Goodwill and Other Intangible Assets - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended					6 Months Ended
	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2014	Jan. 31, 2013	Jul. 31, 2013	Jan. 31, 2014 PocketSonics	Sep. 20, 2013 PocketSonics	Jan. 31, 2014 Copley Controls	Jan. 31, 2014 Ultrasonix and PocketSonics	Jan. 31, 2014 Minimum	Jan. 31, 2014 Maximum	Jan. 31, 2014 In-process research and development PocketSonics	Jan. 31, 2014 In-process research and development Minimum	Jan. 31, 2014 In-process research and development Minimum PocketSonics	Jan. 31, 2014 In-process research and development Maximum	Jan. 31, 2014 In-process research and development Maximum PocketSonics
Goodwill and Intangible Assets Disclosure [Line Items]
Goodwill	$ 56,977,000		$ 56,977,000		$ 50,073,000	$ 2,800,000	$ 6,900,000
Acquisition of goodwill			6,900,000					1,800,000	55,200,000
Business acquisition, additional increase in goodwill												4,100,000
Intangible assets, estimated useful lives										1 year	14 years
Amortization expense related to acquired intangible assets	$ 1,900,000	$ 800,000	$ 3,800,000	$ 1,500,000
Production period													6 months	6 months	15 months	15 months