Pro Forma Information of Company as of Business Combination (Detail) (Ultrasonix, USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Apr. 30, 2013	Apr. 30, 2012	Apr. 30, 2013	Apr. 30, 2012
Ultrasonix
Business Acquisition [Line Items]
Net revenue	$ 128,865	$ 128,934	$ 407,575	$ 392,987
Net income	$ 5,045	$ 6,622	$ 20,011	$ 26,918
Net income per share, basic	$ 0.41	$ 0.54	$ 1.63	$ 2.16
Net income per share, diluted	$ 0.40	$ 0.53	$ 1.59	$ 2.13