Income Taxes - Net Deferred Income Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deferred income tax assets
Investment tax credits	$ 21,303	$ 20,108
Scientific research and experimental development pool	21,088	19,648
Non-capital losses	4,234	1,390
Depreciable assets	3,749	2,651
Deferred financing fees	959	1,318
Deferred revenues	41	3,063
Other	144	858
Less - valuation allowance	$ (51,518)	$ (49,036)