Document And Entity Information - shares	6 Months Ended
Document And Entity Information - shares	Jun. 30, 2019	Aug. 14, 2019
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Entity Current Reporting Status	Yes
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 Small Business	true
Entity Emerging Growth Company	true
Entity Shell Company	false
Entity Ex Transition Period	false
Entity Common Stock, Shares Outstanding		14,862,536
Entity File Number	001-38624
Entity Tax Identification Number	161603202
Entity Address, Address Line One	1895 Mount Hope Avenue
Entity Address, City or Town	Rochester
Entity Address, State or Province	New York
Entity Address, Postal Zip Code	14620
City Area Code	585
Local Phone Number	271-2700

Condensed Consolidated Balance Sheets (Unaudited) - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 5,279,000	$ 5,618,000
Marketable securities	0	14,106,000
Accounts receivable, net	871,000	639,000
Prepaid expenses and other current assets	416,000	1,061,000
Total current assets	6,566,000	21,424,000
Property and equipment, net	555,000	604,000
TOTAL ASSETS	7,121,000	22,028,000
Current liabilities:
Accounts payable	5,448,000	2,322,000
Accrued expenses	4,053,000	4,364,000
TOTAL LIABILITIES	9,501,000	6,686,000
Commitments and contingencies (Note 9)
Stockholders’ equity:
Common stock, par value of $0.0001 per share; 100,000,000 shares authorized as of June 30, 2019 and December 31, 2018; 11,481,056 and 11,476,601 shares issued as of June 30, 2019 and December 31, 2018; 11,480,204 and 11,475,749 shares outstanding as of June 30, 2019 and December 31, 2018	1,000	1,000
Additional paid-in capital	208,329,000	208,156,000
Treasury stock, at cost; 852 shares of common stock as of June 30, 2019 and December 31, 2018	(11,000)	(11,000)
Accumulated deficit	(234,662,000)	(216,767,000)
Total Vaccinex, Inc. stockholders’ deficit	(26,343,000)	(8,621,000)
Noncontrolling interests	23,963,000	23,963,000
TOTAL STOCKHOLDERS’ (DEFICIT) EQUITY	(2,380,000)	15,342,000
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 7,121,000	$ 22,028,000

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Jun. 30, 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	11,481,056	11,476,601
Common stock, shares outstanding	11,480,204	11,475,749
Treasury stock, common shares	852	852

Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Statement [Abstract]
Revenue	$ 25,000	$ 126,000	$ 119,000	$ 332,000
Costs and expenses:
Cost of revenue	16,000	246,000	191,000	486,000
Research and development	7,304,000	5,512,000	14,716,000	9,966,000
General and administrative	1,563,000	925,000	3,210,000	2,146,000
Total costs and expenses	8,883,000	6,683,000	18,117,000	12,598,000
Loss from operations	(8,858,000)	(6,557,000)	(17,998,000)	(12,266,000)
Change in fair value of derivative liabilities		30,000		338,000
Interest expense		(81,000)		(348,000)
Loss on extinguishment of related party convertible promissory note				(2,180,000)
Other income (expense), net	30,000		103,000	(14,000)
Loss before provision for income taxes	(8,828,000)	(6,608,000)	(17,895,000)	(14,470,000)
Provision for income taxes	0	0	0	0
Net loss	(8,828,000)	(6,608,000)	(17,895,000)	(14,470,000)
Net loss attributable to noncontrolling interests	0	0	0	0
Net loss attributable to Vaccinex, Inc.	(8,828,000)	(6,608,000)	(17,895,000)	(14,470,000)
Cumulative dividends on redeemable preferred stock		(800,000)		(1,592,000)
Net loss attributable to Vaccinex, Inc. common stockholders, basic and diluted	$ (8,828,000)	$ (7,408,000)	$ (17,895,000)	$ (16,062,000)
Net loss per share attributable to Vaccinex, Inc. common stockholders, basic and diluted	$ (0.77)	$ (6.72)	$ (1.56)	$ (14.56)
Weighted-average shares used in computing net loss per share attributable to Vaccinex, Inc. common stockholders, basic and diluted	11,479,294	1,103,144	11,477,521	1,102,853

Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) (Unaudited) - USD ($) $ in Thousands	Total	Redeemable Convertible Preferred Stock	Convertible Preferred Stock	Common Stock	Additional Paid-in Capital	Treasury Stock	Treasury Stock Redeemable Convertible Preferred Stock	Accumulated Deficit	Total Vaccinex,Inc. Stockholders' Deficit	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
Stock-based compensation	36				36				36
Capital contribution	8,000									8,000
Net loss	(7,862)							(7,862)	(7,862)
Balance at Mar. 31, 2018	(113,316)		$ 7,684		54,159	$ (11)		(195,111)	(133,279)	19,963
Balance, Shares at Mar. 31, 2018		53,089,959
Balance at Mar. 31, 2018		$ 111,718
Balance, Shares at Mar. 31, 2018			5,702,450	1,103,396		836	163
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
Net loss	(14,470)
Balance at Jun. 30, 2018	(115,867)		$ 7,684		54,216	$ (11)		(201,719)	(139,830)	23,963
Balance, Shares at Jun. 30, 2018		53,089,959
Balance at Jun. 30, 2018		$ 111,718
Balance, Shares at Jun. 30, 2018			5,702,450	1,104,096		836	163
Balance at Mar. 31, 2018	(113,316)		$ 7,684		54,159	$ (11)		(195,111)	(133,279)	19,963
Balance, Shares at Mar. 31, 2018		53,089,959
Balance at Mar. 31, 2018		$ 111,718
Balance, Shares at Mar. 31, 2018			5,702,450	1,103,396		836	163
Stock-based compensation	52				52				52
Capital contribution	4,000									4,000
Exercise of stock options	5				5				5
Exercise of stock options, Shares				700
Net loss	(6,608)							(6,608)	(6,608)
Balance at Jun. 30, 2018	(115,867)		$ 7,684		54,216	$ (11)		(201,719)	(139,830)	23,963
Balance, Shares at Jun. 30, 2018		53,089,959
Balance at Jun. 30, 2018		$ 111,718
Balance, Shares at Jun. 30, 2018			5,702,450	1,104,096		836	163
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
Stock-based compensation	60				60				60
Net loss	(9,067)							(9,067)	(9,067)
Balance at Mar. 31, 2019	6,335			$ 1	208,216	$ (11)		(225,834)	(17,628)	23,963
Balance, Shares at Mar. 31, 2019				11,476,601		852
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
Net loss	(17,895)
Balance at Jun. 30, 2019	(2,380)			$ 1	208,329	$ (11)		(234,662)	(26,343)	23,963
Balance, Shares at Jun. 30, 2019				11,481,056		852
Balance at Mar. 31, 2019	6,335			$ 1	208,216	$ (11)		(225,834)	(17,628)	23,963
Balance, Shares at Mar. 31, 2019				11,476,601		852
Conversion of Vaccinex Products LP Units into common shares, Shares				4,455
Stock-based compensation	113				113				113
Net loss	(8,828)							(8,828)	(8,828)
Balance at Jun. 30, 2019	$ (2,380)			$ 1	$ 208,329	$ (11)		$ (234,662)	$ (26,343)	$ 23,963
Balance, Shares at Jun. 30, 2019				11,481,056		852

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (17,895)	$ (14,470)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	117	112
Amortization of debt discount		284
Net amortization of premiums and discounts on marketable securities	(45)
Stock-based compensation	173	88
Change in fair value of derivative liabilities		(338)
Loss on extinguishment of related party convertible promissory note		2,180
Changes in operating assets and liabilities:
Accounts receivable	(232)	(235)
Prepaid expenses and other current assets	645	(160)
Accounts payable	3,126	1,014
Accrued expenses	(311)	1,220
Deferred revenue		(194)
Net cash used in operating activities	(14,422)	(10,499)
CASH FLOWS FROM INVESTING ACTIVITIES:
Sales and maturities of marketable securities	14,150
Purchase of property and equipment	(67)	(61)
Net cash provided by (used in) investing activities	14,083	(61)
CASH FLOWS FROM FINANCING ACTIVITIES:
Payments of initial public offering costs		(327)
Repayment of convertible promissory note, related party		(4,000)
Proceeds from capital contribution		12,000
Proceeds from exercise of stock options		5
Net cash provided by financing activities		7,678
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	(339)	(2,882)
CASH AND CASH EQUIVALENTS–Beginning of period	5,618	4,180
CASH AND CASH EQUIVALENTS–End of period	$ 5,279
SUPPLEMENTAL DISCLOSURES OF NONCASH INVESTING AND FINANCING ACTIVITIES:
Deferred offering costs in accounts payable and accrued expenses		$ 1,360

Company and Nature of Business

6 Months Ended

Jun. 30, 2019

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Company and Nature of Business

1.	COMPANY AND NATURE OF BUSINESS

Description 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, manufacturing and clinical development.

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 unaudited condensed 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 $14.4 million and $25.3 million for the six months ended June 30, 2019 and year ended December 31, 2018, respectively, and an accumulated deficit of $234.7 million and $216.8 million as of June 30, 2019 and December 31, 2018, respectively. The Company’s ability to continue as a going concern is at issue due to its historical net losses and negative cash flows from operations, and its need for additional financing to fund future operations. These conditions raise substantial doubt about the Company’s ability to continue as a going concern. 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. In addition, the Company received $12.0 million in capital contributions from noncontrolling interests during each of the years ended December 31, 2018 and 2017. As 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 our projected operating requirements and our existing cash and cash equivalents and marketable securities, we plan to complete an additional financing transaction prior to the commencement of the 2020 second quarter 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.

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 effected; 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 Accounting Policies

6 Months Ended

Jun. 30, 2019

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2.	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Basis of Presentation and Consolidation

These condensed 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. All intercompany transactions and balances have been eliminated.

The accompanying condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America ("U.S. GAAP") and following the requirements of the Securities and Exchange Commission ("SEC"), for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by U.S. GAAP can be condensed or omitted. These condensed consolidated financial statements have been prepared on the same basis as the Company’s annual consolidated financial statements and, in the opinion of management, reflect all adjustments, consisting only of normal recurring adjustments that are necessary for a fair statement of the Company’s financial information. The results of operations for the interim periods presented are not necessarily indicative of the results to be expected for any subsequent quarter or for the entire year ending December 31, 2019. The year-end balance sheet data was derived from audited consolidated financial statements but does not include all disclosures required by U.S. GAAP. Certain information and note disclosures normally included in annual consolidated financial statements prepared in accordance with U.S. GAAP have been omitted under the rules and regulations of the SEC.

These condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and related notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018, filed with the SEC on March 13, 2019.

Use of Estimates

These condensed consolidated financial statements have been prepared in conformity with 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 condensed 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.

