Document And Entity Information - shares	9 Months Ended
Document And Entity Information - shares	Sep. 30, 2018	Nov. 13, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q3
Trading Symbol	0001205922
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 Ex Transition Period	false
Entity Common Stock, Shares Outstanding		11,475,749

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 11,258	$ 4,180
Marketable securities	16,121
Accounts receivable, net	403	117
Prepaid expenses and other current assets	1,555	677
Total current assets	29,337	4,974
Property and equipment, net	544	601
TOTAL ASSETS	29,881	5,575
Current liabilities:
Accounts payable	2,276	1,910
Accrued expenses	3,818	1,957
Deferred revenue	42	298
Total current liabilities	6,136	4,165
Convertible promissory notes to related party, net		2,813
Derivative liabilities		369
TOTAL LIABILITIES	6,136	7,347
Commitments and contingencies (Note 9)
Redeemable convertible preferred stock (Series B, B-1, B-2, C, D), par value of $0.001 per share; zero and 66,317,000 shares authorized as of September 30, 2018 and December 31, 2017; zero shares issued and outstanding as of September 30, 2018; 53,089,959 shares issued and 53,089,796 shares outstanding as of December 31, 2017 with aggregate liquidation preference of $0 and $140,261 as of September, 2018 and December 31, 2017		111,718
Stockholders’ equity (deficit):
Convertible preferred stock (Series A), par value of $0.001 per share; zero and 5,702,450 shares authorized, issued and outstanding as of September 30, 2018 and December 31, 2017 with aggregate liquidation preference of $0 and $7,684 as of September 30, 2018 and December 31, 2017		7,684
Common stock, par value of $0.0001 per share; 160,000,000 shares authorized as of September 30, 2018 and December 31, 2017; 11,476,601 and 1,103,396 shares issued as of September 30, 2018 and December 31, 2017; 11,475,749 and 1,102,560 shares outstanding as of September 30, 2018 and December 31, 2017	1
Additional paid-in capital	208,110	54,123
Treasury stock, at cost; zero and 163 shares of redeemable convertible preferred stock as of September 30, 2018 and December 31, 2017, and 852 and 836 shares of common stock as of September 30, 2018 and December 31, 2017	(11)	(11)
Accumulated deficit	(208,318)	(187,249)
Total Vaccinex, Inc. stockholders’ deficit	(218)	(125,453)
Noncontrolling interests	23,963	11,963
TOTAL STOCKHOLDERS’ EQUITY (DEFICIT)	23,745	(113,490)
TOTAL LIABILITIES, REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS’ EQUITY (DEFICIT)	$ 29,881	$ 5,575

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Temporary equity, par value	$ 0.001	$ 0.001
Temporary equity, shares authorized	0	66,317,000
Temporary equity, shares issued	0	53,089,959
Temporary equity, shares outstanding	0	53,089,796
Temporary equity, aggregate liquidation preference	$ 0	$ 140,261
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	160,000,000	160,000,000
Common stock, shares issued	11,476,601	1,103,396
Common stock, shares outstanding	11,475,749	1,102,560
Treasury stock, preferred shares	0	163
Treasury stock, common shares	852	836
Series A Convertible Preferred Stock
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	0	5,702,450
Preferred stock, shares issued	0	5,702,450
Preferred stock, shares outstanding	0	5,702,450
Preferred stock, aggregate liquidation preference	$ 0	$ 7,684

Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Revenue	$ 198,000		$ 530,000
Costs and expenses:
Cost of revenue	246,000		732,000
Research and development	5,314,000	$ 4,292,000	15,280,000	$ 11,523,000
General and administrative	1,092,000	1,040,000	3,238,000	3,384,000
Total costs and expenses	6,652,000	5,332,000	19,250,000	14,907,000
Loss from operations	(6,454,000)	(5,332,000)	(18,720,000)	(14,907,000)
Change in fair value of derivative liabilities	31,000	157,000	369,000	(214,000)
Interest expense	(44,000)	(361,000)	(392,000)	(988,000)
Loss on extinguishment of related party convertible promissory note	(199,000)		(2,379,000)
Other income (expense), net	67,000		53,000	(23,000)
Loss before provision for income taxes	(6,599,000)	(5,536,000)	(21,069,000)	(16,132,000)
Provision for income taxes	0	0	0	0
Net loss	(6,599,000)	(5,536,000)	(21,069,000)	(16,132,000)
Net loss attributable to Vaccinex, Inc.	(6,599,000)	(5,536,000)	(21,069,000)	(16,132,000)
Cumulative dividends on redeemable convertible preferred stock		(809,000)		(2,401,000)
Net loss attributable to Vaccinex, Inc. common stockholders, basic and diluted	$ (6,599,000)	$ (6,345,000)	$ (21,069,000)	$ (18,533,000)
Net loss per share attributable to Vaccinex, Inc. common stockholders, basic and diluted	$ (0.93)	$ (5.75)	$ (6.76)	$ (16.82)
Weighted-average shares used in computing net loss per share attributable to Vaccinex, Inc. common stockholders, basic and diluted	7,078,715	1,102,520	3,116,695	1,101,723

Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) (Unaudited) - USD ($) $ in Thousands	Total	IPO	Redeemable Convertible Preferred Stock	Convertible Preferred Stock	Common Stock	Common Stock IPO	Common Stock Series B Redeemable Convertible Preferred Stock	Common Stock Series A Convertible Preferred Stock	Additional Paid-in Capital	Additional Paid-in Capital IPO	Additional Paid-in Capital Series B Redeemable Convertible Preferred Stock	Additional Paid-in Capital Series A Convertible Preferred Stock	Treasury Stock	Treasury Stock Redeemable Convertible Preferred Stock	Accumulated Deficit	Total Vaccinex,Inc. Stockholders' Deficit	Total Vaccinex,Inc. Stockholders' Deficit IPO	Noncontrolling Interests
Balance at Dec. 31, 2016	$ (107,065)			$ 7,684					$ 53,789				$ (11)		$ (168,527)	$ (107,065)
Balance, Shares at Dec. 31, 2016			48,694,355
Balance at Dec. 31, 2016			$ 103,736
Balance, Shares at Dec. 31, 2016				5,702,450	1,101,359								836	163
Stock-based compensation	249								249							249
Issuance of Series D redeemable convertible preferred stock, net of issuance cost			$ 7,982
Issuance of Series D redeemable convertible preferred stock, net of issuance cost, Shares			4,395,604
Exercise of stock options	15								15							15
Exercise of stock options, Shares					2,037
Net loss	(16,132)														(16,132)	(16,132)
Balance at Sep. 30, 2017	(122,933)			$ 7,684					54,053				$ (11)		(184,659)	(122,933)
Balance, Shares at Sep. 30, 2017			53,089,959
Balance at Sep. 30, 2017			$ 111,718
Balance, Shares at Sep. 30, 2017				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		53,089,959
Balance at Dec. 31, 2017	$ 111,718		$ 111,718
Balance, Shares at Dec. 31, 2017				5,702,450	1,103,396								836	163
Initial public offering, net of issuance costs of $5,551		$ 34,450								$ 34,450							$ 34,450
Initial public offering, net of issuance costs of $5,551, 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
Stock-based compensation	131								131							131
Exercise of stock options	$ 5								5							5
Exercise of stock options, Shares	700				700
Net loss	$ (21,069)														(21,069)	(21,069)
Balance at Sep. 30, 2018	$ 23,745				$ 1				$ 208,110				$ (11)		$ (208,318)	$ (218)		$ 23,963
Balance, Shares at Sep. 30, 2018	0
Balance, Shares at Sep. 30, 2018					11,476,601								852

Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) (Unaudited) (Parenthetical) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Redeemable convertible preferred stock, issuance cost		$ 18
IPO
Initial public offering, issuance costs	$ 5,551

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($)	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (21,069,000)	$ (16,132,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	166,000	152,000
Amortization of debt discount	308,000	886,000
Net amortization of premiums and discounts on marketable securities	(29,000)
Stock-based compensation	131,000	249,000
Change in fair value of derivative liabilities	(369,000)	214,000
Loss on extinguishment of related party convertible promissory note	2,379,000
Changes in operating assets and liabilities:
Accounts receivable	(286,000)	(13,000)
Prepaid expenses and other current assets	(878,000)	(456,000)
Accounts payable	323,000	60,000
Accrued expenses	1,861,000	(169,000)
Deferred revenue	(256,000)	69,000
Net cash used in operating activities	(17,719,000)	(15,140,000)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of marketable securities	(16,092,000)
Purchase of property and equipment	(66,000)	(65,000)
Net cash used in investing activities	(16,158,000)	(65,000)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of convertible promissory notes to related parties, net of issuance cost		5,976,000
Proceeds from initial public offering of common stock, net of commissions and underwriting discounts	37,125,000
Payments of initial public offering costs	(2,675,000)
Proceeds from exercise of stock options	5,000	15,000
Repayment of convertible promissory note, related party	(5,500,000)
Proceeds from capital contribution	12,000,000
Net cash provided by financing activities	40,955,000	13,973,000
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	7,078,000	(1,232,000)
CASH AND CASH EQUIVALENTS–Beginning of period	4,180,000	1,661,000
CASH AND CASH EQUIVALENTS–End of period	11,258,000	429,000
SUPPLEMENTAL DISCLOSURES OF NONCASH INVESTING AND FINANCING ACTIVITIES:
Cash paid for interest	275,000
Purchase of property and equipment in accounts payable	52,000
Conversion of redeemable convertible preferred stock into common stock	111,718,000
Conversion of convertible preferred stock into common stock	7,684,000
Issuance of common stock	$ 1,000
Series D Redeemable Convertible Preferred Stock [Member]
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of Series D redeemable convertible preferred stock, net of issuance costs		$ 7,982,000

Company and Nature of Business

9 Months Ended

Sep. 30, 2018

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 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.

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.

Liquidity

These 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 $17.7 million and $15.1 million for the nine months ended September 30, 2018 and 2017, respectively, an accumulated deficit of $208.3 million and $187.2 million and stockholders’ equity of $23.7 million as of September 30, 2018 and stockholders’ deficit of $113.5 million as of December 31, 2017, 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 condensed 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. The Company believes that its existing cash and cash equivalents and marketable securities balances of $11.3 million and $16.1 million as of September 30, 2018, respectively, are sufficient to provide liquidity to fund its operations through the 3^rd quarter of 2019. Management is currently evaluating different strategies to obtain the required funding of future operations and growth. 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, or a secondary public offering of the Company’s common stock. 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.

Summary of Significant Accounting Policies

9 Months Ended

Sep. 30, 2018

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, 2018. 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 audited consolidated financial statements and related notes contained in the final prospectus related to the Company’s IPO (the “Prospectus”), which was filed with the SEC on August 10, 2018 pursuant to Rule 424(b) of the Securities Act of 1933, as amended, relating to the Company’s Registration Statement on Form S-1 (File No. 333-226103). The accounting policies followed in the preparation of these consolidated condensed financial statements are consistent in all material respects with those presented in Note 2 to the financial statements included in the Company’s Prospectus, except for the Company’s accounting policy, as described below, for its recently purchased 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, which is a separate component of stockholders’ equity (deficit). 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 condensed 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.

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 May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standard Update (“ASU”) No. 2014-09, Revenue from Contracts with Customers, which supersedes the revenue recognition requirements in Accounting Standards Codification (“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 plans to adopt the new revenue standards using the modified retrospective method when they become effective for the Company, which is at the earlier of losing the emerging growth company status or the Company’s fiscal year beginning January 1, 2019. The Company is in the process of evaluating the effect that the new revenue standards will have on its condensed consolidated financial statements and related disclosures.

In February 2016, the FASB issued ASU No. 2016-02, Leases, which supersedes the 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, and interim periods therein. 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 with modified retrospective method for fiscal year 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 August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows: Classification of Certain Cash Receipts and Cash Payments, which eliminates the diversity in practice related to the classification of certain cash receipts and payments for debt prepayment or extinguishment costs, the maturing of a zero coupon bond, the settlement of contingent liabilities arising from a business combination, proceeds from insurance settlements, distributions from certain equity method investees and beneficial interests obtained in a financial asset securitization. ASU No. 2016-15 designates the appropriate cash flow classification, including requirements to allocate certain components of these cash receipts and payments among operating, investing and financing activities. ASU No. 2016-15 should be applied using the retrospective transition method, requiring adjustment to all comparative periods presented, unless it is impracticable for some of the amendments, in which case those amendments would be made prospectively as of the earliest date practicable. ASU No. 2016-15 is effective for the Company at the earlier of losing the emerging growth company status or the Company’s fiscal year beginning January 1, 2019, and interim periods therein. The Company early adopted the new standard on January 1, 2018 using the retrospective transition method. The adoption of ASU No. 2016-15 did not have a material impact on its condensed consolidated financial statements and related disclosures.

In May 2017, the FASB issued ASU No. 2017-09, Compensation-Stock Compensation: Scope of Modification Accounting, which provides clarified guidance on applying modification accounting to changes in the terms or conditions of a share-based payment award. Changes that do not impact the award’s fair value, vesting conditions, or classification as an equity or liability instrument will not be subject to modification accounting. ASU No. 2017-09 is effective prospectively for the Company at the earlier of losing the emerging growth company status or the Company’s fiscal year beginning January 1, 2019, and interim periods therein. The Company early adopted the new standard on January 1, 2018 using the prospective method, and the adoption of ASU No. 2017-09 did not have a material impact on its condensed consolidated financial statements and related disclosures.

In March 2016, the FASB issued ASU No. 2016-09, Compensation–Stock Compensation: Improvements to Employee Share-Based Payment Accounting, which simplifies several aspects of the accounting for share-based payment transactions, including the income tax consequences, application of award forfeitures to expense, classification of awards as either equity or liabilities, and classification on the statement of cash flows. The new standard is effective for the Company’s fiscal year effective January 1, 2018. On January 1, 2017, the Company adopted the standard early and there was no material impact on its condensed consolidated financial statements and related disclosures.

