Business Segment Information - Additional Information (Detail) (USD $)	3 Months Ended		12 Months Ended
	Apr. 30, 2013	Apr. 30, 2012	Jul. 31, 2014 Segment		Jul. 31, 2013		Jul. 31, 2012
Segment Reporting Information [Line Items]
Number of reportable segments			3
Gain from settlement of litigation			$ 650,000		$ 9,251,000		$ (6,698,000)
Other operating losses			835,000		9,251,000		(15,870,000)
Estimated losses from pending litigation		6,500,000
Gain (loss) from settlement of litigation	9,600,000			[1]		[1]	(11,022,000)	[1]
Loss on settlement of unrelated claim							200,000
Telecom Platform Services [Member]
Segment Reporting Information [Line Items]
Gain from settlement of litigation					9,300,000
Other operating losses							(15,900,000)
Estimated losses from pending litigation							6,500,000
Broadstripe, LLC [Member]
Segment Reporting Information [Line Items]
Gain (loss) from settlement of litigation							$ 1,800,000

[1] On October 12, 2011, the Company entered into a binding term sheet with T-Mobile USA, Inc. ("T-Mobile") to settle litigation related to an alleged breach of a wholesale supply agreement. In consideration of the settlement of all disputes between the parties, on October 13, 2011, the Company paid T-Mobile $10 million. The Company incurred legal fees of $1.0 million in fiscal 2012 in connection with this matter.