Basis of Presentation - Schedule of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Cash and cash equivalents	$ 1,366	$ 4,054	$ 7,496
Restricted cash - pledged deposits for performance bonds	3,668		3,668
Cash, cash equivalents and restricted cash shown in the statement of cash flows	$ 5,034	$ 7,722	$ 11,164	$ 7,296