Other Income (Expense) - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Oct. 31, 2013	Jul. 31, 2015	Jul. 31, 2014	Jul. 31, 2013
Component Of Other Expense Income Nonoperating [Line Items]
Interest expense		$ 0.6
Foreign exchange (losses)		$ (0.4)	$ (0.2)	$ (1.5)
PocketSonics
Component Of Other Expense Income Nonoperating [Line Items]
Loss from pre-acquisition equity interest	$ 0.5		$ 0.5