Note 2 - Variable Interest Entities - Consolidated VIEs' Financial Performance (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenues	$ 22,520	$ 10,500	$ 30,780	$ 17,764
Cost of revenues	(21,552)	(8,800)	(29,211)	(14,792)
Total operating expenses	(9,288)	(2,122)	(11,434)	(4,443)
Net loss	(9,554)	(757)	(10,124)	(1,826)
VIEs [Member]
Revenues	22,520	10,469	30,773	17,733
Cost of revenues	(21,552)	(8,800)	(29,211)	(14,792)
Total operating expenses	(8,763)	(1,526)	(10,025)	(3,159)
Net loss	$ (8,183)	$ (163)	$ (8,861)	$ (516)