Balance Sheet Components

9 Months Ended

Sep. 30, 2018

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 September 30, 2018			As of December 31, 2017
Leasehold improvements	$	3,145		$	3,140
Research equipment		3,102			2,998
Furniture and fixtures		350			350
Computer equipment		214			214
Property and equipment, gross		6,811			6,702
Less: accumulated depreciation and amortization		(6,267	)		(6,101	)
Property and equipment, net	$	544		$	601

Depreciation and amortization expense related to property and equipment was $54,000 for the three months ended September 30, 2018 and 2017, and $166,000 and $152,000 for the nine months ended September 30, 2018 and 2017, respectively.

Accrued Expenses

Accrued expenses consist of the following (in thousands):

	As of September 30, 2018		As of December 31, 2017
Accrued clinical trial cost	$	3,260	$	891
Accrued consulting and legal		287		239
Accrued payroll and related benefits		227		311
Accrued interest		—		192
Accrued other		44		324
Accrued expenses	$	3,818	$	1,957

Marketable Securities

9 Months Ended

Sep. 30, 2018

Investments Debt And Equity Securities [Abstract]

Marketable Securities

4.	MARKETABLE SECURITIES

As of September 30, 2018, the fair value of available-for-sale marketable securities was as follows (in thousands):

	September 30, 2018
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Marketable securities:
U.S. Treasury securities	$	16,121	$	—	$	—	$	16,121
	$	16,121	$	—	$	—	$	16,121

All of the Company’s available-for-sale marketable securities at September 30, 2018 are maturing in one year or less.

Fair Value of Financial Measurements

9 Months Ended

Sep. 30, 2018

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):


	September 30, 2018
	Fair Value		Level 1		Level 2		Level 3
Financial Assets:
Cash equivalents:
Money market fund	$	1,512	$	1,512	$	—	$	—
U. S. Treasury securities		6,741		—		6,741		—
Marketable securities:
U. S. Treasury securities		16,121		—		16,121		—
Total Financial Assets	$	24,374	$	1,512	$	22,862	$	—

	December 31, 2017
	Fair Value		Level 1		Level 2		Level 3
Financial Assets:
Cash equivalents:
Money market fund	$	1,011	$	1,011	$	—	$	—
Total Financial Assets	$	1,011	$	1,011	$	—	$	—
Financial Liabilities:
Derivative liability	$	369	$	—	$	—	$	369
Total Financial Liabilities	$	369	$	—	$	—	$	369

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 nine months ended September 30, 2018.

The following table sets forth a summary of the changes in the fair value of the Company’s Level 3 financial instruments as follows (in thousands):

	Derivative Liability
Balance – December 31, 2017	$	369
Change in fair value		(369	)
Balance – September 30, 2018	$	—

Level 3 instruments consist of the Company’s embedded derivative liabilities related to conversion features within the outstanding convertible promissory notes as of December 31, 2017, and a free-standing derivative related to an option to purchase shares in a future equity financing as of December 31, 2017.

The fair value of the derivative liabilities was measured using a with-and-without valuation methodology. Inputs used to determine the estimated fair value of the derivative instruments include the probability estimates of potential settlement scenarios for the convertible promissory notes, a present value discount rate and an estimate of the expected timing of settlement. Certain unobservable inputs used in the fair value measurement of the derivative instruments associated with the convertible promissory notes are the scenario probabilities and the discount rate estimated at the valuation date. Generally, an increase or decrease in the discount rate would result in a directionally opposite impact to the fair value measurement of the derivative instruments. Also, changes in the probability scenarios would have varying impacts depending on the weighting of each specific scenario.

From the proceeds of the convertible promissory notes, a portion equal to the fair value of the derivative instruments was recognized as an additional debt discount and as derivative liabilities on the condensed consolidated balance sheet upon issuance of the respective convertible promissory notes. The derivative liabilities require periodic remeasurements to fair value while the derivative is outstanding and, accordingly, the Company recognized a gain of $31,000 and $157,000 from the remeasurement of the derivative liabilities associated with the convertible promissory notes for the three months ended September 30, 2018 and 2017, respectively, and a gain of $369,000 and a loss of $214,000 for the nine months ended September 30, 2018 and 2017, respectively, and presents such amounts in its condensed consolidated statements of operations and comprehensive loss as changes in fair value of derivative liabilities. As of September 30, 2018 the convertible promissory notes had been paid in full.

- 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

9 Months Ended

Sep. 30, 2018

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. Under the VX3 License Agreement, the Company granted VX3 the license to use, make, have made, sell, offer and import VX15 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 VX15 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 VX15 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 controls 90% and 96% of VX3’s voting interest as of September 30, 2018 and December 31, 2017, respectively. 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 September 30, 2018.

For the nine months ended September 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

9 Months Ended

Sep. 30, 2018

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. The Company received quarterly service payments in the amount of $138,000 under the research agreement, of which $69,000 was recognized as service revenue for the nine months ended September 30, 2018. Deferred revenue as of December 31, 2017 totaled $69,000. The research agreement expired in June 2018.

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 $188,000 was recognized as revenue from the amortization of this upfront fee for the three months and nine months ended September 30, 2018, respectively. The remaining $42,000 is reported as deferred revenue as of September 30, 2018. The Company also received $66,000 and $199,000 service fee payments for work conducted under the agreement, for the three months and nine months ended September 30, 2018, respectively. This agreement will expire upon the expiration of both research programs and all evaluation and testing periods.

Heptares Therapeutics, Ltd.

In June 2018, the Company entered into a three-month research service agreement with Heptares Therapeutics, Ltd. (“Heptares”) to provide research services to Heptares. Under the agreement, Heptares will provide the Company compounds, materials or samples, and the Company will perform feasibility services to allow Heptares to evaluate the feasibility of the Company’s technology. The Company received a payment of $69,000 from Heptares under the research agreement which was recognized as service revenue for the three months ended September 30, 2018.

Convertible Promissory Notes

9 Months Ended

Sep. 30, 2018

Debt Disclosure [Abstract]

Convertible Promissory Notes

8.	CONVERTIBLE PROMISSORY NOTES

The following table sets forth a summary of the outstanding convertible promissory notes (in thousands):

	As of December 31, 2017
June 2016 Note	$	1,500
Unamortized debt discount		(316	)
Net June 2016 Note		1,184
January 2017 Notes		4,000
Unamortized debt discount		(2,371	)
Net January 2017 Notes		1,629
Total convertible promissory notes, related parties	$	2,813

As of September 30, 2018, the Company did not have any convertible promissory notes outstanding. See “Conversion and Repayment of Convertible Promissory Notes” below.

June 2016 Note

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, together with accrued interest, was convertible (i) automatically upon a future qualifying financing event, which includes the sale of shares in a future preferred stock financing with gross proceeds of at least $5.0 million or the issuance of shares of common stock in an IPO, (ii) upon a change of control (unless the lenders elect to treat such event as a default), or (iii) upon a future non-qualifying financing event at the election of the lenders. Upon a future qualifying financing event, the outstanding principal, together with accrued interest, would convert into shares of the newly issued securities at 85% of the price paid in the financing. However, a closing of the sale of the Company’s convertible preferred stock with minimum gross proceeds of $5.0 million within 90 days of the effective date of the related convertible promissory notes was not considered a qualifying financing event, and the outstanding principal, together with accrued interest, would convert into shares of the newly issued securities at 100% of the price paid in financing. Upon the election to convert the convertible promissory notes in the event of a change of control, the outstanding principal, together with accrued interest, would convert based on the conversion price of the Series C redeemable convertible preferred stock, which was $18.20 per share as of December 31, 2017. Upon the election to convert the convertible promissory notes in the event of a non-qualifying financing event, the outstanding principal, together with accrued interest, would convert based on the lowest price per share paid for in the financing. The June 2016 Note was paid in full on August 17, 2018. See “Conversion and 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 “Conversion and Repayment of Convertible Promissory Notes” below.

