Entity Central Index Key Document And Entity Information Document And Entity Information [Abstract] Entity Registrant Name Entity Registrant Name Entity Central Index Key Amendment Flag Amendment Flag Current Fiscal Year End Date Current Fiscal Year End Date Document Type Document Type 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 Well-known Seasoned Issuer Entity Well Known Seasoned Issuer 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 Shell Company Entity Shell Company Entity Voluntary Filers Entity Voluntary Filers Entity Current Reporting Status Entity Current Reporting Status Entity Public Float Entity Public Float Entity Common Stock, Shares Outstanding Entity Common Stock Shares Outstanding Statement Of Financial Position [Abstract] Assets Assets [Abstract] Current assets: Assets Current [Abstract] Cash and cash equivalents Cash And Cash Equivalents At Carrying Value Prepaid research and development contracts Prepaid Expense Current Other current assets Other Assets Current Total current assets Assets Current Furniture and equipment, net Property Plant And Equipment Net Deposits Deposits Assets Noncurrent Total assets Assets Liabilities and stockholders’ equity Liabilities And Stockholders Equity [Abstract] Current liabilities: Liabilities Current [Abstract] Accounts payable and accrued expenses Accounts Payable And Accrued Liabilities Current Total current liabilities Liabilities Current Commitments and contingencies (Note 11) Commitments And Contingencies Stockholders’ equity: Stockholders Equity [Abstract] Common stock, $0.0001 par value per share; 300,000,000 shares authorized and 40,588,004 and 27,070,038 shares issued and outstanding at December 31, 2018 and 2017, respectively. Common Stock Value Additional paid-in capital Additional Paid In Capital Common Stock Accumulated deficit Retained Earnings Accumulated Deficit Total stockholders’ equity Stockholders Equity Total liabilities and stockholders’ equity Liabilities And Stockholders Equity 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 Grant income. Income Statement [Abstract] License revenue, and other 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 Grant income Grant Income Interest income (expense), net Interest Income Expense Nonoperating Net Total other income (expense) Nonoperating Income Expense Net and comprehensive loss Net Income Loss Reconciliation of net loss attributable to common stockholders: Net Income Loss Available To Common Stockholders Basic [Abstract] Net and comprehensive loss Adjustment of redeemable convertible preferred stock to redemption value Temporary Equity Accretion To Redemption Value Adjustment 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 in computing net loss per share attributable to common stockholders, basic and diluted Weighted Average Number Of Share Outstanding Basic And Diluted Stock issued during period shares conversion of convertible notes and accrued interest. Adjustments to additional paid in capital share exchange in connection with merger. Share exchange during period shares in connection with merger. Temporary equity shares conversion of convertible securities. Temporary equity value conversion of convertible securities. Statement Of Stockholders Equity [Abstract] Statement [Table] Statement [Table] Equity Components Statement Equity Components [Axis] Equity Component Equity Component [Domain] Redeemable Convertible Preferred Stock [Member] Preferred Stock [Member] Common Stock [Member] Common Stock [Member] Additional Paid-In Capital [Member] Additional Paid In Capital [Member] Accumulated Deficit [Member] Retained Earnings [Member] Statement [Line Items] Statement [Line Items] Redeemable convertible preferred stock, Balance Redeemable Noncontrolling Interest Equity Preferred Carrying Amount Redeemable convertible preferred stock, Balance, Shares Temporary Equity Shares Outstanding Balance Balance, Shares Shares Outstanding Redeemable convertible preferred stock, Adjustment of redeemable convertible preferred stock to redemption value Temporary Equity Accretion To Redemption Value Adjustment of redeemable convertible preferred stock to redemption value Redeemable convertible preferred stock, Conversion of preferred stock Temporary Equity Value Conversion Of Convertible Securities Redeemable convertible preferred stock, Conversion of preferred stock, Shares Temporary Equity Shares Conversion Of Convertible Securities Conversion of redeemable convertible preferred stock Stock Issued