Goodwill And Intangible Assets (Schedule Of Inangible Assets And Goodwill) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Jan. 31, 2013	Apr. 30, 2012
Finite-Lived Intangible Assets [Line Items]
Goodwill, Gross carrying amount	$ 11,706	$ 11,706
Goodwill, Net carrying amount	11,706	11,706
Finite-lived intangible assets, Accumulated amortization	(6,038)	(4,884)
Finite-lived intangible assets, Net carrying amount	7,536
Intangible assets, Gross carrying amount	25,280	25,280
Intangible assets, Net carrying amount	19,242	20,396
Customer-Related [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, Gross carrying amount	6,236	6,236
Finite-lived intangible assets, Accumulated amortization	(3,553)	(3,043)
Finite-lived intangible assets, Net carrying amount	2,683	3,193
Finite-lived intangible assets, Weighted-average useful life	7 years	7 years
Technology-Based [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, Gross carrying amount	2,638	2,638
Finite-lived intangible assets, Accumulated amortization	(1,644)	(1,410)
Finite-lived intangible assets, Net carrying amount	994	1,228
Finite-lived intangible assets, Weighted-average useful life	5 years	5 years
Trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, Gross carrying amount	4,600	4,600
Finite-lived intangible assets, Accumulated amortization	(741)	(331)
Finite-lived intangible assets, Net carrying amount	3,859	4,269
Finite-lived intangible assets, Weighted-average useful life	10 years	10 years
Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, Gross carrying amount	100	100
Finite-lived intangible assets, Accumulated amortization	$ (100)	$ (100)
Finite-lived intangible assets, Weighted-average useful life	2 years	2 years