Note 2 - Revenue (Details Textual) - USD ($)	3 Months Ended
Mar. 31, 2023	Dec. 31, 2022
Contract with Customer, Liability, Revenue Recognized	$ 12
Deferred Revenue [Member]
Deposit Liability, Current	$ 14,000,000	$ 12,000,000

Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 8
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-8

Name:	us-gaap_ContractWithCustomerLiabilityRevenueRecognized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration