Vaccinex (VCNX) 10-K 9 Mar 20 2019 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2019	Mar. 05, 2020	Jun. 30, 2019
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Trading Symbol	VCNX
Entity Registrant Name	Vaccinex, Inc.
Entity Central Index Key	0001205922
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Seasoned Well Known Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Shell Company	false
Entity Ex Transition Period	false
Entity Public Float			$ 23,012,742
Entity Common Stock, Shares Outstanding		16,356,210
Entity File Number	001-38624
Entity Tax Identification Number	16-1603202
Entity Address, Address Line One	1895 Mount Hope Avenue
Entity Address, City or Town	Rochester
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	14620
City Area Code	585
Local Phone Number	271-2700
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Security Exchange Name	NASDAQ
Document Annual Report	true
Document Transition Report	false
Entity Incorporation, State or Country Code	DE

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 2,776,000	$ 5,618,000
Marketable securities	0	14,106,000
Accounts receivable	898,000	639,000
Prepaid expenses and other current assets	336,000	1,061,000
Total current assets	4,010,000	21,424,000
Property and equipment, net	594,000	604,000
TOTAL ASSETS	4,604,000	22,028,000
Current liabilities:
Accounts payable	3,208,000	2,322,000
Accrued expenses	3,670,000	4,364,000
TOTAL LIABILITIES	6,878,000	6,686,000
Commitments and contingencies (Note 9)
Stockholders’ equity (deficit):
Common stock, par value of $0.0001 per share; 100,000,000 shares authorized as of December 31, 2019 and 2018; 14,887,999 and 11,476,601 shares issued as of December 31, 2019 and 2018, respectively; 14,887,147 and 11,475,749 shares outstanding as of December 31, 2019 and 2018, respectively	1,000	1,000
Additional paid-in capital	222,403,000	208,156,000
Treasury stock, at cost; 852 shares of common stock as of December 31, 2019 and 2018, respectively	(11,000)	(11,000)
Accumulated deficit	(248,630,000)	(216,767,000)
Total Vaccinex, Inc. stockholders’ deficit	(26,237,000)	(8,621,000)
Noncontrolling interests	23,963,000	23,963,000
TOTAL STOCKHOLDERS’ EQUITY (DEFICIT)	(2,274,000)	15,342,000
TOTAL LIABILITIES, REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS’ EQUITY (DEFICIT)	$ 4,604,000	$ 22,028,000

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2019	Dec. 31, 2018
Statement Of Financial Position [Abstract]
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	14,887,999	11,476,601
Common stock, shares outstanding	14,887,147	11,475,749
Treasury stock, common shares	852	852

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Revenue	$ 523,000	$ 724,000
Costs and expenses:
Cost of revenue	199,000	1,033,000
Research and development	25,670,000	22,353,000
General and administrative	6,669,000	4,619,000
Total costs and expenses	32,538,000	28,005,000
Loss from operations	(32,015,000)	(27,281,000)
Change in fair value of derivative liabilities		369,000
Interest expense		(392,000)
Loss on extinguishment of related party convertible promissory note		(2,379,000)
Other income (expense), net	152,000	165,000
Loss before provision for income taxes	(31,863,000)	(29,518,000)
Provision for income taxes	0	0
Net loss	(31,863,000)	(29,518,000)
Net loss attributable to noncontrolling interests	0	0
Net loss attributable to Vaccinex, Inc. common stockholders	(31,863,000)	(29,518,000)
Comprehensive loss	$ (31,863,000)	$ (29,518,000)
Net loss per share attributable to Vaccinex, Inc. common stockholders, basic and diluted	$ (2.47)	$ (5.65)
Weighted-average shares used in computing net loss per share attributable to Vaccinex, Inc. common stockholders, basic and diluted	12,880,746	5,223,635

Consolidated Statements of Rede

Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	IPO	Redeemable Convertible Preferred Stock Series B, B-1, B-2, C, D	Redeemable Convertible Preferred Stock	Redeemable Convertible Preferred StockRedeemable Convertible Preferred Stock Series B, B-1, B-2, C, D	Convertible Preferred Stock	Convertible Preferred StockConvertible Preferred Stock Series A	Common Stock	Common StockIPO	Common StockRedeemable Convertible Preferred Stock Series B, B-1, B-2, C, D	Common StockConvertible Preferred Stock Series A	Additional Paid-in Capital	Additional Paid-in CapitalIPO	Additional Paid-in CapitalRedeemable Convertible Preferred Stock Series B, B-1, B-2, C, D	Additional Paid-in CapitalConvertible Preferred Stock Series A	Treasury Stock	Treasury StockRedeemable Convertible Preferred Stock Series B, B-1, B-2, C, D	Treasury StockRedeemable Convertible Preferred Stock	Treasury StockRedeemable Convertible Preferred StockRedeemable Convertible Preferred Stock Series B, B-1, B-2, C, D	Accumulated Deficit	Total Vaccinex,Inc. Stockholders' Deficit	Total Vaccinex,Inc. Stockholders' DeficitIPO	Total Vaccinex,Inc. Stockholders' DeficitRedeemable Convertible Preferred Stock Series B, B-1, B-2, C, D	Noncontrolling Interests
Balance at Dec. 31, 2017	$ (113,490)					$ 7,684						$ 54,123				$ (11)				$ (187,249)	$ (125,453)			$ 11,963
Balance, Shares at Dec. 31, 2017				53,089,959
Balance at Dec. 31, 2017				$ 111,718
Balance, Shares at Dec. 31, 2017						5,702,450		1,103,396								836		163
Initial public offering,net of issuance costs / Issuance of Common Shares		$ 34,450											$ 34,450									$ 34,450
Initial public offering,net of issuance costs / Issuance of Common Shares, Shares									3,333,334
Conversion of convertible preferred stock to common stock			$ 111,718		$ (111,718)		$ (7,684)			$ 1				$ 111,717	$ 7,684								$ 111,718
Conversion of convertible preferred stock to common stock, Shares					(53,089,959)		(5,702,450)			6,468,933	570,238						16		(163)
Capital contribution	12,000																							12,000
Exercise of stock options	$ 5											5									5
Exercise of stock options, Shares	700							700
Stock-based compensation	$ 177											177									177
Net loss	(29,518)																			(29,518)	(29,518)
Balance at Dec. 31, 2018	15,342							$ 1				208,156				$ (11)				(216,767)	(8,621)			23,963
Balance, Shares at Dec. 31, 2018								11,476,601								852
Initial public offering,net of issuance costs / Issuance of Common Shares	13,800											13,800									13,800
Initial public offering,net of issuance costs / Issuance of Common Shares, Shares								3,382,332
Conversion of Vaccinex Products LP Units into common shares, Shares								29,066
Stock-based compensation	447											447									447
Net loss	(31,863)																			(31,863)	(31,863)
Balance at Dec. 31, 2019	$ (2,274)							$ 1				$ 222,403				$ (11)				$ (248,630)	$ (26,237)			$ 23,963
Balance, Shares at Dec. 31, 2019								14,887,999								852

Consolidated Statements of Re_2

Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity Deficit (Parenthetical) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)
IPO
Initial public offering, issuance costs	$ 5,551

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (31,863)	$ (29,518)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	249	223
Amortization of debt discount		308
Net amortization of premiums and discounts on marketable securities	(44)	(100)
Stock-based compensation	447	177
Change in fair value of derivative liabilities		(369)
Loss on extinguishment of related party convertible promissory note		2,379
Changes in operating assets and liabilities:
Accounts receivable	(260)	(522)
Prepaid expenses and other current assets	725	(384)
Accounts payable	725	421
Accrued expenses	(694)	2,407
Deferred revenue		(298)
Net cash used in operating activities	(30,715)	(25,276)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of marketable securities		(20,756)
Sales of marketable securities	14,151	6,750
Purchase of property and equipment	(78)	(235)
Net cash provided by (used in) investing activities	14,073	(14,241)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from initial public offering of common stock, net of commissions and underwriting discounts		37,125
Proceeds from private offering of common stock	13,800
Payments of initial public offering costs		(2,675)
Proceeds from exercise of stock options		5
Repayment of convertible promissory note, related party		(5,500)
Proceeds from capital contribution		12,000
Net cash provided by financing activities	13,800	40,955
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	(2,842)	1,438
CASH AND CASH EQUIVALENTS–Beginning of period	5,618	4,180
CASH AND CASH EQUIVALENTS–End of period	2,776	5,618
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Cash paid for interest		275
SUPPLEMENTAL DISCLOSURES OF NONCASH INVESTING AND FINANCING ACTIVITIES:
Purchase of property and equipment in accounts payable	$ 161
Conversion of redeemable convertible preferred stock into common stock		111,718
Conversion of convertible preferred stock into common stock		$ 7,684

