Stockholders' Equity (Tables)

9 Months Ended

Sep. 30, 2013

Stockholders' Equity [Abstract]

Summary of stock option activity

Stock Options

The following table represents the stock option activity for the nine months ended September 30, 2013:

	Number of Shares			Weighted Average Exercise Price per Share		Weighted Average Remaining Contractual Term		Aggregate Intrinsic Value (in thousands)
Outstanding options at December 31, 2012		9,529,597		$	3.05		3.63	$	12,595
Granted		256,550		$	4.37
Exercised		(3,771,188	)	$	2.53
Forfeited		(216,049	)	$	4.33
Outstanding options at September 30, 2013		5,798,910		$	3.40		3.51	$	12,436
Options vested and expected to vest		5,742,681		$	3.40		3.48	$	12,347
Exercisable at September 30, 2013		4,541,237		$	3.23		2.95	$	10,420

Summary of restricted stock units activity

The following table represents RSU activity for the nine months ended September 30, 2013:

	Number of Shares			Weighted Average Grant Date Fair Value
Outstanding RSUs at December 31, 2012		98,363		$	2.82
Granted		1,443,112		$	5.05
Vested		(108,363	)	$	2.98
Forfeited		(16,300	)	$	5.89
Outstanding RSUs at September 30, 2013		1,416,812		$	5.04