Employee Benefits and Share-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2018

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

Share-Based Compensation Expense Recognized in Consolidated Statements of Income

The following table sets forth the total share-based compensation expense recognized in the Company’s Consolidated Statements of Operations:

	Year Ended December 31,
	2018		2017		2016
	(In thousands)
Cost of product and service revenues	$	4,634	$	3,478	$	2,596
Research and development	5,746		3,590		3,128
Selling, general, and administrative	18,505		14,789		13,776
Total share-based compensation expense	$	28,885	$	21,857	$	19,500

Estimate of Fair Value of Share-Based Awards, Stock Options

The following assumptions were used to value stock options and ESPP shares granted pursuant to the Company’s equity incentive plans for the years ended December 31, 2018, December 31, 2017, and December 31, 2016:

	Year Ended December 31,
	2018		2017		2016
Stock options
Expected life, years	4.8		4.7		4.9
Expected volatility, %	31.1	%	29.6	%	30.6	%
Risk-free interest rate, %	2.8	%	1.9	%	1.5	%
Estimated forfeiture rate, %	6.9	%	7.7	%	8.6	%
Dividend yield, %	—	%	—	%	—	%

Estimate of Fair Value of Share-Based Awards, Employee Stock Purchase Plan

	Year Ended December 31,
	2018		2017		2016
Employee stock purchase plan shares
Expected life, years	0.5 - 2.0		0.5 - 2.0		0.5 - 2.0
Expected volatility, %	28.1% - 33.8%		25.8% - 32.8%		25.8% - 34.8%
Risk-free interest rate, %	0.8% - 2.7%		0.5% - 1.4%		0.3% - 0.8%
Dividend yield, %	—	%	—	%	—	%

Stock Option Activity under the 2009 Plan

The following table summarizes the share option activity under the Company’s 2009 Plan during the year ended December 31, 2018:

	Number of Shares		Weighted-Average Exercise Price		Weighted-Average Remaining Years	Aggregate Intrinsic Value
	(In thousands, except per share data)
Outstanding at December 31, 2017	3,323		$	32.72	7.6	$	53,953
Granted	1,359		54.00
Exercised	(672	)	25.68
Expired	(16	)	26.54
Forfeited	(246	)	39.60
Outstanding at December 31, 2018	3,748		$	41.27	7.6	$	78,365
Exercisable at December 31, 2018	1,397		29.69		5.7	44,084
Vested and expected to vest at December 31, 2018 and thereafter	3,532		$	40.64	7.6	$	75,823

Restricted Stock Units Activity under the 2009 Plan

Summaries of the restricted stock activity under the 2009 Plan are presented below for the year ended December 31, 2018:

	Number of Shares		Weighted-Average Grant Date Fair Value		Weighted-Average Remaining Years	Aggregate Intrinsic Value
	(In thousands, except per share data)
Restricted stock units
Outstanding at December 31, 2017	501		$	38.90	1.5	$	24,293
Granted (Awarded)	312		59.52
Vested (Released)	(213	)	37.14
Forfeited	(62	)	39.00
Outstanding and unvested at December 31, 2018	538		$	51.52	1.6	$	32,935

Restricted Stock Awards under the 2009 Plan

	Number of Shares		Weighted-Average Grant Date Fair Value
	(In thousands, except per share data)
Restricted stock awards
Outstanding at December 31, 2017	23		$	41.07
Granted (Awarded)	21		46.60
Vested (Released)	(23	)	41.07
Outstanding and unvested at December 31, 2018	21		$	46.60

Restricted Stock Activity (Performance based) under the 2009 Plan

A summary of the performance-based restricted stock activity under the 2009 Plan is presented below for the year ended December 31, 2018:

	Number of Shares		Weighted-Average Grant Date Fair Value Per Unit
	(In thousands, except per share data)
Outstanding at December 31, 2017	225		$	31.18
Granted	110		38.03
Vested	(106	)	30.54
Forfeited	(32	)	34.47
Outstanding and unvested at December 31, 2018	197		$	34.83

Schedule of Share-based Compensation, Future Issuance of Shares

The Company had the following ordinary shares reserved for future issuance under its equity incentive plans as of December 31, 2018:

	Number of Shares
	(In thousands)
Share options outstanding	3,748
Non-vested restricted stock awards	755
Shares authorized for future issuance	2,431
ESPP shares available for future issuance	1,913
Total shares reserved for future issuance	8,847