Employee Benefit Plans (Tables)

3 Months Ended

Apr. 01, 2018

Employee Benefits and Share-based Compensation, Noncash [Abstract]

Schedule of Stock Option Activity

Stock option activity during the three months ended April 1, 2018 was as follows:

	Number of shares		Weighted Average Exercise Price Per Share
	(In thousands)		(In dollars)
Outstanding as of December 31, 2017	1,879		$	34.08
Granted	348		70.15
Exercised	(73	)	25.56
Cancelled	—		—
Expired	(5	)	20.07
Outstanding as of April 1, 2018	2,149		$	40.25

Schedule of RSU Activity

RSU activity during the three months ended April 1, 2018 was as follows:

	Number of shares		Weighted Average Grant Date Fair Value Per Share
	(In thousands)		(In dollars)
Outstanding as of December 31, 2017	1,130		$	43.22
Granted	608		70.15
Vested	(109	)	41.09
Cancelled	(12	)	49.67
Outstanding as of April 1, 2018	1,617		$	53.44

Schedule of Weighted Average Assumptions

The table below sets forth the weighted average assumptions used to estimate the fair value of option grants and purchase rights granted under the ESPP during the three months ended April 1, 2018 and April 2, 2017.

	Three Months Ended
	Stock Options			ESPP
	April 1, 2018		April 2, 2017	April 1, 2018		April 2, 2017
Expected life (in years)	4.4		NA	0.5		0.5
Risk-free interest rate	2.32	%	NA	1.81	%	0.66	%
Expected volatility	30.9	%	NA	37.1	%	27.6	%
Dividend yield	—		NA	—		—

Schedule of Total Stock-Based Compensation Expense Resulting from Stock Options, Restricted Stock Awards, and the Employee Stock Purchase Plan

The following table sets forth the stock-based compensation expense resulting from stock options, RSUs and the ESPP included in the Company’s unaudited condensed consolidated statements of operations:

	Three Months Ended
	April 1, 2018		April 2, 2017
	(In thousands)
Cost of revenue	$	852	$	436
Research and development	1,575		1,319
Sales and marketing	2,531		1,247
General and administrative	3,192		2,126
Total stock-based compensation	$	8,150	$	5,128