Acer Therapeutics (ACER) 10-K 7 Mar 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2017	Mar. 01, 2018	Jun. 30, 2017
Document And Entity Information [Abstract]
Entity Registrant Name	Acer Therapeutics Inc.
Entity Central Index Key	1,069,308
Document Type	10-K
Document Period End Date	Dec. 31, 2017
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Trading Symbol	ACER
Is Entity a Well-known Seasoned Issuer	No
Is Entity a Voluntary Filer	No
Is Entity's Reporting Status Current	Yes
Entity Filer Category	Smaller Reporting Company
Entity Public Float			$ 4,951,912
Entity Common Stock, Shares Outstanding		7,497,433
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2,017

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 15,644,355	$ 1,834,018
Prepaid expenses	881,887	540,053
Total current assets	16,526,242	2,374,071
Property and equipment, net	62,984	6,217
Other assets:
Goodwill	7,647,267	272,315
In-process research and development	118,600	118,600
Other assets	13,648	1,901
Total assets	24,368,741	2,773,104
Current liabilities:
Accounts payable	95,873	383,411
Accrued expenses	1,937,331	438,028
Total liabilities	2,033,204	821,439
Commitments
Series B Convertible Redeemable Preferred stock, $0.0001 par value; none and 970,238 shares authorized, issued and outstanding at December 31, 2017 and 2016, respectively	0	12,136,440
Stockholders’ equity (deficit):
Preferred stock, no par value; authorized 10,000,000 shares; none issued and outstanding	0	0
Common stock, $0.01 par value; authorized 150,000,000 shares; 7,497,433 and 2,450,000 shares issued and outstanding at December 31, 2017 and 2016, respectively	74,974	24,500
Additional paid-in capital	47,812,215	1,147,946
Accumulated deficit	(25,551,652)	(11,357,221)
Total stockholders’ equity (deficit)	22,335,537	(10,184,775)
Total liabilities, redeemable preferred stock and stockholders’ equity (deficit)	24,368,741	2,773,104
Series B Convertible Redeemable Preferred Stock
Current liabilities:
Series B Convertible Redeemable Preferred stock, $0.0001 par value; none and 970,238 shares authorized, issued and outstanding at December 31, 2017 and 2016, respectively	0	8,022,219
Series A Convertible Redeemable Preferred Stock
Current liabilities:
Series B Convertible Redeemable Preferred stock, $0.0001 par value; none and 970,238 shares authorized, issued and outstanding at December 31, 2017 and 2016, respectively	$ 0	$ 4,114,221

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2017	Dec. 31, 2016
Preferred stock, no par value
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	7,497,433	2,450,000
Common stock, shares outstanding	7,497,433	2,450,000
Series B Convertible Redeemable Preferred Stock
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	0	970,238
Preferred stock, shares issued	0	970,238
Preferred stock, shares outstanding	0	970,238
Series A Convertible Redeemable Preferred Stock
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	0	638,416
Preferred stock, shares issued	0	638,416
Preferred stock, shares outstanding	0	638,416

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Operating expenses:
Research and development	$ 8,725,026	$ 5,308,662
General and administrative	5,223,101	1,391,182
Total operating expenses	13,948,127	6,699,844
Loss from operations	(13,948,127)	(6,699,844)
Other income (expense):
Interest income	14,848	282
Interest and other expense	(245,061)	0
Foreign currency transaction loss	(16,091)	0
Total other income (expense), net	(246,304)	282
Net loss	$ (14,194,431)	$ (6,699,562)
Net loss per share - basic and diluted	$ (3.84)	$ (2.73)
Weighted average common shares outstanding - basic and diluted	3,694,388	2,450,000

Consolidated Statements of Chan

Consolidated Statements of Changes in Redeemable Preferred Stock and Stockholders' Equity (Deficit) - USD ($)	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Series B Convertible Redeemable Preferred Stock	Series A Convertible Redeemable Preferred Stock
Redeemable preferred stock, beginning balance at Dec. 31, 2015						$ 4,099,380
Redeemable preferred stock, beginning balance, shares at Dec. 31, 2015						638,416
Issuance of convertible redeemable preferred stock, net of issuance costs					$ 7,994,837
Issuance of convertible redeemable preferred stock, net of issuance costs, shares					970,238
Accretion of issuance costs					$ 27,382	$ 14,841
Redeemable preferred stock, ending balance at Dec. 31, 2016	$ 12,136,440				$ 8,022,219	$ 4,114,221
Redeemable preferred stock, ending balance, shares at Dec. 31, 2016					970,238	638,416
Beginning balance at Dec. 31, 2015	(3,506,793)	$ 24,500	$ 1,126,366	$ (4,657,659)
Beginning balance, shares at Dec. 31, 2015		2,450,000
Conversion of convertible notes and accrued interest into common stock	0
Accretion of issuance costs	(42,223)		(42,223)
Share-based compensation	63,803		63,803
Net loss	(6,699,562)			(6,699,562)
Ending balance at Dec. 31, 2016	$ (10,184,775)	$ 24,500	1,147,946	(11,357,221)
Ending balance, shares at Dec. 31, 2016	2,450,000	2,450,000
Conversion of convertible redeemable preferred stock into common stock					$ (8,149,999)	$ (4,166,164)
Conversion of convertible redeemable preferred stock into common stock, shares					(970,238)	(638,416)
Accretion of issuance costs					$ 127,780	$ 51,943
Redeemable preferred stock, ending balance at Dec. 31, 2017	$ 0				$ 0	$ 0
Redeemable preferred stock, ending balance, shares at Dec. 31, 2017					0	0
Issuance of common stock in connection with merger	6,978,916	$ 7,369	6,971,547
Issuance of common stock in connection with merger, shares		736,950
Conversion of convertible notes and accrued interest into common stock	5,674,452	$ 5,992	5,668,460
Conversion of convertible notes and accrued interest into common stock, shares		599,201
Conversion of convertible redeemable preferred stock into common stock	12,316,163	$ 16,087	12,300,076
Conversion of convertible redeemable preferred stock into common stock, shares		1,608,654
Accretion of issuance costs	(179,723)		(179,723)
Issuance of common stock, net of issuance costs and underwriters discount	21,506,842	$ 21,026	21,485,816
Issuance of common stock, net of issuance costs and underwriters discount, shares		2,102,628
Share-based compensation	418,093		418,093
Net loss	(14,194,431)			(14,194,431)
Ending balance at Dec. 31, 2017	$ 22,335,537	$ 74,974	$ 47,812,215	$ (25,551,652)
Ending balance, shares at Dec. 31, 2017	7,497,433	7,497,433
Issuance of common stock, net of issuance costs, shares		2,102,628

Consolidated Statements of Cha6

Consolidated Statements of Changes in Redeemable Preferred Stock and Stockholders' Equity (Deficit) (Parenthetical)	12 Months Ended
	Dec. 31, 2016USD ($)
Statement Of Stockholders Equity [Abstract]
Issuance of convertible redeemable preferred stock, net of issuance cost	$ 155,162

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net loss	$ (14,194,431)	$ (6,699,562)
Adjustments to reconcile net loss to net cash used in operating activities:
Non-cash interest expense	242,982	0
Share-based compensation	418,093	63,803
Depreciation	3,997	3,532
Loss on disposal of property and equipment	2,078	0
Write-off of deferred financing costs	1,901	67,995
Changes in operating assets and liabilities
Prepaid expenses	(336,834)	(430,571)
Accounts payable	(287,538)	140,011
Accrued expenses	68,144	(102,990)
Other noncurrent assets	(13,648)	0
Net cash used in operating activities	(14,095,256)	(6,957,782)
Cash flows from investing activities:
Cash acquired in Merger, net of payment in lieu of fractional shares	1,030,123	0
Purchase of property and equipment	(62,842)	(1,582)
Net cash provided by (used in) investing activities	967,281	(1,582)
Cash flows from financing activities:
Proceeds from issuance of common stock	21,506,842	0
Proceeds from issuance of Series B Convertible Redeemable Preferred stock, net	0	7,994,837
Deferred financing costs	(68,530)	0
Proceeds from convertible notes payable	5,500,000	0
Net cash provided by financing activities	26,938,312	7,994,837
Net increase in cash and cash equivalents	13,810,337	1,035,473
Cash and cash equivalents, beginning of the year	1,834,018	798,545
Cash and cash equivalents, end of the year	15,644,355	1,834,018
Supplemental cash flow information and non- cash financing transactions:
Cash paid during the year for interest	0	720
Accretion of issuance costs on Series A Convertible Redeemable Preferred stock	51,943	14,841
Accretion of issuance costs on Series B Convertible Redeemable Preferred stock	127,780	27,382
Conversion of Series A Convertible Redeemable Preferred stock to common stock	4,166,164	0
Conversion of Series B Convertible Redeemable Preferred stock to common stock	8,149,999	0
Conversion of convertible notes payable and accrued interest to common stock	5,674,452	0
Issuance of common stock in Merger (Note 1)	$ 6,978,916	$ 0

