Note 11 - Stockholders' Equity (Details Textual) - USD ($)	1 Months Ended	12 Months Ended
	Sep. 30, 2003	May 31, 2024	May 31, 2023	Sep. 01, 2016
Preferred Stock, Par or Stated Value Per Share (in dollars per share)		$ 0.0001	$ 0.0001
Warrants Exercisable Into Common Stock [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights				250,000
Class of Warrant or Right, Exercise Price of Warrants or Rights				$ 0.01
Series 2003 Preferred Stock [Member]
Stock Issued During Period, Shares, New Issues	50,000
Preferred Stock, Par or Stated Value Per Share (in dollars per share)	$ 0.0001
Stock Issued During Period, Value, New Issues	$ 5,000,000
Preferred Stock, Stated Value Per Share	$ 100
Preferred Stock, Dividend Rate, Percentage	3.25%	11.75%
Preferred Stock, Convertible, Conversion Price	$ 1.5
Convertible Preferred Stock, Shares Issued upon Conversion	3,333,333