Six months ended June 30, 2018								Six months ended June 30, 2017
			Number of Options				Weighted average exercise price				Number of Options				Weighted average exercise price
Outstanding, Beginning of period			2,344			$	3.46				2,005			$	4.31
Granted			2,084				2.96				728				1.10
Exercised			(77	)			2.31				-				-
Forfeited			(17	)			2.01				(142	)			3.65
Expired			-				-				(263	)			4.97
Outstanding, end of period			4,334			$	3.16				2,328				3.40

 

 

							Options outstanding								Options exercisable
Range of exercise prices			Options				Weighted average remaining contractual life (years)				Weighted average exercise price				Options				Weighted average exercise price
$1.03-$2.66			824				8.5			$	1.26				401			$	1.28
$2.67-$2.85			790				9.6				2.78				790				2.78
$2.86-$3.00			359				7.9				2.91				184				2.91
$3.01-$3.97			1,165				9.5				3.09				28				3.70
$3.98-$32.88			1,196				6.1				4.87				1,158				4.86
			4,334				8.2			$	3.16				2,561			$	3.51

The following table presents the weighted average assumptions that were used in the Black-Scholes option pricing model to determine the fair value of stock options granted during the period, and the resultant weighted average fair values:

 

			Six months ended June 30, 2018				Six months ended June 30, 2017
Weighted average risk-free interest rate			2.39	%			1.24	%
Expected dividend yield			—				—
Weighted average expected volatility			93.9	%			100.2	%
Weighted average expected life of options (in years)			5				5
Weighted average grant date fair value		$	2.14			$	0.81

 

The Company uses historical data to estimate the expected dividend yield and expected volatility of its common shares in determining the fair value of stock options. The expected life of the options represents the estimated length of time the options are expected to remain outstanding.

 

Stock options granted by the Company during the months ended vest after year and on each of the next anniversaries, except for options which vest after year and on each of the next anniversaries and options which vested immediately on the grant date. During the - and -month periods ending the Company recorded share-based payment expense of thousand ( - thousand) and million (- thousand, respectively, related to issued stock options.

Refer to note for a breakdown of stock-based compensation expense by function related to both issued stock options and restricted share units.

 

The Company has available up to common shares for issuance relating to outstanding options, rights and other entitlements under the stock-based compensation plans of the Company as of

The Company has a stock incentive plan (SIP) pursuant to which the Board grant stock-based awards comprised of restricted stock units or dividend equivalents to employees, officers, consultants, independent contractors, advisors and non-employee directors of the Corporation or any affiliate. Each restricted unit is automatically redeemed for common share of the Company upon vesting. The following table presents the activity under the SIP plan for the months ended and the units outstanding.

 

		Six months ended, June 30, 2018								Six months ended, June 30, 2017
			Number (in thousands)				Weighted average grant date fair value				Number (in thousands)				Weighted average grant date fair value
Outstanding, beginning of period			-			$	-				-			$	-
Granted			-				-				150				1.14
Redeemed			-				-				(150	)			1.14
Outstanding, end of period			-			$	-				-			$	-

On the Company granted restricted share units with a vesting term of months. During the month and -month period ending the Company recorded share-based payment expense of (- thousand) and ( - thousand), respectively, related to the issued RSUs.

 

The grant date fair value was determined as the closing value of the common shares of the Company on the Toronto Stock Exchange on the date prior to the date of grant.