Accrued Expenses and Other Current Liabilities (Accrued Business Acquisition Payments) (Details) (USD $)	6 Months Ended			3 Months Ended		6 Months Ended		30 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jul. 31, 2012	Jan. 31, 2013 Acquisition of Stampede Technologies, Inc. [Member]	Jan. 31, 2012 Acquisition of Stampede Technologies, Inc. [Member]	Jan. 31, 2013 Acquisition of Stampede Technologies, Inc. [Member]	Jan. 31, 2012 Acquisition of Stampede Technologies, Inc. [Member]	Jan. 31, 2013 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	375,000		3,519,000	375,000		375,000		375,000
Contingent earn-out period end date						Oct. 01, 2013
Benefit related to a change in fair value of contingent earn-out liability	3,267,000	0		889,000	0	3,267,000	0
Business acquisition, contingent consideration at fair value, current	375,000		1,752,000
Business acquisition contingent consideration interest accretion expense				25,000	119,000	133,000	241,000	986,000
Purchase price paid in cash as of the balance sheet date				1,729,000		1,729,000		1,729,000
Payment of contingent consideration related to business acquisition	$ 10,000	$ 157,000						$ 229,000