Nature of Operations	6 Months Ended
Jun. 30, 2026
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Operations	Nature of Operations Zymeworks Inc. together with its subsidiaries (collectively the “Company” or “Zymeworks”) is a global biotechnology company managing a portfolio of licensed healthcare assets and developing a diverse pipeline of novel, multifunctional biotherapeutics to improve the standard of care for difficult-to-treat diseases, including cancer, inflammation, and autoimmune disease. Zymeworks BC Inc. (“Zymeworks BC”), (previously known as “Zymeworks Inc.”) was incorporated on September 8, 2003 under the laws of the Canada Business Corporations Act. On October 22, 2003, the Company was registered as an extra-provincial company under the Company Act (British Columbia). On May 2, 2017, the Company continued under the Business Corporations Act (British Columbia). Since its inception, the Company has devoted substantially all of its resources to research and development activities, including developing its therapeutic platforms and identifying and developing potential product candidates by undertaking preclinical studies and clinical trials. The Company supports these activities through general and administrative support, as well as by raising capital, conducting business planning and protecting its intellectual property. Proposed Theravance Acquisition On June 28, 2026, Zymeworks Inc. (“Parent”) entered into an Agreement and Plan of Merger (the “Merger Agreement”) with Zymeworks Merger Sub 1, a wholly owned subsidiary of Parent (“Merger Sub”), and Theravance Biopharma, Inc. (“Theravance”), providing for the merger of Merger Sub with and into Theravance (the “Merger”), with Theravance surviving the Merger as a wholly owned subsidiary of the Company (the “Surviving Company”). Pursuant to the Merger Agreement, each outstanding Theravance ordinary share will be converted into the right to receive $17.00 in cash and one contingent value right (“CVR”), subject to the terms and conditions of the Merger Agreement and the related CVR agreement. The CVR will entitle holders to receive certain contingent payments tied to specified future ampreloxetine-related proceeds and milestones. Consummation of the Merger is subject to customary closing conditions, including, without limitation, the expiration or termination of any waiting periods under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, applicable to the Merger (“HSR Act Clearance”) and the approval of the Merger Agreement, the Merger and the other transactions contemplated thereby by the affirmative vote of holders of Ordinary Shares representing at least two-thirds of the Ordinary Shares (the “Theravance Requisite Vote”) present and voting in person or by proxy as a single class at an extraordinary general meeting of Theravance for the purpose of approving the Merger Agreement, the Merger and the other transactions contemplated thereby. The parties expect the Merger and the other transactions contemplated by the Merger Agreement to close in the second half of 2026. The Company expects to finance the Merger with a combination of cash on hand and new debt financing. In connection with, and concurrently with entry into the Merger Agreement, Parent entered into a debt commitment letter dated June 28, 2026 (the “Debt Commitment Letter”) with OCM IP Healthcare Portfolio LP (“OMERS Life Sciences”), pursuant to which OMERS Life Sciences has agreed to purchase senior secured notes to be issued by certain newly formed special purpose vehicles in an aggregate principal amount of $350,000 on the terms and subject to the conditions set forth in the Debt Commitment Letter for the purposes of financing the transactions contemplated by the Merger Agreement. The obligations of OMERS Life Sciences to provide the debt financing under the Debt Commitment Letter are subject to conditions customary for a transaction of this type. The Company has not completed its assessment of the accounting impacts of the proposed acquisition, including any preliminary allocation of consideration or valuation of acquired assets and assumed liabilities, as the transaction has not yet been completed.

Zymeworks Inc. together with its subsidiaries (collectively the “Company” or “Zymeworks”) is a global biotechnology company managing a portfolio of licensed healthcare assets and developing a diverse pipeline of novel, multifunctional biotherapeutics to improve the standard of care for difficult-to-treat diseases, including cancer, inflammation, and autoimmune disease. Zymeworks BC Inc. (“Zymeworks BC”), (previously known as “Zymeworks Inc.”) was incorporated on September 8, 2003 under the laws of the Canada Business Corporations Act. On October 22, 2003, the Company was registered as an extra-provincial company under the Company Act (British Columbia). On May 2, 2017, the Company continued under the Business Corporations Act (British Columbia).

Since its inception, the Company has devoted substantially all of its resources to research and development activities, including developing its therapeutic platforms and identifying and developing potential product candidates by undertaking preclinical studies and clinical trials. The Company supports these activities through general and administrative support, as well as by raising capital, conducting business planning and protecting its intellectual property.

On June 28, 2026, Zymeworks Inc. (“Parent”) entered into an Agreement and Plan of Merger (the “Merger Agreement”) with Zymeworks Merger Sub 1, a wholly owned subsidiary of Parent (“Merger Sub”), and Theravance Biopharma, Inc. (“Theravance”), providing for the merger of Merger Sub with and into Theravance (the “Merger”), with Theravance surviving the Merger as a wholly owned subsidiary of the Company (the “Surviving Company”).

Pursuant to the Merger Agreement, each outstanding Theravance ordinary share will be converted into the right to receive $17.00 in cash and one contingent value right (“CVR”), subject to the terms and conditions of the Merger Agreement and the related CVR agreement. The CVR will entitle holders to receive certain contingent payments tied to specified future ampreloxetine-related proceeds and milestones.

Consummation of the Merger is subject to customary closing conditions, including, without limitation, the expiration or termination of any waiting periods under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, applicable to the Merger (“HSR Act Clearance”) and the approval of the Merger Agreement, the Merger and the other transactions contemplated thereby by the affirmative vote of holders of Ordinary Shares representing at least two-thirds of the Ordinary Shares (the “Theravance Requisite Vote”) present and voting in person or by proxy as a single class at an extraordinary general meeting of Theravance for the purpose of approving the Merger Agreement, the Merger and the other transactions contemplated thereby. The parties expect the Merger and the other transactions contemplated by the Merger Agreement to close in the second half of 2026.

The Company expects to finance the Merger with a combination of cash on hand and new debt financing. In connection with, and concurrently with entry into the Merger Agreement, Parent entered into a debt commitment letter dated June 28, 2026 (the “Debt Commitment Letter”) with OCM IP Healthcare Portfolio LP (“OMERS Life Sciences”), pursuant to which OMERS Life Sciences has agreed to purchase senior secured notes to be issued by certain newly formed special purpose vehicles in an aggregate principal amount of $350,000 on the terms and subject to the conditions set forth in the Debt Commitment Letter for the purposes of financing the transactions contemplated by the Merger Agreement. The obligations of OMERS Life Sciences to provide the debt financing under the Debt Commitment Letter are subject to conditions customary for a transaction of this type.

The Company has not completed its assessment of the accounting impacts of the proposed acquisition, including any preliminary allocation of consideration or valuation of acquired assets and assumed liabilities, as the transaction has not yet been completed.