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Stock Options and Restricted Stock - Summary of Activity for Unvested Options Outstanding (Detail) - $ / shares
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Sharebased Compensation Arrangement By Sharebased Payment Award Options Nonvested Number Of Shares Roll Forward      
Number of options beginning balance 487,262    
Number of options, granted 444,557 449,450 39,000
Number of options, cancelled (20,630)    
Number of options, vested (137,827)    
Number of options ending balance 773,362 487,262  
Exercise price per share beginning balance, Lower limit $ 2.14    
Exercise price per share beginning balance, Upper limit 7.25    
Exercise price per share, Granted, Lower limit 4.89    
Exercise price per share, Granted, Upper limit 6.68    
Exercise price per share, Cancelled, Lower limit 6.55    
Exercise price per share, Cancelled, Upper limit 7.25    
Exercise price per share, Vested, Lower limit 2.14    
Exercise price per share, Vested, Upper limit 6.55    
Exercise price per share ending balance, Lower limit 4.89 $ 2.14  
Exercise price per share ending balance, Upper limit 7.25 7.25  
Weighted average exercise price 6.45    
Weighted average exercise price, granted 6.24    
Weighted average exercise price, cancelled 6.76    
Weighted average exercise price, vested 6.05    
Weighted average exercise price $ 6.42 $ 6.45