Note 9 - Debt - Long-term Debt (Details) (Parentheticals) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Issuance costs	$ 25
Mortgage Agreement [Member]
Interest rate	10.30%	10.30%
Interest rate, variable	7.00%	7.00%
Issuance costs	$ 25	$ 25
Original principal	$ 2,500	$ 2,500
Maturity date	Dec. 31, 2023	Dec. 31, 2023
Interest rate, effective rate	11.50%	11.50%
Original principal	$ 2,500	$ 2,500
Equipment Notes, May 2021 [Member] | Notes Payable, Other Payables [Member]
Original principal	$ 46
Maturity date	Jun. 30, 2025
Interest rate, effective rate	3.60%
Original principal	$ 46
Equipment Notes, December 2019 [Member] | Notes Payable, Other Payables [Member]
Original principal	$ 40
Maturity date	Dec. 31, 2024	Dec. 31, 2024
Interest rate, effective rate	9.30%	9.30%
Original principal	$ 40
Equipment Notes, November 2018 [Member] | Notes Payable, Other Payables [Member]
Interest rate	4.80%	4.80%
Maturity date	Aug. 31, 2022	Aug. 31, 2022