Acer Therapeutics (ACER) 10-Q 13 Nov 19 2019 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2019	Nov. 01, 2019
Cover [Abstract]
Entity Registrant Name	Acer Therapeutics Inc.
Entity Central Index Key	0001069308
Document Type	10-Q
Document Period End Date	Sep. 30, 2019
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Trading Symbol	ACER
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		10,095,176
Document Fiscal Period Focus	Q3
Document Fiscal Year Focus	2019
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity File Number	001-33004
Entity Tax Identification Number	32-0426967
Entity Address, Address Line One	One Gateway Center
Entity Address, Address Line Two	Suite 351
Entity Address, Address Line Three	300 Washington Street
Entity Address, City or Town	Newton
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02458
City Area Code	844
Local Phone Number	902-6100
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common Stock, $0.0001 par value per share
Security Exchange Name	NASDAQ
Entity Incorporation, State or Country Code	DE
Document Quarterly Report	true
Document Transition Report	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($)	Sep. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 16,121,903	$ 41,671,284
Prepaid expenses and other current assets	972,064	1,075,021
Total current assets	17,093,967	42,746,305
Property and equipment, net	158,796	130,867
Other assets:
Goodwill	7,647,267	7,647,267
In-process research and development	118,600	118,600
Other non-current assets	523,202	20,380
Total assets	25,541,832	50,663,419
Current liabilities:
Accounts payable	29,569	1,033,829
Accrued expenses	2,154,999	4,546,432
Other current liabilities	227,872
Total current liabilities	2,412,440	5,580,261
Other non-current liabilities	264,330
Total liabilities	2,676,770	5,580,261
Commitments and Contingencies (Note 6)
Stockholders’ equity:
Preferred stock, $0.0001 par value; authorized 10,000,000 shares; none issued and outstanding	0	0
Common stock, $0.0001 par value; authorized 150,000,000 shares; 10,095,176 and 10,087,363 shares issued and outstanding at September 30, 2019 and December 31, 2018, respectively	1,010	1,009
Additional paid-in capital	93,958,280	91,914,692
Accumulated deficit	(71,094,228)	(46,832,543)
Total stockholders’ equity	22,865,062	45,083,158
Total liabilities and stockholders’ equity	$ 25,541,832	$ 50,663,419

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2019	Dec. 31, 2018
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0.0001	$ 0.0001
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	$ 0.0001	$ 0.0001
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	10,095,176	10,087,363
Common stock, shares outstanding	10,095,176	10,087,363

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Operating expenses:
Research and development	$ 2,828,787	$ 2,377,916	$ 11,021,251	$ 7,140,046
General and administrative	2,533,678	1,729,446	13,683,852	5,874,423
Total operating expenses	5,362,465	4,107,362	24,705,103	13,014,469
Loss from operations	(5,362,465)	(4,107,362)	(24,705,103)	(13,014,469)
Other income, net:
Interest income	91,321	138,671	420,348	205,916
Foreign currency transaction gain	19,671	3,180	23,070	23,948
Total other income, net	110,992	141,851	443,418	229,864
Net loss	$ (5,251,473)	$ (3,965,511)	$ (24,261,685)	$ (12,784,605)
Net loss per share - basic and diluted	$ (0.52)	$ (0.43)	$ (2.40)	$ (1.59)
Weighted average common shares outstanding - basic and diluted	10,095,176	9,136,321	10,091,169	8,049,732

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Changes in Stockholders' Equity - USD ($)	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Beginning balance at Dec. 31, 2017	$ 22,335,537	$ 74,974	$ 47,812,215	$ (25,551,652)
Beginning balance, shares at Dec. 31, 2017		7,497,433
Costs associated with common stock issuance	(38,747)		(38,747)
Stock-based compensation	252,374		252,374
Net loss	(3,983,604)			(3,983,604)
Ending balance at Mar. 31, 2018	18,565,560	$ 74,974	48,025,842	(29,535,256)
Ending balance, shares at Mar. 31, 2018		7,497,433
Beginning balance at Dec. 31, 2017	22,335,537	$ 74,974	47,812,215	(25,551,652)
Beginning balance, shares at Dec. 31, 2017		7,497,433
Net loss	(12,784,605)
Ending balance at Sep. 30, 2018	53,105,730	$ 1,005	91,440,982	(38,336,257)
Ending balance, shares at Sep. 30, 2018		10,052,988
Beginning balance at Mar. 31, 2018	18,565,560	$ 74,974	48,025,842	(29,535,256)
Beginning balance, shares at Mar. 31, 2018		7,497,433
Reallocation for change in par value		$ (74,224)	74,224
Stock-based compensation	326,428		326,428
Net loss	(4,835,490)			(4,835,490)
Ending balance at Jun. 30, 2018	14,056,498	$ 750	48,426,494	(34,370,746)
Ending balance, shares at Jun. 30, 2018		7,497,433
Issuance of common stock, net of issuance costs	42,662,027	$ 255	42,661,772
Issuance of common stock, net of issuance costs, shares		2,555,555
Stock-based compensation	352,716		352,716
Net loss	(3,965,511)			(3,965,511)
Ending balance at Sep. 30, 2018	53,105,730	$ 1,005	91,440,982	(38,336,257)
Ending balance, shares at Sep. 30, 2018		10,052,988
Beginning balance at Dec. 31, 2018	$ 45,083,158	$ 1,009	91,914,692	(46,832,543)
Beginning balance, shares at Dec. 31, 2018	10,087,363	10,087,363
Stock-based compensation	$ 671,927		671,927
Net loss	(7,968,705)			(7,968,705)
Ending balance at Mar. 31, 2019	37,786,380	$ 1,009	92,586,619	(54,801,248)
Ending balance, shares at Mar. 31, 2019		10,087,363
Beginning balance at Dec. 31, 2018	$ 45,083,158	$ 1,009	91,914,692	(46,832,543)
Beginning balance, shares at Dec. 31, 2018	10,087,363	10,087,363
Issuance of stock in connection with stock option exercises, shares	7,813
Net loss	$ (24,261,685)
Ending balance at Sep. 30, 2019	$ 22,865,062	$ 1,010	93,958,280	(71,094,228)
Ending balance, shares at Sep. 30, 2019	10,095,176	10,095,176
Beginning balance at Mar. 31, 2019	$ 37,786,380	$ 1,009	92,586,619	(54,801,248)
Beginning balance, shares at Mar. 31, 2019		10,087,363
Stock-based compensation	715,366		715,366
Issuance of stock in connection with stock option exercises	92,272	$ 1	92,271
Issuance of stock in connection with stock option exercises, shares		7,813
Net loss	(11,041,507)			(11,041,507)
Ending balance at Jun. 30, 2019	27,552,511	$ 1,010	93,394,256	(65,842,755)
Ending balance, shares at Jun. 30, 2019		10,095,176
Stock-based compensation	564,024		564,024
Net loss	(5,251,473)			(5,251,473)
Ending balance at Sep. 30, 2019	$ 22,865,062	$ 1,010	$ 93,958,280	$ (71,094,228)
Ending balance, shares at Sep. 30, 2019	10,095,176	10,095,176

