Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Fair Value of Financial Instruments
Marketable securities, available-for-sale	$ 792,997	$ 695,885
U.S. government agency securities
Fair Value of Financial Instruments
Marketable securities, available-for-sale	133,488	169,803
U.S. Treasury obligations
Fair Value of Financial Instruments
Marketable securities, available-for-sale	659,509	526,082
Recurring
Fair Value of Financial Instruments
Total	850,150	751,297
Recurring | U.S. government agency securities
Fair Value of Financial Instruments
Marketable securities, available-for-sale	133,488	169,803
Recurring | U.S. Treasury obligations
Fair Value of Financial Instruments
Marketable securities, available-for-sale	659,509	526,082
Recurring | Money market funds
Fair Value of Financial Instruments
Cash equivalents	57,153	55,412
Recurring | Active Markets (Level 1)
Fair Value of Financial Instruments
Total	716,662	581,494
Recurring | Active Markets (Level 1) | U.S. Treasury obligations
Fair Value of Financial Instruments
Marketable securities, available-for-sale	659,509	526,082
Recurring | Active Markets (Level 1) | Money market funds
Fair Value of Financial Instruments
Cash equivalents	57,153	55,412
Recurring | Observable Inputs (Level 2)
Fair Value of Financial Instruments
Total	133,488	169,803
Recurring | Observable Inputs (Level 2) | U.S. government agency securities
Fair Value of Financial Instruments
Marketable securities, available-for-sale	$ 133,488	$ 169,803