Stock Option Plan (Tables)

9 Months Ended

Sep. 30, 2015

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Schedule of Share-based Compensation, Stock Options, Activity

The following table presents stock option activity for the period:

	Three Months Ended September 30,						Nine Months Ended September 30,
	2015			2014			2015			2014
Outstanding, beginning of period		1,745,018			1,442,741			1,484,218			1,333,099
Granted		4,100			6,273			384,538			163,504
Exercised(1)		(110,039	)		(1,028	)		(209,850	)		(1,800	)
Forfeited and expired		(1,905	)		(4,411	)		(21,732	)		(51,228	)
Outstanding, end of period		1,637,174			1,443,575			1,637,174			1,443,575
Exercisable, end of period		1,052,955			1,078,009			1,052,955			1,078,009

⁽¹⁾ During the nine months ended September 30, 2015, 62,469 stock options were exercised for the same number of common shares for cash. In the same period, the Company issued 100,465 common shares for the cashless exercise of 147,381 stock options.

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions

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 September 30,						Nine Months Ended September 30,
	2015			2014			2015			2014
Average risk-free interest rate		1.74	%		1.95	%		1.71	%		1.97	%
Average expected term (in years)		6.25			6.25			6.23			6.20
Expected volatility		67	%		74	%		75	%		74	%
Expected dividend yield		0.00	%		0.00	%		0.00	%		0.00	%
Expected forfeiture rate		0.00	%		0.00	%		0.00	%		0.00	%