Common Stock and Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2018

Summary of Stock Options under Employee Equity Incentive Plan and Stock Option Plan for Non-Employee Directors

Information related to stock options under the Employee Equity Incentive Plan and the Stock Option Plan for Non-Employee Directors is summarized as follows:

	Shares			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term in Years		Aggregate Intrinsic Value (in thousands)
Outstanding at December 30, 2017		1,156,997		$	158.53
Granted		17,531			191.10
Forfeited		—			—
Expired		—			—
Exercised		(168,773	)		113.82
Outstanding at March 31, 2018		1,005,755		$	178.90		6.97	$	19,949
Exercisable at March 31, 2018		178,692		$	104.02		3.54	$	16,108
Vested and expected to vest at March 31, 2018		374,181		$	143.93		5.58	$	19,015

Summary of Vesting Activities of Shares Issued Under Investment Share Program and Restricted Stock Awards

The following table summarizes vesting activities of shares issued under the investment share program and restricted stock awards:

	Number of Shares			Weighted Average Fair Value
Non-vested at December 30, 2017		62,405		$	155.21
Granted		28,087			156.90
Vested		(18,918	)		152.19
Forfeited		(1,012	)		108.71
Non-vested at March 31, 2018		70,562		$	157.36