Share Capital - Summary of Non-Vested Stock Option Activity (Details)	12 Months Ended
	Dec. 31, 2017 $ / shares shares	Dec. 31, 2017 CAD / shares shares	Dec. 31, 2016 $ / shares shares	Dec. 31, 2016 CAD / shares shares	Dec. 31, 2015 $ / shares shares
Sharebased Compensation Arrangement By Sharebased Payment Award Options Nonvested Number Of Shares Roll Forward
Number of Options, Non-vested, Beginning balance	618,811	618,811
Number of Options, Granted	620,950	620,950	323,794	323,794	529,288
Number of Options, Vested	(274,580)	(274,580)
Number of Options, Forfeited and cancelled	(64,577)	(64,577)
Number of Options, Non-vested, Ending balance	900,604	900,604	618,811	618,811
Weighted Average Grant Date Fair Value, Non-vested, Beginning balance | (per share)	$ 7.13	CAD 9.58
Weighted Average Grant Date Fair Value, Granted | (per share)	5.02	6.51	$ 4.94		$ 9.83
Weighted Average Grant Date Fair Value, Vested | (per share)	7.45	9.68
Weighted Average Grant Date Fair Value, Forfeited and cancelled | (per share)	5.74	7.46
Weighted Average Grant Date Fair Value, Non-vested, Ending balance | (per share)	$ 5.66	CAD 7.12	$ 7.13	CAD 9.58