Revenue Recognition [Abstract] Collaborative Research and Development Agreements Collaborative Arrangement Disclosure [Text Block] Equity [Abstract] Schedule of Common Stock Reserved for Future Issuance Schedule Of Common Stock Reserved For Future Issuance [Table Text Block] Schedule Of Common Stock Reserved For Future Issuance [Table Text Block] Common stock, shares authorized (in shares) Common Stock, Shares Authorized Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Preferred stock, shares authorized (in shares) Preferred Stock, Shares Authorized Preferred stock, par value (in dollars per share) Preferred Stock, Par or Stated Value Per Share Common stock, shares issued (in shares) Common Stock, Shares, Issued Common stock, shares outstanding (in shares) Common Stock, Shares, Outstanding Schedule of Stock by Class [Table] Schedule of Stock by Class [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Common Stock Common Stock [Member] Class of Stock [Line Items] Class of Stock [Line Items] Warrants exercised, number of shares represented (as shares) Class Of Warrant Or Right, Number Of Securities Called By Warrants Or Rights Exercised Class Of Warrant Or Right, Number Of Securities Called By Warrants Or Rights Exercised Warrants exercised, number of shares represented, cashless exercise (as shares) Class Of Warrant Or Right, Number Of Securities Called By Warrants Or Rights Exercised, Non-cash Exercise Class Of Warrant Or Right, Number Of Securities Called By Warrants Or Rights Exercised, Non-cash Exercise Shares issued as a result of warrants exercised (in shares) Stock Issued During Period, Shares, Issued For Warrants Stock Issued During Period, Shares, Issued For Warrants Fair Value Disclosures [Abstract] Fair Value Measurements and Available for Sale Investments Fair Value Disclosures [Text Block] Debt Disclosure [Abstract] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Notes Payable to Banks Notes Payable to Banks [Member] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Loan and Security Agreement (LSA) Loan And Security Agreement [Member] Loan And Security Agreement [Member] Term A Loans Term A Loans [Member] Term A Loans [Member] Term B and Term C Loans Term B Loans And Term C Loans [Member] Term B Loans And Term C Loans [Member] Term B Loans Term B Loans [Member] Term B Loans [Member] Term C Loans Term C Loans [Member] Term C Loans [Member] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Series C Preferred Stock Series C Preferred Stock [Member] Class of Warrant or Right [Axis] Class of Warrant or Right [Axis] Class of Warrant or Right [Domain] Class of Warrant or Right [Domain] Term A Loan Warrants Term A Loan Warrants [Member] Term A Loan Warrants [Member] Term B And C Loans Warrants Term B And C Loans Warrants [Member] Term B And C Loans Warrants [Member] Derivative Instrument [Axis] Derivative Instrument [Axis] Derivative Contract [Domain] Derivative Contract [Domain] Warrants Warrant [Member] Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] 3-Month LIBOR London Interbank Offered Rate (LIBOR) [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Debt instrument, maximum borrowing capacity Debt Instrument, Maximum Borrowing Capacity Debt Instrument, Maximum Borrowing Capacity Number of loan installments (in installments) Debt Instrument, Number Of Loan Installments Debt Instrument, Number Of Loan Installments Aggregate borrowing capacity Debt Instrument, Face Amount Aggregate draw on term loan Proceeds from Notes Payable Fixed interest rate (as a percent) Debt Instrument, Interest Rate, Stated Percentage Number of shares called by warrants (in shares) Class of Warrant or Right, Number of Securities Called by Warrants or Rights Warrant exercise price (in dollars per share) Class of Warrant or Right, Exercise Price of Warrants or Rights U.S. treasury securities Derivative Liability Expected stock price volatility Fair Value Assumptions, Expected Volatility Rate Contractual term (in years) Fair Value Assumptions, Expected Term Risk-free interest rate Fair Value Assumptions, Risk Free Interest Rate Debt Instrument, Periodic Payment Terms, Balloon Payment to be Paid Debt Instrument, Periodic Payment Terms, Balloon Payment to be Paid Number of principal and interest payments (in payments) Debt Instrument, Periodic Payment, Number Of Principal And Interest Payments Debt Instrument, Periodic Payment, Number Of Principal And Interest Payments Basis spread on variable rate (as a percent) Debt Instrument, Basis Spread on Variable Rate Interest rate at period end (as a percent) Debt Instrument, Interest Rate At End Of Period Debt Instrument, Interest Rate At End Of Period Notes payable Notes Payable Debt instrument discounts Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net Notes payable, current portion Notes Payable, Current Effective interest rate Debt Instrument, Interest Rate, Effective Percentage Long-term Debt, Fiscal Year Maturity [Abstract] Long-term Debt, Fiscal Year Maturity [Abstract] Debt maturities in remainder of year Long-term Debt, Maturities, Repayments of