Accrued Expenses and Other Current Liabilities (Product Warranty Rollforward) (Details) (USD $)	12 Months Ended
	Jul. 31, 2013	Jul. 31, 2012
Accrued Liabilities, Current [Abstract]
Minimum coverage period of product warranty from the date of shipment	1 year
Changes in Product Warranty Liability
Accrued warranty obligations, as of the beginning of the period	$ 7,883,000	$ 9,120,000
Provision for warranty obligations	5,316,000	5,598,000
Charges incurred	(5,402,000)	(6,835,000)
Accrued warranty obligations, as of the end of the period	$ 7,797,000	$ 7,883,000