Quarterly report pursuant to Section 13 or 15(d)

Intangible Assets and Liabilities Other Than Goodwill -Amounts related to intangible assets (Details)

Intangible Assets and Liabilities Other Than Goodwill -Amounts related to intangible assets (Details) - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Intangible assets	$ 2,490,621	$ 3,754,762
Less - accumulated amortization	(935,987)	(860,772)
Intangible assets, net	1,554,634	2,893,990
Unfavorable contract liability	4,689,025	7,912,275
Less - accumulated amortization	(1,934,528)	(1,619,676)
Unfavorable contract liability, net	2,754,497	6,292,599
Product Certifications
Finite-Lived Intangible Assets [Line Items]
Intangible assets	726,159	726,159
Less - accumulated amortization	(372,782)	(345,658)
Intangible assets, net	353,377	380,501
Patents
Finite-Lived Intangible Assets [Line Items]
Intangible assets	930,509	910,569
Less - accumulated amortization	(198,362)	(188,239)
Intangible assets, net	732,147	722,330
Developed Technology
Finite-Lived Intangible Assets [Line Items]
Intangible assets	240,000	240,000
Less - accumulated amortization	(100,000)	(92,000)
Intangible assets, net	140,000	148,000
Favorable contract asset
Finite-Lived Intangible Assets [Line Items]
Intangible assets	274,858	1,561,739
Less - accumulated amortization	(260,217)	(232,099)
Intangible assets, net	14,641	1,329,640
TTcogen Intangible Assets
Finite-Lived Intangible Assets [Line Items]
Intangible assets	29,607	0
Less - accumulated amortization	(4,626)	0
Intangible assets, net	24,981	0
Trademarks
Finite-Lived Intangible Assets [Line Items]
Intangible assets	25,552	22,752
Less - accumulated amortization	0	0
Intangible assets, net	25,552	22,752
In Process R&D
Finite-Lived Intangible Assets [Line Items]
Intangible assets	263,936	263,936
Less - accumulated amortization	0	0
Intangible assets, net	$ 263,936	$ 263,936