Note 18 - Geographic Segment Data - Financial Information By Geographic Area (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Sales to outside customers	$ 56,236,560	$ 64,268,367
Total Assets	39,984,038	43,913,739
UNITED STATES
Sales to outside customers	41,165,000	51,792,000
Total Assets	27,784,000	33,108,000
UNITED KINGDOM
Sales to outside customers	1,908,000	2,427,000
Total Assets	923,000	1,324,000
Europe [Member]
Sales to outside customers	4,142,000	2,590,000
Total Assets	2,989,000	2,418,000
MEXICO
Sales to outside customers	9,022,000	7,459,000
Total Assets	$ 8,288,000	$ 7,064,000