Business Combinations - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		1 Months Ended	3 Months Ended	9 Months Ended
	Apr. 30, 2013	Apr. 30, 2012	Apr. 30, 2013	Apr. 30, 2012	Mar. 02, 2013 Ultrasonix	Apr. 30, 2013 Ultrasonix	Apr. 30, 2013 Ultrasonix	Mar. 02, 2013 Ultrasonix Former Shareholders of Acquired Entity
Business Combination, Transactions [Line Items]
Purchase price, net of cash acquired					$ 79,932
Net purchase price cash payment of, net of cash acquired			79,273		79,273
Business acquisition amounts due								659
Weighted average amortization period for intangible assets							10 years
Business Acquisition, Goodwill Expected Tax Deductible Period							15 years
Acquisition related cost						548	1,210
Revenue from acquired business							3,432
Net earnings from acquisition business							(2,658)
Amortization of trade name, developed technology, customer relationships and inventory fair value and deferred revenue adjustments from purchase accounting	1,210	1,190	3,602	6,632
Adjustment of acquisition related expenses	$ 548		$ 1,210	$ 1,210