SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION Supplemental Cash Flow Information [Abstract] Net Loss Per Common Share Earnings Per Share, Policy [Policy Text Block] Vested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Leasehold improvements Leasehold Improvements [Member] Net loss Net loss Net loss Net Income (Loss) Attributable to Parent Operating lease right-of-use assets Operating Lease, Right-of-Use Asset Short-term investments Debt Securities, Available-for-sale, Current Preferred stock, shares outstanding (in shares) Preferred Stock, Shares Outstanding Accrued compensation and related expenses Employee-related Liabilities, Current Income Statement Location [Axis] Income Statement Location [Axis] Statistical Measurement [Domain] Statistical Measurement [Domain] Receivables from collaborative partners Increase (Decrease) in Contract with Customer, Asset Security Exchange Name Security Exchange Name Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Cancelled (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Schedule of Royalty Transaction Activity Contract with Customer, Contract Asset, Contract Liability, and Receivable [Table Text Block] Weighted average remaining lease term (in years) Operating Lease, Weighted Average Remaining Lease Term Other long-term assets Other Assets, Noncurrent Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Liabilities Related To Sale Of Future Royalties [Line Items] Liabilities Related To Sale Of Future Royalties [Line Items] Liabilities Related To Sale Of Future Royalties Expected dividend yield Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate Shares reserved for future award grants (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant By the end of 2026 First Installment [Member] First Installment Net (decrease) increase in cash and cash equivalents Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Entity File Number Entity File Number Expected volatility Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate Issued and Outstanding: Common Stock, Number of Shares, Par Value and Other Disclosures [Abstract] Forfeitures and cancellations (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period Certificates of deposit Certificates of Deposit [Member] Interest income Interest Income, Other Lessee, Lease, Description [Line Items] Lessee, Lease, Description [Line Items] Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] Weighted-average discount rate (as a percent) Operating Lease, Weighted Average Discount Rate, Percent Options to purchase common stock (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Research and development Research and Development Expense [Member] Aggregate Intrinsic Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value [Abstract] Subsequent Events [Abstract] Subsequent Events [Abstract] GSK GlaxoSmithKline [Member] GlaxoSmithKline Granted (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value First MAA approval - first indication First Marketing Authorization Application Approval - First Indication [Member] First Marketing Authorization Application Approval - First Indication Title of Individual [Domain] Title of Individual [Domain] Award Type [Domain] Award Type [Domain] IND clearance from the FDA Clearance Of Investigational New Drug From FDA [Member] Clearance Of Investigational New Drug From FDA [Member] Local Phone Number Local Phone Number Monthly base rate (usd per sqft) Rent Per Square Foot Rent Per Square Foot ASSETS Assets [Abstract] Schedule of Available-for-sale Investments Schedule of Available-for-sale Securities Reconciliation [Table Text Block] Weighted-Average Remaining Contractual Term and Aggregate Intrinsic Value Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract] Stock options exercisable, ending balance (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Remaining maturity (in years) Available-for-sale Debt Securities, Remaining Maturity Available-for-sale Debt Securities, Remaining Maturity Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Maximum milestone payments per target (up to) Revenue Recognition, Milestone Method, Maximum Revenue Per Milestone Revenue Recognition, Milestone Method, Maximum Revenue Per Milestone Preferred stock, $0.001 par value, 10,000 shares authorized and no shares, issued or outstanding at March 31, 2022 and December 31, 2021, respectively Preferred Stock, Value, Issued Stock options issued and outstanding (in shares) Stock options outstanding, beginning balance (in shares) Stock options outstanding, ending balance (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Accumulated Deficit Retained Earnings [Member] Deferred Revenue Arrangement, by Type [Table] Deferred Revenue Arrangement, by Type [Table] Prepaid expenses and other assets Increase (Decrease) in Prepaid Expense and Other Assets Lease term (in months) Lessee, Operating Lease, Lease Not yet Commenced, Term of Contract Area of leased property (sqft) Area of Real Estate Property Royalty Agreement, Above $1. 