Principal, Remainder of Fiscal Year 2019 Long-term Debt, Maturities, Repayments of Principal in Year Two 2020 Long-term Debt, Maturities, Repayments of Principal in Year Three Accounting Policies [Abstract] Schedule of Outstanding Potentially Dilutive Securities Excluded in the Calculation of Diluted Net Loss Per Share Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Income Tax Disclosure [Abstract] Tax Credit Carryforward [Table] Tax Credit Carryforward [Table] Income Tax Authority, Name [Axis] Income Tax Authority, Name [Axis] Income Tax Authority, Name [Domain] Income Tax Authority, Name [Domain] Australian Taxation Office Australian Taxation Office [Member] Consolidated Entities [Axis] Consolidated Entities [Axis] Consolidated Entities [Domain] Consolidated Entities [Domain] Subsidiaries Subsidiaries [Member] Tax Credit Carryforward [Line Items] Tax Credit Carryforward [Line Items] Refundable tax incentive for qualified research and development activities (as a percent) Research And Development Tax Incentive Credit, Percentage Research And Development Tax Incentive Credit, Percentage Research and development Research And Development Tax Incentive Credit Research And Development Tax Incentive Credit Australian tax incentive receivable Research And Development Tax Incentive Credit Receivable, Current Research And Development Tax Incentive Credit Receivable, Current Research and development tax incentive credit received during the period Research And Development Tax Incentive Credit Received During Period Research And Development Tax Incentive Credit Received During Period Deferred Revenue Arrangement, by Type [Table] Deferred Revenue Arrangement, by Type [Table] Counterparty Name [Axis] Counterparty Name [Axis] Counterparty Name [Domain] Counterparty Name [Domain] TESARO TESARO, Inc. And TESARO Development, Inc. [Member] TESARO, Inc. And TESARO Development, Inc. [Member] Celgene Corporation Celgene Corporation [Member] Celgene Corporation [Member] Type of Arrangement and Non-arrangement Transactions [Axis] Type of Arrangement and Non-arrangement Transactions [Axis] Arrangements and Non-arrangement Transactions [Domain] Arrangements and Non-arrangement Transactions [Domain] Collaborative Research And Development Agreement Collaborative Arrangement [Member] In Vivo Toxicology Studies Using GLPs In Vivo Toxicology Studies [Member] In Vivo Toxicology Studies [Member] IND clearance from the FDA Clearance Of Investigational New Drug From FDA [Member] Clearance Of Investigational New Drug From FDA [Member] Phase 2 clinical trial initiation Phase 2 Clinical Trial Initiation [Member] Phase 2 Clinical Trial Initiation [Member] Phase 1 clinical trial initiation Phase 1 Clinical Trial Initiation [Member] Phase 1 Clinical Trial Initiation [Member] Products and Services [Axis] Products and Services [Axis] Products and Services [Domain] Products and Services [Domain] AnaptysBio-generated Anti-PD-1 Antagonist Antibody (TSR-042) AnaptysBio-generated Anti-PD-1 Antagonist Antibody (TSR-042) [Member] AnaptysBio-generated Anti-PD-1 Antagonist Antibody (TSR-042) [Member] AnaptysBio Generated Anti-TIM3 Antagonist Antibody (TSR-022) AnaptysBio Generated Anti-TIM3 Antagonist Antibody (TSR-022) [Member] AnaptysBio Generated Anti-TIM3 Antagonist Antibody (TSR-022) [Member] AnaptysBio Generated Anti-LAG3 Antagonist Antibody (TSR-033) AnaptysBio Generated Anti-LAG3 Antagonist Antibody (TSR-033) [Member] AnaptysBio Generated Anti-LAG3 Antagonist Antibody (TSR-033) [Member] AnaptysBio-Generated Anti-PD-1 Antagonist Antibody (CC-90006) AnaptysBio-Generated Anti-PD-1 Antagonist Antibody (CC-90006) [Member] AnaptysBio-Generated Anti-PD-1 Antagonist Antibody (CC-90006) [Member] Deferred Revenue Arrangement [Line Items] Deferred Revenue Arrangement [Line Items] Upfront license fee received Revenue Recognition, Multiple-deliverable Arrangements, Upfront Fee Received Revenue Recognition, Multiple-deliverable Arrangements, Upfront Fee Received Number of outstanding research and development targets Revenue Recognition, Milestone Method, Number Of Outstanding Research And Development Targets Revenue Recognition, Milestone Method, Number Of Outstanding Research And Development Targets Milestone payments, contingent upon preclinical and clinical trial events (up to) Revenue Recognition, Milestone Method, Contingent Upon Preclinical And Clinical Trial Events Revenue Recognition, Milestone Method, Contingent Upon Preclinical And Clinical Trial Events Milestone payments, contingent upon certain U.S. and European regulatory submissions and approvals (up to) Revenue Recognition, Milestone Method, Contingent Upon Certain United States And European Regulatory Submissions And Approvals Revenue Recognition, Milestone Method, Contingent Upon Certain United States And European Regulatory Submissions And Approvals Milestone payments, contingent upon achievement of specified levels of worldwide sales (up to) Revenue Recognition, Milestone Method, Contingent Upon Achievement Of Specified Levels Of Worldwide Sales Revenue Recognition, Milestone Method, Contingent