CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Unaudited) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2018	Oct. 31, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net loss		$ (40,196)	$ (42,924)	$ (114,918)	$ (122,295)
Changes in foreign currency translation adjustment	[1]	(89)	(88)	(375)	90
Comprehensive loss		$ (40,285)	$ (43,012)	$ (115,293)	$ (122,205)

[1] Tax effect was not material