Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Operating activities
Net loss	$ (18,518)	$ (35,719)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	34	33
Stock-based compensation	2,673	2,373
Non-cash interest expense	469	428
Non-cash change in fair value of PIPE Warrant liability	0	(199)
Amortization of premium and discount on investments	57	10
Changes in operating assets and liabilities:
Trade receivables, net	(5,468)	(4,220)
Partnership receivables	940	(168)
Inventory	336	0
Prepaid expenses and other current assets	1,174	(685)
Operating lease right-of-use asset	48	227
Other non-current assets	0	(100)
Accounts payable	893	(219)
Accrued clinical trial costs and contract research	5,419	269
Accrued compensation and benefits	(726)	361
Other accrued liabilities	2,582	1,955
Operating lease liability	(6)	(45)
Deferred revenue	(578)	(987)
Deferred research and development reimbursements	0	(128)
Operating lease liability, non-current	0	(187)
Net cash used in operating activities	(10,671)	(37,001)
Investing activities
Purchases of marketable securities	(8,979)	(28,195)
Proceeds from maturities and sales of marketable securities	18,715	0
Net cash provided by (used in) investing activities	9,736	(28,195)
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	561	68
Proceeds from issuance of loan payable	0	20,000
Payment of debt issuance costs	0	(85)
Net cash provided by financing activities	561	78,170
Net (decrease) increase in cash and cash equivalents	(374)	12,974
Cash and cash equivalents at beginning of period	70,542	61,761
Cash and cash equivalents at end of period	70,168	74,735
Supplemental cash flow information
Cash paid for interest	$ 1,959	$ 1,171