Note 3 - Patents, Net (Tables)

12 Months Ended

Dec. 31, 2018

Notes Tables

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

	2018			2017
Patents	$	228,669		$	338,324
Less: accumulated amortization		(82,213	)		(155,938	)
Patents, net	$	146,456		$	182,386

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

2019		11,582
2020		11,494
2021		9,838
2022		9,434
Thereafter		104,108
Total expense	$	146,456