Annual report pursuant to Section 13 and 15(d)

Common Stock - Additional Information 1 (Detail)

v3.8.0.1
Common Stock - Additional Information 1 (Detail) - USD ($)
$ / shares in Units, $ in Thousands, shares in Millions
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Weighted average fair value of stock options granted $ 2.09    
Unrecognized compensation expense related to stock options granted $ 2,000    
Estimated grant date fair value of stock options vested 600 $ 0 $ 0
Aggregate intrinsic value of options exercised 0 $ 0 $ 0
Aggregate intrinsic value of the outstanding options 0    
Aggregate intrinsic value of the exercisable outstanding options $ 0    
Effect on diluted per share on options, restricted stock units and warrants 1.7    
Stock Options [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Weighted-average period, restricted stock awards 3 years 10 months 24 days    
Stock Options [Member] | Minimum [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Award expiration period 7 years    
Stock Options [Member] | Maximum [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Award expiration period 10 years    
Stock Options [Member] | Employees and Consultants [Member] | Minimum [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Award vesting period 3 years    
Stock Options [Member] | Employees and Consultants [Member] | Maximum [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Award vesting period 4 years    
Stock Options [Member] | Board of Directors [Member] | Minimum [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Award vesting period 1 year    
Stock Options [Member] | Board of Directors [Member] | Maximum [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Award vesting period 3 years    
Restricted Stock Unit [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Award vesting period 4 years    
Weighted-average period, restricted stock awards 3 years 9 months    
Stock based compensation expense $ 100    
Total unrecognized compensation expense related to the Company's restricted stock unit awards $ 600