Summary of Significant Accounting Policies - Additional Information (Details)						1 Months Ended			3 Months Ended		12 Months Ended
	Nov. 08, 2021	Aug. 03, 2020 USD ($)	May 08, 2020 USD ($)	Mar. 27, 2020 USD ($)	Jan. 21, 2020 shares	Sep. 30, 2020 USD ($)	Jul. 31, 2020 USD ($)	Jan. 31, 2020 USD ($)	Sep. 30, 2020 USD ($) shares	Jun. 30, 2020 USD ($) shares	Dec. 31, 2021 USD ($) Segment shares	Dec. 31, 2020 USD ($) shares	Dec. 31, 2019 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Sale of stock, consideration received												$ 37,600,000
Proceeds from private offering of common stock												11,475,000
Proceeds from capital contribution				$ 11,500,000
Deferred offering costs											$ 0	0
Asset impairment charges											$ 0	$ 0
Treasury stock repurchased | shares											0	0
Interest related to income taxes											$ 0
Penalties related to income taxes											$ 0
Number of operating segments | Segment											1
Right of use assets and corresponding lease liabilities											$ 300,000
PPP Loan
Summary Of Significant Accounting Policies [Line Items]
Debt instrument interest rate	1.00%		1.00%
Debenture maturity date	May 08, 2025		May 08, 2022
Amount of loan received			$ 1,133,600
PPP Loan | Five Star Bank
Summary Of Significant Accounting Policies [Line Items]
Amount of loan received			$ 1,100,000
Maximum
Summary Of Significant Accounting Policies [Line Items]
Sale of stock, consideration received						$ 113,000,000
Alzheimers Association
Summary Of Significant Accounting Policies [Line Items]
Grant revenue											0	$ 575,000
Common Stock
Summary Of Significant Accounting Policies [Line Items]
Proceeds from private offering of common stock						$ 2,000,000.0	$ 4,000,000.0	$ 7,500,000					$ 13,800,000
Open Market Sale Agreement
Summary Of Significant Accounting Policies [Line Items]
Sale of stock, consideration received											$ 31,900,000
Aggregate number of shares issued and sell | shares											5,937,900
Proceeds from the sale of shares									$ 12,300,000	$ 1,200,000
Open Market Sale Agreement | Common Stock
Summary Of Significant Accounting Policies [Line Items]
Aggregate number of shares issued and sell | shares									3,815,600	317,688
Stock Purchase Agreement | Keystone Capital Partners, LLC
Summary Of Significant Accounting Policies [Line Items]
Stock purchase program number of shares agree to purchase											$ 5,000,000.0
Proceeds from the sale of shares										$ 1,200,000	$ 300,000
Stock Purchase Agreement | Common Stock
Summary Of Significant Accounting Policies [Line Items]
Aggregate number of shares issued and sell | shares					1,468,563
Stock Purchase Agreement | Common Stock | Keystone Capital Partners, LLC
Summary Of Significant Accounting Policies [Line Items]
Aggregate number of shares issued and sell | shares										324,424	47,319
ATM Facility | Additional Paid-in Capital | Keystone Capital Partners, LLC
Summary Of Significant Accounting Policies [Line Items]
Deferred offering costs												713,000
Securities Purchase Agreement
Summary Of Significant Accounting Policies [Line Items]
Debt instrument interest rate		7.00%
Debt instrument principal amount		$ 8,640,000
Purchase price of convertible debentures		$ 8,000,000.0
Debt instrument, discount rate		8.00%
Debenture maturity date		Aug. 03, 2021
Vaccinex Products
Summary Of Significant Accounting Policies [Line Items]
Gain or loss from VIE											$ 0
Proceeds from capital contribution											$ 0	$ 0