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 and marketable securities. Cash equivalents are deposited in interest-bearing money market accounts and short-term investments consist of highly liquid U.S. government treasury bills and notes. The Company deposits its cash with multiple financial institutions and 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.

Comprehensive Loss

The Company did not have any other comprehensive income or loss for any of the periods presented and therefore comprehensive loss did not differ from net loss.

Recent Accounting Pronouncements Not Yet Adopted

In February 2016, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standard Update (“ASU”) No. 2016-02, Leases, which supersedes the Accounting Standards Codification (“ASC”) No. 840, Leases. ASU No. 2016-02 requires lessees to recognize all leases, with exception of short-term leases, as lease liabilities on the balance sheet. Under ASU No. 2016-02, a lease is defined as a lessee’s obligation to make lease payments arising from a lease, measured on a discounted basis, and a right-of-use asset, which is an asset that represents the lessee’s right to use, or control the use of, a specified asset during the lease term. ASU No. 2016-02 also requires additional disclosure about the amount, timing and uncertainty of cash flow from leases. The new standard is effective for the Company at the earlier of losing the emerging growth company status or the Company’s fiscal year beginning January 1, 2020. Early adoption is permitted. This new standard will require the present value of these leases to be recorded in the condensed consolidated balance sheets as a right-of-use asset and lease liability. The Company will adopt the new standard effective January 1, 2020 and is continuing to evaluate the impact of this guidance on its condensed consolidated financial statements and related disclosures.

Recently Adopted Accounting Pronouncements

In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers, which supersedes the revenue recognition requirements in ASC No. 605, Revenue Recognition. ASU No. 2014-09 is based on the principle that revenue is recognized to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU No. 2014-09 also requires additional disclosure about the nature, amount, timing and uncertainty of revenues and cash flows arising from customer contracts, including significant judgments and changes in judgments and assets recognized from costs incurred to obtain or fulfill a contract. In August 2015, the FASB issued ASU No. 2015-14 to defer the effective date by one year with early adoption permitted as of the original effective date. In addition, the FASB issued ASU Nos. 2016-08, 2016-10 and 2016-12 in March 2016, April 2016 and May 2016, respectively, to help provide interpretive clarification on the new guidance in ASC No. 606. ASU Nos. 2016-08, 2016-10 and 2016-12 are all effective beginning the same period as ASU No. 2014-09. The Company adopted the new revenue standards using the modified retrospective method as of January 1, 2019; however, it is not required to reflect the effects of adoption in its consolidated financial statements until it files its annual report for the fiscal year ending December 31, 2019. The Company is in the process of evaluating the effect that the new revenue standards will have on its consolidated financial statements and related disclosures.

Balance Sheet Components

6 Months Ended

Jun. 30, 2019

Balance Sheet Related Disclosures [Abstract]

Balance Sheet Components

3.	BALANCE SHEET COMPONENTS

Property and Equipment

Property and equipment consist of the following (in thousands):

	As of June 30, 2019			As of December 31, 2018
Leasehold improvements	$	3,145		$	3,145
Research equipment		3,286			3,219
Furniture and fixtures		350			350
Computer equipment		214			214
Property and equipment, gross		6,995			6,928
Less: accumulated depreciation and amortization		(6,440	)		(6,324	)
Property and equipment, net	$	555		$	604

Depreciation and amortization expense related to property and equipment was $57,000 and $56,000 for the three months ended June 30, 2019 and 2018, respectively, and $117,000 and $112,000 for the six months ended June 30, 2019 and 2018, respectively.

Accrued Expenses

Accrued expenses consist of the following (in thousands):

	As of June 30, 2019		As of December 31, 2018
Accrued clinical trial cost	$	3,612	$	3,796
Accrued payroll and related benefits		265		236
Accrued consulting and legal		102		296
Accrued other		74		36
Accrued expenses	$	4,053	$	4,364

Marketable Securities

6 Months Ended

Jun. 30, 2019

Investments Debt And Equity Securities [Abstract]

Marketable Securities

4.	MARKETABLE SECURITIES

As of June 30, 2019, the Company did not hold any marketable securities. The fair value of available-for-sale marketable securities as of December 31, 2018, is as follows (in thousands):

	As of 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 Measurements

6 Months Ended

Jun. 30, 2019

Fair Value Disclosures [Abstract]

Fair Value of Financial Measurements

5.	FAIR VALUE OF FINANCIAL MEASUREMENTS

Assets and liabilities recorded at fair value on a recurring basis in the condensed 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 hierarchy based on the following three levels of inputs, of which the first two are considered observable and the last unobservable, that may be used to measure 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 June 30, 2019
	Fair Value		Level 1		Level 2		Level 3
Financial Assets:
Cash equivalents:
Money market funds	$	3,108	$	3,108	$	-	$	-
Total Financial Assets	$	3,108	$	3,108	$	-	$	-

	As of December 31, 2018
	Fair Value		Level 1		Level 2		Level 3
Financial Assets:
Cash equivalents:
Money market funds	$	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 either of the six months ended June 30, 2019 and 2018, other than the monetizing of the U.S. treasury securities during the six month period ended June 30, 2019.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

License and Services Agreement

6 Months Ended

Jun. 30, 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 VX15, our most advanced product candidate. In June 2018, the U.S. Adopted Name Council approved the use of pepinemab as the adopted name for VX15. 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 the Canadian investors 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 at each of June 30, 2019 and December 31, 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 condensed 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 ending 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 were amended; therefore, the above assessment resulting in the Company being the primary beneficiary of the VX3 entity remained unchanged as of June 30, 2019.

