10. Additional Paid-in Capital

Warrants

Warrant activity is summarized in the following table:


	Warrants outstanding		Weighted average exercise price per share	Weighted average remaining life (yrs.)		Intrinsic value

As of December 31, 2012	19,977,743	$	4.25	2.6	$	-
As of December 31, 2013	19,977,743	$	4.63	1.6	$	-
Expired	(4,757,941)
As of December 31, 2014	15,219,802	$	5.00	0.8	$	-

The 15,219,802 outstanding warrants expire in October 2015. The exercise price for the 15,219,802 warrants is $5.00 per common share.

Compensation Options


	Compensation options outstanding		Weighted average exercise price per share	Expiry date	Weighted average remaining life (yrs.)

As of December 31, 2012	225,000	$	3.30	April 2013	0.3
Exercised	(225,000)
As of December 31, 2013	-
As of December 31, 2014	-

Stock-Based Compensation

Under our Stock Option Plan (the “Plan”) and our Long-Term Equity Incentive Plan (the “LTIP”), we may grant options and/or RSUs or restricted stock awards to our directors, officers, employees and consultants. The combined maximum number of our Common Shares that may be reserved for issuance under the Plan and the LTIP is a variable number equal to 10% of the issued and outstanding Common Shares on a non-diluted basis. Options and RSUs under the Plan and LTIP, respectively, are granted from time to time at the discretion of the Board, with vesting periods and other terms as determined by the Board. Stock-based compensation expense for the years ended December 31, 2014, 2013 and 2012 is as follows:


		Year ended December 31,
		2014		2013		2012

Stock options	$	160	$	370	$	1,081
Restricted stock units		966		372		3,144
	$	1,126	$	742	$	4,225

As of December 31, 2014, stock options and RSUs had unrecognized compensation expense of $26 and $879, respectively, which is expected to be recognized over a weighted average period of 3.99 and 1.36 years, respectively.

Stock Options

A summary of option activity under the Plan as of December 31, 2014 and 2013 and changes during the period then ended is set forth in the following table:


	Number of options		Weighted average exercise price per option	Weighted average remaining contractual term		Aggregate intrinsic value

Outstanding - December 31, 2012	3,102,500	$	2.80	2.68	$	637
Granted	985,000		0.36
Cancelled/Forfeited	(450,000)		3.07
Expired	(755,000)		3.32
Outstanding - December 31, 2013	2,882,500		1.79	3.07		54
Granted	175,000		0.52
Cancelled/Forfeited	(125,000)		3.16
Expired	(675,000)		1.85
Outstanding - December 31, 2014	2,257,500	$	1.60	3.02	$	-

Exercisable - December 31, 2014	2,011,250	$	1.75	2.90	$	-

A summary of our unvested stock options as of December 31, 2014 and 2013 and changes during the period then ended is set forth in the following table:


	Number of options		Weighted average grant-date fair value per option	Weighted average remaining amortization period (Years)

Unvested - December 31, 2012	300,000	$	1.47
Granted	985,000		0.22
Vested	(546,250)		0.90
Unvested - December 31, 2013	738,750		0.22
Granted	175,000		0.30
Vested	(667,500)		0.24
Unvested - December 31, 2014	246,250	$	0.22	3.99

The fair value of stock options granted to employees, directors and consultants was estimated at the grant date using the Black-Scholes option pricing model using the following assumptions:


		Years ended December 31,
	2014		2013	2012

Expected volatility	69.17%		72.26%	81.69%	-	83.67%
Risk-free interest rate	1.75%		1.70%	0.77%	-	0.88%
Expected life (years)	5		5	5
Dividend yield	N/A		N/A	N/A
Forfeiture rate	10%		15%	15%

Option pricing models require the input of highly subjective assumptions, including the expected price volatility. Expected price volatility is based on the historical volatility of our common shares. Changes in the subjective input assumptions can materially affect the fair value estimate. The expected term of the options granted represents the period of time that the options granted are expected to be outstanding. The risk-free rate for the periods within the contractual term of the option is based on the U.S. Treasury yield curve in effect at the date of grant.

Restricted Stock Units

The following table summarizes the RSU activity under the LTIP as of December 31, 2014 and 2013 and changes during the years then ended:


	Number of units		Weighted average grant-date fair value per RSU

Unvested - December 31, 2012	1,994,507	$	3.50
Cancelled	(1,133,592)		2.58
Vested	(116,875)		3.51
Granted	1,850,424		0.82
Unvested - December 31, 2013	2,594,464		2.00
Cancelled	(865,635)		3.42
Vested	(115,000)		3.84
Granted	2,079,000		0.46
Unvested - December 31 , 2014	3,692,829	$	0.74

A portion of the RSU awards vest on a fixed future date provided the recipient continues to be affiliated with Vista on that date. Other RSU awards vest subject to certain performance and market criteria, including the accomplishment of certain corporate objectives and the Company’s share price performance. The vesting period for RSUs is at least one year. The average forfeiture is approximately 29%, based on historical market conditions.