Note 6 - Earnings (Loss) Per Share - Potentially Dilutive Securities Excluded from Diluted Net Income (Loss) per Share (Details) - shares shares in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Total antidilutive shares (in shares)	4,600	4,608	4,609	4,613
Share-based Payment Arrangement, Option [Member]
Total antidilutive shares (in shares)	4	11	8	13
Restricted Stock Units (RSUs) [Member]
Total antidilutive shares (in shares)	9	10	14	13
Convertible Debt Securities [Member]
Total antidilutive shares (in shares)	4,587	4,587	4,587	4,587

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=124432515&loc=d3e3550-109257

Name:	us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration