Business segment reporting (Details) $ in Thousands	3 Months Ended	9 Months Ended
Oct. 31, 2017 USD ($) Segments	Oct. 31, 2016 USD ($)	Oct. 31, 2017 USD ($)	Oct. 31, 2016 USD ($)
Segment reporting
Number of reportable segments \| Segments	1
Net sales	$ 27,498	$ 25,302	$ 77,851	$ 71,230
Gross profit	3,320	3,697	8,163	8,669
Loss from operations	(2,291)	(1,175)	$ (8,213)	(7,965)
Piping Systems [Member]
Segment reporting
Segment reporting information, description of Products and Services			Piping Systems engineers, designs, manufactures and sells specialty piping, leak detection and location systems
Net sales	27,498	25,302	$ 77,851	71,230
Gross profit	3,320	3,697	8,163	8,669
Loss from operations	(428)	640	(1,825)	(1,775)
Corporate Segment [Member]
Segment reporting
Loss from operations	$ (1,863)	$ (1,815)	$ (6,388)	$ (6,190)

Description of the types of products and services from which the reportable segment derives its revenue.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 21
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=68060357&loc=d3e8721-108599

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Aggregate revenue less cost of goods and services sold or operating expenses directly attributable to the revenue generation activity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1,2)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

+ References

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The net result for the period of deducting operating expenses from operating revenues.

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Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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