Business segment reporting (Details) $ in Thousands	3 Months Ended	12 Months Ended
Apr. 30, 2016 USD ($) Segments	Apr. 30, 2015 USD ($)	Jan. 31, 2016
Segment reporting
Number of reportable segments \| Segments	1
Net sales	$ 23,069	$ 20,277
Gross profit	1,992	2,355
Loss from operations	$ (4,505)	(3,570)
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	$ 23,069	20,277
Gross profit	1,992	2,355
Loss from operations	(1,701)	(1,426)
Corporate Segment [Member]
Segment reporting
Loss from operations	$ (2,804)	$ (2,144)
Credit Concentration Risk [Member]
Segment reporting
Concentration Risk, Percentage	28.00%		46.00%
Sales Revenue, Net [Member]
Segment reporting
Concentration Risk, Percentage	15.00%	11.00%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=51801978&loc=d3e6351-108592

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=49121117&loc=d3e13531-108611

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=51801978&loc=d3e6404-108592

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
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-Section 50
-Paragraph 21
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Description of the types of products and services from which the reportable segment derives its revenue.

+ References

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=51669610&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)
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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.

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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.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
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-Paragraph 2
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