For the six months ended June 30, 2018, the Company recorded the gross proceeds of $12.0 million, received from VX3 as capital contributions from noncontrolling interests on the condensed consolidated financial statements.

Collaboration Agreements

6 Months Ended

Jun. 30, 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 six months ended June 30, 2018. The research agreement expired 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 agreement was 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 has been granted 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 the antibody targeting the first antigen and (ii) an exclusive research tool license to use the antibody targeting the second antigen to perform research.

Under the agreement, Surface will pay an upfront technology access fee of $250,000 and 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 will make payments to the Company based on time incurred by the Company in the conduct of the work plan described in the agreement. Surface will 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 $63,000 and $125,000 was recognized as revenue from the amortization of this upfront fee for the three and six months ended June 30, 2018. The Company also received $25,000 and $64,000 service fee payments for work conducted under the agreement for the three months ended June 30, 2019 and 2018, respectively and $118,877 and $133,000 for the six months ended June 30, 2019 and 2018, respectively. This agreement will expire upon the expiration of both research programs and all evaluation and testing periods.

Convertible Promissory Notes

6 Months Ended

Jun. 30, 2019

Debt Disclosure [Abstract]

Convertible Promissory Notes

8.	CONVERTIBLE PROMISSORY NOTES

As of June 30, 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 accrued interest at a compounded annual rate of 8% and had a maturity date three years from issuance, if not converted before then. Upon the occurrence of a default event, such as payment or performance defaults, bankruptcy, change in control (if elected to be treated as such by the lenders), or other violation, the interest rate would increase to a compounded annual rate of 12% until such time the default is cured. Upon maturity, the holder of these convertible promissory notes was to be repaid the outstanding principal plus all accrued interest. The Company also had the ability to prepay the convertible promissory notes, plus accrued interest, without penalty. The debt issuance costs for these convertible promissory notes were not material. The June 2016 Note was paid in full on August 17, 2018. See “Repayment of Convertible Promissory Notes” below.

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 $49,000 and $284,000 for the amortization of the debt discounts during the three and six months ended June 30, 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 condensed consolidated statement of operations for the six months ended June 30, 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 were written off and the $199,000 unamortized debt discount was recognized as a loss on extinguishment of related party convertible promissory note in the condensed consolidated statements of operations in the three months ended September 30, 2018.

Commitments and Contingencies

6 Months Ended

Jun. 30, 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 a 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 June 30, 2019, the future minimum payments for the operating lease are $224,000.

Rent expense incurred under the operating lease was $42,000 and $84,000 for each of the three and six months ended June 30, 2019 and 2018, respectively.

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 June 30, 2019, and December 31, 2018, the Company was not involved in any material legal proceedings.

Common Stock Reserved For Issuance

6 Months Ended

Jun. 30, 2019

Equity [Abstract]

Common Stock Reserved For Issuance

10.	COMMON STOCK RESERVED FOR ISSUANCE

Common stock has been reserved for the following potential future issuances:

	As of June 30, 2019		As of December 31, 2018
Shares underlying outstanding stock options		588,737		405,683
Shares available for future stock option grants		239,946		423,000
Exchange of Vaccinex Products, LP units		1,198,111		1,202,566
Conversion of VX3 units		1,318,797		1,318,797
Total shares of common stock reserved		3,345,591		3,350,046

During the three months ended June 30, 2019 4,455 units of Vaccinex Products, LP were converted to common shares of Vaccinex, Inc. at par value of $.0001 per share.

Stock-Based Compensation

6 Months Ended

Jun. 30, 2019

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-Based Compensation

11.	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. 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 our common stock as of December 31^st of the immediately preceding year or such lesser number as our board of directors may decide, which may be zero.

A summary of the Company’s stock option activity and related information is as follows:

	Options Outstanding
	Stock Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Life (Years)		Aggregate Intrinsic Value (000's)
Balance as of December 31, 2018		405,683		$	9.69		6.5	$	-
Granted		188,550			4.96
Exercised		-			-
Canceled		(5,496	)		13.01
Balance as of June 30, 2019		588,737		$	8.15		7.2	$	211
Exercisable as of June 30, 2019		376,922		$	9.36		5.9	$	1

The weighted-average grant date fair value of stock options granted to employees for the six months ended June 30, 2019 and 2018 was $3.31 and $15.63 per share, respectively. The aggregate grant date fair value of stock options that vested during the three months ended June 30, 2019 and 2018 was $78,156 and $143,000, 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 June 30, 2019 and December 31, 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 June 30, 2019, and December 31, 2018, total unrecognized compensation cost related to stock options granted to employees was $861,569 and $435,639, respectively, which is expected to be recognized over a weighted-average period of 2.6 and 2.8 years, respectively.

