Note 4 - Property and Equipment (Details) - USD ($)	3 Months Ended		9 Months Ended
	Jan. 31, 2018	Jan. 31, 2017	Jan. 31, 2018	Jan. 31, 2017
Details
Total Depreciation Expense	$ 320,878	$ 332,714	$ 1,054,856	$ 992,590
Cost of revenues	274,270	261,775	897,938	763,806
General and administrative expenses	$ 46,608	$ 70,939	$ 156,918	$ 228,784