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 Current Fiscal Year End Date Current Fiscal Year End Date Entity Well-known Seasoned Issuer Entity Well Known Seasoned Issuer Entity Voluntary Filers Entity Voluntary Filers Entity Current Reporting Status Entity Current Reporting Status 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 ICFR Auditor Attestation Flag Icfr Auditor Attestation Flag Entity Common Stock, Shares Outstanding Entity Common Stock Shares Outstanding Entity Public Float Entity Public Float Document Annual Report Document Annual Report Document Transition Report Document Transition Report 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, Postal Zip Code Entity Address Postal Zip Code City Area Code City Area Code Local Phone Number Local Phone Number Entity Address, Address Line One Entity Address Address Line1 Entity Address, Address Line Two Entity Address Address Line2 Entity Address, City or Town Entity Address City Or Town Entity Address, State or Province Entity Address State Or Province Security Exchange Name Security Exchange Name Title of 12(b) Security Security12b Title Entity Interactive Data Current Entity Interactive Data Current Documents Incorporated by Reference Documents Incorporated By Reference [Text Block] Statement Of Financial Position [Abstract] Assets Assets [Abstract] Current assets: Assets Current [Abstract] Cash and cash equivalents Cash And Cash Equivalents At Carrying Value Available-for-sale investments Available For Sale Securities Debt Securities Current Other receivables Other Receivables Net Current Prepaid expenses Prepaid Expense Current Total current assets Assets Current Property and equipment, net Property Plant And Equipment Net Right-of-use assets 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 Accrued Liabilities Current Contract liability Contract With Customer Liability Current Current portion of operating lease liability Operating Lease Liability Current Term loans, net of issuance costs and discount (Note 6) Long Term Debt Current Total current liabilities Liabilities Current Long-term operating lease liability, net of current portion Operating Lease Liability Noncurrent Commitments and contingencies (Note 6) Commitments And Contingencies Stockholders’ equity: Stockholders Equity [Abstract] Preferred stock, $0.001 par value per share; 5,000,000 undesignated authorized shares; Class X Convertible Preferred Stock issued and outstanding shares – 0 and 1,643,961 as of December 31, 2020 and December 31, 2019, respectively Preferred Stock Value Common stock, $0.001 par value per share; 21,425,000 and 10,714,286 authorized shares as of December 31, 2020 and December 31, 2019, respectively; issued and outstanding shares – 11,018,954 and 3,891,787 as of December 31, 2020 and December 31, 2019, respectively Common Stock Value Additional paid-in capital Additional Paid In Capital Accumulated other comprehensive loss Accumulated Other Comprehensive Income Loss Net Of Tax Accumulated deficit Retained Earnings Accumulated Deficit Total aTyr Pharma stockholders’ equity Stockholders Equity Noncontrolling interest in Pangu BioPharma Limited Minority Interest Total stockholders' equity Stockholders Equity Including Portion Attributable To Noncontrolling Interest Total liabilities and stockholders’ equity Liabilities And Stockholders Equity Statement [Table] Statement [Table] Class of Stock Statement Class Of Stock [Axis] Class of Stock Class Of Stock [Domain] Class X convertible preferred stock. Class X Convertible Preferred Stock [Member] Class X Convertible Preferred Stock [Member] Statement [Line Items] Statement [Line Items] 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] Product and Service Product Or Service [Axis] Product and Service Products And Services [Domain] License revenue. License Revenues [Member] License Revenue [Member] Revenues: Revenue From Contract With Customer [Abstract] Total revenues Revenue From Contract With Customer Excluding Assessed Tax 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 Total other expense, net Nonoperating Income Expense Consolidated net loss Profit Loss Net loss attributable to noncontrolling interest in Pangu BioPharma Limited Net Income Loss Attributable To Noncontrolling Interest Net loss attributable to aTyr Pharma, Inc. Net Income Loss Net loss per share, basic and diluted Earnings Per Share Basic And Diluted Shares used in computing net loss per share, basic and diluted Weighted Average Number Of Share Outstanding Basic And Diluted Statement Of Income And Comprehensive Income [Abstract] Consolidated net loss Other comprehensive gain (loss): Other Comprehensive Income Loss Net Of Tax Period Increase Decrease [Abstract] Change in unrealized gain (loss) on available-for-sale investments, net of tax Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax Comprehensive loss Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest Comprehensive loss attributable to noncontrolling interest Pangu BioPharma Limited Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest Comprehensive loss attributable to aTyr Pharma, Inc. common stockholders Comprehensive Income Net Of Tax Stock issued during period, value, stock options exercised and release of restricted stock units. Stock issued during period, shares, stock options exercised and release of restricted stock units. Stock issued during period value at the market offerings net of offering costs. Stock issued during period shares at the market offerings net of offering costs. Stock issued during period shares conversion of Preferred Stock to Common Stock. Stock issued during period value conversion of Preferred Stock to Common Stock. Issuance of common stock upon exercise of options and release of restricted stock units share. Stock issued during period value at