During Period Value Conversion Of Convertible Securities Conversion of redeemable convertible preferred stock, Shares Stock Issued During Period Shares Conversion Of Convertible Securities Conversion of convertible notes and accrued interest Adjustments To Additional Paid In Capital Convertible Debt With Conversion Feature Conversion of convertible notes and accrued interest, Shares Stock Issued During Period Shares Conversion Of Convertible Notes And Accrued Interest Share exchange in connection with Merger Adjustments To Additional Paid In Capital Share Exchange In Connection With Merger Share exchange in connection with Merger, Shares Share Exchange During Period Shares In Connection With Merger Issuance of restricted stock Stock Issued During Period Value Restricted Stock Award Gross Issuance of restricted stock, Shares Stock Issued During Period Shares Restricted Stock Award Gross Issuance of common stock,net of issuance costs Stock Issued During Period Value New Issues Issuance of common stock, net of issuance costs, Shares Stock Issued During Period Shares New Issues Issuance of common stock upon exercise of stock options Stock Issued During Period Value Stock Options Exercised Issuance of common stock upon exercise of stock options, Shares Stock Issued During Period Shares Stock Options Exercised Forfeiture of restricted stock Stock Issued During Period Value Restricted Stock Award Forfeitures Forfeiture of restricted stock, Shares Stock Issued During Period Shares Restricted Stock Award Forfeited Share-based compensation expense Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value Net and comprehensive loss Balance Balance, Shares Payments of stock issuance cost Payments Of Stock Issuance Costs Increase decrease in prepaid research and development contracts. Noncash Financing Items. Statement Of Cash Flows [Abstract] Operating activities: Net Cash Provided By Used In Operating Activities [Abstract] Adjustments to reconcile net and comprehensive loss to net cash used in operating activities: Adjustments To Reconcile Net Income Loss To Cash Provided By Used In Operating Activities [Abstract] Depreciation Depreciation Stock-based compensation Share Based Compensation Amortization of debt issuance costs Amortization Of Financing Costs Interest expense related to convertible note conversion Paid In Kind Interest Changes in operating assets and liabilities: Increase Decrease In Operating Capital [Abstract] Prepaid research and development contracts Increase Decrease In Prepaid Research And Development Contracts Other current assets Increase Decrease In Other Current Assets Deposits Increase Decrease In Deposits Accounts payable and accrued expenses Increase Decrease In Accounts Payable And Accrued Liabilities Net cash used in operating activities Net Cash Provided By Used In Operating Activities Investing activities: Net Cash Provided By Used In Investing Activities [Abstract] Purchase of furniture and equipment Payments To Acquire Property Plant And Equipment Proceeds from maturities of short-term investments Proceeds From Maturities Prepayments And Calls Of Shortterm Investments Net cash (used in) provided by investing activities Net Cash Provided By Used In Investing Activities Financing activities: Net Cash Provided By Used In Financing Activities [Abstract] Proceeds from exercise of stock options Proceeds From Stock Options Exercised Proceeds from issuances of convertible notes Proceeds From Convertible Debt Proceeds from sale of common stock Proceeds From Issuance Of Common Stock Cash paid in connection with the sale of common stock Net cash provided by financing activities Net Cash Provided By Used In Financing Activities 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 Non-cash financing activities Noncash Financing Items [Abstract] Conversion of redeemable convertible preferred stock into common stock Conversion Of Stock Amount Converted1 Conversion of convertible notes and accrued interest into common stock Debt Conversion Converted Instrument Amount1 Accretion of redeemable convertible preferred stock to redemption value Organization Consolidation And Presentation Of Financial Statements [Abstract] Nature of Organization and Operations Organization Consolidation And Presentation Of Financial Statements Disclosure [Text Block] Accounting Policies [Abstract] Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Payables And Accruals [Abstract] Accounts Payable and Accrued Expenses Accounts Payable And Accrued