Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2014

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,
	2014		2013		2014		2013
Cost of revenue	$	480	$	107	$	992	$	257
Research and development	4,304		1,319		10,298		3,449
Sales and marketing	2,387		765		5,746		1,859
General and administrative	911		393		2,533		834
Total stock-based compensation	$	8,082	$	2,584	$	19,569	$	6,399

Schedule of Stock Option Valuation Assumptions

For the three and nine months ended September 30, 2014 and 2013, the fair value of each stock option granted under the 2011 Plan was estimated on the date of grant using the Black-Scholes option pricing model with the following assumptions and fair value per share:  

	Three Months Ended September 30,				Nine Months Ended September 30,
	2014		2013		2014		2013
Expected term (in years)	6.2		6.7		7.6		6.6
Risk-free interest rate	1.9	%	2.2	%	2.3	%	1.7	%
Expected volatility	49.1	%	50.5	%	47.8	%	50.8	%
Dividend rate	—	%	—	%	—	%	—	%

Schedule of ESPP Valuation Assumptions

There were no stock purchases under the ESPP during the three and nine months ended September 30, 2014.  The following table summarizes the assumptions relating to our ESPP:

	Three Months Ended September 30,			Nine Months Ended September 30,
	2014		2013	2014		2013
Expected term (in years)	1.4		N/A	1.4		N/A
Risk-free interest rate	0.3	%	N/A	0.3	%	N/A
Expected volatility	36.3	%	N/A	36.3	%	N/A
Dividend rate	—	%	N/A	—	%	N/A

Schedule of Option and RSA Activity

The following table summarizes the option and RSA (Restricted Stock Award) activity under the 2004 Plan and 2011 Plan and related information:

			Options and RSAs Outstanding
	Shares Available for Grant (in thousands)		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, 2013	8,941		11,245		$	6.82	8.8	$	254,319
Authorized	6,510
Options granted	(3,537	)	3,483		33.32
Options exercised	—		(244	)	7.6
Options canceled	507		(507	)	11.19
Early exercised shares repurchased	26		—		4.05
Outstanding—September 30, 2014	12,447		13,977		$	13.25	8.4	$	1,047,415
Vested and exercisable—September 30, 2014			3,661		$	4.67	7.5	$	306,260
Vested and expected to vest—September 30, 2014			12,338		$	12.20	8.3	$	939,302

Schedule of Stock Options Outstanding and Vested and Exercisable by Exercise Price

Under the 2004 Plan and 2011 Plan, the options outstanding and vested and exercisable by exercise price at September 30, 2014 are as follows:

	Options Outstanding and Exercisable				Options Vested and Exercisable
Range of Exercise Price	Number of Shares Underlying Outstanding Options (in thousands)	Weighted- Average Remaining Contractual Life (Years)	Weighted- Average Exercise Price per Share		Number of Shares Underlying Outstanding Options  (in thousands)	Weighted- Average Exercise Price per Share
$3.33 - $4.16	4,076	7.2	$	3.65	2,463	$	3.6
$4.18 - $4.92	2,123	8.1	4.56		618	4.73
$7.76 - $8.77	1,971	8.6	8.26		447	8.29
$10.18	1,886	9.0	10.18		120	10.18
$22.49	1,041	9.2	22.49		4	22.49
$30.67	1,658	9.4	30.67		2	30.47
$34.12 - $38.00	1,072	9.6	36.92		7	35.26
$75.00 - $84.00	150	9.9	75.60		—	—
	13,977	8.4	$	13.25	3,661	$	4.67

Schedule of Nonvested Restricted Stock Units Activity

A summary of the activity under our stock plans and changes during the reporting period and a summary of information related to RSUs are presented below (in thousands, except years and per share 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, 2013	—	—		0	—
RSUs granted	54	$	76.76
RSUs vested	—	—
RSUs forfeited/canceled	—	—
Unvested balance—September 30, 2014	54	$	76.76	2.1	$	4,772
RSUs vested and expected to vest—September 30, 2014	54	$	76.76	2.1	$	4,772

Schedule of Restricted Stock Awards Activity

A summary of our RSA activity and related information is as follows (in thousands, except per share amounts):

	Number of RSA’s Outstanding		Weighted- Average Grant Date Fair Value Per Share
Unvested balance—December 31, 2013	142		$	2.42
Vested	(44	)	2.50
Unvested balance—September 30, 2014	98		$	2.50