Quarterly report pursuant to Section 13 or 15(d)

Note 9 - Stockholders' Equity (Details Textual)

v3.21.2
Note 9 - Stockholders' Equity (Details Textual) - USD ($)
1 Months Ended 3 Months Ended 6 Months Ended
Apr. 23, 2021
Jun. 30, 2020
Apr. 30, 2020
Jun. 30, 2011
Jun. 30, 2021
Jun. 30, 2021
Jun. 30, 2020
Dec. 31, 2020
Dec. 31, 2019
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)   $ 1.95     $ 2.15 $ 2.15 $ 1.95 $ 1.97 $ 0.50
Deferred Compensation Arrangement with Individual, Shares Authorized for Issuance (in shares)   2,519,630     2,408,151 2,408,151 2,519,630 2,428,329 2,375,760
Share-based Payment Arrangement, Option [Member]                  
Share-based Payment Arrangement, Amount Capitalized           $ 286,000 $ 48,000    
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total         $ 3.5 $ 3.5      
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)           4 years 4 months 24 days      
Share-based Payment Arrangement, Option [Member] | Share-based Payment Arrangement, Employee [Member]                  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)           2,032,175 0    
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Minimum           0.19%      
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Maximum           1.15%      
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Minimum           69.10%      
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Maximum           94.00%      
Share-based Payment Arrangement, Expense         $ 4,800 $ 15,000 $ 7,000    
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate           0.00%      
Share-based Payment Arrangement, Option [Member] | Share-based Payment Arrangement, Employee [Member] | Maximum [Member]                  
Share Price (in dollars per share)         $ 3.79 $ 3.79      
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term (Year)           6 years 6 months      
Share-based Payment Arrangement, Option [Member] | Share-based Payment Arrangement, Employee [Member] | Minimum [Member]                  
Share Price (in dollars per share)         2.46 $ 2.46      
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term (Year)           3 years      
Share-based Payment Arrangement, Option [Member] | Share-based Payment Arrangement, Nonemployee [Member]                  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares)           16,666 8,333    
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Minimum           86.97%      
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Maximum           94.05%      
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term (Year)           5 years      
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate           0.30%      
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate           0.00%      
Share-based Payment Arrangement, Option [Member] | Share-based Payment Arrangement, Nonemployee [Member] | Maximum [Member]                  
Share Price (in dollars per share)         4.30 $ 4.30      
Share-based Payment Arrangement, Option [Member] | Share-based Payment Arrangement, Nonemployee [Member] | Minimum [Member]                  
Share Price (in dollars per share)         $ 3.57 $ 3.57      
Restricted Stock [Member]                  
Share-based Payment Arrangement, Expense         $ 20,833 $ 20,833      
Stock Option Plan 2011 [Member]                  
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares)       2,000,000          
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized (in shares)       4,000,000          
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercise Period from Grant Date (Year)       3 years          
Share-based Compensation Arrangement by Share-based Payment Award, Options, Expire Period after Grant Date (Year)       5 years          
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in shares)         2,471,659 2,471,659   424,425  
The 2020 Equity Incentive Plan [Member] | Share-based Payment Arrangement, Option [Member]                  
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized (in shares)           4,000,000      
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)           3 years      
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)           5 years      
Chief Executive Officer, Chief Financial Officer and Employees [Member]                  
Deferred Compensation Arrangement with Individual, Shares Authorized for Issuance (in shares)   2,370,345     2,264,127 2,264,127 2,370,345    
Non-Employees [Member]                  
Common Stock, Capital Shares Reserved for Future Issuance (in shares)   149,285     144,024 144,024 149,285    
Vice Chairman of the Board of Directors [Member] | The 2020 Equity Incentive Plan [Member] | Share-based Payment Arrangement, Option [Member]                  
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year) 5 years                
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in shares) 2,000,000                
Warrants Associated With April 2020 Public Offering [Member]                  
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)     2,710,000            
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)     $ 1.20            
Warrants Associated With the June 2020 Public Offering [Member]                  
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)   3,749,000         3,749,000    
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)   $ 2.60         $ 2.60    
April 6, 2020 Public Offering [Member]                  
Proceeds from Issuance of Common Stock, Gross     $ 5,100,000            
Stock Issued During Period, Shares, New Issues (in shares)     5,420,000            
Share Price (in dollars per share)     $ 0.95            
June 30, 2020 Public Offering [Member]                  
Proceeds from Issuance of Common Stock, Gross   $ 14,600,000              
Stock Issued During Period, Shares, New Issues (in shares)   6,770,000              
Share Price (in dollars per share)   $ 2.15         $ 2.15