Share-based Compensation (Tables)

Weighted-average grant-date fair values of stock options and the assumptions used in estimating the fair values are as follows:



	Year Ended December 31,
	2015			2014			2013
Weighted-average grant-date fair value per share	$	19.04		$	56.15		$	41.52
Expected term (years)	5.60			6.25			6.25
Risk-free interest rate	1.70		%	1.00		%	1.00		%
Expected volatility	61.54		%	63.73		%	66.80		%

The following table summarizes the Company’s stock option activity:



	December 31, 2015
	Number of Shares		Weighted-average Exercise Price		Aggregate Intrinsic Value		Weighted- average Remaining Contractual Term
Outstanding at beginning of year	552		$	42.92
Granted	221		34.27
Exercised	(41	)	12.58
Forfeited	(34	)	52.43
Outstanding at end of year	698		$	41.52	$	542	6.2 years
Vested and expected to vest at end of year	690		$	41.50	$	542	6.1 years
Exercisable at end of year	391		$	35.88	$	542	4.4 years

The following table summarizes the Company’s unvested restricted stock and RSUs activity:



	December 31, 2015
	Number of Shares		Weighted-Average Grant-Date Fair Value
Unvested at beginning of year	88		$	77.94
Granted	117		34.15
Forfeited	(51	)	55.62
Vested	(9	)	70.04
Unvested at end of year	145		$	46.40

The following table summarizes the Company’s performance units activity:



	December 31, 2015
	Number of Shares		Weighted-Average Grant-Date Fair Value
Unvested at beginning of year	51		$	72.57
Granted	23		28.25
Vested	(15	)	55.93
Unvested at end of year	59		$	59.15

The following table summarizes the Company’s leveraged restricted share unit awards activity:



	December 31, 2015
	Number of Shares		Weighted-average Grant-Date Fair Value
Unvested at beginning of year	59		$	84.85
Vested	(18	)	67.05
Unvested at end of year	41		$	92.66