CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2018	Oct. 31, 2017
Statement of Comprehensive Income [Abstract]
Net loss	$ (31,320)	$ (24,216)	$ (91,730)	$ (69,985)
Other comprehensive income (loss), net of tax:
Unrealized gain (loss) on available-for-sale securities	9	4	(43)	(33)
Foreign currency translation adjustments	(49)	21	(178)	181
Other comprehensive income (loss)	(40)	25	(221)	148
Total comprehensive loss	$ (31,360)	$ (24,191)	$ (91,951)	$ (69,837)