Conversion Feature and Option

The conversion terms of the January 2017 Notes were similar to the June 2016 Note, except that the conversion price of the January 2017 Notes upon a qualifying financing was the lower of (1) $18.20 per share, or (2) 85% of the price per share of the newly issued securities. In connection with the issuance of the January 2017 Notes, the Company and the related party also entered into a side letter agreement that granted the related party an exclusive option to acquire shares with a fair value of up to $4.0 million in the next qualifying financing (the “option arrangement”), at a price per share equal to the conversion price of the January 2017 Notes, which option arrangement was waived on March 8, 2018.

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 $17,000 and $324,000 for the amortization of the debt discounts during the three months ended September 30, 2018 and 2017, respectively, and $308,000 and $886,000 during the nine months ended September 30, 2018 and 2017, respectively.

Conversion and Repayment of Convertible Promissory Notes

In August 2016, the Company raised $10.7 million in Series D redeemable convertible preferred stock financing, which qualified as a Qualified Financing (preferred stock financing with gross proceeds of at least $5.0 million) for several convertible promissory notes issued in prior years. The outstanding principal and accrued interest of these convertible promissory notes totaling $27.1 million was converted into 17,485,445 shares of Series D redeemable convertible preferred stock at $1.547 per share, or 85% of the Series D redeemable convertible preferred stock issuance price of $1.82 per share, as specified in each convertible promissory note agreement. The $8.6 million unamortized debt discount was reclassified into Series D redeemable convertible preferred stock. The related embedded derivative liabilities totaling $4.8 million were marked to fair value on the conversion date and were included in the accounting for the conversion of the convertible promissory notes to Series D redeemable convertible preferred stock.

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 statements of operations in the nine months ended September 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.

As of December 31, 2017, the Company was in compliance with all financial covenants in the convertible promissory notes.

Commitment and Contingencies

9 Months Ended

Sep. 30, 2018

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 September 30, 2018, the future minimum payments for the operating lease is $350,000.

Rent expense incurred under the operating lease was $42,000 for the three months ended September 30, 2017 and 2018, and $126,000 for the nine months ended September 30, 2017 and 2018.

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 September 30, 2018 and December 31, 2017, the Company was not involved in any material legal proceedings.

Common Stock Reserved For Issuance

9 Months Ended

Sep. 30, 2018

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 September 30, 2018		As of December 31, 2017
Conversion of outstanding preferred stock		—		7,039,155
Shares underlying outstanding stock options		403,686		420,956
Shares available for future stock option grants		425,000		19,034
Exchange of Vaccinex Products, LP units		1,202,566		1,202,566
Conversion of VX3 units		1,318,797		659,400
Total shares of common stock reserved		3,350,049		9,341,111

Stock-Based Compensation

9 Months Ended

Sep. 30, 2018

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-Based Compensation

11.	STOCK-BASED COMPENSATION

Employee Equity Plans

In 2011, the Company adopted the 2011 Employee Equity Plan (the “2011 Plan”) for the purpose of granting stock, stock option, and stock appreciation rights awards to employees, advisors and consultants. Stock options granted under the 2011 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 2011 Plan expire in five or ten years from the date of grant. Additionally, in August 2018, the Company adopted its 2018 Omnibus Incentive Plan (the “2018 Plan”). Under the 2018 Plan, 425,000 shares of common stock were reserved for future issuance to employees, directors, and consultants. The Company will not make any further grants under the 2011 Plan.

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
Balance as of December 31, 2017		420,956		$	9.20		7.4	$	5,021
Granted		28,000			13.60
Exercised		(700	)		7.10
Canceled		(44,570	)		7.10
Balance as of September 30, 2018		403,686		$	9.71		6.7	$	4,598
Exercisable as of September 30, 2018		357,014		$	9.49		6.5	$	4,146

The weighted-average grant date fair value of stock options granted to employees for the nine months ended September 30, 2018 and 2017 was $15.63 and $9.00 per share, respectively. The aggregate grant date fair value of stock options that vested during the nine months ended September 30, 2018 and 2017 was $188,000 and $176,000, 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 September 30, 2018 and December 31, 2017. 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. The intrinsic value of stock options exercised was $11,000 and $13,000 during the nine months ended September 30, 2018 and 2017, respectively.

As of September 30, 2018 and December 31, 2017, total unrecognized compensation cost related to stock options granted to employees was $471,000 and $216,000, respectively, which is expected to be recognized over a weighted-average period of 3.1 and 1.9 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.

On January 1, 2017, the Company adopted ASU No. 2016-09 and started to account for forfeitures of stock options as they occur. The Company recorded the cumulative effect adjustment to accumulated deficit and the impact was not material.

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

	Nine Months Ended September 30,
	2018			2017
Expected term (in years)		6.0			6.0
Expected volatility		75	%		75	%
Risk-free interest rate		2.6	%		2.0	%
Expected dividend yield		—	%		—	%

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

	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
Research and development	$	16	$	14	$	50	$	40
General and administrative		27		175		81		209
Total stock-based compensation expense	$	43	$	189	$	131	$	249

Income Taxes

9 Months Ended

Sep. 30, 2018

Income Tax Disclosure [Abstract]

Income Taxes

12.	INCOME TAXES

No provision for income taxes was recorded in the three and nine months ended September 30, 2018 and 2017. The Company remains in a cumulative loss position with a full valuation allowance recorded against its net deferred income tax assets as of September 30, 2018 and December 31, 2017.

On December 22, 2017, the Tax Cuts and Jobs Act (the “Tax Act”) was signed into law. The Tax Act makes broad and complex changes to the U.S. tax code including, but not limited to, reducing the U.S. federal corporate income tax rate. While the Tax Act reduces the U.S. federal corporate income tax rate from 35% to 21% for tax years beginning after December 31, 2017, Accounting Standards Codification 740 (“ASC 740”) requires the Company to remeasure its deferred tax balances in 2017 in accordance with the 2018 rate reduction.

The SEC staff issued Staff Accounting Bulletin 118 (“SAB 118”), which provides guidance on accounting for the tax effects of the Tax Act. SAB 118 provides a measurement period that should not extend beyond one year from the U.S. tax reform enactment date for companies to complete the accounting under ASC 740. In accordance with SAB 118, a company must reflect the income tax effects of those aspects of the U.S. tax reform for which the accounting under ASC 740 is complete. Specifically, the Company revalued its U.S. deferred tax assets and liabilities due to the federal income tax rate reduction from 35% to 21%. Since the Company has provided a full valuation allowance against its deferred tax assets, the revaluation of the deferred tax assets did not have a material impact on any period presented. The ultimate impact of the income tax effects of the Tax Act may differ due to, among other things, additional analysis, changes in interpretations, and additional regulatory guidance that may be issued as a result of the Tax Act. The accounting is expected to be complete when the Company’s 2017 U.S. corporate income tax return is filed in 2018. The Company has recorded a reduction of deferred income tax assets of $20.7 million in the year ended December 31, 2017 related to the remeasurement of our net deferred tax assets to reflect the U.S. federal corporate income tax rate reduction to 21%, which was fully offset by a change to the Company’s valuation allowance. 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 September 30, 2018 and December 31, 2017, the Company had no unrecognized income tax benefits that would affect the Company’s effective tax rate if recognized.

