Fair Value Measurements - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended		9 Months Ended
	Jul. 07, 2023	Jun. 22, 2023	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Series A Non Voting Convertible Preferred Stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Proceeds from issuance of stock, settled liability	$ 189,700				$ 0	$ 197,364
Parapyre Option Obligation
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Percentage of annual equity grant of options			1.00%		1.00%
CVR liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Changes in the fair value of the CVR liability					$ 19,630
Change in fair value of forward contract liability					19,630	(1,300)
Forward contract liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of forward contract liability		$ 106,200
Change in fair value of forward contract liability			$ 0	$ 25,360	$ 0	$ 83,530
Spyre Therapeutics, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset acquisition, stockholder payment period		3 years
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]
Number of shares transferred as equity interest in asset acquisition (in shares)		364,887
Outstanding Parapyre warrants
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Warrants to purchase shares (in shares)							684,407
Exercise price per warrant (in dollars per share)							$ 21.52