Organization and Summary of Significant Accounting Policies (Detail Textuals) - USD ($) $ in Thousands	9 Months Ended
	Jan. 31, 2016	Apr. 30, 2015
Schedule of Equity Method Investments [Line Items]
Cash equivalents	$ 9,641	$ 5,272
EAM Trust
Schedule of Equity Method Investments [Line Items]
Non-voting profits interest ("Profits Interest")	50.00%
Percentage of revenue	100.00%
Minimum percentage of non voting profits interests due each quarter from EAM	90.00%
EAM Trust | Minimum
Schedule of Equity Method Investments [Line Items]
Percentage of non-voting revenues interest based on adjusted gross revenues	41.00%
EAM Trust | Maximum
Schedule of Equity Method Investments [Line Items]
Percentage of non-voting revenues interest based on adjusted gross revenues	55.00%