Product warranty - Schedule of Product Warranty Reserve (Details) - USD ($) |
12 Months Ended | |
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Dec. 31, 2018 |
Dec. 31, 2017 |
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| Guarantees [Abstract] | ||
| Product warranty period | 1 year | |
| Schedule of Product Warranty Reserve [Roll Forward] | ||
| Warranty reserve, beginning balance | $ 133,500 | $ 148,000 |
| Warranty provision for units sold | 348,100 | 128,100 |
| Costs of warranty incurred | (341,000) | (142,600) |
| Warranty reserve, ending balance | $ 140,600 | $ 133,500 |
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- Definition Product Warranty Period No definition available.
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- References No definition available.
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- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available.
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- Definition Amount as of the balance sheet date of the aggregate standard product warranty liability. Does not include the balance for the extended product warranty liability. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of decrease in the standard product warranty accrual from payments made in cash or in kind to satisfy claims under the terms of the standard product warranty. Excludes extended product warranties. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of increase in the standard product warranty accrual from warranties issued. Excludes extended product warranties. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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