Nature of Operations and Basis

Nature of Operations and Basis of Presentation	12 Months Ended
	Dec. 31, 2017
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Nature of Operations and Basis of Presentation	1. NATURE OF OPERATIONS AND BASIS OF PRESENTATION Business Acer Therapeutics Inc., a Texas corporation (the “Company”), formerly known as Opexa Therapeutics, Inc. (the “Registrant”), is a pharmaceutical company focused on the acquisition, development, and commercialization of therapies for patients with serious rare and ultra-rare diseases with critical unmet medical need. The Company’s late-stage clinical pipeline includes two candidates for severe genetic disorders: EDSIVO™ (celiprolol) for vascular Ehlers-Danlos syndrome (“vEDS”), and ACER-001 (a fully taste-masked, immediate release formulation of sodium phenylbutyrate) for urea cycle disorders (“UCD”) and Maple Syrup Urine Disease (“MSUD”). There are no FDA-approved drugs for vEDS and MSUD and limited options for UCD, which collectively impact approximately 7,000 patients in the United States. The Company’s products have clinical proof-of-concept and mechanistic differentiation, and it intends to seek approval for them in the U.S. by using the regulatory pathway established under section 505(b)(2) of the Federal Food, Drug, and Cosmetic Act, or FFDCA, that allows an applicant to rely at least in part on third-party data for approval, which may expedite the preparation, submission, and approval of a marketing application. Since its inception, the Company has devoted substantially all of its efforts to business planning, research and development, recruiting management and technical staff, acquiring operating assets and raising capital. The Company has not generated any product revenue to date and may never generate any product revenue in the future. Merger and Reverse Stock Split On September 19, 2017, the Registrant completed its business combination with Acer Therapeutics Inc., a Delaware corporation (“Private Acer”), in accordance with the terms of the Agreement and Plan of Merger and Reorganization, dated as of June 30, 2017, by and among the Registrant, Opexa Merger Sub, Inc. (“Merger Sub”) and Private Acer (the “Merger Agreement”), pursuant to which Merger Sub merged with and into Private Acer, with Private Acer surviving as a wholly-owned subsidiary of the Registrant (the “Merger”). This transaction was approved by the Registrant’s shareholders at a special meeting of its shareholders on September 19, 2017. Also on September 19, 2017, in connection with, and prior to the completion of, the Merger, the Registrant effected a 1-for-10.355527 reverse stock split of its then outstanding common stock (the “Reverse Split”) and immediately following the Merger, the Registrant changed its name to “Acer Therapeutics Inc.” pursuant to amendments to its certificate of formation filed with the Texas Secretary of State on September 19, 2017. All share numbers in this report have been adjusted to reflect the Reverse Split. Following the completion of the Merger, the business conducted by the Registrant became primarily the business conducted by Private Acer, which is a pharmaceutical company that acquires, develops and intends to commercialize therapies for patients with serious rare diseases with critical unmet medical need. Under the terms of the Merger Agreement, the Registrant issued shares of its common stock to Private Acer’s stockholders, at an exchange rate of one share of common stock (after giving effect to the Reverse Split and the conversion of Private Acer’s Series A and Series B preferred stock and convertible debt) in exchange for each share of Private Acer common stock outstanding immediately prior to the Merger. The exchange rate was determined through arm’s length negotiations between the Registrant and Private Acer. The Registrant also assumed all issued and outstanding stock options under the Acer Therapeutics Inc. 2013 Stock Incentive Plan, with such stock options henceforth representing the right to purchase a number of shares of the Registrant’s common stock equal to the number of shares of Private Acer’s common stock previously represented by such stock options. Immediately after the Merger, (i) there were approximately 6.5 million shares of the Registrant’s common stock outstanding; (ii) the former Private Acer stockholders, including investors in the Concurrent Financing (as defined below), owned approximately 89% of the outstanding common stock of the Registrant; and (iii) the Registrant’s shareholders immediately prior to the Merger, whose shares of the Registrant’s common stock remained outstanding after the Merger, owned approximately 11% of the outstanding common stock of the Registrant. The issuance of the shares of the Registrant’s common stock to the former stockholders of Private Acer was registered with the U.S. Securities and Exchange Commission (the “SEC”) on a Registration Statement on Form S-4 (Reg. No. 333-219358). Immediately prior to the Merger, Private Acer issued and sold an aggregate of approximately $15.7 million (inclusive of the conversion of approximately $5.7 million of principal and accrued interest on outstanding convertible promissory notes issued by Private Acer) of shares of Private Acer’s common stock (the “Concurrent Financing”) to certain current stockholders of Private Acer and certain new investors at a per share price of $9.47. The Registrant’s common stock continued to trade on a pre-split basis through the close of business on Wednesday, September 20, 2017, on the Nasdaq Capital Market under the ticker symbol “OPXA.” Commencing with the open of trading on Thursday, September 21, 2017, the post-split shares began trading on the Nasdaq Capital Market under the ticker symbol “ACER.” On September 21, 2017, the Registrant’s Series M Warrants, previously trading through the close of business on Wednesday, September 20, 2017, under the ticker symbol “OPXAW,” commenced trading on the Nasdaq Capital Market, under the ticker symbol “ACERW.” The Registrant’s common stock and Series M Warrants have new CUSIP numbers of 00444P 108 and 00444P 116, respectively. Basis of Presentation Accounting principles generally accepted in the United States require that a company whose security holders retain the majority voting interest in the combined business be treated as the acquirer for financial reporting purposes. Accordingly, the Merger was accounted for as a reverse acquisition whereby Private Acer was treated as the acquirer for accounting and financial reporting purposes. As such, references to the results of operations for the year ended December 31, 2017 include the historical results of Private Acer from January 1, 2017 through September 18, 2017 and include the consolidated results of the combined company from September 19, 2017 through December 31, 2017. References to the results of operations for the year ended December 31, 2016 include only the historical results of Private Acer, except as discussed below. Private Acer was incorporated on December 26, 2013, The accompanying consolidated financial statements for periods prior to August 19, 2016 include the accounts of Private Acer and its wholly-owned subsidiary Anchor. References to the “Company” in these notes refer to (i) Private Acer, for any period prior to March 20, 2015, (ii) Private Acer and its wholly-owned subsidiary Anchor, for the period beginning on March 20, 2015 and ending on August 18, 2016, (iii) Private Acer, for the period beginning on August 19, 2016 and ending on September 18, 2017, and (iv) the Registrant and its wholly-owned subsidiary Private Acer, for the period beginning on September 19, 2017. All intercompany balances and transactions have been eliminated in consolidation. These consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (GAAP). Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification (ASC) and Accounting Standards Update (ASU) of the Financial Accounting Standards Board (FASB). Going Concern Uncertainty The accompanying financial statements have been prepared on a going concern basis, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business. The Company has experienced recurring losses since inception and expects to continue to incur losses for the foreseeable future as it continues its development of, and seeks marketing approvals for, its product candidates. The Company has historically relied on raising capital to finance its operations and plans to raise additional capital through public or private equity and/or debt financings. There is no assurance, however, that the Company will be able to raise sufficient capital to fund its operations on terms that are acceptable, or that its operations will ever be profitable. Based on available resources, the Company believes that its cash and cash equivalents currently on hand are sufficient to fund its anticipated operating and capital requirements through the end of 2018. There is substantial doubt about the Company’s ability to continue as a going concern within one year after the date that the accompanying financial statements are issued. These financial statements do not include any adjustments relating to the recoverability of recorded asset amounts that might be necessary as a result of the above uncertainty.

