CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2020	Jul. 31, 2019
Statement of Comprehensive Income [Abstract]
Net loss	$ (64,525)	$ (37,336)	$ (118,492)	$ (70,576)
Other comprehensive loss, net of tax:
Unrealized gain (loss) on available-for-sale securities	(531)	21	317	79
Foreign currency translation adjustment	(398)	(250)	(473)	(237)
Other comprehensive loss	(929)	(229)	(156)	(158)
Total comprehensive loss	$ (65,454)	$ (37,565)	$ (118,648)	$ (70,734)