Note 14 - Stock-based Compensation - Stock Options Outstanding (Details)	12 Months Ended
Dec. 31, 2020 $ / shares shares
Options, Exercisable, Number of Shares (in shares) \| shares	1,282,678
Options, Exercisable, Weighted Average Exercise Price (in dollars per share) \| $ / shares	$ 27.71
Options, Exercisable, Weighted Average Remaining Contractual Term (Year)	4 years 9 months 21 days
Options, Vested and Expected to Vest, Exercisable, Number of Shares (in shares) \| shares	4,141,694
Options, Vested and Expected to Vest, Exercisable, Weighted Average Exercise Price (in dollars per share) \| $ / shares	$ 10.89
Options, Vested and Expected to Vest, Exercisable, Weighted Average Remaining Contractual Term (Year)	6 years 18 days

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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Number of fully vested and expected to vest exercisable options that may be converted into shares under option plan. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Weighted-average exercise price, at which grantee can acquire shares reserved for issuance, for fully vested and expected to vest exercisable or convertible options. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Weighted average remaining contractual term for fully vested and expected to vest exercisable or convertible options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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