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Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) $ in Thousands | 1 Months Ended | 3 Months Ended | 6 Months Ended | 12 Months Ended |
--- | --- | --- | --- | --- | ---
Jan. 31, 2010 cvr | Jun. 30, 2024 USD ($) | Jun. 30, 2024 USD ($) | Dec. 31, 2023 USD ($) | Sep. 18, 2023 contract
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |
Derivative Asset Statement Of Financial Position Extensible Enumeration Not Disclosed Flag |  |  | Derivative assets(2) | Derivative assets(2) |
Number of CVR Series | cvr | 4 |  |  |  |
Agenus Partnered Program |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |
Percentage of milestones (as a percent) |  |  |  |  | 50.00%
Agenus Partnered Program | Primordial Genetics |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |
Number of contracts | contract |  |  |  |  | 2
Transferred over Time | Phase 3 clinical trial |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |
Gross contract asset |  | $ 10,000 | $ 10,000 |  |
Minimum | Agenus Partnered Program | Discount Rate |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |
Discount rate (as a percent) |  | 0.13 | 0.13 |  |
Maximum | Agenus Partnered Program | Discount Rate |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |
Discount rate (as a percent) |  | 0.25 | 0.25 |  |
Maximum | Transferred over Time | Development, regulatory, & commercial milestones and tiered royalties |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |
Investments |  | $ 375,000 | $ 375,000 |  |
Metabasis |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |
Number of CVRs issued per acquiree share | cvr | 4 |  |  |  |
Number of CVRs issued from each CVR series | cvr | 1 |  |  |  |
Frequency of cash payments to CVR holders | 6 months |  |  |  |
Increase of mark-to-market adjustment of CVR liability |  | 1,100 | 1,100 |  |
Recurring |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |
Investment in Viking common stock |  | 53,010 | 53,010 | $ 32,185 |
Derivative asset |  | 54,646 | 54,646 | 3,531 |
Total assets |  | 263,439 | 263,439 | 150,886 |
Total liabilities |  | 4,198 | 4,198 | 3,198 |
Recurring | Short-term investments, excluding Viking |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |
Investments, fair value |  | 155,783 | 155,783 | 115,170 |
Recurring | Contingent liabilities | CyDex |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |
Contingent liabilities |  | 264 | 264 | 320 |
Recurring | Contingent liabilities | Metabasis |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |
Contingent liabilities |  | 3,934 | 3,934 | 2,878 |
Recurring | Level 1 |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |
Investment in Viking common stock |  | 53,010 | 53,010 | 32,185 |
Derivative asset |  | 0 | 0 | 0 |
Total assets |  | 63,117 | 63,117 | 39,476 |
Total liabilities |  | 0 | 0 | 0 |
Recurring | Level 1 | Short-term investments, excluding Viking |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |
Investments, fair value |  | 10,107 | 10,107 | 7,291 |
Recurring | Level 1 | Contingent liabilities | CyDex |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |
Contingent liabilities |  | 0 | 0 | 0 |
Recurring | Level 1 | Contingent liabilities | Metabasis |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |
Contingent liabilities |  | 0 | 0 | 0 |
Recurring | Level 2 |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |
Investment in Viking common stock |  | 0 | 0 | 0 |
Derivative asset |  | 0 | 0 | 0 |
Total assets |  | 145,676 | 145,676 | 107,879 |
Total liabilities |  | 3,934 | 3,934 | 2,878 |
Recurring | Level 2 | Short-term investments, excluding Viking |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |
Investments, fair value |  | 145,676 | 145,676 | 107,879 |
Recurring | Level 2 | Contingent liabilities | CyDex |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |
Contingent liabilities |  | 0 | 0 | 0 |
Recurring | Level 2 | Contingent liabilities | Metabasis |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |
Contingent liabilities |  | 3,934 | 3,934 | 2,878 |
Recurring | Level 3 |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |
Investment in Viking common stock |  | 0 | 0 | 0 |
Derivative asset |  | 54,646 | 54,646 | 3,531 |
Total assets |  | 54,646 | 54,646 | 3,531 |
Total liabilities |  | 264 | 264 | 320 |
Recurring | Level 3 | Short-term investments, excluding Viking |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |
Investments, fair value |  | 0 | 0 | 0 |
Recurring | Level 3 | Contingent liabilities | CyDex |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |
Contingent liabilities |  | 264 | 264 | 320 |
Recurring | Level 3 | Contingent liabilities | Metabasis |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |
Contingent liabilities |  | $ 0 | $ 0 | $ 0 |

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