Quarterly report pursuant to Section 13 or 15(d)

Note 2 - Summary of Significant Accounting Policies (Details Textual)

v3.20.1
Note 2 - Summary of Significant Accounting Policies (Details Textual)
3 Months Ended 12 Months Ended
Sep. 18, 2019
USD ($)
Mar. 31, 2020
USD ($)
$ / shares
shares
Mar. 31, 2019
USD ($)
Dec. 31, 2019
USD ($)
$ / shares
shares
Nov. 30, 2019
shares
Payments for Fractional Shares of Reverse Stock Split $ 6,000        
Common Stock, Par or Stated Value Per Share (in dollars per share) | $ / shares   $ 0.0001   $ 0.0001 [1]  
Common Stock, Shares Authorized (in shares) | shares   75,000,000   75,000,000 [1]  
Number of Financial Institutions   1      
Accounts Receivable, Allowance for Credit Loss, Ending Balance   $ 481,000   $ 407,000  
Accounts Receivable, Allowance for Credit Loss, Writeoff   0 $ 0    
Deferred Income   703,000   662,000  
Contract with Customer, Liability, Revenue Recognized   297,000      
Contract with Customer, Asset, after Allowance for Credit Loss, Total   0   0  
Contract with Customer, Liability, Total   25,000   108,000  
Capitalized Contract Cost, Net, Total   211,000   337,000  
Capitalized Contract Cost, Impairment Loss   0 0    
Capitalized Contract Cost, Amortization   198,000 0    
Equity Method Investment, Other than Temporary Impairment   $ 0 $ 0    
Series A Preferred Stock [Member]          
Convertible Preferred Stock, Shares Issued upon Conversion (in shares) | shares   1     1
Series B Preferred Stock [Member]          
Conversion of Stock Exchange Ratio   653.59      
Preferred Stock, Liquidation Preference Per Share (in dollars per share) | $ / shares   $ 1,000      
Conversion of Stock, Conversion Rate (in dollars per share) | $ / shares   $ 1.53      
Minimum [Member]          
Warranty Period (Year)   1 year      
Maximum [Member]          
Warranty Period (Year)   3 years      
Marketing Programs [Member]          
Contract with Customer, Liability, Revenue Recognized   $ 83,000      
Contract with Customer, Liability, Total   $ 25,000   $ 108,000  
Customer Concentration Risk [Member] | Revenue Benchmark [Member]          
Concentration Risk, Number of Customers   1 3    
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | One Customer [Member]          
Concentration Risk, Percentage   48.00%      
Customer Concentration Risk [Member] | Revenue Benchmark [Member] | Three Customers [Member]          
Concentration Risk, Percentage     42.00%    
Customer Concentration Risk [Member] | Accounts Receivable [Member]          
Concentration Risk, Number of Customers   2   2  
Customer Concentration Risk [Member] | Accounts Receivable [Member] | Two Customers [Member]          
Concentration Risk, Percentage   49.00%   49.00%  
Reverse Stock Split [Member]          
Stockholders' Equity Note, Stock Split, Conversion Ratio 100        
[1] The condensed consolidated balance sheet as of December 31, 2019 has been derived from the audited consolidated financial statements as of that date.