Note 10 - Income Taxes - Valuation Allowances (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Federal Income Tax, Valuation Allowances [Abstract]
Deferred Tax Assets, Valuation Allowance	$ 77,728	$ 66,437

Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32537-109319

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