Note 5 - Property, Plant and Equipment (Tables)

3 Months Ended

Mar. 31, 2018

Notes Tables

Property, Plant and Equipment [Table Text Block]

	Useful Life			March 31,			December 31,
	(in years)			2018			2017
Construction in progress				$	507		$	479
Plant machinery and equipment		10			16,285			16,284
Site improvements		10			7,051			7,051
Luverne retrofit asset		20			70,842			70,842
Lab equipment, furniture and fixtures and vehicles		5			6,513			6,513
Demonstration plant		2			3,597			3,597
Buildings		10			2,543			2,543
Computer, office equipment and software		3			1,807			1,795
Leasehold improvements, pilot plant, land and support equipment	2	-	5		2,536			2,536
Total property, plant and equipment					111,681			111,640
Less accumulated depreciation and amortization					(42,917	)		(41,271	)
Property, plant and equipment, net				$	68,764		$	70,369