Quarterly report pursuant to Section 13 or 15(d)

Note 10 - Shareholders' Equity (Details Textual)

v3.21.2
Note 10 - Shareholders' Equity (Details Textual) - USD ($)
 3 Months Ended 6 Months Ended
Feb. 13, 2020
Mar. 31, 2021
Mar. 31, 2020
Jun. 30, 2021
Jun. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period (in shares)       40,000 7,200
Stock Issued During Period, Value, Stock Options Exercised   $ 244,000 $ 16,000 $ 244,000 $ 16,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value       $ 132,000  
Stock Issued During Period, Shares, Exercise of Common Stock Warrants (in shares)       0  
Stock Issued During Period, Shares, New Issues (in shares) 2,125,000        
Shares Issued, Price Per Share (in dollars per share) $ 4.00        
Proceeds from Issuance of Common Stock $ 8,500,000     $ 0 $ 7,682,000
Proceeds from Issuance of Common Stock, Net $ 7,700,000        
Warrants Issued in Private Placement [Member]          
Stock Issued During Period, Shares, Exercise of Common Stock Warrants (in shares)     0