registered direct offering net of offering costs. Stock issued during period shares at registered direct offering net of offering costs. Statement Of Stockholders Equity [Abstract] Other Comprehensive Gain/(Loss) [Member] Statement Equity Components [Axis] Equity Component Equity Component [Domain] Common Stock [Member] Common Stock [Member] Additional Paid-In Capital [Member] Additional Paid In Capital [Member] Other Comprehensive Gain/(Loss) [Member] Accumulated Other Comprehensive Income [Member] Accumulated Deficit [Member] Retained Earnings [Member] Noncontrolling Interest [Member] Noncontrolling Interest [Member] Convertible Preferred Stock Convertible Preferred Stock [Member] Beginning balance Beginning balance, Shares Shares Outstanding Beginning balance Conversion of preferred stock to common stock Stock Issued During Period Value Conversion Of Preferred Stock To Common Stock Conversion of preferred stock to common stock, shares Stock Issued During Period Shares Conversion Of Preferred Stock To Common Stock Issuance of common stock from underwritten follow-on offering, net of offering costs Issuance Of Common Stock From Underwritten Follow On Offering Net Of Offering Costs Issuance of common stock from underwritten follow-on offering, net of offering costs, Shares Issuance Of Common Stock From Underwritten Follow On Offering Net Of Offering Costs Shares Issuance of common stock upon release of restricted stock units, Shares Issuance Of Common Stock Upon Exercise Of Options And Release Of Restricted Stock Units Share Exercise of common stock options and release of restricted stock units Stock Issued During Period Value Stock Options Exercised And Release Of Restricted Stock Units Issuance of common stock upon release of restricted stock units, Shares Stock Issued During Period Shares Stock Options Exercised And Release Of Restricted Stock Units Issuance of common stock pursuant to employee stock purchase plan Stock Issued During Period Value Employee Stock Purchase Plan Issuance of common stock pursuant to employee stock purchase plan, Shares Stock Issued During Period Shares Employee Stock Purchase Plans Issuance of common stock from at the market offerings, net of offering costs Stock Issued During Period Value At The Market Offerings Net Of Offering Costs Issuance of common stock from at the market offerings, net of offering costs, Shares Stock Issued During Period Shares At The Market Offerings Net Of Offering Costs Issuance of common stock from registered direct offering, net of offering costs Stock Issued During Period Value At Registered Direct Offering Net Of Offering Costs Issuance of common stock from registered direct offering, net of offering costs, Shares Stock Issued During Period Shares At Registered Direct Offering Net Of Offering Costs Stock-based compensation Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value Change in unrealized gain (loss) on available-for-sale investments, net of tax Net loss Net loss Ending balance Ending balance, Shares Ending balance Operating lease right of use asset amortization. Increase (decrease) in operating lease liability. Proceeds from issuance of common stock under employee stock purchase plan. Proceeds from issuance of common stock through at market offering net of offering costs. Proceeds from issuance of common stock through registered direct offering, net of offering costs. Purchases of fixed assets included in accounts payable. Statement Of Cash Flows [Abstract] Cash flows from operating activities: Net Cash Provided By Used In Operating Activities [Abstract] Adjustments to reconcile net loss to net cash used in operating activities: Adjustments To Reconcile Net Income Loss To Cash Provided By Used In Operating Activities [Abstract] Depreciation and amortization Depreciation Depletion And Amortization Stock-based compensation Allocated Share Based Compensation Expense Debt discount accretion and non-cash interest expense Accretion Expense Amortization (accretion) of premium (discount) of available-for-sale investment securities Accretion Amortization Of Discounts And Premiums Investments Amortization of right-of-use assets Operating Lease Right Of Use Asset Amortization Loss (gain) on disposal of property and equipment Gain Loss On Sale Of Property Plant Equipment Changes in operating assets and liabilities: Increase Decrease In Operating Capital [Abstract] Other receivables Increase Decrease In Other Receivables Prepaid expenses and other assets Increase Decrease In Prepaid Deferred Expense And Other Assets Accounts payable and accrued expenses Increase Decrease In Accounts Payable And Accrued Liabilities Contract liability Increase Decrease In Contract With Customer Liability Operating lease liability Increase Decrease In Operating Lease Liability 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 property and equipment Payments To Acquire Property Plant And Equipment Purchases of available-for-sale investment securities Payments To Acquire Available For Sale Securities Debt Maturities of available-for-sale investment securities Proceeds From Sale And Maturity Of Available For Sale Securities Proceeds from sale of property and equipment Proceeds From Sale Of Property Plant And Equipment Net cash provided by 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 through employee stock purchase plan Proceeds From Issuance Of Common Stock Under Employee Stock Purchase Plan Proceeds from issuance of common stock through option exercises Proceeds From Issuance Of Shares Under Incentive And Share Based Compensation Plans Including Stock Options Proceeds from issuance of common stock through at the market offerings, net of offering costs Proceeds From Issuance Of Common Stock Through At Market Offering Net Of Offering Costs Proceeds from issuance of common stock