Business Segment Information - Additional Information (Detail) (USD $)	3 Months Ended			12 Months Ended
	Jul. 31, 2011	Jan. 31, 2011	Oct. 31, 2010	Jul. 31, 2012 Segment	Jul. 31, 2011	Jul. 31, 2010
Segment Reporting Disclosure [Line Items]
Number of reportable segments				2
Estimated losses from pending litigation				$ 6,468,000
Gain from litigation				1,750,000		418,000
(Loss) gain on settlement of litigation				(11,252,000)		10,000,000
Termination expense		14,400,000			14,375,000
Patent expense	1,100,000	9,800,000			10,828,000
Gain on sale of wireless spectrum license				5,330,000
Insurance claims					2,637,000
Gain (loss) on settlement of other claims			600,000		640,000	(1,500,000)
Proceeds on insurance related to water damages						485,000
Gain on sale of asset						681,000
Percentage of revenue from external customers				29.00%	32.00%	34.00%
Net long-lived assets	4,500,000			3,900,000	4,500,000	4,300,000
Total assets held outside United states	137,300,000			140,900,000	137,300,000	107,300,000
UNITED KINGDOM
Segment Reporting Disclosure [Line Items]
Percentage of revenue from external customers				14.00%	13.00%	12.00%
Telecom Platform Services [Member]
Segment Reporting Disclosure [Line Items]
Estimated losses from pending litigation				6,500,000
(Loss) gain on settlement of litigation						10,000,000
Termination expense					14,400,000
Patent expense					10,800,000
Broadstripe LLC [Member]
Segment Reporting Disclosure [Line Items]
Gain from litigation				1,800,000
T Mobile [Member]
Segment Reporting Disclosure [Line Items]
(Loss) gain on settlement of litigation				(11,000,000)
Other Services [Member]
Segment Reporting Disclosure [Line Items]
Gain from litigation						400,000
Operating gains (losses)				200,000
All Other [Member]
Segment Reporting Disclosure [Line Items]
Gain on sale of wireless spectrum license				5,300,000
Insurance claims					2,600,000
Gain (loss) on settlement of other claims					$ 600,000	$ 1,500,000