Net Loss Per Share Attributable to Common Stockholders

9 Months Ended

Sep. 30, 2018

Earnings Per Share [Abstract]

Net Loss Per Share Attributable to Common Stockholders

13.	NET LOSS PER SHARE ATTRIBUTABLE TO COMMON STOCKHOLDERS

The following table sets forth the computation of the Company’s basic and diluted net loss per share for the periods presented (in thousands, except share and per share data):

	Three Months Ended September 30,						Nine Months Ended September 30,
	2018			2017			2018			2017
Net loss	$	(6,599	)	$	(5,536	)	$	(21,069	)	$	(16,132	)
Net loss attributable to noncontrolling interests		—			—			—			—
Net loss attributable to Vaccinex, Inc.		(6,599	)		(5,536	)		(21,069	)		(16,132	)
Cumulative dividends on preferred stock		—			(809	)		—			(2,401	)
Net loss attributable to Vaccinex, Inc. common stockholders, basic and diluted	$	(6,599	)	$	(6,345	)	$	(21,069	)	$	(18,533	)
Net loss per share attributable to Vaccinex, Inc. common stockholders, basic and diluted	$	(0.93	)	$	(5.75	)	$	(6.76	)	$	(16.82	)
Weighted-average shares used in computing net loss per share attributable to Vaccinex, Inc. common stockholders, basic and diluted		7,078,715			1,102,520			3,116,695			1,101,723

The following weighted-average common stock equivalents were excluded from the calculation of diluted net income (loss) per share for the periods presented as they had an anti-dilutive effect:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
Preferred stock (if converted)		—		7,020,044		—		6,771,176
Options to purchase common stock		403,686		408,782		412,934		406,596
Contingently issuable common stock upon exchange of Vaccinex Products, LP units		1,202,566		1,202,566		1,202,566		1,202,566
Contingently issuable common stock upon exchange of VX3 units		1,318,797		—		1,103,825		—

Segment and Geographical Information

9 Months Ended

Sep. 30, 2018

Segment Reporting [Abstract]

Segment and Geographic Information

14.	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 September 30, 2018 and December 31, 2017, all long-lived assets are located in the United States.

Employee Benefit Plan

9 Months Ended

Sep. 30, 2018

Compensation And Retirement Disclosure [Abstract]

Employee Benefit Plan

15.	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 September 30, 2018 and December 31, 2017, 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

9 Months Ended

Sep. 30, 2018

Related Party Transactions

16.	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 $126,000 for each of the nine months ended September 30, 2018 and 2017.

The Company issued $1.5 million convertible promissory note to Vaccinex LLC during the year ended December 31, 2016. Vaccinex LLC is majority owned and controlled by the Company’s Chief Executive Officer. The loan balance was repaid in full on August 17, 2018.

Summary of Significant Accounting Policies (Policies)	9 Months Ended
Summary of Significant Accounting Policies (Policies)	Sep. 30, 2018
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, 2018. 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 audited consolidated financial statements and related notes contained in the final prospectus related to the Company’s IPO (the “Prospectus”), which was filed with the SEC on August 10, 2018 pursuant to Rule 424(b) of the Securities Act of 1933, as amended, relating to the Company’s Registration Statement on Form S-1 (File No. 333-226103). The accounting policies followed in the preparation of these consolidated condensed financial statements are consistent in all material respects with those presented in Note 2 to the financial statements included in the Company’s Prospectus, except for the Company’s accounting policy, as described below, for its recently purchased marketable securities.
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, which is a separate component of stockholders’ equity (deficit). 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 condensed 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.
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 May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standard Update (“ASU”) No. 2014-09, Revenue from Contracts with Customers, which supersedes the revenue recognition requirements in Accounting Standards Codification (“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 plans to adopt the new revenue standards using the modified retrospective method when they become effective for the Company, which is at the earlier of losing the emerging growth company status or the Company’s fiscal year beginning January 1, 2019. The Company is in the process of evaluating the effect that the new revenue standards will have on its condensed consolidated financial statements and related disclosures. In February 2016, the FASB issued ASU No. 2016-02, Leases, which supersedes the 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, and interim periods therein. 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 with modified retrospective method for fiscal year 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 August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows: Classification of Certain Cash Receipts and Cash Payments, which eliminates the diversity in practice related to the classification of certain cash receipts and payments for debt prepayment or extinguishment costs, the maturing of a zero coupon bond, the settlement of contingent liabilities arising from a business combination, proceeds from insurance settlements, distributions from certain equity method investees and beneficial interests obtained in a financial asset securitization. ASU No. 2016-15 designates the appropriate cash flow classification, including requirements to allocate certain components of these cash receipts and payments among operating, investing and financing activities. ASU No. 2016-15 should be applied using the retrospective transition method, requiring adjustment to all comparative periods presented, unless it is impracticable for some of the amendments, in which case those amendments would be made prospectively as of the earliest date practicable. ASU No. 2016-15 is effective for the Company at the earlier of losing the emerging growth company status or the Company’s fiscal year beginning January 1, 2019, and interim periods therein. The Company early adopted the new standard on January 1, 2018 using the retrospective transition method. The adoption of ASU No. 2016-15 did not have a material impact on its condensed consolidated financial statements and related disclosures. In May 2017, the FASB issued ASU No. 2017-09, Compensation-Stock Compensation: Scope of Modification Accounting, which provides clarified guidance on applying modification accounting to changes in the terms or conditions of a share-based payment award. Changes that do not impact the award’s fair value, vesting conditions, or classification as an equity or liability instrument will not be subject to modification accounting. ASU No. 2017-09 is effective prospectively for the Company at the earlier of losing the emerging growth company status or the Company’s fiscal year beginning January 1, 2019, and interim periods therein. The Company early adopted the new standard on January 1, 2018 using the prospective method, and the adoption of ASU No. 2017-09 did not have a material impact on its condensed consolidated financial statements and related disclosures. In March 2016, the FASB issued ASU No. 2016-09, Compensation–Stock Compensation: Improvements to Employee Share-Based Payment Accounting, which simplifies several aspects of the accounting for share-based payment transactions, including the income tax consequences, application of award forfeitures to expense, classification of awards as either equity or liabilities, and classification on the statement of cash flows. The new standard is effective for the Company’s fiscal year effective January 1, 2018. On January 1, 2017, the Company adopted the standard early and there was no material impact on its condensed consolidated financial statements and related disclosures.

