Assets and Liabilities Carried at Fair Value Measured on Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	Nov. 19, 2010	Jul. 31, 2012 Fair Value, Measurements, Recurring	Jul. 31, 2011 Fair Value, Measurements, Recurring	Jul. 31, 2012 Fair Value, Measurements, Recurring Fair Value, Inputs, Level 1	Jul. 31, 2012 Fair Value, Measurements, Recurring Fair Value, Inputs, Level 2	Jul. 31, 2011 Fair Value, Measurements, Recurring Fair Value, Inputs, Level 2	Jul. 31, 2012 Fair Value, Measurements, Recurring Fair Value, Inputs, Level 3	Jul. 31, 2011 Fair Value, Measurements, Recurring Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents		$ 14,590	$ 9,600		$ 14,590	$ 9,600
Foreign currency forward contracts		66		66
Total assets		14,656	9,600	66	14,590	9,600
Contingent consideration	340	460	340				460	340
Total liabilities		$ 460	$ 340				$ 460	$ 340