Supplemental Disclosure of Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Supplemental disclosure of cash flow information:
Cash paid for interest	$ 42	$ 72	$ 93
Supplemental disclosure of non-cash financing and investing activities:
Non-cash property additions	150	425	$ 123
Accrued financing transaction costs	$ 17	$ 166