Property, Plant and Equipment (Details) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Property, plant and equipment | |||
| Property, plant, and equipment, gross | $ 37,912 | $ 35,225 | |
| Less: accumulated depreciation | (29,666) | (27,970) | |
| Property, plant, and equipment, net | 8,246 | 7,255 | |
| Depreciation expense | 1,800 | 1,500 | $ 1,400 |
| Land. | |||
| Property, plant and equipment | |||
| Property, plant, and equipment, gross | 90 | 90 | |
| Buildings. | |||
| Property, plant and equipment | |||
| Property, plant, and equipment, gross | 15,332 | 15,332 | |
| Building improvements | |||
| Property, plant and equipment | |||
| Property, plant, and equipment, gross | 5,221 | 5,169 | |
| Software, machinery and equipment | |||
| Property, plant and equipment | |||
| Property, plant, and equipment, gross | $ 17,269 | $ 14,634 | |