Fair Value Measurements - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Feb. 28, 2021	Dec. 31, 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Write off of accrued interest receivable	$ 0	$ 0
Humabs
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Estimated fair value of contingent consideration	63,300,000			$ 29,200,000
TomegaVax
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Estimated fair value of contingent consideration	$ 7,100,000			6,800,000
TomegaVax | TomegaVax Letter Agreement
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Estimated fair value of contingent consideration			$ 10,000,000.0
Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities contractual term	1 year
Prepaid Expenses and Other Current Assets
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Accrued interest receivable excluded from fair value and amortized cost basis of available for sale securities	$ 700,000			$ 800,000
Contingent Consideration Liability | TomegaVax | TomegaVax Letter Agreement
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Estimated fair value of contingent consideration			$ 10,000,000.0