Note 2 - Earning Per Share - Schedule of Basic and Diluted Earnings Per Share (Details) - USD ($)	3 Months Ended		6 Months Ended
	Nov. 30, 2023	Nov. 30, 2022	Nov. 30, 2023	Nov. 30, 2022
Net income attributable to common stockholders	$ 818,354	$ (306,596)	$ 2,416,374	$ 908,128
Net income (loss) attributable to common stockholders	$ 818,354	$ (306,596)	$ 2,416,374	$ 908,128
Basic (in shares)	28,279,701	28,279,701	28,279,701	28,279,701
Basic (in dollars per share)	$ 0.03	$ (0.01)	$ 0.09	$ 0.03
Net income (loss) attributable to common stockholders	$ 818,354	$ (306,596)	$ 2,416,374	$ 908,128
Preferred Stock Dividends, Income Statement Impact			0	0
Net income allocated to common stockholders	$ 818,354	$ (306,596)	$ 2,416,374	$ 908,128
Incremental shares from assumed conversion of options, warrants and preferred stock, as appropriate (in shares)	495,079	0	494,861	493,506
Weighted average common stock outstanding – diluted (in shares)	28,774,780	28,279,701	28,774,562	28,773,207
Diluted (in dollars per share)	$ 0.03	$ (0.01)	$ 0.08	$ 0.03
Weighted average common stock outstanding - diluted (in shares)	28,774,780	28,279,701	28,774,562	28,773,207