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 Convertible preferred stock warrant liability. Liabilities related to early exercise of options. Statement Of Financial Position [Abstract] Assets Assets [Abstract] Current assets: Assets Current [Abstract] Cash and cash equivalents Cash And Cash Equivalents At Carrying Value Accounts receivable Accounts Receivable Net Current 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 Other assets Other Assets Noncurrent Restricted cash Restricted Cash And Cash Equivalents Noncurrent Total assets Assets Liabilities, convertible preferred stock, and stockholders’ equity (deficit) Liabilities And Stockholders Equity [Abstract] Current liabilities: Liabilities Current [Abstract] Accounts payable Accounts Payable Current Accrued compensation and benefits Employee Related Liabilities Current Accrued and other liabilities Accrued Liabilities And Other Liabilities Deferred revenue, current portion Deferred Revenue Current Total current liabilities Liabilities Current Other long-term liabilities Other Liabilities Noncurrent Deferred revenue, non-current Deferred Revenue Noncurrent Convertible preferred stock warrant liability Convertible Preferred Stock Warrant Liability Liabilities related to early exercise of options Liabilities Related To Early Exercise Of Options Total liabilities Liabilities Commitments and contingencies (Note 12) Commitments And Contingencies Convertible preferred stock, $0.0001 par value per share—no shares and 108,829,748 shares authorized as of December 31, 2014 and 2013, respectively; no shares and 11,517,222 shares issued and outstanding as of December 31, 2014 and 2013, respectively Temporary Equity Carrying Amount Attributable To Parent Stockholders’ equity (deficit): Stockholders Equity [Abstract] Preferred stock, $0.0001 par value; 5,000,000 shares and no shares authorized as of December 31, 2014 and 2013, respectively; no shares issued and outstanding as of December 31, 2014 and 2013 Preferred Stock Value Common stock, $0.0001 par value per share—300,000,000 and 130,360,121 shares authorized as of December 31, 2014 and 2013, respectively; 18,589,245 and 1,225,481 shares issued and outstanding as of December 31, 2014 and 2013, respectively Common Stock Value Additional paid-in capital Additional Paid In Capital Common Stock Accumulated deficit Retained Earnings Accumulated Deficit Total stockholders’ equity (deficit) Stockholders Equity Total liabilities, convertible preferred stock, and stockholders’ equity (deficit) Liabilities And Stockholders Equity Convertible preferred stock, par value Temporary Equity Par Or Stated Value Per Share Convertible preferred stock, shares authorized Temporary Equity Shares Authorized Convertible preferred stock, shares issued Temporary Equity Shares Issued Convertible preferred stock, shares outstanding Temporary Equity Shares Outstanding Preferred stock, par value Preferred Stock Par Or Stated Value Per Share Preferred stock, shares authorized Preferred Stock Shares Authorized Preferred stock, shares issued Preferred Stock Shares Issued 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: Revenues [Abstract] Licensing revenue Licenses Revenue Collaborative development revenue Revenue From Related Parties Total revenue Revenues 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 Other Nonoperating Income Expense Change in fair value of preferred stock warrant liability Fair Value Adjustment Of Warrants Loss before provision for income taxes Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest Provision for income taxes Income Tax Expense Benefit Net loss and comprehensive loss Net Income Loss Net loss per common share, basic and diluted Earnings Per Share Basic And Diluted Shares used to compute net loss per common share, basic and diluted Weighted Average Number Of Share Outstanding Basic And Diluted Reclassification of warrant liability to additional paid-in capital upon completion of initial public offering. Net exercise and conversion of preferred stock warrants to common stock in connection with initial public offering in shares. 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 Deficit Retained Earnings [Member] Class of Stock Statement Class Of Stock [Axis] Class of Stock Class Of Stock [Domain] Convertible Preferred Stock Convertible Preferred Stock [Member] Statement [Line Items] Statement [Line Items] Balance, amount Balance, shares Shares Outstanding Conversion of convertible preferred stock to common stock in connection with initial public offering, amount Stock Issued During Period Value Conversion Of Convertible Securities Conversion of convertible preferred stock to common stock in connection with initial public offering, shares Stock Issued During Period Shares Conversion Of Convertible Securities Net exercise and conversion of preferred stock warrants to common stock in connection with initial public offering, amount