CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Unaudited) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2016	Jul. 31, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net loss		$ (38,102)	$ (50,175)	$ (76,677)	$ (97,458)
Other comprehensive income (loss):
Changes in foreign currency translation adjustment	[1]	(49)	(21)	65	(28)
Net change in unrealized gain (loss) on available-for-sale investments	[1]	1	(9)	3	(7)
Other comprehensive income (loss):	[1]	(48)	(30)	68	(35)
Comprehensive loss		$ (38,150)	$ (50,205)	$ (76,609)	$ (97,493)

[1] Tax effect was not material