Note 6 - Goodwill and Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2017

Notes Tables

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

	December 31, 2017									December 31, 2016
	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		4.0	$	474,000	$	(453,000	)	$	21,000		4.0	$	474,000	$	(440,000	)	$	34,000

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

Years ending December 31,
2018	$	5,000
2019		3,000
2020		3,000
2021		2,000
2022		2,000
Thereafter		6,000
	$	21,000