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($)	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash flows from operating activities:
Net loss	$ (24,261,685)	$ (12,784,605)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	1,951,317	931,517
Depreciation	40,573	16,624
Loss on disposal of property and equipment	57,578
Changes in operating assets and liabilities
Prepaid expenses and other current assets	102,957	(262,207)
Accounts payable	(1,004,260)	499,566
Accrued expenses	(2,391,433)	(377,813)
Other non-current assets	(10,620)	(20,380)
Net cash used in operating activities	(25,515,573)	(11,997,298)
Cash flows from investing activities:
Purchase of property and equipment	(126,080)	(84,928)
Net cash used in investing activities	(126,080)	(84,928)
Cash flows from financing activities:
Proceeds from the issuance of common stock, net of issuance costs		42,623,281
Proceeds from the exercise of stock options	92,272
Net cash provided by financing activities	92,272	42,623,281
Net (decrease) increase in cash and cash equivalents	(25,549,381)	30,541,055
Cash and cash equivalents, beginning of period	41,671,284	15,644,355
Cash and cash equivalents, end of period	$ 16,121,903	$ 46,185,410

Nature of Operations and Basis

Nature of Operations and Basis of Presentation	9 Months Ended
	Sep. 30, 2019
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 Delaware 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 serious rare and life-threatening diseases with significant unmet medical needs. The Company’s pipeline includes three clinical-stage candidates: EDSIVO™ (celiprolol) for the treatment of vascular Ehlers-Danlos syndrome (“vEDS”) in patients with a confirmed type III collagen (COL3A1) mutation; ACER-001 (a fully taste-masked, immediate release formulation of sodium phenylbutyrate) for the treatment of various inborn errors of metabolism, including urea cycle disorders (“UCD”) and Maple Syrup Urine Disease (“MSUD”); and osanetant for the treatment of induced vasomotor symptoms (“iVMS”) where hormone replacement therapy (“HRT”) is likely contraindicated. The Company’s product candidates are believed to present a comparatively de-risked profile, having one or more of a favorable safety profile, clinical proof-of-concept data, mechanistic differentiation, and/or accelerated paths for development through specific programs and procedures established by the United States Food and Drug Administration (“FDA”). 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. The Company believes that its existing cash and cash equivalents of approximately $16.1 million at September 30, 2019, will be sufficient to allow the Company to fund its current operating plan through the end of 2020 and, as a result, through at least twelve months from the filing of the Company’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2019. There can be no assurance, however, that the current operating plan will be achieved in the time frame anticipated by the Company, or that its cash resources will fund the Company’s operating plan for the period anticipated by the Company. Until the Company can generate a sufficient amount of product revenue to finance its cash requirements, which would require the Company to obtain regulatory approval for and successfully commercialize one or more of its product candidates, the Company expects to finance its future cash needs primarily through the issuance of additional equity and potentially through borrowing and strategic alliances. On June 24, 2019, the Company received a Complete Response Letter from the FDA regarding its new drug application (“NDA”) for EDSIVO TM TM 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”). 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 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. Delaware Reincorporation and Subsidiary Merger On May 15, 2018, the Company changed its state of incorporation from the State of Texas to the State of Delaware pursuant to a plan of conversion, dated May 15, 2018. As a result of this reincorporation, the par value of the Company’s preferred stock was changed to $0.0001 from no par value and the par value of the Company’s common stock was reduced to $0.0001 from $0.01. Immediately following the Reincorporation, the holding company structure was eliminated by merging wholly-owned subsidiary Private Acer with and into the Company (the “Subsidiary Merger”). The Company was the surviving corporation in connection with the Subsidiary Merger. Basis of Presentation Accounting principles generally accepted in the United States (“GAAP”) 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. Private Acer was incorporated on December 26, 2013, as part of a reorganization whereby Acer Therapeutics, LLC was converted into a corporation organized under the laws of the State of Delaware. All intercompany balances and transactions have been eliminated in consolidation. 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”). The accompanying unaudited condensed consolidated financial statements are unaudited and have been prepared in accordance with GAAP for interim financial information and with the instructions to Form 10-Q and Regulation S-X. The unaudited condensed consolidated financial statements have been prepared on the same basis as the audited annual consolidated financial statements and reflect, in the opinion of management, all adjustments of a normal and recurring nature that are necessary for the fair presentation of the Company’s financial position, results of operations, stockholders’ equity and cash flows for the periods presented. The results of operations for the three and nine months ended September 30, 2019 are not necessarily indicative of the results to be expected for the year ending December 31, 2019 or for any other future annual or interim period. The condensed consolidated balance sheet as of December 31, 2018, included herein, was derived from the audited consolidated financial statements as of that date but does not include all disclosures required by GAAP. These unaudited condensed consolidated financial state

Significant Accounting Polices

Significant Accounting Polices	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Significant Accounting Polices	2. SIGNIFICANT ACCOUNTING POLICIES The Company’s significant accounting policies are described in Note 2, “Significant Accounting Policies,” in its Annual Report on Form 10-K for the year ended December 31, 2018. Leases In the first quarter of 2019, the Company adopted ASU No. 2016-02, Leases (Topic 842) incremental borrowing rate and amortizing over the remaining terms of the leases. Stock-Based Compensation The Company records stock-based payments at fair value. The measurement date for compensation expense related to awards is generally the date of the grant. The fair value of awards 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 during the nine-month period ending September 30, 2019 and 2018 using the Black-Scholes option pricing model: 2019 2018 Risk-free interest rate 1.68% - 2.57% 2.35% – 2.98% Expected life (years) 6.25 6.25 Volatility 60% 60% Dividend rate 0% 0% 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 condensed financial statements and reported amounts of revenues and expenses during the reporting period. Estimates having relatively higher significance include stock-based compensation, contract manufacturing accruals, and income taxes. Actual results could differ from those estimates and changes in estimates may occur. Income Taxes The Company recorded no income tax expense or benefit during the three and nine months ended September 30, 2019 and 2018, due to a full valuation allowance recognized against its net deferred tax assets. 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 stock-based awards, were not included in the calculation of the diluted loss per share because to do so would be anti-dilutive. Recently Adopted Accounting Pronouncements In February 2016, the FASB issued ASU No. 2016-02, which establishes new accounting and disclosure requirements for leases. ASU No. 2016-02 requires lessees to classify most leases as either finance or operating leases and to initially recognize a lease liability and right-of-use asset. The Company adopted ASU 2016-02 in the first quarter of 2019 using the effective date approach to recognize and measure leases as of the adoption date. The Company has elected to utilize the available practical expedient to not separate lease components from non-lease components as well as the package of practical expedients that allows the Company not to reassess (1) whether any expired or existing contracts as of the adoption date are or contain a lease, (2) lease classification for any expired or existing leases as of the adoption date and (3) initial direct costs for any existing leases as of the adoption date. As a result of the adoption of this guidance, the Company recorded a non-cash transaction to recognize on January 1, 2019 lease liabilities totaling $0.4 million and right-of-use-assets totaling $0.4 million, which will be amortized over the remaining terms of the leases. In June 2018, the FASB issued ASU No. 2018-07, Compensation—Stock Compensation (Topic 718) Improvements to Nonemployee Share-Based Payment Accounting

