CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2019	Oct. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 2,211	$ (598)	$ 9,966	$ 1,887
Other comprehensive income:
Unrealized gain on available-for-sale marketable securities, net of tax	719	85	786	142
Comprehensive income (loss)	$ 2,930	$ (513)	$ 10,752	$ 2,029