Entity Central Index Key Cover [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 Entity Current Reporting Status Entity Current Reporting Status Entity Interactive Data Current Entity Interactive Data Current Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Entity Small Business Entity Small Business Entity Emerging Growth Company Entity Emerging Growth Company Entity Ex Transition Period Entity Ex Transition Period Entity Common Stock, Shares Outstanding Entity Common Stock Shares Outstanding Entity Shell Company Entity Shell Company Title of 12(b) Security Security12b Title Security Exchange Name Security Exchange Name Entity File Number Entity File Number Entity Incorporation, State or Country Code Entity Incorporation State Country Code Entity Tax Identification Number Entity Tax Identification Number Entity Address, Address Line One Entity Address Address Line1 Entity Address, Address Line Two Entity Address Address Line2 Entity Address, Address Line Three Entity Address Address Line3 Entity Address, City or Town Entity Address City Or Town Entity Address, State or Province Entity Address State Or Province Entity Address, Postal Zip Code Entity Address Postal Zip Code City Area Code City Area Code Local Phone Number Local Phone Number Document Quarterly Report Document Quarterly Report Document Transition Report Document Transition Report Statement Of Financial Position [Abstract] ASSETS Assets [Abstract] Current assets: Assets Current [Abstract] Cash and cash equivalents Cash And Cash Equivalents At Carrying Value Restricted cash Restricted Cash And Cash Equivalents At Carrying Value Short-term investments Short Term Investments 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 Right-of-use asset, net Operating Lease Right Of Use Asset 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 expenses and other current liabilities Accrued Liabilities And Other Liabilities Current portion of deferred revenue Contract With Customer Liability Current Current portion of right-of-use liability Operating Lease Liability Current Total current liabilities Liabilities Current Long-term liabilities: Liabilities Noncurrent [Abstract] Deferred revenue, less current portion Contract With Customer Liability Noncurrent Right-of-use liability, less current portion Operating Lease Liability Noncurrent Loan payable Long Term Loans Payable Other long-term liabilities Other Liabilities Noncurrent Total long-term liabilities Liabilities Noncurrent Total liabilities Liabilities Commitments Commitments And Contingencies Stockholders’ equity: Stockholders Equity [Abstract] Preferred stock, $0.001 par value, 10,000,000 shares authorized; 0 shares outstanding at June 30, 2020 and December 31, 2019 Preferred Stock Value Common stock, $0.0001 par value, 100,000,000 shares authorized; 38,512,744 and 27,140,484 shares issued and outstanding at June 30, 2020 and December 31, 2019, respectively Common Stock Value Additional paid-in capital Additional Paid In Capital Common Stock Accumulated other comprehensive income Accumulated Other Comprehensive Income Loss Available For Sale Securities Adjustment 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: Revenues [Abstract] Total revenues Revenue From Contract With Customer Excluding Assessed Tax Type of revenue [extensible list] Type Of Revenue Extensible List 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 (expense) income: Nonoperating Income Expense [Abstract] Interest expense Interest Expense Interest income Investment Income Interest Other (expense) income Other Nonoperating Income Expense Total other (expense) income Nonoperating Income Expense Net loss Net Income Loss Other comprehensive loss: Other Comprehensive Income Loss Net Of Tax Period Increase Decrease [Abstract] Unrealized gain on marketable securities Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax Comprehensive loss Comprehensive Income Net Of Tax 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 Weighted-average number of common shares used to compute net loss per share attributable to common stockholders—basic and diluted Weighted Average Number Of Share Outstanding Basic And Diluted Depreciation and related adjustment. Non-cash operating lease expense. Statement Of Cash Flows [Abstract] Statement [Table] Statement [Table] Sale of Stock Subsidiary Sale Of Stock [Axis] Sale of Stock Sale Of Stock Name Of Transaction [Domain] At the market stock offering. At-the-Market Offering [Member] At The Market Stock Offering [Member] Private Placement [Member] Private Placement [Member] Statement [Line Items] Statement [Line Items] CASH FLOWS FROM OPERATING ACTIVITIES: Net Cash Provided By Used In Operating Activities [Abstract] Net loss Profit Loss Adjustments to reconcile net loss to net cash from operating activities: Adjustments To Reconcile Net Income Loss To Cash Provided By Used In Operating Activities [Abstract] Depreciation Depreciation And Related Adjustment Amortization and accretion of investments Accretion Amortization Of Discounts And Premiums Investments Non-cash operating lease expense Noncash Operating Lease Expense Non-cash interest expense Paid In Kind Interest Stock-based compensation Share Based Compensation Other Other Noncash Income Expense Changes in operating assets and liabilities: Increase Decrease In Operating Capital [Abstract] Prepaid expenses and other assets Increase Decrease In Prepaid Deferred Expense And Other Assets Accounts payable Increase Decrease In Accounts Payable Deferred revenue Increase Decrease In Contract With Customer Liability Accrued expenses 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 CASH FLOWS FROM INVESTING ACTIVITIES: Net Cash Provided By Used In Investing Activities [Abstract] Purchases of short-term investments Payments To Acquire Short Term Investments Proceeds from sales and maturities of short-term investments Proceeds From Sale And Maturity Of Available For Sale Securities Net cash used in investing activities Net Cash Provided By Used In Investing Activities CASH FLOWS FROM FINANCING ACTIVITIES: Net Cash Provided By Used In Financing Activities [Abstract] Proceeds from issuance of common stock, net Proceeds From Issuance Of Common Stock Proceeds from debt agreement, net Proceeds From Debt Net Of Issuance Costs Proceeds from Employee Stock Purchase Plan Proceeds From Stock Plans Proceeds from stock option exercises Proceeds From Stock Options Exercised Net cash provided by financing activities Net Cash Provided By Used In Financing Activities NET INCREASE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CASH, CASH EQUIVALENTS AND RESTRICTED CASH—beginning of period Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations CASH, CASH EQUIVALENTS AND RESTRICTED CASH —end of period SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION: Supplemental Cash Flow Information [Abstract] Cash paid for interest Interest Paid Net Organization Consolidation And Presentation Of Financial Statements [Abstract] Nature of Business Nature Of Operations Accounting Policies [Abstract] Basis of Presentation Business Description And Basis Of Presentation [Text Block] Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Revenue From Contract With Customer [Abstract] Revenue from Contracts with Customers Revenue From Contract With Customer [Text Block] Earnings Per Share [Abstract] Net Loss per Share Attributable to Common Stockholders Earnings Per Share [Text Block] Significant agreements disclosure. Equity [Abstract] Significant Agreements Significant Agreements Disclosure [Text Block] Fair Value Disclosures [Abstract] Fair Value Measurements Fair Value Measurement Inputs Disclosure [Text Block] Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract] Prepaid Expenses and Other Current Assets Other Current Assets [Text Block] Payables And Accruals [Abstract] Accrued Expenses and Other Current Liabilities Accounts Payable Accrued Liabilities And Other Liabilities Disclosure Current [Text Block] Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] Stock-Based Compensation Disclosure Of Compensation Related Costs Share Based Payments [Text Block] Postemployment Benefits [Abstract] Employee Stock Purchase Plan Compensation And Employee Benefit Plans Other Than Share Based Compensation [Text Block] Debt Disclosure [Abstract] Loan Payable Debt Disclosure [Text Block] Stockholders' Equity Stockholders Equity Note Disclosure [Text Block] Related Party Transactions [Abstract] Related-Party Transactions Related Party Transactions Disclosure [Text Block] Principles of Consolidation Consolidation Policy [Text Block] Significant accounting policies. Significant Accounting Policies Significant Accounting Policies Policy [Text Block] Disclosure of accounting policy for Significant risks and uncertainties. Significant Risks and Uncertainties Significant Risks And Uncertainties Policy [Text Block] Debt Issuance Cost Debt Policy [Text Block] Derivative Financial Instruments Derivatives Policy [Text Block] Use of