Condensed Consolidated Statements of Changes in Convertible Preferred Stock and Stockholders' (Deficit) Equity - USD ($)	Total	Series A Non Voting Convertible Preferred Stock	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2021		0
Beginning balance at Dec. 31, 2021		$ 0
Ending balance (in shares) at Mar. 31, 2022		0
Beginning balance at Mar. 31, 2022		$ 0
Beginning balances (in shares) at Dec. 31, 2021			1,974,000
Beginning balance at Dec. 31, 2021	$ 83,941,000		$ 5,000	$ 425,765,000	$ (20,000)	$ (341,809,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock in connection with employee stock purchase plan (in shares)			3,000
Issuance of common stock in connection with employee stock purchase plan	184,000			184,000
Stock-based compensation expense	2,101,000			2,101,000
Foreign currency translation adjustment	(13,000)				(13,000)
Unrealized gain (loss) on marketable securities	(120,000)				(120,000)
Net loss	(24,436,000)					(24,436,000)
Ending balance (in shares) at Mar. 31, 2022			1,977,000
Ending balance at Mar. 31, 2022	61,657,000		$ 5,000	428,050,000	(153,000)	(366,245,000)
Beginning balance (in shares) at Dec. 31, 2021		0
Beginning balance at Dec. 31, 2021		$ 0
Ending balance (in shares) at Sep. 30, 2022		0
Beginning balance at Sep. 30, 2022		$ 0
Beginning balances (in shares) at Dec. 31, 2021			1,974,000
Beginning balance at Dec. 31, 2021	83,941,000		$ 5,000	425,765,000	(20,000)	(341,809,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Foreign currency translation adjustment	(87,000)
Unrealized gain (loss) on marketable securities	(77,000)
Net loss	(64,993,000)
Ending balance (in shares) at Sep. 30, 2022			2,460,000
Ending balance at Sep. 30, 2022	67,555,000		$ 6,000	474,535,000	(184,000)	(406,802,000)
Beginning balance (in shares) at Mar. 31, 2022		0
Beginning balance at Mar. 31, 2022		$ 0
Ending balance (in shares) at Jun. 30, 2022		0
Beginning balance at Jun. 30, 2022		$ 0
Beginning balances (in shares) at Mar. 31, 2022			1,977,000
Beginning balance at Mar. 31, 2022	61,657,000		$ 5,000	428,050,000	(153,000)	(366,245,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock in connection with exercise of pre-funded warrants (in shares)			40,000
Issuance of common stock and pre-funded warrants in connection with registered direct offering, net of offering costs (in shares)			430,000
Issuance of common stock and pre-funded warrants in connection with registered direct offering, net of offering costs	42,873,000		$ 1,000	42,872,000
Stock-based compensation expense	2,017,000			2,017,000
Foreign currency translation adjustment	(36,000)				(36,000)
Unrealized gain (loss) on marketable securities	(31,000)				(31,000)
Net loss	(22,323,000)					(22,323,000)
Ending balance (in shares) at Jun. 30, 2022			2,447,000
Ending balance at Jun. 30, 2022	84,157,000		$ 6,000	472,939,000	(220,000)	(388,568,000)
Ending balance (in shares) at Sep. 30, 2022		0
Beginning balance at Sep. 30, 2022		$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock and pre-funded warrants in connection with registered direct offering, net of offering costs (in shares)			10,000
Issuance of common stock in connection with exercise of pre-funded warrants	(8,000)			(8,000)
Issuance of common stock in connection with employee stock purchase plan (in shares)			3,000
Issuance of common stock in connection with employee stock purchase plan	38,000			38,000
Stock-based compensation expense	1,566,000			1,566,000
Foreign currency translation adjustment	(38,000)				(38,000)
Unrealized gain (loss) on marketable securities	74,000				74,000
Net loss	(18,234,000)					(18,234,000)
Ending balance (in shares) at Sep. 30, 2022			2,460,000
Ending balance at Sep. 30, 2022	67,555,000		$ 6,000	474,535,000	(184,000)	(406,802,000)
Beginning balance (in shares) at Dec. 31, 2022		0
Beginning balance at Dec. 31, 2022		$ 0
Ending balance (in shares) at Mar. 31, 2023		0
Beginning balance at Mar. 31, 2023		$ 0
Beginning balances (in shares) at Dec. 31, 2022			2,614,000
