Other Financial Statement Data (Schedule Of Intangible Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 2,264	$ 2,139
Accumulated Amortization	(1,889)	(1,814)
Net	375	325
Patents [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,972	1,832
Accumulated Amortization	(1,614)	(1,542)
Net	358	290
Software [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	206	206
Accumulated Amortization	(206)	(200)
Net	0	6
Marketing Assets and Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	86	101
Accumulated Amortization	(69)	(72)
Net	$ 17	$ 29