0 billion Royalty Agreement, Above $1. 0 billion [Member] Royalty Agreement, Above $1. 0 billion Other Liabilities Disclosure [Abstract] Commitments and Contingencies Commitments and Contingencies Disclosure [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] 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 Amounts accrued for property and equipment Capital Expenditures Incurred but Not yet Paid Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Filing of the first BLA - second indication Filing of Biologics License Application - Second Indication [Member] Filing of Biologics License Application - Second Indication Basic (in usd per share) Earnings Per Share, Basic Royalty Purchase Agreement Royalty Purchase Agreement [Member] Royalty Purchase Agreement Thereafter Lessee, Operating Lease, Liability, to be Paid, after Year Four Lessee, Operating Lease, Liability, to be Paid, after Year Four 2025 Lessee, Operating Lease, Liability, to be Paid, Year Three First BLA approval - first indication First Biologics License Application Approval - dMMREC [Member] First Biologics License Application Approval - dMMREC Number of shares, beginning balance (in shares) Number of shares, ending balance (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number BMS Bristol-Myers Squibb [Member] Bristol-Myers Squibb Number of Shares Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Cash paid for amounts included in the measurement of lease liabilities Operating Lease, Payments Non-cash interest expense Other Noncash Income (Expense) Receivables from collaborative partners Receivables, Net, Current Plan Name [Axis] Plan Name [Axis] Quoted Market Prices for Identical Assets (Level 1) Fair Value, Inputs, Level 1 [Member] CASH FLOWS FROM INVESTING ACTIVITIES: Net Cash Provided by (Used in) Investing Activities [Abstract] Weighted-average number of shares outstanding: Earnings Per Share, Basic and Diluted, Other Disclosures [Abstract] Liabilities Related To Sale Of Future Royalties [Table] Liabilities Related To Sale Of Future Royalties [Table] Liabilities Related To Sale Of Future Royalties Entity Small Business Entity Small Business 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 Total liabilities and stockholders’ equity Liabilities and Equity Other Other Accrued Liabilities, Current Sales and maturities of investments Proceeds from Sale and Maturity of Debt Securities, Available-for-sale Exercises (in usd per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Additional paid in capital Additional Paid in Capital Agency securities US Government Agencies Debt Securities [Member] Lessee, Lease, Description [Table] Lessee, Lease, Description [Table] Deferred Revenue Arrangement [Line Items] Deferred Revenue Arrangement [Line Items] Proceeds from sale of future royalties Proceeds From Advance Future Royalties Proceeds From Advance Future Royalties LIABILITIES AND STOCKHOLDERS’ EQUITY Liabilities and Equity [Abstract] Royalties Royalty Agreement [Member] Royalty Agreement Operating expenses: Operating Expenses [Abstract] Anti-LAG-3 (GSK40974386) AnaptysBio Generated Anti-LAG-3 (GSK40974386) [Member] AnaptysBio Generated Anti-LAG-3 (GSK40974386) AnaptysBio-generated Anti-PD-1 Antagonist Antibody (TSR-042) AnaptysBio-Generated Anti-PD-1 Antagonist Antibody (CC-90006) [Member] AnaptysBio-Generated Anti-PD-1 Antagonist Antibody (CC-90006) [Member] Entity Interactive Data Current Entity Interactive Data Current Cash and Cash Equivalents [Domain] Cash and Cash Equivalents [Domain] Shares issued under employee stock plans Stock Issued During Period, Value, Stock Options Exercised Minimum Minimum [Member] Sagard Sagard Healthcare Royalty Partners, LP [Member] Sagard Healthcare Royalty Partners, LP 2024 Lessee, Operating Lease, Liability, to be Paid, Year Two Royalties and milestones, agreement amount to be received Advance Future Royalties, Aggregate Payment, Threshold Advance Future Royalties, Aggregate Payment, Threshold Forfeitures and cancellations (in usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price Preferred stock, shares authorized (in shares) Preferred Stock, Shares Authorized Laboratory equipment Laboratory Equipment [Member] Laboratory Equipment [Member] Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Gross Unrealized Gains Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax Entity Address, State or Province Entity Address, State or Province Fair Value Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer Current liabilities: Liabilities, Current [Abstract] Operating lease liabilities Increase (Decrease) in Operating Lease Liability Non cash share based compensation expense Share-based Payment Arrangement, Accelerated Cost General and administrative