Stockholders' Equity (Tables)

12 Months Ended

Jan. 31, 2016

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

A summary of stock option activity for fiscal 2016 is presented below

						Weighted
				Weighted		average
				average		remaining		Aggregate
	Number			exercise		contractual		intrinsic
	of shares			price		term (in years)		value
Options outstanding at January 31, 2015		20,233,620		$	4.18		7.7	$	498,862,568
Options granted		619,800			26.91
Options exercised		(2,034,581	)		2.90
Options forfeited/cancelled		(269,137	)		9.04
Options outstanding at January 31, 2016		18,549,702		$	5.01		6.8	$	359,306,108
Options vested and exercisable at January 31, 2016		5,359,310		$	3.51		6.1	$	111,640,103
Options vested and exercisable at January 31, 2016 and expected to vest thereafter		17,784,060		$	5.00		6.8	$	344,779,212

Summary of RSU Activity

A summary of RSU activity for fiscal 2016 is presented below:

				Weighted
	Unreleased			average
	Restricted			grant date
	Stock Units			fair value
Balance at January 31, 2015		965,972		$	27.48
RSUs granted		1,996,000			26.59
RSUs vested		(446,515	)		27.28
RSUs forfeited/cancelled		(296,032	)		26.88
Balance at January 31, 2016		2,219,425		$	26.80

Schedule of Weighted-Average Assumptions Used to Estimate Fair Value of Options Granted

The following table presents the weighted-average assumptions used to estimate the fair value of our stock options granted during the periods presented:

	For the fiscal year ended
	2016		2015		2014
Volatility	45% – 46%		48% – 50%		42% – 50%
Expected term (in years)	5.50 – 6.32		6.00 – 6.32		6.32 – 8.23
Risk-free interest rate	1.69% – 1.84%		1.75% – 1.94%		1.03% – 2.09%
Dividend yield		0%		0%		0%

Schedule of Weighted-Average Assumptions Used to Calculate Out Stock-Based Compensation for Stock Purchase under ESPP

The following table presents the weighted-average assumptions used to calculate our stock-based compensation for the stock purchases under the ESPP:

Volatility						44%
Expected term (in years)						0.58
Risk-free interest rate						0.10%
Dividend yield						0%