Reclassification Of Warrant Liability To Additional Paid In Capital Upon Completion Of Initial Public Offering Net exercise and conversion of preferred stock warrants to common stock in connection with initial public offering, shares Net Exercise And Conversion Of Preferred Stock Warrants To Common Stock In Connection With Initial Public Offering Shares Exercise of stock options and vesting of early exercised stock options, net of repurchases, amount Stock Issued During Period Value Stock Options Exercised Exercise of stock options and vesting of early exercised stock options, net of repurchases, shares Stock Issued During Period Shares Stock Options Exercised Issuance of common stock in connection with initial public offering, net of offering costs, amount Stock Issued During Period Value New Issues Issuance of common stock in connection with initial public offering, net of offering costs, shares Stock Issued During Period Shares New Issues Issuance of common stock for services, amount Stock Issued During Period Value Issued For Services Issuance of common stock for services, shares Stock Issued During Period Shares Issued For Services Stock-based compensation Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value Net loss Balance, amount Balance, shares Reclassification of convertible preferred warrant liability to additional paid-in capital. 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 provided by operating activities: Adjustments To Reconcile Net Income Loss To Cash Provided By Used In Operating Activities [Abstract] Depreciation and amortization expense Depreciation And Amortization Stock-based compensation Share Based Compensation Change in fair value of preferred stock warrant liability Changes in operating assets and liabilities: Increase Decrease In Operating Capital [Abstract] Accounts receivable Increase Decrease In Accounts Receivable Prepaid expenses and other assets Increase Decrease In Prepaid Deferred Expense And Other Assets Accounts payable Increase Decrease In Accounts Payable Accrued compensation and benefits Increase Decrease In Employee Related Liabilities Accrued and other liabilities Increase Decrease In Other Accrued Liabilities Deferred revenue Increase Decrease In Deferred Revenue Other long-term liabilities Increase Decrease In Other Operating Liabilities Net cash provided by 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] Purchases of property and equipment Payments To Acquire Property Plant And Equipment Net cash 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 issuance of common stock upon initial public offering, net Proceeds From Issuance Of Common Stock Proceeds from issuance of common stock from exercise of options, including early exercise of stock options Proceeds From Stock Options Exercised Repurchase of unvested common stock Payments For Repurchase Of Common Stock Net cash provided by (used in) financing activities Net Cash Provided By Used In Financing Activities Continuing Operations Net increase in cash and cash equivalents Cash And Cash Equivalents Period Increase Decrease Cash and cash equivalents at beginning of period Cash and cash equivalents at end of period Supplementary disclosure of cash flow information Supplemental Cash Flow Information [Abstract] Income taxes paid Income Taxes Paid Net Supplementary disclosure of non-cash financing information: Cash Flow Noncash Investing And Financing Activities Disclosure [Abstract] Services settled through the issuance of common stock Stock Issued1 Reclassification of convertible preferred warrant liability to additional paid-in capital Reclassification Of Convertible Preferred Warrant Liability To Additional Paid In Capital Conversion of convertible preferred stock to common stock at closing of initial public offering 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] Property Plant And Equipment [Abstract] Property and Equipment Property Plant And Equipment Disclosure [Text Block] Collaboration and licensing agreements. Collaboration And Licensing Agreements [Abstract] Collaboration and Licensing Agreements Collaborative Arrangement Disclosure [Text Block] The entire disclosure for terms, amounts, nature of changes, rights and privileges, dividends, and other matters related to convertible preferred stock. Class Of Stock Disclosures [Abstract] Convertible Preferred Stock Convertible Preferred Stock [Text Block] Preferred Stock Warrants Preferred Stock [Text Block] Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] Equity Incentive Plans Disclosure Of Compensation Related Costs Share Based Payments [Text Block] Income Tax Disclosure [Abstract] Income Taxes Income Tax Disclosure [Text Block] Earnings Per Share [Abstract] Net Loss per Share Earnings Per Share [Text Block] Related Party Transactions [Abstract] Schedule Of Related Party Transactions By Related Party [Table] Schedule Of Related Party Transactions By Related