The Company and Basis of Presentation - Additional Information (Details) $ / shares in Units, $ in Thousands			1 Months Ended	6 Months Ended
	Jun. 26, 2023 USD ($) shares	Jun. 22, 2023 $ / shares shares	Apr. 30, 2023 Employee	Jun. 30, 2023 USD ($) Segment $ / shares	Dec. 31, 2022 USD ($) $ / shares
Company and Basis of Presentation [Line Items]
Number of operating segments | Segment				1
Preferred stock, par value | $ / shares				$ 0.0001	$ 0.0001
Accumulated deficit | $				$ (661,127)	$ (425,624)
Cash and cash equivalents | $				$ 235,358	$ 34,863
Percentage of existing headcount reduction			83.00%
Number of employees retained | Employee			10
Asset Acquisition
Company and Basis of Presentation [Line Items]
Fixed exchange ratio		13.73622
Spyre 2023 Equity Incentive Plan | Asset Acquisition
Company and Basis of Presentation [Line Items]
Outstanding and unexercised stock options | shares		68,365
Series A Preferred Stock
Company and Basis of Presentation [Line Items]
Preferred stock, par value | $ / shares		$ 0.0001
Conversion basis		1,000
Series A Preferred Stock | Asset Acquisition
Company and Basis of Presentation [Line Items]
Asset acquisition consideration transferred equity interest issued, shares | shares		364,887
Preferred stock, par value | $ / shares		$ 0.0001
Conversion basis		1,000
Private Placement | Series A Preferred Stock
Company and Basis of Presentation [Line Items]
Number of shares | shares	721,452
Aggregate purchase price of shares | $	$ 210,000
Placement agent and other offering expenses | $	$ 12,700
Common Stock | Asset Acquisition
Company and Basis of Presentation [Line Items]
Asset acquisition consideration transferred equity interest issued, shares | shares		12,945,385