Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Operating activities
Net loss	$ (21,784)	$ (46,087)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	51	51
Stock-based compensation	4,159	3,774
Non-cash interest expense	718	729
Non-cash change in fair value of PIPE Warrant liability	0	(199)
Amortization of premium and discount on investments	51	50
Changes in operating assets and liabilities:
Trade receivables, net	(8,906)	(8,303)
Partnership receivables	743	(8)
Inventory	550	(1,252)
Prepaid expenses and other current assets	1,690	(651)
Operating lease right-of-use asset	97	343
Other non-current assets	(45)	(100)
Accounts payable	2,327	1,544
Accrued clinical trial costs and contract manufacturing	5,543	1,984
Accrued compensation and benefits	765	1,075
Other accrued liabilities	4,151	3,946
Operating lease liability	(9)	(8)
Deferred revenue	(578)	(1,480)
Deferred research and development reimbursements	0	(164)
Operating lease liability, non-current	0	(317)
Net cash used in operating activities	(10,477)	(45,073)
Investing activities
Purchases of marketable securities	(8,979)	(28,128)
Proceeds from maturities and sales of marketable securities	25,715	2,900
Net cash provided by (used in) investing activities	16,736	(25,228)
Financing activities
Proceeds from issuance of common stock, net of issuance costs	0	55,095
Proceeds from warrant exercises	0	3,092
Proceeds from issuance of stock for stock-based compensation arrangements	597	68
Proceeds from issuance of loan payable	0	20,000
Payment of loan maturity fees (Note 6)	0	(790)
Payment of debt issuance costs	0	(85)
Net cash provided by financing activities	597	77,380
Net increase in cash and cash equivalents	6,856	7,079
Cash and cash equivalents at beginning of period	70,542	61,761
Cash and cash equivalents at end of period	77,398	68,840
Supplemental cash flow information
Cash paid for interest	$ 3,116	$ 2,035