v3.20.2
Stock-Based Compensation - Additional Information (Detail) - USD ($)
1 Months Ended 6 Months Ended
Jun. 30, 2020
Mar. 31, 2020
Feb. 01, 2020
Jun. 30, 2019
Aug. 01, 2020
Jun. 30, 2019
May 02, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Shares outstanding under equity incentive plans     2,000   1,802,000    
Stock-based compensation expense         $ 649,000    
Stock options granted under equity incentive plans         1,800,000    
Stock issued during period, values         $ 216,000    
Reduction in value of warrants         89,000    
Compensation expense         $ 127,000    
Expected life         5 years    
Risk-free interest rate, minimum         0.20%    
Risk-free interest rate, maximum         0.30%    
Expected dividend yield         0.00%    
Common Stock [Member]              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Number of shares granted   10,684,000          
Expected annualized volatility rate         95.00%    
Immediate Vesting Options [Member]              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Expected life         2 years 6 months    
Graded Vested Options [Member]              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Expected life         3 years 3 months 14 days    
Termination of Chief Financial Officer [Member]              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Number of shares granted       53,571      
Number of shares granted, value       $ 108,000      
Directors and Employees [Member]              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Number of shares granted           600,000  
Number of shares granted, value           $ 1,560,000  
Stock-based compensation expense           $ 1,750,000  
Employees [Member]              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Number of restricted shares granted           100,000  
Total value of restricted stock award           $ 260,000  
Stock options granted under equity incentive plans         1,800,000    
Board of Directors [Member]              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Number of shares granted         2,950,000    
Number of shares granted, value         $ 390,000    
Board of Directors [Member] | Common Stock [Member]              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Number of shares granted 804,000,000            
Number of shares granted, value $ 106,000            
Restricted Stock Award [Member]              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Stock-based compensation expense     $ 7,000   $ 53,000    
Restricted Stock Award [Member] | Termination of Chief Financial Officer [Member]              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Number of shares vested in period       26,667      
Number of shares vested in period, value       $ 69,000      
Restricted Stock Award [Member] | Employees [Member]              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Number of shares granted, vesting period           2 years  
Unregistered Shares [Member]              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Stock issued during period, shares         3,000,000    
Reduction of warrants         3,000,000    
Stock Option [Member]              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Stock-based compensation expense         $ 79,000    
2015 Equity Incentive Plan [Member]              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Shares outstanding under equity incentive plans             1,802,000
Common stock available for future issuance             2,153,000
Stock options granted under equity incentive plans     0        
2015 Equity Incentive Plan [Member] | Restricted Stock Award [Member]              
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]              
Shares outstanding under unvested restricted shares             33,000