Supplemental Statements of Cash Flows Information - Supplemental Disclosures of Cash Flows Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Supplemental Cash Flow Elements [Abstract]
Interest paid	$ 63	$ 8	$ 86
Income taxes paid, net	498	622	494
Seismic equipment purchases included in accounts payable at year-end	$ 812	$ 0	$ 53