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Stock-based Compensation - Additional Information (Detail) - USD ($)
1 Months Ended 12 Months Ended
Jul. 31, 2013
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Weighted-average grant date fair value per share (in dollars per share)   $ 6.79 $ 7.07 $ 9.45
Aggregate intrinsic value for options exercised   $ 5,000,000 $ 2,100,000 $ 2,200,000
Fair value of options vested   6,800,000 6,500,000 3,500,000
Unrecognized compensation cost   $ 15,600,000    
Unrecognized compensation cost, weighted-average recognized period   2 years 4 months 24 days    
Tax benefit recognized related to share-based compensation cost   $ 0    
Total share-based compensation expense   $ 9,038,000 $ 6,278,000 $ 4,926,000
2004 Stock Option Plan and 2013 Equity Incentive Plan        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Shares authorized under the Plans (in shares)   6,425,421    
Stock options grant period, years   10 years    
Stock options vesting period and exercisable period, years   4 years    
Restricted stock units        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Total value of shares vested   $ 64,000    
Shares vested (in shares)   5,000 0 0
ESPP        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Length of offering period, in months 12 months      
Length of purchase periods, in months 6 months      
Purchase price percentage of fair market value of shares 85.00%      
Shares issued (in shares)   139,195 136,078 141,386
Total share-based compensation expense   $ 800,000 $ 400,000 $ 400,000
Common stock reserved for issuance (in shares)   610,166    
Share available for grant (in shares)   193,509    
ESPP | Minimum        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Contribution percentage of purchase shares on participants eligible compensation 0.00%      
ESPP | Maximum        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Contribution percentage of purchase shares on participants eligible compensation 10.00%