| Inventories - Summary of Inventories (Detail) - USD ($) $ in Thousands | Dec. 31, 2020 | Dec. 31, 2019 | 
|---|---|---|
| Inventory, Net [Abstract] | ||
| Raw materials | $ 1,657 | $ 919 | 
| Finished goods including machinery | 507 | 422 | 
| Total | $ 2,164 | $ 1,341 | 
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- Definition Amount before valuation and LIFO reserves of completed merchandise or goods expected to be sold within one year or operating cycle, if longer. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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| X | ||||||||||
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- Definition Amount after valuation and LIFO reserves of inventory expected to be sold, or consumed within one year or operating cycle, if longer. 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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| X | ||||||||||
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- Definition Amount before valuation and LIFO reserves of raw materials expected to be sold, or consumed within one year or operating cycle, if longer. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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