Estimates Use Of Estimates Computation of Basic and Diluted Net Loss per Share Attributable to Common Stockholders Schedule Of Earnings Per Share Basic And Diluted Table [Text Block] Potential Dilutive Securities Excluded from Computation of Diluted Net Loss per Common Share Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share [Text Block] Schedule of Fair Values of Financial Assets and Liabilities Measured at Fair Value Schedule Of Fair Value Assets And Liabilities Measured On Recurring Basis Table [Text Block] Summary of Available-for-Sale Securities Debt Securities Available For Sale Table [Text Block] Schedule of Prepaid Expenses and Other Current Assets Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Text Block] Schedule of Accrued Expenses and Other Current Liabilities Schedule Of Accounts Payable And Accrued Liabilities Table [Text Block] Share Based Compensation Expense Related to Issuance of Stock Option Awards to Employees and Non Employees Related to Employee Stock Purchase Plan Schedule Of Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Text Block] Compensation Expense by Type of Award Disclosure Of Share Based Compensation Arrangements By Share Based Payment Award [Text Block] Summary of Maturities of Principal Obligations Under Long-term Debt Schedule Of Maturities Of Long Term Debt Table [Text Block] Summary of Changes in Stockholders' Equity Schedule Of Stockholders Equity Table [Text Block] Schedule of Common Stock Reserved for Future Issuance Schedule Of Stockholders Equity Note Warrants Or Rights [Text Block] Number of operating segments Number Of Operating Segments Date of incorporation Entity Incorporation Date Of Incorporation State of incorporation Period of termination after first commercial sale of first licensed product. Upfront payment allocated to equity purchase. Non refundable up front payment received. Upfront payments received. Potential milestone payments receivable. Accounting Changes And Error Corrections [Abstract] New Accounting Pronouncements Or Change In Accounting Principle [Table] New Accounting Pronouncements Or Change In Accounting Principle [Table] Collaborative Arrangement and Arrangement Other than Collaborative Type Of Arrangement [Axis] Collaborative Arrangement and Arrangement Other than Collaborative Arrangements And Nonarrangement Transactions [Member] License agreement. License Agreement [Member] License Agreement [Member] Counterparty Name Counterparty Name [Axis] Counterparty Name Repurchase Agreement Counterparty Name [Domain] Kyowa Kirin Co., Ltd. Kyowa Kirin Co., Ltd. [Member] Kyowa Kirin Co Ltd [Member] Statistical Measurement Range [Axis] Statistical Measurement Range [Member] Maximum [Member] Maximum [Member] Minimum [Member] Minimum [Member] New Accounting Pronouncements Or Change In Accounting Principle [Line Items] New Accounting Pronouncements Or Change In Accounting Principle [Line Items] License agreement upfront payment received Upfront Payments Received Up-front payment allocated to equity purchase Upfront Payment Allocated To Equity Purchase Up-front license fee received Non Refundable Up Front Payment Received Milestone payment receivable upon achievement of development and commercial milestone Potential Milestone Payments Receivable Period of termination after first commercial sale of first licensed product Period Of Termination After First Commercial Sale Of First Licensed Product Upfront payment allocated to license fee. Up-front payment allocated to preferred stock value Up-front payment allocated to license fee Upfront Payment Allocated To License Fee Revenue from contract with customer milestone method factors. Milestone payment agreement terms Revenue From Contract With Customer Milestone Method Factors Milestone payment received Contract With Customer Liability Revenue Recognized Upfront payment allocation to performance obligation Revenue Remaining Performance Obligation Performance obligation period Revenue Remaining Performance Obligation Expected Timing Of Satisfaction Year1 Deferred revenue Contract With Customer Liability Schedule Of Earnings Per Share Basic By Common Class [Table] Schedule Of Earnings Per Share Basic By Common Class [Table] Antidilutive Securities Antidilutive Securities Excluded From Computation Of Earnings Per Share By Antidilutive Securities [Axis] Antidilutive Securities, Name Antidilutive Securities Name [Domain] Warrant [Member] Warrant [Member] Earnings Per Share Basic [Line Items] Earnings Per Share Basic [Line