Condensed Consolidated Balance Sheets (Parenthetical) - USD ($)	Oct. 31, 2020	Apr. 30, 2020
Condensed Consolidated Balance Sheets [Abstract]
Accounts receivable, allowance for doubtful accounts	$ 395,969	$ 727,252
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	4,257,508	4,242,508
Common stock, shares outstanding	4,257,508	4,242,508