CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2018	Jul. 31, 2017
Statement of Comprehensive Income [Abstract]
Net loss	$ (31,246)	$ (26,079)	$ (60,410)	$ (45,769)
Other comprehensive income (loss), net of tax:
Unrealized loss on available-for-sale securities	30	(28)	(52)	(37)
Foreign currency translation adjustments	(96)	93	(129)	160
Other comprehensive income (loss)	(66)	65	(181)	123
Total comprehensive loss	$ (31,312)	$ (26,014)	$ (60,591)	$ (45,646)