Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss	$ (151,722)	$ (275,610)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	35,617	8,405
Acquired in-process research and development	0	130,188
Gain on sale of in-process research and development asset	0	(14,609)
Lease ROU asset and leasehold improvement impairment loss	0	2,580
Loss on disposal of long-lived assets	0	915
Net accretion of discount on marketable securities	(8,985)	(612)
Interest proceeds from maturities of zero coupon US Treasury Bills	581	0
Depreciation and amortization	0	744
Amortization of operating lease assets	0	220
Other	0	18
Changes in operating assets and liabilities:
Accounts payable	4,268	1,001
Accrued and other liabilities	(257)	(4,000)
Related party accounts payable	(15,138)	(2,115)
Prepaid expenses and other assets	(4,205)	3,310
Deferred revenue	0	575
Development receivables	0	212
Operating lease liabilities	0	(2,326)
Net cash used in operating activities	(120,211)	(68,874)
CASH FLOWS FROM INVESTING ACTIVITIES
Proceeds from maturities and sales of marketable securities	183,419	21,000
Purchases of marketable securities	(366,160)	(112,631)
Cash assumed from asset acquisition of Spyre	0	3,035
Proceeds from sale of in-process research & development asset	0	15,000
Proceeds from sale of property and equipment	0	475
Net cash used in investing activities	(182,741)	(73,121)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from issuance of common stock in connection with at-the-market offerings, net of issuance costs	11,760	0
Payment of deferred offering costs in connection with shelf registration	(78)
Payments related to contingent value rights liability	(1,430)	0
Proceeds from employee stock option exercises, employee stock plan purchases, and exercise of prefunded warrants	6,203	123
Principal payments on finance lease obligation	0	(16)
Net cash provided by financing activities	185,305	197,471
Effect of exchange rate on cash, cash equivalents, and restricted cash	12	7
NET (DECREASE) INCREASE IN CASH, CASH EQUIVALENTS, AND RESTRICTED CASH	(117,635)	55,483
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH
Beginning of period	189,215	36,416
End of period	71,580	91,899
Supplemental Disclosure of Non-Cash Investing and Financing Information:
Exchange of Series A non-voting convertible preferred stock for common stock	38,502	0
Conversion of Series B non-voting convertible preferred stock into common stock	244,010	0
Allocation of deferred offering costs against proceeds of issuance of common stock	10	0
Reconciliation of Cash, Cash Equivalents, and Restricted Cash Reported in the Statement of Financial Position
Cash and cash equivalents	71,580	90,592
Restricted cash	0	1,307
Total cash, cash equivalents, and restricted cash shown in the statement of cash flows	71,580	91,899
Series B Non Voting Convertible Preferred Stock
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from issuance of Series A/B non-voting convertible preferred stock in connection with private placement	168,850	0
Series A Non Voting Convertible Preferred Stock
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from issuance of Series A/B non-voting convertible preferred stock in connection with private placement	0	197,364
Supplemental Disclosure of Non-Cash Investing and Financing Information:
Unpaid amounts related to issuance of common stock in connection with at-the-market offerings, net of offering costs	329	0
CVR liability
Adjustments to reconcile net loss to net cash used in operating activities:
Change in fair value of derivative liability	19,630	(1,300)
Forward contract liability
Adjustments to reconcile net loss to net cash used in operating activities:
Change in fair value of derivative liability	$ 0	$ 83,530