Significant Accounting Polices

Significant Accounting Polices	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Significant Accounting Polices	2. SIGNIFICANT ACCOUNTING POLICIES A summary of the significant accounting policies followed by the Company in the preparation of the accompanying consolidated financial statements follows: Use of Estimates The Company’s accounting principles require management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of assets and liabilities at the date of the financial statements and reported amounts of revenues and expenses during the reporting period. Estimates having relatively higher significance include the accounting for acquisitions, stock-based compensation, and income taxes. Actual results could differ from those estimates and changes in estimates may occur. Cash and Cash Equivalents The Company considers all highly liquid investments with maturities of three months or less at the date of purchase to be cash equivalents. Research and Development Expenses Costs incurred for research and development are expensed as incurred. Business Combinations Assets acquired and liabilities assumed as part of a business acquisition are generally recorded at their fair value at the date of acquisition. The excess of purchase price over the fair value of assets acquired and liabilities assumed is recorded as goodwill. Determining fair value of identifiable assets, particularly intangibles, and liabilities acquired also requires management to make estimates, which are based on all available information and in some cases assumptions with respect to the timing and amount of future revenues and expenses associated with an asset. Accounting for business acquisitions may require management to make judgments and estimates as to the fair value of consideration transferred. This judgment and determination may affect the amount of consideration paid that is allocable to assets and liabilities acquired in the business purchase transaction. Share-Based Compensation The Company records share-based payments at fair value. The measurement date for compensation expense related to employee awards is generally the date of the grant. The measurement date for compensation expense related to nonemployee awards is generally the date that the performance of the awards is completed and, until such time, the fair value of the awards is remeasured at the end of each reporting period. Accordingly, the ultimate expense is not fixed until such awards are vested. The fair value of awards, net of expected forfeitures, is recognized as an expense in the statement of operations over the requisite service period, which is generally the vesting period. The fair value of options is calculated using the Black-Scholes option pricing model. This option valuation model requires the use of assumptions including, among others, the volatility of stock price, the expected term of the option, and the risk-free interest rate. The following assumptions were used to estimate the fair value of stock options granted using the Black-Scholes option pricing model: 2017 2016 Risk-free interest rate 1.93% 1.73% Expected life (years) 6 5 Volatility 60% 60% Dividend rate 0% 0% Due to its limited operating history and a limited trading history of its common stock, the Company estimates the volatility of its stock in consideration of a number of factors including the volatility of comparable public companies. The expected term of a stock option granted to employees and directors (including non-employee directors) is based on the average of the contractual term (generally 10 years) and the vesting period. For other non-employee options, the expected term is the contractual term. The assumed dividend yield is based upon the Company’s expectation of not paying dividends in the foreseeable future. The Company recognizes forfeitures related to employee share-based payments as they occur. The risk-free rate for periods within the expected life of the option is based upon the U.S. Treasury yield curve in effect at the time of grant. Prior to the Merger, the fair value of the common stock for the purposes of determining the exercise price of stock options was determined by the Board of Directors after considering a broad range of factors, including the results of a third-party valuation. Subsequent to the Merger, option awards are granted at an exercise price equal to the closing market price of the Company’s common stock on the Nasdaq Capital Market on the date of grant. In-process Research and Development In-process research and development (“IPRD”) represents the value of the three G-protein-coupled receptors (“GPCR”) targets (the “Targets”) from the GPCR Target pools of Anchor to which the Company obtained the rights in its March 20, 2015, acquisition of Anchor. IPRD was recorded at fair value and is an indefinite-lived intangible asset. The Company reviews IPRD annually to determine if any adverse conditions exist or a change in circumstances has occurred that would indicate impairment or a change in the remaining useful life of the asset. There were no triggering events or circumstances that would indicate IPRD is impaired as of December 31, 2017. Goodwill Goodwill represents the excess of cost over fair value of net assets acquired. The Company evaluates the recoverability of goodwill annually or more frequently if events or changes in circumstances indicate that the carrying value of goodwill might be impaired. The Company first assesses qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying value. This step serves as the basis for determining whether it is necessary to perform the two-step goodwill impairment test. If the Company determines it is more likely than not that the fair value of a reporting unit is less than its carrying value, then it will perform the two-step test. The two-step test first compares the fair value of the reporting unit to its carrying value. If the fair value exceeds the carrying value, no impairment exists, and the second step is not performed. If the fair value of the reporting unit is less than its carrying value, an impairment loss is recorded as part of the second step of the test, to the extent that the implied fair value of the reporting unit goodwill is less than the carrying value. The Company performed a qualitative analysis of goodwill in the fourth quarter of 2017, in which management concluded that it is more likely than not that the fair value of the reporting unit is greater than its carrying amount. Income Taxes The Company is primarily subject to U.S. Federal and Massachusetts state income taxes. As per statute, the Company’s tax returns since incorporation in 2013 are open to tax examinations by U.S. Federal and state tax authorities. For federal and state income taxes, deferred tax assets and liabilities are recognized based upon temporary differences between the financial statement and the tax basis of assets and liabilities. Deferred income taxes are based upon prescribed rates and enacted laws applicable to periods in which differences are expected to reverse. A valuation allowance is recorded when it is more likely than not that some portion or all of the deferred tax assets will not be realized. Accordingly, the Company provides a valuation allowance, if necessary, to reduce deferred tax assets to amounts that are realizable. The tax positions taken or expected to be taken in the course of preparing the Company tax returns are required to be evaluated to determine whether the tax positions are “more-likely-than-not” of being sustained by the applicable tax authority. Tax positions not deemed to meet a more-likely-than-not threshold would be recorded as a tax expense in the current year. There were no uncertain tax positions that require accrual or disclosure in the consolidated financial statements as of December 31, 2017, and 2016. The Company’s policy is to recognize interest and penalties related to income tax, if any, in income tax expense. As of December 31, 2017, and 2016, the Company has no accruals for interest or penalties related to income tax matters. Basic and Diluted Net Loss per Common Share Basic and diluted net loss per common share is computed by dividing net loss in each period by the weighted average number of shares of common stock outstanding during such period. For the periods presented, common stock equivalents, consisting of options, convertible redeemable preferred stock and warrants, were not included in the calculation of the diluted loss per share because to do so would be anti-dilutive. Segment Information Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision maker, or decision-making group, in deciding how to allocate resources and in assessing performance. The Company views its operations and manages its business in one operating segment, which is the business of a pharmaceutical company focused on the acquisition, development, and commercialization of therapies for patients with serious rare and ultra-rare diseases with critical unmet medical need. Recently Adopted Accounting Pronouncements In March 2016, the FASB issued ASU No. 2016-09, Improvements to Employee Share-Based Payment Accounting Recently Issued Accounting Pronouncements In January 2017, the FASB issued ASU No. 2017-04, Intangibles – Goodwill and Other

Purchase Accounting

Purchase Accounting	12 Months Ended
	Dec. 31, 2017
Business Combinations [Abstract]
Purchase Accounting	3. PURCHASE ACCOUNTING Private Acer recorded $272,315 of goodwill in connection with its acquisition of Anchor in 2015. Under the merger agreement with Anchor, if the pepducin business was not sold within 12 months of the merger date, the pepducin business reverted to the holders of Anchor’s equity immediately prior to the merger. The sale did not occur within this period. The reversion was accomplished through a Pepducin Transfer Agreement, entered into on August 19, 2016, pursuant to which the Company transferred all the outstanding stock of Anchor to Teserx, Inc., a new entity designated by the stockholders’ representative for the benefit of holders of Anchor’s equity immediately prior to the merger. The Company retained the exclusive rights to the two pepducin drug targets and obtained ownership to the third. No gain or loss was recorded by the Company when the pepducin business reverted back to the prior holders of Anchor’s equity and the Company has no continuing involvement in the pepducin business or with Teserx, Inc. Merger with Opexa Therapeutics, Inc. The Merger was accounted for using the purchase method of accounting as a reverse acquisition. In a reverse acquisition, the post-acquisition net assets of the surviving combined company includes the historical cost basis of the net assets of the accounting acquirer (Private Acer) plus the fair value of the net assets of the accounting acquiree (the Registrant). Further, under the purchase method, the purchase price is allocated to the assets acquired, liabilities assumed, and identifiable intangible assets based on their estimated fair values, with the remaining excess purchase price over net assets acquired allocated to goodwill. The fair value of the consideration transferred in the Merger was $7,007,069 and was calculated as the number of shares of common stock that Private Acer issued (adjusted for the exchange ratio) in order for the Registrant’s shareholders to hold an 11% equity interest in the combined company post-acquisition, multiplied by the estimated fair value of Private Acer’s common stock on the acquisition date. The estimated fair value of Private Acer’s common stock was based on the offering price of the common stock sold in the Concurrent Financing that was both completed concurrently with and conditioned upon the closing of the Merger. This price was determined to be the best indication of fair value on that date since the price was based on an arm’s length negotiation with a group consisting of both new and existing investors of Private Acer that had been advised of the pending Merger and assumed similar liquidity risk as those investors holding the majority of shares being valued as purchase consideration. The following table summarizes the Company’s determination of fair values of the assets acquired and the liabilities assumed as of the date of acquisition. As of December 31, 2017, the Company has determined that no impairment charges were necessary. Consideration - issuance of securities and cash paid for fractional shares $ 7,007,069 Assets acquired and liabilities assumed: Cash $ 1,058,276 Other assets 5,000 Accrued liabilities (1,431,159 ) Goodwill 7,374,952 Total purchase price $ 7,007,069 The Company determined that the acquired legacy technology of the Registrant had no value as of the date of the acquisition. Goodwill represents the excess of the purchase price (consideration paid plus net liabilities assumed) of an acquired business over the fair value of the underlying net tangible and intangible assets. Goodwill includes the value of the Registrant’s standing as a public entity. None of the goodwill associated with the Merger is deductible for income tax purposes. All of the goodwill will be allocated to the Company’s single reportable segment. There were no changes in goodwill during the year ended December 31, 2017, after the initial purchase accounting. Unaudited pro forma operating results, assuming the Merger occurred as of January 1, 2016, are as follows: Years Ended December 31, 2017 2016 Net loss $ (17,733,252 ) $ (15,993,790 ) Net loss per share - basic and diluted $ (2.73 ) $ (2.73 )

