Note 6 - Goodwill and Intangible Assets - Definite-lived Intangible Assets (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Net Carrying Amount	$ 11,000	$ 16,000	[1]
Patents and Trademarks [Member]
Weighted Average Amortization Period (Year)	3 years	3 years
Gross Carrying Amount	$ 474,000	$ 474,000
Accumulated Amortization	(463,000)	(458,000)
Net Carrying Amount	$ 11,000	$ 16,000

[1] The condensed consolidated balance sheet as of December 31, 2018 has been prepared using information from the audited consolidated balance sheet as of that date.