Liabilities Disclosure [Text Block] Property Plant And Equipment [Abstract] Furniture and Equipment Property Plant And Equipment Disclosure [Text Block] The entire disclosure for terms, amounts, nature of changes, rights and privileges, dividends, and other matters related to common stock. Equity [Abstract] Common Stock Common Stock [Text Block] Preferred Stock Preferred Stock [Text Block] Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] Stock-Based Compensation 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 Attributable to Common Stockholders Earnings Per Share [Text Block] Quarterly Financial Data [Abstract] Quarterly Results Quarterly Financial Information [Text Block] Commitments And Contingencies Disclosure [Abstract] Commitments and Contingencies Commitments Disclosure [Text Block] Compensation And Retirement Disclosure [Abstract] Employee Retirement Plan Pension And Other Postretirement Benefits Disclosure [Text Block] Compensation Related Costs [Abstract] Employee Bonus Plan Compensation Related Costs General [Text Block] Disclosure of employee stock purchase plan. Employee Stock Purchase Plan Disclosure Of Employee Stock Purchase Plan [Text Block] License agreement. Revenue From Contract With Customer [Abstract] License Agreement License Agreement [Text Block] Basis of Presentation Basis Of Accounting Policy Policy [Text Block] Segment Information Segment Reporting Policy Policy [Text Block] Use of Estimates Use Of Estimates Cash and Cash Equivalents Cash And Cash Equivalents Policy [Text Block] Revenue Recognition Revenue From Contract With Customer Policy [Text Block] Grant income. Grant Income Grant Income Policy [Text Block] Research and Development Research And Development Expense Policy Patents Intangible Assets Finite Lived Policy Costs Incurred To Renew Or Extend Income Taxes Income Tax Policy [Text Block] Net Loss per Share Attributable to Common Stockholders Earnings Per Share Policy [Text Block] Stock-Based Compensation Share Based Compensation Option And Incentive Plans Policy Fair Value of Financial Instruments Fair Value Of Financial Instruments Policy Concentrations of Credit Risk and Off-Balance Sheet Risk Concentration Risk Credit Risk Comprehensive Loss Comprehensive Income Policy Policy [Text Block] Furniture and Equipment Property Plant And Equipment Policy [Text Block] Recent Accounting Pronouncements New Accounting Pronouncements Policy Policy [Text Block] Schedule of Assets Measured on Recurring Basis Fair Value Assets Measured On Recurring Basis [Text Block] Schedule of Accounts Payable and Accrued Expenses Schedule Of Accounts Payable And Accrued Liabilities Table [Text Block] Schedule of Furniture and Equipment Property Plant And Equipment [Text Block] Summary of Stock Option Activity Schedule Of Share Based Compensation Stock Options Activity Table [Text Block] Stock Options Valuation Assumptions Schedule Of Share Based Payment Award Stock Options Valuation Assumptions Table [Text Block] Summary of Restricted Stock Activity Schedule Of Sharebased Compensation Restricted Stock And Restricted Stock Units Activity Table [Text Block] Summary of Recognized Compensation Cost Related to Employee and Non-employee Stock-Based Compensation Activity Schedule Of Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Text Block] Schedule of Reconciliation of Statutory Federal Income Tax Schedule Of Effective Income Tax Rate Reconciliation Table [Text Block] Schedule of Significant Components of Deferred Tax Assets and Liabilities Schedule Of Deferred Tax Assets And Liabilities Table [Text Block] Schedule of Computation of Basic and Diluted Net Loss per Share Schedule Of Earnings Per Share Basic And Diluted Table [Text Block] Schedule of Weighted Average Common Stock Equivalents Excluded from Calculation of Diluted Net Loss per Share Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share [Text Block] Quarterly Financial Information Disclosure [Abstract] Summary of Quarterly Results Schedule Of Quarterly Financial Information Table [Text Block] Schedule of Non-cancellable Future Minimum Lease Payments Related to Operating Leases Schedule Of Future Minimum Rental Payments For Operating Leases Table [Text Block] Schedule Of Stock By Class [Table] Schedule Of Stock By Class [Table] Legal Entity Legal Entity [Axis] Entity Entity [Domain] Zeta Acquisition Corp. II. Zeta Acquisition Corp. II [Member] Zeta Acquisition Corp I I [Member] Sale of Stock Subsidiary Sale Of Stock [Axis] Sale of Stock Sale Of Stock Name