Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Revenues [Abstract]
Revenue		$ 794,191	$ 479,941	$ 372,293
Cost of revenue:
Services	[1],[2]	232,502	136,114	158,035
Gross profit	[1],[2]	561,689	343,827	214,258
Operating expenses:
Research and development	[1],[2]	263,566	173,814	215,695
Sales and marketing	[1],[2]	467,541	253,164	287,196
General and administrative	[1],[2]	170,336	110,613	85,539
Total operating expenses	[1],[2]	901,443	537,591	588,430
Loss from operations		(339,754)	(193,764)	(374,172)
Interest income, net		11,687	9,011	5,150
Other income (expense), net		185	(2,478)	1,429
Loss before provision for income taxes		(327,882)	(187,231)	(367,593)
Provision for income taxes		(8,700)	(5,418)	(2,079)
Net loss		$ (336,582)	$ (192,649)	$ (369,672)
Net loss per share, basic and diluted (in dollars per share)		$ (1.20)	$ (1.21)	$ (3.24)
Weighted-average shares used in computing net loss per share, basic and diluted (in shares)		280,772	159,816	114,141
Subscription
Cost of revenue:
Services	[1],[2]	$ 117,739	$ 63,329	$ 70,902
Services
Cost of revenue:
Services	[1],[2]	$ 114,763	$ 72,785	$ 87,133

[1] Amounts include amortization of acquired intangible assets as follows (in thousands):

[2] Amounts include stock-based compensation expense as follows (in thousands):