Goodwill and Other Intangible Assets - Additional Information (Detail) (USD $)	3 Months Ended					12 Months Ended		3 Months Ended
	Oct. 31, 2013	Oct. 31, 2012	Jul. 31, 2013	Oct. 31, 2013 PocketSonics	Sep. 20, 2013 PocketSonics	Jul. 31, 2013 Minimum	Jul. 31, 2013 Maximum	Oct. 31, 2013 In Process Research And Development PocketSonics	Oct. 31, 2013 In Process Research And Development Minimum	Oct. 31, 2013 In Process Research And Development Maximum
Goodwill and Intangible Assets Disclosure [Line Items]
Goodwill	$ 56,978,000		$ 50,073,000	$ 2,800,000	$ 6,900,000
Acquisition of goodwill	6,900,000
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
Amortization period									6 months	18 months