Property and Equipment

Property and Equipment	9 Months Ended
	Sep. 30, 2019
Property Plant And Equipment [Abstract]
Property and Equipment	3. PROPERTY AND EQUIPMENT Property and equipment consisted of the following at September 30, 2019 and December 31, 2018: September 30, 2019 December 31, 2018 Computer hardware and software $ 60,750 $ 58,868 Leasehold improvements 7,648 7,648 Furniture and fixtures 145,487 96,013 Subtotal property and equipment, gross 213,885 162,529 Less accumulated depreciation (55,089 ) (31,662 ) Property and equipment, net $ 158,796 $ 130,867

Accrued Expenses

Accrued Expenses	9 Months Ended
	Sep. 30, 2019
Accounts Payable And Accrued Liabilities Current [Abstract]
Accrued Expenses	4. ACCRUED EXPENSES Accrued expenses consisted of the following at September 30, 2019 and December 31, 2018: September 30, 2019 December 31, 2018 Accrued contract manufacturing $ 926,000 $ 1,079,314 Accrued pre-commercial costs 502,125 85,000 Accrued consulting 189,214 49,940 Accrued legal 185,652 111,543 Accrued accounting, audit, and tax fees 172,000 102,000 Accrued miscellaneous expenses 150,125 119,861 Accrued payroll and payroll taxes 29,883 1,302,728 Accrued license fees — 1,567,368 Accrued contract research and regulatory consulting — 128,678 Total accrued expenses $ 2,154,999 $ 4,546,432

Leases

Leases	9 Months Ended
	Sep. 30, 2019
Leases [Abstract]
Leases	5. LEASES On March 6, 2018, the Company entered into a lease agreement (the “Newton Lease”) commencing on October 1, 2018 for certain premises which consist of 2,760 square feet of office space located in Newton, Massachusetts (the “Newton Premises”) to serve as its corporate headquarters. On March 5, 2019, the Company entered into a lease agreement to amend the Newton Lease and to lease an additional 1,600 square feet of office space, commencing on June 1, 2019, located in Newton, Massachusetts (the “Additional Newton Premises”) to serve as additional space for its corporate headquarters. The term of the lease for the Newton Premises and the Additional Newton Premises expires on May 31, 2022. In addition, the Company is required to share in certain taxes and operating expenses of the Newton Premises and the Additional Newton Premises. The Company entered into a Triple Net Lease (the “Bend Lease”) effective April 1, 2018 for certain premises consisting of 2,288 square feet of office space located in Bend, Oregon (the “Bend Premises”) to serve as a satellite facility. The term of the Bend Lease commenced on April 1, 2018 and expires on March 31, 2021 (the “Bend Term”). The Company has an option to extend the Bend Term for up to two additional periods of three years and a right of first refusal to lease an additional suite in the same building. The leases for the Newton Premises, the Additional Newton Premises, and the Bend Premises are classified as operating leases. In the first quarter of 2019, the Company adopted ASU 2016-02 and recorded a non-cash transaction to recognize a right-of-use asset of $0.4 million in other non-current assets, as well as a lease liability of $0.2 million in other current liabilities and $0.2 million in other non-current liabilities. In the second quarter of 2019, the Company recognized an additional right-of-use asset of $0.2 million as well as an additional lease liability of $0.1 million in other current liabilities and $0.1 million in other non-current liabilities in conjunction with the commencement of the lease for the Additional Newton Premises. The Company’s lease liability represents the net present value of future lease payments utilizing a discount rate of 8%, which corresponds to the Company’s incremental borrowing rate. As of September 30, 2019, the weighted average remaining lease term was 2.5 years. For the three and nine months ended September 30, 2019, the Company recorded expense of $56 thousand and $142 thousand, respectively, related to the leases. For the three and nine months ended September 30, 2018, the Company recorded lease expense of $36 thousand and $96 thousand, respectively. During the three and nine months ended September 30, 2019, the Company made cash payments of $67 thousand and $145 thousand, respectively, for amounts included in the measurement of lease liabilities. The Company is therefore reporting a right-of-use asset of $0.5 million in Other non-current assets and lease liabilities totaling $0.5 million in Other current liabilities and Other non-current liabilities as of September 30, 2019. The following table reconciles the undiscounted lease liabilities to the total lease liabilities recognized on the unaudited condensed consolidated balance sheet as of September 30, 2019: Undiscounted lease liabilities for years ending December 31,: 2019 (remaining) $ 56,652 2020 229,323 2021 186,784 2022 72,400 Total undiscounted lease liabilities $ 545,159 Less effects of discounting (52,957 ) Total lease liabilities as of September 30, 2019 $ 492,202 Reported as of September 30, 2019: Other current liabilities $ 227,872 Other non-current liabilities 264,330 Total lease liabilities $ 492,202 Future minimum lease payments at December 31, 2018 were as follows: Years Ending December 31: Minimum Lease Payments 2019 $ 151,579 2020 155,813 2021 93,204 Total $ 400,596

