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Revenue Recognition - Revenue Disaggregated by Product Line and Geographic Area (Detail) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended
--- | --- | ---
Sep. 30, 2019 | Sep. 30, 2018 | Sep. 30, 2019 | Sep. 30, 2018
Disaggregation Of Revenue [Line Items] |  |  |  |
Net sales | $ 21,643 | $ 21,441 | $ 42,236 | $ 50,992
Heat Transfer Equipment [Member] |  |  |  |
Disaggregation Of Revenue [Line Items] |  |  |  |
Net sales | 6,479 | 6,173 | 14,331 | 10,331
Vacuum Equipment [Member] |  |  |  |
Disaggregation Of Revenue [Line Items] |  |  |  |
Net sales | 8,733 | 7,842 | 14,263 | 25,058
All Other [Member] |  |  |  |
Disaggregation Of Revenue [Line Items] |  |  |  |
Net sales | 6,431 | 7,426 | 13,642 | 15,603
Asia [Member] |  |  |  |
Disaggregation Of Revenue [Line Items] |  |  |  |
Net sales | 1,018 | 1,876 | 4,237 | 4,625
Canada [Member] |  |  |  |
Disaggregation Of Revenue [Line Items] |  |  |  |
Net sales | 1,896 | 3,473 | 3,244 | 15,123
Middle East [Member] |  |  |  |
Disaggregation Of Revenue [Line Items] |  |  |  |
Net sales | 512 | 464 | 1,285 | 899
South America [Member] |  |  |  |
Disaggregation Of Revenue [Line Items] |  |  |  |
Net sales | 2,117 | 68 | 2,476 | 192
U.S. [Member] |  |  |  |
Disaggregation Of Revenue [Line Items] |  |  |  |
Net sales | 15,731 | 15,073 | 30,179 | 28,526
All Other [Member] |  |  |  |
Disaggregation Of Revenue [Line Items] |  |  |  |
Net sales | $ 369 | $ 487 | $ 815 | $ 1,627

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- Definition 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. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 606 -SubTopic 10 -Section 50 -Paragraph 4 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130543-203045 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 606 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130545-203045 + Details
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