Geographical Information (Long-Lived Assets, Net By Geographic Region) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Long-lived assets, net	$ 4,428	$ 5,352
United States [Member]
Segment Reporting Information [Line Items]
Long-lived assets, net	1,464	2,063
United Kingdom [Member]
Segment Reporting Information [Line Items]
Long-lived assets, net	1,580	1,727
Other [Member]
Segment Reporting Information [Line Items]
Long-lived assets, net	$ 1,384	$ 1,562