General and Administrative Expense Stockholders' Equity, Beginning Balance (in shares) Stockholders' Equity, Ending Balance (in shares) Shares, Outstanding Stock options exercisable, ending balance (in usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Award equivalent shares Share-based Compensation Arrangement by Share-based Payment Award, Common Share Equivalent Share-based Compensation Arrangement by Share-based Payment Award, Common Share Equivalent Equity Incentive Plans Share-based Payment Arrangement [Text Block] Significant Unobservable Inputs (Level 3) Fair Value, Inputs, Level 3 [Member] Accounting Policies [Abstract] Accounting Policies [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 AnaptysBio-generated Zejula and JEMPERLI Zejula and AnaptysBio-generated JEMPERLI [Member] Zejula and AnaptysBio-generated JEMPERLI Number of reportable segments Number of Reportable Segments Internal rate of return (as a percent) Advance Future Royalties, Internal Rate Of Return Advance Future Royalties, Internal Rate Of Return Accrued professional fees Accrued Professional Fees, Current Lease liability Total Operating Lease, Liability Document Transition Report Document Transition Report Common stock, $0.001 par value, 500,000 shares authorized, 28,178 shares and 27,647 shares issued and outstanding at March 31, 2022 and December 31, 2021, respectively Common Stock, Value, Issued Total other income (expense), net Nonoperating Income (Expense) Weighted average period remaining for amortization of unrecognized compensation cost (in years) Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition Weighted average grant date fair value, beginning balance (in dollars per share) Weighted average grant date fair value, ending balance (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Proceeds, contingent on annual sales milestones upfront (as a percent) Advance Future Royalties, Aggregate Payment, Threshold Percent Advance Future Royalties, Aggregate Payment, Threshold Percent Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Entity Emerging Growth Company Entity Emerging Growth Company 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 2022 Lessee, Operating Lease, Liability, to be Paid, Remainder of Fiscal Year Payments for debt issuance costs Payments of Debt Issuance Costs Schedule of Weighted Average Assumptions used to Estimate Fair Value Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Cover [Abstract] Cover [Abstract] Schedule of Unrealized Loss and Fair Values in a Loss Position Schedule of Unrealized Loss on Investments [Table Text Block] Collaborative Arrangement and Arrangement Other than Collaborative [Axis] Collaborative Arrangement and Arrangement Other than Collaborative [Axis] Less imputed interest Lessee, Operating Lease, Liability, Undiscounted Excess Amount Net sales royalty Net Sales Royalty Threshold Net Sales Royalty Threshold Prepaid expenses and other current assets Prepaid Expense and Other Assets, Current Financial Instrument [Axis] Financial Instrument [Axis] Accrued expenses Total accrued expenses Accrued Liabilities, Current Collaboration revenue Collaboration revenue Revenue from Contract with Customer, Excluding Assessed Tax Office furniture and equipment Office Equipment [Member] Options to purchase common stock Stock Options Share-based Payment Arrangement, Option [Member] Regulatory Regulatory [Member] Regulatory Equity [Abstract] Equity [Abstract] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Document Quarterly Report Document Quarterly Report Fair Value Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months Common Stock Common Stock [Member] Loss from operations Operating Income (Loss) Zejula Zejula [Member] Zejula Sale of Future Royalties Sale Of Future Royalties Text Block [Text Block] Sale Of Future Royalties Text Block Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Debt Securities, Available-for-sale [Line Items] Debt Securities, Available-for-sale [Line Items] Current portion of operating lease liability Operating Lease, Liability, Current Gross Unrealized Losses Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax Collaborative Research and Development Agreements Collaborative Arrangement Disclosure [Text Block] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Document Fiscal Year Focus Document Fiscal Year Focus Stock-based compensation Non-cash stock-based compensation cost Share-based Payment Arrangement, Noncash Expense Additional Paid-in Capital Additional Paid-in Capital [Member] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Lease Agreement 10770 Wateridge Circle, San Diego, California 92121 [Member] 10770 Wateridge Circle, San Diego, California 92121 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 Purchases of investments Payments to Acquire Debt Securities, Available-for-sale Number of milestones achieved during