Balance Sheet Components (Tables)

9 Months Ended

Sep. 30, 2018

Balance Sheet Related Disclosures [Abstract]

Property and Equipment

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

	As of September 30, 2018			As of December 31, 2017
Leasehold improvements	$	3,145		$	3,140
Research equipment		3,102			2,998
Furniture and fixtures		350			350
Computer equipment		214			214
Property and equipment, gross		6,811			6,702
Less: accumulated depreciation and amortization		(6,267	)		(6,101	)
Property and equipment, net	$	544		$	601

Accrued Expenses

Accrued expenses consist of the following (in thousands):

	As of September 30, 2018		As of December 31, 2017
Accrued clinical trial cost	$	3,260	$	891
Accrued consulting and legal		287		239
Accrued payroll and related benefits		227		311
Accrued interest		—		192
Accrued other		44		324
Accrued expenses	$	3,818	$	1,957

Marketable Securities (Tables)

9 Months Ended

Sep. 30, 2018

Investments Debt And Equity Securities [Abstract]

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

As of September 30, 2018, the fair value of available-for-sale marketable securities was as follows (in thousands):

	September 30, 2018
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Marketable securities:
U.S. Treasury securities	$	16,121	$	—	$	—	$	16,121
	$	16,121	$	—	$	—	$	16,121

Fair Value of Financial Measurements (Tables)

9 Months Ended

Sep. 30, 2018

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):


	September 30, 2018
	Fair Value		Level 1		Level 2		Level 3
Financial Assets:
Cash equivalents:
Money market fund	$	1,512	$	1,512	$	—	$	—
U. S. Treasury securities		6,741		—		6,741		—
Marketable securities:
U. S. Treasury securities		16,121		—		16,121		—
Total Financial Assets	$	24,374	$	1,512	$	22,862	$	—

	December 31, 2017
	Fair Value		Level 1		Level 2		Level 3
Financial Assets:
Cash equivalents:
Money market fund	$	1,011	$	1,011	$	—	$	—
Total Financial Assets	$	1,011	$	1,011	$	—	$	—
Financial Liabilities:
Derivative liability	$	369	$	—	$	—	$	369
Total Financial Liabilities	$	369	$	—	$	—	$	369

Summary of Changes in Fair Value of Level 3 Financial Instruments

The following table sets forth a summary of the changes in the fair value of the Company’s Level 3 financial instruments as follows (in thousands):

	Derivative Liability
Balance – December 31, 2017	$	369
Change in fair value		(369	)
Balance – September 30, 2018	$	—

- 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

Convertible Promissory Notes (Tables)

9 Months Ended

Sep. 30, 2018

Debt Disclosure [Abstract]

Summary of Outstanding Convertible Promissory Notes

The following table sets forth a summary of the outstanding convertible promissory notes (in thousands):

	As of December 31, 2017
June 2016 Note	$	1,500
Unamortized debt discount		(316	)
Net June 2016 Note		1,184
January 2017 Notes		4,000
Unamortized debt discount		(2,371	)
Net January 2017 Notes		1,629
Total convertible promissory notes, related parties	$	2,813

Common Stock Reserved For Issuance (Tables)

9 Months Ended

Sep. 30, 2018

Equity [Abstract]

Common Stock Reserved for Potential Future Issuances

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

	As of September 30, 2018		As of December 31, 2017
Conversion of outstanding preferred stock		—		7,039,155
Shares underlying outstanding stock options		403,686		420,956
Shares available for future stock option grants		425,000		19,034
Exchange of Vaccinex Products, LP units		1,202,566		1,202,566
Conversion of VX3 units		1,318,797		659,400
Total shares of common stock reserved		3,350,049		9,341,111

Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2018

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
Balance as of December 31, 2017		420,956		$	9.20		7.4	$	5,021
Granted		28,000			13.60
Exercised		(700	)		7.10
Canceled		(44,570	)		7.10
Balance as of September 30, 2018		403,686		$	9.71		6.7	$	4,598
Exercisable as of September 30, 2018		357,014		$	9.49		6.5	$	4,146

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:

	Nine Months Ended September 30,
	2018			2017
Expected term (in years)		6.0			6.0
Expected volatility		75	%		75	%
Risk-free interest rate		2.6	%		2.0	%
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 September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
Research and development	$	16	$	14	$	50	$	40
General and administrative		27		175		81		209
Total stock-based compensation expense	$	43	$	189	$	131	$	249

Net Loss Per Share Attributable to Common Stockholders (Tables)

9 Months Ended

Sep. 30, 2018

Earnings Per Share [Abstract]

Computation of Basic and Diluted Net Loss Per Share

The following table sets forth the computation of the Company’s basic and diluted net loss per share for the periods presented (in thousands, except share and per share data):

	Three Months Ended September 30,						Nine Months Ended September 30,
	2018			2017			2018			2017
Net loss	$	(6,599	)	$	(5,536	)	$	(21,069	)	$	(16,132	)
Net loss attributable to noncontrolling interests		—			—			—			—
Net loss attributable to Vaccinex, Inc.		(6,599	)		(5,536	)		(21,069	)		(16,132	)
Cumulative dividends on preferred stock		—			(809	)		—			(2,401	)
Net loss attributable to Vaccinex, Inc. common stockholders, basic and diluted	$	(6,599	)	$	(6,345	)	$	(21,069	)	$	(18,533	)
Net loss per share attributable to Vaccinex, Inc. common stockholders, basic and diluted	$	(0.93	)	$	(5.75	)	$	(6.76	)	$	(16.82	)
Weighted-average shares used in computing net loss per share attributable to Vaccinex, Inc. common stockholders, basic and diluted		7,078,715			1,102,520			3,116,695			1,101,723

Weighted-Average Common Stock Equivalents Excluded from Calculation of Diluted Net Income (Loss) Per Share as They Had Anti-Dilutive Effect

The following weighted-average common stock equivalents were excluded from the calculation of diluted net income (loss) per share for the periods presented as they had an anti-dilutive effect:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
Preferred stock (if converted)		—		7,020,044		—		6,771,176
Options to purchase common stock		403,686		408,782		412,934		406,596
Contingently issuable common stock upon exchange of Vaccinex Products, LP units		1,202,566		1,202,566		1,202,566		1,202,566
Contingently issuable common stock upon exchange of VX3 units		1,318,797		—		1,103,825		—

Company and Nature of Business - Additional Information (Details) $ / shares in Units, $ in Thousands		9 Months Ended
	Aug. 09, 2018 USD ($) $ / shares shares	Sep. 30, 2018 USD ($) $ / shares shares	Sep. 30, 2017 USD ($)	Dec. 31, 2017 USD ($) $ / shares	Dec. 31, 2016 USD ($)
Organization Consolidation And Presentation Of Financial Statements [Line Items]
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
Cash flow from operations		(17,719)	$ (15,140)
Accumulated deficit		208,318		$ 187,249
Stockholders' equity (deficit)		23,745	(122,933)	(113,490)	$ (107,065)
Cash and cash equivalents		11,258	$ 429	$ 4,180	$ 1,661
Marketable securities		16,121
Common Stock
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Stockholders' equity (deficit)		$ 1
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	3,333,334

Balance Sheet Components - Property and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 6,811	$ 6,702
Less: accumulated depreciation and amortization	(6,267)	(6,101)
Property and equipment, net	544	601
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	3,145	3,140
Research Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	3,102	2,998
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	Sep. 30, 2018	Dec. 31, 2017
Payables And Accruals [Abstract]
Accrued clinical trial cost	$ 3,260	$ 891
Accrued consulting and legal	287	239
Accrued payroll and related benefits	227	311
Accrued interest		192
Accrued other	44	324
Accrued expenses	$ 3,818	$ 1,957