Company and Nature of Business

Company and Nature of Business	12 Months Ended
	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Company and Nature of Business	1. COMPANY AND NATURE OF BUSINESS Vaccinex, Inc. (together with its subsidiaries, the Company) was incorporated in Delaware in April 2001 and is headquartered in Rochester, New York. The Company is a clinical-stage biotechnology company engaged in the discovery and development of targeted biotherapeutics to treat serious diseases and conditions with unmet medical needs, including cancer, neurodegenerative diseases, and autoimmune disorders. Since its inception, the Company has devoted substantially all of its efforts toward product research and development, marketing development and raising capital. The Company is subject to a number of risks common to other early-stage biotechnology companies including, but not limited to, the successful development and commercialization of its product candidates, rapid technological change and competition, dependence on key personnel and collaborative partners, uncertainty of protection of proprietary technology and patents, clinical trial uncertainty, fluctuation in operating results and financial performance, the need to obtain additional funding, potential product liability, compliance with governmental regulations, technological and medical risks, customer demand, management of growth and effectiveness of marketing by the Company. If the Company does not successfully commercialize or partner any of its product candidates, it will be unable to generate product revenue or achieve profitability. Going Concern These consolidated financial statements have been prepared on a going concern basis, which implies the Company will continue to realize its assets and discharge its liabilities in the normal course of business. The Company has incurred significant losses and negative cash flows from operations since inception and expects to incur additional losses until such time that it can generate significant revenue from the commercialization of its product candidates. The Company had negative cash flow from operations of $30.7 million and $25.3 million for the years ended December 31, 2019 and 2018, respectively, and an accumulated deficit of $248.6 million and $216.8 million as of December 31, 2019 and 2018, respectively. These conditions raise substantial doubt about the Company’s ability to continue as a going concern within one year after the date that the consolidated financial statements are issued. The consolidated financial statements do not include any adjustments relating to the recoverability and classification of recorded asset amounts or the amounts and classification of liabilities that might result from the outcome of this uncertainty. To date, the Company has relied on equity and debt financing to fund its operations. During the year ended December 31, 2018 the Company received a $12.0 million capital contribution from noncontrolling interests. Additionally, the Company completed a private placement of its common stock for gross proceeds of $13.8 million during the third quarter of 2019, as well as an additional private placement of its common stock for gross proceeds of $7.5 million in January 2020. Because the Company’s product candidates are still in the early stages of development, substantial additional financing will be needed by the Company to fund its operations and ongoing research and development efforts prior to the commercialization, if any, of its product candidates. Given the Company’s projected operating requirements and its existing cash and cash equivalents, the Company needs additional financing during 2020 in order to continue operations. Management is currently evaluating different strategies to obtain the required funding of future operations. These strategies may include, but are not limited to, additional funding from current or new investors, refinancing of existing debt obligations or obtaining additional debt financing. There can be no assurances that the Company will be able to secure such additional financing, or if available, that it will be sufficient to meet its needs or on favorable terms. Because management’s plans have not yet been finalized and are not within the Company’s control, the implementation of such plans cannot be considered probable. As a result, the Company has concluded that management’s plans do not alleviate substantial doubt about the Company’s ability to continue as a going concern. Initial Public Offering In August 2018, the Company completed its initial public offering (the “IPO”) in which it issued and sold 3,333,334 shares of its common stock, $0.0001 par value, at a public offering price of $12.00 per share. The Company received net proceeds of $37.2 million after deducting underwriting discounts and commissions of $2.8 million, but before deducting offering expenses of $2.7 million. In addition, in connection with the IPO: • all shares of the Company’s then-outstanding convertible preferred stock were automatically converted and reclassified into 7,039,155 shares of its common stock, $0.0001 par value; • a 1-for-10 reverse stock split of the Company’s common stock was affected; and • the Company repaid a $1.5 million convertible promissory note issued in June 2016 (the “June 2016 Note”), held by a related party, Vaccinex (Rochester), L.L.C. (“Vaccinex LLC”), which is majority owned and controlled by Dr. Maurice Zauderer, the Company’s President, Chief Executive Officer and a member of its board of directors.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. The accompanying consolidated financial statements reflect the consolidated application of certain significant accounting policies, as described below and elsewhere in the accompanying notes to the consolidated financial statements. Basis of Presentation and Consolidation These consolidated financial statements reflect the accounts and operations of the Company and those of its subsidiaries in which the Company has a controlling financial interest. As of December 31, 2019, and 2018, the Company’s accounts include Vaccinex Products and VX3 (DE) LP, a Delaware limited partnership (VX3). VX3 was established in October 2017 by a group of Canadian investors and was determined to be a variable interest entity (“VIE”) in which the Company is the primary beneficiary. The Company consolidates any VIE of which it is the primary beneficiary. The Company presents its noncontrolling interests as a separate component of stockholders’ equity (deficit). The company presents the net loss of VX3 equal to the percentage ownership interest retained in such entity by the respective noncontrolling party (VX3), and as a separate component within its consolidated statements of operations and comprehensive loss. The financial position of Vaccinex Products was not material as of December 31, 2019 and 2018, and there were no gains or losses for Vaccinex Products for the years ended December 31, 2019 and 2018. Intercompany transactions and balances have been eliminated. Use of Estimates These consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”). The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities as of the date of the consolidated financial statements and the reported amount of expenses during the reporting period. Such management estimates include those relating to assumptions used in the valuation of stock option awards, the valuation of derivative instruments, and valuation allowances against deferred income tax assets. Actual results could differ from those estimates. Cash and Cash Equivalents The Company considers all highly liquid investments with an original maturity of three months or less at the date of purchase to be cash equivalents. The Company deposits its cash primarily in checking and money market accounts. Concentration of Credit Risk, Other Risks and Uncertainties Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash and cash equivalents. Cash equivalents are deposited in interest-bearing money market accounts. Although the Company deposits its cash with multiple financial institutions, cash balances may occasionally be in excess of the amounts insured by the Federal Deposit Insurance Corporation. Management believes the financial risk associated with these balances is minimal and has not experienced any losses to date. The Company depends on third-party manufacturers for the manufacture of drug substance and drug product for clinical trials. The Company also relies on certain third parties for its supply chain. Disputes with these third- party manufacturers or shortages in goods or services from third-party suppliers could delay the manufacturing of the Company’s product candidates and adversely impact its results of operations. Marketable Securities Marketable securities consist of investments with original maturities greater than 90 days at their acquisition date. The Company classifies all of its marketable securities as available-for-sale securities. The Company’s marketable securities are measured and reported at fair value using quoted prices in active markets for similar securities. Unrealized gains and losses on available-for-sale securities are reported as accumulated other comprehensive loss. The cost of securities sold is determined on a specific identification basis, and realized gains and losses are included in other income (expense), net in the consolidated statements of operations and comprehensive loss. The Company evaluates its marketable securities with unrealized losses for other-than-temporary impairment. When assessing marketable securities for other-than-temporary declines in value, the Company considers such factors as, among other things, how significant the decline in value is as a percentage of the original cost, how long the market value of the investment has been less than its original cost, the Company’s ability and intent to retain the investment for a period of time sufficient to allow for any anticipated recovery in fair value and market conditions in general. If any adjustment to fair value reflects a decline in the value of the investment that the Company considers to be “other-than-temporary,” the Company reduces the investment to fair value through a charge to the statement of operations and comprehensive loss. No such adjustments were necessary during the periods presented. Fair Value of Financial Instruments Financial instruments consist of cash and cash equivalents, marketable securities, prepaid expenses and other current assets, accounts payable, accrued expenses, convertible promissory notes, and derivative liabilities. Cash equivalents and marketable securities are stated at fair value. Prepaid expenses and other current assets, accounts payable and accrued expenses are stated at their carrying value, which approximates fair value due to the short time to the expected receipt or payment date. The principal amount of the Company’s convertible promissory notes approximates fair value as the stated interest rate approximates market rates currently available to the Company. The derivative liabilities are stated were stated at fair value prior to their extinguishment in 2018. Property and Equipment, Net Property and equipment are recorded at cost. Depreciation is computed over estimated useful lives of the related assets using the straight-line method. Leasehold improvements are amortized on a straight-line basis over the shorter of the useful life or term of the lease. Upon retirement or disposal, the cost and related accumulated depreciation are removed from the consolidated balance sheets and the resulting gain or loss is recorded to general and administrative expense in the consolidated statements of operations. Routine expenditures for maintenance and repairs are expensed as incurred. Estimated useful lives for property and equipment are as follows: Property and Equipment Estimated Useful Life Research equipment 5 years Furniture and fixtures 5 years Computer equipment 3 years Leasehold improvements Lesser of estimated useful life or remaining lease term Impairment of Long-Lived Assets The Company reviews the recoverability of its long-lived assets when events or changes in circumstances occur that indicate that the carrying value of the asset may not be recoverable. The assessment of possible impairment is based on the ability to recover the carrying value of the assets from the expected future cash flows (undiscounted and without interest expense) of the related operations. If these cash flows are less than the carrying value of such assets, an impairment loss for the difference between the estimated fair value and carrying value is recorded. There was no impairment loss recognized during the years ended December 31, 2019 and 2018. Derivative Liabilities The Company had outstanding derivative instruments related to certain features embedded within the Company’s outstanding convertible promissory notes, and an outstanding derivative instrument related to an arrangement providing a holder of one of the Company’s convertible promissory notes an option to purchase shares of equity in a future qualifying financing event. These derivatives were accounted for as derivative liabilities and remeasured to fair value as of each balance sheet date and the related remeasurement adjustments are recognized in the consolidated statements of operations. The Company recorded adjustments to the fair value of the derivative liabilities until the repayment of the related convertible promissory notes as discussed further in Note 8. Treasury Stock The Company records treasury stock activities under the cost method whereby the cost of the acquired stock is recorded as treasury stock. The Company’s accounting policy upon the formal retirement of treasury stock is to deduct the par value from common stock and to reflect any excess of cost over par value as a reduction to additional paid-in capital (to the extent created by previous issuances of the shares) and then retained earnings. There was no treasury stock repurchased for the years ended December 31, 2019 and 2018. Revenue Recognition The Company’s revenues are generated primarily through collaborative research, license, development and commercialization agreements. We recognize revenue when our customers obtain control of promised goods or services, in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of ASC 606, the entity performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. At contract inception, once the contract is determined to be within the scope of ASC 606, the Company assesses the goods or services promised within each contract and determines those that are performance obligations and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. Arrangements that include rights to additional goods or services that are exercisable at a customer’s discretion are generally considered options. We assess if these options provide a material right to the customer and if so, they are considered performance obligations. The exercise of a material right is accounted for as a contract modification for accounting purposes. The Company recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) each performance obligation is satisfied at a point in time or over time, and if over time this is based on the use of an output or input method. Amounts received prior to revenue recognition are recorded as deferred revenue. Amounts expected to be recognized as revenue within the 12 months following the balance sheet date are classified as current portion of deferred revenue in the accompanying consolidated balance sheets. Amounts not expected to be recognized as revenue within the 12 months following the balance sheet date are classified as deferred revenue, net of current portion. Amounts recognized as revenue, but not yet received or invoiced are generally recognized as contract assets in the Other Assets line item in the Consolidated Balance Sheets. Collaborative Arrangements – The Company has entered into collaboration agreements, which are within the scope of ASC 606, to discover, develop, manufacture and commercialize product candidates. The terms of these agreements typically contain multiple promises or obligations, which may include: (1) licenses, or options to obtain licenses, to use the Company’s research program materials, and (2) research and development activities to be performed on behalf of the collaboration partner. Payments the Company receives under these arrangements typically include one or more of the following: non-refundable, upfront license fees; option exercise fees; funding of research and/or development efforts; clinical and development, regulatory, and sales milestone payments; and royalties on future product sales. The Company analyzes its collaboration arrangements to assess whether they are within the scope of ASC 808, Collaborative Arrangements For a complete discussion of accounting for collaboration revenues, see Note 7, “Collaboration and license agreements”. Research and Development Costs Expenditures, including payroll, contractor expenses and supplies, for research and development of products are expensed as incurred. Clinical trial and other development costs incurred by third parties are expensed as the contracted work is performed. Where contingent milestone payments are due to third parties under research and development arrangements, the milestone payment obligations are expensed when the milestone results are probable of being achieved. Stock-Based Compensation The Company utilizes the Black-Scholes stock option-pricing model as the method for estimating the grant date fair value of its stock option awards. The Black-Scholes stock option-pricing model requires the use of highly subjective and complex assumptions, including the stock options’ expected term and the price volatility of the underlying stock. The grant date fair value of the portion of the stock option award that is ultimately expected to vest is recognized as compensation expense over the stock option awards’ requisite service periods. The Company recognizes stock-based compensation to expense using the straight-line method over the requisite service period. If there are any modifications or cancelations of stock option awards, the Company may be required to accelerate, increase or decrease any remaining unrecognized stock-based compensation expense. Income Taxes The Company uses the asset and liability method of accounting for income taxes. Deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to temporary differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities, which relate primarily to the carrying amount of the Company’s property and equipment and its net operating loss carryforward, are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. Deferred tax expense or benefit is the result of changes in the deferred tax assets and liabilities. Valuation allowances are established when necessary to reduce deferred tax assets where, based upon the available evidence, management concludes that it is more likely than not that the deferred tax assets will not be realized. In evaluating its ability to recover deferred tax assets, the Company considers all available positive and negative evidence, including its operating results, ongoing tax planning and forecasts of future taxable income on a jurisdiction-by-jurisdiction basis. Because of the uncertainty of the realization of the deferred tax assets, the Company has recorded a full valuation allowance against its deferred tax assets. Reserves are provided for tax benefits for which realization is uncertain. Such benefits are only recognized when the underlying tax position is considered more likely than not to be sustained on examination by a taxing authority, assuming they possess full knowledge of the position and facts. Interest and penalties related to uncertain tax positions are recognized in the provision for income taxes; however, the Company currently has no interest or penalties related to income taxes. Segment and Geographic Information The Company’s chief operating decision maker, its Chief Executive Officer, reviews its operating results on an aggregate basis for purposes of allocating resources and evaluating financial performance. The Company has one business activity, the discovery and development of targeted biotherapeutics to treat serious diseases and conditions with unmet medical needs, and there are no segment managers who are held accountable for operations or operating results. Accordingly, the Company operates in one segment. As of December 31, 2019, and 2018, all long-lived assets are located in the United States. Net Loss Per Share Attributable to Vaccinex, Inc. Common Stockholders The Company calculates its basic and diluted net loss per share attributable to Vaccinex, Inc. common stockholders in conformity with the two-class method required for companies with participating securities. The Company considers all series of its preferred stock to be participating securities. In the event a dividend is declared or paid on the Company’s common stock, holders of preferred stock are entitled to a proportionate share of such dividend in proportion to the holders of common stock on an as-if converted basis. Under the two-class method, basic net loss per share attributable to Vaccinex, Inc. common stockholders is calculated by dividing the net loss attributable to Vaccinex, Inc. common stockholders by the weighted-average number of shares of common stock outstanding for the period. Net loss attributable to Vaccinex, Inc. common stockholders is determined by allocating undistributed earnings between common and preferred stockholders. The diluted net loss per share attributable to Vaccinex, Inc. common stockholders is computed by giving effect to all potential dilutive common stock equivalents outstanding for the period determined using the treasury stock method. The net loss attributable to Vaccinex, Inc. common stockholders was not allocated to the preferred stock under the two-class method as the preferred stock do not have a contractual obligation to share in the Company’s losses. For purposes of this calculation, redeemable convertible preferred stock, convertible preferred stock, and stock options to purchase common stock are considered common stock equivalents but have been excluded from the calculation of diluted net loss per share attributable to Vaccinex, Inc. common stockholders as their effect is anti-dilutive. Recent Accounting Pronouncements Not Yet Adopted In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) Leases, Targeted Improvements to ASC 842, Leases , Leases The Company is currently evaluating the potential impact ASU 2016-02 may have on its financial position, results of operations, and related footnotes. The Company expects it will elect to utilize the available package of practical expedients permitted under the transition guidance within the new standard, which does not require the reassessment of the following: i) whether existing or expired arrangements are or contain a lease, ii) the lease classification of existing or expired leases, and iii) whether previous initial direct costs would qualify for capitalization under the new lease standard. Additionally, the Company expects it will make an accounting policy election to keep leases with an initial term of 12 months or less off of its balance sheet. The Company’s assessment will include, but is not limited to, evaluating the impact that this standard has on the lease of its corporate headquarters in Rochester, New York. Recently Adopted Accounting Pronouncements In May 2014, FASB issued ASU No. 2014-09, Revenue (ASC 606): Revenue from Contracts with Customers Revenue Recognition In November 2018, the FASB issued ASU No. 2018-18, Collaborative Arrangements (Topic 808)—Clarifying the Interaction between Topic 808 and ASC 606

