Note 5 - Other Assets - Schedule of Other Assets, Net (Parenthetical) (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Other Assets Unclassified [Abstract]
Other receivables, net of allowance	$ 78	$ 82

Amount of allowance for credit loss on receivable, classified as other and current.

No definition available.

Name:	us-gaap_AllowanceForDoubtfulOtherReceivablesCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant