Note 5 - Supplemental Balance Sheet Information (Details Textual) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Restricted Cash and Cash Equivalents, Total	$ 82		$ 84
Depreciation, Total	816	$ 730
Amortization of Intangible Assets	328	154
Selling, General and Administrative Expenses [Member]
Amortization of Intangible Assets	302	121
Research and Development Expense [Member]
Amortization of Intangible Assets	26	$ 33
NETHERLANDS
Restricted Cash and Cash Equivalents, Total	$ 82		$ 84