Commitments and contingencies	3 Months Ended
Commitments and contingencies	Mar. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and contingencies	Commitments and Contingencies The Company guarantees certain obligations of a former subsidiary of American DG Energy, EuroSite Power Inc. These guarantees include a payment performance guarantee in respect of collateralized equipment financing loans, with a remaining principal amount outstanding subject to the guarantee at March 31, 2019 of approximately $190,000 due ratably in equal installments through September 2021, and certain guarantees of performance in respect of certain customer contracts. Based on current conditions, the Company does not believe there to be any amounts probable of payment by the Company under any of the guarantees and has estimated the value associated with the non-contingent aspect of the guarantees is approximately $7,000 which is recorded as a liability in the accompanying financial statements. In connection with the sale of energy producing assets, the Company made certain guarantees to the purchaser as discussed in Note 6. Sale of Energy Producing Assets and Goodwill Impairment. The Company has recorded a reduction on the gain on sale and a corresponding liability of $350,000 in the accompanying financial statements to reserve for such future costs.