Of Transaction [Domain] Private Placement [Member] Private Placement [Member] Range Range [Axis] Range Range [Member] Minimum [Member] Minimum [Member] Maximum [Member] Maximum [Member] Public offering 2018 Public Offering [Member] Public Offering [Member] Underwriters’ Exercise of Option [Member] Over Allotment Option [Member] Class Of Stock [Line Items] Class Of Stock [Line Items] Preferred stock, shares authorized Preferred Stock Shares Authorized Preferred stock, par value Preferred Stock Par Or Stated Value Per Share Capital stock conversion basis ratio. Capital stock conversion basis ratio Capital Stock Conversion Basis Ratio Warrants issuance term. Number of shares surrendered for cancellation Stock Repurchased And Retired During Period Shares Common stock sold in offering Common stock issued to private placement, price per share Shares Issued Price Per Share Net proceeds from issuance of common stock in private placement Proceeds From Issuance Of Private Placement Issuance of warrants term Warrants Issuance Term Number of warrants issued to purchase common stock Class Of Warrant Or Right Number Of Securities Called By Each Warrant Or Right Warrants issued to purchase common stock, exercise price Class Of Warrant Or Right Exercise Price Of Warrants Or Rights1 Percentage of Interest owned in the combined enterprise Business Acquisition Percentage Of Voting Interests Acquired Underwriting discounts and commissions and offering expenses paid Summary of significant accounting policies. Summary of significant accounting policies. Summary Of Significant Accounting Policies [Table] Summary Of Significant Accounting Policies [Table] Adjustments for New Accounting Pronouncements Adjustments For New Accounting Pronouncements [Axis] Type of Adoption Type Of Adoption [Member] ASU 2016-02 [Member] Accounting Standards Update201602 [Member] Subsequent Event Type Subsequent Event Type [Axis] Subsequent Event Type Subsequent Event Type [Domain] Subsequent Event [Member] Subsequent Event [Member] Summary Of Significant Accounting Policies [Line Items] Summary Of Significant Accounting Policies [Line Items] Number of operating segment Number Of Operating Segments Uncertain tax positions Liability For Uncertain Tax Positions Current Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Table] Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Table] Measurement Frequency Fair Value By Measurement Frequency [Axis] Fair Value, Measurement Frequency Fair Value Measurement Frequency [Domain] Fair Value, Measurements, Recurring [Member] Fair Value Measurements Recurring [Member] 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] Level 1 [Member] Fair Value Inputs Level1 [Member] Level 2 [Member] Fair Value Inputs Level2 [Member] Level 3 [Member] Fair Value Inputs Level3 [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] Cash and cash equivalents Cash And Cash Equivalents Fair Value Disclosure Total assets Assets Fair Value Disclosure Furniture and equipment estimated useful lives Property Plant And Equipment Useful Life Right-of-use asset Operating Lease Right Of Use Asset Lease liabilities Operating Lease Liability Accrued project costs current. Accounts payable Accounts Payable Current Professional fees Accrued Professional Fees Current Accrued bonus Accrued Bonuses Current Accrued vacation Accrued Vacation Current Accrued project costs Accrued Project Costs Current Other Other Accrued Liabilities Current Total accounts payable and accrued expenses 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] Furniture [Member] Furniture And Fixtures [Member] Computers [Member] Computer Equipment [Member] Equipment [Member] Equipment [Member] Leasehold Improvements [Member] Leasehold Improvements [Member] Property, Plant and Equipment [Line Items] Property Plant And Equipment [Line Items] Furniture and equipment Property Plant And Equipment Gross Accumulated depreciation Accumulated Depreciation Depletion And Amortization Property Plant And Equipment Furniture and equipment, net Dividends common stock declared or paid Dividends Common Stock Cash Class of warrant or right term. Class of warrant or right expiration date. Warrants outstanding Class Of Warrant Or Right Outstanding Warrants exercise price per share Warrants term Class Of Warrant Or Right Term Warrants expiration date Class Of Warrant Or Right Expiration Date Temporary Equity Disclosure [Abstract] Preferred stock, shares issued Preferred Stock Shares Issued Preferred stock, shares outstanding Preferred Stock Shares Outstanding Share based compensation arrangement by share based payment award number of additional shares authorized annual percentage. 