STOCK-BASED COMPENSATION

At the Company's annual general meeting held on June 1, 2015, our shareholders voted for the approval of the 2015 Stock Incentive Plan (the "2015 Plan"). Under the 2015 Plan, 6,000,000 shares have been authorized for grants of stock options, restricted stock units ("RSUs"), restricted stock and stock appreciation rights to employees and non-employee directors. In addition, any shares available under the Amended and Restated Stock Incentive Plan (which expired on June 1, 2015), including in respect of any awards that expire, terminate or are forfeited, will be available for awards under the 2015 Plan. Under the 2015 Plan, awards are made to employees and to directors at the discretion of the Compensation Committee. Any awards previously issued under the Amended and Restated Stock Incentive Plan will continue to be governed by the terms of that plan.

The charge for stock-based compensation in our consolidated statements of operations and comprehensive income was as follows:



	For The Year Ending December 31,
	2015		2014		2013
Selling, general and administrative expenses	$	2,439	$	1,344	$	4,197
Restructuring costs (Note 15)	—		—		1,919
Total stock-based compensation charge	$	2,439	$	1,344	$	6,116

Stock Options

Grants of options allow the holders to purchase shares of Class A common stock at an exercise price, which is generally the market price prevailing at the date of the grant, with vesting between one and four years after the awards are granted. A summary of option activity for the year ended December 31, 2015 is presented below:



	Shares		Weighted Average Exercise Price per Share		Weighted Average Remaining Contractual Term (years)	Aggregate Intrinsic Value
Outstanding at December 31, 2014	155,000		$	29.88	0.92	$	—
Granted	1,600,000		2.29
Forfeited	(20,000	)	23.12
Expired	(69,000	)	28.23
Outstanding at December 31, 2015	1,666,000		$	3.53	9.07	$	640
Vested or expected to vest	1,666,000		3.53		9.07	640
Exercisable at December 31, 2015	66,000		$	33.66	0.42	$	—

When options are vested, holders may exercise them at any time up to the maximum contractual life of the instrument which is specified in the option agreement. At December 31, 2015, the maximum life of options that had been issued under the Plan was ten years. Upon providing the appropriate written notification, holders pay the exercise price and receive shares. Shares delivered in respect of stock option exercises are newly issued shares.

The fair value of stock options is estimated on the grant date using the Black-Scholes option-pricing model and recognized ratably over the requisite service period as a component of selling, general and administrative expenses. The weighted average grant date fair value of stock options granted during 2015 was $1.54 per option.

The aggregate intrinsic value (the difference between the stock price on the last day of trading of the fourth quarter of 2015 and the exercise prices multiplied by the number of in-the-money options) represents the total intrinsic value that would have been received by the option holders had they exercised all in-the-money options as at December 31, 2015. This amount changes based on the fair value of our Class A common stock.

The weighted average assumptions used in the Black-Scholes model for grants made in the year ending December 31, 2015 were as follows:



	For The Year Ending December 31, 2015
Risk-free interest rate	1.86		%
Expected term (years)	6.25
Expected volatility	75.18		%
Dividend yield	0		%
Weighted-average fair value	$	1.54

As at December 31, 2015, there was US$ 2.1 million unrecognized compensation expense related to stock options which is expected to be recognized over a weighted-average period of 3.4 years.

The following table summarizes information about stock option activity during 2015, 2014, and 2013:



	2015			2014				2013
	Shares	Weighted Average Exercise Price (per share)		Shares		Weighted Average Exercise Price (per share)		Shares		Weighted Average Exercise Price (per share)
Outstanding at January 1	155,000	$	29.88	390,500		$	27.26	2,219,625		$	31.51
Awards granted	1,600,000	2.29		—		—		—		—
Awards exchanged ⁽¹⁾	—	—		—		—		(1,618,000	)	31.54
Awards forfeited	(20,000)	23.12		(114,500	)	30.87		(136,125	)	33.36
Awards expired	(69,000)	28.23		(121,000	)	20.48		(75,000	)	49.71
Outstanding at December 31	1,666,000	$	3.53	155,000		$	29.88	390,500		$	27.26


⁽¹⁾	Options tendered in exchange for restricted stock units pursuant to an employee option exchange program completed in 2013.

Restricted Stock Units

Each RSU represents a right to receive one share of Class A common stock of the Company for each RSU that vests in accordance with a time-based vesting schedule, generally between one to four years from the date of grant. Upon vesting, shares of Class A common stock are issued from authorized but unissued shares. Holders of RSU awards are not entitled to receive cash dividend equivalents and are not entitled to vote. The grant date fair value of RSUs is calculated as the closing price of our Class A common shares on the date of grant. For awards with market conditions, the grant date fair value is calculated using a Monte Carlo simulation model. The Monte Carlo simulation model requires the input of subjective assumptions, including the expected volatility of our common stock, interest rates, dividend yields and correlation coefficient between our common stock and the relevant market index.

The following table summarizes information about unvested RSUs as at December 31, 2015:



	Number of Shares / Units		Weighted-Average Grant Date Fair Value
Unvested at December 31, 2014	1,367,234		$	3.06
Granted	1,661,430		2.56
Vested	(465,136	)	3.16
Forfeited	(8,931	)	3.85
Unvested at December 31, 2015	2,554,597		$	2.72

As at December 31, 2015, the intrinsic value of unvested RSUs was US$ 6.9 million. Total unrecognized compensation cost related to unvested RSUs as at December 31, 2015 was US$ 3.8 million and is expected to be recognized over a weighted-average period of 2.7 years.