Fair Value Measurements - Schedule of Assets and Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Assets:
Total	$ 1,408,315	$ 1,028,439
U.S. government treasuries
Assets:
Short-term marketable securities, fair value	829,409	869,172
Long-term marketable securities, fair value	475,196
U.S. government agency securities
Assets:
Short-term marketable securities, fair value		7,086
Corporate debt securities
Assets:
Short-term marketable securities, fair value	1,079
Long-term marketable securities, fair value	15,527
Commercial paper
Assets:
Short-term marketable securities, fair value	45,807	31,147
Money market funds
Assets:
Cash equivalents	41,297	121,034
Level 1
Assets:
Total	1,345,902	990,206
Level 1 | U.S. government treasuries
Assets:
Short-term marketable securities, fair value	829,409	869,172
Long-term marketable securities, fair value	475,196
Level 1 | U.S. government agency securities
Assets:
Short-term marketable securities, fair value		0
Level 1 | Corporate debt securities
Assets:
Short-term marketable securities, fair value	0
Long-term marketable securities, fair value	0
Level 1 | Commercial paper
Assets:
Short-term marketable securities, fair value	0	0
Level 1 | Money market funds
Assets:
Cash equivalents	41,297	121,034
Level 2
Assets:
Total	62,413	38,233
Level 2 | U.S. government treasuries
Assets:
Short-term marketable securities, fair value	0	0
Long-term marketable securities, fair value	0
Level 2 | U.S. government agency securities
Assets:
Short-term marketable securities, fair value		7,086
Level 2 | Corporate debt securities
Assets:
Short-term marketable securities, fair value	1,079
Long-term marketable securities, fair value	15,527
Level 2 | Commercial paper
Assets:
Short-term marketable securities, fair value	45,807	31,147
Level 2 | Money market funds
Assets:
Cash equivalents	0	0
Level 3
Assets:
Total	0	0
Level 3 | U.S. government treasuries
Assets:
Short-term marketable securities, fair value	0	0
Long-term marketable securities, fair value	0
Level 3 | U.S. government agency securities
Assets:
Short-term marketable securities, fair value		0
Level 3 | Corporate debt securities
Assets:
Short-term marketable securities, fair value	0
Long-term marketable securities, fair value	0
Level 3 | Commercial paper
Assets:
Short-term marketable securities, fair value	0	0
Level 3 | Money market funds
Assets:
Cash equivalents	$ 0	$ 0