STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Operating activities
Net loss	$ (98,565)	$ (39,247)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	508	174
Stock-based compensation	2,237	1,421
Loss from remeasurement of development derivative liability	12,507	0
Non-cash interest expense	491	500
Non-cash research and development expense	27,027	0
Other non-cash transactions	100	0
Changes in operating assets and liabilities:
Other receivables	1,233	(1,000)
Prepaid expenses and other assets	(8,375)	(1,954)
Accounts payable	974	802
Accrued expenses	1,906	(327)
Deferred rent	0	37
Net cash used in operating activities	(59,957)	(39,594)
Investing activities
Purchases of property and equipment	(1,312)	(960)
Acquisition of intellectual property rights	(100)	0
Net cash used in investing activities	(1,412)	(960)
Financing activities
Proceeds from development derivative liability	15,169	0
Proceeds from issuance of common stock, net	2,942	46,277
Payments of deferred stock offering costs	(199)	(145)
Long-term borrowings, net	0	8,089
Proceeds from exercise of stock options	95	245
Shares purchased through employee share purchase plan	186	0
Repayments of long-term debt	(2,727)	(938)
Net cash provided by financing activities	15,466	53,528
Net (decrease) increase in cash and cash equivalents	(45,903)	12,974
Cash, cash equivalents and restricted cash at the beginning of the year	74,025	61,051
Cash and cash equivalents at the end of the year	28,122	74,025
Supplemental disclosure for cash flow
Cash paid for interest	954	576
Supplemental disclosure of cash flow information
Accrued interest on term loan refinanced to principal	0	308
Debt refinanced through new term loan	0	6,563
Right-of-use assets obtained in exchange for new operating lease liabilities	576	1,991
Issuance of warrants in conjunction with development derivative liability	7,925	0
Purchases of property and equipment in conjunction with development derivative liability	4,941	0
Issuance of warrants in conjunction with debt	0	355
Deferred stock offering costs in accounts payable	0	110
Purchases of property and equipment included in accounts payable and accrued expenses	$ 1,378	$ 823