Description of the Business	9 Months Ended
Description of the Business	Sep. 30, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of the Business	Description of the Business AnaptysBio, Inc. (“we,” “us,” “our,” or the “company”) was incorporated in the state of Delaware in November 2005. We are a clinical-stage biotechnology company focused on delivering innovative immunology therapeutics for autoimmune and inflammatory diseases. Our pipeline includes our lead program, rosnilimab, a selective and potent pathogenic T cell depleter, that completed a Phase 2b trial for the treatment of moderate-to-severe rheumatoid arthritis (“RA”) and is in a Phase 2 trial for the treatment of moderate-to-severe ulcerative colitis (“UC”). Our pipeline also includes ANB033, a CD122 antagonist, in a Phase 1b trial for celiac disease (“CeD”) and ANB101, a BDCA2 modulator, in a Phase 1a trial. Anaptys has also discovered and out-licensed in financial collaborations multiple therapeutic antibodies, including a PD-1 antagonist (Jemperli (dostarlimab-gxly) or “Jemperli”) to GSK and an IL-36R antagonist (imsidolimab) to Vanda Pharmaceuticals Inc. (“Vanda”). We currently recognize revenue from milestones and royalties achieved under our immuno-oncology collaboration with GSK and license and transition services revenue from our collaboration with Vanda. Since our inception, we have devoted our primary effort to research and development activities. Our financial support has been provided primarily from the sale of our common stock and royalty monetizations, as well as through funds received under our collaborative research and development agreements. Going forward, as we continue our expansion, we may seek additional financing and/or strategic investments. However, there can be no assurance that any additional financing or strategic investments will be available to us on acceptable terms, if at all. If events or circumstances occur such that we do not obtain additional funding, we will most likely be required to reduce our plans and/or certain discretionary spending, which could have a material adverse effect on our ability to achieve our intended business objectives. Our management believes our currently available resources will provide sufficient funds to enable us to meet our operating plans for at least the next 12 months from the issuance of our consolidated financial statements. The accompanying consolidated financial statements do not include any adjustments that might be necessary if we are unable to continue as a going concern. Intention to Separate Company In September 2025, we announced that our Board of Directors approved plans to explore separating our business into two independent, publicly traded companies. One company is expected to hold and continue to manage the Jemperli milestones and royalties from GSK and the milestones and royalties from Vanda with a focus on protecting and returning value of the royalties to its shareholders. The other company is expected to be a clinical-stage biotechnology company focused on the development and potential commercialization of innovative therapeutics for autoimmune and inflammatory diseases, including rosnilimab, ANB033 and ANB101. Upon completion of the separation, which is expected to be completed by year-end 2026, we intend to launch the biotechnology company with adequate capital to fund operations for at least two years. While the separation is anticipated to be a taxable event, we are focused on minimizing overall corporate and shareholder-level taxes across the entire transaction. Completion of the proposed separation is subject to final approval by our Board of Directors and other customary conditions, including the effectiveness of a registration statement with the Securities and Exchange Commission (the “SEC”).