Annual report pursuant to Section 13 and 15(d)

Equity Incentive Plans, Employee Stock Purchase Plan and Stock-Based Compensation - Additional Information (Details)

v3.20.4
Equity Incentive Plans, Employee Stock Purchase Plan and Stock-Based Compensation - Additional Information (Details) - USD ($)
1 Months Ended 12 Months Ended
Sep. 26, 2018
Sep. 25, 2018
Aug. 31, 2019
Feb. 28, 2017
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Jan. 01, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                
Reserved common stock         8,331,103 7,357,234    
Aggregate intrinsic value of stock options exercised         $ 1,200,000 $ 200,000 $ 200,000  
Expected dividend yield         0.00%      
Weighted-average estimated grant-date fair value of employee stock options granted         $ 5.59 $ 6.71 $ 9.48  
Share-based compensation arrangement by share-based payment award options, shares granted         266,724 266,724    
Stock-based compensation expense         $ 11,917,000 $ 10,312,000 $ 2,872,000  
Liability attributable to call option plan         $ 109,000 $ 76,000    
2018 Equity Incentive Plan                
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                
Reserved common stock   2,300,000            
Annual increase period of common stock reserved for issuance   10 years            
Maximum number of shares issuable               1,154,948
Shares available for grant         1,710,824      
2018 Equity Incentive Plan | Employee Stock Options                
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                
Total unrecognized compensation cost related to unvested granted         $ 18,200,000      
Remaining unrecognized compensation cost expected to be recognized over weighted-average period         2 years 3 months 18 days      
2018 Equity Incentive Plan | Restricted Stock Units                
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                
Total unrecognized compensation cost related to unvested granted         $ 5,100,000      
Remaining unrecognized compensation cost expected to be recognized over weighted-average period         2 years 8 months 12 days      
2018 Equity Incentive Plan | Employee Stock Purchase Plan                
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                
Unrecognized stock-based compensation expense         $ 100,000      
2018 Equity Incentive Plan | Maximum                
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                
Increase in stock reserved for issuance as percentage of capital stock outstanding on last day of preceding year   5.00%            
2018 Employee Stock Purchase Plan                
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                
Reserved common stock 230,000              
Annual increase period of common stock reserved for issuance 10 years              
Maximum number of shares issuable 2,300,000       361,539      
Shares available for grant         195,992 131,939    
Shares available for grant, increase               230,989
2018 Employee Stock Purchase Plan | Maximum                
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                
Increase in stock reserved for issuance as percentage of capital stock outstanding on last day of preceding year 1.00%              
Call Option Plan                
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                
Stock-based compensation expense         $ 109,000 $ 78,000 65,000  
Other expense net         $ 76,000 $ 153,000 $ 133,000  
Call Option Plan | Option Granted in February 2017                
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                
Share-based compensation arrangement by share-based payment award options, shares granted       248,944        
Call options expiration period       1 year        
Call Option Plan | Option Granted in August 2019                
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                
Share-based compensation arrangement by share-based payment award options, shares granted     17,780          
Call options expiration period     1 year          
Call Option Plan | January 1 , 2017 | Option Granted in February 2017                
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                
Call options vesting percentage       25.00%        
Call Option Plan | January 1 , 2018 | Option Granted in February 2017                
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                
Call options vesting percentage       25.00%        
Call Option Plan | January 1 , 2019 | Option Granted in February 2017                
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                
Call options vesting percentage       25.00%        
Call Option Plan | January 1 , 2019 | Option Granted in August 2019                
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                
Call options vesting percentage     25.00%          
Call Option Plan | January 1 , 2020 | Option Granted in February 2017                
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                
Call options vesting percentage       25.00%        
Call Option Plan | January 1 , 2020 | Option Granted in August 2019                
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                
Call options vesting percentage     25.00%          
Call Option Plan | January 1 , 2021 | Option Granted in August 2019                
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                
Call options vesting percentage     25.00%          
Call Option Plan | January 1 , 2022 | Option Granted in August 2019                
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                
Call options vesting percentage     25.00%          
Call Option Plan | Vaxcyte                
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                
Reserved common stock         266,724