Marketable Securities - Summary of the Fair Value of Available-for-sale Marketable Securities (Details) $ in Thousands	Sep. 30, 2018 USD ($)
Marketable Securities [Line Items]
Securities Available for Sale, Amortized Cost	$ 16,121
Securities Available for Sale, Fair Value	16,121
U.S. Treasury Securities
Marketable Securities [Line Items]
Securities Available for Sale, Amortized Cost	16,121
Securities Available for Sale, Fair Value	$ 16,121

Fair Value of Financial Measurements - Summary of Fair Value of Financial Assets by Level within Fair Value Hierarchy (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Financial Assets:
Marketable securities, Fair value disclosure	$ 16,121
Financial Liabilities:
Derivative liability		$ 369
U.S. Treasury Securities
Financial Assets:
Marketable securities, Fair value disclosure	16,121
Fair Value Measurements Recurring
Financial Assets:
Total Financial Assets	24,374	1,011
Financial Liabilities:
Derivative liability		369
Total Financial Liabilities		369
Fair Value Measurements Recurring \| Money Market Funds
Financial Assets:
Cash equivalents, Fair value disclosure	1,512	1,011
Fair Value Measurements Recurring \| U.S. Treasury Securities
Financial Assets:
Cash equivalents, Fair value disclosure	6,741
Marketable securities, Fair value disclosure	16,121
Fair Value Measurements Recurring \| Level 1
Financial Assets:
Total Financial Assets	1,512	1,011
Fair Value Measurements Recurring \| Level 1 \| Money Market Funds
Financial Assets:
Cash equivalents, Fair value disclosure	1,512	1,011
Fair Value Measurements Recurring \| Level 2
Financial Assets:
Total Financial Assets	22,862
Fair Value Measurements Recurring \| Level 2 \| U.S. Treasury Securities
Financial Assets:
Cash equivalents, Fair value disclosure	6,741
Marketable securities, Fair value disclosure	$ 16,121
Fair Value Measurements Recurring \| Level 3
Financial Liabilities:
Derivative liability		369
Total Financial Liabilities		$ 369

Fair Value of Financial Measurements - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Gain (loss) on remeasurement of derivative liabilities associated with convertible promissory notes	$ 31,000	$ 157,000	$ 369,000	$ (214,000)
Fair Value Measurements Recurring
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

Fair Value of Financial Measurements - Summary of Changes in Fair Value of Level 3 Financial Instruments (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2018 USD ($)
Fair Value Disclosures [Abstract]
Beginning balance	$ 369
Change in fair value	$ (369)

License and Services Agreement - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended		9 Months Ended	12 Months Ended
	Mar. 31, 2018	Nov. 30, 2017	Sep. 30, 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 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%	96.00%
Proceeds from capital contribution			$ 12,000

Collaboration Agreements - Additional Information (Details)	1 Months Ended		3 Months Ended	9 Months Ended	12 Months Ended
	Nov. 30, 2017 USD ($) TargetAntigen Milestone	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)
Merck Sharp & Dohme Corp.
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Quarterly service payments received under research agreement		$ 138,000
Service revenue recognized				$ 69,000
Remaining deferred revenue recognized					$ 69,000
Surface Oncology, Inc.
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Quarterly service payments received under research agreement			$ 66,000	199,000	$ 250,000
Service revenue recognized			63,000	188,000
Remaining deferred revenue recognized			42,000	$ 42,000
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
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]
Quarterly service payments received under research agreement			$ 69,000,000

Convertible Promissory Notes - Summary of the Outstanding Convertible Promissory Notes (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Oct. 31, 2017	Aug. 31, 2017	Apr. 30, 2017	Jan. 31, 2017
Debt Instrument [Line Items]
Convertible promissory note to related party noncurrent	$ 2,813
June 2016 Note
Debt Instrument [Line Items]
Long-term debt, gross	1,500
Unamortized debt discount	(316)
Long-term debt	1,184
January 2017 Notes
Debt Instrument [Line Items]
Long-term debt, gross	4,000	$ 6,000	$ 6,000	$ 6,000	$ 4,000
Unamortized debt discount	(2,371)
Long-term debt	$ 1,629

Convertible Promissory Notes - Additional Information (Details) - USD ($)	1 Months Ended								3 Months Ended		9 Months Ended
	Mar. 31, 2018	Nov. 30, 2017	Oct. 31, 2017	Aug. 31, 2017	Apr. 30, 2017	Jan. 31, 2017	Aug. 31, 2016	Jun. 30, 2016	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Debt Instrument [Line Items]
Proceeds from initial public offering of common stock, net of commissions and underwriting discounts											$ 37,125,000
Interest expense									$ 17,000	$ 324,000	308,000	$ 886,000
Derivative liability								$ 31,000,000,000
Loss on extinguishment of related party convertible promissory note									199,000		2,379,000
Convertible Promissory Notes \| Series D Redeemable Convertible Preferred Stock [Member]
Debt Instrument [Line Items]
Issuance of convertible preferred stock							$ 10,700,000
Convertible promissory notes							$ 27,100,000
Converted shares							17,485,445
Preferred stock, par value							$ 1.547
Percentage of convertible preferred stock							85.00%
Convertible preferred stock issuance price							$ 1.82
Debt instrument unamortized discount							$ 8,600,000
Derivative liability							4,800,000
Convertible Promissory Notes \| Series D Redeemable Convertible Preferred Stock [Member] \| Minimum
Debt Instrument [Line Items]
Issuance of convertible preferred stock gross							5,000,000
June 2016 Note
Debt Instrument [Line Items]
Long-term debt, gross													$ 1,500,000
Annual interest rate								8.00%
Debt instrument maturity term								3 years
Increase of interest rate								12.00%
Proceeds from initial public offering of common stock, net of commissions and underwriting discounts								$ 5,000,000
Principal percentage price for newly issued securities in non-qualifying financing event								85.00%
Convertible preferred stock with minimum gross proceeds								$ 5,000,000
Debt instrument trading period								90 days
Principal percentage price for newly issued securities in qualifying financing event								100.00%
Debt instrument unamortized discount													$ 316,000
June 2016 Note \| Series C redeemable preferred stock
Debt Instrument [Line Items]
Convertible conversion price per share													$ 18.20
June 2016 Note \| Convertible Promissory Notes
Debt Instrument [Line Items]
Long-term debt, gross									$ 0		$ 0
January 2017 Notes
Debt Instrument [Line Items]
Long-term debt, gross			$ 6,000,000	$ 6,000,000	$ 6,000,000	$ 4,000,000							$ 4,000,000
Annual interest rate			2.00%	2.00%	2.00%	0.00%
Debt instrument maturity term						3 years
Principal percentage price for newly issued securities in qualifying financing event						85.00%
Convertible conversion price per share						$ 18.20
Aggregate convertible promissory note issuance amount						$ 10,000,000
Debt Instrument, payment amount						6,000,000
Debt instrument unamortized discount													$ 2,371,000
Repayments of convertible debt	$ 4,000,000
January 2017 Notes \| Maximum
Debt Instrument [Line Items]
Fair value of acquire shares						4,000,000
January 2017 Notes \| Convertible Promissory Notes
Debt Instrument [Line Items]
Long-term debt, gross			$ 4,000,000		$ 2,000,000	$ 4,000,000
Debt instrument unamortized discount							2,200,000
Repayments of convertible debt	$ 4,000,000	$ 4,000,000			$ 2,000,000
Derivative liabilities written off with conversion of repayment							$ 300,000

