Income Taxes - Summary of Net Deferred Income Tax Asset (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Deferred tax assets:
Capitalized research and development	$ 65,606	$ 41,901
Net operating losses	32,148	14,443
Equity-based compensation	21,035	16,960
Research and development credits	6,970	3,155
Accrued expenses	2,699	1,836
Basis difference on gain on sale of Cullinan Pearl	1,700	1,700
Licenses	694	7,189
Lease liability	590	985
Capitalized organizational and start-up expenses	101	116
Gross deferred tax assets	131,543	88,285
Valuation allowance	(130,939)	(87,371)	$ (46,766)
Net deferred tax asset	604	914
Deferred tax liability
ROU asset	457	697
Depreciation and amortization	147	217
Net deferred tax asset	$ 0	$ 0