| Share-Based Compensation - Summary of Share-based Compensation Expense (Details) - USD ($) $ in Thousands | 12 Months Ended | ||
|---|---|---|---|
| Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018 | |
| Research and Development Expense | |||
| Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] | |||
| Share-based compensation expense | $ 754 | $ 723 | $ 398 | 
| General and Administrative Expense | |||
| Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] | |||
| Share-based compensation expense | $ 2,005 | $ 1,450 | $ 892 | 
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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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