Business Segment, Geographic and Major Customer Information - Geographic Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Revenues from External Customers and Long-Lived Assets
Revenue	$ 11,770	$ 19,416
U.S.
Revenues from External Customers and Long-Lived Assets
Revenue	9,661	15,775
UAE
Revenues from External Customers and Long-Lived Assets
Revenue	1,103	1,461
Other countries
Revenues from External Customers and Long-Lived Assets
Revenue	$ 1,006	$ 2,180