Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating activities
Net loss	$ (10,199)	$ (22,122)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	17	17
Stock-based compensation	1,267	1,204
Non-cash interest expense	230	140
Non-cash change in fair value of PIPE Warrant liability	0	2,396
Amortization of premium and discount on investments	72	0
Changes in operating assets and liabilities:
Trade receivables, net	(3,132)	(1,144)
Partnership receivables	959	(225)
Inventory	(38)	0
Prepaid expenses and other current assets	933	468
Operating lease right-of-use asset	99	113
Other non-current assets	0	(100)
Accounts payable	302	583
Accrued clinical trial costs and contract research	1,726	735
Accrued compensation and benefits	(1,494)	(1,414)
Other accrued liabilities	1,620	1,674
Operating lease liability	(3)	(38)
Deferred revenue	(578)	(493)
Deferred research and development reimbursements	0	(52)
Operating lease liability, non-current	0	(76)
Net cash used in operating activities	(8,219)	(18,334)
Investing activities
Purchases of marketable securities	(2,992)	0
Proceeds from maturities and sales of marketable securities	14,515	0
Net cash provided by investing activities	11,523	0
Financing activities
Proceeds from issuance of common stock, net of issuance costs	0	54,980
Proceeds from warrant exercises	0	3,092
Proceeds from issuance of loan payable	0	20,000
Payment of debt issuance costs	0	(85)
Net cash provided by financing activities	0	77,987
Net increase in cash and cash equivalents	3,304	59,653
Cash and cash equivalents at beginning of period	70,542	61,761
Cash and cash equivalents at end of period	73,846	121,414
Supplemental cash flow information
Cash paid for interest	$ 937	$ 362