Acquisitions (Details) (USD $)	12 Months Ended					24 Months Ended		12 Months Ended
	Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2010	Jul. 31, 2012 Acquisition of Stampede Technologies, Inc. [Member]	Jul. 31, 2011 Acquisition of Stampede Technologies, Inc. [Member]	Jul. 31, 2012 Acquisition of Stampede Technologies, Inc. [Member]	Oct. 31, 2010 Acquisition of Stampede Technologies, Inc. [Member]	Jul. 31, 2012 Technologies [Member]	Jul. 31, 2011 Technologies [Member]
Business Acquisition [Line Items]
Effective date of acquisition				Oct. 01, 2010
Name of Acquired Entity				Stampede Technologies, Inc.
Aggregate purchase price							$ 5,303,000
Finite-lived intangible asset, useful life				5 years				11 years 8 months 12 days	10 years 2 months 12 days
Business acquisition, contingent consideration, at fair value				3,519,000		3,519,000
Contingent earn-out period end date				Oct. 01, 2013
Business acquisition, contingent consideration at fair value, current	1,752,000	726,000		1,752,000		1,752,000
Business acquisition, contingent consideration at fair value, noncurrent				1,767,000		1,767,000
Purchase price paid in cash as of the balance sheet date				1,719,000		1,719,000
Payment of contingent consideration related to business acquisition	195,000	24,000	0			219,000
Business acquisition contingent consideration interest accretion expense				$ 462,000	$ 391,000	$ 853,000