Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2020	Oct. 31, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (17,078)	$ (4,309)	$ (47,297)	$ (31,811)
Other comprehensive income (loss), net of tax:
Net unrealized gains (losses) on investments	(224)	140	595	588
Other comprehensive income (loss), net of tax	(224)	140	595	588
Comprehensive loss	$ (17,302)	$ (4,169)	$ (46,702)	$ (31,223)