Party [Table] Related Party Transaction Related Party Transaction [Axis] Related Party Transaction Related Party Transaction [Domain] Clinical Operations Consulting Arrangement [Member] Clinical Operations Consulting Arrangement Clinical Operations Consulting Arrangement [Member] Related Party Related Party Transactions By Related Party [Axis] Related Party Related Party [Domain] Executive Officer Spouse [Member] Spouse of Executive Officer Executive Officer Spouse [Member] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Related Party Transactions Related Party Transactions Disclosure [Text Block] Commitments And Contingencies Disclosure [Abstract] Commitments and Contingencies Commitments And Contingencies Disclosure [Text Block] Quarterly Financial Information Disclosure [Abstract] Selected Quarterly Financial Data (Unaudited) Quarterly Financial Information [Text Block] Subsequent Events [Abstract] Subsequent Events Subsequent Events [Text Block] Use of Estimates Use Of Estimates Cash and Cash Equivalents Cash And Cash Equivalents Policy [Text Block] Restricted Cash Cash And Cash Equivalents Restricted Cash And Cash Equivalents Policy Concentration of Credit Risk Concentration Risk Credit Risk Fair Value of Financial Instruments Fair Value Of Financial Instruments Policy 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] Income Taxes Income Tax Policy [Text Block] Revenue Recognition Revenue Recognition Policy [Text Block] Stock-Based Compensation Compensation Related Costs Policy [Text Block] Research and Development Costs Research And Development Expense Policy Convertible preferred stock warrant liability. Convertible Preferred Stock Warrant Liability Convertible Preferred Stock Warrant Liability Policy [Text Block] Comprehensive Loss Comprehensive Income Policy Policy [Text Block] Net Loss per Share Earnings Per Share Policy [Text Block] Recent Accounting Pronouncements New Accounting Pronouncements Policy Policy [Text Block] Summary of Fair Value Measurements of Company's Financial Assets and Liabilities Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Table [Text Block] Summary of Changes in Estimated Fair Value of Preferred Stock Warrant Liability Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Text Block] Summary of Property and Equipment Property Plant And Equipment [Text Block] Summary of Convertible Preferred Stock Schedule Of Stock By Class [Text Block] Plan Name Plan Name [Axis] Plan Name Plan Name [Domain] Two thousand fourteen employee stock purchase plan. 2014 Employee Stock Purchase Plan Two Thousand Fourteen Employee Stock Purchase Plan [Member] Summary of Activity Under 2008 Plan and 2014 Plan, Including Grants to Nonemployees and Restricted Stock Issued Schedule Of Share Based Compensation Activity Table [Text Block] Summary of Weighted Average Assumptions to Estimate Fair Value of Stock Option Awards and Employee Stock Purchase Plan Schedule Of Share Based Payment Award Stock Options Valuation Assumptions Table [Text Block] Summary of Stock-Based Compensation Recognized Schedule Of Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Text Block] Reconciliation of Statutory Federal Income Tax Rate to the Company's Effective Tax Rate Schedule Of Effective Income Tax Rate Reconciliation Table [Text Block] Significant Components of the Company's Deferred Tax Assets Schedule Of Deferred Tax Assets And Liabilities Table [Text Block] Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits Schedule Of Unrecognized Tax Benefits Roll Forward Table [Text Block] Computation of Net Loss Per Common Share Schedule Of Earnings Per Share Basic And Diluted Table [Text Block] Calculation of Anti-dilutive Potentially Dilutive Securities Not Included in Diluted Per Share Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share [Text Block] Schedule of Future Minimum Payments Under the Noncancelable Operating Lease Schedule Of Future Minimum Rental Payments For Operating Leases Table [Text Block] Schedule of Selected Quarterly Financial Results from Operations Schedule Of Quarterly Financial Information Table [Text Block] Organization and basis of presentation. Organization and basis of presentation. Organization And Basis Of Presentation [Table] Organization And Basis Of Presentation [Table] Sale of Stock Subsidiary Sale Of Stock [Axis] Sale of Stock Sale Of Stock Name Of Transaction [Domain] IPO I P O [Member] Organization And Basis Of Presentation [Line Items] Organization And Basis Of Presentation [Line Items] Date of incorporation Entity Incorporation Date Of Incorporation Place of incorporation Entity Incorporation State Country Name Number of operating segments Number Of Operating Segments Reverse stock split, description Stockholders Equity Reverse Stock Split Reverse stock split ratio Stockholders Equity Note Stock Split Conversion Ratio1 Additional common stock issued on exercise of option by underwriters. Stock