Condensed Consolidated Statements of Changes in Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Total
Beginning balance (in shares) at Dec. 31, 2019	27,028,533
Beginning balance at Dec. 31, 2019	$ 27	$ 56,027	$ (56,061)	$ (7)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	$ 0	311	0	311
Issuance of common stock for license acquired, shares	1,809,845
Issuance of common stock for license acquired	$ 2	2,441	0	2,443
Issuance of common stock, net of issuance costs (in shares)	15,166,666
Issuance of common stock, net of issuance costs	$ 15	8,835	0	8,850
Net loss	$ 0	0	(4,832)	(4,832)
Ending balance (in shares) at Mar. 31, 2020	44,005,044
Ending balance at Mar. 31, 2020	$ 44	67,614	(60,893)	6,765
Beginning balance (in shares) at Dec. 31, 2020	54,535,891
Beginning balance at Dec. 31, 2020	$ 54	77,680	(75,162)	2,572
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	$ 0	705	0	$ 705
Stock Issued During Period, Shares, Stock Options Exercised	29,999			(30,000)
Stock Issued During Period, Value, Stock Options Exercised	$ 0	65	0	$ 65
Stock Issued During Period, Shares, Employee Stock Purchase Plan	40,518
Stock Issued During Period, Value, Employee Stock Purchase Plan	$ 0	30	0	30
Warrants exercised for cash, shares	6,146,125
Warrants exercised for cash	$ 6	7,017	0	7,023
Issuance of common stock, net of issuance costs (in shares)	17,530,488
Issuance of common stock, net of issuance costs	$ 18	33,463	0	33,481
Net loss	$ 0	0	(19,116)	(19,116)
Ending balance (in shares) at Mar. 31, 2021	78,283,021
Ending balance at Mar. 31, 2021	$ 78	$ 118,960	$ (94,278)	$ 24,760