Stock Plans - Stock-based compensation expense (Details) - USD ($) $ in Thousands |
3 Months Ended | |
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Mar. 31, 2022 |
Mar. 31, 2021 |
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| Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost | ||
| Total stock-based compensation expenses | $ 226 | $ 248 |
| Research and development | ||
| Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost | ||
| Total stock-based compensation expenses | 123 | 120 |
| General and administrative | ||
| Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost | ||
| Total stock-based compensation expenses | $ 103 | $ 128 |
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- Definition Amount of expense for award under share-based payment arrangement. Excludes amount capitalized. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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