Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Revenue:
Total revenue	$ 973,971	$ 700,969	$ 518,504
Cost of revenue:
Total cost of revenue	243,234	192,421	118,273
Gross profit	730,737	508,548	400,231
Operating expenses:
Sales and marketing	591,379	539,606	277,930
Research and development	185,552	185,968	92,428
General and administrative	147,315	209,297	81,526
Total operating expenses	924,246	934,871	451,884
Loss from operations	(193,509)	(426,323)	(51,653)
Interest expense	(29,254)	(10,844)	(624)
Interest income and other income, net	19,207	8,959	3,135
Loss before provision for (benefit from) income taxes	(203,556)	(428,208)	(49,142)
Provision for (benefit from) income taxes	4,803	(1,750)	3,134
Net loss	$ (208,359)	$ (426,458)	$ (52,276)
Net loss per share attributable to common stockholders, basic and diluted (in usd per share)	$ (1.18)	$ (3.16)	$ (1.66)
Weighted-average number of shares used in computing net loss per share attributable to common stockholders, basic and diluted (in shares)	176,704	135,163	32,294
Other comprehensive income (loss):
Foreign currency translation gains (losses), net of tax	$ (573)	$ (5,626)	$ 6,149
Unrealized gains on investments, net of tax	865	258	0
Other comprehensive income (loss)	292	(5,368)	6,149
Comprehensive loss	(208,067)	(431,826)	(46,127)
Stock-based compensation expense included in costs and expenses:
Stock-based compensation expense	206,404	410,978	29,747
Sales and marketing
Stock-based compensation expense included in costs and expenses:
Stock-based compensation expense	94,863	172,115	9,386
Research and development
Stock-based compensation expense included in costs and expenses:
Stock-based compensation expense	43,211	74,108	4,896
General and administrative
Stock-based compensation expense included in costs and expenses:
Stock-based compensation expense	39,745	122,715	13,578
Subscription
Revenue:
Total revenue	918,463	663,657	484,581
Cost of revenue:
Total cost of revenue	163,931	117,764	83,834
Subscription | Cost of revenue
Stock-based compensation expense included in costs and expenses:
Stock-based compensation expense	12,882	16,182	911
Professional services and other
Revenue:
Total revenue	55,508	37,312	33,923
Cost of revenue:
Total cost of revenue	79,303	74,657	34,439
Professional services and other | Cost of revenue
Stock-based compensation expense included in costs and expenses:
Stock-based compensation expense	$ 15,703	$ 25,858	$ 976