Fair Value Measurements - Financial Assets Measured at Fair Value on a Recurring Basis by Level Within Fair Value Hierarchy (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and cash equivalents	$ 666,949	$ 848,631	$ 1,505,183
Amortized Cost	1,836,085	2,403,183
Gross Unrealized Holding Gains	20	0
Gross Unrealized Holding Losses	(2,215)	(8,396)
Aggregate Fair Value	1,847,421	2,426,679
Level 1 | Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	425,881	909,342
Cash and cash equivalents	425,881	909,342
Level 1 | Equity securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	13,531	31,892
Level 2 | U.S. government treasuries
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	1,284,324	1,493,841
Gross Unrealized Holding Gains	12	0
Gross Unrealized Holding Losses	(1,978)	(8,396)
Aggregate Fair Value	1,282,358	$ 1,485,445
Level 2 | U.S. government agency bonds and discount notes
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	125,880
Gross Unrealized Holding Gains	8
Gross Unrealized Holding Losses	(237)
Aggregate Fair Value	$ 125,651