Derivative Instruments - Additional Information (Detail) (Forward Contracts)				3 Months Ended		9 Months Ended
	Apr. 30, 2015 USD ($)	Apr. 30, 2015 CAD	Jul. 31, 2014 USD ($)	Apr. 30, 2015 Cost of Revenue and Operating Expenses USD ($)	Apr. 30, 2014 Cost of Revenue and Operating Expenses USD ($)	Apr. 30, 2015 Cost of Revenue and Operating Expenses USD ($)	Apr. 30, 2014 Cost of Revenue and Operating Expenses USD ($)
Derivative [Line Items]
Notional amount of cash flow hedge instruments		2,700,000	$ 0
Unrealized loss on cash flow hedges	100,000
Realized gains (losses) on cash flow hedge instruments				$ (300,000)	$ 100,000	$ (300,000)	$ (200,000)