Items] Numerator—basic and diluted: Net Income Loss [Abstract] Net loss Deemed dividend due to warrant reset Dividends Net loss attributable to common stockholders—basic and diluted Net loss per share attributable to common stockholders—basic and diluted Denominator—basic and diluted: Weighted Average Number Of Shares Outstanding [Abstract] Weighted-average number of common shares used to compute net loss per share attributable to common stockholders—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] Options to Purchase Common Stock [Member] Employee Stock Option [Member] Warrants to purchase common stock. Warrants to Purchase Common Stock [Member] Warrants To Purchase Common Stock [Member] Employee stock purchase plan. Employee Stock Purchase Plan [Member] Employee Stock Purchase Plan [Member] RSUs [Member] Restricted Stock Units R S U [Member] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] Anti-dilutive securities excluded from computation of diluted net loss per common share Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount Number of common stock converted to warrants. Number of common stock warrants issued. Class of warrant or right issued. Equity Components Statement Equity Components [Axis] Equity Component Equity Component [Domain] Pre funded warrants. Pre-Funded Warrants [Member] Pre Funded Warrants [Member] Series one and series two warrants. Series 1 and Series 2 Warrants [Member] Series One And Series Two Warrants [Member] Biotechnology Value Fund, L.P. Biotechnology Value Fund, L.P. [Member] Biotechnology Value Fund L P [Member] Common Stock [Member] Common Stock [Member] Series one warrants. Series 1 Warrants [Member] Series One Warrants [Member] Series two warrants. Series 2 Warrants [Member] Series Two Warrants [Member] Number of common stock converted to warrants Number Of Common Stock Converted To Warrants Number of common stock warrants issued Number Of Common Stock Warrants Issued Common stock, new shares issued Stock Issued During Period Shares New Issues Warrant exercise price per share Class Of Warrant Or Right Exercise Price Of Warrants Or Rights1 Warrant issued Class Of Warrant Or Right Issued Stock issued during period shares pre-funded warrant exchange. Stock issued during period shares exercise of warrants. Pre-funded warrants exchange Stock Issued During Period Shares Pre Funded Warrant Exchange Exercise Series 1 and Series 2 warrants Stock Issued During Period Shares Exercise Of Warrants Potential milestone payments upon achievement of milestone. Aggregate potential milestone payable. License agreements expiration period. Upfront payments. Commitments And Contingencies Disclosure [Abstract] Schedule Of Collaborative Arrangements And Noncollaborative Arrangement Transactions [Table] Schedule Of Collaborative Arrangements And Noncollaborative Arrangement Transactions [Table] AbbVie license agreement. AbbVie License Agreement [Member] Abb Vie License Agreement [Member] Vitae Pharmaceuticals, Inc. Vitae Pharmaceuticals Inc [Member] Vitae Pharmaceuticals Inc [Member] Income Statement Location Income Statement Location [Axis] Income Statement Location Income Statement Location [Domain] Accrued milestone expenses. Accrued Milestone Expenses [Member] Accrued Milestone Expenses [Member] UCB license agreement. UCB License Agreement [Member] Ucb License Agreement [Member] UCB Biopharma. UCB Biopharma [Member] U C B Biopharma [Member] Subsequent Event Type Subsequent Event Type [Axis] Subsequent Event Type Subsequent Event Type [Domain] Subsequent Event [Member] Subsequent Event [Member] Clinical trial. Clinical Trial [Member] Clinical Trial [Member] Eastern Cooperative Oncology Group. Eastern Cooperative Oncology Group [Member] Eastern Cooperative Oncology Group [Member] Bayer Pharma AG . Bayer Pharma AG [Member] Bayer Pharma Ag [Member] Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items] Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items] Upfront milestone payable Upfront Payments Potential milestone payments to be made Potential Milestone Payments Upon Achievement Of Milestone Aggregate potential milestone payable Aggregate Potential Milestone Payable License expiration year License Agreements Expiration Period Research and development expense Clinical milestone payment. Clinical milestone payment Clinical Milestone Payment Milestone payment due. Contractual obligations term. Increase decrease in contractual obligation. Estimated remaining contractual obligation. Milestone payment