through registered direct offering, net of offering costs Proceeds From Issuance Of Common Stock Through Registered Direct Offering Net Of Offering Costs Proceeds from issuance of common stock through underwritten follow-on offering, net of offering costs Proceeds From Issuance Of Common Stock Through Underwritten Follow On Offering Net Of Offering Costs Repayments on borrowings Repayments Of Debt Net cash provided by (used in) financing activities Net Cash Provided By Used In Financing Activities Net change in cash and cash equivalents Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect Cash and cash equivalents at beginning of period Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Including Disposal Group And Discontinued Operations Cash and cash equivalents at the end of period Supplemental disclosure of cash flow information: Supplemental Cash Flow Information [Abstract] Interest paid Interest Paid Net Purchase of fixed assets included in accounts payable Purchases Of Fixed Assets Included In Accounts Payable Accounting Policies [Abstract] Organization, Business and Basis of Presentation Organization Consolidation Basis Of Presentation Business Description And Accounting Policies [Text Block] Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Fair Value Disclosures [Abstract] Fair Value Measurements Fair Value Disclosures [Text Block] Entire disclosure of license, collaboration and other agreements. License agreement abstract. License Agreement [Abstract] License, Collaboration and Other Agreements License Collaboration And Other Agreements [Text Block] Balance sheet details. Balance Sheet Details [Abstract] Balance Sheet Details Supplemental Balance Sheet Disclosures [Text Block] Debt commitments and contingencies. Debt Instruments [Abstract] Debt, Commitments and Contingencies Debt Commitments And Contingencies [Text Block] Equity [Abstract] Stockholders' Equity Shareholders Equity And Share Based Payments [Text Block] Income Tax Disclosure [Abstract] Income Tax Income Tax Disclosure [Text Block] Compensation And Retirement Disclosure [Abstract] Employee Benefits Compensation And Employee Benefit Plans [Text Block] Subsequent Events [Abstract] Subsequent Events Subsequent Events [Text Block] Organization and Business Basis Of Accounting Policy Policy [Text Block] Principles of Consolidation Consolidation Policy [Text Block] Liquidity and financial condition. Liquidity and Financial Condition Liquidity And Financial Condition Policy [Text Block] Use of Estimates Use Of Estimates Reclassifications Prior Period Reclassification Adjustment Description Segment Reporting Segment Reporting Policy Policy [Text Block] Cash and Cash Equivalents Cash And Cash Equivalents Policy [Text Block] Investment Securities Investment Policy [Text Block] Concentration of Credit Risk Concentration Risk Credit Risk 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] accrued expenses. Accrued Expenses Accrued Expenses Policy [Text Block] Leases Lessor Leases Policy [Text Block] Revenue Recognition Revenue Recognition Policy [Text Block] Research and Development Costs Research And Development Expense Policy Patent Costs Legal Costs Policy [Text Block] Stock-Based Compensation Compensation Related Costs Policy [Text Block] Income Taxes Income Tax Policy [Text Block] Net Loss Per Share Earnings Per Share Policy [Text Block] Derivative Financial Instruments Derivatives Policy [Text Block] Recent Accounting Pronouncements New Accounting Pronouncements Policy Policy [Text Block] Schedule of Potentially Dilutive Securities Not Included in Calculation of Diluted Net Loss Per Share Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share [Text Block] Summary of Net Loss Per Share Schedule Of Earnings Per Share Basic And Diluted Table [Text Block] Schedule of Assets Measured at Fair Value on Recurring Basis Schedule Of Fair Value Assets And Liabilities Measured On Recurring Basis Table [Text Block] Schedule of Available-for-sale Investments Debt Securities Available For Sale Table [Text Block] Schedule of prepaid expenses. Schedule of Prepaid Expenses Schedule Of Prepaid Expenses Table [Text Block] Summary of Property and Equipment Property Plant And Equipment [Text Block] Summary of Accrued Expenses Schedule Of Accrued Liabilities Table [Text Block] Schedule of Future Minimum Payments under Non-cancelable Operating Lease and Reconciliation to Operating Lease Liability Schedule Of Future Minimum Rental Payments For Operating Leases Table [Text Block] Award Type Award Type [Axis] Award Type Share Based Compensation Arrangements By Share Based Payment Award Award Type And Plan Name [Domain] Employee Stock Option [Member] Employee Stock Option [Member] Summary of Stock Option Activity Schedule Of Share Based Compensation Stock Options Activity Table [Text Block] Summary of Assumptions Used to Determine Fair Value of Employee Stock Option Grants and Performance Options with Market Condition Schedule Of Share Based Payment Award Stock Options Valuation Assumptions Table [Text Block] Summary of Assumptions Used to Determine Fair Value of Employee Stock Purchase Plan Schedule Of Share Based Payment Award Employee Stock Purchase Plan Valuation Assumptions Table [Text Block] Schedule of Restricted Stock Units Activity Schedule Of Share Based Compensation Restricted Stock Units Award Activity Table [Text Block] Schedule of Allocation of Stock-Based Compensation for All Options Including Performance Options with Market Condition and Restricted Stock Units Schedule Of Compensation Cost For Share Based Payment Arrangements Allocation Of Share Based Compensation Costs By Plan Table [Text Block] Summary of Warrants Outstanding Schedule Of Stockholders Equity Note Warrants Or Rights [Text Block] Schedule of common stock reserved for future issuance. Summary of