CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Operating activities:
Net loss	$ (30,001)	$ (41,101)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	61	208
Noncash interest expense	5,002	2,555
Share-based compensation expense	3,678	3,402
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	2,994	316
Other assets	(12)	(240)
Accounts payable	(1,456)	3,126
Accrued expense	(407)	(374)
Other liabilities	(130)	0
Cash used in operating activities	(20,271)	(32,108)
Investing activities:
Purchases of short-term investments	(34,529)	(7,167)
Proceeds from sales of short-term investments	51,160	36,000
Purchase of property and equipment	(20)	(205)
Cash provided by investing activities	16,611	28,628
Financing activities:
Proceeds from royalty purchase agreement	0	20,000
Proceeds from the sale of common stock, net of issuance costs	1,117	5,718
Proceeds from exercise of stock options	60	355
Cash provided by financing activities	1,177	26,073
Net decrease in cash and cash equivalents	(2,483)	22,593
Cash and cash equivalents at beginning of period	19,859	15,872
Cash and cash equivalents at end of period	17,376	38,465
Supplemental schedule of non-cash investing and financing activities:
Deferred offering costs included in accounts payable and accrued expenses	0	98
Purchase of property and equipment included in accounts payable and accrued expenses	$ 0	$ 5