Stock Option Plan

6 Months Ended

Jun. 30, 2016

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock option plan

7. Stock option plan:

The following table presents stock option activity for the period:

	Three Months Ended June 30,						Six Months Ended June 30,
	2016			2015			2016			2015
Outstanding, beginning of period		1,934,734			1,785,436			1,721,472			1,484,218
Granted		65,450			33,474			299,400			380,438
Exercised(1)		(14,283	)		(55,155	)		(30,529	)		(99,811	)
Forfeited and expired		(2,227	)		(18,737	)		(6,669	)		(19,827	)
Outstanding, end of period		1,983,674			1,745,018			1,983,674			1,745,018
Exercisable, end of period		1,195,883			1,126,629			1,195,883			1,126,629

⁽¹⁾ During the six months ended June 30, 2016, 29,270 stock options were exercised for the same number of common shares for cash (six months ended June 30, 2015 – 53,442). In the same period, the Company issued 741 common shares (six months ended June 30, 2015 – 32,399) for the cashless exercise of 1,259 stock options (six months ended June 30, 2015 – 46,369).

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 June 30,						Six Months Ended June 30,
	2016			2015			2016			2015
Average risk-free interest rate		1.44	%		1.71	%		1.60	%		1.71	%
Average expected term (in years)		6.14			6.04			6.23			6.23
Expected volatility		74	%		75	%		75	%		75	%
Expected dividend yield		0.00	%		0.00	%		0.00	%		0.00	%

The weighted-average fair value of options granted during the six months ended June 30, 2016 was $4.90 (six months ended June 30, 2015 – $11.96) per option.