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2017
Property And Equipment [Abstract]
Property and Equipment	4. PROPERTY AND EQUIPMENT Property and equipment consisted of the following at December 31, 2017 and December 31, 2016: December 31, 2017 December 31, 2016 Computer hardware and software $ 16,555 $ 10,862 Leasehold improvements 7,968 — Furniture & fixtures 42,503 — Less accumulated depreciation (4,042 ) (4,645 ) $ 62,984 $ 6,217 Property and equipment are stated on the basis of historical cost less accumulated depreciation. Depreciation is provided using the straight-line method over the estimated useful lives of the assets. Major renewals and improvements are capitalized, while minor replacements, maintenance and repairs are charged to current operations. Impairment losses are recorded on long-lived assets used in operations when indicators of impairment are present and the undiscounted cash flows estimated to be generated by those assets are less than the assets’ carrying amount. Computer hardware and software are depreciated over an estimated useful life of 3 years, tenant improvements are depreciated over 1 year through the end of the current lease arrangement, and office furniture is depreciated over an estimated useful life of 7 years.

Accrued Expenses

Accrued Expenses	12 Months Ended
	Dec. 31, 2017
Accounts Payable And Accrued Liabilities Current [Abstract]
Accrued Expenses	5. ACCRUED EXPENSES Accrued expenses consisted of the following at December 31, 2017, and December 31, 2016: December 31, 2017 December 31, 2016 Accrued legal $ 174,592 $ 21,477 Accrued pre-commercial costs 341,159 — Accrued consulting 102,156 13,105 Accrued audit and tax 111,250 39,820 Accrued license fees 817,578 205,444 Accrued contract manufacturing 218,108 126,700 Accrued contract research 99,140 16,800 Accrued miscellaneous expenses 73,348 14,682 $ 1,937,331 $ 438,028

Convertible Notes Payable

Convertible Notes Payable	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Convertible Notes Payable	6. CONVERTIBLE NOTES PAYABLE On March 22, 2017, Private Acer issued senior secured convertible notes payable (the “2017 Notes”) to existing investors and a vendor in the aggregate principal amount of $3,125,000. The 2017 Notes accrued interest at 10% per annum and matured on the earlier of (i) March 22, 2018 (the “Maturity Date”) or (ii) upon a Change in Control of Private Acer, as defined therein. On May 31, 2017, Private Acer issued additional 2017 Notes to existing investors and a vendor in the aggregate principal amount of $2,375,000. The 2017 Notes were convertible into common stock upon a Qualified Financing (as defined therein), a Change in Control, or an optional conversion by the holder. Conversion upon a Qualified Financing was at a price per share equal to the price per share paid for the shares sold in the Qualified Financing less a discount of: (i) 0%, if a Qualified Financing occurred on or before June 30, 2017; (ii) 10%, if a Qualified Financing occurred after June 30, 2017, but on or before September 1, 2017; or (iii) 20%, if a Qualified Financing occurred after September 1, 2017. Conversion upon a Change in Control was at the discretion of the holder such that Private Acer would pay each holder the outstanding balance on their respective note or the note would be converted at a price per share equal to the lesser of $16.57 and the price per share of common stock paid to the holders of the common stock in such Change in Control. Conversion under an optional conversion by the holder was at a price per share of $16.57 based on the outstanding balance of the note. Upon the issuance of the 2017 Notes, the Company evaluated all terms of the 2017 Notes, including the Change in Control provision, to identify any embedded features that required bifurcation and recording as derivative instruments. The Company determined that there were no such features requiring separate accounting. In connection with the 2017 Notes, the Company incurred debt issuance costs of $68,530 and recorded them as a debt discount. During the year ended December 31, 2017, the Company recognized $242,982 of interest expense, which includes $68,530 in amortization of debt discount and $174,452 of accrued interest on the 2017 Notes. The principal of $5,500,000 and accrued interest of $174,452 on the 2017 Notes converted into 599,201 fully-paid shares of common stock at the time of the Merger described in Note 1, with no discount on the conversion.

Commitments

Commitments	12 Months Ended
	Dec. 31, 2017
Commitments And Contingencies [Abstract]
Commitments	7. COMMITMENTS License Agreements In August 2016, Private Acer signed an agreement with Assistance Publique—Hôpitaux de Paris, Hôpital Européen Georges Pompidou, or AP-HP (via its Department of Clinical Research and Development) granting the Company exclusive worldwide rights to access and use data from a randomized controlled clinical study of celiprolol. The Company will use this pivotal clinical data to support an NDA regulatory filing for its lead product, celiprolol, for the treatment of vEDS. The agreement requires the Company to make certain upfront payments to AP-HP, as well as reimburse certain costs, and make payments upon achievement of defined milestones and payment of royalties on net sales of celiprolol over the royalty term. In April 2014, Private Acer obtained exclusive rights to intellectual property relating to ACER-001 and preclinical and clinical data, through an exclusive license agreement with Baylor College of Medicine (“BCM”). Under the terms of the agreement, as amended, the Company has worldwide exclusive rights to develop, manufacture, use, sell and import Licensed Products as defined in the agreement. The license agreement requires the Company to make certain upfront and annual payments to BCM, as well as reimburse certain legal costs, and make payments upon achievement of defined milestones and payment of royalties on net sales of any developed product over the royalty term. Litigation From time to time, the Company or its subsidiaries may become involved in litigation or proceedings relating to claims arising from the ordinary course of business. On September 27, 2017, Piper Jaffray & Co. filed a lawsuit against Private Acer, Piper Jaffray & Co. v. Acer Therapeutics Inc., Index No. 656055/2017, in the Supreme Court of the State of New York, County of New York. The complaint alleges that Private Acer breached its obligations to Piper Jaffray & Co. pursuant to an August 30, 2016 engagement letter between the parties and an April 28, 2017 addendum thereto by failing to pay Piper Jaffray & Co. (i) a fee of $1,097,207 in connection with the financing which closed on September 19, 2017 for aggregate consideration of approximately $15.7 million (including the conversion of the 2017 Notes described in Note 6) and (ii) $67,496 in reimbursement for expenses incurred by Piper Jaffray & Co. pursuant to the engagement letter. On November 10, 2017, Private Acer filed an answer and counterclaim in the lawsuit, denying Piper Jaffray & Co.’s breach of contract allegation, asserting several defenses, and bringing several counterclaims, including claims for breach of contract and breach of the duty of good faith and fair dealing. Piper Jaffray & Co. filed a reply to the counterclaims denying the essential allegations, and discovery has commenced. The Company has not recorded a liability as of December 31, 2017, because a potential loss is not probable or reasonably estimable given the preliminary nature of the proceedings.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Stockholders' Equity	8. STOCKHOLDERS’ EQUITY Immediately prior to the consummation of the Merger described in Note 1, (i) Private Acer’s Series A Convertible Redeemable Preferred stock and Series B Convertible Redeemable Preferred stock were converted into 638,416 and 970,238 shares of common stock, respectively, (ii) Private Acer’s 2017 Notes and accrued interest totaling $5,674,452 were converted into 599,201 shares of common stock, and (iii) 1,055,961 shares of common stock were sold by Private Acer for $9.47 per share generating $10,000,000 of gross proceeds. At the closing of the Merger, 736,950 shares of common stock were held by existing shareholders of the Registrant. On December 14, 2017, the Company closed on an underwritten public offering of its common stock of 916,667 shares at a price of $12.00 per share. The gross proceeds were $11.0 million, before deducting the underwriting discount and other estimated offering expenses. Subsequently, on December 27, 2017, the Company sold an additional 130,000 shares in connection with the over-allotment option granted to the underwriters, for an additional $1.6 million of gross proceeds, before deducting the underwriting discount. The total amount of underwriting discount and other offering costs deducted from gross proceeds was $1.1 million. 2010 Stock Incentive Plan The Company’s 2010 Stock Incentive Plan, as amended and restated (the “2010 Plan”), provides for the grant of up to 470,170 shares of common stock as incentive or non-qualified stock options, stock appreciation rights, restricted stock units and/or restricted common stock to employees, officers, directors, consultants and advisers. The 2010 Plan was amended to increase the shares reserved for issuance from 113,465 to 470,170 shares and such amendment was approved by the Registrant’s shareholders on September 19, 2017. The Board of Directors or the Compensation Committee, as applicable, administers the 2010 Plan and has discretion to determine the recipients, the number and types of equity awards to be granted and the terms and conditions of the equity awards, including the period of their exercisability and vesting. Subject to a limitation on repricing without shareholder approval, the Board or the Compensation Committee, as applicable, may also determine the exercise price of options granted under the 2010 Plan. Option awards are generally granted with an exercise price equal to the fair value of the common stock at the date of grant and have contractual terms of 10 years. Stock options granted to executive officers and employees vest over a four-year period, with 25% vesting on the one-year anniversary of the grant date and the remaining 75% vesting quarterly over the remaining three years, assuming continued service, and with vesting acceleration in full immediately prior to a change in control. Stock options granted to outside non-employee directors vest either (a) in full on the one-year anniversary of the grant date, assuming continued service, for awards to continuing directors, with vesting acceleration in full immediately prior to a change in control, or (b) quarterly over a three-year period, assuming continued service, for awards to new directors, with vesting acceleration in full immediately prior to a change in control. All outstanding and unexercised equity awards (representing 22,061 underlying shares) under the 2010 Plan were canceled in connection with the Merger. At December 31, 2017, 159,572 shares of common stock remained available for the grant of future awards under the 2010 Plan. 2013 Stock Incentive Plan Private Acer’s 2013 Stock Incentive Plan, as amended (the “2013 Plan”), which was assumed by the Company in connection with the Merger, provides for the issuance of up to 165,000 shares of common stock as incentive or non-qualified stock options and/or restricted common stock to employees, officers, directors, consultants and advisers. Option awards are generally granted with an exercise price equal to the fair value of the common stock at the date of grant and have contractual terms of 10 years. At December 31, 2017, all shares available under the 2013 Plan were subject to outstanding equity awards, and the Company does not intend to make any new awards under the 2013 Plan. A summary of option activity under the 2010 Plan and the 2013 Plan for the year ended December 31, 2017, is as follows: Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (Years) Aggregate Intrinsic Value Options outstanding at December 31, 2016 122,000 $ 2.55 8.8 Granted 347,225 $ 14.10 Exercised — $ — Cancelled/forfeited (5,625 ) $ 2.55 Options outstanding at December 31, 2017 463,600 $ 11.23 9.5 $ 1,752,470 Options exercisable at December 31, 2017 139,634 $ 3.49 8.9 $ 1,448,223 At December 31, 2017, there was approximately $2.5 million of unrecognized compensation expense related to the share-based compensation arrangements granted under both plans and the average remaining vesting period is 3.3 years. The weighted average grant date fair value of options granted during the year ended December 31, 2017 and 2016, was $8.25 and $1.32, respectively. The amount of stock-based compensation expense recorded to general and administrative, and research and development was approximately $111,000 and $307,000, respectively, for the year ended December 31, 2017. Warrants A summary of warrant activity for the year ended December 31, 2017, Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contract Term Intrinsic Value Assumed in the Merger at September 19, 2017 317,630 $ 123.61 0.54 — Outstanding and exercisable at December 31, 2017 317,630 $ 123.61 0.29 —

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	9. INCOME TAXES There was no provision for income taxes for the years ended December 31, 2017, and 2016, due to the Company’s operating losses and a full valuation allowance on deferred tax assets. Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of the Company’s deferred tax assets and liabilities are as follows: December 31, 2017 2016 Deferred tax assets: Net operating loss carry forwards $ 1,843,000 $ 537,000 Capitalized research and development costs 12,177,000 2,532,000 Accrued liabilities 25,000 15,000 Tax credit carryforwards 3,286,000 1,683,000 Stock-based compensation 116,000 38,000 Total deferred tax assets 17,447,000 4,805,000 Valuation allowance (17,444,000 ) (4,805,000 ) Net deferred tax assets 3,000 — Deferred tax liabilities (3,000 ) — $ — $ — A reconciliation of the U.S. federal statutory tax rate to the effective tax rate is as follows: December 31, 2017 2016 Federal statutory rate 34.0 % 34.0 % R&D and Orphan drug credits 7.6 % 15.8 % State income tax, net of federal tax benefit -0.2 % -17.7 % Valuation allowance 18.2 % 137.1 % Reduction in tax attributed related to deconsolidation of subsidiary 0.0 % -169.0 % Tax reform impact -57.8 % 0.0 % Other, net -1.8 % -0.2 % Effective tax rate 0.0 % 0.0 % The increase in deferred tax assets in 2017 is a result of the Merger (see Note 3). Management currently believes that it is more likely than not that the deferred tax assets relating to the loss carryforwards and other temporary differences will not be realized in the future. Through December 31, 2017, for income tax reporting purposes, the Company had U.S. Federal and state net operating loss carryforwards of approximately $8.4 million (corresponding to $1.8 million on a tax effected basis in the table above), that can be carried forward and offset against taxable income. Federal and Massachusetts net operating losses can be carried forward for 20 years and begin to expire in 2024. Utilization of net operating losses may be subject to substantial annual limitations due to the “change in ownership” provisions of the Internal Revenue Code of 1986, and similar state provisions. The annual limitations may result in the expiration of net operating losses before utilization. On December 22, 2017, The Tax Cuts and Jobs Act (the “Act”) was enacted. The Act significantly revised the U.S. corporate income tax law by lowering the corporate Federal income tax rate from 35% to 21%. As of December 31, 2017, the Company has assessed the effects of the corporate rate reduction on its existing deferred tax balances which resulted in a $8.2 million reduction in the deferred tax assets. Since the Company maintains a full valuation allowance on its deferred tax assets, a corresponding reduction in the valuation allowance equal to the effect of the rate reduction on the ending deferred tax asset was also reflected. In addition to the rate reduction, the Act also requires companies with foreign subsidiaries to pay a one-time transition tax on earnings that were previously tax deferred. As of December 31, 2017, the Company does not maintain any foreign subsidiaries and does not have previously deferred foreign earnings subject to the transition tax.

Net Loss Per Share

Net Loss Per Share	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Net Loss Per Share	10. NET LOSS PER SHARE Basic net loss per share is computed by dividing the net loss by the weighted-average number of common shares outstanding. Diluted net loss per share is computed similarly to basic net loss per share except that the denominator is increased to include the number of additional common shares that would have been outstanding if the potential common shares had been issued and if the additional common shares were dilutive. Diluted net loss per share is the same as basic net loss per common share, since the effects of potentially dilutive securities are antidilutive. As of December 31, 2017, and 2016, the number of shares of common stock underlying potentially dilutive securities include: December 31, 2017 2016 Convertible redeemable preferred stock — 638,416 Warrants 317,630 — Options to purchase common stock 463,600 122,000 Total 781,230 760,416

