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Revenue Recognition - Revenue Disaggregated by Product Line and Geographic Area (Detail) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2018 | Dec. 31, 2017
Disaggregation Of Revenue [Line Items] |  |  |  |
Net sales | $ 17,198 | $ 17,281 | $ 68,190 | $ 55,356
Heat Transfer Equipment [Member] |  |  |  |
Disaggregation Of Revenue [Line Items] |  |  |  |
Net sales | 5,164 | 7,608 | 15,495 | 18,591
Vacuum Equipment [Member] |  |  |  |
Disaggregation Of Revenue [Line Items] |  |  |  |
Net sales | 3,765 | 3,858 | 28,823 | 15,270
All Other [Member] |  |  |  |
Disaggregation Of Revenue [Line Items] |  |  |  |
Net sales | 8,269 | 5,815 | 23,872 | 21,495
Asia [Member] |  |  |  |
Disaggregation Of Revenue [Line Items] |  |  |  |
Net sales | 966 | 2,264 | 5,591 | 8,228
Canada [Member] |  |  |  |
Disaggregation Of Revenue [Line Items] |  |  |  |
Net sales | 549 | 1,847 | 15,672 | 5,046
Middle East [Member] |  |  |  |
Disaggregation Of Revenue [Line Items] |  |  |  |
Net sales | 806 | 1,023 | 1,705 | 2,958
South America [Member] |  |  |  |
Disaggregation Of Revenue [Line Items] |  |  |  |
Net sales | 47 | 485 | 239 | 1,055
U.S. [Member] |  |  |  |
Disaggregation Of Revenue [Line Items] |  |  |  |
Net sales | 14,320 | 11,301 | 42,846 | 37,276
All Other [Member] |  |  |  |
Disaggregation Of Revenue [Line Items] |  |  |  |
Net sales | $ 510 | $ 361 | $ 2,137 | $ 793

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