CASH, CASH EQUIVALENTS AND INVESTMENTS - Available-for-Sale Securities (Details) - USD ($)	3 Months Ended
	Apr. 30, 2024	Apr. 30, 2023	Jan. 31, 2024
Cash and Cash Equivalents
Interest receivable	$ 800,000
Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss, Current, Statement of Financial Position [Extensible Enumeration]	Investments
Net unrealized holding losses for the Company's AFS securities		$ 1,000,000.0
Proceeds from sale of debt securities, available-for-sale	$ 0	0
Amounts of gains or losses reclassified out of other comprehensive income	0	$ 0
Available-for-sale securities
Amortized Cost	125,639,000		$ 105,623,000
Gross Unrealized Gains			568,000
Gross Unrealized Losses	1,050,000		307,000
Fair Value, Due in within one year	14,865,000
Fair Value	124,589,000		105,884,000
US Treasury notes
Available-for-sale securities
Amortized cost, Due within one year	15,032,000
Amortized cost, Due in one to two years	50,557,000		50,634,000
Amortized Cost, Due in two to three years	50,004,000		45,583,000
Gross Unrealized Gains, Due in one to two years			305,000
Gross Unrealized Gains, Due in two to three years			263,000
Gross Unrealized Losses, Due within one year	167,000
Gross Unrealized Losses, Due in one to two years	456,000		102,000
Gross Unrealized Losses, Due in two to three years	405,000		128,000
Fair Value, Due in one to two years	50,101,000		50,837,000
Fair Value, Due in two to three years	49,599,000		45,718,000
U.S. corporate debt security
Available-for-sale securities
Amortized Cost, Due in two to three years	10,046,000		9,406,000
Gross Unrealized Losses, Due in two to three years	22,000		77,000
Fair Value, Due in two to three years	$ 10,024,000		$ 9,329,000