Balance Sheet Components

Balance Sheet Components	12 Months Ended
	Dec. 31, 2019
Balance Sheet Related Disclosures [Abstract]
Balance Sheet Components	3. Property and Equipment Property and equipment consist of the following (in thousands): As of December 31, 2019 As of December 31, 2018 Leasehold improvements $ 3,161 $ 3,145 Research equipment 3,442 3,219 Furniture and fixtures 350 350 Computer equipment 214 214 Property and equipment, gross 7,167 6,928 Less: accumulated depreciation and amortization (6,573 ) (6,324 ) Property and equipment, net $ 594 $ 604 Depreciation and amortization expense related to property and equipment was $249,000 and $223,000 for the years ended December 31, 2019 and 2018, respectively. Accrued Expenses Accrued expenses consist of the following (in thousands): As of December 31, 2019 As of December 31, 2018 Accrued clinical trial cost $ 3,252 $ 3,796 Accrued payroll and related benefits 79 296 Accrued consulting and legal 262 236 Accrued other 77 36 Accrued expenses $ 3,670 $ 4,364

Marketable Securities

Marketable Securities	12 Months Ended
	Dec. 31, 2019
Investments Debt And Equity Securities [Abstract]
Marketable Securities	4. MARKETABLE SECURITIES As of December 31, 2019, the Company did not hold any marketable securities. The fair value of available-for-sale marketable securities as of December 31, 2018, was as follows (in thousands): December 31, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Marketable securities: U.S. Treasury securities $ 14,106 $ - $ - $ 14,106 $ 14,106 $ - $ - $ 14,106

Fair Value of Financial Measure

Fair Value of Financial Measurements	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value of Financial Measurements	5. Assets and liabilities recorded at fair value on a recurring basis in the consolidated balance sheets are categorized based upon the level of judgment associated with the inputs used to measure their fair values. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. ASC 820 describes a fair value Level 1 – Quoted prices in active markets for identical assets or liabilities. Level 2 – Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 – Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The assets’ or liabilities’ fair value measurement level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. The following table sets forth the fair value of the Company’s financial assets by level within the fair value hierarchy (in thousands): As of December 31, 2019 Fair Value Level 1 Level 2 Level 3 Financial Assets: Cash equivalents: Money market fund $ 1,464 $ 1,464 $ - $ - Total Financial Assets $ 1,464 $ 1,464 $ - $ - As of December 31, 2018 Fair Value Level 1 Level 2 Level 3 Financial Assets: Cash equivalents: Money market fund $ 4,881 $ 4,881 $ - $ - Marketable securities: U. S. Treasury securities $ 14,106 $ - $ 14,106 $ - Total Financial Assets $ 18,987 $ 4,881 $ 14,106 $ - The Company did not transfer any assets measured at fair value on a recurring basis to or from Level 1 and Level 2 during the years ended December 31, 2019 and 2018, other than the monetizing of the U.S. treasury securities during the year ended December 31, 2019.

License and Services Agreement

License and Services Agreement	12 Months Ended
	Dec. 31, 2019
Research And Development [Abstract]
License and Services Agreement	6 . LICENSE AND SERVICES AGREEMENT In November 2017, the Company entered into a license agreement (the “VX3 License Agreement”) with VX3 (DE) LLP (“VX3”), which was formed by a group of Canadian investors including the Company’s majority stockholder, FCMI Parent Co. (“FCMI Parent”). VX3 was created for the purpose of funding the Company’s research and development activities for pepinemab, our most advanced product candidate. Under the VX3 License Agreement, the Company granted VX3 the license to use, make, have made, sell, offer and import pepinemab for the treatment of Huntington’s disease in the U.S. and Canada and, in return, VX3 agreed to fund research and development activities with up to an aggregate of $32.0 million in milestone payments to the Company and to share any pepinemab profits and sublicensing revenue under the agreement in an amount based on a calculation set forth in the agreement. The Company also entered into a services agreement with VX3 (the “Services Agreement”), pursuant to which the Company will carry out development activities for pepinemab for the treatment of Huntington’s disease in the U.S. and Canada in exchange for services payments from VX3, including a payment of $11.9 million in 2017. The VX3 License Agreement expires upon the last to expire licensed patent and may be terminated by either party upon uncured material breach, the occurrence of certain transactions or financings including the consummation of an initial public offering by the Company, uncured failure of VX3 to make any payment due under the Services Agreement, or upon written notice after November 6, 2020. The Services Agreement may be terminated by either party upon an uncured material breach and is automatically terminated upon termination of the VX3 License Agreement. The VX3 License Agreement provides that upon termination, the Company will issue to VX3 or its designees the number of shares of the Company’s common stock equal to the lesser of (1) the aggregate of all payments made to VX3 by its partners divided by $18.20 and (2) the then fair market value of VX3 divided by the then fair market value of one share of the Company’s common stock. The Company has a variable interest in VX3 through FCMI Parent, which is majority owned and controlled by the Company’s chairman, and it controlled 90% of VX3’s voting interest as of December 31, 2019 and 2018. VX3 does not have any business operations or generate any income or expenses and is primarily a funding mechanism specifically for the benefit of the Company, as its only activities consist of the receipt of funding and the contribution of such funding to the Company. Therefore, the Company determined that it is the primary beneficiary of VX3 and that the operating results of VX3 should be incorporated into the Company’s consolidated financial statements accordingly. In February, May and June 2018, the Services Agreement was amended to allow VX3 to provide additional funding for future research and development activities to take place in the year ended December 31, 2018 and to repay an outstanding convertible note in the amount of $4.0 million (Note 8). No other terms of the Services Agreement have since been amended; therefore, the above assessment resulting in the Company being the primary beneficiary of the VX3 entity remained unchanged as of December 31, 2018. The Company entered into an exchange agreement on August 13, 2018 with VX3 and its partners, including FCMI Parent, that provides each VX3 partner with the right to exchange all, but not less than all, of its partnership interests in VX3 for shares of the Company’s common stock. The exchange agreement also provides that FCMI Parent’s exercise of its option to exchange its VX3 partnership interests for shares of Company common stock, would trigger the exchange of all VX3 partnership interests for shares of Company common stock. Further, under the exchange agreement, the Company will have a right to require the exchange of all partnership interests in VX3 for shares of Company common stock in any of the following circumstances: • The Company enters into a transaction such as a sale, merger or consolidation such that shares of Company common stock are or will be sold or exchanged for cash and/or marketable securities; • On or after August 13, 2023; or • either the Company or VX3 enters into a licensing, partnering or similar transaction with respect to one or more products and indications licensed to VX3 by the Company, and all amounts then due and owing to VX3 in connection with such transaction have been paid to VX3. For the year ended December 31, 2018, the Company recorded the gross proceeds of $12.0 million, received from VX3 as capital contributions from noncontrolling interests on the consolidated financial statements. Noncontrolling equity interests do not participate in a proportionate share of the Company’s net losses for the year ended December 31, 2019 or December 31, 2018, respectively, pursuant to the aforementioned partnership, license, services and exchange agreements.

Collaboration Agreements

Collaboration Agreements	12 Months Ended
	Dec. 31, 2019
Collaboration Agreements [Abstract]
Collaboration Agreements	7 . COLLABORATION AGREEMENTS Merck Sharp & Dohme Corp. In September 2017, the Company entered into a research agreement with Merck Sharp & Dohme Corp. (“Merck”) to test vaccinia strain Modified Vaccinia Ankara. Under the research agreement, the Company designed genetic sequence for all constructs listed in the agreement and conducted research in accordance with the research protocol and a mutually agreed scope of work outlined in the agreement. Merck supplied the Company sufficient samples of the antibodies to carry out the research and has sole ownership of all right, title, interest and copy rights of the research results. Under the research agreement, the Company recognized service revenue of $69,000 for the year ended December 31, 2018. The research agreement expired in accordance with its terms in June 2018. In the fourth quarter of 2018, the Company entered into a second research agreement with Merck to test these antigen particles in an antibody discovery campaign. This second research agreement entailed a cost sharing feasibility study, which concluded during the second quarter of 2019. Surface Oncology, Inc. In November 2017, the Company entered into a research collaboration and license option agreement with Surface Oncology, Inc. (“Surface”) to identify and select antibodies against two target antigens, using the Company’s proprietary technology as described in the agreement. The term for each research program is nine to twelve months (not exceeding twelve months unless extended by written agreement) including time necessary for any functional assessment conducted by Surface following the commencement of the research program. Surface will provide the Company material to carry out the research activities. During the research program term, the Company also grants Surface non-exclusive, worldwide, limited-purpose license for each target to use the Company’s research program materials for conducting the research work pursuant to the agreement. Under the agreement, Surface may purchase exclusive options, exercisable by providing a written notice to the Company, to obtain (i) an exclusive product license to make, use, sell and import products incorporating antibodies targeting the first antigen and (ii) an exclusive research tool license to use antibodies targeting the second antigen to perform research. Surface purchased the first option and exercised the second option and entered into an exclusive research tool license agreement with Surface in the third quarter of 2019. Under the research collaboration and license option agreement, Surface paid an upfront technology access fee of $250,000 and makes milestone payments upon completion of each of four designated milestones for the first target antigen specified in the agreement. For the second target antigen, Surface is obligated to make payments to the Company based on time incurred by the Company in the conduct of the work plan described in the agreement. Surface is required to reimburse the Company for expenses incurred (i) in the conduct of the work plan as detailed in the research funding budget and (ii) for patent filings and prosecution of the Company’s program intellectual property as described in the agreement. The exercise of each option would also entail a license fee and annual maintenance fees, and in the case of the product license, royalties and additional milestone payments. During the year ended December 31, 2017, the Company received the upfront technology access fee of $250,000, of which the remaining $229,166 was recognized as revenue from the amortization of this upfront fee for the year ended December 31, 2018. The Company also received service fee payments of $123,276 and $282,171 for work conducted under the agreement for the years ended December 31, 2019 and 2018, respectively. This agreement will expire upon the latest of the expiration of both research programs and all evaluation and testing periods. During the year ended December 31, 2019, the Company recorded $400,000 of revenue related to its agreement with Surface, of which $300,000 was due to the purchase by Surface of its exclusive product license option and $100,000 was for the exclusive research tool license. There were no revenues from the exercise of product options in the year ended December 31, 2018. Heptares Therapeutics, Ltd. In June 2018, the Company entered into a research service agreement with Heptares Therapeutics, Ltd. (“Heptares”) to provide research services to Heptares. Under the agreement, Heptares provides the Company compounds, materials or samples, and the Company performs feasibility services to allow Heptares to evaluate the feasibility of the Company’s technology. The Company recognized service revenue of $138,556 from the Heptares research agreement for the year ended December 31, 2018.

