CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Unaudited) - USD ($) $ in Thousands		3 Months Ended				6 Months Ended
		Jul. 31, 2019	[1]	Jul. 31, 2018	[2]	Jul. 31, 2019	[1]	Jul. 31, 2018	[2]
Statement Of Income And Comprehensive Income [Abstract]
Net loss		$ (36,234)		$ (38,085)		$ (73,062)		$ (74,722)
Changes in foreign currency translation adjustment	[3]	(164)		(162)		(76)		(286)
Comprehensive loss		$ (36,398)		$ (38,247)		$ (73,138)		$ (75,008)

[1] As reported and disclosed under ASC Topic 842

[2] As reported and disclosed under ASC Topic 840

[3] Tax effect was not material