Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation and Stock Incentive Plans - Schedule of Employee Service Share-Based Compensation, Allocation of Recognized Period Costs (Detail)

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Stock-Based Compensation and Stock Incentive Plans - Schedule of Employee Service Share-Based Compensation, Allocation of Recognized Period Costs (Detail) (USD $)
In Thousands, unless otherwise specified
 3 Months Ended 6 Months Ended
Jul. 31, 2013
Jul. 31, 2012
Jul. 31, 2013
Jul. 31, 2012
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]        
Stock-based compensation expense $ 657 $ 2,004 $ 1,770 $ 3,032
Cost of Revenues [Member]
        
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]        
Stock-based compensation expense 70 77 124 194
Research and Development Expenses [Member]
        
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]        
Stock-based compensation expense 194 65 279 181
Selling and Marketing Expenses [Member]
        
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]        
Stock-based compensation expense 49 99 95 231
General and Administrative Expenses [Member]
        
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]        
Stock-based compensation expense $ 344 $ 1,763 $ 1,272 $ 2,426