Stock-based Compensation (Tables)

9 Months Ended

Sep. 30, 2016

Stock-based Compensation Expense

The stock-based compensation related to all of our stock-based awards and employee stock purchases for the three and nine months ended September 30, 2016 and 2015 is as follows (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2016		2015		2016		2015
Cost of net revenues	$	995	$	984	$	2,888	$	2,929
Selling, general and administrative	10,797		11,564		31,474		30,106
Research and development	1,919		2,113		5,572		6,100
Total stock-based compensation	$	13,711	$	14,661	$	39,934	$	39,135

Stock Option Activity

Activity for the nine months ended September 30, 2016 under the stock option plans is set forth below (in thousands, except years and per share amounts):

	Stock Options Number of Shares Underlying Stock Options		Weighted Average Exercise Price per Share		Weighted  Average Remaining Contractual  Term (In Years)	Aggregate Intrinsic Value
Outstanding as of December 31, 2015	496		$	15.14
Granted	—		—
Exercised	(224	)	14.69
Cancelled or expired	—		—
Outstanding as of September 30, 2016	272		$	15.52	1.25	$	21,248
Vested and expected to vest at September 30, 2016	272		$	15.52	1.25	$	21,248
Exercisable at September 30, 2016	272		$	15.52	1.25	$	21,248

^[1]

Schedule of Share-based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions

The fair value of the option component of the 2010 Purchase Plan shares was estimated at the grant date using the Black-Scholes option pricing model with the following weighted average assumptions:

	Three Months Ended September 30,						Nine Months Ended September 30,
	2016			2015			2016			2015
Expected term (in years)	1.2			1.2			1.2			1.2
Expected volatility	27.4		%	27.9		%	30.5		%	31.1		%
Risk-free interest rate	0.53		%	0.41		%	0.65		%	0.29		%
Expected dividends	—			—			—			—
Weighted average fair value at grant date	$	24.44		$	17.10		$	22.23		$	16.19

Restricted Stock Units (RSUs)

Summary Of Nonvested Shares

A summary of the RSU activity for the nine months ended September 30, 2016 is as follows (in thousands, except years):

	Number of Shares Underlying RSU		Weighted Average Grant Date Fair Value		Weighted  Remaining Contractual  Period	Aggregate Intrinsic  Value
					(in years)
Nonvested as of December 31, 2015	2,079		$	49.45
Granted	683		66.64
Vested and released	(774	)	44.89
Forfeited	(120	)	52.86
Nonvested as of September 30, 2016	1,868		$	57.42	1.29	$	175,091

Market Performance Based Restricted Stock Units

Summary Of Nonvested Shares

The following table summarizes the MSU activity for the nine months ended September 30, 2016 (in thousands, except years):

	Number of Shares Underlying MSU		Weighted Average Grant Date Fair Value		Weighted Average Remaining Contractual Period	Aggregate Intrinsic  Value
					(in years )
Nonvested as of December 31, 2015	611		$	51.41
Granted	219		55.77
Vested and released	(271	)	36.73
Forfeited	(39	)	56.41
Nonvested as of September 30, 2016	520		$	60.49	1.35	$	48,783

[1] There were no stock options granted during the nine months ended September 30, 2016 and 2015. All compensation costs relating to stock options have been recognized as of September 30, 2016.