Basis of Presentation (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Basis of Presentation [Abstract]
Perpetual technology license for wireless communication technologies purchased			$ 150	$ 0
Unrecognized compensation expense related to unvested stock options	$ 17		$ 17
Number of years to recognize remaining expense			3 years
Options excluded from the computations of diluted weighted-average shares outstanding	329,488	304,783	330,636	307,500

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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Amount of cost to be recognized for option under share-based payment arrangement.

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The cash outflow to acquire asset without physical form usually arising from contractual or other legal rights, excluding goodwill.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
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