Domestic and Foreign Revenues - Significant Foreign Revenues from Operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Entity Wide Revenue Major Customer [Line Items]
Revenues from operations	$ 6,536	$ 8,618
Malaysia [Member]
Entity Wide Revenue Major Customer [Line Items]
Revenues from operations	609	1,018
Hong Kong [Member]
Entity Wide Revenue Major Customer [Line Items]
Revenues from operations	189	246
All other foreign countries [Member]
Entity Wide Revenue Major Customer [Line Items]
Revenues from operations	550	822
Foreign [Member]
Entity Wide Revenue Major Customer [Line Items]
Revenues from operations	1,348	2,086
Domestic [Member]
Entity Wide Revenue Major Customer [Line Items]
Revenues from operations	$ 5,188	$ 6,532