CONDENSED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating activities
Net loss	$ (27,358)	$ (14,905)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	474	54
Stock-based compensation	670	471
Loss from remeasurement of development derivative liability	1,426	454
Non-cash interest expense	93	132
Non-cash research and development expense	11,798	557
Other non-cash transactions	0	100
Changes in operating assets and liabilities:
Other receivables	0	337
Prepaid expenses and other assets	965	(9,602)
Accounts payable	2,199	(712)
Accrued expenses and other current liabilities	(467)	(713)
Net cash used in operating activities	(10,200)	(23,827)
Investing activities
Purchases of property and equipment	(133)	(558)
Acquisition of intellectual property rights	0	(100)
Net cash used in investing activities	(133)	(658)
Financing activities
Proceeds from development derivative liability	0	10,000
Proceeds from issuance of common stock in public offering, net	60,536	0
Payments of deferred stock offering costs	0	(116)
Proceeds from exercise of stock options	2	17
Repayments of long-term debt	(1,364)	0
Net cash provided by financing activities	59,174	9,901
Net increase (decrease) in cash and cash equivalents	48,841	(14,584)
Cash and cash equivalents at the beginning of the period	28,122	74,025
Cash and cash equivalents at the end of the period	76,963	59,441
Supplemental disclosure for cash flow
Cash paid for interest	192	246
Supplemental disclosure of non-cash investing and financing activities
Issuance of warrants in conjunction with development derivative liability	0	7,925
Stock offering costs included in accounts payable and accrued expenses	370	45
Purchases of property and equipment by incurring development derivative liability	3,317	0
Purchases of property and equipment included in accounts payable and accrued expenses	$ 969	$ 1,031