The grant date fair value of employee stock options was estimated using a Black-Scholes option-pricing model with the following weighted-average assumptions:

	Six Months Ended June 30,
	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 condensed consolidated statements of operations is as follows (in thousands):

	Three Months Ended June 30,				Six Months Ended June 30,
	2019		2018		2019		2018
Research and development	$	31	$	19	$	46	$	34
General and administrative		82		33		127		54
Total stock-based compensation expense	$	113	$	52	$	173	$	88

Net Loss Per Share Attributable to Common Stockholders

6 Months Ended

Jun. 30, 2019

Earnings Per Share [Abstract]

Net Loss Per Share Attributable to Common Stockholders

13.	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:

	Three Months Ended June 30,				Six Months Ended June 30,
	2019		2018		2019		2018
Preferred stock (if converted)		-		7,039,155		-		7,039,155
Options to purchase common stock		546,068		410,292		489,059		417,569
Contingently issuable common stock upon exchange of Vaccinex Products, LP units		1,199,021		1,202,566		1,200,794		1,202,566
Contingently issuable common stock upon exchange of VX3 units		1,318,797		1,176,288		1,318,797		994,558

Subsequent Event

6 Months Ended

Jun. 30, 2019

Subsequent Events [Abstract]

Subsequent Event

17.	SUBSEQUENT EVENT

On July 26, 2019, the Company entered into a stock purchase agreement (the “Stock Purchase Agreement”) with certain investors as indicated on Exhibit A to the 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 3,382,332 shares (the “Shares”) of Company Stock, at a purchase price of $4.08 per Share (the average closing price for the common stock for the five trading days immediately preceding the date of the Stock Purchase Agreement). The Stock Purchase Agreement contains customary representations and warranties of the parties. The closing of the private placement occurred on July 30, 2019.

The aggregate gross proceeds for the sale of the Shares were $13,799,915. 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.

FCMI Parent Co., one of the Investors, is the Company’s majority stockholder and is controlled by Albert D. Friedberg, the Company’s chairman. Vaccinex (Rochester), L.L.C., of which Dr. Maurice Zauderer, the Company’s president and chief executive officer, is the president and a majority owner, is another Investor. Dr. Zauderer exercises voting and investment power over the shares held by Vaccinex (Rochester) L.L.C. Both before and after the private placement, FCMI Parent Co. and Vaccinex (Rochester), L.L.C. owned approximately 55% and 7%, respectively, of the Company’s outstanding common stock. The Stock Purchase Agreement and the transactions contemplated thereby were approved by the unanimous consent of the board of directors of the Company.

The Shares have not been registered under the Securities Act of 1933, as amended (the “1933 Act”), and were issued and sold in a private placement pursuant to Section 4(a)(2) of the 1933 Act and Rule 506 of Regulation D as promulgated by the Securities and Exchange Commission (the “SEC”) under the 1933 Act. Each of the Investors represented that it is an “accredited investor” within the meaning of Rule 501 of Regulation D, and it acquired the securities for investment only and not with a view towards, or for resale in connection with, the public sale or distribution thereof. The Shares were offered without any general solicitation by the Company or its representatives.

Also, on July 26, 2019, the Company entered into a registration rights agreement (the “Registration Rights Agreement”) with the Investors that affords the Investors certain registration rights with respect to the Shares. Under the Registration Rights Agreement, the Company has agreed, among other things, to use its reasonable best efforts to file with the SEC a registration statement covering the resale of the Shares within 60 days from the closing of the transactions and cause such registration statement to become effective on or prior to 90 calendar days (or, in the event of a substantive review by the SEC, 135 calendar days) from the closing date. 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 deadlines 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% 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 1933 Act.

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 Accounting Policies (Policies)	6 Months Ended
Summary of Significant Accounting Policies (Policies)	Jun. 30, 2019
Accounting Policies [Abstract]
Basis of Presentation and Consolidation	Basis of Presentation and Consolidation These condensed 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. All intercompany transactions and balances have been eliminated. The accompanying condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America ("U.S. GAAP") and following the requirements of the Securities and Exchange Commission ("SEC"), for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by U.S. GAAP can be condensed or omitted. These condensed consolidated financial statements have been prepared on the same basis as the Company’s annual consolidated financial statements and, in the opinion of management, reflect all adjustments, consisting only of normal recurring adjustments that are necessary for a fair statement of the Company’s financial information. The results of operations for the interim periods presented are not necessarily indicative of the results to be expected for any subsequent quarter or for the entire year ending December 31, 2019. The year-end balance sheet data was derived from audited consolidated financial statements but does not include all disclosures required by U.S. GAAP. Certain information and note disclosures normally included in annual consolidated financial statements prepared in accordance with U.S. GAAP have been omitted under the rules and regulations of the SEC. These condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and related notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018, filed with the SEC on March 13, 2019.
Use of Estimates	Use of Estimates These condensed consolidated financial statements have been prepared in conformity with 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 condensed 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.
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 and marketable securities. Cash equivalents are deposited in interest-bearing money market accounts and short-term investments consist of highly liquid U.S. government treasury bills and notes. The Company deposits its cash with multiple financial institutions and 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.
Comprehensive Loss	Comprehensive Loss The Company did not have any other comprehensive income or loss for any of the periods presented and therefore comprehensive loss did not differ from net loss.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Not Yet Adopted In February 2016, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standard Update (“ASU”) No. 2016-02, Leases, which supersedes the Accounting Standards Codification (“ASC”) No. 840, Leases. ASU No. 2016-02 requires lessees to recognize all leases, with exception of short-term leases, as lease liabilities on the balance sheet. Under ASU No. 2016-02, a lease is defined as a lessee’s obligation to make lease payments arising from a lease, measured on a discounted basis, and a right-of-use asset, which is an asset that represents the lessee’s right to use, or control the use of, a specified asset during the lease term. ASU No. 2016-02 also requires additional disclosure about the amount, timing and uncertainty of cash flow from leases. The new standard is effective for the Company at the earlier of losing the emerging growth company status or the Company’s fiscal year beginning January 1, 2020. Early adoption is permitted. This new standard will require the present value of these leases to be recorded in the condensed consolidated balance sheets as a right-of-use asset and lease liability. The Company will adopt the new standard effective January 1, 2020 and is continuing to evaluate the impact of this guidance on its condensed consolidated financial statements and related disclosures. Recently Adopted Accounting Pronouncements In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers, which supersedes the revenue recognition requirements in ASC No. 605, Revenue Recognition. ASU No. 2014-09 is based on the principle that revenue is recognized to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU No. 2014-09 also requires additional disclosure about the nature, amount, timing and uncertainty of revenues and cash flows arising from customer contracts, including significant judgments and changes in judgments and assets recognized from costs incurred to obtain or fulfill a contract. In August 2015, the FASB issued ASU No. 2015-14 to defer the effective date by one year with early adoption permitted as of the original effective date. In addition, the FASB issued ASU Nos. 2016-08, 2016-10 and 2016-12 in March 2016, April 2016 and May 2016, respectively, to help provide interpretive clarification on the new guidance in ASC No. 606. ASU Nos. 2016-08, 2016-10 and 2016-12 are all effective beginning the same period as ASU No. 2014-09. The Company adopted the new revenue standards using the modified retrospective method as of January 1, 2019; however, it is not required to reflect the effects of adoption in its consolidated financial statements until it files its annual report for the fiscal year ending December 31, 2019. The Company is in the process of evaluating the effect that the new revenue standards will have on its consolidated financial statements and related disclosures.