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2019
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	6 . COMMITMENTS AND CONTINGENCIES License Agreements In April 2014, Private Acer obtained exclusive rights to intellectual property relating to ACER-001 and preclinical and clinical data, through a 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, make payments upon achievement of defined milestones, and pay royalties in the low single-digit percent range on net sales of any developed product over the royalty term. In August 2016, Private Acer signed an agreement with Assistance Publique—Hôpitaux de Paris, Hôpital Européen Georges Pompidou (“AP-HP”) (via its Department of Clinical Research and Development) granting the Company the exclusive worldwide rights to access and use data from a randomized, controlled clinical study of celiprolol. The Company used this pivotal clinical data to support a new drug application regulatory filing for EDSIVO TM In September 2018, the Company entered into a License Agreement for Development and Exploitation with AP-HP to acquire the exclusive worldwide intellectual property rights to three European patent applications relating to certain uses of celiprolol including (i) the optimal dose of celiprolol in treating vEDS patients, (ii) the use of celiprolol during pregnancy and (iii) the use of celiprolol to treat kyphoscoliotic Ehlers-Danlos syndrome (type VI). Pursuant to the agreement, the Company will reimburse AP-HP for certain costs and will pay annual maintenance fee payments. Subject to a minimum royalty amount, the Company will also pay royalty payments on annual net sales of celiprolol during the royalty term in the low single digit percent range, depending upon whether there is a valid claim of a licensed patent. Under the agreement, the Company will control and pay the costs of ongoing patent prosecution and maintenance for the licensed applications. The Company may terminate the agreement in its sole discretion upon written notice to AP-HP, and AP-HP may terminate the agreement in the event the Company fails to make the required payments after notice and opportunity to cure. Additionally, the agreement will terminate if the Company terminates clinical development, marketing approval is withdrawn by the health or regulatory authorities in all countries, the Company ceases to do business or there is a procedure of winding-up by court decision against the Company. The Company subsequently filed three United States patent applications on this subject matter in October 2018. In December 2018, the Company entered into an exclusive license agreement with Sanofi granting the Company worldwide rights to osanetant, a clinical-stage, selective, non-peptide tachykinin NK3 receptor antagonist. The agreement required the Company to make a certain upfront payment to Sanofi, make payments upon achievement of defined development and sales milestones and pay royalties on net sales of osanetant over the royalty term. The Company plans to initially pursue development of osanetant as a potential treatment for iVMS where HRT is likely contraindicated. Litigation From time to time, the Company may become involved in litigation or proceedings relating to claims arising out of its operations. In addition, on September 27, 2017, Piper Jaffray & Co. (“Piper”) 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 pursuant to an August 30, 2016 engagement letter between the parties and an April 28, 2017 addendum thereto by failing to pay Piper (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 and (ii) $67,496 in reimbursement for expenses incurred by Piper pursuant to the engagement letter. On November 10, 2017, Private Acer filed an answer and counterclaim in the lawsuit, denying Piper’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 filed a reply to the counterclaims denying the essential allegations, and discovery has commenced. On February 22, 2019, Piper filed a motion for summary judgment. In response, Private Acer filed its opposition to Piper's motion on March 22, 2019. Piper subsequently filed its reply to Private Acer's opposition on April 5, 2019. Piper's motion is currently pending before the Court and oral argument on the summary judgment motion was held on September 4, 2019. No ruling on the motion has yet been issued by the Court. The Company has not recorded a liability as of September 30, 2019 because a potential loss is not probable or reasonably estimable given the preliminary nature of the proceedings. In addition, on July 1, 2019, plaintiff Tyler Sell filed a putative class action lawsuit, Sell v. Acer Therapeutics Inc., against the Company, Chris Schelling and Harry Palmin, in the United States District Court for the Southern District of New York. The complaint alleges that prior to the receipt of the Complete Response Letter from the FDA, Acer made material false and misleading statements or omissions which allegedly constitute securities fraud. On August 12, 2019, a shareholder’s derivative action, Gress v. Acer Therapeutics Inc., was filed in the United States District Court for the District of Delaware against the Company and certain of its officers and directors, asserting damages resulting from alleged breach of fiduciary duties, based on the same facts at issue in the Sell case. The Company believes both suits are without merit and intends to defend itself vigorously. No activity has occurred in either suit thus far. The Company has not recorded a liability as of September 30, 2019 because a potential loss is not probable or reasonably estimable given the preliminary nature of the proceedings.

