Accrued Expenses and Other Current Liabilities - Product Warranty Rollforward (Details) - USD ($)	3 Months Ended
	Oct. 31, 2015	Oct. 31, 2014
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	$ 8,638,000	$ 8,618,000
Provision for warranty obligations	1,200,000	1,316,000
Charges incurred	(1,136,000)	(1,216,000)
Accrued warranty obligations, as of the end of the period	$ 8,702,000	$ 8,718,000