Equity Award Plan Activities (Tables)

9 Months Ended

Sep. 30, 2016

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 September 30,				Nine Months Ended September 30,
	2016		2015		2016		2015
Cost of revenue	$	955	$	786	$	2,616	$	2,206
Research and development	8,010		7,037		23,062		18,344
Sales and marketing	3,947		2,864		11,374		8,138
General and administrative	2,204		1,591		5,656		3,637
Total stock-based compensation	$	15,116	$	12,278	$	42,708	$	32,325

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, 2015	11,630		$	24.49	7.6	$	620,802
Options granted	440		56.88
Options exercised	(1,583	)	9.85
Options canceled	(314	)	30.22
Outstanding—September 30, 2016	10,173		$	28.00	7.1	$	580,661
Vested and exercisable—September 30, 2016	3,685		$	14.38	6.3	$	260,514
Vested and expected to vest—September 30, 2016	9,658		$	27.39	7.1	$	557,170

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, 2015	893		$	70.14	1.9	$	69,509
RSUs granted	440		63.80
RSUs vested	(178	)	69.66
RSUs forfeited	(72	)	67.06
Unvested balance—September 30, 2016	1,083		$	67.85	1.7	$	92,120
Vested and expected to vest—September 30, 2016	1,015		$	67.86	1.7	$	86,357

Schedule of Shares Available For Grant

The following table presents the stock activity and the total number of shares available for grant as of September 30, 2016 (in thousands):

	Number of Shares
Balance—December 31, 2015	10,495
Authorized	2,044
Options granted	(440	)
RSUs granted	(440	)
Options canceled	314
Options repurchased	5
RSUs forfeited	72
Shares traded for taxes	11
Balance—September 30, 2016	12,061