CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOW - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Cash flows from operating activities:
Net loss	$ (98,123)	$ (85,838)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	2,249	2,223
Amortization and premium of marketable securities, net	(4,043)	1,366
Loss on sale or disposal of assets		1
Gain on fair value remeasurement of contingent consideration	0	(6,862)
Stock-based compensation expense	16,678	11,103
Changes in operating assets and liabilities:
Accounts and other receivables	95	(17)
Prepaid and other current assets	1,757	(7,928)
Other assets	(3)
Accounts payable and accrued expenses	5,507	720
Other liabilities	1,125	3,262
Net cash used in operating activities	(74,758)	(81,970)
Cash flows from investing activities:
Sales and maturities of marketable securities	249,703	192,866
Purchases of marketable securities	(183,172)	(132,613)
Acquisition of property and equipment	(1,152)	(1,593)
Proceeds from sale or disposal of assets		69
Net cash provided by investing activities	65,379	58,729
Cash flows from financing activities:
Proceeds from issuance of stock from employee benefit plans	1,084	2,681
Net cash provided by financing activities	1,084	2,681
Net decrease in cash and cash equivalents	(8,295)	(20,560)
Cash and cash equivalents at beginning of period	29,429	39,143
Cash and cash equivalents at end of period	21,134	18,583
Non-cash investing activities
Accrued construction in progress	$ 488	$ 38