Common Stock Reserved for Future Issuance Schedule Of Common Stock Reserved For Future Issuance Table [Text Block] Schedule of Pretax Losses for Domestic and Foreign Operations Schedule Of Income Before Income Tax Domestic And Foreign Table [Text Block] Schedule of Reconciliations of the Expected Statutory Federal Income Tax Schedule Of Effective Income Tax Rate Reconciliation Table [Text Block] Schedule of Significant Components of Deferred Tax Assets Schedule Of Deferred Tax Assets And Liabilities Table [Text Block] Schedule of Activity Related to Unrecognized Tax Benefits Schedule Of Unrecognized Tax Benefits Roll Forward Table [Text Block] Description of business. Description of business. Description Of Business [Table] Description Of Business [Table] Ownership Ownership [Axis] Ownership Ownership [Domain] Pangu BioPharma Limited. Pangu BioPharma [Member] Pangu Bio Pharma Limited [Member] Geographical Statement Geographical [Axis] Geographical Segment Geographical [Domain] Hong Kong [Member] HONG KONG Transaction Type Transaction Type [Axis] Transaction Transaction [Domain] Purchase Agreement Member. Purchase Agreement [Member] Purchase Agreement [Member] Description Of Business [Line Items] Description Of Business [Line Items] Majority-owned subsidiary percentage Minority Interest Ownership Percentage By Parent Cash and cash equivalents and available for sale investments. Gross proceeds from market offering. Gross proceeds from agreements. Accumulated deficit Cash, cash equivalents and available-for-sale investments Cash And Cash Equivalents And Available For Sale Investments Milestone payment to be received Gross proceeds from market offering Gross Proceeds From Market Offering Gross proceeds from agreement Gross Proceeds From Agreements Number of operating segment Number Of Operating Segments Available for sale securities debt securities maturity period. Unrealized gain (loss) on amortized cost and fair value of investment securities. Significant account policies line items. Significant accounting policies. Significant Accounting Policies [Table] Significant Accounting Policies [Table] Statistical Measurement Range [Axis] Statistical Measurement Range [Member] Maximum [Member] Maximum [Member] Minimum [Member] Minimum [Member] Significant Accounting Policies [Line Items] Significant Accounting Policies [Line Items] Impairment charges on investment securities Other Than Temporary Impairment Loss Debt Securities Available For Sale Aggregate value of investment securities Available For Sale Securities Debt Securities Maturity period of investment securities Available For Sale Securities Debt Securities Maturity Period Unrealized gain between amortized cost and fair value of investment securities Unrealized Gain Loss On Amortized Cost And Fair Value Of Investment Securities Estimated useful life of property and equipment Property Plant And Equipment Useful Life Impairment of long lived assets Impairment Of Long Lived Assets Held For Use Percentage of tax benefit to be realized upon settlement Effective Income Tax Rate Reconciliation Tax Settlements Earnings Per Share [Abstract] 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] Class X convertible preferred stock (if-converted). Class X Preferred Stock (if-converted to common stock) [Member] Class X Convertible Preferred Stock If Converted [Member] Warrants for common stock. Common Stock Warrants [Member] Warrants For Common Stock [Member] Common stock options and restricted stock units. Common Stock Options and Restricted Stock Units [Member] Common Stock Options And Restricted Stock Units [Member] Employee stock purchase plan. Employee Stock Purchase Plan [Member] Employee Stock Purchase Plan [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 not included in calculation of diluted net loss per share Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount Shares Used In Computation Of Basic And Diluted Net Loss Per Share. Numerator: Net Income Loss Available To Common Stockholders Basic [Abstract] Denominator: Weighted Average Number Of Shares Outstanding [Abstract] Shares used in computing net loss per share, basic and diluted Shares Used In Computation Of Basic And Diluted Net Loss Per Share Net loss per share - basic and diluted Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Abstract] 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] 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] Quoted Prices in Active Markets for Identical Assets (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] Debt Security Category Information By Category Of Debt Security [Axis] Other than Temporary Impairment, Credit Losses Recognized in Earnings, Categories of Investments Other Than Temporary Impairment Credit Losses Recognized In Earnings Categories Of Investments [Domain] Available-for-sale [Member] Availableforsale Securities [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] Asset-backed Securities [Member] Asset Backed Securities [Member] Commercial Paper [Member] Commercial Paper [Member] Corporate Debt Securities [Member] Corporate Debt Securities [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 equivalents Cash And Cash Equivalents Fair Value Disclosure Investments, fair value Investments Fair Value Disclosure Total assets measured at fair value Assets Fair Value Disclosure Investments Debt And Equity Securities [Abstract] Schedule Of Available For Sale Securities [Table] Schedule Of Available For Sale Securities [Table] Financial Instrument Financial Instrument [Axis] Financial Instruments Transfers And Servicing Of Financial Instruments Types Of Financial Instruments [Domain] Schedule of Available-for-sale Securities [Line Items] Schedule Of Available For Sale Securities [Line Items] Gross Amortized Cost Available For Sale Debt Securities Amortized