Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation - Additional Information (Detail)

v3.8.0.1
Stock-Based Compensation - Additional Information (Detail) - USD ($)
9 Months Ended
Sep. 30, 2017
Sep. 30, 2016
May 02, 2017
Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Common stock, issued 21,262,000     20,893,000
Restricted Share Units        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Weighted-average period 1 year 9 months 18 days      
Unrecognized compensation expense $ 800,000      
Restricted shares vested, fair value $ 1,300,000      
Stock awards vesting periods 3 years      
Restricted Stock        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Weighted-average period 2 years 9 months 18 days      
Unrecognized compensation expense $ 1,200,000      
Restricted shares vested, fair value   $ 1,100,000    
2013 Plan        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Common stock, issued     1,600,000  
2003 Plan        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Options, issued 0      
Options outstanding, intrinsic value $ 0      
Unrecognized compensation expense $ 100,000      
2003 Plan | Stock Options        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Weighted-average period 1 year