Balance Sheet Components (Tables)

6 Months Ended

Jun. 30, 2019

Balance Sheet Related Disclosures [Abstract]

Property and Equipment

Property and equipment consist of the following (in thousands):

	As of June 30, 2019			As of December 31, 2018
Leasehold improvements	$	3,145		$	3,145
Research equipment		3,286			3,219
Furniture and fixtures		350			350
Computer equipment		214			214
Property and equipment, gross		6,995			6,928
Less: accumulated depreciation and amortization		(6,440	)		(6,324	)
Property and equipment, net	$	555		$	604

Accrued Expenses

Accrued expenses consist of the following (in thousands):

	As of June 30, 2019		As of December 31, 2018
Accrued clinical trial cost	$	3,612	$	3,796
Accrued payroll and related benefits		265		236
Accrued consulting and legal		102		296
Accrued other		74		36
Accrued expenses	$	4,053	$	4,364

Marketable Securities (Tables)

6 Months Ended

Jun. 30, 2019

Investments Debt And Equity Securities [Abstract]

Summary of the Fair Value of Available-for-sale Marketable Securities

As of June 30, 2019, the Company did not hold any marketable securities. The fair value of available-for-sale marketable securities as of December 31, 2018, is as follows (in thousands):

	As of 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 Measurements (Tables)

6 Months Ended

Jun. 30, 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 June 30, 2019
	Fair Value		Level 1		Level 2		Level 3
Financial Assets:
Cash equivalents:
Money market funds	$	3,108	$	3,108	$	-	$	-
Total Financial Assets	$	3,108	$	3,108	$	-	$	-

	As of December 31, 2018
	Fair Value		Level 1		Level 2		Level 3
Financial Assets:
Cash equivalents:
Money market funds	$	4,881	$	4,881	$	-	$	-
Marketable securities:
U. S. Treasury securities		14,106		-		14,106		-
Total Financial Assets	$	18,987	$	4,881	$	14,106	$	-

- Definition

Tabular disclosure of financial instruments measured at fair value, including those classified in shareholders' equity measured on a recurring or nonrecurring basis. Disclosures include, but are not limited to, fair value measurements recorded and the reasons for the measurements, level within the fair value hierarchy in which the fair value measurements are categorized and transfers between levels 1 and 2. Nonrecurring fair value measurements are those that are required or permitted in the statement of financial position in particular circumstances.

+ References + Details

Common Stock Reserved For Issuance (Tables)

6 Months Ended

Jun. 30, 2019

Equity [Abstract]

Common Stock Reserved for Potential Future Issuances

Common stock has been reserved for the following potential future issuances:

	As of June 30, 2019		As of December 31, 2018
Shares underlying outstanding stock options		588,737		405,683
Shares available for future stock option grants		239,946		423,000
Exchange of Vaccinex Products, LP units		1,198,111		1,202,566
Conversion of VX3 units		1,318,797		1,318,797
Total shares of common stock reserved		3,345,591		3,350,046

Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 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:

	Options Outstanding
	Stock Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Life (Years)		Aggregate Intrinsic Value (000's)
Balance as of December 31, 2018		405,683		$	9.69		6.5	$	-
Granted		188,550			4.96
Exercised		-			-
Canceled		(5,496	)		13.01
Balance as of June 30, 2019		588,737		$	8.15		7.2	$	211
Exercisable as of June 30, 2019		376,922		$	9.36		5.9	$	1

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:

	Six Months Ended June 30,
	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

Total stock-based compensation expense recognized in the condensed consolidated statements of operations is as follows (in thousands):

	Three Months Ended June 30,				Six Months Ended June 30,
	2019		2018		2019		2018
Research and development	$	31	$	19	$	46	$	34
General and administrative		82		33		127		54
Total stock-based compensation expense	$	113	$	52	$	173	$	88

Net Loss Per Share Attributable to Common Stockholders (Tables)

6 Months Ended

Jun. 30, 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:

