Note 6 - Common Stock and Preferred Stock (Details Textual) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2022 USD ($) $ / shares	Nov. 30, 2021 shares	Oct. 31, 2021 shares
Common Stock, Voting Rights, Vote Per Share	1
Dividends, Common Stock, Total | $	$ 0
Nonemployees [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | shares		148,480	183,100
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) | $ / shares	$ 2.00