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Stock-Based Compensation - Additional Information (Detail) - USD ($)
3 Months Ended 12 Months Ended
Mar. 31, 2016
Mar. 31, 2015
Dec. 31, 2012
Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock-based compensation expense $ 922,000 $ 702,000    
Stock options, outstanding 1,312,508 1,295,312   1,240,935
Number of shares available for future grant 2,085,727      
Closing price of common stock $ 26.82      
Weighted average grant date fair value of share-based awards granted $ 19.57 $ 19.67    
Total fair value of stock options vested $ 1,387,000 $ 671,000    
Total unrecognized compensation cost $ 9,764,000      
Unrecognized compensation cost, weighted average remaining requisite service period 2 years 11 months 5 days      
Number of unvested options 703,639      
Unvested Options        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Incentive options, vesting period 5 years      
Employee Stock Option | Minimum        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Incentive options, vesting period     3 years  
Employee Stock Option | Minimum | Vest Over Three Year        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Incentive options, vesting percentage     20.00%  
Employee Stock Option | Maximum        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Incentive options, vesting period     5 years  
Incentive options, term     10 years  
Employee Stock Option | Maximum | Vest Over Five Year        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Incentive options, vesting percentage     33.00%  
Non-Employee Directors        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Incentive options, vesting period     1 year