Note 9 - Preferred Stock and Common Stock Warrants - Allocation of Net Cash Proceeds (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Gross proceeds	$ 10,500	$ 39,500
Equity issuance costs	(20)	(62)
Net proceeds - Initial Fair Value Allocation	10,480	39,438
Series C Convertible Preferred Stock [Member]
Net proceeds - Initial Fair Value Allocation	9,836	37,807
Per balance sheet upon issuance	9,836	37,807
Series C Warrants [Member]
Net proceeds - Initial Fair Value Allocation	644	1,631
Per balance sheet upon issuance	$ 644	$ 1,631