period Revenue Recognition, Milestone Method, Number Of Milestones Achieved During Period Revenue Recognition, Milestone Method, Number Of Milestones Achieved During Period Collaborative Arrangement and Arrangement Other than Collaborative [Domain] Collaborative Arrangement and Arrangement Other than Collaborative [Domain] Schedule of Time-based Restricted Stock Units Activity Share-based Payment Arrangement, Restricted Stock Unit, Activity [Table Text Block] Restricted stock units expected to vest (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested and Expected to Vest, Outstanding, Number Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested and Expected to Vest, Outstanding, Number Other income, net Other Nonoperating Income (Expense) Phase 2 clinical trial initiation Phase 2 Clinical Trial Initiation [Member] Phase 2 Clinical Trial Initiation [Member] Revenue recognition multiple deliverable arrangements upfront fee receivable Revenue Recognition Multiple Deliverable Arrangements Upfront Fees Revenue Recognition Multiple Deliverable Arrangements Upfront Fees Purchases of property and equipment Payments to Acquire Property, Plant, and Equipment Maximum Maximum [Member] Share-based Payment Arrangement [Abstract] Share-based Payment Arrangement [Abstract] Schedule of Milestones Achieved Collaborative Arrangement and Arrangement Other than Collaborative [Table Text Block] Schedule of Accrued Expenses Schedule of Accrued Liabilities [Table Text Block] Award Type [Axis] Award Type [Axis] Granted (in usd per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price CASH FLOWS FROM FINANCING ACTIVITIES: Net Cash Provided by (Used in) Financing Activities [Abstract] Aggregate intrinsic value, options outstanding Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value Schedule of Future Minimum Annual Obligations Lessee, Operating Lease, Liability, Maturity [Table Text Block] Total stockholders’ equity Stockholders' Equity, Beginning Balance Stockholders' Equity, Ending Balance Stockholders' Equity Attributable to Parent Balance Sheet Related Disclosures [Abstract] Balance Sheet Related Disclosures [Abstract] Common stock, shares issued (in shares) Common Stock, Shares, Issued Preferred stock, shares issued (in shares) Preferred Stock, Shares Issued City Area Code City Area Code Accounts payable and other liabilities Increase (Decrease) in Accounts Payable and Accrued Liabilities Aggregate intrinsic value, options exercisable Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value Entity Address, City or Town Entity Address, City or Town Issuance of common stock from exercises of options and employee stock purchase plan Stock Issued During Period, Value, Options and Employee Stock Purchase Plan Stock Issued During Period, Value, Options and Employee Stock Purchase Plan Stockholders’ equity: Stockholders' Equity Attributable to Parent [Abstract] Commercial and corporate obligations Commercial And Corporate Obligations [Member] Commercial And Corporate Obligations [Member] Operating lease liability, net of current portion Operating Lease, Liability, Noncurrent Measurement Frequency [Domain] Measurement Frequency [Domain] Anti-PD-1 (JEMPERLI/Dostarlimab) AnaptysBio-generated Anti-PD-1 (JEMPERLI/Dostarlimab) [Member] AnaptysBio-generated Anti-PD-1 (JEMPERLI/Dostarlimab) 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 Accumulated deficit Retained Earnings (Accumulated Deficit) Revenue from Contract with Customer, Product and Service [Extensible Enumeration] Revenue from Contract with Customer, Product and Service [Extensible Enumeration] Award expiration period (in years) Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period RSUs Restricted Stock Units (RSUs) [Member] Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Entity Filer Category Entity Filer Category Accrued research, development and manufacturing expenses Accrued Research And Development Expenses, Current Accrued Research And Development Expenses, Current Risk-free interest rate Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate Non-cash interest expense recognized Noncash Interest Expense Recognized Noncash Interest Expense Recognized First BLA approval - second indication First Biologics License Application Approval - Second Indication [Member] First Biologics License Application Approval - Second Indication US Treasury Securities US Treasury Securities [Member] Income Statement [Abstract] Income Statement [Abstract] Entity Registrant Name Entity Registrant Name Phase 3 clinical trial initiation - first indication Phase 3 Clinical Trial Initiation - First Indication [Member] Phase 3 Clinical Trial Initiation - First Indication Milestone payments, contingent upon preclinical and clinical trial events (up to) Total Contractual Milestones Remaining Revenue Recognition, Milestone Method, Contingent Upon Pre Clinical, Regulatory