Accrued Expenses and Other Current Liabilities (Accrued Business Acquisition Payments) (Details) (USD $)	3 Months Ended			3 Months Ended		27 Months Ended
	Oct. 31, 2012	Oct. 31, 2011	Jul. 31, 2012	Oct. 31, 2012 Acquisition of Stampede Technologies, Inc. [Member]	Oct. 31, 2011 Acquisition of Stampede Technologies, Inc. [Member]	Oct. 31, 2012 Acquisition of Stampede Technologies, Inc. [Member]	Oct. 31, 2010 Acquisition of Stampede Technologies, Inc. [Member]
Effective date of acquisition				Oct. 01, 2010
Aggregate purchase price							$ 5,303,000
Finite-lived intangible asset, useful life				5 years
Business acquisition, contingent consideration, at fair value	1,248,000		3,519,000	1,248,000		1,248,000
Contingent earn-out period end date				Oct. 01, 2013
Benefit related to a change in fair value of contingent earn-out liability	2,378,000	0		2,378,000
Business acquisition, contingent consideration at fair value, current	1,248,000		1,752,000
Business acquisition contingent consideration interest accretion expense				108,000	122,000	961,000
Purchase price paid in cash as of the balance sheet date				1,720,000		1,720,000
Payment of contingent consideration related to business acquisition	$ 1,000	$ 63,000				$ 220,000