	Three Months Ended June 30,				Six Months Ended June 30,
	2019		2018		2019		2018
Preferred stock (if converted)		-		7,039,155		-		7,039,155
Options to purchase common stock		546,068		410,292		489,059		417,569
Contingently issuable common stock upon exchange of Vaccinex Products, LP units		1,199,021		1,202,566		1,200,794		1,202,566
Contingently issuable common stock upon exchange of VX3 units		1,318,797		1,176,288		1,318,797		994,558

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

Balance Sheet Components - Property and Equipment (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 6,995	$ 6,928
Less: accumulated depreciation and amortization	(6,440)	(6,324)
Property and equipment, net	555	604
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	3,145	3,145
Research Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	3,286	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 - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Payables And Accruals [Abstract]
Accrued clinical trial cost	$ 3,612	$ 3,796
Accrued payroll and related benefits	265	236
Accrued consulting and legal	102	296
Accrued other	74	36
Accrued expenses	$ 4,053	$ 4,364

Marketable Securities - Summary of the Fair Value of Available-for-sale Marketable Securities (Details) $ in Thousands	Dec. 31, 2018 USD ($)
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 Measurements - Summary of Fair Value of Financial Assets by Level within Fair Value Hierarchy (Details) - USD ($) $ in Thousands	Jun. 30, 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	$ 3,108	18,987
Fair Value Measurements Recurring \| Money Market Funds
Financial Assets:
Cash equivalents, Fair value disclosure	3,108	4,881
Fair Value Measurements Recurring \| U.S. Treasury Securities
Financial Assets:
Securities Available for Sale, Fair Value		14,106
Fair Value Measurements Recurring \| Level 1
Financial Assets:
Total Financial Assets	3,108	4,881
Fair Value Measurements Recurring \| Level 1 \| Money Market Funds
Financial Assets:
Cash equivalents, Fair value disclosure	$ 3,108	4,881
Fair Value Measurements Recurring \| Level 2
Financial Assets:
Total Financial Assets		14,106
Fair Value Measurements Recurring \| Level 2 \| U.S. Treasury Securities
Financial Assets:
Securities Available for Sale, Fair Value		$ 14,106

License and Services Agreement - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended		6 Months Ended		12 Months Ended
	Mar. 31, 2018	Nov. 30, 2017	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
License And Services Agreement [Line Items]
Proceeds from capital contribution				$ 12,000	$ 12,000	$ 12,000
January 2017 Notes
License And Services Agreement [Line Items]
Repay an outstanding convertible note	$ 4,000
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 the Canadian investors 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
VX3
License And Services Agreement [Line Items]
Percentage of voting interest			90.00%		90.00%
Proceeds from capital contribution				$ 12,000

Collaboration Agreements - Additional Information (Details)	1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Nov. 30, 2017 USD ($) TargetAntigen Milestone	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)
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			$ 63,000		125,000
Number of target antigens against which antibodies are to be identified and selected \| TargetAntigen	2
Upfront fee to be received	$ 250,000
Number of designated milestones \| Milestone	4
Upfront payments fee received		$ 25,000	$ 64,000	$ 118,877	$ 133,000	$ 250,000
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

Convertible Promissory Notes - Additional Information (Details) - USD ($)	1 Months Ended							3 Months Ended		6 Months Ended
	Mar. 31, 2018	Nov. 30, 2017	Oct. 31, 2017	Aug. 31, 2017	Apr. 30, 2017	Jan. 31, 2017	Jun. 30, 2016	Sep. 30, 2018	Jun. 30, 2018	Jun. 30, 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									$ 49,000,000	$ 284,000,000
Loss on extinguishment of related party convertible promissory note										2,180,000
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 - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Commitments And Contingencies [Line Items]
Royalty payments, percent of net sales			1.00%
Monthly rental payments	$ 14,000		$ 14,000
Future minimum operating leases	224,000		224,000
Rent expense incurred under operating lease	$ 42,000	$ 42,000	84,000	$ 84,000
Contract Termination
Commitments And Contingencies [Line Items]
Termination payment			$ 25,500

Common Stock Reserved For Issuance - Additional Information (Details) - $ / shares	3 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Class Of Stock [Line Items]
Common stock, par value	$ 0.0001	$ 0.0001
Common Stock
Class Of Stock [Line Items]
Conversion of units to common shares	4,455
Vaccinex Products, LP Units \| Common Stock
Class Of Stock [Line Items]
Conversion of units to common shares	4,455

Stock-Based Compensation - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total shares of common stock reserved	3,345,591		3,345,591		3,350,046
Weighted-average grant date fair value of stock options granted to employees			$ 3.31	$ 15.63
Options granted			188,550
Aggregate grant date fair value of stock options vested	$ 78,156	$ 143,000
Total unrecognized compensation cost related to stock options granted to employees	$ 861,569		$ 861,569		$ 435,639
2018 Omnibus Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total shares of common stock reserved	425,000		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 7 months 6 days		2 years 9 months 18 days
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 \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options granted, expiration year			10 years

