CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Cash flows from operating activities:
Net loss	$ (112,961)	$ (5,005)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	578	1,293
Noncash lease expense	2,065	1,306
Loss from equity method investment	25,881	5,488
Stock-based compensation expense	7,324	13,054
Accretion of discount on short-term investments	(2,948)	(1,947)
Non-cash gain on lease termination	(8,866)	0
(Gain) loss on disposal of property and equipment	(94)	49
Gain on sale of business	0	(131,249)
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	4,988	840
Accounts payable	2,090	(981)
Accrued expenses and other liabilities	(11,686)	7,418
Deferred revenue	(1,156)	(3,208)
Operating lease liabilities	(1,445)	(719)
Net cash used in operating activities	(96,230)	(113,661)
Cash flows from investing activities:
Purchases of short-term investments	(73,240)	(157,460)
Maturities of short-term investments	174,240	65,461
Proceeds from sale of business	0	130,000
Proceeds from sale of property and equipment	554	0
Purchases of property and equipment	(228)	(1,285)
Net cash provided by investing activities	101,326	36,716
Cash flows from financing activities:
Proceeds from issuance of common stock pursuant to employee stock purchase plan	168	595
Proceeds from issuance of common stock from option exercises	16	1
Net cash provided by financing activities	184	596
Net change in cash, cash equivalents and restricted cash	5,280	(76,349)
Cash, cash equivalents and restricted cash, beginning of period	33,986	110,335
Cash, cash equivalents and restricted cash, end of period	39,266	33,986
Supplemental disclosures of noncash investing and financing activities:
Lease Liability Settled Through Termination Of Lease	28,338	0
Lease liability obtained in exchange for right-of-use asset	1,625	0
Cash paid for income taxes	0	720
Unrealized gain (loss) on available for sale securities, net	399	(397)
Property and equipment additions included in accrued expenses and other liabilities	$ 0	$ 8