Stock-based Compensation (Tables)

6 Months Ended

Jun. 30, 2016

Stock-based Compensation Expense

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

	Three Months Ended June 30,				Six Months Ended June 30,
	2016		2015		2016		2015
Cost of net revenues	$	932	$	967	$	1,893	$	1,945
Selling, general and administrative	10,843		9,771		20,677		18,542
Research and development	1,924		2,088		3,653		3,987
Total stock-based compensation	$	13,699	$	12,826	$	26,223	$	24,474

Stock Option Activity

Activity for the six months ended June 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	(130	)	15.17
Cancelled or expired	—		—
Outstanding as of June 30, 2016	366		$	15.13	1.26	$	23,942
Vested and expected to vest at June 30, 2016	366		$	15.13	1.26	$	23,942
Exercisable at June 30, 2016	366		$	15.13	1.26	$	23,942

^[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:

	Six Months Ended June 30,
	2016			2015
Expected term (in years)	1.3			1.2
Expected volatility	33.7		%	31.9		%
Risk-free interest rate	0.77		%	0.26		%
Expected dividends	—			—
Weighted average fair value at grant date	$	19.96		$	15.98

Restricted Stock Units (RSUs)

Summary Of Nonvested Shares

A summary of the RSU activity for the six months ended June 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	650		65.58
Vested and released	(715	)	45.02
Forfeited	(96	)	52.12
Nonvested as of June 30, 2016	1,918		$	56.44	1.50	$	154,520

Market Performance Based Restricted Stock Units

Summary Of Nonvested Shares

The following table summarizes the MSU activity for the six months ended June 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	218		55.77
Vested and released	(252	)	35.49
Forfeited	(39	)	56.41
Nonvested as of June 30, 2016	538		$	60.28	1.60	$	43,356

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