Stock Option Plan

3 Months Ended

Mar. 31, 2015

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock option plan

8. Stock option plan:

The following table presents stock option activity for the period:

	Three Months Ended March 31,
	2015			2014
Outstanding, beginning of period		1,484,218			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
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.

The fair value of each option issued to employees and non-employees is estimated using the Black-Scholes option-pricing model with the following weighted-average assumptions:

	Three Months Ended March 31,
	2015			2014
Average risk-free interest rate		1.71	%		1.97	%
Average expected term (in years)		6.25			6.20
Expected volatility		75	%		74	%
Expected dividend yield		0.00	%		0.00	%
Expected forfeiture rate		0.00	%		0.00	%

The weighted-average fair value of options granted during the three months ended March 31, 2015 was $11.84 (three months ended March 31, 2014 - $6.57) per option.