CASH, CASH EQUIVALENTS AND SHORT-TERM INVESTMENTS (Details) - Held-to-maturity Securities - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jul. 31, 2020	Jan. 31, 2020
Cash and Cash Equivalents
Maturity period	194 days	165 days
Accrued interest on held-to-maturity securities	$ 0.2	$ 0.5
Weighted average annual interest rates of CDs (as a percent)	1.60%	1.80%