Note 2 - Summary of Significant Accounting Policies (Details Textual) € in Thousands, $ in Thousands	9 Months Ended
	Sep. 30, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2022 EUR (€)	Mar. 31, 2022 USD ($)	May 31, 2018 USD ($)
Restricted Cash	$ 0	$ 1,142
Accounts Receivable, Allowance for Credit Loss, Recovery	79
Accounts Receivable, Credit Loss Expense (Reversal)	0
Deferred Grant Proceeds	259
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
Bank Guarantee on Customer Order Deposit [Member]
Restricted Cash		$ 1,142	€ 1,067