Revenue from Contracts with Customers - Revenue Disaggregation (Detail) - USD ($) $ in Thousands	3 Months Ended
Apr. 30, 2019	Apr. 30, 2018
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ 5,982	$ 3,708
Revenue recognized at a point in time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	5,776	3,502
Revenue recognized over time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	206	206
Seamap \| Revenue recognized at a point in time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	4,118	1,510
Seamap \| Revenue recognized over time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	206	206
Klein \| Revenue recognized at a point in time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	1,557	1,512
SAP \| Revenue recognized at a point in time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ 101	$ 480

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130543-203045

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130539-203045

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130545-203045

Name:	us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration