Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2017	Oct. 31, 2016	Oct. 31, 2017	Oct. 31, 2016
Statement of Comprehensive Income [Abstract]
Net loss	$ (33,778)	$ (21,931)	$ (89,681)	$ (65,285)
Net change in unrealized gains (losses) on available-for-sale securities	(58)	(20)	(70)	14
Foreign currency translation adjustments	(81)	(89)	168	(144)
Other comprehensive income (loss)	(139)	(109)	98	(130)
Comprehensive loss	$ (33,917)	$ (22,040)	$ (89,583)	$ (65,415)