Note 13 - Treasury Stock and Repurchase Program (Details Textual) - USD ($)	May 31, 2022	Mar. 31, 2022	Mar. 14, 2022	Jul. 31, 2021	Apr. 30, 2020
Stock Repurchase Program, Authorized Amount	$ 3,000,000	$ 2,000,000	$ 2,000,000	$ 2,000,000	$ 2,000,000