Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2012

Stock-Based Compensation

Schedule of stock-based compensation expense included in the entity's consolidated statements of operations

	Year Ended December 31,
	2012			2011			2010
Employee stock purchase plan(1)	$	(112	)	$	54		$	14
Employee stock options		1,980			1,438			1,197
Restricted stock unit awards		4,896			4,320			2,812
Modifications to stock option agreements		93			364			840
Share-based compensation expense before tax		6,857			6,176			4,863
Income tax benefit (at 35% statutory rate)		(2,400	)		(2,162	)		(1,702	)
Net stock-based compensation expense	$	4,457		$	4,014		$	3,161

⁽¹⁾

The income during December 31, 2012 is a result of ESPP disqualifications in excess of ESPP expense.

Schedule of additional information regarding stock options

 The following table provides additional information regarding our stock options for the year ended December 31, 2012 as follows (in thousands, except per share data):

	Shares			Weighted- Average Exercise Price Per Share
Outstanding at the beginning of the year		4,363		$	2.79
Granted during the year		963			6.12
Exercised or converted during the year		(284	)		2.48
Forfeited during the year		(112	)		4.38
Expired during the year		(36	)		4.02
Outstanding at the end of the year		4,894			3.42
Exercisable or convertible at the end of the year		3,116			2.47

Schedule of assumptions used to estimate the fair value of each stock option grant or modification on the date of grant

	Year Ended December 31,
	2012	2011	2010
Expected term(1)	5 to 6 years	5 to 6 years	5 to 6 years
Expected volatility(2)	98% to 99%	97% to 99%	95% to 96%
Expected dividends	$0.00	$0.00	$0.00
Risk-free rate(3)	0.6% to 1.1%	0.9% to 2.6%	1.9% to 2.7%

⁽¹⁾

The expected term was estimated using our historical experience.

⁽²⁾

Expected volatility is based on historical trends for our class A common stock over the expected term, and prior to 2010, we used the historical trends of our class A common stock over the expected term, as well as a comparison to peer companies.

⁽³⁾

The risk-free interest rate for each grant is equal to the U.S. Treasury yield curve in effect at the time of grant for instruments with a similar expected life.

Schedule of additional information regarding the restricted stock unit awards

  The following table provides additional information regarding the restricted stock unit awards for the year ended December 31, 2012 (in thousands, except per share data):

	Shares			Weighted- Average Price Per Share
Unvested at the beginning of the year		2,579		$	5.75
Granted during the year		675			6.61
Vested during the year		(851	)		5.85
Forfeited during the year		(109	)		5.34
Unvested at the end of the year		2,294			5.98

Schedule of information for restricted stock unit and stock option awards

	Year Ended December 31,
	2012		2011		2010
Total fair value of awards granted	$	10,347	$	4,983	$	16,057
Total intrinsic value of awards exercised		865		225		796
Total fair value of awards vested		7,718		7,522		6,786