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] 2017 stock option and incentive plan. 2017 Stock Option and Incentive Plan [Member] Two Thousand Seventeen Stock Option And Incentive Plan [Member] Award Type Award Type [Axis] Equity Award Share Based Compensation Arrangements By Share Based Payment Award Award Type And Plan Name [Domain] Stock Option [Member] Employee Stock Option [Member] Title of Individual Title Of Individual [Axis] Relationship to Entity Title Of Individual With Relationship To Entity [Domain] Chief executive officer and chief financial officer. CEO and CFO [Member] Chief Executive Officer And Chief Financial Officer [Member] Vesting Vesting [Axis] Vesting Vesting [Domain] One-year Anniversary [Member] Share Based Compensation Award Tranche One [Member] Restricted Stock [Member] Restricted Stock [Member] Share Based Compensation Arrangement By Share Based Payment Award [Line Items] Share Based Compensation Arrangement By Share Based Payment Award [Line Items] Common stock shares available for issuance Common Stock Capital Shares Reserved For Future Issuance Percentage applied to the outstanding shares as annual increase in number of shares authorized for issuance Share Based Compensation Arrangement By Share Based Payment Award Number Of Additional Shares Authorized Annual Percentage Number of option awards granted. Vesting period Share Based Compensation Arrangement By Share Based Payment Award Award Vesting Period1 Vesting percentage Sharebased Compensation Arrangement By Sharebased Payment Award Award Vesting Rights Percentage Term of options to be granted Sharebased Compensation Arrangement By Sharebased Payment Award Expiration Period Number of awards granted Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross Number of option awards granted Number Of Option Awards Granted Shares, Outstanding at beginning balance Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number Shares, Granted Shares, Exercised Shares, Expired/cancelled Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures And Expirations In Period Shares, Outstanding at ending balance Shares, Expected to vest Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Outstanding Number Shares, Options exercisable Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number Weighted Average Exercise Price, Outstanding at beginning balance Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price Weighted Average Exercise Price, Granted Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price Weighted Average Exercise Price, Exercised Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price Weighted Average Exercise Price, Expired/cancelled Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures And Expirations In Period Weighted Average Exercise Price Weighted Average Exercise Price, Outstanding at ending balance Weighted Average Exercise Price, Expected to vest Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Outstanding Weighted Average Exercise Price Weighted Average Exercise Price, Options exercisable Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price Weighted Average Remaining Contractual Term, Outstanding Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 Weighted Average Remaining Contractual Term, Expected to vest Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested And Expected To Vest Outstanding Weighted Average Remaining Contractual Term1 Weighted Average Remaining Contractual Term, Options exercisable Sharebased Compensation Shares Authorized Under Stock Option Plans Exercise Price Range Exercisable Options Weighted Average Remaining Contractual Term2 Aggregate Intrinsic Value, Outstanding 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 Vested And Expected To Vest Outstanding Aggregate Intrinsic Value Aggregate Intrinsic Value, Options exercisable Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Intrinsic Value1 Aggregate intrinsic value of option outstanding Stock options exercised, intrinsic value Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value Compensation expense Allocated Share Based Compensation Expense Unrecognized compensation cost related to stock options Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Stock Options Weighted average period expected to be recognized Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Period