CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOW - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities:
Net loss	$ (23,050)	$ (16,538)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	811	775
Amortization and premium of marketable securities, net	772	(48)
Gain on sale or disposal of assets		(24)
(Gain) loss on fair value remeasurement of contingent consideration	(536)	483
Stock-based compensation expense	3,153	1,275
Changes in operating assets and liabilities:
Accounts and other receivables	(71)	(26)
Prepaid and other current assets	(7,148)	(2,137)
Accounts payable and accrued expenses	(2,738)	(1,266)
Other liabilities	4,273	(578)
Net cash used in operating activities	(24,534)	(18,084)
Cash flows from investing activities:
Sales and maturities of marketable securities	27,845	78,000
Purchases of marketable securities	(16,890)	(33,970)
Acquisition of property and equipment	(575)	(567)
Proceeds from sale or disposal of assets		24
Net cash provided by investing activities	10,380	43,487
Cash flows from financing activities:
Proceeds from issuance of stock from employee benefit plans	304	74
Net cash provided by financing activities	304	74
Net (decrease) increase in cash and cash equivalents	(13,850)	25,477
Cash and cash equivalents at beginning of period	39,143	43,836
Cash and cash equivalents at end of period	25,293	$ 69,313
Non-cash investing activities
Accrued construction in progress	$ 53