Condensed Consolidated Balance Sheets (Parenthetical) - USD ($)	Feb. 29, 2020	May 31, 2019
Allowance for doubtful accounts related to accounts receivable	$ 181,000	$ 181,000
Equipment and leasehold improvements, net of accumulated depreciation and amortization	$ 273,444	$ 268,886
Preferred stock, par value	$ 1	$ 1
Preferred stock, shares authorized	500,000	500,000
Preferred stock, shares issued
Common stock, par value	$ 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	30,000	0
Preferred stock, shares issued