And Commercial Events Revenue Recognition, Milestone Method, Contingent Upon Pre Clinical, Regulatory And Commercial Events Royalties agreement, maximum annual royalty payout capacity Advance Future Royalties, Annual Sales Threshold Advance Future Royalties, Annual Sales Threshold Aggregate intrinsic value, expected to vest Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value Amendment Flag Amendment Flag Equity Components [Axis] Equity Components [Axis] Entity Tax Identification Number Entity Tax Identification Number Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Antidilutive Securities [Axis] Antidilutive Securities [Axis] Document Fiscal Period Focus Document Fiscal Period Focus Total current assets Assets, Current Total minimum payments required Lessee, Operating Lease, Liability, to be Paid Cancelled (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Schedule of Stock by Class [Table] Schedule of Stock by Class [Table] 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] Royalty payments to Sagard Advance Future Royalties Payments Advance Future Royalties Payments Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Interim President and Chief Executive Officer Interim President And Chief Executive Officer [Member] Interim President And Chief Executive Officer Security deposit Security Deposit Aggregate intrinsic value, beginning balance Aggregate intrinsic value, ending balance Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Nonvested Unrecognized compensation cost Share-based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount Product and Service [Axis] Product and Service [Axis] Property, Plant and Equipment, Type [Domain] Long-Lived Tangible Asset [Domain] 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] Preferred stock, par value (in dollars per share) Preferred Stock, Par or Stated Value Per Share CEO Chief Executive Officer [Member] Weighted average grant date fair value per share (in usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value Equity Component [Domain] Equity Component [Domain] Restricted stock units (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number Royalty percent on net sales (as a percent) Net Sales Royalty, Percent Net Sales Royalty, Percent 2023 Lessee, Operating Lease, Liability, to be Paid, Year One Non-cash interest expense for the sale of future royalties Non-cash interest expense for the sale of future royalties Noncash Advance Future Royalties, Interest Expense Noncash Advance Future Royalties, Interest Expense Statement [Line Items] Statement [Line Items] Weighted-Average Exercise Price per Share Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Long-term investments Debt Securities, Available-for-sale, Noncurrent Revenue Recognition [Abstract] Revenue Recognition [Abstract] Schedule of Non-cash Stock-based Compensation Expense Share-based Payment Arrangement, Cost by Plan [Table Text Block] Available-for-sale securities, debt securities Total Fair Value Debt Securities, Available-for-sale Counterparty Name [Domain] Counterparty Name [Domain] 2026 Lessee, Operating Lease, Liability, to be Paid, Year Four Significant Other Observable Inputs (Level 2) Fair Value, Inputs, Level 2 [Member] Property, Plant and Equipment, Type [Axis] Long-Lived Tangible Asset [Axis] Pre clinical and Development Pre Clinical and Development [Member] Pre Clinical and Development Fair Value Debt Securities, Available-for-sale, Unrealized Loss Position Investments at fair value Cash And Cash Equivalents And Restricted Cash, Fair Value Disclosure Cash And Cash Equivalents And Restricted Cash, Fair Value Disclosure Amortized Cost Debt Securities, Available-for-sale, Amortized Cost Use of Estimates Use of Estimates, Policy [Policy Text Block] Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross Title of 12(b) Security Title of 12(b) Security Issuance of common stock from exercises of options and employee stock purchase plan (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options And Employee Stock Purchase Plan Share-based Compensation Arrangement by Share-based Payment Award, Options And Employee Stock Purchase Plan Proceeds from issuance of common stock Proceeds from Issuance of Common Stock Total assets Assets Advance Future Royalties, Payment [Axis] Advance Future Royalties, Payment [Axis] Advance Future Royalties, Payment Directors Director [Member] Plan Name [Domain] Plan Name [Domain] Common stock, shares authorized (in shares) Common Stock, Shares Authorized Phase 3 clinical trial initiation - second indication Phase 3 clinical Trial Initiation - Second Indication [Member] Phase 3 clinical Trial Initiation - Second Indication [Member] Title of Individual [Axis] Title of Individual [Axis] Document Type Document Type Product and Service [Domain] Product and Service [Domain] Research and development Research and Development