Quarterly report pursuant to Section 13 or 15(d)

Stock Based Compensation Plans (Additional Information) (Detail)

v3.10.0.1
Stock Based Compensation Plans (Additional Information) (Detail) - USD ($)
3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2018
Sep. 30, 2017
Sep. 30, 2018
Sep. 30, 2017
Dec. 31, 2017
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]          
Exercisable Options Outstanding Shares 924,309   924,309    
Weighted average exercise price per share $ 4.53   $ 4.53    
Unvested Options Outstanding, Shares 465,554   465,554    
Unvested Options Outstanding, Weighted average exercise price     $ 5.72    
Weighted average remaining contractual term on unvested options     8 years 9 months 18 days    
Weighted average remaining contractual term on vested options     6 years 1 month 6 days    
Unrecognized stock compensation expense $ 2,410,000   $ 2,410,000    
Weighted average recognition period     2 years 8 months 12 days    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term     7 years   7 years 7 months 6 days
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, NonVested in Period, Fair Value $ 310,000        
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value $ 6.88        
Share-based Compensation $ 291,000 $ 425,000 $ 1,473,383 $ 912,102  
Onetime Compensation Expense     $ 384,000    
Stock Issued During Period, Shares, Other     100,000    
Shares Issued, Price Per Share $ 6.10   $ 6.10    
Stock Issued During Period, Value, Other     $ 610,000    
Aggregate Fair Market Value Of Sock Awards     122,000    
Aggregate Fair Market Value Of Sock Awards 1     488,000    
Employee Stock Option [Member]          
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]          
Unrecognized stock compensation expense $ 508,000   508,000    
Executive Officer [Member]          
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]          
Unrecognized stock compensation expense $ 232,000   $ 232,000    
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested Issued , Number 45,000