CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Revenues, net:
Total revenues, net	$ 2,057	$ 2,189
Costs and expenses:
Cost of royalty revenues	82	109
Research and development	11,435	6,757
General and administrative	5,673	4,123
Total costs and expenses	17,190	10,989
Loss from operations	(15,133)	(8,800)
Other expense:
Interest income	80	46
Imputed interest expense related to the sale of future royalties	(1,056)	(1,173)
Total other expense	(976)	(1,127)
Net loss	$ (16,109)	$ (9,927)
Net loss per common share (basic ) (in dollars per share)	$ (0.18)	$ (0.11)
Net loss per common share (diluted) (in dollars per share)	$ (0.18)	$ (0.11)
Weighted average common shares (basic) (in shares)	91,645,369	91,507,518
Weighted average common shares (diluted) (in shares)	91,645,369	91,507,518
Net loss	$ (16,109)	$ (9,927)
Other comprehensive income:
Unrealized loss on marketable securities	(342)	(6)
Comprehensive loss	(16,451)	(9,933)
Royalties
Revenues, net:
Total revenues, net	2,060	2,187
Contra revenue, net
Revenues, net:
Total revenues, net	$ (3)	$ 2