Equity Incentive Plans and Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2014

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Shares available for grant under stock-based incentive plans

A summary of shares available for grant under the Company’s plans is as follows:



	Shares Available for Grant
Shares available as of December 31, 2013	2,527,428
Increase in shares approved for issuance	10,000,000
Stock options granted	(2,168,309	)
Stock options forfeited	994,532
Stock options expired under former plans	(157,000	)
Nonvested equity stock and stock units granted (1)	(421,908	)
Nonvested equity stock and stock units forfeited (1)	64,680
Total available for grant as of September 30, 2014	10,839,423

_________________________________________


(1)	For purposes of determining the number of shares available for grant under the 2006 Plan against the maximum number of shares authorized, each share of restricted stock granted reduces the number of shares available for grant by 1.5 shares and each share of restricted stock forfeited increases shares available for grant by 1.5 shares.

Schedule of stock option activity

The following table summarizes stock option activity under the 1997 Plan and 2006 Plan for the nine months ended September 30, 2014 and information regarding stock options outstanding, exercisable, and vested and expected to vest as of September 30, 2014.



	Options Outstanding
	Number of Shares		Weighted Average Exercise Price Per Share		Weighted Average Remaining Contractual Term (years)	Aggregate Intrinsic Value
	(In thousands, except per share amounts)
Outstanding as of December 31, 2013	11,377,146		$	11.32
Options granted	2,168,309		$	9.43
Options exercised	(808,643	)	$	7.02
Options forfeited	(994,532	)	$	15.92
Outstanding as of September 30, 2014	11,742,280		$	10.88	6.09	$	47,629
Vested or expected to vest at September 30, 2014	11,076,127		$	11.06	5.94	$	44,436
Options exercisable at September 30, 2014	6,135,339		$	14.14	4.17	$	17,678

Weighted-average assumptions for Stock Option Plans

The following table presents the weighted-average assumptions used to estimate the fair value of stock options granted that contain only service conditions in the periods presented.



	Stock Option Plans
	Three Months Ended						Nine Months Ended
	September 30,						September 30,
	2014			2013			2014		2013
Stock Option Plans
Expected stock price volatility	44		%	45		%	40-44%		45-47%
Risk free interest rate	2.1		%	1.5		%	2.1-2.2%		0.8-1.5%
Expected term (in years)	6.0			5.5			6.0-6.1		5.4-5.5
Weighted-average fair value of stock options granted to employees	$	5.81		$	4.00		$	4.20	$	2.48

Weighted- average assumptions for Employee Stock Purchase Plan



	Employee Stock Purchase Plan
	Nine Months Ended
	September 30,
	2014		2013
Employee Stock Purchase Plan
Expected stock price volatility	39-44%		48		%
Risk free interest rate	0.0-0.1%		0.1		%
Expected term (in years)	0.02-0.5		0.5
Weighted-average fair value of purchase rights granted under the purchase plan	$	3.91	$	1.94

Schedule of nonvested equity stock and stock units activity

The following table reflects the activity related to nonvested equity stock and stock units for the nine months ended September 30, 2014:



Nonvested Equity Stock and Stock Units	Shares		Weighted- Average Grant-Date Fair Value
Nonvested at December 31, 2013	629,649		$	8.56
Granted	281,272		$	9.83
Vested	(168,915	)	$	10.01
Forfeited	(43,113	)	$	7.37
Nonvested at September 30, 2014	698,893		$	8.79