Note 3 - Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2020

Notes Tables

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

	December 31, 2020					December 31, 2019
	Gross Carrying		Accumulated			Gross Carrying		Accumulated
	Amount		Amortization			Amount		Amortization
Amortized intangible assets:
Patents	$	450,982	$	(207,399	)	$	452,978	$	(181,609	)

	2020		2019
Aggregate amortization expense:
For the years ended December 31	$	25,790	$	31,869

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

2021	$	25,000
2022		25,000
2023		25,000
2024		24,000
2025		24,000
Thereafter		67,000