Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2019	Jul. 31, 2018
Statement of Comprehensive Income [Abstract]
Net loss	$ (42,980)	$ (39,207)	$ (94,946)	$ (65,169)	[1]
Other comprehensive income (loss):
Net change in unrealized losses on available-for-sale securities	194	77	389	(48)
Foreign currency translation adjustments	(1,390)	(379)	(1,723)	(823)
Other comprehensive loss	(1,196)	(302)	(1,334)	(871)
Comprehensive loss	$ (44,176)	$ (39,509)	$ (96,280)	$ (66,040)

[1] Adjusted for adoption of ASC 842, Leases. See Note 2.