Note 13 - Stockholders' Equity - Reserved Shares (Details) - shares |
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
|---|---|---|---|
| Subject to outstanding options and restricted shares (in shares) | 7,011,839 | ||
| Available for future grants (in shares) | 3,398,870 | 2,402,326 | 805,749 |
| Officer and Director Purchase Plan (in shares) | 237,382 | ||
| Shares subject to purchase (in shares) | 103,500 | ||
| Common Stock, Capital Shares Reserved for Future Issuance | 10,751,591 |
| X | ||||||||||
- Definition Number of shares reserved for future issuance under Officer and Director Purchase Plan. No definition available.
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| X | ||||||||||
- Definition Number of shares reserved for future issuance subject to outstanding options and restricted shares under share-based payment arrangement. No definition available.
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| X | ||||||||||
- Definition Number of warrants or rights outstanding. No definition available.
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| X | ||||||||||
- Definition Aggregate number of common shares reserved for future issuance. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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