Quarterly Results of Operations - Additional information (Detail) (USD $)	1 Months Ended	3 Months Ended			12 Months Ended			3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended		3 Months Ended				12 Months Ended
	May 31, 2013	Jan. 31, 2014	Jul. 31, 2013	Apr. 30, 2013	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2014 2014 Restructuring Plan	Jan. 31, 2014 Fiscal Two Thousand Thirteen Restructuring Plan	Jul. 31, 2014 Fiscal Two Thousand Thirteen Restructuring Plan	Oct. 31, 2013 PocketSonics	Jul. 31, 2014 PocketSonics	Apr. 30, 2010 PocketSonics	Jul. 31, 2014 Ultrasonix	Jul. 31, 2013 Ultrasonix	Apr. 30, 2013 Ultrasonix	Jan. 31, 2013 Ultrasonix	Jul. 31, 2014 Ultrasonix
Schedule Of Quarterly Financial Information [Line Items]
Restructuring charge	$ 3,500,000		$ 3,000,000	$ 500,000	$ 3,483,000	$ 3,519,000	$ 2,900,000	$ 600,000	$ 600,000				$ 2,900,000
Loss from pre-acquisition equity interest										500,000	500,000
Ownership interests												10.00%
Discrete tax benefit		(8,800,000)
Acquisition related cost											$ 100,000			$ 3,100,000	$ 1,900,000	$ 700,000	$ 8,700,000