Accrued Restructuring Charges (Schedule Of Accrued Liability Associated With Realignment) (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2015	Apr. 30, 2014
Restructuring Cost and Reserve [Line Items]
Accrued liability at April 30, 2014	$ 560
Charges	117	$ 1,197
Payments, net	(513)	(637)
Adjustments	60
Accrued liability at April 30, 2015	224	560
Severance [Member]
Restructuring Cost and Reserve [Line Items]
Accrued liability at April 30, 2014	96
Charges		414
Payments, net	(96)	(318)
Accrued liability at April 30, 2015		96
Lease Abandonment [Member]
Restructuring Cost and Reserve [Line Items]
Accrued liability at April 30, 2014	464
Charges	117	783
Payments, net	(417)	(319)
Adjustments	60
Accrued liability at April 30, 2015	$ 224	$ 464