Note 3 - Summary of Significant Accounting Policies (Details Textual) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Contract with Customer, Performance Obligation Satisfied in Previous Period		$ 0	$ 0	$ 0	$ 0
Research and Development Expense, Total		89	$ 116	163	$ 330
Operating Lease, Right-of-Use Asset	[1]	2,107		2,107		$ 48
Operating Lease, Liability, Total		$ 2,166		$ 2,166

[1] All of the VIEs' assets can be used to settle obligations of their primary beneficiary. Liabilities recognized as a result of consolidating these VIEs do not represent additional claims on the Company's general assets (Note 2).