Income Taxes - (Provision) Benefit for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current (provision) benefit:
Current (provision) benefit income tax expense	$ (530)	$ (414)	$ 0
Deferred (provision):
Deferred (provision)	(53)	(51)	(22)
(Provision) for income taxes	(583)	(465)	(22)
Domestic | Canada
Current (provision) benefit:
Canada	(3)	105	0
Deferred (provision):
Canada	0	0	(22)
Foreign | U.S.
Current (provision) benefit:
U.S. and Other Foreign	106	(2)	0
Foreign | Other Foreign
Current (provision) benefit:
U.S. and Other Foreign	(633)	(517)	0
Deferred (provision):
U.S. and Other Foreign	$ (53)	$ (51)	$ 0