Share Capital - Stock Option Activity (Details) - shares		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Options Outstanding, Beginning balance		2,671,906	2,339,905
Number of Options, Granted		21,900	563,700
Number of Options, Exercised	[1]	(22,402)	(84,668)
Number of Options, Forfeited, cancelled or expired		(3,955)	(22,996)
Number of Options Outstanding, Ending balance		2,667,449	2,795,941
Number of Options Exercisable		1,769,984	1,505,459

[1] During the three months ended March 31, 2019, 20,576 stock options were exercised for the same number of common shares for cash (three months ended March 31, 2018 – 13,374). In the same period, the Company issued 657 common shares (three months ended March 31, 2018 – 27,507) for the cashless exercise of 1,826 stock options (three months ended March 31, 2018 – 71,294).