Related Party Transactions - Additional Information (Details) - USD ($)		1 Months Ended	3 Months Ended			9 Months Ended
		Jun. 30, 2024	Sep. 30, 2024	Jun. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Related Party Transaction [Line Items]
Research and development expense	[1]		$ 15,543,000		$ 7,580,000	$ 43,736,000	$ 16,200,000
General and administrative expense	[2]		6,097,000		$ 1,984,000	15,798,000	5,185,000
Accounts payable	[3]		1,323,000			1,323,000		$ 2,502,000
Accrued expenses	[3]		5,056,000			5,056,000		5,631,000
Common Stock
Related Party Transaction [Line Items]
Additional share purchased				9,200,000
IPO | Common Stock
Related Party Transaction [Line Items]
Additional share purchased		9,200,000
Janssen
Related Party Transaction [Line Items]
Costs incurred						69,000	200,000
Accounts payable			0			0		0
Accrued expenses			0			0		0
Third Rock
Related Party Transaction [Line Items]
Costs incurred						100,000	1,000,000
Research and development expense						0	300,000
General and administrative expense						100,000	$ 700,000
Accounts payable			0			0		200,000
Accrued expenses			$ 0			$ 0		$ 0

[1] Includes related party amounts of zero for each of the three months ended September 30, 2024 and 2023, and less than $0.1 million and $0.5 million for the nine months ended September 30, 2024 and 2023, respectively (see Note 10).

[2] Includes related party amounts of zero and $0.2 million for the three months ended September 30, 2024 and 2023, respectively and $0.1 million and $0.7 million for the nine months ended September 30, 2024 and 2023, respectively (see Note 10).

[3] Includes related party amounts of zero and $0.2 million (accounts payable) and less than $0.1 million and zero (accrued expenses) as of September 30, 2024 and December 31, 2023, respectively (see Notes 5 and 10).