Stock-Based Compensation

12 Months Ended

Dec. 31, 2013

Stock-Based Compensation [Abstract]

Stock-Based Compensation

Note 6 - Stock-Based Compensation

The following tables summarize information about stock-options and RSU's outstanding at December 31, 2013:

Options Outstanding									Options Vested and Exercisable
Date of Option Issue	Range of Exercise Prices		Number Outstanding		Weighted Average Remaining Contractual Life (Years)		Weighted Average Exercise Price		Number Exercisable		Weighted Average Remaining Contractual Life (Years)		Weighted Average Exercise Price
2006	$	0.24		690,612		2.22	$	0.24		690,612		2.22	$	0.24
2007	$	4.20		1,277,574		3.56		4.20		1,277,574		3.56		4.20
2007	$	5.88-6.47		563,931		3.99		5.88		563,931		3.99		5.88
2008	$	1.74-6.20		169,500		4.37		5.13		169,500		4.37		5.13
2009	$	1.15- 1.58		933,211		5.26		1.16		933,211		5.26		1.16
2010	$	5.48-6.03		279,896		6.17		5.49		268,440		6.17		5.49
2011	$	19.85-23.62		425,000		7.37		23.62		290,416		7.37		23.62
2012	$	23.84 – 35.25		362,500		8.39		27.00		164,166		8.35		27.16
2013	$	23.72 – 35.05		274,625		9.37		25.37		52,561		9.36		25.70
				4,976,849		4.91	$	7.86		4,410,411		4.45	$	5.66

	RSU's Outstanding
Grant Date	Range of Grant Prices			Number Outstanding		Weighted Average Grant Price
2012		$	24.75 – 29.90		92,500		$	24.75
2013		$	23.72		156,415			23.72
					248,915		$	24.10

The following tables summarize activity under the Plan for the indicated periods:

	Options
	Number of Shares			Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (Years)		Aggregate Intrinsic Value
Outstanding at December 31, 2010		4,830,391		$	3.14		—		—
Options granted		475,000			23.80		—		—
Options exercised		(398,393	)		2.68		—		—
Options cancelled		—			—		—		—
Outstanding at December 31, 2011		4,906,998			5.12		—		—
Options granted		367,500			26.97		—		—
Options exercised		(486,165	)		3.48		—		—
Options cancelled		(12,109	)		17.34		—		—
Outstanding at December 31, 2012		4,776,224			6.94		—		—
Options granted		274,625			25.37		—		—
Options exercised		(39,833	)		4.27		—		—
Options cancelled		(34,167	)		20.57		—		—
Outstanding at December 31, 2013		4,976,849		$	7.86		4.91	$	63,649

	RSU's
	Number of RSU's			Weighted Average Grant Date Fair Value		Aggregate Intrinsic Value
Outstanding at December 31, 2011		—			—		—
RSU's granted		151,665			25.60		—
Outstanding at December 31, 2012		151,665		$	25.60	$	—
RSU's granted		156,415			23.72		—
RSU's vested		(55,832	)		27.06		—
RSU's cancelled		(3,333	)		24.75		—
Outstanding at December 31, 2013		248,915		$	24.10	$	—

Intrinsic value is calculated as the difference between, the per share market price of our common stock on the last trading day of 2013, which was $19.41, and the exercise price of the options.  For options exercised, the intrinsic value is the difference between market price and the exercise price on the date of exercise. We received cash proceeds of $170, $1,691 and $1,068 from stock options exercised in 2013, 2012 and 2011 respectively. The total intrinsic value of options exercised was $676, $11,509 and $8,050 during the years ended December 31, 2013, 2012 and 2011, respectively.  The aggregate intrinsic value of options exercisable at December 31, 2013 was $63,490. For RSU’s vested, the intrinsic value is the difference between market price and the vested price on the date of vest. The total intrinsic value of the RSU’s vested was zero during the year ended December 31, 2013.

Stock-based compensation expense is included in general and administrative expense for each period as follows:

Stock-Based Compensation by Type of Award	Year Ended December 31, 2013		Year Ended December 31, 2012		Year Ended December 31, 2011
Employee stock options	$	6,488	$	5,171	$	4,367
RSU’s		1,075		991		—
Total stock-based compensation expense	$	7,563	$	6,162	$	4,367

As of December 31, 2013, there was $11,752 of unrecognized stock-based compensation expense expected to be recognized related to unvested employee stock options and 4,773 of unrecognized stock-based compensation expense to be recognized related to unvested RSU’s. These costs are expected to be recognized over a weighted-average period of 2.39 and 2.70 years, respectively.

The fair value of each option grant was estimated on the date of grant using the Black-Scholes option pricing model using the following weighted average assumptions:

	Year Ended December 31, 2013			Year Ended December 31, 2012			Year Ended December 31, 2011
Expected stock price volatility		93	%		111	%		123	%
Risk-free interest rate		2.04	%		1.90	%		3.05	%
Expected life term (in years)	6.10 years			6.8 years			6.6 years
Expected dividends		0	%		0	%		0	%

Based on the Black-Scholes option pricing model, the weighted average estimated fair value of employee stock options granted was $19.24, $23.17 and $21.43 per share during the years ended December 31, 2013, 2012 and 2011, respectively.

The expected life was determined using the simplified method outlined in ASC 718, taking the average of the vesting term and the contractual term of the option.  Expected volatility of the stock options was based upon historical data and other relevant factors, such as the volatility of comparable publicly-traded companies at a similar stage of life cycle.  We have not provided an estimate for forfeitures because we have had nominal forfeited options and believe that all outstanding options at December 31, 2013, will vest.  In the future, we may change this estimate based on actual and expected future forfeiture rates.