Note 8 - Stock-based Compensation - Restricted Stock Options (Details) - Restricted Stock [Member] - $ / shares |
3 Months Ended | |
|---|---|---|
Mar. 31, 2023 |
Mar. 31, 2022 |
|
| Restricted stock (in shares) | 478,596 | |
| Restricted stock, weighted-average grant date fair value (in dollars per share) | $ 70.36 | |
| Granted (in shares) | 88,658 | |
| Granted, weighted-average grant date fair value (in dollars per share) | 33.84 | |
| Restrictions lapsed (in shares) | (37,528) | |
| Restrictions lapsed, weighted-average grant date fair value (in dollars per share) | 111.56 | |
| Forfeited (in shares) | (23,807) | |
| Forfeited, weighted-average grant date fair value (in dollars per share) | 75.18 | |
| Restricted stock (in shares) | 505,919 | |
| Restricted stock, weighted-average grant date fair value (in dollars per share) | $ 60.57 | |
| X | ||||||||||
- Definition The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition Per share or unit weighted-average fair value of nonvested award under share-based payment arrangement. Excludes share and unit options. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Details
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