Note 11 - Convertible Senior Notes - Summary of Convertible Senior Notes (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Net carrying value	$ 0	$ 24,386
Five Point Eight Seven Five Percent Convertible Senior Notes Due Two Thousand Thirty Five [Member] \| Convertible Debt [Member]
Face amount of convertible senior notes	33,839
Discount	(9,453)
Net carrying value	24,386
Carrying amount of equity component included in paid-in capital	108,714
Excess of instruments’ if-converted values over face principal amounts	$ 0

Including the current and noncurrent portions, carrying amount of debt identified as being convertible into another form of financial instrument (typically the entity's common stock) as of the balance sheet date, which originally required full repayment more than twelve months after issuance or greater than the normal operating cycle of the company.

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The carrying amount of the equity component of convertible debt which may be settled in cash upon conversion.

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The amount by which the convertible debt's if-converted value exceeds its principle amount at the balance sheet date, regardless of whether the instrument is currently convertible. This element applies to public companies only.

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