Property, Plant and Equipment (Details Textual) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Property, Plant and Equipment [Line Items]
Depreciation expense			$ 1,133	$ 822
Interest costs capitalized			477	0
Construction in progress
Property, Plant and Equipment [Line Items]
Interest costs capitalized	$ 1,500	$ 700	2,800	1,200
Payroll costs	$ 700	$ 200	$ 1,100	$ 400