Beginning balance at Dec. 31, 2022	50,305,000		$ 6,000	475,971,000	(48,000)	(425,624,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock in connection with employee stock purchase plan (in shares)			2,000
Issuance of common stock in connection with employee stock purchase plan	18,000			18,000
Stock-based compensation expense	1,709,000			1,709,000
Foreign currency translation adjustment	10,000				10,000
Unrealized gain (loss) on marketable securities	32,000				32,000
Net loss	(18,422,000)					(18,422,000)
Ending balance (in shares) at Mar. 31, 2023			2,616,000
Ending balance at Mar. 31, 2023	33,652,000		$ 6,000	477,698,000	(6,000)	(444,046,000)
Beginning balance (in shares) at Dec. 31, 2022		0
Beginning balance at Dec. 31, 2022		$ 0
Ending balance (in shares) at Sep. 30, 2023		1,086,339
Beginning balance at Sep. 30, 2023		$ 387,105,000
Beginning balances (in shares) at Dec. 31, 2022			2,614,000
Beginning balance at Dec. 31, 2022	50,305,000		$ 6,000	475,971,000	(48,000)	(425,624,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Foreign currency translation adjustment	(1,000)
Unrealized gain (loss) on marketable securities	(83,000)
Net loss	(275,610,000)
Ending balance (in shares) at Sep. 30, 2023			4,049,000
Ending balance at Sep. 30, 2023	(245,402,000)		$ 7,000	455,957,000	(132,000)	(701,234,000)
Beginning balance (in shares) at Mar. 31, 2023		0
Beginning balance at Mar. 31, 2023		$ 0
Series A Non-Voting Convertible Preferred Stock
Issuance of Series A non-voting convertible preferred stock (in shares)		721,000
Issuance of Series A non-voting convertible preferred stock		$ 197,323,000
Ending balance (in shares) at Jun. 30, 2023		721,000
Beginning balance at Jun. 30, 2023		$ 197,323,000
Beginning balances (in shares) at Mar. 31, 2023			2,616,000
Beginning balance at Mar. 31, 2023	33,652,000		$ 6,000	477,698,000	(6,000)	(444,046,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock forward in connection with the asset acquisition of Spyre	3,768,000			3,768,000
Issuance of common stock in connection with exercise of pre-funded warrants (in shares)			624,000
CVR distribution to common stockholders	(29,500,000)			(29,500,000)
Stock-based compensation expense	1,775,000			1,775,000
Foreign currency translation adjustment	18,000				18,000
Unrealized gain (loss) on marketable securities	(1,000)				(1,000)
Net loss	(217,081,000)					(217,081,000)
Ending balance (in shares) at Jun. 30, 2023			3,240,000
Ending balance at Jun. 30, 2023	(207,369,000)		$ 6,000	453,741,000	11,000	(661,127,000)
Series A Non-Voting Convertible Preferred Stock
Issuance of Series A non-voting convertible preferred stock (in shares)		365,000
Issuance of Series A non-voting convertible preferred stock		$ 189,741,000
Settlement of financing costs in connection with private placement of Series A non-voting convertible preferred stock		$ 41,000
Ending balance (in shares) at Sep. 30, 2023		1,086,339
Beginning balance at Sep. 30, 2023		$ 387,105,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock in connection with exercise of stock options and employee stock purchase plan	105,000			105,000
Issuance of common stock in connection with the asset acquisition of Spyre and settlement of related forward contract (in shares)			518,000
Issuance of common stock in connection with the asset acquisition of Spyre and settlement of related forward contract	0		$ 1,000	(1,000)
Issuance of common stock in connection with exercise of pre-funded warrants (in shares)			281,000
Issuance of common stock in connection with exercise of stock options and employee stock purchase plan (in shares)			10,000
Stock-based compensation expense	2,112,000			2,112,000
Foreign currency translation adjustment	(29,000)				(29,000)
Unrealized gain (loss) on marketable securities	(114,000)				(114,000)
Net loss	(40,107,000)					(40,107,000)
Ending balance (in shares) at Sep. 30, 2023			4,049,000
Ending balance at Sep. 30, 2023	$ (245,402,000)		$ 7,000	$ 455,957,000	$ (132,000)	$ (701,234,000)