Convertible Promissory Notes

Convertible Promissory Notes	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Convertible Promissory Notes	8 . CONVERTIBLE PROMISSORY NOTES As of December 31, 2019, the Company did not have any convertible promissory notes outstanding. See “Repayment of Convertible Promissory Notes” below. June 2016 Note In June 2016, the Company issued a $1.5 million convertible promissory note to a related party (the June 2016 Note). January 2017 Notes In January 2017, the Company entered into a convertible promissory note agreement whereby it agreed to issue, in the aggregate, $10.0 million of convertible promissory notes to a related party (the “January 2017 Notes”). The $4.0 million of the January 2017 Notes issued in January 2017 did not accrue interest, but the other $6.0 million of the January 2017 Notes issued in April, August and October 2017 accrued interest at an annual rate of 2%. The January 2017 Notes had a maturity date three years from issuance. Upon maturity, the holder of these convertible promissory notes was to be repaid the outstanding principal plus all accrued interest. The Company was also authorized to prepay the January 2017 Notes, plus accrued interest, without penalty. The debt issuance costs for these convertible promissory notes were not material. Of the January 2017 Notes, $6.0 million were paid in 2017 and the balance was paid in full on March 8, 2018. See “Repayment of Convertible Promissory Notes” below. Derivative Liabilities From the proceeds of the convertible promissory notes, the portion equal to the fair value of the embedded derivative liabilities and the option derivative at the time of each respective issuance was recognized as a debt discount to be amortized to interest expense over the term of the related convertible promissory notes. The Company recognized interest expense of $308,000 for the amortization of the debt discounts during the year ended December 31, 2018. Repayment of Convertible Promissory Notes Of the January 2017 Notes, $2.0 million issued in April 2017 was repaid along with accrued interest in May 2017, $4.0 million issued in August and October 2017 was repaid along with accrued interest in November 2017 and $4.0 million issued in January 2017 was repaid in March 2018. The option arrangement associated with the January 2017 Notes was also waived upon the repayment of the January 2017 Notes. As a result of this repayment, the related $0.3 million derivative liabilities associated with the conversion feature and the option arrangement were written off and the $2.2 million unamortized debt discount was recognized as a loss on extinguishment of related party convertible promissory note in the consolidated statements of operations in the year ended December 31, 2018. The June 2016 Note was repaid along with accrued interest in August 2018. As a result of this repayment, the related $31,000 derivative liability associated with the conversion feature and the option arrangement was written off and the $199,000 unamortized debt discount was recognized as a loss on extinguishment of related party convertible promissory note in the consolidated statements of operations in the year ended December 31, 2018.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	9 . COMMITMENTS AND CONTINGENCIES Sublicense Termination Payments In 2006, the Company licensed certain technology to EUSA Pharma SAS (“EUSA”) and in 2008, this technology was sublicensed by EUSA to Glaxo Group Limited (“GSK”) for development. GSK terminated its sub-license with EUSA in March 2010 and ownership of the technology reverted back to the Company. The Company may be required to pay EUSA up to $25.5 million plus ongoing royalty payments of 1% of net sales upon the occurrence of certain events involving the previously licensed technology, including Phase 3 clinical trial, FDA acceptance and approval and product sales. The Company is not planning any further commercialization efforts related to the previously licensed technology, and therefore does not anticipate any of the above described amounts will be paid. Operating Lease The Company leases its facilities from 1895 Management, Ltd., a New York corporation controlled by an entity affiliated with a director of the Company, under non-cancellable operating leases. Following entry into a lease extension agreement in July 2018, the lease agreement requires monthly rental payments of $14,000 through October 31, 2020. The Company is responsible for all maintenance, utilities, insurance and taxes related to the facility. As of December 31, 2019, the future minimum payments for the operating leases total $140,000 in 2020 and $0 for years 2021 through 2024. Rent expense incurred under the operating lease was $168,000 for each of the years ended December 31, 2019 and 2018 and is a component of general and administrative expense. Contingencies The Company is subject to claims and assessments from time to time in the ordinary course of business. The Company records a provision for a liability when it believes that it is both probable that a liability has been incurred and the amount can be reasonably estimated. Significant judgment is required to determine both probability and the estimated amount. In the normal course of business, the Company may become involved in legal proceedings. The Company will accrue a liability for such matters when it is probable that a liability has been incurred and the amount can be reasonably estimated. When only a range of possible loss can be established, the most probable amount in the range is accrued. If no amount within this range is a better estimate than any other amount within the range, the minimum amount in the range is accrued. The accrual for a litigation loss contingency might include, for example, estimates of potential damages, outside legal fees and other directly related costs expected to be incurred. As of December 31, 2019, and 2018, the Company was not involved in any material legal proceedings.

Common Stock Reserved For Issua

Common Stock Reserved For Issuance	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Common Stock Reserved For Issuance	1 0 . COMMON STOCK RESERVED FOR ISSUANCE Common stock has been reserved for the following potential future issuances: As of December 31, 2019 As of December 31, 2018 Shares underlying outstanding stock options 579,731 405,683 Shares available for future stock option grants 230,952 423,000 Exchange of Vaccinex Products, LP units 1,173,500 1,202,566 Conversion of VX3 units 1,318,797 1,318,797 Total shares of common stock reserved 3,302,980 3,350,046

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	1 1 . STOCK-BASED COMPENSATION 2011 Employee Equity Plan The Company’s 2011 Employee Equity Plan (the “2011 Plan”) was terminated in connection with the adoption of the Company’s 2018 Omnibus Incentive Plan (the “2018 Plan”) in August 2018, and the Company will not grant any additional stock options under the 2011 Plan. However, the 2011 Plan will continue to govern the terms and conditions of the outstanding stock options previously granted thereunder. Stock options granted under the 2011 Plan expire in five or ten years from the date of grant. 2018 Omnibus Incentive Plan In August 2018, the Company’s Board of Directors adopted, and its stockholders approved, the 2018 Plan, which allows for the granting of stock, stock option, and stock appreciation rights awards to employees, advisors and consultants. Stock options granted under the 2018 Plan may be either incentive stock options or non-statutory stock options. Incentive stock options may be granted to employees, advisors and consultants at exercise prices of no less than the fair value of the common stock on the grant date. If at the time of grant, the optionee owns stock representing more than 10% of the voting power of all classes of stock of the Company, the exercise price must be at least 110% of the fair value of the common stock on the grant date as determined by the board of directors. Non-statutory stock options may be granted to employees, advisors and consultants at exercise prices of less than the fair market value of a share of common stock on the date the non-statutory stock option is granted but shall under no circumstances be less than adequate consideration as determined by the board of directors for such a share. The vesting period of stock option grants is determined by the board of directors, ranging from zero to eight years. Stock options granted under the 2018 Plan expire in five or ten years from the date of grant. The Company reserved 425,000 shares of common stock for issuance, subject to certain adjustments, pursuant to awards under the 2018 Plan. Any shares of common stock related to awards outstanding under the 2011 Plan as of the effective date of the 2018 Plan, which thereafter terminate by expiration, forfeiture, cancellation or otherwise without the issuance of such shares, will be added to, and included in, the number of shares of common stock available for grant under the 2018 Plan. In addition, effective January 1, 2020 and continuing until the expiration of the 2018 Plan, the number of shares of common stock available for issuance under the 2018 Plan will automatically increase annually by 2% of the total number of issued and outstanding shares of the Company’s common stock as of December 31 st A summary of the Company’s stock option activity and related information is as follows: Stock Options Weighted- Average Exercise Price Weighted- Average Remaining Contractual Life (Years) Aggregate Intrinsic Value (000's) Balance as of January 1, 2018 420,956 $ 9.20 7.4 $ 5,021 Granted 30,000 13.10 Exercised (700 ) 7.10 Canceled (44,573 ) 7.10 Balance as of December 31, 2018 405,683 9.69 6.5 $ - Granted 203,936 5.02 Exercised - - Canceled (29,888 ) 9.86 Balance as of December 31, 2019 579,731 $ 8.04 7.0 $ 120 Exercisable as of December 31, 2019 375,479 $ 9.19 5.8 $ - The weighted-average grant date fair value of stock options granted to employees and directors for the years ended December 31, 2019 and 2018 was $3.35 and $14.87 per share, respectively. The aggregate grant date fair value of stock options that vested during the years ended December 31, 2019 and 2018 was $161,613 and $234,466, respectively. The intrinsic value of stock options vested and expected to vest and exercisable is calculated based on the difference between the exercise price and the fair value of the Company’s common stock as of December 31, 2019 and 2018. The intrinsic value of exercised stock options is the difference between the fair value of the underlying common stock and the exercise price as of the exercise date. As of December 31, 2019, and 2018, total unrecognized compensation cost related to stock options granted to employees was $627,129 and $435,639, respectively, which is expected to be recognized over a weighted-average period of 2.4 and 2.8 years, respectively. Determination of Fair Value The determination of the fair value of stock options on the date of grant using the Black-Scholes option-pricing model is affected by the estimated fair value of the Company’s common stock, as well as assumptions regarding a number of variables that are complex, subjective and generally require significant judgment to determine. The assumptions used to calculate the fair value of stock options were: Fair Value of Common Stock Prior to the IPO, the fair value of the common stock underlying the stock options was determined by the Company’s board of directors, with input from management and third-party valuations. Subsequent to the IPO, the fair value of the Company’s common stock was based on its publicly traded price per share. Expected Term The expected term represents the period that the Company’s stock option awards are expected to be outstanding. Stock options granted have a maximum contractual life of ten years. The Company estimates the expected term of the stock option to be six years based on historical data on employee exercises and post-vesting employment termination behavior. Expected Volatility As the Company does not have a trading history for its common stock, the expected stock price volatility for the Company’s common stock was estimated by taking the average historic price volatility for industry peers based on daily price observations over a period equivalent to the expected term of the stock option grants. Industry peers consist of several public companies in the Company’s industry which are of similar size, complexity and stage of development. The Company intends to continue to consistently apply this process using the same or similar public companies until a sufficient amount of historical information regarding the volatility of its own share price becomes available, or unless circumstances change such that the identified companies are no longer similar to the Company, in which case, more suitable companies whose share prices are publicly available would be used in the calculation. Risk-Free Interest Rate The risk-free interest rate is based on the U.S. Treasury rate, with maturities similar to the expected term of the stock options. Expected Dividend Yield The Company does not anticipate paying any dividends in the foreseeable future and, therefore, uses an expected dividend yield of zero. The grant date fair value of employee stock options was estimated using a Black-Scholes option-pricing model with the following weighted-average assumptions: Year Ended December 31, 2019 2018 Expected term (in years) 6.0 6.0 Expected volatility 75 % 75 % Risk-free interest rate 2.5 % 2.6 % Expected dividend yield - % - % Total stock-based compensation expense recognized in the consolidated statements of operations and comprehensive loss is as follows (in thousands): Year Ended December 31, 2019 2018 Research and development $ 100 $ 65 General and administrative 347 112 Total stock-based compensation expense $ 447 $ 177

