Federal Income Taxes - Schedule of Reconciliation of Expected Income Tax on Net Income at Statutory Rates (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Net loss	$ (19,288)	$ (19,605)
Statutory tax rate	34.00%	34.00%
Tax recovery at statutory rate	$ (6,558)	$ (6,666)
Foreign tax rate	71	2,073
Change in US tax rates	37,233
Mineral property adjustments		(6,709)
Capital loss carryforward adjustment	(44)
Operating loss carryforward adjustment	710	6,707
Nondeductible write-offs	15	1,250
Change in valuation allowance	(31,427)	3,345
Income tax expense (recovery)