Upon Achievement Of Specified Levels Of Worldwide Sales Agreement term following first commercial sale or expiration of the last to expire patent (in years) Revenue Recognition, Milestone Method, Agreement Term Following First Commercial Sale Or Expiration Of The Last To Expire Patent Revenue Recognition, Milestone Method, Agreement Term Following First Commercial Sale Or Expiration Of The Last To Expire Patent Milestones achieved during period, amount Revenue Recognition, Milestone Method, Milestones Achieved During The Period, Amount Revenue Recognition, Milestone Method, Milestones Achieved During The Period, Amount Collaboration revenue Revenue, Net Maximum milestone payments per target Revenue Recognition, Milestone Method, Maximum Revenue Per Milestone Revenue Recognition, Milestone Method, Maximum Revenue Per Milestone Milestone payment earned Revenue Recognized, Milestone Method, Milestone Payment Earned Revenue Recognized, Milestone Method, Milestone Payment Earned Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Fair Value, Measurements, Recurring Fair Value, Measurements, Recurring [Member] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Quoted Market Prices for Identical Assets (Level 1) Fair Value, Inputs, Level 1 [Member] Significant Other Observable Inputs (Level 2) Fair Value, Inputs, Level 2 [Member] Significant Unobservable Inputs (Level 3) Fair Value, Inputs, Level 3 [Member] Cash and Cash Equivalents [Axis] Cash and Cash Equivalents [Axis] Cash and Cash Equivalents [Domain] Cash and Cash Equivalents [Domain] Money market funds Money Market Funds [Member] Mutual funds Mutual Fund [Member] Financial Instrument [Axis] Financial Instrument [Axis] Financial Instruments [Domain] Financial Instruments [Domain] U.S. treasury securities US Treasury Securities [Member] Agency securities US Government Agencies Debt Securities [Member] Commercial and corporate obligations Commercial And Corporate Obligations [Member] Commercial And Corporate Obligations [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] Investments at fair value Cash And Cash Equivalents And Restricted Cash, Fair Value Disclosure Cash And Cash Equivalents And Restricted Cash, Fair Value Disclosure Available-for-sale securities, debt securities Available-for-sale Securities, Debt Securities Disclosure of Compensation Related Costs, Share-based 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] Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] 2017 Equity Incentive Plan Equity Incentive Plan, 2017 [Member] Equity Incentive Plan, 2017 [Member] Employee Stock Purchase Plan Employee Stock Purchase Plan, 2017 [Member] Employee Stock Purchase Plan, 2017 [Member] Award Type [Axis] Award Type [Axis] Equity Award [Domain] Equity Award [Domain] Formerly Issuable Common Shares Formerly Issuable Common Shares [Member] Formerly Issuable Common Shares [Member] Employee Stock Employee Stock [Member] Employee and Nonemployee Stock Options Employee And Nonemployee Stock Options [Member] Employee And Nonemployee Stock Options [Member] Options Employee Stock Option [Member] Title of Individual [Axis] Title of Individual [Axis] Relationship to Entity [Domain] Relationship to Entity [Domain] Director Director [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 reserved for issuance (in shares) Common Stock, Capital Shares Reserved for Future Issuance Annual increase in number of shares available for issuance (as a percent) Common Stock, Capital Shares Reserved For Future Issuance, Annual Increase, Percent Of Aggregate Shares Outstanding Common Stock, Capital Shares Reserved For Future Issuance, Annual Increase, Percent Of Aggregate Shares Outstanding Capital shares reserved for future issuance, increase (in shares) Common Stock, Capital Shares Reserved For Future Issuance, Increase Common Stock, Capital Shares Reserved For Future Issuance, Increase Stock options outstanding (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Shares reserved for future award grants (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Award vesting period (in years) Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Award expiration period (in years) Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period Proceeds from issuance of common stock, upon the exercise of stock options Proceeds from Stock Options Exercised Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross Unrecognized compensation cost Employee And Nonemployee Service Share-based Compensation, Nonvested Awards, Compensation Not Yet Recognized, Stock Options Employee And Nonemployee Service Share-based Compensation, Nonvested Awards, Compensation Not Yet Recognized, Stock Options Weighted average period remaining for amortization of unrecognized compensation cost (in years) Employee And Nonemployee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not Yet Recognized, Period For Recognition Employee And Nonemployee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not Yet Recognized, Period For Recognition Stockholders' Equity Stockholders' Equity Note Disclosure [Text