Commitments and Contingencies - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Commitments And Contingencies [Line Items]
Royalty payments, percent of net sales			1.00%
Monthly rental payments	$ 14,000		$ 14,000
Future minimum payments for operating lease	350,000		350,000
Rent expense incurred under operating lease	$ 42,000	$ 42,000	126,000	$ 126,000
Contract Termination
Commitments And Contingencies [Line Items]
Termination payment			$ 25,500

Common Stock Reserved For Issuance - Common Stock Reserved For Potential Future Issuances (Details) - shares	Sep. 30, 2018	Dec. 31, 2017
Class Of Stock [Line Items]
Total shares of common stock reserved	3,350,049	9,341,111
Shares Underlying Outstanding Stock Options
Class Of Stock [Line Items]
Total shares of common stock reserved	403,686	420,956
Shares Available For Future Stock Option Grants
Class Of Stock [Line Items]
Total shares of common stock reserved	425,000	19,034
Conversion of Outstanding Preferred Stock
Class Of Stock [Line Items]
Total shares of common stock reserved		7,039,155
Exchange of Vaccinex Products, LP Units
Class Of Stock [Line Items]
Total shares of common stock reserved	1,202,566	1,202,566
Conversion of VX3 Units
Class Of Stock [Line Items]
Total shares of common stock reserved	1,318,797	659,400

Stock-Based Compensation - Additional Information (Details) - USD ($)	9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total shares of common stock reserved	3,350,049		9,341,111
Weighted-average grant date fair value of stock options granted to employees	$ 15.63	$ 9.00
Options granted	28,000
Aggregate grant date fair value of stock options vested	$ 188,000	$ 176,000
Intrinsic value of stock options exercised	11,000	$ 13,000
Total unrecognized compensation cost related to stock options granted to employees	$ 471,000		$ 216,000
Maximum contractual life for options granted	10 years
Expected dividend yield	0.00%
2018 Omnibus Incentive Plan \| Director \| Employees
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total shares of common stock reserved	425,000
Minimum \| 2011 Employee Equity Plan
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	3 years 1 month 6 days		1 year 10 months 24 days
Expected term of stock option	6 years	6 years
Employee Stock Options \| Minimum \| 2011 Employee Equity Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options granted, vesting period	0 years
Stock options granted, expiration year	5 years
Employee Stock Options \| Maximum \| 2011 Employee Equity Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options granted, vesting period	8 years
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	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Options Outstanding, Options, Balance	420,956
Options Outstanding, Options, Granted	28,000
Options Outstanding, Options, Exercised	(700)
Options Outstanding, Options, Cancelled	(44,570)
Options Outstanding, Options, Balance	403,686	420,956
Options Outstanding, Options, Exercisable	357,014
Options Outstanding, Weighted-Average Exercise Price, Balance	$ 9.20
Options Outstanding, Weighted-Average Exercise Price, Granted	13.60
Options Outstanding, Weighted-Average Exercise Price, Exercised	7.10
Options Outstanding, Weighted-Average Exercise Price, Canceled	7.10
Options Outstanding, Weighted-Average Exercise Price, Balance	9.71	$ 9.20
Options Outstanding, Weighted-Average Exercise Price, Exercisable	$ 9.49
Options Outstanding Weighted-Average Remaining Contractual Life (Years), Balance	6 years 8 months 12 days	7 years 4 months 24 days
Options Outstanding Weighted-Average Remaining Contractual Life (Years), Exercisable	6 years 6 months
Options Outstanding, Aggregate Intrinsic Value, Balance	$ 5,021
Options Outstanding, Aggregate Intrinsic Value, Balance	4,598	$ 5,021
Options Outstanding, Aggregate Intrinsic Value, Exercisable	$ 4,146

Stock-Based Compensation - Grant Date Fair Value of Employee Stock Options Estimated Using Black-Scholes Option-Pricing Model with Weighted-Average Assumptions (Details)	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
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	2.60%	2.00%

Stock-Based Compensation - Total Stock-Based Compensation Expense Recognized in Condensed Consolidated Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	$ 43	$ 189	$ 131	$ 249
Research and Development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	16	14	50	40
General and Administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	$ 27	$ 175	$ 81	$ 209

Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Provision for income taxes	$ 0	$ 0	$ 0	$ 0
U.S. federal corporate income tax rate			21.00%		35.00%
Unrecognized tax benefits that would impact effective tax rate	$ 0		$ 0		$ 0

Net Loss Per Share Attributable to Common Stockholders - Computation of Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Net loss	$ (6,599)	$ (5,536)	$ (21,069)	$ (16,132)
Net loss attributable to Vaccinex, Inc.	(6,599)	(5,536)	(21,069)	(16,132)
Cumulative dividends on preferred stock		(809)		(2,401)
Net loss attributable to Vaccinex, Inc. common stockholders, basic and diluted	$ (6,599)	$ (6,345)	$ (21,069)	$ (18,533)
Net loss per share attributable to Vaccinex, Inc. common stockholders, basic and diluted	$ (0.93)	$ (5.75)	$ (6.76)	$ (16.82)
Weighted-average shares used in computing net loss per share attributable to Vaccinex, Inc. common stockholders, basic and diluted	7,078,715	1,102,520	3,116,695	1,101,723

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

- Definition

The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

+ References

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-Name Accounting Standards Codification
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+ Details

Net Loss Per Share Attributable to Common Stockholders - Weighted-Average Common Stock Equivalents Excluded from Calculation of Diluted Net Income (Loss) Per Share as They Had Anti-Dilutive Effect (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Convertible Preferred Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Preferred stock (if converted)		7,020,044		6,771,176
Employee Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Preferred stock (if converted)	403,686	408,782	412,934	406,596
Vaccinex Products, LP Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Preferred stock (if converted)	1,202,566	1,202,566	1,202,566	1,202,566
VX3 Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Preferred stock (if converted)	1,318,797		1,103,825

Segment and Geographic Information - Additional Information (Details)	9 Months Ended	12 Months Ended
	Sep. 30, 2018 BusinessActivity SegmentManager Segment	Dec. 31, 2017 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) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2016
Related Party Transaction [Line Items]
Rent expense incurred under operating lease	$ 42,000	$ 42,000	$ 126,000	$ 126,000
Proceeds from issuance of notes to related parties				$ 5,976,000
Loan repaid in full,date			Aug. 17, 2018
Vaccinex LLC \| Convertible Promissory Notes
Related Party Transaction [Line Items]
Proceeds from issuance of notes to related parties					$ 1,500,000

Marketable Securities - Additional Information (Details)	9 Months Ended
	Sep. 30, 2018
Maximum
Marketable Securities [Line Items]
Available for sale marketable securities maturity period	1 year