payable Milestone Payment Due Increase in contractual obligation Increase Decrease In Contractual Obligation Aggregate payment obligation Contractual Obligation Estimated remaining contractual obligation Estimated Remaining Contractual Obligation Period of contractual obligation Contractual Obligations Term Upfront license fees paid. Up-front license fee paid Upfront License Fees Paid Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Table] Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Table] Fair Value Hierarchy and NAV Fair Value By Fair Value Hierarchy Level [Axis] Fair Value Hierarchy and NAV Fair Value Measurements Fair Value Hierarchy [Domain] Quoted Prices (Unadjusted) in Active Markets Level 1 [Member] Fair Value Inputs Level1 [Member] Significant Other Observable Inputs Level 2 [Member] Fair Value Inputs Level2 [Member] Significant Unobservable Inputs Level 3 [Member] Fair Value Inputs Level3 [Member] Measurement Basis Fair Value By Measurement Basis [Axis] Fair Value Disclosure Item Amounts [Default] Portion At Fair Value Fair Value Disclosure [Member] Fair Value Measurement Fair Value Disclosure Item Amounts [Domain] Carrying Value [Member] Carrying Reported Amount Fair Value Disclosure [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] Cash and cash equivalents Cash And Cash Equivalents Fair Value Disclosure Total assets Assets Fair Value Disclosure Fair value measurements. Fair Value Measurements [Table] Fair Value Measurements [Table] Fair Value Measurements [Table] Cash and Cash Equivalents Cash And Cash Equivalents [Axis] Cash and Cash Equivalents Restricted Cash And Cash Equivalents Cash And Cash Equivalents [Member] Overnight investments money market funds and corporate bonds. Overnight Investments, Money Market Funds and Highly Rated Corporate Bonds Member] Overnight Investments Money Market Funds And Corporate Bonds [Member] Asset Class Fair Value By Asset Class [Axis] Asset Class Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation By Asset Class [Domain] Corporate bonds and commercial paper. Corporate Bonds and Commercial Paper [Member] Corporate Bonds And Commercial Paper [Member] Commercial paper, corporate bonds and asset backed securities. Commercial Paper, Corporate Bonds and Asset Backed Securities [Member] Commercial Paper Corporate Bonds And Asset Backed Securities [Member] Investment Type Investment Type [Axis] Investments Investment Type Categorization [Member] Short-term Investments [Member] Short Term Investments [Member] Fair Value Measurements [Line Items] Fair Value Measurements [Line Items] Cash and cash equivalents fair value Available for sale debt securities fair value Available For Sale Securities Debt Securities Realized gains or losses recognized on the sale or maturity of available-for-sale securities Debt Securities Available For Sale Realized Gain Loss Available For Sale Securities Fair Value Disclosure [Abstract] Available For Sale Securities Fair Value Disclosure [Abstract] Debt Securities Available For Sale [Table] Debt Securities Available For Sale [Table] Commercial Paper [Member] Commercial Paper Not Included With Cash And Cash Equivalents [Member] Corporate Bonds [Member] Corporate Debt Securities [Member] Asset Back Securities [Member] Asset Backed Securities [Member] Schedule Of Available For Sale Securities [Line Items] Schedule Of Available For Sale Securities [Line Items] Amortized Cost Available For Sale Debt Securities Amortized Cost Basis Unrealized Gains Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax Unrealized Losses Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax Fair Value Reimbursable costs. Short-term deposits Deposits Assets Current Prepaid clinical supplies Supplies Interest receivable on investments Interest Receivable Current Reimbursable costs Reimbursable Costs Prepaid insurance Prepaid Insurance Other Other Prepaid Expense Current Total prepaid expenses and other current assets Accrued clinical costs current. Accrued professional fees Accrued Professional Fees Current Accrued compensation and related costs Employee Related Liabilities Current Accrued clinical costs Accrued Clinical Costs Current Other Other Accrued Liabilities Current Total accrued expenses and other current liabilities Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table] Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table] Plan Name Plan Name [Axis] Plan Name Plan Name [Domain] Two thousand fifteen omnibus incentive plan. 2015 Plan [Member] Two Thousand