Fair Value Measurements - Narrative (Details) - USD ($)			6 Months Ended	12 Months Ended
	Jul. 07, 2023	Jun. 22, 2023	Dec. 31, 2023	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of liability				$ 26,680,000	$ 61,700,000
Forward Contract Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of liability		$ 106,200,000
Change in fair value of derivative liability				0	0	$ 83,530,000
Increase in fair value of derivative			$ 83,500,000
CVR Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Change in fair value of derivative liability				(29,769,000)	$ 20,430,000	18,986,000
Increase in fair value of derivative				$ (29,769,000)
Series A Non-Voting Convertible Preferred Stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Issuance of Series A non-voting convertible preferred stock	$ 189,700,000					$ 189,741,000
Spyre Therapeutics, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset acquisition, cash payment, threshold period		1 year
Spyre Therapeutics, Inc. | Series A Non-Voting Convertible Preferred Stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Shares transferred as equity interest in asset acquisition (in shares)		364,887