CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands		12 Months Ended
		Jan. 31, 2019	Jan. 31, 2018	[2]	Jan. 31, 2017	[2]
Statement of Comprehensive Income [Abstract]
Net loss	[1]	$ (99,011)	$ (83,973)	[3]	$ (70,063)	[3]
Other comprehensive income (loss), net of tax:
Unrealized gain (loss) on available-for-sale securities	[1]	94	(88)		18
Foreign currency translation adjustments	[1]	(109)	293		(31)
Other comprehensive income (loss)		(15)	205		(13)
Total comprehensive loss		$ (99,026)	$ (83,768)		$ (70,076)

[1] See Note 2 for a summary of adjustments.

[2] See Note 2 for a summary of adjustments.

[3] See Note 2 for a summary of adjustments.