Annual report pursuant to Section 13 and 15(d)

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

v3.19.1
Note 2 - Summary of Significant Accounting Policies (Details Textual)
12 Months Ended
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Jan. 01, 2018
USD ($)
Retained Earnings (Accumulated Deficit), Ending Balance $ (155,385,000) $ (105,581,000) $ (105,404,000)
Other Liabilities, Noncurrent, Total 634,000 327,000 132,000
Accrued Liabilities, Current, Total $ 6,766,000 4,605,000 4,623,000
Number of Financial Institutions 1    
Allowance for Doubtful Accounts Receivable, Ending Balance $ 284,000 221,000  
Inventory, Finished Goods, Net of Reserves 3,232,000 1,990,000  
Inventory, Raw Materials, Net of Reserves 887,000 40,000  
Contract with Customer, Asset, Net, Total 0 0  
Contract with Customer, Liability, Total 686,000 0  
Gross Profit, Total 7,320,000 $ 7,444,000  
Equity Method Investment, Other than Temporary Impairment $ 0    
Minimum [Member]      
Property, Plant and Equipment, Useful Life 3 years    
Warranty Period 1 year    
Maximum [Member]      
Property, Plant and Equipment, Useful Life 7 years    
Warranty Period 3 years    
Medical Equipment, Sales Demos [Member]      
Property, Plant and Equipment, Useful Life 5 years    
Customer Concentration Risk [Member] | Sales Revenue, Net [Member]      
Concentration Risk, Number of Customers 1 2  
Customer Concentration Risk [Member] | Sales Revenue, Net [Member] | One Customer [Member]      
Concentration Risk, Percentage 21.00%    
Customer Concentration Risk [Member] | Sales Revenue, Net [Member] | Two Customers [Member]      
Concentration Risk, Percentage   35.00%  
Customer Concentration Risk [Member] | Accounts Receivable [Member]      
Concentration Risk, Number of Customers 3 2  
Customer Concentration Risk [Member] | Accounts Receivable [Member] | Two Customers [Member]      
Concentration Risk, Percentage   57.00%  
Customer Concentration Risk [Member] | Accounts Receivable [Member] | Three Customers [Member]      
Concentration Risk, Percentage 54.00%    
Accounting Standards Update 2014-09 [Member]      
Retained Earnings (Accumulated Deficit), Ending Balance [1]     177,000
Other Liabilities, Noncurrent, Total [2]     (195,000)
Accrued Liabilities, Current, Total [3]     $ 18,000
Gross Profit, Total $ 749,000    
[1] Change relates to cumulative effect adjustment upon adoption of ASC 606.
[2] Change relates to long-term deferred revenue related to the extended warranties not required to be recorded under ASC 606.
[3] Change relates to future costs associated with extended warranties required to be recorded on adoption of ASC 606.