CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Unaudited) - USD ($) $ in Thousands		3 Months Ended
		Apr. 30, 2017	Apr. 30, 2016
Statement Of Income And Comprehensive Income [Abstract]
Net loss		$ (40,086)	$ (38,575)
Other comprehensive income:
Changes in foreign currency translation adjustment	[1]	29	114
Net change in unrealized gain on available-for-sale investments	[1]		2
Other comprehensive income:	[1]	29	116
Comprehensive loss		$ (40,057)	$ (38,459)

[1] Tax effect was not material