Derivative Instruments - Additional Information (Detail) - Forward Contracts - USD ($) $ in Millions	12 Months Ended
	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2014
Derivative [Line Items]
Notional amount of cash flow hedge instruments	$ 18.6	$ 10.1
Unrealized loss on cash flow hedges	0.2	0.4
Designated as Hedging Instrument
Derivative [Line Items]
Derivative liability, current	0.3	0.5
Cost of Revenue and Operating Expenses
Derivative [Line Items]
Realized gains (losses) on cash flow hedge instruments	$ (0.7)	$ (0.5)	$ 0.2