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Contingencies (Details) - USD ($)
3 Months Ended
Mar. 31, 2020
Mar. 31, 2019
Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]      
Non-conformance accrual $ 146,000   $ 146,000
Change in warranty liability balance 0 $ 0  
Warranty liability balance $ 159,000 $ 159,000