Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements - Additional Information (Details)

v3.22.2.2
Fair Value Measurements - Additional Information (Details) - USD ($)
3 Months Ended 9 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2022
Sep. 30, 2021
Dec. 31, 2021
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]          
Estimated fair value of equity securities $ 36,909,000   $ 36,909,000   $ 37,181,000
Unrealized gain (loss) on equity securities 3,496,000 $ 4,483,000 323,000 $ (1,881,000)  
Realized gain (loss) on equity securities     30,000    
Vaxcyte, Inc. | Vaxcyte Common Stock          
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]          
Estimated fair value of equity securities 36,900,000   36,900,000   $ 37,200,000
Unrealized gain (loss) on equity securities $ 3,500,000 $ 4,500,000 $ 300,000 $ (1,900,000)  
Equity Securities | Vaxcyte, Inc. | Vaxcyte Common Stock          
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]          
Number of shares held 1,537,879   1,537,879   1,562,879
Shares of common stock 25,000 0 25,000 0  
Realized gain (loss) on equity securities $ 30,000,000 $ 0 $ 30,000,000 $ 0  
Fair Value Measurements Recurring          
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]          
Securities held 323,364,000   323,364,000   $ 265,750,000
Fair Value Measurements Recurring | Level 3          
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]          
Securities held $ 0   $ 0   $ 0