Note 10 - Concentration of Credit Risk - Concentration of Credit Risk, Net Sales (Details) - USD ($)	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Net Sales	$ 5,745,353	$ 9,202,406	$ 12,812,854	$ 17,882,423
Customer One [Member]
Net Sales	$ 2,508,000	$ 2,769,000	$ 5,675,000	$ 6,630,000
Customer One [Member] \| Customer Concentration Risk [Member] \| Revenue Benchmark [Member]
Percent of net sales	43.00%	30.00%	44.00%	37.00%

Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise.

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+ Details