Common Stock - Summary of Share-Based Compensation Expense (Detail) - USD ($) $ in Thousands |
12 Months Ended | ||
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Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
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| Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] | |||
| Total stock-based compensation | $ 1,286 | $ 1,201 | $ 854 |
| Research and development [Member] | |||
| Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] | |||
| Total stock-based compensation | 403 | 364 | |
| General and administrative [Member] | |||
| Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] | |||
| Total stock-based compensation | $ 883 | $ 837 | |
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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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- Definition Amount of noncash expense for share-based payment arrangement. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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