Segment Information - Schedule of Operating Segments (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2025	Mar. 31, 2024
Operating expenses:
External research and development costs	[1]	$ 46,387	$ 28,716
General and administrative operations		16,709	9,465
Depreciation expense		207	29
Provision for income taxes		83	0
Consolidated net loss		(55,339)	(32,094)
Reportable Segment
Operating expenses:
Research and development personnel-related (excluding equity-based compensation)	[2]	15,296	5,903
External-discovery related costs and other	[2]	4,127	2,071
General and administrative personnel-related (excluding equity-based compensation)	[2]	5,707	3,533
General and administrative operations	[2],[3]	5,105	3,676
Equity-based compensation	[2]	11,126	4,186
Depreciation expense	[2]	207	29
Interest income		(7,840)	(6,087)
Provision for income taxes		83	0
Consolidated net loss		55,339	32,094
Reportable Segment | APG777
Operating expenses:
External research and development costs	[2]	14,571	5,955
Reportable Segment | APG990 / APG777 + APG990
Operating expenses:
External research and development costs	[2]	3,213	5,210
Reportable Segment | APG333 / APG777 + APG333
Operating expenses:
External research and development costs	[2]	2,434	3,659
Reportable Segment | APG808
Operating expenses:
External research and development costs	[2]	$ 1,310	$ 3,959

[1] Includes related-party amounts of $32 for the three months ended March 31, 2025, and $6,457 for the three months ended March 31, 2024.

[2] The significant expense categories and amounts align with the segment-level information that is regularly provided to the CODM

[3] General and administrative operations are comprised of finance, investor relations, business development, human resources, legal, facilities & IT, and certain overhead expenses