Revenue from Contracts with Customers - Revenue Disaggregation (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jul. 31, 2018	Jul. 31, 2018
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ 6,012	$ 9,720
Revenue recognized at a point in time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	5,809	9,310
Revenue recognized over time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	203	410
Seamap | Revenue recognized at a point in time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	3,611	5,156
Seamap | Revenue recognized over time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	203	410
Klein | Revenue recognized at a point in time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	1,401	2,877
SAP | Revenue recognized at a point in time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ 797	$ 1,277