Domestic and Foreign Revenues - Significant Foreign Revenues from Operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Entity Wide Revenue Major Customer [Line Items]
Revenues from operations	$ 8,071	$ 8,588	$ 23,748	$ 23,058
Malaysia [Member]
Entity Wide Revenue Major Customer [Line Items]
Revenues from operations	722	1,109	2,303	2,788
Hong Kong [Member]
Entity Wide Revenue Major Customer [Line Items]
Revenues from operations	213	234	824	668
Australia [Member]
Entity Wide Revenue Major Customer [Line Items]
Revenues from operations	162	1	655	13
All other foreign countries [Member]
Entity Wide Revenue Major Customer [Line Items]
Revenues from operations	369	872	1,777	2,261
Foreign [Member]
Entity Wide Revenue Major Customer [Line Items]
Revenues from operations	1,466	2,216	5,559	5,730
Domestic [Member]
Entity Wide Revenue Major Customer [Line Items]
Revenues from operations	$ 6,605	$ 6,372	$ 18,189	$ 17,328