issued during period, shares, new issues Additional common stock issued on exercise of option by Underwriters Additional Common Stock Issued On Exercise Of Option By Underwriters Net proceeds from the IPO Proceeds From Issuance Initial Public Offering Underwriting discounts and commissions and expenses Expense Related To Distribution Or Servicing And Underwriting Fees Convertible preferred stock converted to common stock, shares Conversion Of Stock Shares Converted1 Convertible preferred stock converted to common stock, value Shares authorized Capital Units Authorized Cash and cash equivalents original maturity dates. Restricted Cash and Cash Equivalents Restricted Cash And Cash Equivalents Cash And Cash Equivalents [Axis] Cash and Cash Equivalents Restricted Cash And Cash Equivalents Cash And Cash Equivalents [Member] Certificate of Deposit Certificates Of Deposit [Member] Range Range [Axis] Range Range [Member] Minimum Minimum [Member] Maximum Maximum [Member] Cash and cash equivalents original maturity dates Cash And Cash Equivalents Original Maturity Dates Property and equipment, estimated useful lives Property Plant And Equipment Useful Life Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Table] Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Table] Asset Class Fair Value By Asset Class [Axis] Asset Class Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation By Asset Class [Domain] Money Market Funds Money Market Funds [Member] Measurement Frequency Fair Value By Measurement Frequency [Axis] Fair Value, Measurement Frequency Fair Value Measurement Frequency [Domain] Fair Value, Recurring Fair Value Measurements Recurring [Member] Fair Value, Hierarchy Fair Value By Fair Value Hierarchy Level [Axis] Fair Value Hierarchy Fair Value Measurements Fair Value Hierarchy [Domain] Level 1 Fair Value Inputs Level1 [Member] Level 2 Fair Value Inputs Level2 [Member] Level 3 Fair Value Inputs Level3 [Member] Liability Class Fair Value By Liability Class [Axis] Fair Value by Liability Class Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation By Liability Class [Domain] Convertible preferred stock warrant liability. Convertible preferred stock warrant liability Convertible Preferred Stock Warrant Liability [Member] Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] Assets: Assets Fair Value Disclosure [Abstract] Assets at fair value Assets Fair Value Disclosure Liabilities: Liabilities Fair Value Disclosure [Abstract] Liabilities at fair value Liabilities Fair Value Disclosure Fair value of preferred stock warrant liability, probability of initial public offering scenario, percentage. Fair value of preferred stock warrant liability, probability of merger scenario, percentage. Fair value of preferred stock warrant liability, probability of stay private scenario, percentage. Fair value of preferred stock warrant liability, probability of IPO scenario, percentage Fair Value Of Preferred Stock Warrant Liability Probability Of Initial Public Offering Scenario Percentage Fair value of preferred stock warrant liability, probability of merger scenario, percentage Fair Value Of Preferred Stock Warrant Liability Probability Of Merger Scenario Percentage Fair value of preferred stock warrant liability, probability of stay private scenario, percentage Fair Value Of Preferred Stock Warrant Liability Probability Of Stay Private Scenario Percentage Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Table] Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Table] Preferred stock warrant liability. Preferred stock warrant liability Preferred Stock Warrant Liability [Member] Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] Beginning balance Fair Value Measurement With Unobservable Inputs Reconciliations Recurring Basis Liability Value Net increase in fair value of warrant liabilities upon revaluation Reclassification of warrant liability to additional paid-in capital upon completion of IPO Ending balance Schedule Of Property Plant And Equipment [Table] Schedule Of Property Plant And Equipment [Table] Property, Plant and Equipment, Type Property Plant And Equipment By Type [Axis] Property, Plant and Equipment, Type Property Plant And Equipment Type [Domain] Laboratory equipment. Laboratory Equipment Laboratory Equipment [Member] Office equipment and furniture. Office Equipment and Furniture Office Equipment And Furniture [Member] Construction in Progress Construction In Progress [Member] Leasehold Improvements Leasehold Improvements [Member] Property Plant And Equipment [Line Items] Property Plant And Equipment [Line Items] Property and equipment, gross Property Plant And Equipment Gross Less: accumulated depreciation and amortization Accumulated Depreciation Depletion And Amortization Property Plant And Equipment Total property and equipment, net Royalties payable percentage. Period for exercise of right. Deferred Revenue Disclosure [Abstract] Revenue