Note 11 - Concentrations (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Accounts Receivable, after Allowance for Credit Loss, Current, Total	$ 1,278,000	$ 1,509,000
Revenue from Contract with Customer, Including Assessed Tax	$ 12,160,000	$ 9,003,000
Supplier Concentration Risk [Member] | Cost of Goods and Service Benchmark [Member] | Supplier 1 [Member]
Concentration Risk, Percentage	57.00%	43.00%
Supplier Concentration Risk [Member] | Cost of Goods and Service Benchmark [Member] | Supplier 2 [Member]
Concentration Risk, Percentage	18.00%	14.00%
Customer 1 [Member]
Accounts Receivable, after Allowance for Credit Loss, Current, Total	$ 337,000	$ 494,000
Revenue from Contract with Customer, Including Assessed Tax	$ 3,575,000	$ 2,120,000
Customer 1 [Member] | Customer Concentration Risk [Member] | Accounts Receivable [Member]
Concentration Risk, Percentage	26.00%	33.00%
Customer 1 [Member] | Customer Concentration Risk [Member] | Revenue Benchmark [Member]
Concentration Risk, Percentage	28.00%	22.00%
Distributor 1 [Member]
Accounts Receivable, after Allowance for Credit Loss, Current, Total	$ 177,000	$ 229,000
Revenue from Contract with Customer, Including Assessed Tax	$ 1,470,000	$ 861,000
Distributor 1 [Member] | Customer Concentration Risk [Member] | Accounts Receivable [Member]
Concentration Risk, Percentage	14.00%	15.00%
Distributor 1 [Member] | Customer Concentration Risk [Member] | Revenue Benchmark [Member]
Concentration Risk, Percentage	11.00%	9.00%
Distributor 2 [Member]
Accounts Receivable, after Allowance for Credit Loss, Current, Total	$ 170,000	$ 220,000
Distributor 2 [Member] | Customer Concentration Risk [Member] | Accounts Receivable [Member]
Concentration Risk, Percentage	13.00%	15.00%