Equity Award Plan Activities (Tables)

6 Months Ended

Jun. 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 June 30,				Six Months Ended June 30,
	2016		2015		2016		2015
Cost of revenue	$	868	$	784	$	1,661	$	1,420
Research and development	7,595		6,379		15,052		11,307
Sales and marketing	3,780		2,865		7,427		5,274
General and administrative	1,989		1,180		3,452		2,046
Total stock-based compensation	$	14,232	$	11,208	$	27,592	$	20,047

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	(825	)	7.71
Options canceled	(232	)	29.16
Outstanding—June 30, 2016	11,013		$	26.94	7.3	$	420,519
Vested and exercisable—June 30, 2016	4,021		$	13.25	6.4	$	207,297
Vested and expected to vest—June 30, 2016	10,449		$	26.29	7.3	$	405,623

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	369		61.81
RSUs vested	(130	)	69.02
RSUs forfeited	(56	)	67.29
Unvested balance—June 30, 2016	1,076		$	67.57	1.9	$	69,302
Vested and expected to vest—June 30, 2016	1,006		$	67.60	1.8	$	64,766

Schedule of Shares Available For Grant

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

	Number of Shares
Balance—December 31, 2015	10,495
Authorized	2,044
Options granted	(440	)
RSUs granted	(369	)
Options canceled	232
Options repurchased	5
RSUs forfeited	56
Shares traded for taxes	9
Balance—June 30, 2016	12,032