Note 2 - Summary of Significant Accounting Policies (Details Textual) € in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2023 EUR (€)	Dec. 31, 2022 USD ($)	Mar. 31, 2022 USD ($)	May 31, 2018 USD ($)
Restricted Cash	$ 0		$ 0			$ 1,142
Accounts Receivable, Allowance for Credit Loss, Recovery			79
Accounts Receivable, Credit Loss Expense (Reversal)			0
Inventory Write-down	131	$ 107	266	$ 230
Deferred Grant Proceeds	273		273
City of Rochester and State of New York [Member]
Contingent Liability, Repayment of State and Local Grant Funds Received							$ 87	$ 550
Covenant, Future Amount Receivable	193		193
Bank Guarantee on Customer Order Deposit [Member]
Restricted Cash	$ 1,142		$ 1,142		€ 1,067