Financial Instruments and Fair Value - Schedule of Available-for-Sale Securities at Fair Value (Detail) - USD ($) $ in Thousands	Apr. 30, 2021	Jan. 31, 2021
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 214,069	$ 213,583
Unrealized Gains	832	1,226
Unrealized Losses	(40)	(7)
Fair Value	214,861	214,802
Money market funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2,342	171
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	2,342	171
Commercial paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	64,978	66,181
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	64,978	66,181
Corporate bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	99,950	102,108
Unrealized Gains	665	980
Unrealized Losses	(31)	(7)
Fair Value	100,584	103,081
Asset-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	17,000	15,740
Unrealized Gains	105	164
Unrealized Losses	(7)	0
Fair Value	17,098	15,904
U.S. government securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	29,799	29,383
Unrealized Gains	62	82
Unrealized Losses	(2)	0
Fair Value	$ 29,859	$ 29,465

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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