Stockholders' Equity (Tables)

9 Months Ended

Oct. 31, 2016

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

A summary of stock option activity for the nine months ended October 31, 2016 is as follows:

						Weighted
				Weighted		average
				average		remaining		Aggregate
	Number			exercise		contractual		intrinsic
	of shares			price		term (in years)		value
Options outstanding at January 31, 2016		18,549,702		$	5.01		6.8	$	359,306,108
Options granted		1,265,000			27.51
Options exercised		(2,537,421	)		3.15
Options forfeited/cancelled		(232,919	)		4.34
Options outstanding at October 31, 2016		17,044,362		$	6.97		6.5	$	543,566,597
Options vested and exercisable at October 31, 2016		5,673,711		$	5.06		5.9	$	191,721,450
Options vested and exercisable at October 31, 2016 and expected to vest thereafter		16,439,091		$	6.90		6.5	$	525,406,590

Summary of Restricted Stock Unit (RSU) Activity

A summary of restricted stock unit (RSU) activity for the nine months ended October 31, 2016 is as follows:

				Weighted
	Unreleased			average
	Restricted			grant date
	Stock Units			fair value
Balance at January 31, 2016		2,219,425		$	26.80
RSUs granted		2,219,333			28.79
RSUs vested		(690,642	)		26.76
RSUs forfeited/cancelled		(301,950	)		26.58
Balance at October 31, 2016		3,446,166		$	28.11

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

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

	Three Months Ended October 31,			Nine Months Ended October 31,
	2016		2015	2016		2015
Volatility		45%	—	45% – 46%		45% – 46%
Expected term (in years)		6.35	—	6.31 – 7.56		5.50 – 6.32
Risk-free interest rate	1.51% – 1.63%		—	1.48% – 1.67%		1.69% – 1.84%
Dividend yield		0%	—		0%		0%