Stock-Based Compensation (Tables)

3 Months Ended

Apr. 30, 2017

Summary of Stock Option Activity Under Equity Incentive Plans and Related Information

The following table summarizes the stock option activity under the equity incentive plans and related information:

	SharesSubject to Options Outstanding					Weighted-Average
				Weighted-		Remaining
				Average Exercise		Contractual Life		Aggregate
	Shares			Price		(Years)		Intrinsic Value
								(in thousands)
Balance as of January 31, 2017		12,318,800		$	7.44
Options granted		1,030,000			16.67
Option exercised		(531,910	)		4.62
Options forfeited/cancelled		(65,575	)		15.15
Balance as of April 30, 2017		12,751,315		$	8.27		6.50	$	115,138
Vested and expected to vest as of April 30, 2017		12,600,593		$	8.19		6.47	$	114,682
Exercisable as of April 30, 2017		9,160,781		$	5.91		5.68	$	104,276

Summary of Restricted Stock Unit Activity Under Equity Incentive Plans and Related Information

The following table summarizes the restricted stock unit activity under the equity incentive plans and related information:

	Number of			Weighted-
	Restricted			Average
	Stock Units			Grant Date
	Outstanding			Fair Value
Unvested balance - January 31, 2017		11,822,316		$	14.67
Granted		3,782,656			16.69
Vested, net of shares withheld for employee    payroll taxes		(792,847	)		13.43
Forfeited/cancelled, including shares withheld for    employee payroll taxes		(837,932	)		14.11
Unvested balance - April 30, 2017		13,974,193		$	15.32

Summary of Components of Stock-Based Compensation Expense

The following table summarizes the components of stock-based compensation expense recognized in the consolidated statements of operations (in thousands):

	Three Months Ended
	April 30,
	2017		2016
Cost of revenue	$	2,468	$	1,512
Research and development		9,160		6,524
Sales and marketing		7,740		5,230
General and administrative		3,578		2,823
Total stock-based compensation	$	22,946	$	16,089

Summary of Estimated Fair Value of Employee Stock Options

We estimated the fair value of employee stock options and 2015 ESPP purchase rights using generally a Black-Scholes option pricing model with the following assumptions:

	Three Months Ended
	April 30,
	2017					2016
Employee Stock Options
Expected term (in years)					6.0					6.0
Risk-free interest rate		2.1	%	-	2.4%					1.3%
Volatility		39	%	-	40%					43%
Dividend yield					0%					0%
Employee Stock Purchase Plan
Expected term (in years)		0.5		-	2.0	0.5			-	2.0
Risk-free interest rate		0.9	%	-	1.4%		0.5	%	-	0.9%
Volatility		28	%	-	43%		46	%	-	60%
Dividend yield					0%					0%

Restricted Stock Awards

Summary of Restricted Stock Award Activity Under Equity Incentive Plans and Related Information

The following table summarizes the restricted stock activity under the equity incentive plans and related information:

	Number of			Weighted-
	Restricted			Average
	Stock			Grant Date
	Outstanding			Fair Value
Unvested balance - January 31, 2017		5,842		$	11.86
Vested, net of shares withheld for employee    payroll taxes		(2,968	)		17.67
Forfeited/cancelled, including shares withheld for    employee payroll taxes		—			—
Unvested balance - April 30, 2017		2,874		$	5.85