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	1 2 . INCOME TAXES No provision for income taxes was recorded in the years ended December 31, 2019 and 2018. The Company remains in a cumulative loss position with a full valuation allowance recorded against its net deferred income tax assets as of December 31, 2019. The reconciliation of federal statutory income tax rate to the Company’s effective income tax rate is as follows: Year Ended December 31, 2019 2018 Expected income tax benefit at the federal statutory rate 21.0 % 21.0 % State taxes, net of federal benefit 5.1 5.2 Research and development credit, net 10.9 10.3 Non-deductible items and others 0.1 (0.4 ) Change in valuation allowance (37.1 ) (36.1 ) Total 0.0 % 0.0 % Deferred income taxes reflect the net effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. The principal components of the Company’s deferred tax assets consisted of the following as of December 31, 2019 and 2018 (in thousands): As of December 31, 2019 2018 Deferred tax assets: Federal and state net operating loss carryforwards $ 60,467 $ 52,362 Research and development tax credits 18,161 14,592 Depreciation and amortization 439 468 Reserves and accruals 168 56 Other 274 202 Total deferred tax assets 79,509 67,680 Less: valuation allowance (79,509 ) (67,680 ) Net deferred tax assets - - Deferred tax liability: Net deferred tax assets and liability $ - $ - The Company’s valuation allowance increased by $11.8 million and by $10.7 million for the years ended December 31, 2019 and 2018, respectively, in order to maintain a full valuation allowance against its deferred tax assets. Based on the Company’s history of losses, the Company recorded a full valuation allowance against its deferred tax assets as of December 31, 2019 and 2018. The Company intends to maintain a valuation allowance until sufficient positive evidence exists to support a reversal of the valuation allowance and the realization of the Company’s deferred tax assets. As of December 31, 2019, the Company had federal and state operating loss carryforwards of $229.2 million and $240.3 million, which begin to expire in the years ending December 31, 2024 and 2034, respectively. The Company had federal research and development tax credit carryforwards of $18.2 million as of December 31, 2019. This credit begins to expire from in the year ending December 31, 2021. Under the provisions of Sections 382 and 383 of the Internal Revenue Code (the IRC), net operating loss and credit carryforwards and other tax attributes may be subject to limitation if there has been a significant change in ownership of the Company, as defined by the IRC. Future owner or equity shifts, including an IPO, could result in limitations on net operating loss and credit carryforwards. The Company files income tax returns in the U.S. federal jurisdiction as well as many U.S. state jurisdictions. The tax years from January 1, 2016 to December 31, 2019 remain open to examination by the major jurisdictions in which the Company is subject to tax. Fiscal years outside the normal statute of limitations remain open to audit by tax authorities due to tax attributes generated in those early years, which have been carried forward and may be audited in subsequent years when utilized. The Company evaluates tax positions for recognition using a more-likely-than-not recognition threshold, and those tax positions eligible for recognition are measured as the largest amount of tax benefit that is greater than 50% likely of being realized upon the effective settlement with a taxing authority that has full knowledge of all relevant information. As of December 31, 2019, and 2018, the Company had no unrecognized income tax benefits that would affect the Company’s effective tax rate if recognized.

Net Loss Per Share Attributable

Net Loss Per Share Attributable to Common Stockholders	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Net Loss Per Share Attributable to Common Stockholders	1 3 . NET LOSS PER SHARE ATTRIBUTABLE TO COMMON STOCKHOLDERS The following weighted-average common stock equivalents were excluded from the calculation of diluted net loss per share for the periods presented as they had an anti-dilutive effect: Year ended December 31, 2019 2018 Options to purchase common stock 555,611 410,886 Contingently issuable common stock upon exchange of Vaccinex Products, LP units 1,197,479 1,202,566 Contingently issuable common stock upon exchange of VX3 units 1,318,797 1,158,009