For Recognition1 Weighted-average fair value of options granted Sharebased Compensation Arrangement By Sharebased Payment Award Options Nonvested Weighted Average Grant Date Fair Value Expected term (years) Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Expected Term1 Risk-free interest rate Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Risk Free Interest Rate Expected volatility Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate Expected dividend yield Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate Shares, Nonvested beginning balance Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Number Shares, Granted Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Grants In Period Shares, Vested Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Vested In Period Shares, Forfeited Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Forfeited In Period Shares, Nonvested ending balance Weighted Average Grant Date Fair Value, Nonvested beginning balance Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Weighted Average Grant Date Fair Value Weighted Average Grant Date Fair Value, Granted Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Grants In Period Weighted Average Grant Date Fair Value Weighted Average Grant Date Fair Value, Vested Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Vested In Period Weighted Average Grant Date Fair Value Weighted Average Grant Date Fair Value, Forfeited Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Forfeitures Weighted Average Grant Date Fair Value Weighted Average Grant Date Fair Value, Nonvested ending balance Disclosure Of Share Based Compensation Arrangements By Share Based Payment Award [Abstract] Disclosure Of Share Based Compensation Arrangements By Share Based Payment Award [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] Income Statement Location Income Statement Location [Axis] Income Statement Location Income Statement Location [Domain] Research and development [Member] Research And Development Expense [Member] General and administrative [Member] General And Administrative Expense [Member] Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] Stock-based compensation expense Income tax disclosure line items. Income tax disclosure. Income Tax Disclosure [Table] Income Tax Disclosure [Table] Tax Credit Carryforward Tax Credit Carryforward [Axis] Tax Credit Carryforward, Name Tax Credit Carryforward Name [Domain] Research and Development [Member] Research [Member] Income Tax Authority Income Tax Authority [Axis] Income Tax Authority Income Tax Authority [Domain] Federal [Member] Domestic Country [Member] State [Member] State And Local Jurisdiction [Member] Income Tax Disclosure [Line Items] Income Tax Disclosure [Line Items] Federal tax at statutory rate Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate Current income tax expense or benefit Current Income Tax Expense Benefit Deferred income tax expense or benefit Deferred Income Tax Expense Benefit Federal tax at statutory rate State and local tax at statutory rates, net of federal income tax Effective Income Tax Rate Reconciliation State And Local Income Taxes Research and development credits Effective Income Tax Rate Reconciliation Tax Credits Research Other Effective Income Tax Rate Reconciliation Other Reconciling Items Percent Change in valuation allowance Effective Income Tax Rate Reconciliation Change In Deferred Tax Assets Valuation Allowance Remeasurement of U.S. net deferred tax assets from 35% to 21% Effective Income Tax Rate Reconciliation Change In Enacted Tax Rate Effective tax rate Effective Income Tax Rate Continuing Operations Deferred tax assets and liabilities net before valuation allowance. Deferred tax assets: Components Of Deferred Tax Assets [Abstract] Net operating loss carryforwards Deferred Tax Assets Operating Loss Carryforwards Accrued expenses Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Stock-based compensation Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Research and development credits Deferred Tax Assets Tax Credit Carryforwards Research Other Deferred Tax Assets Other Total deferred tax assets Deferred Tax Assets Gross Deferred tax liabilities: Deferred Tax Liabilities [Abstract] Furniture and equipment Deferred Tax Liabilities Property Plant And Equipment Total deferred tax liabilities Deferred Income Tax Liabilities Net deferred tax assets before valuation allowance Deferred Tax Assets And Liabilities Net Before Valuation Allowance Less