Recognition Multiple Deliverable Arrangements [Table] Revenue Recognition Multiple Deliverable Arrangements [Table] Counterparty Name Counterparty Name [Axis] Counterparty Name Repurchase Agreement Counterparty Name [Domain] AstraZeneca. AstraZeneca Astra Zeneca [Member] Research and Development Arrangement, Contract to Perform for Others, Type Research And Development Arrangement Contract To Perform For Others By Type [Axis] Research and Development Arrangement, Contract to Perform for Others, Type Research And Development Arrangement Contract To Perform For Others Type [Domain] First phase three clinical development program. First Phase 3 Clinical Development Program First Phase Three Clinical Development Program [Member] Type of Arrangement and Non-arrangement Transactions Type Of Arrangement [Axis] Arrangements and Non-arrangement Transactions Arrangements And Nonarrangement Transactions [Member] Funding agreement one. Funding Agreement One Funding Agreement One [Member] Funding agreement two. Funding Agreement Two Funding Agreement Two [Member] Funding agreement three. Funding Agreement Three Funding Agreement Three [Member] Deferred Revenue Arrangement Type Deferred Revenue Arrangement Type [Axis] Deferred Revenue Deferred Revenue Arrangement Type [Domain] Future development milestones. Future Development Milestones Future Development Milestones [Member] Launch, commercialization and sales milestones. Launch, Commercialization, and Sales Milestones Launch Commercialization And Sales Milestones [Member] Amortization of up-front and other license fees. Amortization of Up-Front and Other License Fees Amortization Of Up Front And Other License Fees [Member] Collaborative Development Services Collaborative Development Services Collaborative Development Services [Member] Sanofi. Sanofi Sanofi [Member] Revenue Recognition Multiple Deliverable Arrangements [Line Items] Revenue Recognition Multiple Deliverable Arrangements [Line Items] Co-funding amount License Costs Royalties payable percentage Royalties Payable Percentage Exercise of right, limited period Period For Exercise Of Right Deferred Revenue, Additions Deferred Revenue Additions Future potential payments to be received. Future potential payments to be received Future Potential Payments To Be Received Revenue recognized Deferred Revenue Revenue Recognized Deferred revenue Deferred Revenue Patent costs under responsibility of the company Cost Of Services Licenses And Services Schedule Of Stock By Class [Table] Schedule Of Stock By Class [Table] Class Of Stock [Line Items] Class Of Stock [Line Items] Temporary equity shares issued and outstanding. Series A convertible preferred stock . Series A Convertible Preferred Stock Series A Convertible Preferred Stock [Member] Series B convertible preferred stock. Series B Convertible Preferred Stock Series B Convertible Preferred Stock [Member] Convertible Preferred Stock Shares Authorized Convertible Preferred Stock Shares Issued and Outstanding Temporary Equity Shares Issued And Outstanding Convertible Preferred Stock Net Carrying Value Convertible Preferred Stock Aggregate Liquidation Preference Temporary Equity Liquidation Preference Company issued warrants Convertible Preferred Stock Shares Issued Upon Conversion Exercise price of the warrants Class Of Warrant Or Right Exercise Price Of Warrants Or Rights1 Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table] Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table] Subsequent Event Type Subsequent Event Type [Axis] Subsequent Event Type Subsequent Event Type [Domain] Subsequent Event Subsequent Event [Member] Award Type Award Type [Axis] Equity Award Share Based Compensation Arrangements By Share Based Payment Award Award Type And Plan Name [Domain] Two​ thousand​ eight​ equity incentive award. Two Thousand Eight Equity Incentive Award Two Thousand Eight Equity Incentive Award [Member] Two thousand fourteen equity incentive award plan. 2014 Equity Incentive Award Plan Two Thousand Fourteen Equity Incentive Award Plan [Member] Two thousand eight stock incentive plan. 2008 Stock Incentive Plan Two Thousand Eight Stock Incentive Plan [Member] Restricted Stock Restricted Stock [Member] Employees Stock Option Employee Stock Option [Member] Nonemployees stock option member. Nonemployees Stock Option Nonemployees Stock Option [Member] Share Based Compensation Arrangement By Share Based Payment Award [Line Items] Share Based Compensation Arrangement By Share Based Payment Award [Line Items] Vesting period Share Based Compensation Arrangement By Share Based Payment Award Award Vesting Period1 Increase in shares reserved for issuance, maximum shares to be issued up on exercise of stock options. Common stock reserved Deferred Compensation Arrangement With Individual Common Stock Reserved For Future Issuance Increase in shares reserved for issuance, maximum shares to be issued up on exercise