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2019
Equity [Abstract]
Stockholders' Equity	7 . STOCKHOLDERS’ EQUITY Underwritten Public Offering On August 3, 2018, the Company completed an underwritten public offering of 2,555,555 shares of common stock, including 333,333 shares sold pursuant to the underwriters’ full exercise of their option to purchase additional shares to cover over-allotments, at a public offering price of $18.00 per share. The Company received aggregate net proceeds of approximately $42.7 million, after deducting underwriting discounts, commissions and offering-related expenses of approximately $3.3 million. At-the-Market Facility On November 9, 2018, the Company entered into a sales agreement (the “Agreement”) with Roth Capital Partners, LLC. The Agreement provides a facility for the offer and sale of shares of common stock from time to time having an aggregate offering price of up to $50,000,000 depending upon market demand, in transactions deemed to be an “at-the-market” offering. The Company has no obligation to sell any shares of common stock pursuant to the Agreement and may at any time suspend sales pursuant to the Agreement. Either party may terminate the Agreement at any time without liability . 2018 Stock Incentive Plan The Company’s 2018 Stock Incentive Plan (the “2018 Plan”), adopted on May 14, 2018, provides for the grant of up to 500,000 shares of common stock as stock options, restricted stock, stock appreciation rights, restricted stock units, performance-based awards and cash-based awards that may be settled in cash, stock or other property to employees, executive officers, directors, and consultants. In addition to the 500,000 shares, the total number of shares reserved for issuance under the 2018 Plan also consists of the sum of the number of shares subject to outstanding awards under the Company’s 2010 Stock Incentive Plan, as amended and restated (the “2010 Plan”), and the 2013 Stock Incentive Plan, as amended (the “2013 Plan”), as of the effective date of the 2018 Plan that are subsequently forfeited or terminated for any reason prior to being exercised or settled, plus the number of shares subject to vesting restrictions under the 2010 Plan and the 2013 Plan on the effective date of the 2018 Plan that are subsequently forfeited, plus the number of shares reserved but not issued or subject to outstanding grants under the 2010 Plan and the 2013 Plan as of the effective date of the 2018 Plan, up to a maximum of 635,170 shares in aggregate. In addition, the number of shares authorized for issuance under the 2018 Plan is automatically increased (the “evergreen provision”) on the first day of each fiscal year beginning on January 1, 2019, and ending on (and including) January 1, 2028, in an amount equal to the lesser of (i) 4% of the outstanding shares of common stock on the last day of the immediately preceding fiscal year, or (ii) another amount (including zero) determined by the Company’s Board of Directors. Any shares subject to awards granted under the 2018 Plan that are forfeited or terminated before being exercised or settled, or are not delivered to the participant because such award is settled in cash, will again become available for issuance under the 2018 Plan. Shares withheld to satisfy the grant, exercise price or tax withholding obligation related to an award will again become available for issuance under the 2018 Plan. The 2018 Plan is administered by the Company’s Board of Directors, which may in turn delegate authority to administer the plan to a committee such as the Compensation Committee, referred to herein as the 2018 Plan administrator. Subject to the terms of the 2018 Plan, the 2018 Plan administrator will determine recipients, the number of shares or amount of cash subject to awards to be granted, whether an option is to be an incentive stock options or non-incentive stock options and the terms and conditions of the stock awards, including the period of their exercisability and vesting. Subject to the limitations set forth below, the 2018 Plan administrator will also determine the exercise price of options granted under the 2018 Plan. The 2018 Plan expressly provides that, without the approval of the stockholders, the 2018 Plan administrator does not have the authority to reduce the exercise price of any outstanding stock options or stock appreciation rights under the 2018 Plan (except in connection with certain corporate transactions, such as stock splits, certain dividends, recapitalizations, reorganizations, mergers, spin-offs and the like), or cancel any outstanding underwater stock options or stock appreciation rights in exchange for cash or new stock awards under the 2018 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 generally vest either 1) 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, or 2) for certain stock options granted on September 18, 2019, 50% vest on each of January 1, 2021 and January 1, 2022, assuming continued service, and with vesting acceleration in full immediately prior to a change in control. Restricted stock units generally vest and are settled upon the first anniversary of the grant date. At September 30, 2019, after the authorization on January 1, 2019 of 403,495 additional shares according to the evergreen provision, 89,815 shares of common stock remained available for the grant of future awards under the 2018 Plan. 2013 Stock Incentive Plan Private Acer’s 2013 Plan, which was assumed by the Company in connection with the Merger, provided 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 were generally granted with an exercise price equal to the fair value of the common stock at the date of grant and had contractual terms of 10 years. At September 30, 2019, all shares available under the 2013 Plan were subject to outstanding equity awards, and no new awards may be granted under the 2013 Plan. 2010 Stock Incentive Plan The Company’s 2010 Plan, as amended and restated, provided 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. Option awards were generally granted with an exercise price equal to the fair value of the common stock at the date of grant and had contractual terms of 10 years. At September 30, 2019, all shares available under the 2010 Plan were subject to outstanding equity awards, and no new awards may be granted under the 2010 Plan. A summary of option activity under the 2018 Plan, 2013 Plan, and 2010 Plan for the nine months ended September 30, 2019, is as follows: Year-to-Date Activity Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (Years) Aggregate Intrinsic Value (in millions) Options outstanding at December 31, 2018 781,725 $ 16.34 9.0 Granted 1,063,150 13.84 Exercised (7,813 ) 11.81 Cancelled/forfeited (451,398 ) 22.95 Options outstanding at September 30, 2019 1,385,664 12.12 8.9 $ 0.1 Options exercisable at September 30, 2019 328,707 $ 11.34 7.2 $ 0.1 A summary of restricted stock unit activity under the 2018 Plan for the nine months ended September 30, 2019, is as follows: Year-to-Date Activity Number of Shares Weighted Average Grant Date Fair Value Per Share Aggregate Intrinsic Value (in millions) Non-vested outstanding at December 31, 2018 — — Granted 15,000 $ 23.60 Cancelled/forfeited (6,000 ) Non-vested outstanding at September 30, 2019 9,000 $ 23.60 $ 0.0 At September 30, 2019, there was approximately $6.7 million of unrecognized compensation expense related to the stock-based compensation arrangements granted under all plans. The average remaining vesting period for options was 2.5 years. The weighted average grant date fair value of options granted during the nine months ended September 30, 2019 was $8.03. The amount of stock-based compensation expense recorded to research and development expenses and to general and administrative expenses is detailed in table below: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Stock-based compensation Research and development $ 166,289 $ 179,930 $ 785,423 $ 515,584 General and administrative 397,735 172,786 1,165,894 415,933 $ 564,024 $ 352,716 $ 1,951,317 $ 931,517 Warrants On January 23, 2018, all outstanding and unexercised Series J warrants to purchase an aggregate of 2,942 shares of common stock expired. On January 29, 2018, all outstanding and unexercised Series K warrants to purchase an aggregate of 2,262 shares of common stock expired. On April 9, 2018, all outstanding and unexercised Series M warrants to purchase an aggregate of 301,452 shares of common stock expired. At September 30, 2019 and December 31, 2018, there were no warrants outstanding.

Net Loss Per Share

Net Loss Per Share	9 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Net Loss Per Share	8 . 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 September 30, 2019 and 2018, the number of shares of common stock underlying potentially dilutive securities are comprised of: September 30, 2019 2018 Warrants — 10,974 Options to purchase common stock and unvested, unsettled restricted stock units 1,394,664 751,100 Total 1,394,664 762,074

Restructuring

Restructuring	9 Months Ended
	Sep. 30, 2019
Restructuring And Related Activities [Abstract]
Restructuring	9. RESTRUCTURING On June 24, 2019, the Company received a Complete Response Letter from the FDA regarding its New Drug Application for EDSIVO TM TM

Significant Accounting Polices

Significant Accounting Polices (Policies)	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Leases	Leases In the first quarter of 2019, the Company adopted ASU No. 2016-02, Leases (Topic 842) incremental borrowing rate and amortizing over the remaining terms of the leases.
Stock-Based Compensation	Stock-Based Compensation The Company records stock-based payments at fair value. The measurement date for compensation expense related to awards is generally the date of the grant. The fair value of awards 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 during the nine-month period ending September 30, 2019 and 2018 using the Black-Scholes option pricing model: 2019 2018 Risk-free interest rate 1.68% - 2.57% 2.35% – 2.98% Expected life (years) 6.25 6.25 Volatility 60% 60% Dividend rate 0% 0%
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 condensed financial statements and reported amounts of revenues and expenses during the reporting period. Estimates having relatively higher significance include stock-based compensation, contract manufacturing accruals, and income taxes. Actual results could differ from those estimates and changes in estimates may occur.
Income Taxes	Income Taxes The Company recorded no income tax expense or benefit during the three and nine months ended September 30, 2019 and 2018, due to a full valuation allowance recognized against its net deferred tax assets.
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 stock-based awards, were not included in the calculation of the diluted loss per share because to do so would be anti-dilutive.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements In February 2016, the FASB issued ASU No. 2016-02, which establishes new accounting and disclosure requirements for leases. ASU No. 2016-02 requires lessees to classify most leases as either finance or operating leases and to initially recognize a lease liability and right-of-use asset. The Company adopted ASU 2016-02 in the first quarter of 2019 using the effective date approach to recognize and measure leases as of the adoption date. The Company has elected to utilize the available practical expedient to not separate lease components from non-lease components as well as the package of practical expedients that allows the Company not to reassess (1) whether any expired or existing contracts as of the adoption date are or contain a lease, (2) lease classification for any expired or existing leases as of the adoption date and (3) initial direct costs for any existing leases as of the adoption date. As a result of the adoption of this guidance, the Company recorded a non-cash transaction to recognize on January 1, 2019 lease liabilities totaling $0.4 million and right-of-use-assets totaling $0.4 million, which will be amortized over the remaining terms of the leases. In June 2018, the FASB issued ASU No. 2018-07, Compensation—Stock Compensation (Topic 718) Improvements to Nonemployee Share-Based Payment Accounting