Fifteen Omnibus Incentive Plan [Member] Two thousand and seven stock incentive plan. 2007 Plan [Member] Two Thousand And Seven Stock Incentive Plan [Member] Title of Individual Title Of Individual [Axis] Title of Individual Title Of Individual With Relationship To Entity [Domain] Employees. Employees [Member] Employees [Member] Two thousand seven and two thousand fifteen stock incentive plan. 2015 and 2007 [Member] Two Thousand Seven And Two Thousand Fifteen Stock Incentive Plan [Member] Award Type Award Type [Axis] Award Type Share Based Compensation Arrangements By Share Based Payment Award Award Type And Plan Name [Domain] Restricted Stock Units [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share Based Compensation Arrangement By Share Based Payment Award [Line Items] Shares available for issuance Common Stock Capital Shares Reserved For Future Issuance Research and Development [Member] Research And Development Expense [Member] General and Administrative [Member] General And Administrative Expense [Member] Share based compensation expense, total Allocated Share Based Compensation Expense Share based compensation arrangement by share based payment award stock option grant date fair value. Stock option granted to certain executives, consultants and employees Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Options grant date fair value amount Share Based Compensation Arrangement By Share Based Payment Award Stock Option Grant Date Fair Value Weighted average grant date fair value of options Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Weighted Average Grant Date Fair Value Employee service share based compensation recognized stock options not met. Recognized compensation expense related to stock option not met Employee Service Share Based Compensation Recognized Stock Options Not Met Employee service share based compensation recognized stock options. Employee service share based compensation recognized stock options cancelled. Stock compensation expense Employee Service Share Based Compensation Recognized Stock Options Stock option not met, options cancelled Employee Service Share Based Compensation Recognized Stock Options Cancelled Stock options exercised, shares Stock Issued During Period Shares Stock Options Exercised Unrecognized compensation expense related to stock option and RSUs Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Weighted average period to recognize compensation expense Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Period For Recognition1 Shares, vesting period Share Based Compensation Arrangement By Share Based Payment Award Award Vesting Period1 Fair value of shares at grant date Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross Weighted average grant date fair value per share Sharebased Compensation Arrangement By Sharebased Payment Award Options Nonvested Options Forfeited Weighted Average Grant Date Fair Value Compensation And Retirement Disclosure [Abstract] Employee benefit plans. Schedule Of Employee Benefit Plans [Table] Schedule Of Employee Benefit Plans [Table] Schedule Of Employee Benefit Plans [Table] Employee Benefit Plans [Line Items] Employee Benefit Plans [Line Items] Common stock available for issuance Share Based Compensation Arrangement By Share Based Payment Award Number Of Additional Shares Authorized Common stock available for issuance Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Available For Grant Number of shares issued under plan Stock Issued During Period Shares Employee Stock Purchase Plans Compensation expense Debt Instrument [Table] Debt Instrument [Table] Lender Name Line Of Credit Facility [Axis] Line of Credit Facility, Lender Line Of Credit Facility Lender [Domain] Hercules Capital, Inc. Hercules [Member] Hercules Capital Inc [Member] Credit Facility Credit Facility [Axis] Credit Facility Credit Facility [Domain] Loan and security agreement. Loan Agreement [Member] Loan And Security Agreement [Member] Debt Instrument Debt Instrument [Axis] Debt Instrument, Name Debt Instrument Name [Domain] Term loan. Term Loan [Member] Term Loan [Member] Additional term loan. Additional Term Loan [Member] Additional Term Loan [Member] Variable Rate Variable Rate [Axis] Variable Rate Variable Rate [Domain] Wall Street Journal Prime Rate [Member] Prime Rate [Member] Debt instrument tranche two Tranche 2 [Member] Debt Instrument Tranche Two [Member] Scenario Statement Scenario [Axis] Scenario Scenario Unspecified [Domain] Scenario Forecast [Member] Scenario