Segment Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 3,878	$ 5,044
North America
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	3,389	4,057
Asia
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	478	942
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 11	$ 45