Property, Plant and Equipment (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Property, plant and equipment      
Property, plant, and equipment, gross $ 27,272 $ 42,002  
Less: accumulated depreciation (14,403) (31,588)  
Property, plant, and equipment, net 12,869 10,414  
Depreciation expense 2,600 1,900 $ 1,800
Land      
Property, plant and equipment      
Property, plant, and equipment, gross   90  
Buildings      
Property, plant and equipment      
Property, plant, and equipment, gross   15,332  
Building improvements      
Property, plant and equipment      
Property, plant, and equipment, gross 214 5,230  
Software, machinery and equipment      
Property, plant and equipment      
Property, plant, and equipment, gross $ 27,058 $ 21,350