Cost Basis Gross Unrealized Gains Available For Sale Debt Securities Accumulated Gross Unrealized Gain Before Tax Gross Unrealized Losses Available For Sale Debt Securities Accumulated Gross Unrealized Loss Before Tax Market Value Remaining amount of receivable based on achievement of research milestones. Upfront payment received. Milestone payment received. Schedule Of Research And Development Arrangement Contract To Perform For Others [Table] Schedule Of Research And Development Arrangement Contract To Perform For Others [Table] Collaborative Arrangement and Arrangement Other than Collaborative Type Of Arrangement [Axis] Collaborative Arrangement and Arrangement Other than Collaborative Arrangements And Nonarrangement Transactions [Member] Development regulatory and sales milestone member. Development Regulatory And Sales Milestones [Member] Development Regulatory And Sales Milestone [Member] Counterparty Name Counterparty Name [Axis] Counterparty Name Repurchase Agreement Counterparty Name [Domain] Kyorin pharmaceutical co ltd . Kyorin Pharmaceutical Co Ltd [Member] Kyorin Pharmaceutical Co Ltd [Member] Subsequent Event Type Subsequent Event Type [Axis] Subsequent Event Type Subsequent Event Type [Domain] Subsequent Event [Member] Subsequent Event [Member] Balance Sheet Location Balance Sheet Location [Axis] Balance Sheet Location Balance Sheet Location [Domain] Other receivables. Other Receivables [Member] Other Receivables [Member] Research collaboration and license agreement. Development Regulatory And Sales Milestones [Member] Research Collaboration And License Agreement [Member] Collaboration revenue. Collaboration Revenue [Member] Collaboration Revenue [Member] Research collaboration and option agreement. Research Collaboration and Option Agreement [Member] Research Collaboration And Option Agreement [Member] CSL Behring. CSL Behring [Member] C S L Behring [Member] Hong kong university of science and technology. Hong Kong University of Science and Technology [Member] Hong Kong University Of Science And Technology [Member] Research And Development Arrangement Contract To Perform For Others [Line Items] Research And Development Arrangement Contract To Perform For Others [Line Items] Remaining receivable based on achievement of research milestones Remaining Amount Of Receivable Based On Achievement Of Research Milestones Upfront payment received Upfront Payment Received Milestone payments received Milestone Payment Received Stand-alone selling price of license Cost Of Revenue License and collaboration agreement revenue Revenue From Contract With Customer Including Assessed Tax Number of programs. Number of programs Number Of Programs Additional proceeds from research and development reimbursement from amendment. Agreement termination month and year. Additional proceeds from research and development reimbursement from amendment Additional Proceeds From Research And Development Reimbursement From Amendment Agreement termination Agreement Termination Month And Year Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date Revenue Remaining Performance Obligation Expected Timing Of Satisfaction Start Date [Axis] Performance obligations period Revenue Remaining Performance Obligation Expected Timing Of Satisfaction Period1 Additonal upfront payment received from amendment. Additional upfront payment received Additonal Upfront Payment Received From Amendment Collaborative agreement funding received. Collaborative agreement, funding received Collaborative Agreement Funding Received Funding of project cost, description Funding Of Project Cost Description Expenses Costs And Expenses Related Party Prepaid Expense Current [Abstract] Prepaid Expenses [Line Items] Prepaid Expenses [Table] Prepaid Expenses [Table] Prepaid Expenses [Table] Prepaid clinical and research expense. Prepaid Clinical and Research Expense [Member] Prepaid Clinical And Research Expense [Member] Prepaid manufacturing expenses. Prepaid Manufacturing Expenses [Member] Prepaid Manufacturing Expenses [Member] Other prepaid expenses. Other Prepaid Expenses [Member] Other Prepaid Expenses [Member] Prepaid Expenses [Line Items] Prepaid Expenses [Line Items] Property Plant And Equipment [Abstract] Schedule Of Property Plant And Equipment [Table] Schedule Of Property Plant And Equipment [Table] Long-Lived Tangible Asset Property Plant And Equipment By Type [Axis] Long-Lived Tangible Asset Property Plant And Equipment Type [Domain] Computer and office equipment. Computer and Office Equipment [Member] Computer And Office Equipment [Member] Scientific and laboratory equipment. Scientific and Laboratory Equipment [Member] Scientific And Laboratory Equipment [Member] Tenant improvements. Tenant Improvements [Member] Tenant 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 Property and equipment, Net Depreciation expense Accrued Liabilities Current [Abstract] Accrued salaries, wages and benefits Employee Related Liabilities Current Other accrued expenses Other Accrued Liabilities Current Accrued expenses Debt instrument number of tranches. Debt Instrument [Table] Debt Instrument [Table] Long-term Debt, Type Longterm Debt Type [Axis] Long-term Debt, Type Longterm Debt Type [Domain] Silicon Valley Bank and Solar Capital Ltd. loan and security agreement. Silicon Valley Bank and Solar Capital, Ltd. [Member] Silicon Valley Bank And Solar Capital Ltd Loan And Security Agreement [Member] Debt Instrument Debt Instrument [Axis] Debt Instrument, Name Debt Instrument Name [Domain] Term loan agreement tranche one. Term Loans Tranche One [Member] Term Loan Agreement Tranche One [Member] Term loan agreement tranche two. Term Loans Tranche Two [Member] Term Loan Agreement Tranche Two [Member] Term loan agreement tranche three. Term Loans Tranche Three [Member] Term Loan Agreement Tranche Three [Member] Loan amendment agreement with SVB And Solar. Loan Amendment Agreement with SVB and Solar [Member] Loan Amendment Agreement With S V B And Solar [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Available credit under loan and security agreement Line Of Credit Facility Maximum Borrowing Capacity Number of tranches Debt Instrument Number Of Tranches Loan and security agreement funded date Debt Instrument Offering Date1 Loan and security agreement, payment term Debt Instrument Payment Terms Percentage of funded amount for final payment. Percentage of funded amounts for final payment Percentage Of Funded Amount For Final Payment Class of warrant or rights warrant expiration period. Fair value of warrants. Warrants to purchase number of common stock, shares Class Of Warrant Or Right Number Of Securities Called By Warrants Or Rights Exercise price of warrant per share Class Of Warrant Or Right Exercise Price Of Warrants Or Rights1 Warrants expiration year Class Of Warrant Or Right Warrants Expiration Period Aggregate fair value of warrants using black scholes option pricing model Fair Value Of Warrants Lease extended maturity date. Lease space Area Of Land Lease extended maturity date Lease Extended Maturity Date Lease, option to extend Lessee Operating Lease Existence Of Option To Extend Operating lease expense Lease And Rental Expense Operating lease, weighted average remaining lease term Operating Lease Weighted Average Remaining Lease Term1 Operating lease, weighted average discount rate Operating Lease Weighted Average Discount Rate Percent Leases Operating [Abstract] 2021 Lessee Operating Lease Liability Payments Due Next Twelve Months 2022 Lessee Operating Lease Liability Payments Due Year Two 2023 Lessee Operating Lease Liability Payments Due Year Three Less: Amount representing interest Lessee Operating Lease Liability Undiscounted Excess Amount Present value of lease payments Operating Lease Liability Less: Current portion of operating lease liability Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table] Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table] Sale of Stock Subsidiary Sale Of Stock [Axis] Sale of Stock Sale Of Stock Name Of Transaction [Domain] At The Market Offering Program. ATM Offering Program [Member] At Market Offering Program [Member] Cowen Company, LLC (Cowen). Cowen Company, LLC (Cowen) [Member] Cowen Company Limited Liability Corporation [Member] Scenario Statement Scenario [Axis] Scenario Scenario Unspecified [Domain] Sales agreement. Sale Agreement [Member] Sales Agreement [Member] ATM offering program. ATM Offering Program [Member] A T M Offering Program [Member] H.C. Wainwright & Co., LLC Member. H.C. Wainwright & Co., LLC [Member] H C Wainwright Co L L C [Member] Public offerings member. Public Offerings [Member] Public Offerings [Member] Aspire capital member Aspire Capital [Member] Aspire Capital [Member] Plan Name Plan Name [Axis] Plan Name Plan Name [Domain] Two thousand fourteen stock option plan. 2014 Plan [Member] Two Thousand Fourteen Stock Option Plan [Member] IPO [Member] I P O [Member] Maximum [Member] 2015 Stock Option and Incentive Plan. 2015 Stock Option and Incentive Plan [Member] Two Thousand Fifteen Stock Option And Incentive Plan [Member] Vesting Vesting [Axis] Vesting Vesting [Domain] One Year Anniversary [Member] Share Based Compensation Award Tranche One [Member] 2015 Employee Stock Purchase Plan. 2015 Employee Stock Purchase Plan [Member] Two Thousand Fifteen Employee Stock Purchase Plan [Member] Restricted Stock Unit [Member] Restricted Stock Units R S U [Member] Share Based Compensation Arrangement By Share Based Payment Award [Line Items] Share Based Compensation Arrangement By Share Based Payment Award [Line Items] Agreed upon value of sale of common stock per transaction Common Stock Shares Subscriptions Shares issued during the period Stock Issued During Period Shares New Issues Shares issued, price per share Shares Issued Price Per Share Net proceeds from issuance of common stock Proceeds From Issuance Of Common Stock Commission rate equal to gross proceeds Commission rate equal to gross proceeds Commission Rate Equal To Gross Proceeds Number of shares issued and sold Issuance of additional share of common stock Stock Issued During Period Additional Share Of Common Stock1 Commitment to purchase shares Long Term Purchase Commitment Amount Long-term purchase commitment, period Longterm Purchase Commitment Period Long-term purchase commitment, description Long Term Purchase Commitment Description Stock option maximum term. Maximum term for stock option plan grant Stock Option Maximum Term Options vesting period Share Based Compensation Arrangement By Share Based Payment Award Award Vesting Period1 Effective date of plan. Additional common stock capital shares reserved for future issuance. Effective date of plan Effective Date Of Plan Number of common stock shares reserved for issuance Common Stock Capital Shares Reserved For Future Issuance Annual increase in shares authorized under plan, shares threshold Share Based Compensation Arrangement By Share Based Payment Award Other Share Increase Decrease Stock option grants description Share Based Compensation Arrangement By Share Based Payment Award Description Percentage threshold of outstanding shares as of December 31 of each year for calculation of annual increase in authorized shares under the plan Share Based Compensation Arrangement By Share Based Payment Award Percentage Of Outstanding Stock Maximum Additional number of common stock shares reserved for issuance Additional Common Stock Capital Shares Reserved For Future Issuance Option vesting percentage Sharebased Compensation Arrangement By Sharebased Payment Award Award Vesting Rights Percentage Options vesting period, description Share Based