Employee Equity Incentive Plans and Stock-Based Compensation Expense (Tables)

3 Months Ended

Mar. 31, 2016

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

Summary of stock-based compensation expense

The following table is a summary of the major categories of stock-based compensation expense recognized in accordance with ASC 718, “Compensation—Stock Compensation” (“ASC 718”) for the three months ended March 31, 2016 and 2015 (in thousands):

	Three Months Ended   March 31,
	2016		2015
Cost of sales	$	1,515	$	1,040
Research and development	2,278		2,198
Sales and marketing	1,929		1,450
General and administrative	3,316		2,869
Total stock-based compensation expense	$	9,038	$	7,557

Summary of option activity

The following table summarizes option activity under all plans (in thousands, except weighted average exercise price and weighted average remaining contractual term):

	Shares		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (in years)	Intrinsic Value
Outstanding, December 31, 2015	5,442		$	39.46
Granted	308		$	32.27
Exercised	(76	)	$	9.33
Forfeited	(54	)	$	42.41
Outstanding, March 31, 2016	5,620		$	39.45	4.05	$	13,888
Exercisable, March 31, 2016	3,249		$	33.40	2.86	$	13,223
Vested and expected to vest, March 31, 2016	5,452		$	39.22	3.99	$	13,810

Summary of restricted stock plan activity

The following table summarizes all award activity, which consists of restricted stock awards and restricted stock units (in thousands, except weighted average grant date fair value):

	Shares		Weighted Average Grant Date Fair Value
Outstanding, December 31, 2015	1,000		$	48.44
Granted	101		32.89
Vested	(55	)	43.46
Cancelled	(24	)	46.72
Outstanding, March 31, 2016	1,022		$	47.21

Summary of assumptions to estimate fair value

The following table summarizes the assumptions used in determining the fair value of the Company’s stock options granted to employees and directors and shares purchased by employees under the Company’s 2012 Employee Stock Purchase Plan (“ESPP”):

	Three Months Ended   March 31,
	2016			2015
OPTION SHARES:
Expected Term (in years)	4.33			4.40
Volatility	.36			.38
Expected Dividends	—			—
Risk Free Interest Rates	1.39		%	1.39		%
Estimated Forfeitures	6.14		%	6.75		%
Weighted Average Fair Value Per Share	$	10.13		$	18.55
ESPP SHARES:
Expected Term (in years)	1.23			1.22
Volatility	.49			.32
Expected Dividends	—			—
Risk Free Interest Rates	0.59		%	0.26		%
Weighted Average Fair Value Per Share	$	9.87		$	16.43