Other Income (Expenses) - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended			3 Months Ended	12 Months Ended
	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012	Oct. 31, 2013 PocketSonics	Jul. 31, 2014 PocketSonics
Component Of Other Expense Income Nonoperating [Line Items]
Loss from pre-acquisition equity interest				$ 0.5	$ 0.5
Foreign exchange (losses) gains	$ (0.2)	$ (1.5)	$ 0.7