Compensation Arrangement By Share Based Payment Award Award Vesting Rights Number of Outstanding Options, Beginning Balance Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number Number of Outstanding Options, Granted Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross Number of Outstanding Options, Canceled/forfeited/expired Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures And Expirations In Period Number of Outstanding Options, Ending Balance Number of Outstanding Options, Vested and Expected to Vest, Ending Balance Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Outstanding Number Number of Outstanding Options, Exercisable, Ending Balance Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number Weighted Average Exercise Price, 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, Canceled/forfeited/expired Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures And Expirations In Period Weighted Average Exercise Price Weighted Average Exercise Price, Ending Balance Weighted Average Exercise Price, Options Vested and Expected to Vest, Ending Balance 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, Ending Balance Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price Weighted Average Contractual Term, Outstanding Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 Weighted Average Contractual Term, Options Vested and Expected to Vest Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested And Expected To Vest Outstanding Weighted Average Remaining Contractual Term1 Weighted Average Contractual Term, Options Exercisable Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Weighted Average Remaining Contractual Term1 Aggregate Intrinsic Value, Outstanding Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value Aggregate Intrinsic Value, Options Vested and 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 ESPP [Member] Employee Stock [Member] Expected term (in 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 Risk-free interest rate, minimum Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Risk Free Interest Rate Minimum Risk-free interest rate, maximum Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Risk Free Interest Rate Maximum Expected volatility Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate Expected volatility, minimum Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate Minimum Expected volatility, maximum Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate Maximum Expected dividend yield Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate Share based compensation arrangement by share based payment award, equity instruments other than options, released in period. 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] 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] Number of Outstanding Restricted Stock Units, Beginning Balance Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Number Number of Outstanding Restricted Stock Units, Granted Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Grants In Period Number of Outstanding Restricted Stock Units, Released Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Released In Period Number of Outstanding Restricted Stock Units, Forfeited Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Forfeited In Period Number of Outstanding Restricted Stock Units, Ending Balance Share based compensation arrangement by share based payment award, equity instruments other than options, released in period, weighted average grant date fair value. Weighted Average Grant Date Fair Value, 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, Released Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Released 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, Ending Balance Income Statement Location Income Statement Location [Axis] Income Statement Location Income Statement Location [Domain] Research and Development Expense [Member] Research And Development Expense [Member] General and Administrative Expense [Member] General And Administrative Expense [Member] Total stock-based compensation expense Weighted average grant date fair value of options granted Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Weighted Average Grant Date Fair Value Total grant date fair value of restricted stock units vested Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Vested In Period Total Fair Value Aggregate intrinsic value of stock options exercised Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value Aggregate intrinsic value of restricted stock units Sharebased Compensation Arrangement By Sharebased Payment Award Equity Instruments Other Than Options Aggregate Intrinsic Value Outstanding Unrecognized share based compensation expense related to unvested stock options Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Stock Options Unrecognized share based compensation expense related to restricted stock units Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Share Based Awards Other Than Options Unrecognized cost expected to be recognized over a weighted average period Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Period For Recognition1 Class of warrant or rights warrant expiration period. Warrants And Rights Note Disclosure [Abstract] Class Of Warrant Or Right [Table] Class Of Warrant Or Right [Table] Class of Warrant or Right Class Of Warrant Or Right [Axis] Class of Warrant or Right Class Of Warrant Or Right [Domain] Warrant one. Warrant One [Member] Warrant One [Member] Warrant two. Warrant Two [Member] Warrant Two [Member] Warrant three. Warrant Three [Member] Warrant Three [Member] Warrant four. Warrant Four [Member] Warrant Four [Member] Warrant five. Warrant Five [Member] Warrant Five [Member] Class Of Warrant Or Right [Line Items] Class Of Warrant Or Right [Line Items] Number Outstanding Class Of