Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss	$ (82,694)	$ (235,503)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	22,517	3,620
Acquired in-process research and development	0	130,486
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	(5,984)	(123)
Interest proceeds from maturities of zero coupon US Treasury Bills	124	0
Depreciation and amortization	0	744
Amortization of operating lease assets	0	220
Other	0	6
Changes in operating assets and liabilities:
Accounts payable	2,335	2,045
Accrued and other liabilities	(7,623)	(1,058)
Related party accounts payable	(12,906)	1,247
Prepaid expenses and other assets	(7,489)	3,368
Deferred revenue	0	575
Development receivables	0	(1,271)
Operating lease liabilities	0	(298)
Net cash used in operating activities	(90,790)	(34,277)
CASH FLOWS FROM INVESTING ACTIVITIES
Proceeds from maturities and sales of marketable securities	105,626	21,000
Purchases of marketable securities	(331,107)	0
Cash assumed from asset acquisition of Spyre	0	3,035
Proceeds from sale of property and equipment	0	475
Net cash (used in) and provided by investing activities	(225,481)	24,510
CASH FLOWS FROM FINANCING ACTIVITIES
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	4,885	18
Principal payments on finance lease obligation	0	(16)
Net cash provided by financing activities	172,525	210,002
Effect of exchange rate on cash, cash equivalents, and restricted cash	(4)	24
NET (DECREASE) INCREASE IN CASH, CASH EQUIVALENTS, AND RESTRICTED CASH	(143,750)	200,259
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH
Beginning of period	189,215	36,416
End of period	45,465	236,675
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
Unpaid direct transaction costs related to the asset acquisition of Spyre	0	2,067
Reconciliation of Cash, Cash Equivalents, and Restricted Cash Reported in the Statement of Financial Position
Cash and cash equivalents	45,144	235,358
Restricted cash	321	1,317
Total cash, cash equivalents, and restricted cash shown in the statement of cash flows	45,465	236,675
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	169,070	0
Supplemental Disclosure of Non-Cash Investing and Financing Information:
Unpaid amounts related to issuance of Series B non-voting convertible preferred stock in connection with private placement	220	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	210,000
Supplemental Disclosure of Non-Cash Investing and Financing Information:
Unpaid amounts related to issuance of Series A non-voting convertible preferred stock in connection with private placement	0	12,677
CVR liability
Adjustments to reconcile net loss to net cash used in operating activities:
Change in fair value of derivative liability	930	0
Forward contract liability
Adjustments to reconcile net loss to net cash used in operating activities:
Change in fair value of derivative liability	$ 0	$ 58,170