CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOW - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Cash flows from operating activities:
Net loss	$ (59,863)	$ (59,054)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,482	1,552
Amortization and premium of marketable securities, net	(2,416)	1,308
Loss (gain) on sale or disposal of assets	0	57
Gain on fair value remeasurement of contingent consideration	0	(6,862)
Stock-based compensation expense	9,557	6,607
Changes in operating assets and liabilities:
Accounts and other receivables	229	75
Other assets	(3)
Prepaid and other current assets	(61)	(8,485)
Accounts payable and accrued expenses	(2,970)	(862)
Litigation settlement payable	0	15,000
Other liabilities	(1,720)	3,886
Net cash used in operating activities	(55,765)	(46,778)
Cash flows from investing activities:
Sales and maturities of marketable securities	210,150	106,756
Purchases of marketable securities	(155,422)	(69,847)
Acquisition of property and equipment	(995)	(1,248)
Net cash provided by investing activities	53,733	35,661
Cash flows from financing activities:
Proceeds from issuance of stock from employee benefit plans	827	375
Net cash provided by financing activities	827	375
Net decrease in cash and cash equivalents	(1,205)	(10,742)
Cash and cash equivalents at beginning of period	29,429	39,143
Cash and cash equivalents at end of period	28,224	28,401
Non-cash investing activities
Accrued construction in progress	$ 46	$ 54