Note 8 - Geographic Segment Data - Net Sales to Outside Customers (Details) - USD ($)	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Net Sales	$ 6,325,241	$ 5,745,353	$ 13,741,409	$ 12,812,854
UNITED STATES
Net Sales	5,711,952	4,542,484	12,310,942	9,968,423
MEXICO
Net Sales	$ 613,289	$ 1,202,869	$ 1,430,467	$ 2,844,431

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