Condensed Consolidated Balance Sheets (Parenthetical) - USD ($)	Oct. 31, 2017	Apr. 30, 2017
Condensed Consolidated Balance Sheets [Abstract]
Accounts receivable, allowance for doubtful accounts	$ 100,000	$ 100,000
Intangible assets, amortization	$ 4,918,840	$ 4,698,765
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	500,000	500,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	12,000,000	12,000,000
Common stock, shares issued	4,202,813	4,195,813
Common stock, shares outstanding	4,202,813	4,195,813