Block] Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Table] Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Table] Liability Class [Axis] Liability Class [Axis] Fair Value by Liability Class [Domain] Fair Value by Liability Class [Domain] Derivative Financial Instruments, Liabilities Derivative Financial Instruments, Liabilities [Member] Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items] Fair value of preferred stock (in dollars per share) Share Price Exercise price (in dollars per share) Fair Value Assumptions, Exercise Price Volatility Dividend Yield Fair Value Assumptions, Expected Dividend Rate Weighted-average measurement date fair value per share (in dollars per share) Fair Value Assumptions, Weighted Average Grant Date Fair Value Per Share Fair Value Assumptions, Weighted Average Grant Date Fair Value Per Share Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Beginning balance Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value Net gains (losses) included in other expense Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings Reclassification of warrant liabilities to equity Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers out of Level 3 Ending balance Equity Incentive Plans Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Statement of Cash Flows [Abstract] CASH FLOWS FROM OPERATING ACTIVITIES: Net Cash Provided by (Used in) Operating Activities [Abstract] Net loss Net Income (Loss) Attributable to Parent 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 Share-based Compensation And Issuance Of Stock And Warrants For Services Or Claims Share-based Compensation And Issuance Of Stock And Warrants For Services Or Claims Change in fair value of liability for preferred stock warrants Fair Value Adjustment of Warrants (Income) loss from investments Available-for-sale Securities, Gross Realized Gain (Loss), Excluding Other than Temporary Impairments Non-cash interest expense Other Noncash Income (Expense) Changes in operating assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Receivable from collaborative partners Increase (Decrease) in Contract Receivables, Net Australian tax incentive receivable Increase (Decrease) in Income Taxes Receivable Prepaid expenses and other assets Increase (Decrease) in Prepaid Expense and Other Assets Accounts payable and other liabilities Increase (Decrease) in Accounts Payable and Accrued 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] Acquisition of investments Payments to Acquire Available-for-sale Securities, Debt Sales and maturities of investments Proceeds from Sale and Maturity of Available-for-sale Securities Purchases of property and equipment Payments to Acquire Property, Plant, and Equipment Net cash provided by (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 public offerings, net of underwriters' fees Proceeds from Issuance of Common Stock Proceeds from issuance of common stock, upon the exercise of warrants Proceeds from Warrant Exercises Payments on notes payable Repayments of Notes Payable Payments for offering costs Payments of Stock Issuance Costs Net cash (used in) provided by financing activities Net Cash Provided by (Used in) Financing Activities Net (decrease) increase in cash, cash equivalents, and restricted cash Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect Cash, cash equivalents and restricted cash, beginning of period Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Cash, cash equivalents and restricted cash, end of period SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION Supplemental Cash Flow Information [Abstract] Interest paid Interest Paid Non-cash investing and financing activities: Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Amounts accrued for property and equipment Capital Expenditures Incurred but Not yet Paid Amounts accrued for offering costs Stock Issuance Costs Incurred During Noncash Transaction Stock Issuance Costs Incurred During Noncash Transaction Reclassification of warrants to equity Transfer Of Warrants To Equity Transfer Of Warrants To Equity Organization, Consolidation and Presentation of Financial Statements [Abstract] Accumulated Deficit Retained Earnings (Accumulated Deficit) Class of Warrant or Right [Table] Class of Warrant or Right [Table] Sale of Stock [Axis] Sale of Stock [Axis] Sale of Stock [Domain] Sale of Stock [Domain] IPO IPO [Member] Underwriters' option Over-Allotment Option [Member] Convertible preferred stock Convertible Preferred Stock [Member] Class of Warrant or Right [Line Items] Class of Warrant or Right [Line Items] Common shares issued during initial public offering (in shares) Stock Issued During Period, Shares, New Issues Initial public offering, share price (in dollars per share) Shares Issued, Price Per Share Proceeds from initial public offering, net of underwriters fees Proceeds from Issuance Initial Public Offering Convertible preferred stock, converted to common stock (in shares) Stock Issued During Period, Shares, Conversion of Convertible Securities Reverse stock split, conversion ratio Stockholders' Equity