CONDENSED CONSOLIDATED BALANCE SHEETS (Parentheticals) - USD ($)	Feb. 28, 2018	May 31, 2017
Allowance for doubtful accounts (in Dollars)	$ 54,486	$ 50,129
Accumulated depreciation and amortization (in Dollars)	$ 1,637,552	$ 1,550,073
Preferred Stock, No Par Value (in Dollars per share)	$ 0	$ 0
Preferred Stock, shares authorized	5,000,000	5,000,000
Preferred Stock, shares issued	0	0
Preferred Stock, shares outstanding	0	0
Common stock par value (in Dollars per share)	$ 0.08	$ 0.08
Common stock, shares authorized	25,000,000	25,000,000
Common stock, shares issued	8,621,929	8,511,173
Common stock, shares outstanding	8,621,929	8,511,173