Available for Sale Debt Securities	3 Months Ended
Available for Sale Debt Securities	Mar. 31, 2026
Investments, Debt and Equity Securities [Abstract]
Available for Sale Debt Securities	Available for Sale Debt Securities Funding Arrangements with Cytokinetics In May 2024, we expanded our funding collaboration with Cytokinetics, Incorporated (“Cytokinetics”). As part of the expanded funding collaboration, we provided funding of $100 million for Cytokinetics’ Phase 3 clinical trial of omecamtiv mecarbil (“Cytokinetics Development Funding”) and amended the funding agreement that we entered into with Cytokinetics in 2022 to provide two additional funding tranches (as amended, “Cytokinetics Commercial Launch Funding”). Following the amendment in May 2024, the Cytokinetics Commercial Launch Funding is comprised of seven tranches with total funding of up to $525 million. Our return on the Cytokinetics Development Funding depends on the outcome of omecamtiv mecarbil’s Phase 3 clinical trial and approval by the U.S. Food and Drug Administration (the “FDA”). If omecamtiv mecarbil’s Phase 3 clinical trial is successful and approval by the FDA is received within a specific timeframe, we will receive a return of $100 million and the greater of an incremental 2.0% royalty on annual net sales of omecamtiv mecarbil or quarterly fixed payments for 18 quarters and an incremental 2.0% royalty thereafter. If FDA approval is not received within a specific timeframe, we will receive a return of 2.4 times the Cytokinetics Development Funding over 18 quarters. If the Phase 3 clinical trial is not successful within a specific timeframe, we will receive a return of 2.3 times the Cytokinetics Development Funding over 22 quarters. Out of the seven tranches of the Cytokinetics Commercial Launch Funding, we have funded a total of $275 million under tranches one, four, five and six as of March 31, 2026, including the required minimum draw in April 2025. Tranches two and three are no longer available because the related regulatory milestones were not met. In the fourth quarter of 2025, the contingency for tranche seven was met and up to $175 million became available for Cytokinetics to draw (“Cytokinetics Funding Commitments”) through the fourth quarter of 2026. For tranches one, four, five, six and seven, we expect a return of 1.9 times the amount drawn over 34 consecutive quarterly payments beginning on the last business day of the seventh quarter following the quarter each tranche was funded. We began receiving quarterly repayments on tranche one and tranche six in the fourth quarter of 2023 and first quarter of 2026, respectively. We elected the fair value option to account for the Cytokinetics Development Funding and the Cytokinetics Commercial Launch Funding (collectively the “Cytokinetics Funding Arrangements”) as it most accurately reflects the nature of the funding arrangements. The funded Cytokinetics Funding Arrangements are recorded within Available for sale debt securities on the condensed consolidated balance sheets. The Cytokinetics Funding Commitments are recognized at fair value within Other liabilities on the condensed consolidated balance sheets. The changes in the fair value of the funded Cytokinetics Funding Arrangements and Cytokinetics Funding Commitments are recorded within Losses on available for sale debt securities in the condensed consolidated statements of operations. Further, as part of the expanded funding collaboration in May 2024, we purchased Cytokinetics common stock and provided funding for clinical trials of CK-586 in exchange for a royalty. Lastly, the funding collaboration also included the restructuring of our royalty on Myqorzo, formerly known as aficamten.