Employee Benefit Plan

Employee Benefit Plan	12 Months Ended
	Dec. 31, 2019
Compensation And Retirement Disclosure [Abstract]
Employee Benefit Plan	1 4 . EMPLOYEE BENEFIT PLAN The Company sponsors a 401(k) plan that stipulates that eligible employees can elect to contribute to the 401(k) plan, subject to certain limitations, up to the lesser of the statutory maximum or 100% of eligible compensation on a pre-tax basis. Through December 31, 2019 and 2018, the Company has not elected to match employee contributions as permitted by the plan. The Company pays the administrative costs for the plan.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2019
Related Party Transactions [Abstract]
Related Party Transactions	1 5 . RELATED PARTY TRANSACTIONS As discussed in Note 9, the Company also leases its facility from 1895 Management, Ltd., a New York corporation controlled by an entity affiliated with the Company’s chairman and major stockholder of the Company. Rent expense incurred under this operating lease was $168,000 for each of the years ended December 31, 2019 and 2018. As discussed in Note 7, in November 2017, the Company entered into a research collaboration and license option agreement with Surface to identify and select antibodies against two target antigens, using the Company’s proprietary technology as described in the agreement. J. Jeffrey Goater, a member of the Company’s board of directors, served as the Chief Business Officer of Surface at that time, and currently serves as the Chief Executive Officer and a director of Surface. On July 26, 2019, the Company entered into a stock purchase agreement (the “Stock Purchase Agreement”) with certain investors including FCMI Parent, the Company’s majority stockholder, and Vaccinex (Rochester), L.L.C. FCMI Parent is majority owned and controlled by the Company’s chairman of the board and the Company’s president and chief executive officer, Dr. Maurice Zauderer, who is also the president and majority owner of Vaccinex, (Rochester), L.L.C. Pursuant to the Stock Purchase Agreement, the Company issued and sold to the investors 3,382,332 shares of its common stock at a purchase price of $4.08 per Share. The aggregate gross proceeds for the sale of the shares were $13.8 million. In connection with the Stock Purchase Agreement, on July 30, 2019, the Company entered into a registration rights agreement (the “Registration Rights Agreement”) with the investors that were party to the Stock Purchase Agreement, including FCMI Parent and Vaccinex (Rochester), L.L.C. that affords the investors certain registration rights with respect to the shares of the Company’s common stock purchased pursuant to the Stock Purchase Agreement. Pursuant to the Registration Rights Agreement, the Company filed a registration statement on Form S-3 (File No. 333-233607), declared effective on October 8, 2019, registering the shares acquired by the investors in the private placement.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2019
Subsequent Events [Abstract]
Subsequent Events	16. SUBSEQUENT EVENT On January 21, 2020, the Company entered into a stock purchase agreement (the “January 2020 Stock Purchase Agreement”) with certain investors as indicated on Exhibit A to the January 2020 Stock Purchase Agreement (the “Investors”), pursuant to which the Company agreed to issue and sell to the Investors, and the Investors agreed to purchase from the Company, an aggregate of 1,468,563 shares (the “Shares”) of Company Stock, at a purchase price of $5.09 per Share (the average closing price for the common stock for the five trading days immediately preceding the date of the January 2020 Stock Purchase Agreement). The January 2020 Stock Purchase Agreement contains customary representations and warranties of the parties. The closing of the private placement occurred on January 23, 2020. The aggregate gross proceeds for the sale of the Shares were $7.5 million. The Company intends to use the net proceeds from the private placement to fund the ongoing development of pepinemab and for working capital and general corporate purposes. On January 23, 2020, the Company entered into a registration rights agreement (the “January 2020 Registration Rights Agreement”) with the Investors that affords the Investors certain registration rights with respect to the Shares. On February 13, 2020, pursuant to the January 2020 Registration Rights Agreement, the Company filed with the SEC a registration statement covering the resale of the Shares. The Company has agreed to use commercially reasonable efforts to cause such registration statement to become effective on or prior to May 23, 2020. In addition, the Company agreed to use commercially reasonable efforts to keep the registration statement effective until the Shares have been sold thereunder or until the Shares can be sold without restriction. If the Company fails to meet the specified deadline for the effectiveness of the registration statement, the Company will be required to pay liquidated damages to the Investors, subject to maximum aggregate liquidated damages of 8.0% of the aggregate purchase price paid for the Shares. Interest on any unpaid liquidated damages will accrue at a rate of 1.0% per month. In addition, the Company agreed to provide Investors with certain “piggy-back” registration rights that may require the Company to effect certain registrations to register the Shares for resale in the event that no registration statement registering the Shares is effective and the Company is otherwise filing a registration statement under the Securities Act of 1933, as amended. The Registration Rights Agreement also contains certain indemnification and contribution provisions under which the Company and the Investors have agreed to indemnify each other against certain liabilities.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Basis of Presentation and Consolidation	Basis of Presentation and Consolidation These consolidated financial statements reflect the accounts and operations of the Company and those of its subsidiaries in which the Company has a controlling financial interest. As of December 31, 2019, and 2018, the Company’s accounts include Vaccinex Products and VX3 (DE) LP, a Delaware limited partnership (VX3). VX3 was established in October 2017 by a group of Canadian investors and was determined to be a variable interest entity (“VIE”) in which the Company is the primary beneficiary. The Company consolidates any VIE of which it is the primary beneficiary. The Company presents its noncontrolling interests as a separate component of stockholders’ equity (deficit). The company presents the net loss of VX3 equal to the percentage ownership interest retained in such entity by the respective noncontrolling party (VX3), and as a separate component within its consolidated statements of operations and comprehensive loss. The financial position of Vaccinex Products was not material as of December 31, 2019 and 2018, and there were no gains or losses for Vaccinex Products for the years ended December 31, 2019 and 2018. Intercompany transactions and balances have been eliminated.
Use of Estimates	Use of Estimates These consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”). The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities as of the date of the consolidated financial statements and the reported amount of expenses during the reporting period. Such management estimates include those relating to assumptions used in the valuation of stock option awards, the valuation of derivative instruments, and valuation allowances against deferred income tax assets. Actual results could differ from those estimates.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments with an original maturity of three months or less at the date of purchase to be cash equivalents. The Company deposits its cash primarily in checking and money market accounts.
Concentration of Credit Risk, Other Risks and Uncertainties	Concentration of Credit Risk, Other Risks and Uncertainties Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash and cash equivalents. Cash equivalents are deposited in interest-bearing money market accounts. Although the Company deposits its cash with multiple financial institutions, cash balances may occasionally be in excess of the amounts insured by the Federal Deposit Insurance Corporation. Management believes the financial risk associated with these balances is minimal and has not experienced any losses to date. The Company depends on third-party manufacturers for the manufacture of drug substance and drug product for clinical trials. The Company also relies on certain third parties for its supply chain. Disputes with these third- party manufacturers or shortages in goods or services from third-party suppliers could delay the manufacturing of the Company’s product candidates and adversely impact its results of operations.
Marketable Securities	Marketable Securities Marketable securities consist of investments with original maturities greater than 90 days at their acquisition date. The Company classifies all of its marketable securities as available-for-sale securities. The Company’s marketable securities are measured and reported at fair value using quoted prices in active markets for similar securities. Unrealized gains and losses on available-for-sale securities are reported as accumulated other comprehensive loss. The cost of securities sold is determined on a specific identification basis, and realized gains and losses are included in other income (expense), net in the consolidated statements of operations and comprehensive loss. The Company evaluates its marketable securities with unrealized losses for other-than-temporary impairment. When assessing marketable securities for other-than-temporary declines in value, the Company considers such factors as, among other things, how significant the decline in value is as a percentage of the original cost, how long the market value of the investment has been less than its original cost, the Company’s ability and intent to retain the investment for a period of time sufficient to allow for any anticipated recovery in fair value and market conditions in general. If any adjustment to fair value reflects a decline in the value of the investment that the Company considers to be “other-than-temporary,” the Company reduces the investment to fair value through a charge to the statement of operations and comprehensive loss. No such adjustments were necessary during the periods presented.
Fair Value of Financial Instruments	Fair Value of Financial Instruments Financial instruments consist of cash and cash equivalents, marketable securities, prepaid expenses and other current assets, accounts payable, accrued expenses, convertible promissory notes, and derivative liabilities. Cash equivalents and marketable securities are stated at fair value. Prepaid expenses and other current assets, accounts payable and accrued expenses are stated at their carrying value, which approximates fair value due to the short time to the expected receipt or payment date. The principal amount of the Company’s convertible promissory notes approximates fair value as the stated interest rate approximates market rates currently available to the Company. The derivative liabilities are stated were stated at fair value prior to their extinguishment in 2018.
Property and Equipment, Net	Property and Equipment, Net Property and equipment are recorded at cost. Depreciation is computed over estimated useful lives of the related assets using the straight-line method. Leasehold improvements are amortized on a straight-line basis over the shorter of the useful life or term of the lease. Upon retirement or disposal, the cost and related accumulated depreciation are removed from the consolidated balance sheets and the resulting gain or loss is recorded to general and administrative expense in the consolidated statements of operations. Routine expenditures for maintenance and repairs are expensed as incurred. Estimated useful lives for property and equipment are as follows: Property and Equipment Estimated Useful Life Research equipment 5 years Furniture and fixtures 5 years Computer equipment 3 years Leasehold improvements Lesser of estimated useful life or remaining lease term
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company reviews the recoverability of its long-lived assets when events or changes in circumstances occur that indicate that the carrying value of the asset may not be recoverable. The assessment of possible impairment is based on the ability to recover the carrying value of the assets from the expected future cash flows (undiscounted and without interest expense) of the related operations. If these cash flows are less than the carrying value of such assets, an impairment loss for the difference between the estimated fair value and carrying value is recorded. There was no impairment loss recognized during the years ended December 31, 2019 and 2018.
Derivative Liabilities	Derivative Liabilities The Company had outstanding derivative instruments related to certain features embedded within the Company’s outstanding convertible promissory notes, and an outstanding derivative instrument related to an arrangement providing a holder of one of the Company’s convertible promissory notes an option to purchase shares of equity in a future qualifying financing event. These derivatives were accounted for as derivative liabilities and remeasured to fair value as of each balance sheet date and the related remeasurement adjustments are recognized in the consolidated statements of operations. The Company recorded adjustments to the fair value of the derivative liabilities until the repayment of the related convertible promissory notes as discussed further in Note 8.
Treasury Stock	Treasury Stock The Company records treasury stock activities under the cost method whereby the cost of the acquired stock is recorded as treasury stock. The Company’s accounting policy upon the formal retirement of treasury stock is to deduct the par value from common stock and to reflect any excess of cost over par value as a reduction to additional paid-in capital (to the extent created by previous issuances of the shares) and then retained earnings. There was no treasury stock repurchased for the years ended December 31, 2019 and 2018.
Revenue Recognition	Revenue Recognition The Company’s revenues are generated primarily through collaborative research, license, development and commercialization agreements. We recognize revenue when our customers obtain control of promised goods or services, in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of ASC 606, the entity performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. At contract inception, once the contract is determined to be within the scope of ASC 606, the Company assesses the goods or services promised within each contract and determines those that are performance obligations and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied. Arrangements that include rights to additional goods or services that are exercisable at a customer’s discretion are generally considered options. We assess if these options provide a material right to the customer and if so, they are considered performance obligations. The exercise of a material right is accounted for as a contract modification for accounting purposes. The Company recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) each performance obligation is satisfied at a point in time or over time, and if over time this is based on the use of an output or input method. Amounts received prior to revenue recognition are recorded as deferred revenue. Amounts expected to be recognized as revenue within the 12 months following the balance sheet date are classified as current portion of deferred revenue in the accompanying consolidated balance sheets. Amounts not expected to be recognized as revenue within the 12 months following the balance sheet date are classified as deferred revenue, net of current portion. Amounts recognized as revenue, but not yet received or invoiced are generally recognized as contract assets in the Other Assets line item in the Consolidated Balance Sheets. Collaborative Arrangements – The Company has entered into collaboration agreements, which are within the scope of ASC 606, to discover, develop, manufacture and commercialize product candidates. The terms of these agreements typically contain multiple promises or obligations, which may include: (1) licenses, or options to obtain licenses, to use the Company’s research program materials, and (2) research and development activities to be performed on behalf of the collaboration partner. Payments the Company receives under these arrangements typically include one or more of the following: non-refundable, upfront license fees; option exercise fees; funding of research and/or development efforts; clinical and development, regulatory, and sales milestone payments; and royalties on future product sales. The Company analyzes its collaboration arrangements to assess whether they are within the scope of ASC 808, Collaborative Arrangements For a complete discussion of accounting for collaboration revenues, see Note 7, “Collaboration and license agreements”.
Research and Development Costs	Research and Development Costs Expenditures, including payroll, contractor expenses and supplies, for research and development of products are expensed as incurred. Clinical trial and other development costs incurred by third parties are expensed as the contracted work is performed. Where contingent milestone payments are due to third parties under research and development arrangements, the milestone payment obligations are expensed when the milestone results are probable of being achieved.
Stock-Based Compensation	Stock-Based Compensation The Company utilizes the Black-Scholes stock option-pricing model as the method for estimating the grant date fair value of its stock option awards. The Black-Scholes stock option-pricing model requires the use of highly subjective and complex assumptions, including the stock options’ expected term and the price volatility of the underlying stock. The grant date fair value of the portion of the stock option award that is ultimately expected to vest is recognized as compensation expense over the stock option awards’ requisite service periods. The Company recognizes stock-based compensation to expense using the straight-line method over the requisite service period. If there are any modifications or cancelations of stock option awards, the Company may be required to accelerate, increase or decrease any remaining unrecognized stock-based compensation expense.
Income Taxes	Income Taxes The Company uses the asset and liability method of accounting for income taxes. Deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to temporary differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities, which relate primarily to the carrying amount of the Company’s property and equipment and its net operating loss carryforward, are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. Deferred tax expense or benefit is the result of changes in the deferred tax assets and liabilities. Valuation allowances are established when necessary to reduce deferred tax assets where, based upon the available evidence, management concludes that it is more likely than not that the deferred tax assets will not be realized. In evaluating its ability to recover deferred tax assets, the Company considers all available positive and negative evidence, including its operating results, ongoing tax planning and forecasts of future taxable income on a jurisdiction-by-jurisdiction basis. Because of the uncertainty of the realization of the deferred tax assets, the Company has recorded a full valuation allowance against its deferred tax assets. Reserves are provided for tax benefits for which realization is uncertain. Such benefits are only recognized when the underlying tax position is considered more likely than not to be sustained on examination by a taxing authority, assuming they possess full knowledge of the position and facts. Interest and penalties related to uncertain tax positions are recognized in the provision for income taxes; however, the Company currently has no interest or penalties related to income taxes.
Segment and Geographic Information	Segment and Geographic Information The Company’s chief operating decision maker, its Chief Executive Officer, reviews its operating results on an aggregate basis for purposes of allocating resources and evaluating financial performance. The Company has one business activity, the discovery and development of targeted biotherapeutics to treat serious diseases and conditions with unmet medical needs, and there are no segment managers who are held accountable for operations or operating results. Accordingly, the Company operates in one segment. As of December 31, 2019, and 2018, all long-lived assets are located in the United States.
Net Loss Per Share Attributable to Vaccinex, Inc. Common Stockholders	Net Loss Per Share Attributable to Vaccinex, Inc. Common Stockholders The Company calculates its basic and diluted net loss per share attributable to Vaccinex, Inc. common stockholders in conformity with the two-class method required for companies with participating securities. The Company considers all series of its preferred stock to be participating securities. In the event a dividend is declared or paid on the Company’s common stock, holders of preferred stock are entitled to a proportionate share of such dividend in proportion to the holders of common stock on an as-if converted basis. Under the two-class method, basic net loss per share attributable to Vaccinex, Inc. common stockholders is calculated by dividing the net loss attributable to Vaccinex, Inc. common stockholders by the weighted-average number of shares of common stock outstanding for the period. Net loss attributable to Vaccinex, Inc. common stockholders is determined by allocating undistributed earnings between common and preferred stockholders. The diluted net loss per share attributable to Vaccinex, Inc. common stockholders is computed by giving effect to all potential dilutive common stock equivalents outstanding for the period determined using the treasury stock method. The net loss attributable to Vaccinex, Inc. common stockholders was not allocated to the preferred stock under the two-class method as the preferred stock do not have a contractual obligation to share in the Company’s losses. For purposes of this calculation, redeemable convertible preferred stock, convertible preferred stock, and stock options to purchase common stock are considered common stock equivalents but have been excluded from the calculation of diluted net loss per share attributable to Vaccinex, Inc. common stockholders as their effect is anti-dilutive.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Not Yet Adopted In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) Leases, Targeted Improvements to ASC 842, Leases , Leases The Company is currently evaluating the potential impact ASU 2016-02 may have on its financial position, results of operations, and related footnotes. The Company expects it will elect to utilize the available package of practical expedients permitted under the transition guidance within the new standard, which does not require the reassessment of the following: i) whether existing or expired arrangements are or contain a lease, ii) the lease classification of existing or expired leases, and iii) whether previous initial direct costs would qualify for capitalization under the new lease standard. Additionally, the Company expects it will make an accounting policy election to keep leases with an initial term of 12 months or less off of its balance sheet. The Company’s assessment will include, but is not limited to, evaluating the impact that this standard has on the lease of its corporate headquarters in Rochester, New York. Recently Adopted Accounting Pronouncements In May 2014, FASB issued ASU No. 2014-09, Revenue (ASC 606): Revenue from Contracts with Customers Revenue Recognition In November 2018, the FASB issued ASU No. 2018-18, Collaborative Arrangements (Topic 808)—Clarifying the Interaction between Topic 808 and ASC 606

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Summary of Estimated Useful Lives for Property and Equipment	Estimated useful lives for property and equipment are as follows: Property and Equipment Estimated Useful Life Research equipment 5 years Furniture and fixtures 5 years Computer equipment 3 years Leasehold improvements Lesser of estimated useful life or remaining lease term

Balance Sheet Components (Table

Balance Sheet Components (Tables)	12 Months Ended
	Dec. 31, 2019
Balance Sheet Related Disclosures [Abstract]
Property and Equipment	Property and equipment consist of the following (in thousands): As of December 31, 2019 As of December 31, 2018 Leasehold improvements $ 3,161 $ 3,145 Research equipment 3,442 3,219 Furniture and fixtures 350 350 Computer equipment 214 214 Property and equipment, gross 7,167 6,928 Less: accumulated depreciation and amortization (6,573 ) (6,324 ) Property and equipment, net $ 594 $ 604
Accrued Expenses	Accrued expenses consist of the following (in thousands): As of December 31, 2019 As of December 31, 2018 Accrued clinical trial cost $ 3,252 $ 3,796 Accrued payroll and related benefits 79 296 Accrued consulting and legal 262 236 Accrued other 77 36 Accrued expenses $ 3,670 $ 4,364

