CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Income Statement [Abstract]
Revenue	$ 622,658	$ 330,517	$ 151,478
Cost of revenue	115,396	61,001	30,780
Gross profit	507,262	269,516	120,698
Operating expenses:
Research and development	67,079	33,014	15,733
Sales and marketing	340,646	185,821	82,707
General and administrative	86,841	44,514	27,091
Total operating expenses	494,566	263,349	125,531
Income (loss) from operations	12,696	6,167	(4,833)
Interest income and other, net	13,666	2,182	1,315
Total	26,362	8,349	(3,518)
Provision for income taxes	1,057	765	304
Net income (loss)	25,305	7,584	(3,822)
Distributed earnings attributable to participating securities	0	0	(4,405)
Undistributed earnings attributable to participating securities	(3,555)	(7,584)	0
Net income (loss) attributable to common stockholders	$ 21,750	$ 0	$ (8,227)
Net income (loss) per share attributable to common stockholders:
Basic (in dollars per share)	$ 0.09	$ 0.00	$ (0.11)
Diluted (in dollars per share)	$ 0.09	$ 0.00	$ (0.11)
Weighted-average shares used in computing net income (loss) per share attributable to common stockholders:
Basic (in shares)	233,641,336	84,483,094	78,119,865
Diluted (in shares)	254,298,014	116,005,681	78,119,865