Intangible Assets (Schedule Of Intangible Assets) (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 2,293	$ 2,264
Accumulated Amortization	(1,942)	(1,889)
Net	351	375
Patents
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	2,001	1,972
Accumulated Amortization	(1,665)	(1,614)
Net	336	358
Software
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	206	206
Accumulated Amortization	(206)	(206)
Net	0	0
Marketing assets and customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	86	86
Accumulated Amortization	(71)	(69)
Net	$ 15	$ 17