STOCK-BASED COMPENSATION - Summary of Change in Number of Non-Vested Options to Purchase Shares of Common Stock (Details) - $ / shares shares in Thousands	3 Months Ended
	Apr. 30, 2018	Apr. 30, 2017
STOCK-BASED COMPENSATION
Shares, Non-vested, Beginning balance	302	270
Shares, Granted	97	105
Shares, Vested	(105)	(75)
Shares, Non-vested, Ending balance	294	300
Weighted Average Fair Value, Non-vested, Beginning balance	$ 13.55	$ 14.93
Weighted Average Fair Value, Granted	8.74	16.37
Weighted Average Fair Value, Vested	16.37	9.01
Weighted Average Fair Value, Non-vested, Ending balance	$ 10.95	$ 17.38