Stockholders' Equity (Deficit) and Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2014

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Disclosure of Share-based Compensation Arrangements by Share-based Payment Award

The Company had the following shares of common stock reserved for issuance upon the exercise or vesting of equity instruments:

(in thousands)	September 30, 2014	December 31, 2013
Stock options outstanding	27,518	26,724
Restricted stock units outstanding	3,900	270
Stock options, restricted stock and RSUs available for future grants	13,403	1,306
	44,821	28,300

Schedule of Share-based Compensation, Stock Options, Activity

A summary of the Company’s stock option activity and related information is as follows:

	Options outstanding
(shares in thousands)	Shares		Weighted- average exercise price		Weighted- average grant date fair value		Total intrinsic value of options exercised (in thousands)		Weighted- average remaining contractual term (in years)	Aggregate intrinsic value (in thousands)
Outstanding at December 31, 2013:	26,724		$	2.47					7.55	$	367,395
Granted	5,058		19.91		$	10.58
Exercised	(3,932	)	0.92				$	84,219
Forfeited/Cancelled	(332	)	11.77
Outstanding at September 30, 2014:	27,518		$	5.79					7.38	$	2,419,222
Exercisable at September 30, 2014	19,356		$	1.49					6.70	$	1,784,809
Vested and expected to vest at September 30, 2014	26,546		$	5.45					7.33	$	2,342,529

Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding and Exercisable

The following is a further breakdown of the options outstanding and exercisable at September 30, 2014:

	Options outstanding				Options exercisable
(options in thousands)	Options outstanding	Weighted average remaining contractual life (in years)	Weighted average exercise price		Options exercisable	Weighted average exercise price
Range of exercise prices
$ 0.18–0.66	8,901	6.37	$	0.62	8,814	$	0.62
0.76	8,712	6.72	0.76		8,310	0.76
1.52–2.96	1,767	7.31	1.91		1,147	1.87
8.30	504	8.05	8.30		243	8.30
13.72	871	8.40	13.72		347	13.72
15.40	572	8.69	15.40		204	15.40
15.59	431	8.90	15.59		122	15.59
16.19	761	9.14	16.19		13	16.19
16.22	1,125	9.33	16.22		—	—
16.39	651	9.52	16.39		14	16.39
18.40	2,800	9.68	18.40		142	18.40
38.84–41.98	192	9.81	40.85		—	—
43.96–65.23	231	9.84	49.40		—	—
$ 0.18–65.23	27,518	7.38	5.79		19,356	1.49

Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity

The following table summarizes the activities of the Company’s restricted stock and early-exercised stock options subject to repurchase:

(in thousands except for weighted average grant date fair value)	Shares		Weighted- average grant date fair value		Aggregate intrinsic value
Non-vested shares at December 31, 2013	487		$	11.03	$	7,628
Vested	(215	)
Non-vested shares at September 30, 2014	272		$	13.76	$	25,424

Schedule of Share-based Compensation, Restricted Stock Units Award Activity

The following table summarizes the activities of the Company’s RSUs:

(in thousands except for weighted average grant date fair value)	Shares		Weighted- average grant date fair value
Non-vested shares at December 31, 2013	270		$	1.52
Granted	5,147		17.39
Vested	(1,517	)	18.41
Non-vested shares at September 30, 2014	3,900		16.01

Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs

Stock-based compensation expense. The following tables set forth the detailed allocation of stock-based compensation expense (in thousands):

	Three months ended						Nine months ended
	September 30, 2014			September 30, 2013			September 30, 2014			September 30, 2013
Stock-based compensation expense:
Cost of revenue	$	233		$	153		$	555		$	530
Research and development	2,428			740			5,486			1,737
Sales and marketing	3,225			1,419			6,293			4,077
General and administrative	8,027			408			39,809			1,003
Total stock-based compensation expense	13,913			2,720			52,143			7,347
Total tax benefit recognized	(2,949		)	(293		)	(14,774		)	(838		)
Decrease in net income	$	10,964		$	2,427		$	37,369		$	6,509
Stock-based compensation expense by type of award:
Stock options	$	5,123		$	2,194		$	11,504		$	5,843
ESPP	832			—			873			—
Restricted stock	2,590			526			4,906			1,504
RSUs	5,368			—			34,860			—
Total stock-based compensation expense	13,913			2,720			52,143			7,347
Total tax benefit recognized	(2,949		)	(293		)	(14,774		)	(838		)
Decrease in net income	$	10,964		$	2,427		$	37,369		$	6,509

Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan

Stock-based compensation expense. The following tables set forth the detailed allocation of stock-based compensation expense (in thousands):

	Three months ended						Nine months ended
	September 30, 2014			September 30, 2013			September 30, 2014			September 30, 2013
Stock-based compensation expense:
Cost of revenue	$	233		$	153		$	555		$	530
Research and development	2,428			740			5,486			1,737
Sales and marketing	3,225			1,419			6,293			4,077
General and administrative	8,027			408			39,809			1,003
Total stock-based compensation expense	13,913			2,720			52,143			7,347
Total tax benefit recognized	(2,949		)	(293		)	(14,774		)	(838		)
Decrease in net income	$	10,964		$	2,427		$	37,369		$	6,509
Stock-based compensation expense by type of award:
Stock options	$	5,123		$	2,194		$	11,504		$	5,843
ESPP	832			—			873			—
Restricted stock	2,590			526			4,906			1,504
RSUs	5,368			—			34,860			—
Total stock-based compensation expense	13,913			2,720			52,143			7,347
Total tax benefit recognized	(2,949		)	(293		)	(14,774		)	(838		)
Decrease in net income	$	10,964		$	2,427		$	37,369		$	6,509

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions

The fair value of the Company’s stock options granted to employees, officers and non-employee board members was estimated using the following weighted average assumptions:

	Three months ended		Nine months ended
	September 30, 2014	September 30, 2013	September 30, 2014	September 30, 2013
Dividend yield	None	None	None	None
Expected volatility	54.4% - 55.2%	60.0%	53.9% - 56.0%	56.0% - 60.0%
Risk-free interest rate	1.8% - 2.0%	1.6% - 2.0%	1.7% - 2.0%	0.8% - 2.0%
Expected term (years)	5.5 - 6.1	5.9 - 6.1	5.3 - 6.3	5.3 - 6.1
Estimated annual forfeiture rate	5.0%	6.0%	5.0% - 6.0%	6.0%
Weighted average fair value at grant date	$24.13	$9.11	$10.58	$8.20

Schedule of Share-based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions

The fair value of the Company’s ESPP shares to be issued to employees was estimated using the following weighted average assumptions:

	Three months ended	Nine months ended
	September 30, 2014	September 30, 2014
Dividend yield	None	None
Expected volatility	47.0%	47.0%
Risk-free interest rate	0.1%	0.1%
Expected term (years)	0.6	0.6
Weighted average fair value at purchase date	$7.16	$7.16

Restricted Stock Units (RSUs) [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Schedule of Share-based Payment Award, Equity Instruments Other Than Options, Valuation Assumptions [Table Text Block]

The Company estimated the fair value of these shares using a Monte Carlo valuation model with the following weighted-average assumptions:

Dividend yield	None
Expected volatility	50.9%
Risk-free interest rate	2.69%
Expected term (years)	10.0
Grant date fair value of underlying shares	$18.40