Common Stock Reserved For Issuance - Common Stock Reserved For Potential Future Issuances (Details) - shares	Sep. 30, 2021	Dec. 31, 2020
Class Of Stock [Line Items]
Total shares of common stock reserved	1,550,887	3,566,199
Shares Underlying Outstanding Stock Options
Class Of Stock [Line Items]
Total shares of common stock reserved	1,147,457	832,868
Shares Available For Future Stock Option Grants
Class Of Stock [Line Items]
Total shares of common stock reserved	403,430	267,275
Exchange of Vaccinex Products, LP Units
Class Of Stock [Line Items]
Total shares of common stock reserved		1,147,259
Exchange of VX3 Units
Class Of Stock [Line Items]
Total shares of common stock reserved		1,318,797