Quarterly report pursuant to Section 13 or 15(d)

Common Stock - Additional Information 2 (Detail)

v3.10.0.1
Common Stock - Additional Information 2 (Detail) - USD ($)
3 Months Ended 6 Months Ended
Jun. 30, 2018
Jun. 30, 2018
Dec. 31, 2017
Jun. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Unrecognized compensation expense related to stock options granted $ 1,600,000 $ 1,600,000 $ 2,000,000  
Common shares reserved for awards currently outstanding       0
Stock Options [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Weighted-average period, restricted stock awards   3 years    
Restricted Stock Unit [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Weighted-average period, restricted stock awards   3 years    
Award vesting period   4 years    
Stock based compensation expense $ 37,000 $ 37,000    
Common shares reserved for awards currently outstanding 20,394 20,394 21,066  
Total unrecognized compensation expense related to the Company's restricted stock unit awards $ 500,000 $ 500,000