COMMITMENTS AND CONTINGENCIES: (Details Textual) - USD ($)	12 Months Ended
	Apr. 30, 2017	Apr. 30, 2016
Commitments And Contingencies [Line Items]
Operating Leases, Rent Expense	$ 788,000	$ 1,116,000
Operating Leases, Future Minimum Payments Due	663,000
Operating Leases, Future Minimum Payments Due, Next Twelve Months	226,000
Operating Leases, Future Minimum Payments, Due in Two Years	220,000
Operating Leases, Future Minimum Payments, Due in Three Years	99,000
Operating Leases, Future Minimum Payments, Due in Four Years	92,000
Operating Leases, Future Minimum Payments, Due Thereafter	26,000
Future Development Commitments	$ 873,000