Note 5 - Supplemental Balance Sheet Information (Details Textual) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Ending Balance	$ 10,653	$ 7,405	$ 25,934
Restricted Cash and Cash Equivalents, Total	91	270
Revenues, Total	107,712	106,795
Depreciation, Total	$ 2,340	2,220
Number of Reporting Units	5
Goodwill, Impairment Loss	$ 0
Finite-Lived Intangible Asset, Expected Amortization, Year One	352
Finite-Lived Intangible Asset, Expected Amortization, Year Two	337
Finite-Lived Intangible Asset, Expected Amortization, Year Three	334
Finite-Lived Intangible Asset, Expected Amortization, Year Four	324
Finite-Lived Intangible Asset, Expected Amortization, Year Five	324
Grant [Member]
Revenues, Total	188
NETHERLANDS
Restricted Cash and Cash Equivalents, Total	$ 91	82
CHINA
Restricted Cash and Cash Equivalents, Total		$ 188