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Line of Credit - Additional Information (Detail) - USD ($)
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Apr. 29, 2019
Jan. 01, 2019
Dec. 19, 2017
Dec. 30, 2010
Line of Credit Facility [Line Items]            
Number of securities called by warrant 500,000     3,579,642    
Exercise price of warrant           $ 7.20
Warrant value $ 696,000          
Expected life 6 years 5 years 8 months 12 days        
Expected Volatility 103.70% 103.50%        
Expected dividend 0.00% 0.00%        
Risk free interest rate 2.68% 2.47%        
Amortization of interest expense $ 87,000 $ 336,000        
Unsecured Line Of Credit | Director            
Line of Credit Facility [Line Items]            
Line of credit facility         $ 10,000,000  
Short term borrowing interest rate 1.60%          
Number of securities called by warrant 1,000,000 1,000,000        
Exercise price of warrant $ 5 $ 5        
Line of credit current $ 0 $ 0        
Warrant            
Line of Credit Facility [Line Items]            
Exercise price of warrant     $ 7.00      
Expected life 7 years          
Expected Volatility 98.00%          
Expected dividend 0.00%          
Risk free interest rate 2.05%