Quarterly report pursuant to Section 13 or 15(d)

Note 3 - Summary of Significant Accounting Policies (Details Textual)

v3.21.2
Note 3 - Summary of Significant Accounting Policies (Details Textual)
6 Months Ended
Apr. 27, 2020
USD ($)
Jun. 30, 2021
USD ($)
shares
Jun. 30, 2020
USD ($)
shares
Dec. 31, 2020
USD ($)
Number of Operating Segments   2    
Short-term Investments, Total   $ 14,800,000   $ 13,100,000
Accounts Receivable, Allowance for Credit Loss, Ending Balance   280,864   10,000
Inventory Valuation Reserves, Ending Balance   450,000   453,000
Proceeds from Notes Payable, Total   0 $ 272,099  
Unrecognized Tax Benefits, Ending Balance   0   $ 0
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense, Total   $ 0    
Open Tax Year   2017 2018 2019    
Options and Warrants [Member]        
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares) | shares   8,015,193 7,686,628  
Paycheck Protection Program CARES Act [Member]        
Proceeds from Notes Payable, Total $ 276,000      
Minimum [Member]        
Property, Plant and Equipment, Useful Life (Year)   2 years    
Maximum [Member]        
Property, Plant and Equipment, Useful Life (Year)   7 years