Fair Value Measurements - Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Financial assets:
Total financial assets	$ 609,238	$ 694,495
Financial liabilities:
Success payment liabilities	3,753	4,356
Total financial liabilities	3,753	4,356
U.S. Treasury securities
Financial assets:
Marketable securities	291,289	271,799
U.S. government agency securities
Financial assets:
Marketable securities	94,511	134,045
Corporate debt securities
Financial assets:
Marketable securities	106,468	220,681
Money market funds
Financial assets:
Money market funds	116,970	67,970
Level 1
Financial assets:
Total financial assets	116,970	67,970
Financial liabilities:
Success payment liabilities	0	0
Total financial liabilities	0	0
Level 1 | U.S. Treasury securities
Financial assets:
Marketable securities	0	0
Level 1 | U.S. government agency securities
Financial assets:
Marketable securities	0	0
Level 1 | Corporate debt securities
Financial assets:
Marketable securities	0	0
Level 1 | Money market funds
Financial assets:
Money market funds	116,970	67,970
Level 2
Financial assets:
Total financial assets	492,268	626,525
Financial liabilities:
Success payment liabilities	0	0
Total financial liabilities	0	0
Level 2 | U.S. Treasury securities
Financial assets:
Marketable securities	291,289	271,799
Level 2 | U.S. government agency securities
Financial assets:
Marketable securities	94,511	134,045
Level 2 | Corporate debt securities
Financial assets:
Marketable securities	106,468	220,681
Level 2 | Money market funds
Financial assets:
Money market funds	0	0
Level 3
Financial assets:
Total financial assets	0	0
Financial liabilities:
Success payment liabilities	3,753	4,356
Total financial liabilities	3,753	4,356
Level 3 | U.S. Treasury securities
Financial assets:
Marketable securities	0	0
Level 3 | U.S. government agency securities
Financial assets:
Marketable securities	0	0
Level 3 | Corporate debt securities
Financial assets:
Marketable securities	0	0
Level 3 | Money market funds
Financial assets:
Money market funds	$ 0	$ 0