Stockholders' Equity (Tables)

12 Months Ended

Jan. 31, 2020

Equity [Abstract]

Share of Common Stock Reserved For Future Issuance

We have reserved the following shares of common stock, on an as-if converted basis, for future issuance as follows:

	January 31,
(in thousands)	2020	2019
RSUs outstanding	14,246	17,558
Options issued and outstanding	6,882	13,648
Remaining shares available for future issuance under the Equity Incentive Plans	24,726	17,519
Remaining shares available for future issuance under the ESPP	4,985	3,800
Total shares of common stock reserved	50,839	52,525

Share-based Compensation, Activity

Stock award activity was as follows:

(in thousands)	Year Ended January 31, 2020
Available at beginning of fiscal year	17,519
Awards authorized	8,570
Options canceled/expired	29
RSUs granted	(6,507)
RSUs cancelled	2,336
Shares withheld	2,779
Available at end of fiscal year	24,726

Option activity was as follows:

(in thousands, except per share data and years)	Number of Options	Weighted-Average Exercise Price Per Share		Weighted-Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value
Outstanding at January 31, 2019	13,648	$	12.27	5.38	$	507,371
Exercised	(6,737)	10.09
Canceled/expired	(29)	17.67
Outstanding at January 31, 2020	6,882	$	14.39	5.38	$	441,247
Vested and expected to vest at January 31, 2020	6,836	$	14.37	5.37	$	438,502
Exercisable at January 31, 2020	6,099	$	13.98	5.17	$	393,603

RSU Activity

RSU activity was as follows:

(in thousands, except per share data)	Number of Units	Weighted-Average Grant Date Fair Value
Unvested at January 31, 2019	17,142	$	34.56
Granted	6,507	56.05
Vested	(7,454)	29.91
Canceled	(2,336)	39.72
Unvested at January 31, 2020	13,859	$	46.28

ESPP Valuation Assumptions

We calculated the fair value of the ESPP purchase right using the Black-Scholes option-pricing model, based on the following assumptions:

	Year Ended January 31,
	2020		2019
Risk-free interest rate	1.92 - 2.52 %		2.33 %
Expected dividend yield	—	%	—	%
Expected life of purchase right (in years)	0.5		0.5
Expected volatility	39 - 52 %		40 %
Weighted-average grant date fair value per share	$ 14.88 - 18.56		$ 14.24