Equity Award Plan Activities (Tables)

3 Months Ended

Mar. 31, 2017

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

Schedule of Stock-based Compensation Expense

Total stock-based compensation expense related to options, restricted stock awards, employee stock purchases, restricted stock units and stock purchase rights granted were allocated as follows (in thousands):

	Three Months Ended March 31,
	2017		2016
Cost of revenue	$	1,024	$	793
Research and development	9,587		7,457
Sales and marketing	3,456		3,647
General and administrative	2,372		1,463
Total stock-based compensation	$	16,439	$	13,360

Schedule of Option and RSA Activity

The following table summarizes the option and RSA (Restricted Stock Award) activity under our equity stock plans and related information:

	Options and RSAs Outstanding
	Number of Shares Underlying Outstanding Options and RSAs  (in thousands)		Weighted- Average Exercise Price per Share		Weighted- Average Remaining Contractual Term (Years) of Stock Options	Aggregate Intrinsic Value of Stock Options Outstanding (in thousands)
Outstanding—December 31, 2016	9,509		$	28.79	6.9	$	646,394
Options granted	165		95.51
Options exercised	(882	)	15.32
Options canceled	(223	)	32.10
Outstanding—March 31, 2017	8,569		$	31.38	6.8	$	864,597
Vested and exercisable—March 31, 2017	3,144		$	16.75	6.0	$	363,194
Vested and expected to vest—March 31, 2017	8,569		$	31.38	6.8	$	864,597

Schedule of Nonvested Restricted Stock Units Activity

A summary of the RSU activity under our stock plans during the reporting period and a summary of information related to RSUs expected to vest are presented below (in thousands, except per share and year amounts):

	Number of Shares		Weighted- Average Grant Date Fair Value Per Share		Weighted-Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value
Unvested balance—December 31, 2016	1,375		$	74.23	1.8	$	133,081
RSUs granted	283		109.51
RSUs vested	(119	)	72.85
RSUs forfeited	(20	)	69.30
Unvested balance—March 31, 2017	1,519		$	80.97	1.8	$	200,947
Vested and expected to vest—March 31, 2017	1,519		$	80.97	1.8	$	200,947

Schedule of Shares Available For Grant

The following table presents the stock activity and the total number of shares available for grant as of March 31, 2017 (in thousands):

	Number of Shares
Balance—December 31, 2016	11,754
Authorized	2,124
Options granted	(165	)
RSUs granted	(283	)
Options canceled	223
Options repurchased	2
RSUs forfeited	20
Shares traded for taxes	5
Balance—March 31, 2017	13,680