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Equity Compensation Plans - Additional Information (Detail) - USD ($)
3 Months Ended 9 Months Ended 12 Months Ended
Feb. 29, 2016
Feb. 28, 2015
Feb. 29, 2016
Feb. 28, 2015
May. 31, 2016
May. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Share based compensation $ 1,462,000 $ 1,228,000 $ 4,007,000 $ 3,187,000    
Weighted-Average Grant-Date Fair Value of Options Granted           $ 11.91
During fiscal 2016            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Weighted-Average Grant-Date Fair Value of Options Granted         $ 13.11  
Employee Stock Purchase Plan | 2011 Employee Stock Purchase Plan            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Annual maximum limit percentage of compensation to purchase shares     5.00%      
Employee and Director Stock Option Plan            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Stock option vesting period     5 years      
Non-Qualified Options            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]            
Stock option vesting period     10 years