Net Loss Per Share Attributable to Common Stockholders - Weighted-Average Common Stock Equivalents Excluded from Calculation of Diluted Net Loss Per Share as They Had Anti-Dilutive Effect (Details) - shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Convertible Preferred Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Weighted-average common stock equivalents excluded from calculation of diluted net loss per share		7,039,155
Employee Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Weighted-average common stock equivalents excluded from calculation of diluted net loss per share	432,051	424,843
Vaccinex Products, LP Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Weighted-average common stock equivalents excluded from calculation of diluted net loss per share	1,202,566	1,202,566
VX3 Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Weighted-average common stock equivalents excluded from calculation of diluted net loss per share	1,318,797	800,880