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Note 13 - Stock-based Compensation - Options Outstanding by Exercise Price Range (Details) - $ / shares | 3 Months Ended |  |
--- | --- | --- | ---
Mar. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022
Options outstanding (in shares) | 696,386 | 588,534 | 445,144
Options outstanding, weighted average exercise price (in dollars per share) | $ 72.93 |  |
Options outstanding, weighted average remaining contractual life (Year) | 3 years 8 months 12 days |  |
Exercise Price Range 1 [Member] |  |  |
Options outstanding (in shares) | 377,405 |  |
Options outstanding, exercise price, lower range (in dollars per share) | $ 53.94 |  |
Options outstanding, exercise price, upper range (in dollars per share) | 69.19 |  |
Options outstanding, weighted average exercise price (in dollars per share) | $ 58.92 |  |
Options outstanding, weighted average remaining contractual life (Year) | 3 years 6 months |  |
Exercise Price Range 2 [Member] |  |  |
Options outstanding (in shares) | 318,981 |  |
Options outstanding, exercise price, lower range (in dollars per share) | $ 71.64 |  |
Options outstanding, exercise price, upper range (in dollars per share) | 94.1 |  |
Options outstanding, weighted average exercise price (in dollars per share) | $ 89.51 |  |
Options outstanding, weighted average remaining contractual life (Year) | 4 years |  |

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- Definition Number of options outstanding, including both vested and non-vested options. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 718 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c)(1)(i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480429/718-10-50-2 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 718 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c)(1)(ii) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480429/718-10-50-2 + Details
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- Definition The floor of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (g) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480429/718-10-50-2 + Details
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- Definition The ceiling of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (g) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480429/718-10-50-2 + Details
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- Definition The weighted average price as of the balance sheet date at which grantees could acquire the underlying shares with respect to all outstanding stock options which are in the customized range of exercise prices. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 718 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c)(1)(ii) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480429/718-10-50-2 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 718 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c)(1)(i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480429/718-10-50-2 + Details
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- Definition Weighted average remaining contractual term of outstanding stock options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 718 -SubTopic 10 -Subparagraph (e)(1) -Name Accounting Standards Codification -Paragraph 2 -Section 50 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480429/718-10-50-2 + Details
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