Note 7 - Income Taxes - Deferred Tax Assets for Loss and Tax Credit Carryforwards (Details) $ in Millions	Dec. 31, 2022 USD ($)
Net operating losses	$ 278
Tax credits	3
Balance as of December 31, 2022	281
Tax Years 2023 Through 2027 [Member]
Net operating losses	94
Balance as of December 31, 2022	94
Tax Years 2028 Through 2032 [Member]
Net operating losses	27
Tax credits	3
Balance as of December 31, 2022	30
Tax Years 2033 Through 2042 [Member]
Net operating losses	24
Balance as of December 31, 2022	24
Indefinite [Member]
Net operating losses	133
Balance as of December 31, 2022	$ 133

Amount, before allocation of a valuation allowances, of deferred tax assets attributable to deductible tax credit carryforwards including, but not limited to, research, foreign, general business, alternative minimum tax, and other deductible tax credit carryforwards.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 8
-URI https://asc.fasb.org/extlink&oid=121826272&loc=d3e32632-109319

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=121826272&loc=d3e32559-109319

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 6
-URI https://asc.fasb.org/extlink&oid=121826272&loc=d3e32621-109319

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