Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2013

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Fair Values of Options Granted Estimated Using Weighted-Average Assumptions

The Company uses the Black-Scholes option pricing model to calculate the grant-date fair value of an award. The Company calculated the fair values of the options granted using the following estimated weighted-average assumptions:

	Years Ended December 31,
	2013	2012	2011
Expected volatility	67%	88%	79%-81.4%
Expected term	5 years	5 years	6.25 years
Risk-free interest rate	0.58%	0.36%	0.9%-2.3%
Expected dividend yield	—%	—%	—%
Weighted-average grant date fair value per share	$3.89	$3.63	$4.72

Summary of Stock Option Activity under Company's Stock Option Plan

A summary of the stock option activity under the Company’s stock option plan for the year ended December 31, 2013 is presented below:

	Options Outstanding			Weighted-Average Exercise Price Per Share		Weighted-Average Remaining Contractual Term in Years		Aggregate Intrinsic Value
Options outstanding at December 31, 2012		5,486,687		$	6.88
Granted		10,000			7.03
Exercised		(566,838	)		2.75
Forfeited		(33,125	)		6.44
Canceled		(429,476	)		7.98
Options outstanding at December 31, 2013		4,467,248		$	7.30		3.4	$	2,416
Options exercisable at December 31, 2013		4,427,873		$	7.30		3.3	$	2,411
Options vested or expected to vest at December 31, 2013(1)		4,462,875		$	7.30		3.4	$	2,415

(1) In addition to the vested options, the Company expects a portion of the unvested options to vest at some point in the future. Options expected to vest is calculated by applying an estimated forfeiture rate to the unvested options.

Summary of Restricted Stock Award Activity under 2007 Stock Plan

A summary of the restricted stock award activity under the 2007 Plan for the year ended December 31, 2013 is presented below:

	Shares			Weighted-Average Grant Date Fair Value Per Share		Aggregate Intrinsic Value
Nonvested outstanding at December 31, 2012		2,992,187		$	5.16
Granted		864,695			5.63
Vested		(949,382	)		5.28
Forfeited		(130,000	)		5.30
Nonvested outstanding at December 31, 2013		2,777,500		$	5.26	$	19,054