Note 5 - Supplemental Balance Sheet Information (Details Textual) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Restricted Cash and Cash Equivalents, Total	$ 87	$ 270
Grant [Member]
Revenues, Total	188
NETHERLANDS
Restricted Cash and Cash Equivalents, Total	$ 87	82
CHINA
Restricted Cash and Cash Equivalents, Total		$ 188