Property, Plant and Equipment (Details Textual) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 600	$ 400	$ 1,703	$ 1,264
Interest costs capitalized			2,013	1,058
Construction in progress
Property, Plant and Equipment [Line Items]
Interest costs capitalized	1,500	1,100	4,400	2,300
Payroll costs	$ 400	$ 200	$ 1,500	$ 600