Employee Benefits and Share-Based Compensation - (Tables)

9 Months Ended

Sep. 30, 2019

Share-based Payment Arrangement [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 Condensed Consolidated Statements of Operations for the three and nine months ended September 30, 2019 and 2018:

	Three months ended September 30,				Nine months ended September 30,
	2019		2018		2019		2018
	(In thousands)
Cost of product and service revenues	$	1,316	$	1,150	$	4,194	$	3,346
Research and development	1,652		1,397		4,938		4,068
Selling, general, and administrative	5,537		4,538		16,043		13,437
Total share-based compensation expense	$	8,505	$	7,085	$	25,175	$	20,851

Stock Option Plans, Valuation Assumptions

The following assumptions were used to value stock options and Employee Stock Purchase Plan (“ESPP”) shares granted pursuant to the Company’s equity incentive plans for the three and nine months ended September 30, 2019 and 2018:

	Three months ended September 30,				Nine months ended September 30,
	2019		2018		2019		2018
Stock options
Expected life, years	4.3		4.8		4.4		4.8
Expected volatility, %	34.7	%	30.4	%	33.7	%	31.1	%
Risk-free interest rate, %	1.6	%	2.8	%	2.1	%	2.7	%
Estimated forfeiture rate, %	7.2	%	6.9	%	7.2	%	6.9	%
Dividend yield, %	—	%	—	%	—	%	—	%

Employee Stock Purchase Plan, Valuation Assumptions

	Three months ended September 30,				Nine months ended September 30,
	2019		2018		2019		2018
Employee stock purchase plan shares
Expected life, years	0.5 - 2.0		0.5 - 2.0		0.5 - 2.0		0.5 - 2.0
Expected volatility, %	28.9% - 39.9%		28.1% - 33.8%		28.2% - 39.9%		27.7% - 33.8%
Risk-free interest rate, %	1.4% - 2.7%		0.8% - 2.7%		1.3% - 2.7%		0.7% - 2.7%
Dividend yield, %	—	%	—	%	—	%	—	%

Stock Option Activity under the Equity Incentive Plans

The following table summarizes the share option activity under the Company’s equity incentive plans during the nine months ended September 30, 2019:

	Number of Shares		Weighted-Average Exercise Price		Weighted-Average Remaining Years	Aggregate Intrinsic Value
	(In thousands, except per share data)
Outstanding at December 31, 2018	3,748		$	41.27	7.6	$	78,365
Granted	687		75.49
Exercised	(597	)	32.66
Expired	(9	)	37.08
Forfeited	(234	)	47.23
Outstanding at September 30, 2019	3,595		$	48.86	7.7	$	87,453
Exercisable at September 30, 2019	1,470		$	33.91	6.3	$	56,377
Vested and expected to vest at September 30, 2019 and thereafter	3,401		$	48.07	7.7	$	85,235

Restricted Stock Units Activity under the Equity Incentive Plans

Summaries of the restricted stock activity under the Company’s 2009 Equity Incentive Plan, as amended (the “2009 Plan”) are presented below for the nine months ended September 30, 2019:

	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, 2018	538		$	51.52	1.6	$	32,935
Granted (Awarded)	77		77.48
Vested (Released)	(120	)	40.87
Forfeited	(49	)	47.21
Outstanding and unvested at September 30, 2019	446		$	59.39	1.3	$	32,199

Restricted Stock Awards Activity under the Equity Incentive Plans

	Number of Shares		Weighted-Average Grant Date Fair Value
	(In thousands, except per share data)
Restricted stock awards
Outstanding at December 31, 2018	21		$	46.60
Granted (Awarded)	17		81.86
Vested (Released)	(21	)	46.96
Forfeited	—		—
Outstanding and unvested at September 30, 2019	17		$	81.92

Performance-Based Restricted Stock under the Equity Incentive Plans

A summary of the performance-based restricted stock activity under the 2009 Plan is presented below for the nine months ended September 30, 2019:

	Number of Shares		Weighted-Average Grant Date Fair Value Per Unit
	(In thousands, except per share data)
Outstanding at December 31, 2018	197		$	34.83
Granted	71		73.38
Vested	(68	)	35.74
Forfeited	(33	)	33.84
Outstanding and unvested at September 30, 2019	167		$	51.07

Shares Reserved for Future Issuance under the Equity Incentive Plans

The Company had the following ordinary shares reserved for future issuance under its equity incentive plans as of September 30, 2019:

	Number of Shares
	(In thousands)
Share options outstanding	3,595
Non-vested restricted share awards	630
Shares authorized for future issuance	3,672
ESPP shares available for future issuance	1,539
Total shares reserved for future issuance	9,436