Fair Value of Financial Instruments - Valuation of financial instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Fair Value of Financial Instruments
Cash equivalents	$ 57,144	$ 314,218
Short-term investments	257,157	692,024
Total	314,301	1,006,242
Money market funds
Fair Value of Financial Instruments
Cash equivalents	57,144	310,969
Corporate debt securities
Fair Value of Financial Instruments
Cash equivalents		3,249
Short-term investments	166,868	501,014
Government debt securities
Fair Value of Financial Instruments
Short-term investments	90,289	191,010
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value of Financial Instruments
Cash equivalents	57,144	310,969
Total	57,144	310,969
Quoted Prices in Active Markets for Identical Assets (Level 1) | Money market funds
Fair Value of Financial Instruments
Cash equivalents	57,144	310,969
Significant Other Observable Inputs (Level 2)
Fair Value of Financial Instruments
Cash equivalents		3,249
Short-term investments	257,157	692,024
Total	257,157	695,273
Significant Other Observable Inputs (Level 2) | Corporate debt securities
Fair Value of Financial Instruments
Cash equivalents		3,249
Short-term investments	166,868	501,014
Significant Other Observable Inputs (Level 2) | Government debt securities
Fair Value of Financial Instruments
Short-term investments	$ 90,289	$ 191,010