Expense Balance Sheet Accounts and Supplemental Disclosures Supplemental Balance Sheet Disclosures [Text Block] Lease termination term (in years) Lessee, Operating Lease, Lease Not yet Commenced, Expiration Period Lessee, Operating Lease, Lease Not yet Commenced, Expiration Period Advance Future Royalties, Payment [Domain] Advance Future Royalties, Payment [Domain] Advance Future Royalties, Payment [Domain] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Measurement Frequency [Axis] Measurement Frequency [Axis] Net cash used in operating activities Net Cash Provided by (Used in) Operating Activities Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Schedule of Costs in Cash Flow Statement Lease, Cost [Table Text Block] Increase in annual rent (as a percent) Annual Rent Increase, Percent Annual Rent Increase, Percent Basic (in shares) Weighted Average Number of Shares Outstanding, Basic Diluted (in usd per share) Earnings Per Share, Diluted Amortization of right-of-use assets – operating Operating Lease, Right-of-Use Asset, Amortization Expense Subsequent Event Subsequent Events [Text Block] 2017 Equity Incentive Plan Equity Incentive Plan, 2017 [Member] Equity Incentive Plan, 2017 [Member] Liability related to sale of future royalties Advance Future Royalties, Liability, Noncurrent Advance Future Royalties, Liability, Noncurrent Comprehensive loss Comprehensive Income (Loss), Net of Tax, Attributable to Parent Accretion/amortization of investments, net Unrealized Gain (Loss) on Investments Net cash provided by financing activities Net Cash Provided by (Used in) Financing Activities 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 Amendment Collaboration and Exclusive License Agreement [Member] Collaboration and Exclusive License Agreement Award vesting period (in years) Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Liabilities Related To Sale Of Future Royalties [Roll Forward] Liabilities Related To Sale Of Future Royalties [Roll Forward] Liabilities Related To Sale Of Future Royalties Fair Value Measurements and Available for Sale Investments Fair Value Disclosures [Text Block] Accounts payable Accounts Payable, Current Depreciation and amortization Depreciation, Depletion and Amortization 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] Filing of the first MAA - first indication Filing of MMA - First Indication [Member] Filing of MMA - First Indication Accumulated Other Comprehensive Loss AOCI Attributable to Parent [Member] 2017 Employee Stock Purchase Plan Employee Stock Purchase Plan, 2017 [Member] Employee Stock Purchase Plan, 2017 [Member] Common stock, shares outstanding (in shares) Common Stock, Shares, Outstanding Financial Instruments [Domain] Financial Instruments [Domain] Document Period End Date Document Period End Date Filing of the first BLA - first indication Filing of Biologics License Application - First Indication [Member] Filing of Biologics License Application - First Indication Entity Central Index Key Entity Central Index Key Noncash advance future royalties revenue Noncash Advance Future Royalties Revenue Noncash Advance Future Royalties Revenue Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Unrealized loss on available for sale securities OCI, Debt Securities, Available-for-Sale, Gain (Loss), after Adjustment and Tax Shares Subject to Options Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Lease renewal term (in years) Lessee, Operating Lease, Lease Not yet Commenced, Renewal Term Schedule of Property and Equipment, net Property, Plant and Equipment [Table Text Block] Income Statement Location [Domain] Income Statement Location [Domain] Debt Securities, Available-for-sale [Table] Debt Securities, Available-for-sale [Table] Non-cash investing and financing activities: Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Property and equipment, net Total property and equipment, net Property, Plant and Equipment, Net Total operating expenses Operating Expenses Royalty Agreement, Up To $1. 0 billion Royalty Agreement, Up To $1. 0 billion [Member] Royalty Agreement, Up To $1. 0 billion Trading Symbol Trading Symbol Collaborative Research And Development Agreement Collaborative Arrangement [Member] Property and equipment, gross Property, Plant and Equipment, Gross Gross Unrealized Losses Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss At any time after 2027 Third Installment [Member] Third Installment Liability related to sale of future royalties - beginning balance Liability related to sale of future royalties - ending balance Advance Future Royalties, Liabilities Advance Future Royalties, Liabilities Stock options outstanding, beginning balance (in usd per share) Stock options outstanding, ending balance (in usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Milestones achieved, amount Revenue Recognition, Milestone Method, Milestones Achieved