Condensed Consolidated Balance Sheet Components - Property and Equipment, net (Detail) (USD $)
 3 Months Ended 6 Months Ended 12 Months Ended
Jan. 31, 2015
Jan. 31, 2014
Jan. 31, 2015
Jan. 31, 2014
Jul. 31, 2014
Property, Plant and Equipment [Line Items]          
Total, gross $ 104,929,000   $ 104,929,000   91,838,000
Less: accumulated depreciation and amortization (74,569,000)   (74,569,000)   (64,577,000)
Total, net 30,360,000   30,360,000   27,261,000
Depreciation and amortization expense 4,900,000 4,800,000 10,000,000 9,500,000  
Computer equipment [Member]          
Property, Plant and Equipment [Line Items]          
Total, gross 26,993,000   26,993,000   25,779,000
Computer equipment [Member] | Minimum [Member]          
Property, Plant and Equipment [Line Items]          
Estimated useful lives (in years)     2 years   2 years
Computer equipment [Member] | Maximum [Member]          
Property, Plant and Equipment [Line Items]          
Estimated useful lives (in years)     5 years   5 years
Computer software [Member]          
Property, Plant and Equipment [Line Items]          
Total, gross 19,341,000   19,341,000   16,675,000
Computer software [Member] | Minimum [Member]          
Property, Plant and Equipment [Line Items]          
Estimated useful lives (in years)     2 years   2 years
Computer software [Member] | Maximum [Member]          
Property, Plant and Equipment [Line Items]          
Estimated useful lives (in years)     5 years   5 years
Machinery and equipment [Member]          
Property, Plant and Equipment [Line Items]          
Total, gross 42,951,000   42,951,000   36,500,000
Machinery and equipment [Member] | Minimum [Member]          
Property, Plant and Equipment [Line Items]          
Estimated useful lives (in years)     2 years   2 years
Machinery and equipment [Member] | Maximum [Member]          
Property, Plant and Equipment [Line Items]          
Estimated useful lives (in years)     5 years   5 years
Furniture and fixtures [Member]          
Property, Plant and Equipment [Line Items]          
Total, gross 5,299,000   5,299,000   4,756,000
Furniture and fixtures [Member] | Minimum [Member]          
Property, Plant and Equipment [Line Items]          
Estimated useful lives (in years)     2 years   2 years
Furniture and fixtures [Member] | Maximum [Member]          
Property, Plant and Equipment [Line Items]          
Estimated useful lives (in years)     5 years   5 years
Leasehold improvements [Member]          
Property, Plant and Equipment [Line Items]          
Total, gross $ 10,345,000   $ 10,345,000   8,128,000
Leasehold improvements [Member] | Minimum [Member]          
Property, Plant and Equipment [Line Items]          
Estimated useful lives (in years)     1 year   1 year
Leasehold improvements [Member] | Maximum [Member]          
Property, Plant and Equipment [Line Items]          
Estimated useful lives (in years)     6 years   6 years