Company and Nature of Business - Additional Information (Details) $ / shares in Units, $ in Thousands		6 Months Ended		12 Months Ended
	Aug. 09, 2018 USD ($) $ / shares shares	Jun. 30, 2019 USD ($) $ / shares	Jun. 30, 2018 USD ($)	Dec. 31, 2018 USD ($) $ / shares	Dec. 31, 2017 USD ($)
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Cash flow from operations		$ (14,422)	$ (10,499)	$ (25,300)
Accumulated deficit		$ 234,662		216,767
Proceeds from capital contribution			12,000	$ 12,000	$ 12,000
Common stock, par value | $ / shares		$ 0.0001		$ 0.0001
Offering expenses			327
Repayment of convertible promissory note, related party			$ 4,000
IPO
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Common stock, par value | $ / shares	$ 0.0001
Public offering price, per share | $ / shares	$ 12.00
Net proceeds from initial public offering	$ 37,200
Underwriting discounts and commissions	2,800
Offering expenses	$ 2,700
Convertible preferred stock converted and reclassified into common stock | shares	7,039,155
Reverse stock split of common stock description	1-for-10
Reverse stock split of common stock	10
IPO | Vaccinex LLC | Convertible Promissory Notes
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Repayment of convertible promissory note, related party	$ 1,500
IPO | Common Stock
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of shares issued and sold | shares	3,333,334