Note 7 - Property, Plant and Equipment (Details Textual) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Depreciation, Total	$ 2,500		$ 2,800	$ 7,500	$ 8,900
Proceeds from Sale of Property, Plant, and Equipment, Total				5,787	53
Gain (Loss) on Disposition of Property Plant Equipment, Total				4,257
Inwood, New York Property [Member]
Proceeds from Sale of Property, Plant, and Equipment, Total		$ 5,800
Gain (Loss) on Disposition of Property Plant Equipment, Total	$ 4,300			$ 4,300