6. ADDITIONAL PAID-IN CAPITAL (Tables)

6 Months Ended

Jun. 30, 2015

Additional Paid in Capital [Abstract]

Fair value assumptions

	June 30,
	2015	2014
Risk-free interest rate	1.0% - 1.1%	0.93% - 0.99%
Expected volatility	73.4% - 79.7%	74.7% - 79.1%
Expected dividend yield	Nil	Nil
Expected term in years	3.4	3.25 – 3.28
Estimated forfeiture rate	3.4% - 3.6%	3.7%

Stock option activity

	2015		2014
	Number of Stock Options	Weighted Average Exercise Price	Number of Stock Options	Weighted Average Exercise Price
Outstanding, beginning of period	4,345,500	$      5.16	4,700,500	$      5.51
Granted	999,000	0.45	275,000	1.28
Cancelled/expired	(749,600)	3.16	(280,000)	6.74
Exercised	(6,000)	0.32	(150,000)	0.52
Outstanding, end of period	4,588,900	$      4.25	4,545,500	$      5.31
Exercisable, end of period	3,593,700	$      5.28	3,852,500	$      6.01
Weighted-average fair value per share of options granted during period	$                0.24		$                0.65