CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($)	Apr. 30, 2022	Apr. 30, 2021
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 3,460,288	$ 3,289,816
Accounts receivable, allowance for credit loss, noncurrent	$ 0	$ 625,963
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	1,000,000	1,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	60,000,000	40,000,000
Common stock, shares issued (in shares)	25,357,764	25,066,297
Common stock, shares outstanding (in shares)	25,202,278	24,910,811
Treasury stock (in shares)	155,486	155,486