Income Taxes - Income Tax (Recovery) Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Computed taxes (recoveries) at Canadian federal and provincial tax rates	$ (5,980)	$ (4,095)	$ 3,385
Change in valuation allowance	6,897	2,482	(2,364)
Investment tax credits earned	(1,500)	(1,220)	(1,283)
Tax attributes expired/utilized	617	2,851	2,011
Non-deductible expenditures	569	977	(1,053)
Financing fees in equity	(531)		(1,945)
Other	$ (72)	$ (995)	$ 1,249