Domestic and Foreign Revenues - Significant Foreign Revenues from Operations (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Entity Wide Revenue Major Customer [Line Items]
Revenues from operations	$ 7,838	$ 6,157	$ 14,470	$ 12,102
Malaysia [Member]
Entity Wide Revenue Major Customer [Line Items]
Revenues from operations	854	772	1,679	1,467
Hong Kong [Member]
Entity Wide Revenue Major Customer [Line Items]
Revenues from operations	167	128	434	233
All other foreign countries [Member]
Entity Wide Revenue Major Customer [Line Items]
Revenues from operations	784	647	1,401	1,281
Foreign [Member]
Entity Wide Revenue Major Customer [Line Items]
Revenues from operations	1,805	1,547	3,514	2,981
Domestic [Member]
Entity Wide Revenue Major Customer [Line Items]
Revenues from operations	$ 6,033	$ 4,610	$ 10,956	$ 9,121