Significant Accounting Policies - Summary of Amounts Recorded in the Accompanying Balance Sheets as Receivables from the Granting Agencies (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Basis Of Presentation And Significant Accounting Policies [Line Items]
Unbilled grant receivable	$ 2,906	$ 1,300
Alzheimer's Association Part the Cloud Research Grant
Basis Of Presentation And Significant Accounting Policies [Line Items]
Unbilled grant receivable		224
National Institutes of Health Grant
Basis Of Presentation And Significant Accounting Policies [Line Items]
Unbilled grant receivable	$ 2,906	$ 1,076