Common Stock, Preferred Stock and Equity Plans (Tables)

12 Months Ended

Dec. 31, 2017

Equity [Abstract]

Schedule of stock and stock equity plans

The following table contains information about the Company’s equity plans:

			As of December 31, 2017
Title of Plan	Group Eligible	Type of Award Granted	Awards Outstanding	Additional Awards Authorized for Grant
2013 Stock and Option Plan	Employees, Non-employee Directors and Consultants	NSO, RS, RSU and PSU	10,388,723	11,427,114
2006 Stock and Option Plan	Employees, Non-employee Directors and Consultants	NSO, RS and RSU	3,102,768	—
		Total	13,491,491	11,427,114

Outstanding and vested options

The following table summarizes information related to the outstanding and exercisable options during the year ended December 31, 2017:

	Stock Options		Weighted-average Exercise Price		Weighted-average Remaining Contractual Life	Aggregate Intrinsic Value
	(in thousands)		(per share)		(in years)	(in thousands)
Outstanding at December 31, 2016	12,642		$	81.41
Granted	2,359		$	108.43
Exercised	(4,561	)	$	70.90
Forfeited	(611	)	$	99.53
Expired	(62	)	$	105.24
Outstanding at December 31, 2017	9,767		$	91.57	6.95	$	585,293
Exercisable at December 31, 2017	5,313		$	80.14	5.75	$	375,472

Stock options outstanding and exercisable

The following table summarizes information about stock options outstanding and exercisable at December 31, 2017:

	Options Outstanding				Options Exercisable
Range of Exercise Prices	Number Outstanding	Weighted-average Remaining Contractual Life	Weighted-average Exercise Price		Number Exercisable	Weighted-average Exercise Price
	(in thousands)	(in years)	(per share)		(in thousands)	(per share)
$18.93–$20.00	128	0.10	$	18.93	128	$	18.93
$20.01–$40.00	810	1.88	$	34.43	810	$	34.43
$40.01–$60.00	798	4.49	$	49.15	798	$	49.15
$60.01–$80.00	746	6.19	$	75.49	653	$	75.40
$80.01–$100.00	4,350	8.07	$	89.31	1,514	$	89.51
$100.01–$120.00	1,087	7.11	$	109.34	633	$	109.24
$120.01–$140.00	1,223	7.63	$	130.20	734	$	129.89
$140.01–$160.00	—	—	$	—	—	$	—
$160.01–$163.74	625	9.54	$	162.94	43	$	162.94
Total	9,767	6.95	$	91.57	5,313	$	80.14

Restricted stock and restricted stock units activity

The following table summarizes the restricted stock and restricted stock unit activity of the Company during the year ended December 31, 2017:

	Restricted Stock				Restricted Stock Units (excluding PSUs)
	Number of Units		Weighted-average Grant-date Fair Value		Number of Shares		Weighted-average Grant-date Fair Value
	(in thousands)		(per share)		(in thousands)		(per share)
Unvested at December 31, 2016	2,613		$	102.54	798		$	92.62
Granted	—		$	—	1,719		$	113.13
Vested	(1,206	)	$	102.99	(278	)	$	94.72
Cancelled	(178	)	$	102.45	(228	)	$	97.86
Unvested at December 31, 2017	1,229		$	102.12	2,011		$	109.27

PSU activity

The following table summarizes the PSU activity of the Company during the year ended December 31, 2017:

	Performance-Based RSU
	Number of Units		Weighted-average Grant-date Fair Value
	(in thousands)		(per share)
Unvested at December 31, 2016 (1)	135		$	91.05
Granted (2)	392		$	86.71
Vested	(15	)	$	91.05
Cancelled	(28	)	$	86.52
Unvested at December 31, 2017	484		$	87.59
(1) Represents the Company’s 2016 PSUs based on the target number of shares issuable at the end of each of the financial and non-financial performance periods.
(2) Represents (i) the target number of shares issuable for the Company’s 2017 PSUs at the end of each of the financial and non-financial performance periods and (ii) a decrease in shares issuable under 2016 PSUs based on 2016 financial performance.

Shares issued under Employee Stock Purchase Plan

In 2017, the following shares were issued to employees under the ESPP:

	Year Ended December 31, 2017
	(in thousands, except per share amount)
Number of shares	275
Average price paid per share	$	80.71