During, Amount Revenue Recognition, Milestone Method, Milestones Achieved, Amount Stock based compensation expense Share-based Payment Arrangement, Expense Upfront license fee received Revenue Recognition, Multiple-deliverable Arrangements, Upfront Fee Received Revenue Recognition, Multiple-deliverable Arrangements, Upfront Fee Received 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 Entity Current Reporting Status Entity Current Reporting Status Net loss per common share: Earnings Per Share, Basic and Diluted [Abstract] Weighted average grant date fair value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Effective interest rate (as a percent) Advance Future Royalties, Interest Rate, Effective Percentage Advance Future Royalties, Interest Rate, Effective Percentage Issuance costs related to the sale of future royalties Issuance costs related to the sale of future royalties Advance Future Royalties, Issuance Costs Advance Future Royalties, Issuance Costs Counterparty Name [Axis] Counterparty Name [Axis] Cash, cash equivalents and restricted cash, beginning of period Cash, cash equivalents and restricted cash, end of period Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Current assets: Assets, Current [Abstract] Common stock, shares reserved for issuance (in shares) Common Stock, Capital Shares Reserved for Future Issuance Unrealized losses on available-for-sale Debt Securities, Available-for-sale, Unrealized Loss Entity Address, Postal Zip Code Entity Address, Postal Zip Code Shares issued under employee stock plans (in shares) Exercises (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Diluted (in shares) Weighted Average Number of Shares Outstanding, Diluted During 2027 Second Installment [Member] Second Installment Comprehensive loss, net Other Comprehensive Income (Loss), Net of Tax Recurring Fair Value, Recurring [Member] Amounts accrued for issuance costs related to the sale of future royalties Noncash Advance Future Royalties, Issuance Costs, Incurred but Not yet Paid Noncash Advance Future Royalties, Issuance Costs, Incurred but Not yet Paid Schedule of Activity Related to Stock Option Awards Share-based Payment Arrangement, Option, Activity [Table Text Block] Stockholders' Equity Stockholders' Equity Note Disclosure [Text Block] Anti-TIM-3 (GSK4069889A/Cobolimab) AnaptysBio Generated Anti-TIM-3 (GSK4069889A/Cobolimab) [Member] AnaptysBio Generated Anti-TIM-3 (GSK4069889A/Cobolimab) Former CEO Former Chief Executive Officer [Member] Former Chief Executive Officer 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] Commercial Commercial [Member] Commercial Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Other income (expense), net: Nonoperating Income (Expense) [Abstract] Name of Property [Axis] Name of Property [Axis] Class of Stock [Line Items] Class of Stock [Line Items] Entity Address, Address Line One Entity Address, Address Line One Net cash (used in) provided by investing activities Net Cash Provided by (Used in) Investing Activities Entity Address, Address Line Two Entity Address, Address Line Two Changes in operating assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Less: accumulated depreciation and amortization Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment CASH FLOWS FROM OPERATING ACTIVITIES: Net Cash Provided by (Used in) Operating Activities [Abstract] Vested (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value General and administrative General and Administrative Expense [Member] Basis of Consolidation Consolidation, Policy [Policy Text Block] Entity Shell Company Entity Shell Company Expected term (in years) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term Total current liabilities Liabilities, Current ESPP Employee Stock [Member] Stock-based compensation APIC, Share-based Payment Arrangement, Option, Increase for Cost Recognition Amortization of issuance costs Amortization Of Advance Future Royalties Issuance Costs Amortization Of Advance Future Royalties Issuance Costs Money Market Funds Money Market Funds [Member] Current Fiscal Year End Date Current Fiscal Year End Date Mutual Funds Mutual Fund [Member] Statement [Table] Statement [Table] Statistical Measurement [Axis] Statistical Measurement [Axis] Gross Unrealized Losses Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Name of Property [Domain] Name of Property [Domain] Description of the Business Nature of Operations [Text Block] 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] Operating lease cost Operating Lease, Cost Cash and Cash Equivalents [Axis] Cash and Cash Equivalents [Axis] Gross Unrealized Losses Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Initiated in vivo toxicology studies using good laboratory practices (GLPs) In Vivo Toxicology Studies [Member] In Vivo Toxicology Studies [Member] Collaboration Revenue [Member] Collaboration Revenue