of stock options Increase In Shares Reserved For Issuance Maximum Shares To Be Issued Up On Exercise Of Stock Options Possible increase in shares reserved for issuance as percentage of outstanding stock Share Based Compensation Arrangement By Share Based Payment Award Percentage Of Outstanding Stock Maximum Share based compensation arrangement by share based payment award number of shares available for grant options authorized. Share based compensation arrangement by share based payment award number of shares available for grant options exercised in period. Share based compensation arrangement by share based payment award number of shares available for grant options repurchased. Share based compensation arrangement by share based payment award number of shares available for grant issuance of common stock for services. Shares Available for Grant Share Based Compensation Arrangement By Share Based Payment Award Additional General Disclosures [Abstract] Shares Available for Grant, Beginning balance Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Available For Grant Shares Available for Grant, Options authorized Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Available For Grant Options Authorized Shares Available for Grant, Options granted Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross Shares Available for Grant, Options exercised Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Available For Grant Options Exercised In Period Shares Available for Grant, Options canceled Stock Issued During Period Shares Share Based Compensation Forfeited Shares Available for Grant, Options repurchased Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Available For Grant Options Repurchased Shares Available for Grant, Issuance of common stock for services Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Available For Grant Issuance Of Common Stock For Services Shares Available for Grant, Ending balance Shares Available for Grant, Issuance of common stock for services Share based compensation arrangement by share based payment award options authorized in period gross. Share based compensation arrangement by share based payment award options repurchased in period gross. Share based compensation arrangement by share based payment award options issuance of common stock for services in period gross. Share based compensation arrangement by share based payment award options expected to vest. Options Issued and Outstanding Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Roll Forward Options Issued and Outstanding Number of Shares, Beginning balance Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number Options Issued and Outstanding Number of Shares, Options authorized Share Based Compensation Arrangement By Share Based Payment Award Options Authorized In Period Gross Options Issued and Outstanding Number of Shares, Options granted Options Issued and Outstanding Number of Shares, Options exercised Options Issued and Outstanding Number, Options cancelled Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period Options Issued and Outstanding Number of Shares, Options repurchased Share Based Compensation Arrangement By Share Based Payment Award Options Repurchased In Period Gross Options Issued and Outstanding Number of Shares, Issuance of common stock for services Share Based Compensation Arrangement By Share Based Payment Award Options Issuance Of Common Stock For Services In Period Gross Options Issued and Outstanding Number of Shares, Ending balance Options Issued and Outstanding Number of Shares, Expected to vest Share Based Compensation Arrangement By Share Based Payment Award Options Expected To Vest Options Issued and Outstanding Number of Shares, Vested Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number Share based compensation arrangements by share based payment award options repurchased in period weighted average exercise price. Share based compensation arrangements by share based payment award options issuance of common stock for services in period weighted average exercise price. Share based compensation arrangement by share based payment award options expected to vest weighted average exercise price. Options Issued and Outstanding Weighted Average Exercise Price per Share Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price Rollforward Options Issued and Outstanding Weighted Average Exercise Price per Share, Beginning balance Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price Options Issued and Outstanding Weighted Average Exercise Price per Share, Options granted Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price Options Issued and Outstanding Weighted Average Exercise Price per Share, Options exercised Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price Options Issued and Outstanding Weighted Average Exercise Price per Share, Options canceled Share Based Compensation Arrangements By Share Based