Domestic and Foreign Revenues - Significant Foreign Revenues from Operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Entity Wide Revenue Major Customer [Line Items]
Revenues from operations	$ 6,632	$ 5,945
Malaysia [Member]
Entity Wide Revenue Major Customer [Line Items]
Revenues from operations	825	695
Hong Kong [Member]
Entity Wide Revenue Major Customer [Line Items]
Revenues from operations	267	105
All other foreign countries [Member]
Entity Wide Revenue Major Customer [Line Items]
Revenues from operations	617	634
Foreign [Member]
Entity Wide Revenue Major Customer [Line Items]
Revenues from operations	1,709	1,434
Domestic [Member]
Entity Wide Revenue Major Customer [Line Items]
Revenues from operations	$ 4,923	$ 4,511