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Segment Information (Details) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2018 USD ($) | Sep. 30, 2017 USD ($) | Sep. 30, 2018 USD ($) segment | Sep. 30, 2017 USD ($)
Segment Reporting Information [Line Items] |  |  |  |
Number of operating segments | segment |  |  | 1 |
Revenue | $ 16,396 | $ 15,913 | $ 49,318 | $ 51,033
Operating costs and corporate expenses | 16,440 | 15,320 | 48,786 | 49,683
Total other income (expense), net | 180 | (14) | 179 | (12)
Income before provision for income taxes | 136 | 579 | 711 | 1,338
Corporate |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenue | 0 | 0 | 0 | 0
Operating costs and corporate expenses | 7,889 | 7,660 | 23,055 | 23,734
Total other income (expense), net | 180 | (14) | 179 | (12)
Income before provision for income taxes | (7,709) | (7,674) | (22,876) | (23,746)
Rental |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenue | 12,039 | 11,292 | 34,937 | 34,634
Operating costs and corporate expenses | 5,363 | 4,333 | 15,262 | 13,256
Total other income (expense), net | 0 | 0 | 0 | 0
Income before provision for income taxes | 6,676 | 6,959 | 19,675 | 21,378
Sales |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenue | 3,947 | 4,256 | 13,328 | 15,300
Operating costs and corporate expenses | 3,081 | 3,237 | 10,196 | 12,405
Total other income (expense), net | 0 | 0 | 0 | 0
Income before provision for income taxes | 866 | 1,019 | 3,132 | 2,895
Service & Maintenance |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Revenue | 410 | 365 | 1,053 | 1,099
Operating costs and corporate expenses | 107 | 90 | 273 | 288
Total other income (expense), net | 0 | 0 | 0 | 0
Income before provision for income taxes | $ 303 | $ 275 | $ 780 | $ 811

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