Note 1 - Accounting Policies - Summary of Geographic Area Data (Details) - USD ($)		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Net sales to external customers		$ 10,003,239	$ 12,777,782
UNITED STATES
Net sales to external customers		7,670,061	10,258,939
Australia, New Zealand [Member]
Net sales to external customers		231,928	259,427
CANADA
Net sales to external customers		242,120	264,303
MEXICO
Net sales to external customers		107,371	157,317
Europe [Member]
Net sales to external customers	[1]	1,164,884	1,200,774
Asia [Member]
Net sales to external customers	[2]	$ 586,875	$ 637,022

[1] Europe consists of United Kingdom, Ireland, France, Germany, Austria, and the Netherlands.

[2] Asia consists of Philippines, Malaysia, Singapore, and Indonesia.