Related Party Transactions - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended	1 Months Ended	3 Months Ended	12 Months Ended			1 Months Ended	12 Months Ended
	Jul. 31, 2012	Jul. 25, 2011 China-based affiliate	Jan. 31, 2012 China-based affiliate	Jul. 31, 2012 China-based affiliate	Jul. 31, 2011 China-based affiliate	Jul. 31, 2006 China-based affiliate	Apr. 30, 2010 PocketSonics	Jul. 31, 2013 PocketSonics	Jul. 31, 2012 PocketSonics	Jul. 31, 2011 PocketSonics
Related Party Transaction [Line Items]
Percentage of interest in affiliate sold		25.00%	25.00%
Value of interest in affiliate		$ 2,500
Book value of interest in affiliate written down						0
Gain on sale of other investments	2,500			2,500
Advance payments and deferred revenue					474
Sales to affiliate				0	2,808
Investment in start-up company							1,900
Engineering services expense								$ 898	$ 1,547	$ 2,438