Significant Accounting Police_2

Significant Accounting Polices (Tables)	9 Months Ended
	Sep. 30, 2019
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 during the nine-month period ending September 30, 2019 and 2018 using the Black-Scholes option pricing model: 2019 2018 Risk-free interest rate 1.68% - 2.57% 2.35% – 2.98% Expected life (years) 6.25 6.25 Volatility 60% 60% Dividend rate 0% 0%

Property and Equipment (Tables)

Property and Equipment (Tables)	9 Months Ended
	Sep. 30, 2019
Property Plant And Equipment [Abstract]
Schedule of Property and Equipment	Property and equipment consisted of the following at September 30, 2019 and December 31, 2018: September 30, 2019 December 31, 2018 Computer hardware and software $ 60,750 $ 58,868 Leasehold improvements 7,648 7,648 Furniture and fixtures 145,487 96,013 Subtotal property and equipment, gross 213,885 162,529 Less accumulated depreciation (55,089 ) (31,662 ) Property and equipment, net $ 158,796 $ 130,867

Accrued Expenses (Tables)

Accrued Expenses (Tables)	9 Months Ended
	Sep. 30, 2019
Accounts Payable And Accrued Liabilities Current [Abstract]
Schedule of Accrued Expenses	Accrued expenses consisted of the following at September 30, 2019 and December 31, 2018: September 30, 2019 December 31, 2018 Accrued contract manufacturing $ 926,000 $ 1,079,314 Accrued pre-commercial costs 502,125 85,000 Accrued consulting 189,214 49,940 Accrued legal 185,652 111,543 Accrued accounting, audit, and tax fees 172,000 102,000 Accrued miscellaneous expenses 150,125 119,861 Accrued payroll and payroll taxes 29,883 1,302,728 Accrued license fees — 1,567,368 Accrued contract research and regulatory consulting — 128,678 Total accrued expenses $ 2,154,999 $ 4,546,432

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2019
Leases [Abstract]
Reconciliation of Undiscounted Lease Liabilities to Total Lease Liabilities	The following table reconciles the undiscounted lease liabilities to the total lease liabilities recognized on the unaudited condensed consolidated balance sheet as of September 30, 2019: Undiscounted lease liabilities for years ending December 31,: 2019 (remaining) $ 56,652 2020 229,323 2021 186,784 2022 72,400 Total undiscounted lease liabilities $ 545,159 Less effects of discounting (52,957 ) Total lease liabilities as of September 30, 2019 $ 492,202 Reported as of September 30, 2019: Other current liabilities $ 227,872 Other non-current liabilities 264,330 Total lease liabilities $ 492,202
Schedule of Future Minimum Lease Payments	Future minimum lease payments at December 31, 2018 were as follows: Years Ending December 31: Minimum Lease Payments 2019 $ 151,579 2020 155,813 2021 93,204 Total $ 400,596

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2019
Equity [Abstract]
Summary of Option Activity under 2018 Plan, 2013 Plan and 2010 Plan	A summary of option activity under the 2018 Plan, 2013 Plan, and 2010 Plan for the nine months ended September 30, 2019, is as follows: Year-to-Date Activity Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (Years) Aggregate Intrinsic Value (in millions) Options outstanding at December 31, 2018 781,725 $ 16.34 9.0 Granted 1,063,150 13.84 Exercised (7,813 ) 11.81 Cancelled/forfeited (451,398 ) 22.95 Options outstanding at September 30, 2019 1,385,664 12.12 8.9 $ 0.1 Options exercisable at September 30, 2019 328,707 $ 11.34 7.2 $ 0.1
Summary of Restricted Stock Unit Activity under 2018 Plan	A summary of restricted stock unit activity under the 2018 Plan for the nine months ended September 30, 2019, is as follows: Year-to-Date Activity Number of Shares Weighted Average Grant Date Fair Value Per Share Aggregate Intrinsic Value (in millions) Non-vested outstanding at December 31, 2018 — — Granted 15,000 $ 23.60 Cancelled/forfeited (6,000 ) Non-vested outstanding at September 30, 2019 9,000 $ 23.60 $ 0.0
Summary of Stock-Based Compensation Expense	The amount of stock-based compensation expense recorded to research and development expenses and to general and administrative expenses is detailed in table below: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Stock-based compensation Research and development $ 166,289 $ 179,930 $ 785,423 $ 515,584 General and administrative 397,735 172,786 1,165,894 415,933 $ 564,024 $ 352,716 $ 1,951,317 $ 931,517

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	9 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Schedule of Number of Shares of Common Stock Underlying Potentially Dilutive Securities	As of September 30, 2019 and 2018, the number of shares of common stock underlying potentially dilutive securities are comprised of: September 30, 2019 2018 Warrants — 10,974 Options to purchase common stock and unvested, unsettled restricted stock units 1,394,664 751,100 Total 1,394,664 762,074

Nature of Operations and Basi_2

Nature of Operations and Basis of Presentation - Additional Information (Details)	Jun. 28, 2019Employee	Sep. 19, 2017	Sep. 30, 2019USD ($)$ / shares	Dec. 31, 2018USD ($)$ / shares	May 15, 2018$ / shares	May 14, 2018$ / shares
Organization Consolidation and Presentation of Financial Statement [Line Items]
Cash and cash equivalents | $			$ 16,121,903	$ 41,671,284
Corporate restructuring, reduction of full-time workforce percentage	60.00%
Corporate restructuring, reduction of full-time workforce employees | Employee	48
Preferred stock, no par value						$ 0
Preferred stock, par value			$ 0.0001	$ 0.0001
Common stock, par value			$ 0.0001	$ 0.0001		$ 0.01
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
Delaware Reincorporation and Subsidiary Merger
Organization Consolidation and Presentation of Financial Statement [Line Items]
Merger incorporation description			On May 15, 2018, the Company changed its state of incorporation from the State of Texas to the State of Delaware pursuant to a plan of conversion, dated May 15, 2018. As a result of this reincorporation, the par value of the Company’s preferred stock was changed to $0.0001 from no par value and the par value of the Company’s common stock was reduced to $0.0001 from $0.01. Immediately following the Reincorporation, the holding company structure was eliminated by merging wholly-owned subsidiary Private Acer with and into the Company (the “Subsidiary Merger”). The Company was the surviving corporation in connection with the Subsidiary Merger.
Date of reincorporation			May 15, 2018
Preferred stock, par value					$ 0.0001
Common stock, par value					$ 0.0001

