Note 5 - Intangible Assets and Goodwill - Summary of Intangible Assets (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Gross Carrying Amount	$ 1,291,000	$ 1,310,000
Accumulated Amortization	1,116,000	1,095,000
Net	175,000	215,000
Gross Carrying Amount	2,434,000	2,453,000
Net	1,318,000	1,358,000	$ 1,467,000
In Process Techonology [Member]
Gross Carrying Amount	1,143,000	1,143,000
Net	$ 1,143,000	$ 1,143,000
Trade Names [Member]
Weighted Average Amortization Period (Year)	3 years	3 years
Gross Carrying Amount	$ 52,000	$ 52,000
Accumulated Amortization	$ 52,000	$ 52,000
Developed Technology Rights [Member]
Weighted Average Amortization Period (Year)	10 years	10 years
Gross Carrying Amount	$ 318,000	$ 318,000
Accumulated Amortization	143,000	111,000
Net	$ 175,000	$ 207,000
Licensing Agreements [Member]
Weighted Average Amortization Period (Year)	7 years	7 years
Gross Carrying Amount	$ 418,000	$ 432,000
Accumulated Amortization	$ 418,000	424,000
Net		$ 8,000
Device Registration [Member]
Weighted Average Amortization Period (Year)	7 years	7 years
Gross Carrying Amount	$ 78,000	$ 66,000
Accumulated Amortization	$ 78,000	$ 66,000
Customer Relationships [Member]
Weighted Average Amortization Period (Year)	3 years	3 years
Gross Carrying Amount	$ 425,000	$ 442,000
Accumulated Amortization	$ 425,000	$ 442,000