Quarterly report pursuant to Section 13 or 15(d)

Common Stock - Additional Information 1 (Detail)

v3.8.0.1
Common Stock - Additional Information 1 (Detail) - USD ($)
3 Months Ended 9 Months Ended
Sep. 30, 2017
Sep. 30, 2016
Sep. 30, 2017
Sep. 30, 2016
Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Unrecognized compensation expense related to stock options granted $ 2,100,000   $ 2,100,000   $ 0
Stock Options [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Weighted-average period, restricted stock awards     3 years 10 months 25 days    
Restricted Stock Unit [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Weighted-average period, restricted stock awards     4 years    
Award vesting period     4 years    
Stock based compensation expense 100,000 $ 0 $ 100,000 $ 0  
Total unrecognized compensation expense related to the Company's restricted stock unit awards $ 600,000   $ 600,000