Note 6 - Goodwill and 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
	Weighted Average Amortization Period (Years)		Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount		Weighted Average Amortization Period (Years)		Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount
Patents and Trademarks		3.0	$	474,000	$	(467,000	)	$	7,000		3.0	$	474,000	$	(463,000	)	$	11,000

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

2021		3,000
2022		2,000
2023		1,000
2024		1,000
Total	$	7,000