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	Apr. 30, 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	$ 30,844	3,318
Gross unrealized losses	(49)	(1)
Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Fair value	33,342	17,626
Gross unrealized losses	(5)	(2)
Corporate notes and bonds
Schedule of Available-for-sale Securities [Line Items]
Fair value	174,182	29,558
Gross unrealized losses	(209)	(23)
Foreign government bonds
Schedule of Available-for-sale Securities [Line Items]
Fair value	12,097	2,679
Gross unrealized losses	(9)	$ (2)
U.S. treasury securities
Schedule of Available-for-sale Securities [Line Items]
Fair value	7,479
Gross unrealized losses	$ (8)