Stock Option Plan - Stock Option Activity (Details) - shares		3 Months Ended		12 Months Ended
		Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Outstanding, beginning of period		1,721,472	1,484,218	1,484,218
Granted		233,950	346,964
Exercised	[1]	(16,246)	(44,656)
Forfeited and expired		(4,442)	(1,090)
Outstanding, end of period		1,934,734	1,785,436	1,721,472
Exercisable, end of period		1,151,853	1,146,383

[1] During the three months ended March 31, 2016, 16,246 stock options were exercised for the same number of common shares for cash (three months ended March 31, 2015 – 26,910). In the same period, the Company did not issue any common shares (three months ended March 31, 2015 – 14,032) for the cashless exercise of stock options (three months ended March 31, 2015 – 17,746).