Stock Option Plan - Stock Option Activity (Details) - shares		3 Months Ended		12 Months Ended
		Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Outstanding, beginning of period		1,484,218	1,333,099	1,333,099
Granted		346,964	157,231
Exercised	[1]	(44,656)	(772)
Forfeited and expired		(1,090)	(44,238)
Outstanding, end of period		1,785,436	1,445,320	1,484,218
Exercisable, end of period		1,146,383	999,089

[1] During the three months ended March 31, 2015, 26,910 stock options were exercised for the same number of common shares for cash. In the same period, the Company issued 14,032 common shares for the cashless exercise of 17,746 stock options.