CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Income Statement [Abstract]
Revenues	$ 135	$ 126	$ 234	$ 304
Operating expenses:
Research and development	7,233	4,108	9,967	8,560
Selling, general and administrative	3,220	4,305	6,460	8,722
Total operating expenses	10,453	8,413	16,427	17,282
Operating loss	(10,318)	(8,287)	(16,193)	(16,978)
Other income, net	280	52	543	49
Loss from continuing operations before income taxes	(10,038)	(8,235)	(15,650)	(16,929)
Income tax expense	0	0	0	0
Loss from continuing operations	(10,038)	(8,235)	(15,650)	(16,929)
(Loss) income from discontinued operations, net of income taxes	(20)	(241)	(30)	13,123
Net loss	$ (10,058)	$ (8,476)	$ (15,680)	$ (3,806)
Loss per share from continuing operations, basic (in dollars per share)	$ (3.08)	$ (2.56)	$ (4.81)	$ (5.38)
Loss per share from continuing operations, diluted (in dollars per share)	(3.08)	(2.56)	(4.81)	(5.38)
(Loss) income per share from discontinued operations, basic (in dollars per share)	(0.01)	(0.07)	(0.01)	4.17
(Loss) income per share from discontinued operations, diluted (in dollars per share)	(0.01)	(0.07)	(0.01)	4.17
Loss per share, basic (in dollars per share)	(3.09)	(2.63)	(4.82)	(1.21)
Loss per share, diluted (in dollars per share)	$ (3.09)	$ (2.63)	$ (4.82)	$ (1.21)
Weighted average shares outstanding - basic (in shares)	3,274	3,218	3,265	3,148
Weighted average shares outstanding - diluted (in shares)	3,274	3,218	3,265	3,148