Significant Accounting Police_3

Significant Accounting Polices - Schedule of Estimate Fair Value of Stock Options Granted (Details)	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Accounting Policies [Abstract]
Risk-free interest rate, minimum	1.68%	2.35%
Risk-free interest rate, maximum	2.57%	2.98%
Expected life (years)	6 years 3 months	6 years 3 months
Volatility	60.00%	60.00%
Dividend rate	0.00%	0.00%

Significant Accounting Police_4

Significant Accounting Polices - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Jun. 30, 2019	Mar. 31, 2019	Jan. 01, 2019
Accounting Policies [Abstract]
Income tax expense (benefit)	$ 0	$ 0	$ 0	$ 0
Operating lease liability	492,202		492,202				$ 400,000
Operating lease right of use asset	$ 500,000		$ 500,000		$ 200,000	$ 400,000	$ 400,000

Property and Equipment - Schedu

Property and Equipment - Schedule of Property and Equipment (Details) - USD ($)	Sep. 30, 2019	Dec. 31, 2018
Property Plant And Equipment [Line Items]
Subtotal property and equipment, gross	$ 213,885	$ 162,529
Less accumulated depreciation	(55,089)	(31,662)
Property and equipment, net	158,796	130,867
Computer Hardware and Software
Property Plant And Equipment [Line Items]
Subtotal property and equipment, gross	60,750	58,868
Leasehold Improvements
Property Plant And Equipment [Line Items]
Subtotal property and equipment, gross	7,648	7,648
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Subtotal property and equipment, gross	$ 145,487	$ 96,013

Accrued Expenses - Schedule of

Accrued Expenses - Schedule of Accrued Expenses (Details) - USD ($)	Sep. 30, 2019	Dec. 31, 2018
Accounts Payable And Accrued Liabilities Current [Abstract]
Accrued contract manufacturing	$ 926,000	$ 1,079,314
Accrued pre-commercial costs	502,125	85,000
Accrued consulting	189,214	49,940
Accrued legal	185,652	111,543
Accrued accounting, audit, and tax fees	172,000	102,000
Accrued miscellaneous expenses	150,125	119,861
Accrued payroll and payroll taxes	29,883	1,302,728
Accrued license fees		1,567,368
Accrued contract research and regulatory consulting		128,678
Total accrued expenses	$ 2,154,999	$ 4,546,432

Leases - Additional Information

Leases - Additional Information (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)Term	Sep. 30, 2018USD ($)	Jun. 30, 2019USD ($)	Mar. 31, 2019USD ($)	Mar. 05, 2019ft²	Jan. 01, 2019USD ($)	Apr. 01, 2018ft²	Mar. 06, 2018ft²
Lessee Lease Description [Line Items]
Operating lease right of use asset	$ 500,000		$ 500,000		$ 200,000	$ 400,000		$ 400,000
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:OtherAssetsNoncurrent		us-gaap:OtherAssetsNoncurrent
Operating lease liability, current	$ 227,872		$ 227,872
Operating lease liability, non-current	$ 264,330		$ 264,330
Operating lease discount rate	8.00%		8.00%
Operating lease, weighted average remaining lease term	2 years 6 months		2 years 6 months
Operating lease, cash payment made	$ 67,000		$ 145,000
Operating lease expense	56,000	$ 36,000	142,000	$ 96,000
Operating lease liability	$ 492,202		$ 492,202					$ 400,000
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilities		us-gaap:OtherLiabilities
ASU 2016-02
Lessee Lease Description [Line Items]
Operating lease liability, current					100,000	200,000
Operating lease liability, non-current					$ 100,000	$ 200,000
Newton Lease | Newton, Massachusetts
Lessee Lease Description [Line Items]
Lease agreement date			Mar. 6, 2018
Lease commencement date			Oct. 1, 2018
Square feet of office space leased | ft²										2,760
Amended Newton Lease | Newton, Massachusetts
Lessee Lease Description [Line Items]
Lease agreement date			Mar. 5, 2019
Lease commencement date			Jun. 1, 2019
Square feet of office space leased | ft²							1,600
Lease expiration date			May 31, 2022
Bend Lease | Oregon
Lessee Lease Description [Line Items]
Lease agreement date			Apr. 1, 2018
Lease commencement date			Apr. 1, 2018
Square feet of office space leased | ft²									2,288
Lease expiration date			Mar. 31, 2021
Maximum additional periods of option to extend the bend term | Term			2
Option to extend bend term for duration period			3 years

Leases - Reconciliation of Undi

Leases - Reconciliation of Undiscounted Lease Liabilities to Total Lease Liabilities (Detail) - USD ($)	Sep. 30, 2019	Jan. 01, 2019
Undiscounted lease liabilities for years ending December 31,:
2019 (remaining)	$ 56,652
2020	229,323
2021	186,784
2022	72,400
Total undiscounted lease liabilities	545,159
Less effects of discounting	(52,957)
Total lease liabilities as of September 30, 2019	492,202	$ 400,000
Operating lease liability, current	227,872
Operating lease liability, non-current	264,330
Total lease liabilities	$ 492,202	$ 400,000

Leases - Schedule of Future Min

Leases - Schedule of Future Minimum Lease Payments (Details)	Dec. 31, 2018USD ($)
Leases [Abstract]
2019	$ 151,579
2020	155,813
2021	93,204
Total	$ 400,596

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details)	Sep. 27, 2017USD ($)	Sep. 30, 2018Patent	Sep. 30, 2019
Private Acer | Pending Litigation | Piper Jaffray & Co.
Commitments And 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
Assistance Publique – Hôpitaux de Paris (“AP-HP”) | License Agreement
Commitments And Contingencies [Line Items]
Agreement entered date		2018-09
Number of patent applications | Patent		3
Assistance Publique – Hôpitaux de Paris (“AP-HP”) | Private Acer | License Agreement
Commitments And Contingencies [Line Items]
Agreement entered date			2016-08

