Consolidated Balance Sheets (Parentheticals) - USD ($)	May 31, 2021	May 31, 2020
Allowance for doubtful accounts related to accounts receivable (in Dollars)	$ 181,000	$ 181,000
Preferred stock par value (in Dollars per share)	$ 1	$ 1
Preferred stock, shares authorized	500,000	500,000
Preferred stock, shares issued
Common stock par value (in Dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	12,500,000	12,500,000
Common stock, shares issued	3,114,163	3,114,163
Common stock, shares outstanding	1,962,062	1,962,062
Treasury stock, shares	1,152,101	1,152,101
Class A Preferred Stock
Preferred stock, shares authorized	0	30,000
Preferred stock, shares issued