Annual report pursuant to Section 13 and 15(d)

Lease - Additional Information (Details)

v3.20.4
Lease - Additional Information (Details)
$ in Thousands
12 Months Ended
Dec. 31, 2020
USD ($)
ft²
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Operating lease existence of option to extend [true false] true    
Operating lease, option to extend The operating lease agreement has one option to extend the lease term for a period of five years at the fair market rate at the time of the extension.    
Operating lease, renewal term 5 years    
Weighted average remaining lease term 4 years 2 months 1 day    
Operating lease liability, weighted average discount rate 10.00%    
Rent expense $ 1,100 $ 1,100 $ 1,000
Variable lease costs $ 542 $ 505 $ 400
South San Francisco, California [Member]      
Area of lease | ft² 24,357    
Lease commenced date Mar. 01, 2018    
Lease expiration date Feb. 28, 2025