Payment Award Options Forfeitures In Period Weighted Average Exercise Price Options Issued and Outstanding Weighted Average Exercise Price per Share, Options repurchased Share Based Compensation Arrangements By Share Based Payment Award Options Repurchased In Period Weighted Average Exercise Price Options Issued and Outstanding Weighted Average Exercise Price per Share, Issuance of common stock for services Share Based Compensation Arrangements By Share Based Payment Award Options Issuance Of Common Stock For Services In Period Weighted Average Exercise Price Options Issued and Outstanding Weighted Average Exercise Price per Share, Ending balance Options Issued and Outstanding Weighted Average Exercise Price per Share, Expected to vest Share Based Compensation Arrangement By Share Based Payment Award Options Expected To Vest Weighted Average Exercise Price Options Issued and Outstanding Weighted Average Exercise Price per Share, Vested Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price Share based compensation arrangement by share based payment award options expected to vest intrinsic value. Aggregate Intrinsic Value Share Based Compensation Arrangement By Share Based Payment Award Options Additional Disclosures [Abstract] Aggregate Intrinsic Value, Ending balance Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value Aggregate Intrinsic Value, Expected to Vest Share Based Compensation Arrangement By Share Based Payment Award Options Expected To Vest Intrinsic Value Aggregate Intrinsic Value, Vested Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Intrinsic Value1 Weighted-average grant-date estimated fair value of options granted Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Weighted Average Grant Date Fair Value Estimated fair value of common stock Fair Value Assumptions Exercise Price Employee stock purchase plan initial offering period commenced period. Employee stock purchase plan initial offering period ending period. Employee stock purchase plan initial offering commenced period Employee Stock Purchase Plan Initial Offering Period Commenced Period Employee stock purchase plan initial offering ending period Employee Stock Purchase Plan Initial Offering Period Ending Period Shares available for future grant Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions And Methodology [Abstract] Schedule Of Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Table] Schedule Of Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Table] Expected term (years) Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Expected Term1 Volatility Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate Risk-free interest rate Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Risk Free Interest Rate Dividend yield Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate Stock repurchase price. Common stock outstanding subject to repurchase Stock Repurchase Program Remaining Number Of Shares Authorized To Be Repurchased Repurchase price of common stock Stock Repurchase Price Share-based award accelerated vesting number of shares Sharebased Compensation Arrangement By Sharebased Payment Award Accelerated Vesting Number Stock-based compensation charge Sharebased Compensation Arrangement By Sharebased Payment Award Compensation Cost1 Income Statement Location Income Statement Location [Axis] Income Statement Location Income Statement Location [Domain] Research and Development Research And Development Expense [Member] General and Administrative General And Administrative Expense [Member] Unrecognized stock based compensation expense Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Unrecognized stock based compensation expense, weighted-average remaining recognition period Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Period For Recognition1 Issuance of common stock for services (Shares) Expected income tax provision at the federal statutory rate Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate State taxes, net of federal benefit Effective Income Tax Rate Reconciliation State And Local Income Taxes Change in valuation allowance Effective Income Tax Rate Reconciliation Change In Deferred Tax Assets Valuation Allowance Nondeductible expenses Effective Income Tax Rate Reconciliation Nondeductible Expense Tax credits Effective Income Tax Rate Reconciliation Tax Credits Other Effective Income Tax Rate Reconciliation Other Adjustments Income tax provision Effective Income Tax Rate Continuing Operations Deferred tax assets: Deferred Tax Assets Net [Abstract] Net operating loss carryforwards Deferred Tax Assets Operating Loss Carryforwards Deferred revenue Deferred Tax Assets Deferred Income Research credits Deferred Tax Assets Tax Credit Carryforwards Research Other Deferred Tax Assets Other Gross deferred tax assets Deferred Tax Assets Gross Valuation allowance Deferred Tax Assets Valuation Allowance Total deferred tax assets Deferred Tax Assets Net Deferred tax liabilities Deferred Tax Liabilities Net deferred tax assets Deferred Tax Assets Liabilities Net Income tax disclosure. Income tax disclosure. Income Tax Disclosure [Table] Income Tax Disclosure [Table] Income Tax Authority Income Tax Authority [Axis] Income Tax Authority Income Tax Authority [Domain] Federal Tax Authority Domestic Country [Member] State Tax Authority State And Local Jurisdiction [Member] Tax Credit Carryforward Tax Credit Carryforward [Axis] Tax Credit Carryforward, Name Tax Credit Carryforward Name [Domain] Research and Development Tax Credit Research [Member] Income Tax Disclosure [Line Items] Income Tax Disclosure [Line Items] Increase (decrease) in deferred tax valuation allowance Valuation Allowance Deferred Tax Asset Change In Amount Operating loss carry forwards expiration. Tax credit carry forward expiration. Net operating loss carryforwards Operating Loss Carryforwards Operating loss carryforward expiration year Operating Loss Carry Forwards Expiration Year Tax credit carryforwards Tax Credit Carryforward Amount Tax credit carryforward expiration year Tax Credit Carry Forward Expiration Year Balance at beginning of year Unrecognized Tax Benefits Additions based on tax positions related to prior year Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions Additions based on tax positions related to current year Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions Balance at end of year Unrecognized tax benefits that would affect the effective tax rate if recognized Unrecognized Tax Benefits That Would Impact Effective Tax Rate Accrued interest and penalties related to unrecognized tax benefits Unrecognized Tax Benefits Income Tax Penalties And Interest Accrued Weighted average number of shares outstanding basic and diluted. Numerator: Net Income Loss [Abstract] Denominator: Weighted Average Number Of Shares Outstanding Basic And Diluted [Abstract] Weighted average number of shares outstanding—basic and diluted Net loss per share—basic and diluted Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share [Table] Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share [Table] Antidilutive Securities Antidilutive Securities Excluded From Computation Of Earnings Per Share By Antidilutive Securities [Axis] Antidilutive Securities, Name Antidilutive Securities Name [Domain] Options to Purchase Common Stock Stock Option [Member] Warrants to Purchase Convertible Preferred Stock Warrant [Member] Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] Antidilutive securities excluded from computation of earnings per share, shares Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount Research and development service expenses Related Party Transaction Expenses From Transactions With Related Party Allowance for lease improvement. Loss Contingencies [Table] Loss Contingencies [Table] Lease Arrangement, Type Lease Arrangement Type [Axis] Lease Arrangement, Type Lease Arrangement Type [Domain] Facility Lease Agreement [Member] Amended Facility Lease Agreement Amended Facility Lease Agreement [Member] Category of Item Purchased Long Term Purchase Commitment By Category Of Item Purchased [Axis] Long-term Purchase Commitment, Category of Item Purchased Long Term Purchase Commitment Category Of Item Purchased [Domain] Research and Development Equipment Research And Development Arrangement [Member] Office Space Capital Additions [Member] Loss Contingency Nature Loss Contingencies By Nature Of Contingency [Axis] Loss Contingency, Nature Loss Contingency Nature [Domain] Information by guarantees and indemnifications contract. Guarantees and Indemnifications Guarantees And Indemnifications Agreement [Member] Loss Contingencies [Line Items] Loss Contingencies [Line Items] Lease expiration date Lease Expiration Date1 Lease improvement allowance maximum amount Allowance For Lease Improvement Amount provided lessor with irrevocable letter of credit Provision For Lease Losses 2015 Operating Leases Future Minimum Payments Due Current 2016 Operating Leases Future Minimum Payments Due In Two Years 2017 Operating Leases Future Minimum Payments Due In Three Years 2018 Operating Leases Future Minimum Payments Due In Four Years 2019 Operating Leases Future Minimum Payments Due In Five Years Total Operating Leases Future Minimum Payments Due Rent expense under operating leases Operating Leases Rent Expense Net Purchase commitments Long Term Purchase Commitment Amount Indemnification agreement period. Number of days for written terminate indemnification agreement Indemnification Agreement Termination Written Notification Period Liabilities recorded associated with indemnification agreement Total revenue Operating expenses Net income (loss) Net income (loss) per share: Earnings Per Share Basic And Diluted [Abstract] Basic Earnings Per Share Basic Diluted Earnings Per Share Diluted Basic and diluted net loss per common share