CASH AND CASH EQUIVALENTS, INVESTMENTS, AND FAIR VALUE MEASUREMENTS - Schedule of Fair Value, Assets Measured on Recurring Basis (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jul. 31, 2026	Jul. 31, 2026	Jan. 31, 2026
Cash and cash equivalents:
Amortized Cost	$ 200,951	$ 200,951	$ 169,627
Short-term investments:
Amortized Cost	454,375	454,375	457,646
Gross Unrealized Gains	135	135	1,396
Gross Unrealized Losses	(213)	(213)	(1)
Estimated Fair Value	454,297	454,297	459,041
Long-term investments:
Amortized Cost			104,227
Gross Unrealized Gains			465
Gross Unrealized Losses			0
Estimated Fair Value			104,692
Total assets measured at fair value, Amortized Cost			731,500
Total assets measured at fair value, Gross Unrealized Gains			1,861
Total assets measured at fair value, Gross Unrealized Losses			(1)
Total assets measured at fair value, Estimated Fair Value	658,015	658,015	733,360
Unrealized losses	600	1,600
Cumulative unrealized losses on marketable equity securities	1,600	1,600
Level 1 | U.S. treasury securities
Short-term investments:
Amortized Cost	268,998	268,998	271,254
Gross Unrealized Gains	95	95	786
Gross Unrealized Losses	(145)	(145)	0
Estimated Fair Value	268,948	268,948	272,040
Long-term investments:
Amortized Cost			45,754
Gross Unrealized Gains			227
Gross Unrealized Losses			0
Estimated Fair Value	2,767	2,767	45,981
Level 2 | Commercial paper
Short-term investments:
Amortized Cost	29,353	29,353
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(9)	(9)
Estimated Fair Value	29,344	29,344
Level 2 | Corporate notes and bonds
Short-term investments:
Amortized Cost	147,524	147,524	177,892
Gross Unrealized Gains	40	40	610
Gross Unrealized Losses	(56)	(56)	0
Estimated Fair Value	147,508	147,508	178,502
Long-term investments:
Amortized Cost			58,473
Gross Unrealized Gains			238
Gross Unrealized Losses			0
Estimated Fair Value			58,711
Level 2 | U.S. agency securities
Short-term investments:
Amortized Cost	8,500	8,500	8,500
Gross Unrealized Gains	0	0	0
Gross Unrealized Losses	(3)	(3)	(1)
Estimated Fair Value	8,497	8,497	8,499
Cash
Cash and cash equivalents:
Amortized Cost	90,988	90,988
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	90,988	90,988
Cash | Level 1
Cash and cash equivalents:
Amortized Cost			124,873
Gross Unrealized Gains			0
Gross Unrealized Losses			0
Estimated Fair Value			124,873
Money market funds | Level 1
Cash and cash equivalents:
Amortized Cost	109,963	109,963	44,754
Gross Unrealized Gains	0	0	0
Gross Unrealized Losses	0	0	0
Estimated Fair Value	109,963	109,963	44,754
Total cash and cash equivalents
Cash and cash equivalents:
Amortized Cost	200,951	200,951	169,627
Gross Unrealized Gains	0	0	0
Gross Unrealized Losses	0	0	0
Estimated Fair Value	$ 200,951	$ 200,951	$ 169,627