Assets and Liabilities Carried at Fair Value Measured on Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	Nov. 19, 2010	Jul. 31, 2013 Fair Value, Measurements, Recurring		Jul. 31, 2012 Fair Value, Measurements, Recurring		Jul. 31, 2013 Fair Value, Measurements, Recurring Fair Value, Inputs, Level 1		Jul. 31, 2012 Fair Value, Measurements, Recurring Fair Value, Inputs, Level 1		Jul. 31, 2013 Fair Value, Measurements, Recurring Fair Value, Inputs, Level 2	Jul. 31, 2012 Fair Value, Measurements, Recurring Fair Value, Inputs, Level 2	Jul. 31, 2012 Fair Value, Measurements, Recurring Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents		$ 753		$ 14,590						$ 753	$ 14,590
Plan assets for deferred compensation		2,725	[1]	1,693	[1]	2,725	[1]	1,693	[1]
Total assets at fair value		3,478		16,349		2,725		1,693		753	14,656
Foreign currency forward contracts		160								160
Total liabilities at fair value		160		460						160		460
Foreign currency forward contracts				66							66
Contingent consideration	$ 340			$ 460	[2]							$ 460	[2]

[1] Assets held in the deferred compensation plan will be used to pay benefits under our non-qualified deferred compensation plan. The investments consist primarily of mutual funds.

[2] The amount of contingent consideration related to the acquisition to acquire certain assets of an OEM ultrasound transducer and probe business in November 2010. During our quarter ended January 31, 2013, we paid $435 in contingent consideration and have no further obligation.