Derivative Instruments - Additional Information (Detail) - Forward Contracts - USD ($)	3 Months Ended		9 Months Ended
	Apr. 30, 2016	Apr. 30, 2015	Apr. 30, 2016	Apr. 30, 2015	Jul. 31, 2015
Derivative [Line Items]
Notional amount of cash flow hedge instruments	$ 2,400,000		$ 2,400,000
Unrealized loss on cash flow hedges	100,000		100,000
Designated as Hedging Instrument
Derivative [Line Items]
Derivative liability, current	100,000		100,000		$ 500,000
Cost of Revenue and Operating Expenses
Derivative [Line Items]
Realized gains (losses) on cash flow hedge instruments	$ (200,000)	$ (300,000)	$ (600,000)	$ (300,000)