Warrant Or Right Outstanding Exercise Price Per Share Expiration Date Class Of Warrant Or Rights Warrant Expiration Period Two thousand fifteen stock plan. Shares Available Under the 2015 Plan [Member] Two Thousand Fifteen Stock Plan [Member] Common Stock Warrants [Member] Common stock reserved for future issuance United States Income Loss From Continuing Operations Before Income Taxes Domestic Foreign Income Loss From Continuing Operations Before Income Taxes Foreign Loss before income taxes Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest Income tax. Income tax. Income Tax [Table] Income Tax [Table] 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] Foreign [Member] Foreign Country [Member] Tax Credit Carryforward Tax Credit Carryforward [Axis] Tax Credit Carryforward, Name Tax Credit Carryforward Name [Domain] Orphan Drug Credits [Member] General Business [Member] CALIFORNIA CANADA Income Tax [Line Items] Income Tax [Line Items] Income tax (benefit) provision Income Tax Expense Benefit Expected income taxes benefit at federal statutory rate Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate State income taxes, net of federal benefit Income Tax Reconciliation State And Local Income Taxes Permanent items and other Income Tax Reconciliation Other Reconciling Items Stock compensation Income Tax Reconciliation Nondeductible Expense Share Based Compensation Cost Research credits Income Tax Reconciliation Tax Credits Research Unrecognized tax benefits Income Tax Reconciliation Tax Contingencies Foreign rate differential Income Tax Reconciliation Foreign Income Tax Rate Differential Change in tax rate Income Tax Reconciliation Change In Enacted Tax Rate Change in valuation allowance Income Tax Reconciliation Change In Deferred Tax Assets Valuation Allowance Income tax (benefit) expense Valuation allowance Deferred Tax Assets Valuation Allowance Deferred tax assets, tax credit carryforwards, research and other state. Deferred tax assets lease liability. Deferred tax assets: Deferred Tax Assets Net [Abstract] Net operating loss carryforwards Deferred Tax Assets Operating Loss Carryforwards Capitalized research and development expenses Deferred Tax Assets In Process Research And Development Research credits and other state credits Deferred Tax Assets Tax Credit Carryforwards Research And Other State Intangible assets Deferred Tax Assets Goodwill And Intangible Assets Reserve and accruals Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Share-based compensation expense Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Share Based Compensation Cost Lease liability Deferred Tax Assets Lease Liability Valuation allowance Total deferred tax assets Deferred Tax Assets Net Deferred tax liabilities: Deferred Tax Liabilities Net [Abstract] Right of use lease assets Deferred Tax Liabilities Leasing Arrangements Total deferred tax liabilities Deferred Tax Liabilities Net deferred tax assets Deferred Tax Assets Liabilities Net Operating loss carryforwards expiration year. NOLs carryforwards Operating Loss Carryforwards NOLs carryforwards not subject to expiration Deferred Tax Assets Operating Loss Carryforwards Not Subject To Expiration NOLs carryforwards subject to expiration Deferred Tax Assets Operating Loss Carryforwards Subject To Expiration NOLs carryforwards expiration year Operating Loss Carryforwards Expiration Year Deferred tax assets, tax credit carryforwards, research expiration year. Research and development credit carryforward Deferred Tax Assets Tax Credit Carryforwards Research Research and development credit carryforward expiration year Deferred Tax Assets Tax Credit Carryforwards Research Expiration Year Period of change in ownership. Percentage of change in ownership. Period of change in ownership Period Of Change In Ownership Percentage of change in ownership Percentage Of Change In Ownership Unrecognized tax benefits, income tax penalties and interest accrued Unrecognized Tax Benefits Income Tax Penalties And Interest Accrued Unrecognized tax benefits increase (decrease) resulting from prior period tax positions. Balance as of beginning of year Unrecognized Tax Benefits Increase related to prior year tax positions Unrecognized Tax Benefits Increase Decrease Resulting From Prior Period Tax Positions Increase related to current year tax positions Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions Balance as of end of year Change in unrecognized tax benefits Increase In Unrecognized Tax Benefits Is Reasonably Possible Maximum amount of tax offset by business credit. Maximum amount of tax offset by business credit Maximum Amount Of Tax Offset By Business Credit Defined contribution plan approved month and year. Defined contribution plan date of plan beginning. Defined Contribution Plan [Table] Defined Contribution Plan [Table] Retirement Plan Name Retirement Plan Name [Axis] Retirement Plan Name Retirement Plan Name [Domain] Four hundred one plan. 401 (k) Plan [Member] Four Hundred One Plan [Member] Defined Contribution Plan Disclosure [Line Items] Defined Contribution Plan Disclosure [Line Items] Policy approved month and year Defined Contribution Plan Approved Month And Year Date of Policy beginning Defined Contribution Plan Date Of Plan Beginning Percentage of match employee contribution Defined Contribution Plan Employer Matching Contribution Percent Of Match Percentage of participants's annual salary Defined Contribution Plan Maximum Annual Contributions Per Employee Percent Discretionary contribution Defined Contribution Plan Employer Discretionary Contribution Amount Subsequent Event [Table] Subsequent Event [Table] Asprire capital. Asprire Capital [Member] Asprire Capital [Member] Jones trading. Jones Trading [Member] Jones Trading [Member] Subsequent Event [Line Items] Subsequent Event [Line Items]