Forecast [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Aggregate maximum borrowings Line Of Credit Facility Maximum Borrowing Capacity Term loan Debt Instrument Face Amount Interest rate description Line Of Credit Facility Interest Rate Description Interest rate Debt Instrument Interest Rate Stated Percentage Basis spread on variable rate Debt Instrument Basis Spread On Variable Rate1 Percentage of prepayment premium of principal amount outstanding in first year. Percentage of prepayment premium of principal amount outstanding in second year. Percentage of prepayment premium of principal amount outstanding thereafter. Payment of facility charges. Percentage of repayment on aggregate principal amount of term loan advances. Maturity date Debt Instrument Maturity Date Percentage of prepayment premium of principal amount outstanding in first year Percentage Of Prepayment Premium Of Principal Amount Outstanding In First Year Percentage of prepayment premium of principal amount outstanding in second year Percentage Of Prepayment Premium Of Principal Amount Outstanding In Second Year Percentage of prepayment premium of principal amount outstanding thereafter prior to maturity date Percentage Of Prepayment Premium Of Principal Amount Outstanding Thereafter Facility charge paid Payment Of Facility Charges Percentage of repayment on aggregate principal amount of term loan advances Percentage Of Repayment On Aggregate Principal Amount Of Term Loan Advances Line of credit facility minimum cash covenant. Additional default interest rate. Minimum cash covenant Line Of Credit Facility Minimum Cash Covenant Default interest rate Additional Default Interest Rate Interest expense related to the loan agreement Amortized loss reacquired debt noncurrent. Remainder of 2020 Long Term Debt Maturities Repayments Of Principal Remainder Of Fiscal Year 2021 Long Term Debt Maturities Repayments Of Principal In Year Two 2022 Long Term Debt Maturities Repayments Of Principal In Year Three 2023 Long Term Debt Maturities Repayments Of Principal In Year Four Total principal outstanding Debt Instrument Carrying Amount Amortized final fee Amortized Loss Reacquired Debt Noncurrent Unamortized debt issuance costs Unamortized Debt Issuance Expense Total Stock issued during period value direct offering. Stock issued during period value direct offering. Stock issued during period value pre-funded common stock warrants from direct offering. Adjustments to additional paid in capital deemed dividend from repricing warrants. Adjustments to additional paid in capital repricing warrants. Stock issued during period value pre-funded warrant exchange. Stock issued during period value exercise of warrants. Stock issued during period value at the market offering net. Offering expenses associated with direct offering. Stock issued during period value common stock warrant with direct offering. Schedule Of Stock By Class [Table] Schedule Of Stock By Class [Table] Additional Paid-In Capital [Member] Additional Paid In Capital [Member] Accumulated Other Comprehensive Income / (Loss) [Member] Accumulated Other Comprehensive Income [Member] Accumulated Deficit [Member] Retained Earnings [Member] Class of Warrant or Right Class Of Warrant Or Right [Axis] Class of Warrant or Right Class Of Warrant Or Right [Domain] Series 1 and 2. Series 1 and 2 [Member] Series One And Two [Member] Class of Stock [Line Items] Class Of Stock [Line Items] Beginning balance Beginning balance, Shares Shares Outstanding Stock purchase under ESPP, Shares Proceeds from 'at-the-market' offering, net, value Stock Issued During Period Value At The Market Offering Net Stock issued during period shares at the market offering net. Proceeds from "at-the-market" offering, net, shares Stock Issued During Period Shares At The Market Offering Net Stock-based compensation expense Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value Offering expenses associated with direct offering Offering Expenses Associated With Direct Offering Issuance of common stock in exchange for pre-funded warrants, shares Stock Issued During Period Value Pre Funded Warrant Exchange Issuance of common stock in exchange for pre-funded warrants, shares Exercise Series 1 and Series 2 warrants, value Stock Issued During Period Value Exercise Of Warrants Proceeds from direct offering, net, value Stock Issued During Period Value Direct Offering Proceeds from direct offering,net, Shares Stock Issued During Period Shares Direct Offering Proceeds