STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Operating activities
Net loss	$ (131,071)	$ (98,565)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,793	508
Stock-based compensation	2,268	2,237
Loss from remeasurement of development derivative liability	21,182	12,507
Non-cash interest expense	304	491
Non-cash research and development expense	28,740	27,027
Other non-cash transactions	0	100
Changes in operating assets and liabilities:
Other receivables	0	1,233
Prepaid expenses and other assets	7,505	(8,375)
Accounts payable	9,010	974
Accrued expenses and other current liabilities	3,684	1,906
Deferred sublicense revenue	9,169	0
Net cash used in operating activities	(47,416)	(59,957)
Investing activities
Purchases of property and equipment	(2,679)	(1,312)
Acquisition of intellectual property rights	0	(100)
Net cash used in investing activities	(2,679)	(1,412)
Financing activities
Proceeds from development derivative liability	8,184	15,169
Proceeds from issuance of common stock in public offering, net	60,354	2,942
Payments of deferred stock offering costs	(40)	(199)
Proceeds from exercise of stock options	394	95
Shares purchased through employee stock purchase plan	336	186
Repayments of long-term debt	(5,455)	(2,727)
Net cash provided by financing activities	63,773	15,466
Net increase (decrease) in cash and cash equivalents	13,678	(45,903)
Cash and cash equivalents at the beginning of the year	28,122	74,025
Cash and cash equivalents at the end of the year	41,800	28,122
Supplemental disclosure for cash flow
Cash paid for interest	517	954
Supplemental disclosure of cash flow information
Right-of-use assets obtained in exchange for new operating lease liabilities	0	576
Issuance of warrants in conjunction with development derivative liability	0	7,925
Purchases of property and equipment in conjunction with development derivative liability	2,482	4,941
Purchases of property and equipment included in accounts payable and accrued expenses	$ 16	$ 1,378