CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Operating expenses:
Research and development	$ 32,130	$ 31,737
General and administrative	5,942	6,615
Total operating expenses	38,072	38,352
Total operating loss	(38,072)	(38,352)
Other income (expense):
Interest income	230	52
Interest expense	(2,792)	(1,033)
Change in fair value of derivatives	(432)	557
Total other expense	(2,994)	(424)
Net loss	(41,066)	(38,776)
Preferred stock dividends	(120)	(97)
Warrant modification	(3,619)	0
Net loss applicable to common stockholders	$ (44,805)	$ (38,873)
Net loss per common share - basic (in dollars per share)	$ (0.74)	$ (0.65)
Net loss per common share - diluted (in dollars per share)	$ (0.74)	$ (0.65)
Weighted average common and potential common shares outstanding - basic (in shares)	60,159	59,391
Weighted average common and potential common shares outstanding - diluted (in shares)	60,159	59,391