Significant Accounting Polices

Significant Accounting Polices (Policies)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Use of Estimates	Use of Estimates The Company’s accounting principles require management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of assets and liabilities at the date of the financial statements and reported amounts of revenues and expenses during the reporting period. Estimates having relatively higher significance include the accounting for acquisitions, stock-based compensation, and income taxes. Actual results could differ from those estimates and changes in estimates may occur.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments with maturities of three months or less at the date of purchase to be cash equivalents.
Research and Development Expenses	Research and Development Expenses Costs incurred for research and development are expensed as incurred.
Business Combinations	Business Combinations Assets acquired and liabilities assumed as part of a business acquisition are generally recorded at their fair value at the date of acquisition. The excess of purchase price over the fair value of assets acquired and liabilities assumed is recorded as goodwill. Determining fair value of identifiable assets, particularly intangibles, and liabilities acquired also requires management to make estimates, which are based on all available information and in some cases assumptions with respect to the timing and amount of future revenues and expenses associated with an asset. Accounting for business acquisitions may require management to make judgments and estimates as to the fair value of consideration transferred. This judgment and determination may affect the amount of consideration paid that is allocable to assets and liabilities acquired in the business purchase transaction.
Share-Based Compensation	Share-Based Compensation The Company records share-based payments at fair value. The measurement date for compensation expense related to employee awards is generally the date of the grant. The measurement date for compensation expense related to nonemployee awards is generally the date that the performance of the awards is completed and, until such time, the fair value of the awards is remeasured at the end of each reporting period. Accordingly, the ultimate expense is not fixed until such awards are vested. The fair value of awards, net of expected forfeitures, is recognized as an expense in the statement of operations over the requisite service period, which is generally the vesting period. The fair value of options is calculated using the Black-Scholes option pricing model. This option valuation model requires the use of assumptions including, among others, the volatility of stock price, the expected term of the option, and the risk-free interest rate. The following assumptions were used to estimate the fair value of stock options granted using the Black-Scholes option pricing model: 2017 2016 Risk-free interest rate 1.93% 1.73% Expected life (years) 6 5 Volatility 60% 60% Dividend rate 0% 0% Due to its limited operating history and a limited trading history of its common stock, the Company estimates the volatility of its stock in consideration of a number of factors including the volatility of comparable public companies. The expected term of a stock option granted to employees and directors (including non-employee directors) is based on the average of the contractual term (generally 10 years) and the vesting period. For other non-employee options, the expected term is the contractual term. The assumed dividend yield is based upon the Company’s expectation of not paying dividends in the foreseeable future. The Company recognizes forfeitures related to employee share-based payments as they occur. The risk-free rate for periods within the expected life of the option is based upon the U.S. Treasury yield curve in effect at the time of grant. Prior to the Merger, the fair value of the common stock for the purposes of determining the exercise price of stock options was determined by the Board of Directors after considering a broad range of factors, including the results of a third-party valuation. Subsequent to the Merger, option awards are granted at an exercise price equal to the closing market price of the Company’s common stock on the Nasdaq Capital Market on the date of grant.
In-process Research and Development	In-process Research and Development In-process research and development (“IPRD”) represents the value of the three G-protein-coupled receptors (“GPCR”) targets (the “Targets”) from the GPCR Target pools of Anchor to which the Company obtained the rights in its March 20, 2015, acquisition of Anchor. IPRD was recorded at fair value and is an indefinite-lived intangible asset. The Company reviews IPRD annually to determine if any adverse conditions exist or a change in circumstances has occurred that would indicate impairment or a change in the remaining useful life of the asset. There were no triggering events or circumstances that would indicate IPRD is impaired as of December 31, 2017.
Goodwill	Goodwill Goodwill represents the excess of cost over fair value of net assets acquired. The Company evaluates the recoverability of goodwill annually or more frequently if events or changes in circumstances indicate that the carrying value of goodwill might be impaired. The Company first assesses qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying value. This step serves as the basis for determining whether it is necessary to perform the two-step goodwill impairment test. If the Company determines it is more likely than not that the fair value of a reporting unit is less than its carrying value, then it will perform the two-step test. The two-step test first compares the fair value of the reporting unit to its carrying value. If the fair value exceeds the carrying value, no impairment exists, and the second step is not performed. If the fair value of the reporting unit is less than its carrying value, an impairment loss is recorded as part of the second step of the test, to the extent that the implied fair value of the reporting unit goodwill is less than the carrying value. The Company performed a qualitative analysis of goodwill in the fourth quarter of 2017, in which management concluded that it is more likely than not that the fair value of the reporting unit is greater than its carrying amount.
Income Taxes	Income Taxes The Company is primarily subject to U.S. Federal and Massachusetts state income taxes. As per statute, the Company’s tax returns since incorporation in 2013 are open to tax examinations by U.S. Federal and state tax authorities. For federal and state income taxes, deferred tax assets and liabilities are recognized based upon temporary differences between the financial statement and the tax basis of assets and liabilities. Deferred income taxes are based upon prescribed rates and enacted laws applicable to periods in which differences are expected to reverse. A valuation allowance is recorded when it is more likely than not that some portion or all of the deferred tax assets will not be realized. Accordingly, the Company provides a valuation allowance, if necessary, to reduce deferred tax assets to amounts that are realizable. The tax positions taken or expected to be taken in the course of preparing the Company tax returns are required to be evaluated to determine whether the tax positions are “more-likely-than-not” of being sustained by the applicable tax authority. Tax positions not deemed to meet a more-likely-than-not threshold would be recorded as a tax expense in the current year. There were no uncertain tax positions that require accrual or disclosure in the consolidated financial statements as of December 31, 2017, and 2016. The Company’s policy is to recognize interest and penalties related to income tax, if any, in income tax expense. As of December 31, 2017, and 2016, the Company has no accruals for interest or penalties related to income tax matters.
Basic and Diluted Net Loss per Common Share	Basic and Diluted Net Loss per Common Share Basic and diluted net loss per common share is computed by dividing net loss in each period by the weighted average number of shares of common stock outstanding during such period. For the periods presented, common stock equivalents, consisting of options, convertible redeemable preferred stock and warrants, were not included in the calculation of the diluted loss per share because to do so would be anti-dilutive.
Segment Information	Segment Information Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision maker, or decision-making group, in deciding how to allocate resources and in assessing performance. The Company views its operations and manages its business in one operating segment, which is the business of a pharmaceutical company focused on the acquisition, development, and commercialization of therapies for patients with serious rare and ultra-rare diseases with critical unmet medical need.
Recently Adopted and Issued Accounting Pronouncements	Recently Adopted Accounting Pronouncements In March 2016, the FASB issued ASU No. 2016-09, Improvements to Employee Share-Based Payment Accounting Recently Issued Accounting Pronouncements In January 2017, the FASB issued ASU No. 2017-04, Intangibles – Goodwill and Other

Significant Accounting Police19

Significant Accounting Polices (Tables)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Schedule of Estimate Fair Value of Stock Options Granted	The following assumptions were used to estimate the fair value of stock options granted using the Black-Scholes option pricing model: 2017 2016 Risk-free interest rate 1.93% 1.73% Expected life (years) 6 5 Volatility 60% 60% Dividend rate 0% 0%

Purchase Accounting (Tables)

Purchase Accounting (Tables)	12 Months Ended
	Dec. 31, 2017
Business Combinations [Abstract]
Fair Values of Assets Acquired and Liabilities Assumed	The following table summarizes the Company’s determination of fair values of the assets acquired and the liabilities assumed as of the date of acquisition. As of December 31, 2017, the Company has determined that no impairment charges were necessary. Consideration - issuance of securities and cash paid for fractional shares $ 7,007,069 Assets acquired and liabilities assumed: Cash $ 1,058,276 Other assets 5,000 Accrued liabilities (1,431,159 ) Goodwill 7,374,952 Total purchase price $ 7,007,069
Unaudited Pro Forma Operating Results	Unaudited pro forma operating results, assuming the Merger occurred as of January 1, 2016, are as follows: Years Ended December 31, 2017 2016 Net loss $ (17,733,252 ) $ (15,993,790 ) Net loss per share - basic and diluted $ (2.73 ) $ (2.73 )

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2017
Property And Equipment Tables [Abstract]
Property and Equipment	Property and equipment consisted of the following at December 31, 2017 and December 31, 2016: December 31, 2017 December 31, 2016 Computer hardware and software $ 16,555 $ 10,862 Leasehold improvements 7,968 — Furniture & fixtures 42,503 — Less accumulated depreciation (4,042 ) (4,645 ) $ 62,984 $ 6,217

Accrued Expenses (Tables)

Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2017
Accounts Payable And Accrued Liabilities Current [Abstract]
Schedule of Accrued Expenses	Accrued expenses consisted of the following at December 31, 2017, and December 31, 2016: December 31, 2017 December 31, 2016 Accrued legal $ 174,592 $ 21,477 Accrued pre-commercial costs 341,159 — Accrued consulting 102,156 13,105 Accrued audit and tax 111,250 39,820 Accrued license fees 817,578 205,444 Accrued contract manufacturing 218,108 126,700 Accrued contract research 99,140 16,800 Accrued miscellaneous expenses 73,348 14,682 $ 1,937,331 $ 438,028