valuation allowance Deferred Tax Assets Valuation Allowance Net deferred tax asset Deferred Tax Assets Liabilities Net Increase (decrease) in valuation allowance Valuation Allowance Deferred Tax Asset Change In Amount Tax cuts and jobs act of 2017 net operating loss carryforwards. Operating loss carryforwards Operating Loss Carryforwards Operating loss carryforwards, expiration date Operating Loss Carryforwards Expiration Date Tax credit carryforwards Tax Credit Carryforward Amount Tax credit carryforwards, expiration date Tax Credit Carryforward Expiration Date 2017 Tax Act, net operating loss carryforwards Tax Cuts And Jobs Act Of2017 Net Operating Loss Carryforwards Accrued uncertain tax positions Unrecognized Tax Benefits Accrued interest and penalties on uncertain tax positions Unrecognized Tax Benefits Income Tax Penalties And Interest Accrued Weighted average common shares used in computing 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] 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 [Member] Warrants to Purchase Common Stock [Member] Warrant [Member] Weighted Average [Member] Weighted Average [Member] Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] Total amount of anti-dilutive securities excluded from computation of earnings per share Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount Weighted average number of share outstanding basic and diluted abstract Total operating expenses Other (expense) income, net Weighted average number of common shares used in computing net (loss) income per share: Weighted Average Number Of Share Outstanding Basic And Diluted [Abstract] Basic Weighted Average Number Of Shares Outstanding Basic Diluted Weighted Average Number Of Diluted Shares Outstanding Extinguishment of preferred stock Reclassifications Of Temporary To Permanent Equity Restricted Stock [Member] Dilutive impact of options to purchase common shares Incremental Common Shares Attributable To Call Options And Warrants Number of anti-dilutive securities excluded from computation of earnings per share Area of lease property. Schedule Of Operating Leased Assets [Table] Schedule Of Operating Leased Assets [Table] Balance Sheet Location Balance Sheet Location [Axis] Balance Sheet Location Balance Sheet Location [Domain] Accrued Expenses [Member] Accounts Payable And Accrued Liabilities [Member] Geographical Statement Geographical [Axis] Geographical Segment Geographical [Domain] Cincinnati, Ohio [Member] OHIO Lexington, Massachusetts [Member] MASSACHUSETTS Dexter, Michigan [Member] MICHIGAN Operating Leased Assets [Line Items] Operating Leased Assets [Line Items] Number of property leases Property Subject To Or Available For Operating Lease Number Of Units Area of lease property Area Of Lease Property Lease expiration date Lease Expiration Date1 Lease term Lessee Operating Lease Term Of Contract Total operating leases rent expense Operating Leases Rent Expense Net Total deferred rent included in accrued expenses Deferred Rent Credit Current Operating leases future minimum payments due in three years and thereafter. Operating leases, 2019 Operating Leases Future Minimum Payments Due Current Operating leases, 2020 Operating Leases Future Minimum Payments Due In Two Years Operating leases, 2021 and thereafter Operating Leases Future Minimum Payments Due In Three Years And Thereafter Contributions made under Plan Defined Contribution Plan Employer Discretionary Contribution Amount Defined contribution plan, sponsor location [extensible list] Defined Contribution Plan Sponsor Location Extensible List Defined contribution plan, tax status [extensible list] Defined Contribution Plan Tax Status Extensible List Deferred Compensation Arrangements [Abstract] Number of shares reserved for issuance annual increased percentage. Employee Stock Purchase Plan [Member] Employee Stock [Member] Maximum number of shares provided for issuance Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Authorized Percentage of annual increase in number of shares reserved for issuance Number Of Shares Reserved For Issuance Annual Increased Percentage Number of shares outstanding License Agreement. License agreement. License Agreement [Table] License Agreement [Table] Product and Service Product Or Service [Axis] Product and Service Products And Services [Domain] License [Member] License [Member] License Agreement [Line Items] License Agreement [Line Items] Cash received from license agreement Proceeds From License Fees Received License revenue