Note, Stock Split, Conversion Ratio Number of reportable segments Number of Reportable Segments Statement of Financial Position [Abstract] Preferred stock, shares issued (in shares) Preferred Stock, Shares Issued Preferred stock, shares outstanding (in shares) Preferred Stock, Shares Outstanding Balance Sheet Related Disclosures [Abstract] Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Domain] Laboratory equipment Laboratory Equipment [Member] Laboratory Equipment [Member] Office furniture and equipment Office Equipment [Member] Leasehold improvements Leasehold Improvements [Member] Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Property and equipment, gross Property, Plant and Equipment, Gross Less: accumulated depreciation and amortization Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Total property and equipment, net Property, Plant and Equipment, Net Notes Payable Debt Disclosure [Text Block] Issued and Outstanding: Common Stock, Number of Shares, Par Value and Other Disclosures [Abstract] Warrant for shares of common stock (in shares) Common stock, shares reserved for issuance (in shares) Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] 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 [Axis] Antidilutive Securities [Axis] Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Dilutive securities excluded from computation of net loss per share (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Summary of Activity Related to Stock Option Awards Share-based Compensation, Stock Options, Activity [Table Text Block] Summary of Weighted Average Assumptions in Stock Option Valuations Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Summary of Non-cash Stock-based Compensation Expense Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan [Table Text Block] Balance Sheet Accounts and Supplemental Disclosures Supplemental Balance Sheet Disclosures [Text Block] Document and Entity Information [Abstract] Document and Entity Information [Abstract] Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category 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 Amendment Flag Amendment Flag Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Accrued compensation and related expenses Employee-related Liabilities, Current Accrued research and contract manufacturing expenses Accrued Research And Contract Manufacturing Expenses, Current Accrued Research And Contract Manufacturing Expenses, Current Other Other Accrued Liabilities, Current Total accrued expenses Accrued Liabilities, Current Schedule of Collaborative Arrangements and Non-collaborative Arrangement Transactions Schedule of Collaborative Arrangements and Non-collaborative Arrangement Transactions [Table Text Block] Australia Research and Development Tax Incentive Income Tax Disclosure [Text Block] Shares Subject to Options Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Stock options outstanding, beginning balance (in shares) Exercises (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Forfeitures and cancellations (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period Stock options outstanding, ending balance (in shares) Stock options exercisable, ending balance (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Weighted-Average Exercise Price per Share Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Stock options outstanding, beginning balance (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Granted (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Exercises (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Forfeitures and cancellations (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price Stock options outstanding, ending balance (in dollars per share) Stock options exercisable, ending balance (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Weighted-Average Remaining Contractual Term and Aggregate Intrinsic Value Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract] Weighted average remaining contractual term, options outstanding (in years) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Weighted average remaining contractual term, options exercisable (in years) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term Aggregate intrinsic value, options outstanding Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value Aggregate intrinsic value, options exercisable Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value 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 Expected term (in years) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term Weighted average grant date fair value per share (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value Property and Equipment Property, Plant and Equipment [Table Text Block] Schedule of Accrued Expenses Schedule of Accrued Liabilities [Table Text Block] ASSETS Assets [Abstract] Current assets: Assets, Current [Abstract] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Short-term investments Available-for-sale Securities, Debt Securities, Current Prepaid expenses and other current assets Prepaid Expense