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Inventory (Narrative) (Details) $ in Thousands | 3 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Dec. 31, 2019 USD ($) | Sep. 30, 2019 USD ($) | Dec. 31, 2019 USD ($) | Dec. 31, 2018 USD ($) compressor | Dec. 31, 2017 USD ($) | Dec. 31, 2016 USD ($)
Inventory Disclosure [Abstract] |  |  |  |  |  |
Allowance for inventory obsolescence | $ 24 |  | $ 24 | $ 19 | $ 15 | $ 15
Available-for-sale or rental, compressor units | compressor |  |  |  | 7 |  |
Available-for-sale or rental, finished goods |  |  |  | $ 1,000 |  |
Inventory allowance | $ 408 | $ 3,400 | $ 3,758 | $ 0 | $ 273 |

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