Nature of business and future operations	3 Months Ended
Nature of business and future operations	Mar. 31, 2026
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of business and future operations	Nature of business and future operations Description of the Business Arbutus Biopharma Corporation (“Arbutus” or the “Company”) is a clinical-stage biopharmaceutical company focused on infectious disease. The Company is currently developing imdusiran (AB-729), its proprietary, GalNAc-conjugated, subcutaneously-delivered ribonucleic acid interference (RNAi) therapeutic, and AB-101, its proprietary oral PD-L1 inhibitor, for the treatment of chronic hepatitis B (cHBV). The Company continues to protect and defend its intellectual property, which is the subject of its ongoing lawsuit against Pfizer Inc. and BioNTech SE (collectively, Pfizer/BioNTech) for their use of the Company’s patented lipid nanoparticle (LNP) technology in their COVID-19 messenger ribonucleic acid interference (mRNA)-LNP vaccines. The court issued a claim construction ruling in September 2025, which construed the disputed claim terms in a manner the Company generally considers to be favorable. The parties are awaiting further scheduling in the litigation. On March 3, 2026, the Company, along with Genevant Sciences GmbH and, solely for specified purposes, its parent company Genevant Sciences Ltd. (collectively, Genevant), entered into a settlement agreement (the Moderna Settlement Agreement) with Moderna Inc. and ModernaTX, Inc. (together, Moderna) to resolve all patent infringement litigation and patent revocation proceedings involving Moderna and its affiliates pending in the United States and internationally (the Moderna LNP Litigation). Under the terms of the Moderna Settlement Agreement, Moderna will make an aggregate $950.0 million noncontingent lump sum payment (the Noncontingent Settlement Payment) to the Company and Genevant on or before July 8, 2026. In addition, Moderna is obligated to pay the Company and Genevant an additional aggregate contingent lump sum payment of $1.3 billion (the Contingent Settlement Payment) upon a ruling that is favorable to the Company and Genevant in a limited appeal related to 28 U.S.C. §1498 (§1498) that Moderna filed, as allowed under the Moderna Settlement Agreement (the Moderna §1498 Appeal). Under the Company’s license with Genevant, it is entitled to receive, after deduction of litigation costs, 20% of the Noncontingent Settlement Payment. The Company currently expects to receive an estimated $178.7 million of the Noncontingent Settlement Payment, which includes reimbursement of the Company’s litigation costs. In addition, as of March 31, 2026, the Company owned approximately 16% of the outstanding common equity of Genevant. Liquidity At March 31, 2026, the Company had an aggregate of $95.2 million in cash, cash equivalents and investments in marketable securities. The Company had no outstanding debt as of March 31, 2026. The Company believes it has sufficient cash resources to fund its operations for at least the next 12 months. The success of the Company’s operations is dependent on obtaining the necessary regulatory approvals to bring one or more of its product candidates to market and achieve profitability from ongoing operations. The Company’s development activities and the commercialization of its products are dependent on its ability to successfully complete these activities and to obtain adequate financing through a combination of financing activities and operations. It is not possible to predict either the outcome of the Company’s existing or future development programs or the Company’s ability to continue to fund these programs in the future.