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	Oct. 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	$ 132,390	3,318
Gross unrealized losses	(458)	(1)
Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Fair value	5,809	17,626
Gross unrealized losses	0	(2)
Corporate notes and bonds
Schedule of Available-for-sale Securities [Line Items]
Fair value	448,241	29,558
Gross unrealized losses	(1,609)	(23)
Foreign government bonds
Schedule of Available-for-sale Securities [Line Items]
Fair value	16,687	2,679
Gross unrealized losses	(57)	$ (2)
U.S. agency obligations
Schedule of Available-for-sale Securities [Line Items]
Fair value	24,924
Gross unrealized losses	(50)
U.S. treasury securities
Schedule of Available-for-sale Securities [Line Items]
Fair value	207,733
Gross unrealized losses	$ (397)