CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2020	Jul. 31, 2019
Income Statement [Abstract]
Revenue	$ 192,293	$ 172,549	$ 375,854	$ 335,523
Cost of revenue	55,334	53,872	109,329	102,556
Gross profit	136,959	118,677	266,525	232,967
Operating expenses:
Research and development	50,115	49,693	103,229	95,937
Sales and marketing	67,757	80,405	140,507	159,225
General and administrative	26,597	24,856	54,539	49,463
Total operating expenses	144,469	154,954	298,275	304,625
Loss from operations	(7,510)	(36,277)	(31,750)	(71,658)
Interest expense, net	(1,765)	(335)	(3,132)	(403)
Other income (loss), net	1,952	693	2,216	(187)
Loss before provision for income taxes	(7,323)	(35,919)	(32,666)	(72,248)
Provision for income taxes	333	315	540	814
Net loss	$ (7,656)	$ (36,234)	$ (33,206)	$ (73,062)
Net loss per share, basic and diluted	$ (0.05)	$ (0.25)	$ (0.22)	$ (0.50)
Weighted-average shares used to compute net loss per share, basic and diluted	154,732	147,032	153,353	146,205