Basis of Presentation - Supplementary cash flows information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Non-cash information:
Right-of-use asset and lease liability recognized	$ 3,140	$ 2,338
Additions to property, plant and equipment included in accounts payable	340	46
Warrants exercised for common stock	0	104
Interest paid (net of interest capitalized)	$ 5	$ 6