Note 5 - Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2018

Notes Tables

Property, Plant and Equipment [Table Text Block]

					December 31,
	(in years)				201 8			201 7
Construction in progress			–		$	3,478		$	479
Plant machinery and equipment			10			16,285			16,284
Site improvements			10			7,055			7,051
Agri-Energy Retrofit asset			20			70,842			70,842
Lab equipment, furniture and fixtures and vehicles			5			6,574			6,513
Demonstration plant			2			3,597			3,597
Buildings			10			2,543			2,543
Computer, office equipment and software			3			1,848			1,795
Leasehold improvements, pilot plant, land and support equipment		2	—	5		2,542			2,536
Total property, plant and equipment						114,764			111,640
Less accumulated depreciation and amortization						(47,728	)		(41,271	)
Property, plant and equipment, net					$	67,036		$	70,369