Commitments, Guarantees and Contingencies - Additional Information (Detail) - USD ($)		12 Months Ended
	Oct. 11, 2011	Jul. 31, 2015	Jul. 31, 2014
Commitments and Contingencies Disclosure [Line Items]
Liabilities related to agreements		$ 0
Deferred revenue for product extended warranty contracts		6,100,000	$ 11,800,000
Revolving credit agreement period	5 years
Business exit cost		1,400,000	1,400,000
Accrued litigation charge		1,600,000
Other Liabilities
Commitments and Contingencies Disclosure [Line Items]
Asset retirement obligations, estimated cost of restoring our leased facilities		1,200,000	1,100,000
Product Extended Warranty Contracts
Commitments and Contingencies Disclosure [Line Items]
Deferred revenue for product extended warranty contracts		$ 5,300,000	7,400,000
Revolving Credit Facility
Commitments and Contingencies Disclosure [Line Items]
Credit facility maximum borrow capacity	$ 100,000,000
Credit facility, expiry date	Oct. 10, 2016
Percentage of capital stock pledge as collateral	65.00%
Leverage ratio		0.40%
Credit facility transaction costs incurred		$ 500,000
Credit facility, maturity period		5 years
Line of credit amount outstanding		$ 0	$ 0
Revolving Credit Facility | Other Revolving Credit Facilities
Commitments and Contingencies Disclosure [Line Items]
Credit facility available borrowing capacity		$ 1,200,000
Minimum
Commitments and Contingencies Disclosure [Line Items]
Standard product warranty term		12 months
Minimum | Revolving Credit Facility
Commitments and Contingencies Disclosure [Line Items]
Credit facility commitment fee percentage	0.20%
Interest coverage ratio		300.00%
Minimum | Revolving Credit Facility | LIBOR Rate
Commitments and Contingencies Disclosure [Line Items]
Variable interest rate	1.25%
Minimum | Revolving Credit Facility | Base Rate
Commitments and Contingencies Disclosure [Line Items]
Variable interest rate	0.00%
Maximum
Commitments and Contingencies Disclosure [Line Items]
Standard product warranty term		60 months
Maximum | Revolving Credit Facility
Commitments and Contingencies Disclosure [Line Items]
Aggregate available credit amount under specified circumstances	$ 150,000,000
Credit facility commitment fee percentage	0.35%
Leverage ratio of total debt to earnings before interest, taxes, depreciation, and amortization or EBITDA		275.00%
Maximum | Revolving Credit Facility | LIBOR Rate
Commitments and Contingencies Disclosure [Line Items]
Variable interest rate	2.00%
Maximum | Revolving Credit Facility | Base Rate
Commitments and Contingencies Disclosure [Line Items]
Variable interest rate	1.00%