Note 6 - Property, Plant and Equipment (Tables)

6 Months Ended

Jun. 30, 2018

Notes Tables

Property, Plant and Equipment [Table Text Block]

	Useful Life		June 30,			December 31,
	(in years)		2018			2017
Construction in progress			$	537		$	479
Plant machinery and equipment		10		16,285			16,284
Site improvements		10		7,055			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		1,808			1,795
Leasehold improvements, pilot plant, land and support equipment		2-5		2,536			2,536
Total property, plant and equipment				111,716			111,640
Less accumulated depreciation and amortization				(44,536	)		(41,271	)
Property, plant and equipment, net			$	67,180		$	70,369