STOCK-BASED COMPENSATION - Summary of Change in Number of Non-Vested Options to Purchase Shares of Common Stock (Details) - $ / shares shares in Thousands	6 Months Ended
	Jul. 31, 2018	Jul. 31, 2017
STOCK-BASED COMPENSATION
Shares, Non-vested, Beginning balance	302	270
Shares, Granted	97	125
Shares, Vested	(125)	(105)
Shares, Forfeitures		(10)
Shares, Non-vested, Ending balance	274	280
Weighted Average Fair Value, Non-vested, Beginning balance	$ 13.55	$ 14.93
Weighted Average Fair Value, Granted	8.74	16.19
Weighted Average Fair Value, Vested	16.19	9.66
Weighted Average Fair Value, Forfeitures		19.14
Weighted Average Fair Value, Non-vested, Ending balance	$ 10.64	$ 17.83