Note 9 - Patents and Trademarks, Net - Weighted Average Amortization Periods (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Purchased and Licensed Patent Rights [Member]
Weighted average amortization periods (Year)	17 years	17 years
Internally Developed Patents [Member]
Weighted average amortization periods (Year)	17 years	17 years
Trademarks [Member]
Weighted average amortization periods (Year)	10 years	10 years