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Fair Value Measurements - Additional Information (Details) - USD ($) | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2023 | Mar. 31, 2022 | Dec. 31, 2022
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |
Estimated fair value of equity securities | $ 25,028,000 |  | $ 32,020,000
Unrealized (loss) gain on equity securities | (6,992,000) | $ 563,000 |
Vaxcyte, Inc. | Vaxcyte Common Stock |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |
Estimated fair value of equity securities | 25,000,000.0 |  | 32,000,000.0
Unrealized (loss) gain on equity securities | $ (7,000,000.0) |  | $ 600,000
Vaxcyte, Inc. | Equity Securities | Vaxcyte Common Stock |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |
Number of shares held | 667,780 |  | 667,780
Fair Value Measurements Recurring |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |
Securities held | $ 275,125,000 |  | $ 330,430,000
Fair Value Measurements Recurring | Level 3 |  |  |
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] |  |  |
Securities held | $ 0 |  | $ 0

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