Fair Value Measurements - Recurring Fair Value Measurements (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Assets
Short-term investments	$ 217,569	$ 268,724
Fair Value, Measurements, Recurring
Assets
Total assets measured at fair value	988,276	1,127,309
Level 1 \| Fair Value, Measurements, Recurring
Assets
Total assets measured at fair value	889,813	1,098,841
Level 2 \| Fair Value, Measurements, Recurring
Assets
Total assets measured at fair value	98,463	28,468
Level 3 \| Fair Value, Measurements, Recurring
Assets
Total assets measured at fair value	0	0
Money market funds \| Fair Value, Measurements, Recurring
Assets
Cash equivalents	483,640	627,983
Money market funds \| Level 1 \| Fair Value, Measurements, Recurring
Assets
Cash equivalents	483,640	627,983
Money market funds \| Level 2 \| Fair Value, Measurements, Recurring
Assets
Cash equivalents	0	0
Money market funds \| Level 3 \| Fair Value, Measurements, Recurring
Assets
Cash equivalents	0	0
U.S. treasury bills \| Fair Value, Measurements, Recurring
Assets
Cash equivalents	199,150	230,602
U.S. treasury bills \| Level 1 \| Fair Value, Measurements, Recurring
Assets
Cash equivalents	199,150	230,602
U.S. treasury bills \| Level 2 \| Fair Value, Measurements, Recurring
Assets
Cash equivalents	0	0
U.S. treasury bills \| Level 3 \| Fair Value, Measurements, Recurring
Assets
Cash equivalents	0	0
Commercial paper \| Fair Value, Measurements, Recurring
Assets
Cash equivalents	16,603
Commercial paper \| Level 1 \| Fair Value, Measurements, Recurring
Assets
Cash equivalents	0
Commercial paper \| Level 2 \| Fair Value, Measurements, Recurring
Assets
Cash equivalents	16,603
Commercial paper \| Level 3 \| Fair Value, Measurements, Recurring
Assets
Cash equivalents	0
Corporate debt securities \| Fair Value, Measurements, Recurring
Assets
Cash equivalents	49,311
Short-term investments		2,975
Corporate debt securities \| Level 1 \| Fair Value, Measurements, Recurring
Assets
Cash equivalents	0
Short-term investments		0
Corporate debt securities \| Level 2 \| Fair Value, Measurements, Recurring
Assets
Cash equivalents	49,311
Short-term investments		2,975
Corporate debt securities \| Level 3 \| Fair Value, Measurements, Recurring
Assets
Cash equivalents	0
Short-term investments		0
Certificate of deposits \| Fair Value, Measurements, Recurring
Assets
Cash equivalents	22,003
Certificate of deposits \| Level 1 \| Fair Value, Measurements, Recurring
Assets
Cash equivalents	0
Certificate of deposits \| Level 2 \| Fair Value, Measurements, Recurring
Assets
Cash equivalents	22,003
Certificate of deposits \| Level 3 \| Fair Value, Measurements, Recurring
Assets
Cash equivalents	0
U.S. treasury securities \| Fair Value, Measurements, Recurring
Assets
Short-term investments	207,023	240,256
U.S. treasury securities \| Level 1 \| Fair Value, Measurements, Recurring
Assets
Short-term investments	207,023	240,256
U.S. treasury securities \| Level 2 \| Fair Value, Measurements, Recurring
Assets
Short-term investments	0	0
U.S. treasury securities \| Level 3 \| Fair Value, Measurements, Recurring
Assets
Short-term investments	0	0
U.S. agency securities \| Fair Value, Measurements, Recurring
Assets
Short-term investments		14,993
U.S. agency securities \| Level 1 \| Fair Value, Measurements, Recurring
Assets
Short-term investments		0
U.S. agency securities \| Level 2 \| Fair Value, Measurements, Recurring
Assets
Short-term investments		14,993
U.S. agency securities \| Level 3 \| Fair Value, Measurements, Recurring
Assets
Short-term investments		0
Asset-backed securities \| Fair Value, Measurements, Recurring
Assets
Short-term investments	10,546	10,500
Asset-backed securities \| Level 1 \| Fair Value, Measurements, Recurring
Assets
Short-term investments	0	0
Asset-backed securities \| Level 2 \| Fair Value, Measurements, Recurring
Assets
Short-term investments	10,546	10,500
Asset-backed securities \| Level 3 \| Fair Value, Measurements, Recurring
Assets
Short-term investments	$ 0	$ 0