Stock-Based Compensation - Summary of Stock Option Activity and Related Information (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Options Outstanding, Options, Balance	405,683
Options Outstanding, Options, Granted	188,550
Options Outstanding, Options, Cancelled	(5,496)
Options Outstanding, Options, Balance	588,737	405,683
Options Outstanding, Options, Exercisable	376,922
Options Outstanding, Weighted-Average Exercise Price, Balance	$ 9.69
Options Outstanding, Weighted-Average Exercise Price, Granted	4.96
Options Outstanding, Weighted-Average Exercise Price, Canceled	13.01
Options Outstanding, Weighted-Average Exercise Price, Balance	8.15	$ 9.69
Options Outstanding, Weighted-Average Exercise Price, Exercisable	$ 9.36
Options Outstanding Weighted-Average Remaining Contractual Life (Years), Balance	7 years 2 months 12 days	6 years 6 months
Options Outstanding Weighted-Average Remaining Contractual Life (Years), Exercisable	5 years 10 months 24 days
Options Outstanding, Aggregate Intrinsic Value, Balance	$ 211
Options Outstanding, Aggregate Intrinsic Value, Exercisable	$ 1

Stock-Based Compensation - Grant Date Fair Value of Employee Stock Options Estimated Using Black-Scholes Option-Pricing Model with Weighted-Average Assumptions (Details) - Employee Stock Options	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
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 - Total Stock-Based Compensation Expense Recognized in Condensed Consolidated Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	$ 113	$ 52	$ 173	$ 88
Research and Development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	31	19	46	34
General and Administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	$ 82	$ 33	$ 127	$ 54

Net Loss Per Share Attributable to Common Stockholders - Weighted-Average Common Stock Equivalents Excluded from Calculation of Diluted Net Loss Per Share as They Had Anti-Dilutive Effect (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Convertible Preferred Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Weighted-average common stock equivalents excluded from calculation of diluted net loss per share		7,039,155		7,039,155
Employee Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Weighted-average common stock equivalents excluded from calculation of diluted net loss per share	546,068	410,292	489,059	417,569
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	1,199,021	1,202,566	1,200,794	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	1,176,288	1,318,797	994,558

Segment and Geographic Information - Additional Information (Details)	6 Months Ended	12 Months Ended
	Jun. 30, 2019 BusinessActivity SegmentManager Segment	Dec. 31, 2018 Segment
Segment Reporting Information [Line Items]
Number of business activity \| BusinessActivity	1
Number of segment managers held accountable for operations or operating results \| SegmentManager	0
United States
Segment Reporting Information [Line Items]
Number of operating segments \| Segment	1	1

Related Party Transactions - Additional Information (Details)	1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Nov. 30, 2017 TargetAntigen	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)
Related Party Transaction [Line Items]
Rent expense incurred under operating lease		$ 42,000	$ 42,000	$ 84,000	$ 84,000
Surface Oncology, Inc.
Related Party Transaction [Line Items]
Number of target antigens against which antibodies are to be identified and selected \| TargetAntigen	2
Upfront payments fee received		$ 25,000	$ 64,000	$ 118,877	$ 133,000	$ 250,000

Subsequent Event - Additional Information (Details) - USD ($)		6 Months Ended
	Jul. 26, 2019	Jun. 30, 2019
Stock Purchase Agreement
Subsequent Event [Line Items]
Sale of stock, transaction date	Jul. 26, 2019
Private placement closing date	Jul. 30, 2019
Sale of stock transaction description		On July 26, 2019, the Company entered into a stock purchase agreement (the “Stock Purchase Agreement”) with certain investors as indicated on Exhibit A to the 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 3,382,332 shares (the “Shares”) of Company Stock, at a purchase price of $4.08 per Share (the average closing price for the common stock for the five trading days immediately preceding the date of the Stock Purchase Agreement). The Stock Purchase Agreement contains customary representations and warranties of the parties. The closing of the private placement occurred on July 30, 2019.
Stock Purchase Agreement \| Common Stock \| Subsequent Event
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	$ 13,799,915
Stock Purchase Agreement \| Common Stock \| Subsequent Event \| FCMI Parent
Subsequent Event [Line Items]
Sale of stock ownership percentage	55.00%
Stock Purchase Agreement \| Common Stock \| Subsequent Event \| Vaccinex LLC
Subsequent Event [Line Items]
Sale of stock ownership percentage	7.00%
Registration Rights Agreement
Subsequent Event [Line Items]
Sale of stock, transaction date	Jul. 26, 2019
Sale of stock transaction description		on July 26, 2019, the Company entered into a registration rights agreement (the “Registration Rights Agreement”) with the Investors that affords the Investors certain registration rights with respect to the Shares. Under the Registration Rights Agreement, the Company has agreed, among other things, to use its reasonable best efforts to file with the SEC a registration statement covering the resale of the Shares within 60 days from the closing of the transactions and cause such registration statement to become effective on or prior to 90 calendar days (or, in the event of a substantive review by the SEC, 135 calendar days) from the closing date. 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 deadlines 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% 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 1933 Act.
Registration Rights Agreement \| Subsequent Event
Subsequent Event [Line Items]
Percentage of maximum aggregate liquidated damages of aggregate purchase price paid for shares	8.00%
Accrued interest rate on unpaid liquidated damages per month	1.00%

Fair Value of Financial Measurements - Additional Information (Details) - Fair Value Measurements Recurring	Jun. 30, 2018 USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Financial assets, level 1 to level 2 transfers, amount	$ 0
Financial assets, level 2 to level 1 transfers, amount	$ 0

Employee Benefit Plan - Additional Information (Details)	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Compensation And Retirement Disclosure [Abstract]
Maximum employee contribution to plan	100.00%	100.00%

Marketable Securities - Additional Information (Details) - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Marketable Securities [Abstract]
Marketable securities	$ 0	$ 14,106,000