Quarterly report pursuant to Section 13 or 15(d)

Nature of Business and Basis of Presentation - Additional Information (Detail)

v2.4.0.8
Nature of Business and Basis of Presentation - Additional Information (Detail) (USD $)
In Millions, except Share data, unless otherwise specified
1 Months Ended 6 Months Ended
May 01, 2012
Jul. 31, 2013
Increment
Organization Consolidation And Presentation Of Financial Statements [Abstract]    
Share-based compensation arrangement by share-based payment award, options, grants in period, gross 875,000  
Number of increments related to vesting of stock options   3
Share-based compensation arrangement by share-based payment award, options, vested and expected to vest, outstanding, number   437,500
Share-based compensation arrangement by share-based payment award, options, vested in period, fair value   $ 3.3
Share-based compensation arrangement by Share-based payment award, award requisite service period   2 years 1 month 6 days
Period of service condition of vesting iterations   36 months
Number of stock options vest in first increment   291,667
Number of stock options vest in second increment   291,666
Number of stock options vest in third increment   291,667
Derived service period for first increment   7 months 6 days
Derived service period for two increment   9 months 18 days
Derived service period for three increment   10 months 24 days
Additional stock compensation   $ 1.8