Note 4 - Reclassifications (Details Textual) - USD ($)	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Cost of Goods and Services Sold, Total	$ 1,386,948	$ 1,197,448	$ 4,142,616	$ 4,101,973
Revenue from Contract with Customer, Including Assessed Tax	$ 3,317,370	3,344,374	$ 9,777,086	10,666,525
Reclassified Certain Sales Rebates From Cost of Sales to Net Sales [Member]
Cost of Goods and Services Sold, Total		69,628		226,207
Revenue from Contract with Customer, Including Assessed Tax		$ (69,628)		$ (226,207)

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.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130545-203045

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130543-203045

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