Note 8 - Fair Value of Financial Instruments - Assets and Liabilities Measured on Recurring Basis (Details) - Fair Value, Recurring [Member] - Money Market Funds [Member] - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Money market account	$ 51,797	$ 51,796
Fair Value, Inputs, Level 1 [Member]
Money market account	51,797	51,796
Fair Value, Inputs, Level 2 [Member]
Money market account	0	0
Fair Value, Inputs, Level 3 [Member]
Money market account	$ 0	$ 0

Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

No definition available.

Name:	us-gaap_CashAndCashEquivalentsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant