CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOW - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities:
Net loss	$ (50,363)	$ (37,880)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	2,291	3,174
Amortization and premium of marketable securities, net	(3,407)	(422)
Gain on sale or disposal of assets	(23)	(29)
Intangible Asset Impairment	3,500	3,500
Gain on fair value remeasurement of contingent consideration	(1,160)	(4,236)
Non-Cash Income Tax Benefit	(227)	(228)
Stock-based compensation expense	5,813	2,658
Changes in operating assets and liabilities:
Accounts and other receivables	1,549	177
Prepaid and other current assets	(2,261)	(1,280)
Accounts payable and accrued expenses	1,757	864
Other liabilities	(3,855)	(1,491)
Net cash used in operating activities	(46,386)	(35,193)
Cash flows from investing activities:
Sales and maturities of marketable securities	129,000	55,600
Purchases of marketable securities	(325,342)	(183,394)
Acquisition of property and equipment	(895)	(1,305)
Proceeds from sale or disposal of assets	25	29
Net cash used in investing activities	(197,212)	(129,070)
Cash flows from financing activities:
Net proceeds from stock issuances	269,893	170,964
Proceeds from issuance of stock from employee benefit plans	2,053	218
Issuance of Term Loan		2,962
Payment of Term Loan		(2,962)
Net cash provided by financing activities	271,946	171,182
Net increase in cash and cash equivalents	28,348	6,919
Cash and cash equivalents at beginning of period	43,836	11,232
Cash and cash equivalents at end of period	72,184	18,151
Non-cash investing activities
Accrued construction in progress	$ 46	$ 63