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Balance Sheet Components - Schedule of Prepaid Expenses and Other Non-Current Assets (Details) - USD ($) $ in Thousands | Dec. 31, 2020 | Dec. 31, 2019
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Prepaid Expense And Other Assets Noncurrent [Abstract] |  |
Prepaid clinical and research expenses |  | $ 1,462
Deferred offering costs |  | 894
Deposits | $ 608 | 58
Total prepaid expenses and other non-current assets | $ 608 | $ 2,414

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- Definition Carrying value of amounts transferred to third parties for security purposes that are expected to be returned or applied towards payment after one year or beyond the operating cycle, if longer. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.17) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
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