Quarterly report pursuant to Section 13 or 15(d)

Organization and Principal Activities - Additional Information (Details)

v3.21.2
Organization and Principal Activities - Additional Information (Details)
$ in Thousands
9 Months Ended
Sep. 30, 2021
USD ($)
Segment
Dec. 31, 2020
USD ($)
Organization Consolidation And Presentation Of Financial Statements [Line Items]    
Date of incorporation Apr. 21, 2003  
Headquartered in South San Francisco  
Headquartered in state CA  
Number of operating segments | Segment 1  
Accumulated deficit $ 295,286 $ 227,873
Unrestricted cash, cash equivalents and marketable securities $ 254,200  
Substantial doubt about going concern, within one year false  
Minimum    
Organization Consolidation And Presentation Of Financial Statements [Line Items]    
Period from issuance date of unaudited interim condensed financial statements 12 months