CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Revenues, net:
Total revenues, net	$ 2,393	$ 2,286	$ 4,450	$ 4,475
Costs and expenses:
Cost of royalty revenues	42	116	124	225
Research and development	12,323	8,753	23,758	15,510
General and administrative	5,089	4,067	10,762	8,190
Total costs and expenses	17,454	12,936	34,644	23,925
Loss from operations	(15,061)	(10,650)	(30,194)	(19,450)
Other expense:
Interest income	162	58	242	104
Imputed interest expense related to the sale of future royalties	(1,041)	(1,136)	(2,097)	(2,309)
Other income (expense), net	0	890	0	890
Total other expense	(879)	(188)	(1,855)	(1,315)
Net loss	$ (15,940)	$ (10,838)	$ (32,049)	$ (20,765)
Net loss per common share (basic ) (in dollars per share)	$ (0.17)	$ (0.12)	$ (0.35)	$ (0.23)
Net loss per common share (diluted) (in dollars per share)	$ (0.17)	$ (0.12)	$ (0.35)	$ (0.23)
Weighted average common shares (basic) (in shares)	91,650,950	91,547,390	91,648,175	91,527,563
Weighted average common shares (diluted) (in shares)	91,650,950	91,547,390	91,648,175	91,527,563
Net loss	$ (15,940)	$ (10,838)	$ (32,049)	$ (20,765)
Other comprehensive income:
Unrealized loss on marketable securities	(104)	6	(446)	0
Comprehensive loss	(16,044)	(10,832)	(32,495)	(20,765)
Royalties
Revenues, net:
Total revenues, net	2,474	2,348	4,534	4,535
Other revenue
Revenues, net:
Total revenues, net	0	1	0	1
Contra revenue, net
Revenues, net:
Total revenues, net	$ (81)	$ (63)	$ (84)	$ (61)