| Property, Plant and Equipment - Additional Information (Detail) - USD ($) $ in Thousands | 12 Months Ended | ||
|---|---|---|---|
| Mar. 31, 2021 | Mar. 31, 2020 | Mar. 31, 2019 | |
| Property Plant And Equipment [Abstract] | |||
| Depreciation expense | $ 1,945 | $ 1,957 | $ 1,968 | 
| X | ||||||||||
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- Definition The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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| X | ||||||||||
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- References No definition available. 
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