Accrued Restructuring Charge (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Jul. 31, 2015	Jul. 31, 2014
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred	$ 0	$ 171
Lease Abandonment [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred		150
Other Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred		$ 21