CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Apr. 30, 2017	Apr. 30, 2016
Income Statement [Abstract]
Revenue	$ 117,222	$ 90,155
Cost of revenue	32,723	27,859
Gross profit	84,499	62,296
Operating expenses:
Research and development	33,534	26,907
Sales and marketing	70,663	59,472
General and administrative	20,281	14,509
Total operating expenses	124,478	100,888
Loss from operations	(39,979)	(38,592)
Interest expense, net	(279)	(176)
Other income, net	16	441
Loss before provision for income taxes	(40,242)	(38,327)
(Benefit) provision for income taxes	(156)	248
Net loss	$ (40,086)	$ (38,575)
Net loss per common share, basic and diluted	$ (0.30)	$ (0.31)
Weighted-average shares used to compute net loss per share, basic and diluted	131,469	124,932