Plans Including 2011 Plan and 2014 Plan Schedule Of Share Based Compensation Stock Options Activity Table [Text Block]