CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Statement of Comprehensive Income [Abstract]
Net loss	$ (175,522)	$ (99,011)	$ (83,973)
Other comprehensive income (loss), net of tax:
Unrealized gain (loss) on available-for-sale securities	91	94	(88)
Foreign currency translation adjustment	308	(109)	293
Other comprehensive income (loss)	399	(15)	205
Total comprehensive loss	$ (175,123)	$ (99,026)	$ (83,768)