Equity Awards (Tables)

12 Months Ended

Dec. 31, 2018

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

Information About Outstanding And Vested Stock Options

A summary of stock option activity was as follows:

	Number of Shares		Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2016	5,818,435		$	20.57
Granted	616,720		86.33
Exercised	(2,970,914	)	12.44			$	277,670
Canceled	(94,509	)	68.88
Outstanding at December 31, 2017	3,369,732		38.43
Exercised	(1,461,712	)	26.23			$	204,337
Canceled	(97,440	)	70.52
Outstanding at December 31, 2018	1,810,580		$	46.55	5.30	$	238,092
Vested and expected to vest as of December 31, 2018	1,804,158		$	46.45	5.29	$	237,425
Vested and exercisable as of December 31, 2018	1,319,851		$	32.90	4.30	$	191,580

Restricted Stock Unit Table

A summary of RSU activity was as follows:

	Number of Shares		Weighted Average Grant Date Fair Value (Per Share)		Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2016	12,222,282		$	63.66
Granted	6,320,457		95.70
Vested	(5,502,004	)	60.79		$	573,861
Forfeited	(1,637,394	)	72.69
Outstanding at December 31, 2017	11,403,341		81.50
Granted	5,302,586		160.08
Vested	(5,485,868	)	77.38		$	931,848
Forfeited	(1,018,399	)	100.55
Outstanding at December 31, 2018	10,201,660		$	121.84	$	1,816,406
Expected to vest as of December 31, 2018	9,236,535				$	1,644,565