Marketable Securities (Tables)

Marketable Securities (Tables)	12 Months Ended
	Dec. 31, 2019
Investments Debt And Equity Securities [Abstract]
Summary of the Fair Value of Available-for-sale Marketable Securities	As of December 31, 2019, the Company did not hold any marketable securities. The fair value of available-for-sale marketable securities as of December 31, 2018, was as follows (in thousands): December 31, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Marketable securities: U.S. Treasury securities $ 14,106 $ - $ - $ 14,106 $ 14,106 $ - $ - $ 14,106

Fair Value of Financial Measu_2

Fair Value of Financial Measurements (Tables)	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Summary of Fair Value of Financial Assets by Level within Fair Value Hierarchy	The following table sets forth the fair value of the Company’s financial assets by level within the fair value hierarchy (in thousands): As of December 31, 2019 Fair Value Level 1 Level 2 Level 3 Financial Assets: Cash equivalents: Money market fund $ 1,464 $ 1,464 $ - $ - Total Financial Assets $ 1,464 $ 1,464 $ - $ - As of December 31, 2018 Fair Value Level 1 Level 2 Level 3 Financial Assets: Cash equivalents: Money market fund $ 4,881 $ 4,881 $ - $ - Marketable securities: U. S. Treasury securities $ 14,106 $ - $ 14,106 $ - Total Financial Assets $ 18,987 $ 4,881 $ 14,106 $ -

Common Stock Reserved For Iss_2

Common Stock Reserved For Issuance (Tables)	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Common Stock Reserved for Potential Future Issuances	Common stock has been reserved for the following potential future issuances: As of December 31, 2019 As of December 31, 2018 Shares underlying outstanding stock options 579,731 405,683 Shares available for future stock option grants 230,952 423,000 Exchange of Vaccinex Products, LP units 1,173,500 1,202,566 Conversion of VX3 units 1,318,797 1,318,797 Total shares of common stock reserved 3,302,980 3,350,046

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Stock Option Activity and Related Information	A summary of the Company’s stock option activity and related information is as follows: Stock Options Weighted- Average Exercise Price Weighted- Average Remaining Contractual Life (Years) Aggregate Intrinsic Value (000's) Balance as of January 1, 2018 420,956 $ 9.20 7.4 $ 5,021 Granted 30,000 13.10 Exercised (700 ) 7.10 Canceled (44,573 ) 7.10 Balance as of December 31, 2018 405,683 9.69 6.5 $ - Granted 203,936 5.02 Exercised - - Canceled (29,888 ) 9.86 Balance as of December 31, 2019 579,731 $ 8.04 7.0 $ 120 Exercisable as of December 31, 2019 375,479 $ 9.19 5.8 $ -
Grant Date Fair Value of Employee Stock Options Estimated Using Black-Scholes Option-Pricing Model with Weighted-Average Assumptions	The grant date fair value of employee stock options was estimated using a Black-Scholes option-pricing model with the following weighted-average assumptions: Year Ended December 31, 2019 2018 Expected term (in years) 6.0 6.0 Expected volatility 75 % 75 % Risk-free interest rate 2.5 % 2.6 % Expected dividend yield - % - %
Total Stock-Based Compensation Expense Recognized in Condensed Consolidated Statements of Operations and Comprehensive Loss	Total stock-based compensation expense recognized in the consolidated statements of operations and comprehensive loss is as follows (in thousands): Year Ended December 31, 2019 2018 Research and development $ 100 $ 65 General and administrative 347 112 Total stock-based compensation expense $ 447 $ 177

Income Tax (Tables)

Income Tax (Tables)	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Schedule of Effective Income Tax Rate Reconciliation	The reconciliation of federal statutory income tax rate to the Company’s effective income tax rate is as follows: Year Ended December 31, 2019 2018 Expected income tax benefit at the federal statutory rate 21.0 % 21.0 % State taxes, net of federal benefit 5.1 5.2 Research and development credit, net 10.9 10.3 Non-deductible items and others 0.1 (0.4 ) Change in valuation allowance (37.1 ) (36.1 ) Total 0.0 % 0.0 %
Schedule of Deferred Tax Assets and Liabilities	The principal components of the Company’s deferred tax assets consisted of the following as of December 31, 2019 and 2018 (in thousands): As of December 31, 2019 2018 Deferred tax assets: Federal and state net operating loss carryforwards $ 60,467 $ 52,362 Research and development tax credits 18,161 14,592 Depreciation and amortization 439 468 Reserves and accruals 168 56 Other 274 202 Total deferred tax assets 79,509 67,680 Less: valuation allowance (79,509 ) (67,680 ) Net deferred tax assets - - Deferred tax liability: Net deferred tax assets and liability $ - $ -

Net Loss Per Share Attributab_2

Net Loss Per Share Attributable to Common Stockholders (Tables)	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Weighted-Average Common Stock Equivalents Excluded from Calculation of Diluted Net Loss Per Share as They Had Anti-Dilutive Effect	The following weighted-average common stock equivalents were excluded from the calculation of diluted net loss per share for the periods presented as they had an anti-dilutive effect: Year ended December 31, 2019 2018 Options to purchase common stock 555,611 410,886 Contingently issuable common stock upon exchange of Vaccinex Products, LP units 1,197,479 1,202,566 Contingently issuable common stock upon exchange of VX3 units 1,318,797 1,158,009

Company and Nature of Business

Company and Nature of Business - Additional Information (Details) $ / shares in Units, $ in Thousands	Aug. 09, 2018USD ($)$ / sharesshares	Jan. 31, 2020USD ($)	Sep. 30, 2019USD ($)	Dec. 31, 2019USD ($)$ / sharesshares	Dec. 31, 2018USD ($)$ / sharesshares
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Cash flow from operations				$ (30,715)	$ (25,276)
Accumulated deficit				248,630	216,767
Proceeds from capital contribution					$ 12,000
Proceeds from private offering of common stock			$ 13,800	$ 13,800
Common stock, par value | $ / shares				$ 0.0001	$ 0.0001
Net proceeds from initial public offering					$ 37,125
Offering expenses					2,675
Repayment of convertible promissory note, related party					$ 5,500
Common Stock
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of shares issued and sold | shares				3,382,332
IPO
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Common stock, par value | $ / shares	$ 0.0001
Public offering price, per share | $ / shares	$ 12
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				3,333,334
Subsequent Event
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Proceeds from private offering of common stock		$ 7,500

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Details)	12 Months Ended
	Dec. 31, 2019USD ($)Segmentshares	Dec. 31, 2018USD ($)shares
Summary Of Significant Accounting Policies [Line Items]
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
Vaccinex Products
Summary Of Significant Accounting Policies [Line Items]
Gain or loss from VIE	$ 0	$ 0

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Summary of Estimated Useful Lives for Property and Equipment (Detail)	12 Months Ended
	Dec. 31, 2019
Property Plant And Equipment [Line Items]
Property, Plant and Equipment, Leasehold Improvements, Useful Life	Lesser of estimated useful life or remaining lease term
Research Equipment
Property Plant And Equipment [Line Items]
Property, Plant and Equipment, Useful Life	5 years
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property, Plant and Equipment, Useful Life	5 years
Computer Equipment
Property Plant And Equipment [Line Items]
Property, Plant and Equipment, Useful Life	3 years

Balance Sheet Components - Prop

Balance Sheet Components - Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 7,167	$ 6,928
Less: accumulated depreciation and amortization	(6,573)	(6,324)
Property and equipment, net	594	604
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	3,161	3,145
Research Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	3,442	3,219
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property and equipment, gross	350	350
Computer Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 214	$ 214

Balance Sheet Components - Addi

Balance Sheet Components - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Property Plant And Equipment [Abstract]
Depreciation and amortization expense	$ 249,000	$ 223,000

Balance Sheet Components - Sche

Balance Sheet Components - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Payables And Accruals [Abstract]
Accrued clinical trial cost	$ 3,252	$ 3,796
Accrued payroll and related benefits	79	296
Accrued consulting and legal	262	236
Accrued other	77	36
Accrued expenses	$ 3,670	$ 4,364

Marketable Securities - Additio

Marketable Securities - Additional Information (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Marketable Securities [Abstract]
Marketable securities	$ 0	$ 14,106,000

Marketable Securities - Summary

Marketable Securities - Summary of the Fair Value of Available-for-sale Marketable Securities (Details) $ in Thousands	Dec. 31, 2018USD ($)
Marketable Securities [Line Items]
Securities Available for Sale, Amortized Cost	$ 14,106
Securities Available for Sale, Gross Unrealized Gains	0
Securities Available for Sale, Gross Unrealized Losses	0
Securities Available for Sale, Fair Value	14,106
U.S. Treasury Securities
Marketable Securities [Line Items]
Securities Available for Sale, Amortized Cost	14,106
Securities Available for Sale, Gross Unrealized Gains	0
Securities Available for Sale, Gross Unrealized Losses	0
Securities Available for Sale, Fair Value	$ 14,106

Fair Value of Financial Measu_3

Fair Value of Financial Measurements - Summary of Fair Value of Financial Assets by Level within Fair Value Hierarchy (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Financial Assets:
Securities Available for Sale, Fair Value		$ 14,106
U.S. Treasury Securities
Financial Assets:
Securities Available for Sale, Fair Value		14,106
Fair Value Measurements Recurring
Financial Assets:
Total Financial Assets	$ 1,464	18,987
Fair Value Measurements Recurring | Level 1
Financial Assets:
Total Financial Assets	1,464	4,881
Fair Value Measurements Recurring | Level 2
Financial Assets:
Total Financial Assets		14,106
Fair Value Measurements Recurring | Money Market Funds
Financial Assets:
Cash equivalents, Fair value disclosure	1,464	4,881
Fair Value Measurements Recurring | Money Market Funds | Level 1
Financial Assets:
Cash equivalents, Fair value disclosure	$ 1,464	4,881
Fair Value Measurements Recurring | U.S. Treasury Securities
Financial Assets:
Securities Available for Sale, Fair Value		14,106
Fair Value Measurements Recurring | U.S. Treasury Securities | Level 2
Financial Assets:
Securities Available for Sale, Fair Value		$ 14,106

Fair Value of Financial Measu_4

Fair Value of Financial Measurements - Additional Information (Details) - Fair Value Measurements Recurring - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Financial assets, level 1 to level 2 transfers, amount	$ 0	$ 0
Financial assets, level 2 to level 1 transfers, amount	$ 0	$ 0

License and Services Agreement

License and Services Agreement - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended		12 Months Ended
	Mar. 31, 2018	Nov. 30, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
License And Services Agreement [Line Items]
Proceeds from capital contribution				$ 12,000
January 2017 Notes
License And Services Agreement [Line Items]
Repay an outstanding convertible note	$ 4,000
VX3
License And Services Agreement [Line Items]
Percentage of voting interest			90.00%	90.00%
Proceeds from capital contribution				$ 12,000
VX3 License Agreement
License And Services Agreement [Line Items]
Research and development, milestone payments to company		$ 32,000
Terms of license agreement upon termination			the Company will issue to VX3 or its designees the number of shares of the Company’s common stock equal to the lesser of (1) the aggregate of all payments made to VX3 by its partners divided by $18.20 and (2) the then fair market value of VX3 divided by the then fair market value of one share of the Company’s common stock.
Base amount to determine issuance of common stock upon termination		$ 18.20
Services Agreement
License And Services Agreement [Line Items]
Services payments received					$ 11,900

