Related Party Transactions - Narrative (Details)			3 Months Ended		9 Months Ended
		Nov. 22, 2023 installment $ / shares shares	Sep. 30, 2026 USD ($) seat shares	Sep. 30, 2025 USD ($) shares	Sep. 30, 2026 USD ($) seat shares	Sep. 30, 2025 USD ($) shares	Dec. 31, 2025 USD ($)
Related Party Transaction [Line Items]
Research and development	[1]		$ 89,169,000	$ 45,247,000	$ 215,083,000	$ 127,015,000
Options granted to purchase (in shares) | shares			80,385	213,900	2,849,446	2,539,617
Stock-based compensation expense			$ 14,167,000	$ 9,566,000	$ 40,485,000	$ 27,803,000
Related Party
Related Party Transaction [Line Items]
Research and development			100,000	7,000,000.0	3,200,000	9,600,000
Total related party accounts payable			100,000		100,000		$ 0
Paragon Agreement | Related Party
Related Party Transaction [Line Items]
Amount of related party transaction			$ 0	0	$ 100,000	200,000
Appoint Of Board Members
Related Party Transaction [Line Items]
Number of board seats held by related party | seat			1		1
Other Paragon Reimbursable Expenses | Related Party
Related Party Transaction [Line Items]
Research and development			$ 0	0	$ 100,000	100,000
Consulting Agreement | Related Party
Related Party Transaction [Line Items]
Options granted to purchase (in shares) | shares		477,000
Exercise price (in dollars per share) | $ / shares		$ 10.39
Number of monthly installments | installment		36
Stock-based compensation expense			$ 300,000	$ 300,000	$ 800,000	$ 800,000
Consulting Agreement | Related Party | Share-Based Payment Arrangement, Tranche One
Related Party Transaction [Line Items]
Vesting percentage		25.00%
Vest period grant date (in years)		1 year
Paragon Therapeutics Inc | Maximum | Paragon Agreement | Related Party
Related Party Transaction [Line Items]
Percentage of ownership by noncontrolling owner			5.00%		5.00%
Fairmount Funds Management LLC | Minimum | Paragon Agreement | Related Party
Related Party Transaction [Line Items]
Percentage of ownership by noncontrolling owner			5.00%		5.00%
Percentage of ownership held in third party			5.00%		5.00%

[1] Includes related party expenses of $0.1 million and $7.0 million for the three months ended September 30, 2026 and 2025, respectively. Includes related party expenses of $3.2 million and $9.6 million for the nine months ended September 30, 2026 and 2025, respectively.