Note 3 - Patents, Net (Tables)

12 Months Ended

Dec. 31, 2017

Notes Tables

Schedule of Finite-Lived Intangible Assets [Table Text Block]

	2017			2016
Patents	$	338,324		$	289,228
Less: accumulated amortization		(155,938	)		(133,165	)
Patents, net	$	182,386		$	72,105

Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]

2018	$	21,207
2019		15,669
2020		13,223
2021		10,151
2022		9,626
Thereafter		112,510
Total expense	$	182,386