License Agreements - Agenus (Details) - USD ($) $ in Thousands |
3 Months Ended | 111 Months Ended | |||||
|---|---|---|---|---|---|---|---|
Mar. 31, 2024 |
Mar. 31, 2023 |
Mar. 31, 2024 |
Dec. 31, 2023 |
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| License Agreements | |||||||
| Fair market long term investments | $ 287,663 | $ 287,663 | $ 187,716 | [1] | |||
| Unrealized gain (loss) on long term investments | $ 99,947 | $ (5,318) | |||||
| Agenus | |||||||
| License Agreements | |||||||
| Common stock held from investment (in shares) | 12,100,000 | 12,100,000 | |||||
| Fair market long term investments | $ 7,000 | $ 7,000 | $ 10,000 | ||||
| Unrealized gain (loss) on long term investments | (3,000) | $ (10,600) | |||||
| Development, Regulatory and Commercialization Milestones | Agenus | |||||||
| License Agreements | |||||||
| Milestone payment made under license agreement | 30,000 | ||||||
| Additional milestone payments under the license agreement | $ 500,000 | $ 500,000 | |||||
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