Collaboration Agreements - Addi

Collaboration Agreements - Additional Information (Details)	1 Months Ended	12 Months Ended
	Nov. 30, 2017USD ($)TargetAntigenMilestone	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue		$ 523,000	$ 724,000
Merck Sharp & Dohme Corp.
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Service revenue recognized			69,000
Surface Oncology, Inc.
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Service revenue recognized			229,166
Number of target antigens against which antibodies are to be identified and selected | TargetAntigen	2
Upfront payments fee received	$ 250,000	123,276	282,171	$ 250,000
Number of designated milestones | Milestone	4
Revenue		400,000
Surface Oncology, Inc. | Exclusive Product License Option
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue		300,000
Surface Oncology, Inc. | Exclusive Research Tool License
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue		$ 100,000
Surface Oncology, Inc. | Exercise of Product Option
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue			0
Surface Oncology, Inc. | Minimum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Term of research program	9 months
Surface Oncology, Inc. | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Term of research program	12 months
Heptares Therapeutics, Ltd.
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Service revenue recognized			$ 138,556

Convertible Promissory Notes -

Convertible Promissory Notes - Additional Information (Details) - USD ($)	1 Months Ended							12 Months Ended
	Mar. 31, 2018	Nov. 30, 2017	Oct. 31, 2017	Aug. 31, 2017	Apr. 30, 2017	Jan. 31, 2017	Jun. 30, 2016	Dec. 31, 2018
Debt Instrument [Line Items]
Annual interest rate			2.00%	2.00%	2.00%	0.00%
Debt instrument maturity term						3 years
Debt Instrument Face Amount						$ 10,000,000
Debt Instrument Carrying Amount			$ 6,000,000	$ 6,000,000	$ 6,000,000	4,000,000
Debt Instrument Periodic Payment Principal						6,000,000
Interest expense								$ 308,000
Loss on extinguishment of related party convertible promissory note								2,379,000
Embedded derivative, Derivative liability							$ 31,000
June 2016 Note
Debt Instrument [Line Items]
Annual interest rate							8.00%
Debt instrument maturity term							3 years
Increase of interest rate							12.00%
Debt Instrument Face Amount							$ 1,500,000
June 2016 Note | Convertible Promissory Notes
Debt Instrument [Line Items]
Loss on extinguishment of related party convertible promissory note								199,000
January 2017 Notes
Debt Instrument [Line Items]
Repayments of convertible debt	$ 4,000,000
January 2017 Notes | Convertible Promissory Notes
Debt Instrument [Line Items]
Debt Instrument Carrying Amount			$ 4,000,000		2,000,000	$ 4,000,000
Repayments of convertible debt	$ 4,000,000	$ 4,000,000			$ 2,000,000
Derivative liabilities written off with conversion of repayment								300,000
Loss on extinguishment of related party convertible promissory note								$ 2,200,000

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Commitments And Contingencies [Line Items]
Royalty payments, percent of net sales	1.00%
Monthly rental payments	$ 14,000
Future minimum operating leases payment in 2020	140,000
Future minimum operating leases payment in 2021	0
Future minimum operating leases payment in 2022	0
Future minimum operating leases payment in 2023	0
Future minimum operating leases payment in 2024	0
Rent expense incurred under operating lease	168,000	$ 168,000
General and Administrative
Commitments And Contingencies [Line Items]
Rent expense incurred under operating lease	168,000	$ 168,000
Contract Termination
Commitments And Contingencies [Line Items]
Termination payment	$ 25,500,000

Common Stock Reserved For Iss_3

Common Stock Reserved For Issuance - Common Stock Reserved For Potential Future Issuances (Details) - shares	Dec. 31, 2019	Dec. 31, 2018
Class Of Stock [Line Items]
Total shares of common stock reserved	3,302,980	3,350,046
Shares Underlying Outstanding Stock Options
Class Of Stock [Line Items]
Total shares of common stock reserved	579,731	405,683
Shares Available For Future Stock Option Grants
Class Of Stock [Line Items]
Total shares of common stock reserved	230,952	423,000
Exchange of Vaccinex Products, LP Units
Class Of Stock [Line Items]
Total shares of common stock reserved	1,173,500	1,202,566
Conversion of VX3 Units
Class Of Stock [Line Items]
Total shares of common stock reserved	1,318,797	1,318,797

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total shares of common stock reserved	3,302,980	3,350,046
Weighted-average grant date fair value of stock options granted to employees	$ 3.35	$ 14.87
Options granted	203,936	30,000
Aggregate grant date fair value of stock options vested	$ 161,613	$ 234,466
Intrinsic value of stock options exercised		11,000
Total unrecognized compensation cost related to stock options granted to employees	$ 627,129	$ 435,639
Maximum contractual life for options granted	10 years
Expected dividend yield	0.00%
2018 Omnibus Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total shares of common stock reserved	425,000
Percentage of total shares of common stock reserved	2.00%
2018 Omnibus Incentive Plan | Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of voting power of all classes of stock to be owned by optionee to determine the exercise price	10.00%
Exercise price as a percentage of fair value of common stock on grant date if optionee owns stock representing more than 10 percent of voting power of all classes of stock	110.00%
Employee Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total unrecognized compensation cost related to stock options granted to employees, weighted-average recognition period	2 years 4 months 24 days	2 years 9 months 18 days
Expected term of stock option	6 years	6 years
Employee Stock Options | 2011 Employee Equity Plan | Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options granted, expiration year	5 years
Employee Stock Options | 2011 Employee Equity Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options granted, expiration year	10 years
Employee Stock Options | 2018 Omnibus Incentive Plan | Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options granted, expiration year	5 years
Employee Stock Options | 2018 Omnibus Incentive Plan | Minimum | Board of Directors
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period of stock option grants	0 years
Employee Stock Options | 2018 Omnibus Incentive Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options granted, expiration year	10 years
Employee Stock Options | 2018 Omnibus Incentive Plan | Maximum | Board of Directors
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period of stock option grants	8 years

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock Option Activity and Related Information (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Options, Balance	405,683	420,956
Stock Options, Granted	203,936	30,000
Stock Options, Exercised		(700)
Stock Options, Cancelled	(29,888)	(44,573)
Stock Options, Balance	579,731	405,683	420,956
Stock Options, Exercisable	375,479
Weighted-Average Exercise Price, Balance	$ 9.69	$ 9.20
Weighted-Average Exercise Price, Granted	5.02	13.10
Weighted-Average Exercise Price, Exercised		7.10
Weighted-Average Exercise Price, Canceled	9.86	7.10
Weighted-Average Exercise Price, Balance	8.04	$ 9.69	$ 9.20
Weighted-Average Exercise Price, Exercisable	$ 9.19
Weighted-Average Remaining Contractual Life (Years), Balance	7 years	6 years 6 months	7 years 4 months 24 days
Weighted-Average Remaining Contractual Life (Years), Exercisable	5 years 9 months 18 days
Aggregate Intrinsic Value, Balance		$ 5,021
Aggregate Intrinsic Value, Balance	$ 120		$ 5,021

Stock-Based Compensation - Gran

Stock-Based Compensation - Grant Date Fair Value of Employee Stock Options Estimated Using Black-Scholes Option-Pricing Model with Weighted-Average Assumptions (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected dividend yield	0.00%
Employee Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term of stock option	6 years	6 years
Expected volatility	75.00%	75.00%
Risk-free interest rate	2.50%	2.60%

Stock-Based Compensation - Tota

Stock-Based Compensation - Total Stock-Based Compensation Expense Recognized in Condensed Consolidated Statements of Operations and Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	$ 447	$ 177
Research and Development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	100	65
General and Administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	$ 347	$ 112

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating Loss Carryforwards [Line Items]
Provision for income taxes	$ 0	$ 0	$ 0
Increase (decrease) in valuation allowance for deferred tax asset	$ 11,800,000	10,700,000
Tax credit carryforwards, expiration date	Dec. 31, 2021
Unrecognized tax benefits that would impact effective tax rate	$ 0	$ 0
Description of tax years open to examination by major jurisdictions	from January 1, 2016 to December 31, 2019
Federal
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 229,200,000
Operating loss carryforwards, expiration date	Dec. 31, 2024
Federal | Research
Operating Loss Carryforwards [Line Items]
Tax credit carryforwards	$ 18,200,000
State
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 240,300,000
Operating loss carryforwards, expiration date	Dec. 31, 2034

Income Taxes - Schedule of Effe

Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Expected income tax benefit at the federal statutory rate	21.00%	21.00%
State taxes, net of federal benefit	5.10%	5.20%
Research and development credit, net	10.90%	10.30%
Non-deductible items and others	0.10%	(0.40%)
Change in valuation allowance	(37.10%)	(36.10%)
Total	0.00%	0.00%

Income Taxes - Schedule of Defe

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Federal and state net operating loss carryforwards	$ 60,467	$ 52,362
Research and development tax credits	18,161	14,592
Depreciation and amortization	439	468
Reserves and accruals	168	56
Other	274	202
Total deferred tax assets	79,509	67,680
Less: valuation allowance	(79,509)	(67,680)
Deferred tax liability:
Net deferred tax assets and liability	$ 0	$ 0

Net Loss Per Share Attributab_3

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	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
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	555,611	410,886
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	1,197,479	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	1,158,009

Employee Benefit Plan - Additio

Employee Benefit Plan - Additional Information (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Compensation And Retirement Disclosure [Abstract]
Maximum employee contribution to plan	100.00%	100.00%

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Details)	Jul. 26, 2019USD ($)$ / sharesshares	Nov. 30, 2017USD ($)TargetAntigen	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Related Party Transaction [Line Items]
Rent expense incurred under operating lease			$ 168,000	$ 168,000
Revenue			523,000	724,000
Stock Purchase Agreement
Related Party Transaction [Line Items]
Sale of stock, transaction date	Jul. 26, 2019
Private placement closing date	Jul. 30, 2019
Stock Purchase Agreement | Common Stock
Related Party Transaction [Line Items]
Aggregate number of shares issued | shares	3,382,332
Shares issued, price per share | $ / shares	$ 4.08
Aggregate gross proceeds from the sale of shares	$ 13,800,000
Surface Oncology, Inc.
Related Party Transaction [Line Items]
Number of target antigens against which antibodies are to be identified and selected | TargetAntigen		2
Service fee payment received		$ 250,000	123,276	$ 282,171	$ 250,000
Revenue			400,000
Surface Oncology, Inc. | Exclusive Product License Option
Related Party Transaction [Line Items]
Revenue			300,000
Surface Oncology, Inc. | Exclusive Research Tool License
Related Party Transaction [Line Items]
Revenue			$ 100,000

Subsequent Events - Additional

Subsequent Events - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	Jan. 23, 2020	Jan. 21, 2020	Jul. 26, 2019
Stock Purchase Agreement
Subsequent Event [Line Items]
Sale of stock, transaction date			Jul. 26, 2019
Common Stock | Stock Purchase Agreement
Subsequent Event [Line Items]
Aggregate number of shares issued			3,382,332
Shares issued, price per share			$ 4.08
Aggregate gross proceeds from the sale of shares			$ 13.8
Subsequent Event | Registration Rights Agreement
Subsequent Event [Line Items]
Interest on unpaid liquidated damages	1.00%
Subsequent Event | Registration Rights Agreement | Maximum
Subsequent Event [Line Items]
Percentage of failure to pay liquidated damage	8.00%
Subsequent Event | Stock Purchase Agreement
Subsequent Event [Line Items]
Sale of stock, transaction date		Jan. 21, 2020
Subsequent Event | Common Stock | Stock Purchase Agreement
Subsequent Event [Line Items]
Aggregate number of shares issued		1,468,563
Shares issued, price per share		$ 5.09
Aggregate gross proceeds from the sale of shares		$ 7.5