Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2015

Summary of option activity

				Weighted-Average
	Outstanding Options			Remaining	Aggregate
	Number of	Weighted-Average		Contractual	Intrinsic
	Shares	Exercise Price		Life	Value
	(In thousands)	(In years)			(In thousands)
Balance at December 31, 2014	3,777	$	22.10
Options granted	450	$	30.38
Options exercised	(489)	$	15.34
Options forfeited	(47)	$	29.96
Options expired	(61)	$	29.73
Balance at December 31, 2015	3,630	$	23.80	5.1	$	41,402
Exercisable at December 31, 2015	2,872	$	22.06	4.1	$	37,776
Vested and expected to vest at December 31, 2015	3,572	$	23.69	5.0	$	41,144

Summary of RSU activity

		Weighted-Average
	Number of	Grant Date Fair
	Shares	Value
	(In thousands)
Balance at December 31, 2014	630	$	29.65
RSUs granted	443	$	30.65
RSUs vested	(308)	$	29.78
RSUs cancelled	(83)	$	30.17
Balance at December 31, 2015	682	$	30.18

Schedule of the impact of employee stock-based compensation expense on selected statement of operations line items

	Year Ended December 31,
	2015		2014		2013
	(In thousands)
Cost of product revenues	$	525	$	497	$	483
Research and development		4,228		4,143		4,486
Selling and marketing		4,526		4,822		4,756
General and administrative		6,726		7,076		7,732
Total	$	16,005	$	16,538	$	17,457

Schedule of weighted-average fair values and assumptions used in calculation of fair value of stock options and employee stock purchase plan

	Year Ended December 31,
	2015			2014			2013
Expected volatility:
Stock options		44	%		44	%		46	%
ESPP		35	%		37	%		39	%
Risk-free interest rate:
Stock options		1.66	%		1.97	%		1.40	%
ESPP		0.10	%		0.08	%		0.11	%
Expected life in years:
Stock options		5.94			6.61			6.64
ESPP		0.50			0.50			0.50
Weighted-average fair value:
Stock options	$	13.37		$	14.13		$	14.11
ESPP	$	6.99		$	7.24		$	7.82

Performance-Based Vesting

Summary of RSU activity

		Weighted-Average
	Number of	Grant Date Fair
	Shares	Value
	(In thousands)
Balance at December 31, 2014	14	$	27.21
PVRSUs granted	23	$	31.12
PVRSUs vested	(7)	$	27.21
PVRSUs cancelled	(24)	$	31.02
Balance at December 31, 2015	6	$	27.21