Note 10 - Concentration of Credit Risk - Concentration of Credit Risk, Net Sales (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Net Sales	$ 6,234,231	$ 5,980,766	$ 19,975,640	$ 18,793,620
Customer One [Member]
Net Sales	$ 3,304,000	$ 3,737,000	$ 10,648,000	$ 8,190,000
Customer One [Member] | Customer Concentration Risk [Member] | Revenue Benchmark [Member]
Percent of net sales	53.00%	63.00%	53.00%	44.00%
Customer Two [Member]
Net Sales	$ 617,000	$ 0	$ 2,384,000	$ 2,912,000
Customer Two [Member] | Customer Concentration Risk [Member] | Revenue Benchmark [Member]
Percent of net sales	10.00%	0.00%	12.00%	16.00%