Note 13 - Stock-based Compensation - Stock Based Compensation Expense (Details) - USD ($) $ in Thousands  | 
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2023  | 
Jun. 30, 2022  | 
Jun. 30, 2023  | 
Jun. 30, 2022  | 
|
| Stock based compensation | $ 514 | $ 582 | $ 938 | $ 1,081 | 
| Selling and Marketing Expense [Member] | ||||
| Stock based compensation | 76 | 72 | 140 | 141 | 
| Research and Development Expense [Member] | ||||
| Stock based compensation | 131 | 104 | 213 | 183 | 
| General and Administrative Expense [Member] | ||||
| Stock based compensation | $ 307 | $ 406 | $ 585 | $ 757 | 
| X | ||||||||||
- Definition Amount of expense for award under share-based payment arrangement. Excludes amount capitalized. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
  | 
| X | ||||||||||
- Details 
  | 
| X | ||||||||||
- Details 
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| X | ||||||||||
- Details 
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