Goodwill and Intangible Assets - Summary of Amortization Expense of Intangible Assets (Detail) (USD $)
In Thousands, unless otherwise specified
3 Months Ended 6 Months Ended
Jan. 31, 2015
Jan. 31, 2014
Jan. 31, 2015
Jan. 31, 2014
Finite Lived Intangible Assets Amortization Expense [Line Items]        
Amortization expense of intangible assets $ 2,106 $ 2,384 $ 4,266 $ 4,748
Cost of product revenue [Member]        
Finite Lived Intangible Assets Amortization Expense [Line Items]        
Amortization expense of intangible assets 1,941 2,025 3,936 4,030
Sales and marketing [Member]        
Finite Lived Intangible Assets Amortization Expense [Line Items]        
Amortization expense of intangible assets 144 353 288 706
Research & development [Member]        
Finite Lived Intangible Assets Amortization Expense [Line Items]        
Amortization expense of intangible assets 6 6 13 12
General and administrative [Member]        
Finite Lived Intangible Assets Amortization Expense [Line Items]        
Amortization expense of intangible assets $ 15 $ 0 $ 29 $ 0