Note 6 - Property and Equipment (Details Textual) - USD ($) $ in Thousands	1 Months Ended			3 Months Ended		12 Months Ended
	Dec. 31, 2018	Aug. 31, 2018	Oct. 30, 2016	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Capital Leases, Lessee Balance Sheet, Assets by Major Class, Accumulated Depreciation	$ 900			$ 900		$ 900	$ 500
Property, Plant and Equipment, Net, Ending Balance	103,447			103,447		103,447	78,756
Proceeds from Sale of Property, Plant, and Equipment, Total						141	146	$ 33
Gain (Loss) on Disposition of Property Plant Equipment, Total						(222)	51	$ (19)
Monterrey, Mexico Facility [Member]
Proceeds from Sale of Property, Plant, and Equipment, Total	2,700
Gain (Loss) on Disposition of Property Plant Equipment, Total	200			200
Property in Houston, Texas [Member]
Proceeds from Sale of Property, Plant, and Equipment, Total		$ 5,800
Gain (Loss) on Disposition of Property Plant Equipment, Total		$ 2,800			$ 2,800
Denver Facility [Member]
Proceeds from Sale of Property, Plant, and Equipment, Total			$ 13,900
Gain (Loss) on Disposition of Property Plant Equipment, Total			$ 7,900
MEXICO
Property, Plant and Equipment, Net, Ending Balance	$ 21,600			$ 21,600		$ 21,600	$ 3,800