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Summary of Option Activity under 2010 Plan and 2013 Plan	A summary of option activity under the 2010 Plan and the 2013 Plan for the year ended December 31, 2017, is as follows: Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (Years) Aggregate Intrinsic Value Options outstanding at December 31, 2016 122,000 $ 2.55 8.8 Granted 347,225 $ 14.10 Exercised — $ — Cancelled/forfeited (5,625 ) $ 2.55 Options outstanding at December 31, 2017 463,600 $ 11.23 9.5 $ 1,752,470 Options exercisable at December 31, 2017 139,634 $ 3.49 8.9 $ 1,448,223
Summary of Warrant Activity	A summary of warrant activity for the year ended December 31, 2017, Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contract Term Intrinsic Value Assumed in the Merger at September 19, 2017 317,630 $ 123.61 0.54 — Outstanding and exercisable at December 31, 2017 317,630 $ 123.61 0.29 —

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Taxes Tables [Abstract]
Schedule of Components of Deferred Tax Assets and Liabilities	Significant components of the Company’s deferred tax assets and liabilities are as follows: December 31, 2017 2016 Deferred tax assets: Net operating loss carry forwards $ 1,843,000 $ 537,000 Capitalized research and development costs 12,177,000 2,532,000 Accrued liabilities 25,000 15,000 Tax credit carryforwards 3,286,000 1,683,000 Stock-based compensation 116,000 38,000 Total deferred tax assets 17,447,000 4,805,000 Valuation allowance (17,444,000 ) (4,805,000 ) Net deferred tax assets 3,000 — Deferred tax liabilities (3,000 ) — $ — $ —
Schedule of Reconciliation of Effective Income Tax Rate	A reconciliation of the U.S. federal statutory tax rate to the effective tax rate is as follows: December 31, 2017 2016 Federal statutory rate 34.0 % 34.0 % R&D and Orphan drug credits 7.6 % 15.8 % State income tax, net of federal tax benefit -0.2 % -17.7 % Valuation allowance 18.2 % 137.1 % Reduction in tax attributed related to deconsolidation of subsidiary 0.0 % -169.0 % Tax reform impact -57.8 % 0.0 % Other, net -1.8 % -0.2 % Effective tax rate 0.0 % 0.0 %

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Common Stock Underlying Potentially Dilutive Securities	As of December 31, 2017, and 2016, the number of shares of common stock underlying potentially dilutive securities include: December 31, 2017 2016 Convertible redeemable preferred stock — 638,416 Warrants 317,630 — Options to purchase common stock 463,600 122,000 Total 781,230 760,416

Nature of Operations and Basi26

Nature of Operations and Basis of Presentation - Additional Information (Details)	Sep. 19, 2017$ / sharesshares	Sep. 18, 2017USD ($)$ / shares	Dec. 31, 2017USD ($)Patientshares	Dec. 31, 2016shares
Organization Consolidation and Presentation of Financial Statement [Line Items]
Number of patients unapproved | Patient			7,000
Common stock, shares outstanding | shares	6,500,000		7,497,433	2,450,000
Aggregate common stock issued and sold prior to merger			$ 21,506,842
Shares issued price per share | $ / shares	$ 9.47
Private Acer
Organization Consolidation and Presentation of Financial Statement [Line Items]
Shares issued in exchange of common stock upon merger	1.00%
Percentage of outstanding common stock owned by acquirer's shareholders	89.00%
Percentage of outstanding common stock owned by registrant's shareholders	11.00%
Aggregate common stock issued and sold prior to merger		$ 15,700,000
Shares issued price per share | $ / shares		$ 9.47
Private Acer | Convertible Promissory Notes
Organization Consolidation and Presentation of Financial Statement [Line Items]
Debt conversion, outstanding principal and accrued interest		$ 5,700,000
Merger of Private Acer with Opexa Merger Sub Incorporation
Organization Consolidation and Presentation of Financial Statement [Line Items]
Business combination date of completion	Sep. 19, 2017
Business combination date of agreement	Jun. 30, 2017
Reverse stock split ratio	0.09656678989

Significant Accounting Police27

Significant Accounting Polices - Schedule of Estimate Fair Value of Stock Options Granted (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Risk-free interest rate	1.93%	1.73%
Expected life (years)	6 years	5 years
Volatility	60.00%	60.00%
Dividend rate	0.00%	0.00%

Significant Accounting Police28

Significant Accounting Polices - Additional Information (Details)	12 Months Ended
	Dec. 31, 2017USD ($)Segment	Dec. 31, 2016USD ($)
Accounting Policies [Abstract]
Expected term of stock option granted to employees and directors, average contractual term and vesting period	10 years
Impaired of in-process research and development	$ 0
Uncertain tax positions, accruals	0	$ 0
Accruals for interest or penalties related to income tax matters	$ 0	$ 0
Number of operating segment | Segment	1

Purchase Accounting - Additiona

Purchase Accounting - Additional Information (Details) - USD ($)	Aug. 19, 2016	Dec. 31, 2017	Sep. 19, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Combination Separately Recognized Transactions [Line Items]
Goodwill		$ 7,647,267		$ 272,315
Impairment charges		0
Private Acer
Business Combination Separately Recognized Transactions [Line Items]
Equity interest held by registrant's shareholders			11.00%
Acquisition Date
Business Combination Separately Recognized Transactions [Line Items]
Goodwill		7,374,952
Fair value of consideration transferred in equity		7,007,069
Value of acquired legacy technology		0
Goodwill deductible for income tax purposes		0
Changes in goodwill after the initial purchase accounting		$ 0
Acquisition Date | Private Acer
Business Combination Separately Recognized Transactions [Line Items]
Equity interest held by registrant's shareholders		11.00%
Anchor
Business Combination Separately Recognized Transactions [Line Items]
Goodwill					$ 272,315
Gain loss on sale of stock	$ 0

Purchase Accounting - Fair Valu

Purchase Accounting - Fair Values of Assets Acquired and Liabilities Assumed (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Assets acquired and liabilities assumed:
Goodwill	$ 7,647,267	$ 272,315
Acquisition Date
Business Combination Separately Recognized Transactions [Line Items]
Consideration - issuance of securities and cash paid for fractional shares	7,007,069
Assets acquired and liabilities assumed:
Cash	1,058,276
Other assets	5,000
Accrued liabilities	(1,431,159)
Goodwill	7,374,952
Total purchase price	$ 7,007,069

Purchase Accounting - Unaudited

Purchase Accounting - Unaudited Pro Forma Operating Results (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Business Combinations [Abstract]
Net loss	$ (17,733,252)	$ (15,993,790)
Net loss per share - basic and diluted	$ (2.73)	$ (2.73)

Property and Equipment - Schedu

Property and Equipment - Schedule of Property and Equipment (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Property Plant And Equipment [Line Items]
Less accumulated depreciation	$ (4,042)	$ (4,645)
Property and equipment, net	62,984	6,217
Computer Hardware and Software
Property Plant And Equipment [Line Items]
Property and equipment, gross	16,555	$ 10,862
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	7,968
Furniture & Fixtures
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 42,503

Property and Equipment - Additi

Property and Equipment - Additional Information (Details)	12 Months Ended
	Dec. 31, 2017
Computer Hardware and Software
Property Plant And Equipment [Line Items]
Estimated useful lives	3 years
Tenant Improvements
Property Plant And Equipment [Line Items]
Estimated useful lives	1 year
Office Furniture
Property Plant And Equipment [Line Items]
Estimated useful lives	7 years

Accrued Expenses - Schedule of

Accrued Expenses - Schedule of Accrued Expenses (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Accounts Payable And Accrued Liabilities Current [Abstract]
Accrued legal	$ 174,592	$ 21,477
Accrued pre-commercial costs	341,159
Accrued consulting	102,156	13,105
Accrued audit and tax	111,250	39,820
Accrued license fees	817,578	205,444
Accrued contract manufacturing	218,108	126,700
Accrued contract research	99,140	16,800
Accrued miscellaneous expenses	73,348	14,682
Accrued expenses	$ 1,937,331	$ 438,028

