12. Employee Benefit Plans (Details) - Schedule of Share-based Compensation, Stock Options, Activity - USD ($)	12 Months Ended
	Apr. 30, 2019	Apr. 30, 2018	Apr. 30, 2017
Schedule of Share-based Compensation, Stock Options, Activity [Abstract]
Options, Shares Outstanding	1,488,000		1,635,125
Options, Weighted-Average Exercise Price (in Dollars per share)	$ 8.93		$ 9.00
Options, Weighted Average Remaining Contractual Term	3 years	3 years 255 days	4 years 109 days
Options, Aggregate Intrinsic Value (in Dollars)	$ 1,462,713
Options, Shares Exercisable	1,216,000
Options, Weighted-Average Exercise Price Exercisable (in Dollars per share)	$ 9.12
Options, Weighted Average Remaining Contractual Term Exercisable	2 years 328 days
Options, Aggregate Intrinsic ValueExercisable (in Dollars)	$ 5,704,588
Available for future grants	81,966
Options, Shares Granted	162,500	25,000
Options, Weighted-Average Exercise Price Granted (in Dollars per share)	$ 8.50	$ 8.06
Options, Shares Exercised	(145,750)	(3,500)
Options, Weighted-Average Exercise Price Exercised (in Dollars per share)	$ 5.95	$ 6.92
Options, Aggregate Intrinsic Value Exercised (in Dollars)	$ 889,588	$ 6,645
Options, Shares Expired or Canceled	(5,000)	(168,625)
Options, Weighted-Average Exercise Price Expired or Canceled (in Dollars per share)	$ 9.55	$ 9.54
Options, Shares Outstanding	1,499,750	1,488,000
Options, Weighted-Average Exercise Price (in Dollars per share)	$ 9.17	$ 8.93
Options, Aggregate Intrinsic Value (in Dollars)	$ 6,660,150	$ 1,462,713