Note 10 - Shareholders' Equity (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Aug. 31, 2021
Proceeds from Issuance of Common Stock	$ 557	$ 0
Stock Issued During Period, Exercise Of Warrants, Shares (in shares)	1,500,000
Common Stock Purchase Agreement With Nineteenth Investment Company LLC [Member]
Stock Dividends, Shares, Total (in shares)	797,450
ATM Sales Agreement [Member]
Aggregate Proceeds, Common Stock Sales			$ 50,000
Stock Issued During Period, Shares, New Issues (in shares)	200,000
Proceeds from Issuance of Common Stock	$ 600