Agenus Transaction	6 Months Ended
Agenus Transaction	Jun. 30, 2024
Business Combination, Asset Acquisition, and Joint Venture Formation [Abstract]
Agenus Transaction	Agenus Transaction On May 29, 2024, we closed the transactions pursuant to the $75 million purchase and sale agreement (the “Agenus Agreement”), dated May 6, 2024, among us and Agenus Inc., Agenus Royalty Fund, LLC, and Agenus Holdings 2024, LLC (collectively, “Agenus”). Under the terms of the Agenus Agreement, we received (i) 18.75% of the licensed royalties and 31.875% of the future licensed milestones paid to Agenus on six-partnered oncology programs, including BMS-986442 (Bristol Myers Squibb), AGEN2373 (Gilead Sciences), INCAGN2385 and INCAGN2390 (Incyte), MK-4830 (Merck), and UGN-301 (UroGen Pharma) (collectively referred as "Agenus Partnered Programs"), and (ii) a synthetic 2.625% royalty on future global net sales of Agenus’ novel immuno-oncology botensilimab in combination with balstilimab (“BOT/BAL”) program, collectively subject to certain events which may adjust the royalty and milestone percentages paid to us. In addition, we received the option to commit an additional $25 million in the same assets on a pro rata basis which expires on June 30, 2025 ("Upsize Option"). We have also agreed to allow Agenus to raise up to an additional $100 million bringing the total syndicated purchase price up to an aggregate of $200 million. As part of the Agenus Agreement, Agenus will grant us security over certain assets related to the programs included in the Agenus Agreement, subject to certain customary exceptions. In connection with entry into the Agenus Agreement, Agenus issued us a 5-year warrant (“Agenus Warrant”) to purchase 867,052 shares of its common stock, at an exercise price equal to $17.30. We accounted for all Agenus Partnered Programs, Agenus Warrant and Upsize Option as derivative assets. Upsize Option was presented within current derivative assets line (as it expires on June 30, 2025), and the other derivatives were presented in noncurrent derivative assets line in our condensed consolidated balance sheet. Agenus Partnered Programs are recognized as derivative assets under ASC 815, Derivatives and Hedging, as they have different underlyings (development milestones, commercial milestones, and royalties). The commercial milestones and royalties are dependent on the development milestones and the commercial milestone and royalties underlyings are not determined to be predominate. The derivative assets were recorded at fair value as of May 29, 2024, and will be marketed to fair value at each reporting period going forward. The fair value of Agenus Partnered Programs derivative assets was determined as a present value of expected future cash flows adjusted for the level of risk appropriate for a respective program stage. The fair value of Agenus Warrant was determined using a Black-Scholes model using the following assumptions: expected term of 4 years, volatility of 84%, risk-free rate of 4.7%, Agenus Stock price at May 29, 2024 of $15.03. The fair value of the Upsize Option was determined using the binomial option pricing model under which we assessed and considered the possible upwards and downwards scenarios through the expiration date of the Upsize Option. We accounted for the acquired BOT/BAL rights as a financial royalty asset which is currently put under the non-accrual method as management can not reliably estimate future cash flows from this program. The amount of BOT/BAL financial royalty asset was determined as a residual value from $75 million investment amount, less fair value of all acquired derivative assets as of May 29, 2024. Uncertainty relating to development-stage product candidates requires management to make estimates and assumptions that affect the reported amounts of assets. There can be no assurance that our assumptions around the likelihood of a development-stage product candidate’s approval or achieving significant sales will prove correct, that regulatory authorities will approve such development-stage product candidates, that such development-stage product candidates will be brought to market timely or at all, or that such products will achieve commercial success or result in royalties consistent with our estimates.