Note 6 - Long-term Debt - Carrying Amount of the Company's Outstanding Debt (Details) (Parentheticals)	Dec. 31, 2020	Dec. 31, 2019
Senior Secured Debt, Due March 25, 2021 [Member]
Debt instrument, interest rate, stated percentage	8.00%	8.00%
Convertible Senior Notes Due March 5, 2020 [Member]
Debt instrument, interest rate, stated percentage	7.00%	7.00%

Contractual interest rate for funds borrowed, under the debt agreement.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant