INCOME TAXES: (Details Textual) - USD ($)	12 Months Ended
	Apr. 30, 2017	Apr. 30, 2016
Operating Loss Carryforwards State Subject To Expiration Current	$ 84,943,000
Operating Loss Carryforwards State Subject To Expiration In One Years	0
Operating Loss Carryforwards State Subject To Expiration In Two Years	0
Operating Loss Carryforwards State Subject To Expiration In Three Years	2,003,000
Operating Loss Carryforwards State Subject To Expiration In Four Years	550,000
Operating Loss Carryforwards State Subject To Expiration In five Years	32,000
Operating Loss Carryforwards State Subject To Expiration In Thereafter	82,358,000
Unrecognized Tax Benefits, Period Increase (Decrease)	58,000	$ 58,000
Deferred Tax Assets, Valuation Allowance	4,636,000	4,567,000
Income Tax Examination, Penalties and Interest Accrued	$ 50,000	$ 0