Note 7 - Income Taxes (Details Textual) - USD ($) $ in Millions	3 Months Ended
Jun. 30, 2020	Jun. 30, 2022	Dec. 31, 2021
Deferred Tax Assets, Net, Total		$ 258.6	$ 202.8
Deferred Tax Assets, Valuation Allowance, Total		260.9	$ 204.9
Income Tax Benefit, Cares Act	$ 6.9
SPO [Member]
Deferred Tax Assets, Net, Total		55.0
Deferred Tax Assets, Valuation Allowance, Total		$ 55.0

Amount, after allocation of valuation allowances and deferred tax liability, of deferred tax asset attributable to deductible differences and carryforwards, without jurisdictional netting.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 2
-URI https://asc.fasb.org/extlink&oid=121826272&loc=d3e32537-109319

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant