Short-Term Investments - Schedule of Fair Values and Gross Unrealized Loss Position of Available-for-Sale Securities Aggregated by Investment Category (Detail) - USD ($) $ in Thousands	Jul. 31, 2021	Jan. 31, 2021
Certificates of deposits
Schedule of Available-for-sale Securities [Line Items]
Fair value		$ 3,749
Gross unrealized losses		(2)
Asset-backed securities
Schedule of Available-for-sale Securities [Line Items]
Fair value	$ 37,835	3,318
Gross unrealized losses	(46)	(1)
Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Fair value	17,794	17,626
Gross unrealized losses	(2)	(2)
Corporate notes and bonds
Schedule of Available-for-sale Securities [Line Items]
Fair value	173,830	29,558
Gross unrealized losses	(226)	(23)
Foreign government bonds
Schedule of Available-for-sale Securities [Line Items]
Fair value	13,614	2,679
Gross unrealized losses	(6)	$ (2)
U.S. treasury securities
Schedule of Available-for-sale Securities [Line Items]
Fair value	83,192
Gross unrealized losses	$ (7)