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Discontinued Operations (Details) - USD ($)	3 Months Ended		9 Months Ended
Discontinued Operations (Details) - USD ($)	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets held for sale					$ 485,000
Storage costs	$ 1,000		$ 135,000
Fuel Conversion Segment
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Severance costs	5,000		65,000
Research and Development, severance and other costs		$ 10,000		$ 109,000
Revenue			0
Fuel Conversion Segment \| Accrued Liabilities
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Accrued severance charges	0		0		65,000
Sold \| Fuel Conversion Segment
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal consideration					505,000
Gain on sale			20,000
Storage costs	2,000		21,000
Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets held for sale	$ 0		$ 0		$ 485,000