Summary of Significant Accounting Policies - Additional Information (Details) - USD ($)	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Sep. 30, 2019
Summary Of Significant Accounting Policies [Line Items]
Grant revenue	$ 575,000	$ 575,000
Deferred offering costs	0	0
ADDF
Summary Of Significant Accounting Policies [Line Items]
Grant revenue	575,000	575,000
Keystone Capital Partners, LLC | ATM Facility | Additional Paid-in Capital
Summary Of Significant Accounting Policies [Line Items]
Deferred offering costs	$ 713,000	713,000
Vaccinex Products
Summary Of Significant Accounting Policies [Line Items]
Gain or loss from VIE		$ 0	$ 0