Note 2 - Variable Interest Entities - Consolidated VIEs' Financial Performance (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenues	$ 15,453		$ 22,520		$ 24,020	$ 30,780
Cost of revenues	(15,087)		(21,552)		(23,212)	(29,211)
Total operating expenses	1,588		9,288		2,768	11,434
Net loss before allocation to noncontrolling interests	(382)	$ (1,140)	(9,554)	$ (570)	(1,522)	(10,124)
VIEs [Member]
Revenues	15,453		22,520		24,020	30,773
Cost of revenues	(15,087)		(21,552)		(23,212)	(29,211)
Total operating expenses	(1,151)		(8,763)		(1,862)	(10,025)
Net loss before allocation to noncontrolling interests	$ (764)		$ (8,183)		$ (1,086)	$ (8,861)