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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, 2020 | Sep. 30, 2019 | Sep. 30, 2020 | Sep. 30, 2019
Disaggregation Of Revenue [Line Items] |  |  |  |
Net sales | $ 27,954 | $ 21,643 | $ 44,664 | $ 42,236
Heat Transfer Equipment [Member] |  |  |  |
Disaggregation Of Revenue [Line Items] |  |  |  |
Net sales | 13,307 | 6,479 | 23,980 | 14,331
Vacuum Equipment [Member] |  |  |  |
Disaggregation Of Revenue [Line Items] |  |  |  |
Net sales | 9,381 | 8,733 | 11,932 | 14,263
All Other [Member] |  |  |  |
Disaggregation Of Revenue [Line Items] |  |  |  |
Net sales | 5,266 | 6,431 | 8,752 | 13,642
Asia [Member] |  |  |  |
Disaggregation Of Revenue [Line Items] |  |  |  |
Net sales | 4,529 | 1,018 | 9,692 | 4,237
Canada [Member] |  |  |  |
Disaggregation Of Revenue [Line Items] |  |  |  |
Net sales | 1,938 | 1,896 | 2,930 | 3,244
Middle East [Member] |  |  |  |
Disaggregation Of Revenue [Line Items] |  |  |  |
Net sales | 988 | 512 | 1,437 | 1,285
South America [Member] |  |  |  |
Disaggregation Of Revenue [Line Items] |  |  |  |
Net sales | 2,592 | 2,117 | 2,812 | 2,476
U.S. [Member] |  |  |  |
Disaggregation Of Revenue [Line Items] |  |  |  |
Net sales | 17,252 | 15,731 | 26,690 | 30,179
All Other [Member] |  |  |  |
Disaggregation Of Revenue [Line Items] |  |  |  |
Net sales | $ 655 | $ 369 | $ 1,103 | $ 815

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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 280 -SubTopic 10 -Section 50 -Paragraph 30 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8906-108599 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 40 -URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e9031-108599 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 41 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e9038-108599 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 32 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8933-108599 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 32 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8933-108599 Reference 6: 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=121604090&loc=SL49130543-203045 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 22 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8736-108599 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 22 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8736-108599 Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 42 -URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e9054-108599 Reference 10: 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=121604090&loc=SL49130545-203045 Reference 11: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 924 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 11.L) -URI http://asc.fasb.org/extlink&oid=6472922&loc=d3e499488-122856 + Details
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