Share Capital - Stock Option Activity (Details) - shares		3 Months Ended		9 Months Ended		12 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Options Outstanding, Beginning balance		2,831,985	2,276,897	2,339,905	1,910,823	1,910,823
Number of Options, Granted		12,000	1,050	698,450	447,550
Number of Options, Exercised	[1]	(119,129)		(237,848)	(71,006)
Number of Options, Forfeited, cancelled or expired		(42,593)	(70,567)	(118,244)	(79,987)
Number of Options Outstanding, Ending balance		2,682,263	2,207,380	2,682,263	2,207,380	2,339,905
Number of Options Exercisable		1,471,329	1,417,660	1,471,329	1,417,660

[1] During the nine months ended September 30, 2018, 41,507 stock options were exercised for the same number of common shares for cash (nine months ended September 30, 2017 – 63,425). In the same period, the Company issued 103,189 common shares (nine months ended September 30, 2017 – 4,405) for the cashless exercise of 196,341 stock options (nine months ended September 30, 2017 – 7,581).