Convertible Notes Payable - Add

Convertible Notes Payable - Additional Information (Details) - USD ($)	Mar. 22, 2017	Sep. 01, 2017	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	May 31, 2017
Debt Instrument [Line Items]
Non-cash interest expense					$ 242,982	$ 0
Private Acer | 2017 Notes
Debt Instrument [Line Items]
Aggregate principal amount	$ 3,125,000		$ 5,500,000		$ 5,500,000		$ 2,375,000
Notes accrued interest percentage	10.00%
Notes payable maturity date	Mar. 22, 2018
Conversion of shares discount rate in qualified financing		10.00%	20.00%	0.00%
Note conversion description					Conversion upon a Change in Control was at the discretion of the holder such that Private Acer would pay each holder the outstanding balance on their respective note or the note would be converted at a price per share equal to the lesser of $16.57
Debt instrument, convertible price per share			$ 16.57		$ 16.57
Debt issuance costs records as debt discount			$ 68,530		$ 68,530
Non-cash interest expense					242,982
Amortization of debt discount					68,530
Accrued interest					$ 174,452
Debt instrument converted into common stock					599,201
Debt Instrument Conversion Discount					$ 0

Commitments - Additional Inform

Commitments - Additional Information (Details) - Pending Litigation - Piper Jaffray & Co. - Private Acer	Sep. 27, 2017USD ($)
Loss Contingencies [Line Items]
Loss contingency payable fees	$ 1,097,207
Loss contingency closing date	Sep. 19, 2017
Financing aggregate consideration	$ 15,700,000
Reimbursement expenses	$ 67,496

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details) - USD ($)	Dec. 27, 2017	Dec. 14, 2017	Sep. 19, 2017	Dec. 31, 2017	Dec. 31, 2016	Sep. 18, 2017
Stockholders Equity [Line Items]
Conversion of convertible notes payable and accrued interest to common stock, value			$ 5,674,452	$ 5,674,452	$ 0
Conversion of convertible notes payable and accrued interest to common stock, shares			599,201
Issuance of common stock, net of issuance costs, shares			1,055,961
Shares issued price per share			$ 9.47
Proceeds from issuance of common stock			$ 10,000,000	21,506,842	$ 0
Unrecognized compensation expense				$ 2,500,000
Share based compensation arrangement by share based payment award, Average remaining vesting period				3 years 3 months 18 days
Weighted average grant date fair value of options granted				$ 8.25	$ 1.32
General and Administrative
Stockholders Equity [Line Items]
Stock based compensation expense				$ 111,000
Research and Development
Stockholders Equity [Line Items]
Stock based compensation expense				$ 307,000
2010 Stock Incentive Plan
Stockholders Equity [Line Items]
Number of common stock authorized for issuance			470,170			113,465
Options contractual term			10 years
Number of underlying shares cancelled			22,061
Available for the grant of future awards				159,572
2010 Stock Incentive Plan | Executive Officers and Employees
Stockholders Equity [Line Items]
Share-based compensation arrangement by share-based payment award, stock options vesting period			4 years
2010 Stock Incentive Plan | Executive Officers and Employees | One-year Anniversary of the Grant Date
Stockholders Equity [Line Items]
Share-based compensation arrangement by share-based payment award, Vesting percentage			25.00%
2010 Stock Incentive Plan | Executive Officers and Employees | Quarterly over Remaining Three Years
Stockholders Equity [Line Items]
Share-based compensation arrangement by share-based payment award, Vesting percentage			75.00%
2013 Stock Incentive Plan
Stockholders Equity [Line Items]
Number of common stock authorized for issuance			165,000
Options contractual term			10 years
Underwritten public offering and over-allotment option
Stockholders Equity [Line Items]
Issuance of common stock, net of issuance costs, shares	130,000	916,667
Shares issued price per share	$ 12	$ 12
Proceeds from issuance of common stock	$ 1,600,000	$ 11,000,000		$ 1,100,000
Registrant
Stockholders Equity [Line Items]
Common stock held by existing shareholders			736,950
Series A Convertible Redeemable Preferred Stock
Stockholders Equity [Line Items]
Number of preferred stock converted to common stock			638,416
Series B Convertible Redeemable Preferred Stock
Stockholders Equity [Line Items]
Number of preferred stock converted to common stock			970,238

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Option Activity under 2010 Plan and 2013 Plan (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Options
Number of Shares, Options outstanding at beginning of period	122,000
Number of Shares, Options granted	347,225
Number of Shares, Options exercised	0
Number of Shares, Options cancelled/forfeited	(5,625)
Number of Shares, Options outstanding at end of period	463,600	122,000
Number of Shares, Options exercisable at end of period	139,634
Weighted Average Exercise Price, Options
Weighted Average Exercise Price, Options outstanding at beginning of period	$ 2.55
Weighted Average Exercise Price, Options granted	14.10
Weighted Average Exercise Price, Options exercised	0
Weighted Average Exercise Price, Options cancelled/forfeited	2.55
Weighted Average Exercise Price, Options outstanding at end of period	11.23	$ 2.55
Weighted Average Exercise Price, Options exercisable at end of period	$ 3.49
Weighted Average Remaining Contract Term/Aggregate Intrinsic Value, Options
Weighted Average Remaining Contractual Term, Options outstanding at beginning of period	9 years 6 months	8 years 9 months 18 days
Weighted Average Remaining Contractual Term, Options exercisable at end of period	8 years 10 months 24 days
Aggregate Intrinsic Value, Options outstanding at end of period	$ 1,752,470
Aggregate Intrinsic Value, Options exercisable at end of period	$ 1,448,223

Stockholders' Equity - Summar39

Stockholders' Equity - Summary of Warrant Activity (Details) - Warrants	12 Months Ended
	Dec. 31, 2017USD ($)$ / sharesshares
Class Of Warrant Or Right [Line Items]
Number of Shares, Outstanding at beginning of period | shares	0
Number of Shares, Assumed in the merger at September 19, 2017 | shares	317,630
Number of Shares, Outstanding at end of period | shares	317,630
Number of Shares, Exercisable at end of period | shares	317,630
Weighted Average Exercise Price, Warrants
Weighted Average Exercise Price, Outstanding at beginning of period | $ / shares	$ 0
Weighted Average Exercise Price, Assumed in the merger at September 19, 2017 | $ / shares	123.61
Weighted Average Exercise Price, Outstanding at end of period | $ / shares	123.61
Weighted Average Exercise Price, Exercisable at end of period | $ / shares	$ 123.61
Weighted Average Remaining Contract Term, Warrants
Weighted Average Remaining Contract Term, Assumed in the merger at September 19, 2017	6 months 14 days
Weighted Average Remaining Contract Term, Outstanding at end of period	3 months 14 days
Weighted Average Remaining Contract Term, Exercisable at end of period	3 months 14 days
Intrinsic Value, Warrants
Intrinsic Value, Assumed in the merger at September 19, 2017 | $	$ 0
Intrinsic Value, Outstanding at end of period | $	0
Intrinsic Value, Exercisable at end of period | $	$ 0

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Line Items]
Provision for income taxes		$ 0	$ 0
Net operating loss carryforwards		$ 1,843,000	$ 537,000
Net operating loss carryforwards term		20 years
Net operating loss carryforwards expiration beginning year		2,024
Corporate federal income tax rate		34.00%	34.00%
Reduction in deferred tax assets		$ 8,200,000
Scenario Forecast
Income Tax Disclosure [Line Items]
Corporate federal income tax rate	21.00%
State
Income Tax Disclosure [Line Items]
Net operating loss carryforwards		$ 8,400,000

Income Taxes - Schedule of Comp

Income Taxes - Schedule of Components of Deferred Tax Assets and Liabilities (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Net operating loss carry forwards	$ 1,843,000	$ 537,000
Capitalized research and development costs	12,177,000	2,532,000
Accrued liabilities	25,000	15,000
Tax credit carryforwards	3,286,000	1,683,000
Stock-based compensation	116,000	38,000
Total deferred tax assets	17,447,000	4,805,000
Valuation allowance	(17,444,000)	$ (4,805,000)
Net deferred tax assets	3,000
Deferred tax liabilities	$ (3,000)

Income Taxes - Schedule of Reco

Income Taxes - Schedule of Reconciliation of Effective Income Tax Rate (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Federal statutory rate	34.00%	34.00%
R&D and Orphan drug credits	7.60%	15.80%
State income tax, net of federal tax benefit	(0.20%)	(17.70%)
Valuation allowance	18.20%	137.10%
Reduction in tax attributed related to deconsolidation of subsidiary	0.00%	(169.00%)
Tax reform impact	(57.80%)	0.00%
Other, net	(1.80%)	(0.20%)
Effective tax rate	0.00%	0.00%

Net Loss Per Share - Common Sto

Net Loss Per Share - Common Stock Underlying Potentially Dilutive Securities (Details) - shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Common stock dilutive securities	781,230	760,416
Convertible redeemable preferred stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Common stock dilutive securities		638,416
Warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Common stock dilutive securities	317,630
Options to purchase common stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Common stock dilutive securities	463,600	122,000