CASH AND CASH EQUIVALENTS, INVESTMENTS, AND FAIR VALUE MEASUREMENTS - Schedule of Fair Value, Assets Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Jul. 31, 2025	Jan. 31, 2025	Jul. 31, 2024
Cash and cash equivalents:
Amortized Cost	$ 278,005	$ 186,574	$ 278,005
Short-term investments:
Amortized Cost	531,849	534,391
Gross Unrealized Gains	1,039	1,022
Gross Unrealized Losses	(70)	(82)
Estimated Fair Value	532,818	535,331
Long-term investments:
Amortized Cost	316,988	395,444
Gross Unrealized Gains	306	1,360
Gross Unrealized Losses	(393)	(597)
Estimated Fair Value	316,901	396,207
Total assets measured at fair value, Amortized Cost	1,126,842	1,116,408
Total assets measured at fair value, Gross Unrealized Gains	1,345	2,385
Total assets measured at fair value, Gross Unrealized Losses	(463)	(681)
Total assets measured at fair value, Estimated Fair Value	1,127,724	1,118,112
Cash
Cash and cash equivalents:
Amortized Cost	99,118
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Estimated Fair Value	99,118
Total cash and cash equivalents
Cash and cash equivalents:
Amortized Cost	278,005	186,573
Gross Unrealized Gains	0	3
Gross Unrealized Losses	0	(2)
Estimated Fair Value	278,005	186,574
Level 1 | U.S. treasury securities
Short-term investments:
Amortized Cost	233,244	208,918
Gross Unrealized Gains	513	284
Gross Unrealized Losses	(44)	(74)
Estimated Fair Value	233,713	209,128
Long-term investments:
Amortized Cost	175,835	208,104
Gross Unrealized Gains	208	787
Gross Unrealized Losses	(145)	(203)
Estimated Fair Value	175,898	208,688
Level 1 | Cash
Cash and cash equivalents:
Amortized Cost		94,728
Gross Unrealized Gains		0
Gross Unrealized Losses		0
Estimated Fair Value		94,728
Level 1 | Money market funds
Cash and cash equivalents:
Amortized Cost	178,887	61,962
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	178,887	61,962
Level 2 | Commercial paper
Short-term investments:
Amortized Cost	4,972	24,606
Gross Unrealized Gains	0	1
Gross Unrealized Losses	(1)	(2)
Estimated Fair Value	4,971	24,605
Level 2 | Corporate notes and bonds
Short-term investments:
Amortized Cost	269,726	238,610
Gross Unrealized Gains	514	586
Gross Unrealized Losses	(25)	(6)
Estimated Fair Value	270,215	239,190
Long-term investments:
Amortized Cost	132,653	173,882
Gross Unrealized Gains	98	573
Gross Unrealized Losses	(204)	(331)
Estimated Fair Value	132,547	174,124
Level 2 | U.S. agency securities
Short-term investments:
Amortized Cost	23,907	62,257
Gross Unrealized Gains	12	151
Gross Unrealized Losses	0	0
Estimated Fair Value	23,919	62,408
Long-term investments:
Amortized Cost	8,500	13,458
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(44)	(63)
Estimated Fair Value	$ 8,456	13,395
Level 2 | U.S. treasury securities
Cash and cash equivalents:
Amortized Cost		9,969
Gross Unrealized Gains		3
Gross Unrealized Losses		0
Estimated Fair Value		9,972
Level 2 | Commercial paper
Cash and cash equivalents:
Amortized Cost		19,914
Gross Unrealized Gains		0
Gross Unrealized Losses		(2)
Estimated Fair Value		$ 19,912