Segment Reporting - Schedule of Segment Operating Expenses Including Segment Expenses, and Net Loss (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023
Operating expenses:
Direct research and development		$ 126,172	$ 78,225
Total operating expenses		167,170	102,012
Loss from operations		(167,170)	(102,012)
Other income (expense):
Interest income		20,714	7,979
Interest expense		(7,626)	(3,786)
Loss before provision for income taxes		(152,147)	(95,989)
Provision for income taxes		1	1
Segment and consolidated net loss		152,148	95,990
Operating Segments [Member]
Operating expenses:
Payroll and related		48,843	28,878
Depreciation and amortization		105	22
Other segment items*	[1]	35,190	18,452
Total operating expenses		167,170	102,012
Loss from operations		(167,170)	(102,012)
Other income (expense):
Interest income		20,714	7,979
Interest expense		(7,626)	(3,786)
Other segment items**	[2]	1,935	1,830
Loss before provision for income taxes		(152,147)	(95,989)
Provision for income taxes		(1)	(1)
Segment and consolidated net loss		(152,148)	(95,990)
Other Significant Items:
Expenditures for additions to long-lived assets		(972)	(63)
Operating Segments [Member] | Clinical Trials [Member]
Operating expenses:
Direct research and development		32,279	19,611
Operating Segments [Member] | Contract Manufacturing [Member]
Operating expenses:
Direct research and development		$ 50,753	$ 35,049

[1] *Other segment items included in total operating expenses primarily consist of consulting and contractors, professional services, equipment and software, travel and entertainment, facilities, medical affairs, commercial planning, and corporate communications.

[2] **Other segment items included in loss before provision for income taxes consist of currency exchange gains and losses and other income/expense.