Balance Sheet Components - Components of Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Balance Sheet Related Disclosures [Abstract]
Accrued legal and professional fees	$ 69	$ 86
Accrued manufacturing and clinical expenses	513	237
Accrued compensation	767	646
Other	61	50
Total Accrued Liabilities	$ 1,410	$ 1,019

Amount of expenses incurred but not yet paid classified as other, due within one year or the normal operating cycle, if longer.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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Balance Type:	credit
Period Type:	instant