and Other Assets, Current Total current assets Assets, Current Property and equipment, net Long-term investments Available-for-sale Securities, Debt Securities, Noncurrent Other long-term assets Other Assets, Noncurrent Restricted cash Restricted Cash and Cash Equivalents, Noncurrent Total assets Assets LIABILITIES, PREFERRED STOCK AND STOCKHOLDERS’ EQUITY Liabilities and Equity [Abstract] Current liabilities: Liabilities, Current [Abstract] Accounts payable Accounts Payable, Current Accrued expenses Other current liabilities Other Liabilities, Current Total current liabilities Liabilities, Current Notes payable, net of current portion Notes Payable to Bank, Noncurrent Deferred rent Accrued Rent, Noncurrent Stockholders’ equity: Stockholders' Equity Attributable to Parent [Abstract] Preferred stock, $0.001 par value, 10,000 shares authorized and no shares, issued or outstanding at March 31, 2018 and December 31, 2017, respectively Preferred Stock, Value, Issued Common stock, $0.001 par value, 500,000 shares authorized, 23,817 shares and 23,791 shares issued and outstanding at March 31, 2018 and December 31, 2017, respectively Common Stock, Value, Issued Additional paid in capital Additional Paid in Capital Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Accumulated deficit Total stockholders’ equity Stockholders' Equity Attributable to Parent Total liabilities, preferred stock and stockholders’ equity Liabilities and Equity Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Research and development Research and Development Expense [Member] General and administrative General and Administrative Expense [Member] Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Measurement Basis [Axis] Measurement Basis [Axis] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Portion at Fair Value Measurement Portion at Fair Value Measurement [Member] Carrying Amount Reported Value Measurement [Member] Fair Value Estimate of Fair Value Measurement [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Notes payable Notes Payable, Fair Value Disclosure Description of the Business Nature of Operations [Text Block] Schedule of Assets and Liabilities that Require Fair Value Measurements on a Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Schedule of Weighted-average Assumptions for Liabilities for Series C Preferred Stock Warrants Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Table Text Block] Summary of Activity in Liabilities Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Fair Value of Other Financial Instruments Fair Value, by Balance Sheet Grouping [Table Text Block] Available-for-sale Investments Schedule of Available-for-sale Securities Reconciliation [Table Text Block] Schedule of Available-for-sale Securities [Table] Schedule of Available-for-sale Securities [Table] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Domain] Major Types of Debt and Equity Securities [Domain] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum Minimum [Member] Maximum Maximum [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 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 Total Fair Value Available for Sale investments, current Available-for-sale Securities, Current Investments outstanding, maturity date range (in years) Available-for-sale Debt Securities, Remaining Maturity Available-for-sale Debt Securities, Remaining Maturity Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Basis of Consolidation Consolidation, Policy [Policy Text Block] Use of Estimates Use of Estimates, Policy [Policy Text Block] Revenue Recognition Revenue Recognition, Policy [Policy Text Block] Net Loss Per Common Share Earnings Per Share, Policy [Policy Text Block] Accounting Pronouncements Recently Adopted and Recent Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Income Statement [Abstract] Operating expenses: Operating Expenses [Abstract] Research and development Research and Development Expense General and administrative General and Administrative Expense Total operating expenses Operating Expenses Loss from operations Operating Income (Loss) Other income (expense), net Nonoperating Income (Expense) [Abstract] Interest expense Interest Expense Change in fair value of liability for preferred stock warrants Interest income Interest Income (Expense), Nonoperating, Net Other income (expense), net Other Nonoperating Income (Expense) Total other income (expense), net Nonoperating Income (Expense) Net loss Unrealized loss on available for sale securities Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax Other comprehensive loss Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Comprehensive loss Comprehensive Income (Loss), Net of Tax, Attributable to Parent Net loss per common share: Earnings Per Share, Basic and Diluted [Abstract] Basic and diluted (in dollars per share) Earnings Per Share, Basic and Diluted Weighted-average number of shares outstanding: Earnings Per Share, Basic and Diluted, Other Disclosures [Abstract] Basic and diluted (in shares) Weighted Average Number of Shares Outstanding, Basic and Diluted