Equity Incentive Plans (Tables)

12 Months Ended

Jan. 31, 2020

Share-based Payment Arrangement [Abstract]

The following table summarizes stock option and RSU award activity for the 2008 and 2016 Plans (in thousands, except share and per share data and years):



			Options Outstanding
	Shares Available for Grant		Shares		Weighted- Average Exercise Price Per Share		Weighted- Average Remaining Contractual Term (In Years)	Aggregate Intrinsic Value
Balance - January 31, 2018	4,636,564		12,637,435		$	7.63	7.7	$	246,227
Authorized	2,528,778		—		—
Options exercised	—		(3,144,202	)	7.06
Early exercised shares repurchased	35,668		—		—
Options forfeited and expired	872,223		(872,223	)	8.40
RSUs granted	(2,134,844	)	—
RSUs forfeited and canceled	128,687		—
Balance - January 31, 2019	6,067,076		8,621,010		7.75		6.7	729,392
Authorized	2,716,090		—		—
Options exercised	—		(2,163,361	)	7.76
Early exercised shares repurchased	5,677		—		—
Options forfeited and expired	278,650		(278,650	)	11.28
RSUs granted	(2,347,359	)	—
RSUs forfeited and canceled	306,641		—
Balance - January 31, 2020	7,026,775		6,178,999		$	7.60	5.7	$	965,860
Options vested and exercisable - January 31, 2019			5,342,183		$	6.95	6.0	$	456,275
Options vested and exercisable - January 31, 2020			4,693,273		$	7.08	5.4	$	736,034
Options vested and exercisable - Stock options vested and expected to vest -January 31, 2020			6,178,999		$	7.60	5.7	$	965,860

Schedule of RSU activity

The following table summarizes RSU activity for the year ended January 31, 2020:



	Shares		Weighted-Average Grant Date Fair Value per RSU
Unvested - January 31, 2018	245,746		$	26.20
RSUs granted	2,134,844		54.53
RSUs vested	(263,129	)	42.38
RSUs forfeited and canceled	(128,687	)	42.08
Unvested - January 31, 2019	1,988,774		54.22
RSUs granted	2,347,359		128.25
RSUs vested	(748,061	)	65.96
RSUs forfeited and canceled	(306,641	)	77.59
Unvested - January 31, 2020	3,281,431		$	102.30

Schedule of stock option valuation assumptions

The fair value of stock options granted was estimated on the date of grant using the Black-Scholes option pricing model with the following assumptions:



	Years Ended January 31,
	2020	2019	2018
Expected term (in years)	*	*	5.85 - 6.20
Expected volatility	*	*	41.2% - 45.7%
Risk-free interest rate	*	*	1.8% - 2.4%
Dividend yield	*	*	0%

* No stock options were granted during the years ended January 31, 2020 and 2019.

Schedule of ESPP valuation assumptions

The fair value of the purchase rights granted under the 2017 ESPP was estimated on the first day of the offering period using the Black-Scholes option-pricing model with the following assumptions:



	Years Ended January 31,
	2020	2019
Expected term (in years)	0.49 - 0.54	0.49 - 0.54
Expected volatility	42% - 48%	29% - 54%
Risk-free interest rate	1.6% - 2.2%	2.1% - 2.5%
Dividend yield	0%	0%

Schedule of stock-based compensation expense recognized in consolidated statements of operations

Total stock-based compensation expense recognized in the Company’s consolidated statements of operations is as follows (in thousands):



	Years Ended January 31,
	2020		2019		2018
Cost of revenue—subscription	$	4,996	$	2,047	$	730
Cost of revenue—services	3,047		1,239		462
Sales and marketing	26,640		11,059		6,364
Research and development	26,686		11,687		5,752
General and administrative	14,407		11,371		7,927
Total stock-based compensation expense	$	75,776	$	37,403	$	21,235