CASH, CASH EQUIVALENTS AND INVESTMENTS - Available-for-Sale Securities (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2024	Jul. 31, 2023	Jul. 31, 2024	Jul. 31, 2023	Jan. 31, 2024
Cash and Cash Equivalents
Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss, Current, Statement of Financial Position [Extensible Enumeration]	Investments		Investments
Proceeds from sale of debt securities, available-for-sale	$ 0	$ 0	$ 0	$ 0
Amounts of gains or losses reclassified out of other comprehensive income	0	$ 0	0	$ 0
Available-for-sale securities
Amortized Cost	181,793		181,793		$ 105,623
Gross Unrealized Gains	1,208		1,208		568
Gross Unrealized Losses	296		296		307
Fair Value	182,705		182,705		105,884
US Treasury notes
Available-for-sale securities
Amortized cost, Due within one year	25,200		25,200
Amortized cost, Due in one to three years	91,045		91,045		96,217
Amortized Cost, Due in three to five years	55,502		55,502
Gross Unrealized Gains, Due within one year	3		3
Gross Unrealized Gains, Due in one to three years	449		449		568
Gross Unrealized Gains, Due in three to five years	755		755
Gross Unrealized Losses, Due within one year	94		94
Gross Unrealized Losses, Due in one to three years	202		202		230
Fair Value, Due in within one year	25,109		25,109
Fair Value, Due in one to three years	91,292		91,292		96,555
Fair Value, Due in three to five years	56,257		56,257
U.S. corporate debt security
Available-for-sale securities
Amortized cost, Due in one to three years	10,046		10,046		9,406
Gross Unrealized Gains, Due in one to three years	1		1
Gross Unrealized Losses, Due in one to three years					77
Fair Value, Due in one to three years	$ 10,047		$ 10,047		$ 9,329