Equity Award Plan Activities (Tables)

3 Months Ended

Mar. 31, 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   March 31,
	2016		2015
Cost of revenue	$	793	$	636
Research and development	7,457		4,928
Sales and marketing	3,647		2,409
General and administrative	1,463		866
Total stock-based compensation	$	13,360	$	8,839

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	413		56.33
Options exercised	(288	)	6.58
Options canceled	(161	)	24.34
Outstanding—March 31, 2016	11,594		$	26.08	7.5	$	440,180
Vested and exercisable—March 31, 2016	3,905		$	9.47	6.5	$	210,414
Vested and expected to vest—March 31, 2016	10,982		$	25.39	7.5	$	424,280

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	219		57.56
RSUs vested	(17	)	69.26
RSUs forfeited	(41	)	67.86
Unvested balance—March 31, 2016	1,054		$	67.63	1.9	$	66,495
Vested and expected to vest—March 31, 2016	987		$	67.67	1.8	$	62,254

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, 2016 (in thousands):

	Number of Shares
Balance—December 31, 2015	10,494
Authorized	2,044
Options granted	(413	)
RSUs granted	(219	)
Options canceled	161
Options repurchased	4
RSUs forfeited	41
Balance—March 31, 2016	12,112