from pre-funded common stock warrant from direct offering, net, value Stock Issued During Period Value Pre Funded Common Stock Warrants From Direct Offering Issuance of common stock warrant with direct offering, value Stock Issued During Period Value Common Stock Warrant With Direct Offering Deemed dividend from repricing Series 1 and 2 warrants Adjustments To Additional Paid In Capital Deemed Dividend From Repricing Warrants Repricing Series 1 and 2 warrants Adjustments To Additional Paid In Capital Repricing Warrants Proceeds from exercise of stock options, value Stock Issued During Period Value Stock Options Exercised Proceeds from exercise of stock options, shares Unrealized gains on short-term investments Employee withholdings ESPP Adjustment To Additional Paid In Capital Income Tax Effect From Share Based Compensation Net Ending balance Ending balance, Shares Stock issued during period value at the market offering expenses. Stock issued during period value direct offering common stock warrant. Stock issued during period value offering expenses. Stock issued during period value pre funded common stock warrant. Stock issued during period value pre-funded common stock warrant offering expenses. At-the-market, offering expenses Stock Issued During Period Value At The Market Offering Expenses Direct offering, common stock warrants Stock Issued During Period Value Direct Offering Common Stock Warrant Direct offering, offering expenses Stock Issued During Period Value Offering Expenses Pre-funded common stock warrants Stock Issued During Period Value Pre Funded Common Stock Warrant Pre-funded common stock warrants offering expenses Stock Issued During Period Value Pre Funded Common Stock Warrant Offering Expenses Payment specified percentage of gross proceeds from sale of shares. Legal Entity Legal Entity [Axis] Entity Entity [Domain] Cowen and Company LLC. Cowen and Company LLC [Member] Cowen And Company L L C [Member] Related Party Transaction Related Party Transaction [Axis] Related Party Transaction Related Party Transaction [Domain] At the market equity offering sales agreement. At The Market Equity Offering Sales Agreement [Member] At The Market Equity Offering Sales Agreement [Member] Series warrants. Series Warrants [Member] Series Warrants [Member] Measurement Input Type Measurement Input Type [Axis] Measurement Input Type Measurement Input Type [Domain] Weighted Average Volatility Rate [Member] Measurement Input Option Volatility [Member] Class Of Stock [Line Items] Proceeds from issuance of common stock in follow-on public stock offering, net Common stock, new shares issued Payment percentage of gross proceeds from sales agreement Payment Specified Percentage Of Gross Proceeds From Sale Of Shares Number of series of warrants. Class of warrant or right term. Offering price per share. Gross proceeds from offering. Offering cost. Number of series of warrants Number Of Series Of Warrants Warrants issued (in shares) Class Of Warrant Or Right Number Of Securities Called By Warrants Or Rights Warrant term Class Of Warrant Or Right Term Offering price Offering Price Per Share Gross proceeds from offering Gross Proceeds From Offering Offering costs Offering Cost Weighted average exercise price of warrants. Adjusted weighted average exercise price of warrants. Weighted average price Weighted Average Exercise Price Of Warrants Adjusted exercise price Adjusted Weighted Average Exercise Price Of Warrants Maximum period allowed to increase beneficial ownership limitation after notice. Exercise of warrants lower limit after exercise as percentage of common stock. Maximum beneficial ownership limitation percentage. Maximum period allowed to increase beneficial ownership limitation after notice Maximum Period Allowed To Increase Beneficial Ownership Limitation After Notice Minimum percentage of common stock can be held upon exercise of warrant Exercise Of Warrants Lower Limit After Exercise As Percentage Of Common Stock Maximum beneficial ownership limitation percentage Maximum Beneficial Ownership Limitation Percentage Fair value of warrants. Total fair value of warrant Fair Value Of Warrants Warrants and rights outstanding, measurement input Warrants And Rights Outstanding Measurement Input Weighted average expected term Warrants And Rights Outstanding Term Deemed dividend transferred to the warrant holders Series 1 and 2 warrants. Series 1 and 2 Warrants [Member] Series1 And2 Warrants [Member] Common stock reserved for future issuance