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details) - USD ($)	Sep. 18, 2019	Nov. 09, 2018	Aug. 03, 2018	May 14, 2018	Apr. 09, 2018	Jan. 29, 2018	Jan. 23, 2018	Sep. 19, 2017	Sep. 30, 2019	Dec. 31, 2018
Stockholders Equity [Line Items]
Stock issued during period, shares, new issues			2,555,555
Public offering price per share			$ 18
Proceeds from issuance initial public offering, after deduction underwriting discounts, commissions			$ 42,700,000
Payments for Underwriting Expense			$ 3,300,000
Number of share outstanding									1,385,664	781,725
Awards granted under the plan									1,063,150
Unrecognized compensation expense									$ 6,700,000
Share based compensation arrangement by share based payment award, Average remaining vesting period									2 years 6 months
Weighted average grant date fair value of options granted									$ 8.03
Warrants outstanding									0	0
Series J Warrants
Stockholders Equity [Line Items]
Warrants expired for aggregate share of common stock to purchase							2,942
Series K Warrants
Stockholders Equity [Line Items]
Warrants expired for aggregate share of common stock to purchase						2,262
Series M Warrants
Stockholders Equity [Line Items]
Warrants expired for aggregate share of common stock to purchase					301,452
2018 Stock Incentive Plan
Stockholders Equity [Line Items]
Number of common stock authorized for issuance				500,000					403,495
Share-based compensation arrangement by share-based payment award, description									In addition, the number of shares authorized for issuance under the 2018 Plan is automatically increased (the “evergreen provision”) on the first day of each fiscal year beginning on January 1, 2019, and ending on (and including) January 1, 2028, in an amount equal to the lesser of (i) 4% of the outstanding shares of common stock on the last day of the immediately preceding fiscal year, or (ii) another amount (including zero) determined by the Company’s Board of Directors. Any shares subject to awards granted under the 2018 Plan that are forfeited or terminated before being exercised or settled, or are not delivered to the participant because such award is settled in cash, will again become available for issuance under the 2018 Plan. Shares withheld to satisfy the grant, exercise price or tax withholding obligation related to an award will again become available for issuance under the 2018 Plan.
Share-based compensation arrangement by share-based payment award, expiration date									Jan. 1, 2028
Share-based compensation arrangement by share-based payment award, percentage of outstanding our common stock									4.00%
Options contractual term				10 years
Available for the grant of future awards									89,815
2018 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
2018 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 Share-based compensation arrangement by share-based payment award, Vesting percentage				25.00%
2018 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 Share-based compensation arrangement by share-based payment award, Vesting percentage				75.00%
2018 Stock Incentive Plan | Executive Officers and Employees | January 1, 2021
Stockholders Equity [Line Items]
Share-based compensation arrangement by share-based payment award, Vesting percentage Share-based compensation arrangement by share-based payment award, Vesting percentage	50.00%
2018 Stock Incentive Plan | Executive Officers and Employees | January 1, 2022
Stockholders Equity [Line Items]
Share-based compensation arrangement by share-based payment award, Vesting percentage Share-based compensation arrangement by share-based payment award, Vesting percentage	50.00%
2013 Stock Incentive Plan
Stockholders Equity [Line Items]
Number of common stock authorized for issuance								165,000
Options contractual term								10 years
Awards granted under the plan									0
2010 Stock Incentive Plan
Stockholders Equity [Line Items]
Number of common stock authorized for issuance								470,170
Options contractual term								10 years
Awards granted under the plan									0
Maximum | 2010 and 2013 Stock Incentive Plan
Stockholders Equity [Line Items]
Number of share outstanding				635,170
Over-Allotment Option
Stockholders Equity [Line Items]
Stock issued during period, shares, new issues			333,333
At-the-Market Facility | Maximum
Stockholders Equity [Line Items]
Aggregate offering price of common stock		$ 50,000,000

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Option Activity under 2013 Plan and 2010 Plan (Details) - USD ($) $ / shares in Units, $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Options
Number of Shares, Options outstanding at beginning of period	781,725
Number of Shares, Options Granted	1,063,150
Number of Shares, Options Exercised	(7,813)
Number of Shares, Options Cancelled/forfeited	(451,398)
Number of Shares, Options outstanding at end of period	1,385,664	781,725
Number of Shares, Options exercisable at end of period	328,707
Weighted Average Exercise Price, Options
Weighted Average Exercise Price, Options outstanding at beginning of period	$ 16.34
Weighted Average Exercise Price, Options Granted	13.84
Weighted Average Exercise Price, Options Exercised	11.81
Weighted Average Exercise Price, Options Cancelled/forfeited	22.95
Weighted Average Exercise Price, Options outstanding at end of period	12.12	$ 16.34
Weighted Average Exercise Price, Options exercisable at end of period	$ 11.34
Weighted Average Remaining Contract Term, Options
Weighted Average Remaining Contractual Term, Options outstanding at beginning of period	8 years 10 months 24 days	9 years
Weighted Average Remaining Contractual Term, Options exercisable at end of period	7 years 2 months 12 days
Aggregate Intrinsic Value, Options outstanding at end of period	$ 0.1
Aggregate Intrinsic Value, Options exercisable at end of period	$ 0.1

Stockholders' Equity - Summar_2

Stockholders' Equity - Summary of Restricted Stock Unit Activity under 2018 Plan (Details) - Restricted Stock Units $ / shares in Units, $ in Millions	9 Months Ended
	Sep. 30, 2019USD ($)$ / sharesshares
Restricted Stock Units
Number of Shares, Granted	15,000
Number of Shares, Cancelled/forfeited	(6,000)
Number of Shares, Non-Vested outstanding at end of period	9,000
Weighted Average Grant Date Fair Value Per Share
Weighted Average Grant Date Fair Value Per Share, Granted | $ / shares	$ 23.60
Weighted Average Grant Date Fair Value Per Share, Non-Vested outstanding at end of the period | $ / shares	$ 23.60
Aggregate Intrinsic Value
Aggregate Intrinsic Value, Non-Vested outstanding at end of the period | $	$ 0

Stockholders' Equity - Summar_3

Stockholders' Equity - Summary of Stock-Based Compensation Expense (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Stockholders Equity [Line Items]
Stock-based compensation	$ 564,024	$ 352,716	$ 1,951,317	$ 931,517
Research and Development
Stockholders Equity [Line Items]
Stock-based compensation	166,289	179,930	785,423	515,584
General and Administrative
Stockholders Equity [Line Items]
Stock-based compensation	$ 397,735	$ 172,786	$ 1,165,894	$ 415,933

Net Loss Per Share - Schedule o

Net Loss Per Share - Schedule of Number of Shares of Common Stock Underlying Potentially Dilutive Securities (Details) - shares	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Common stock dilutive securities	1,394,664	762,074
Warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Common stock dilutive securities		10,974
Options to purchase common stock and unvested, unsettled restricted stock units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Common stock dilutive securities	1,394,664	751,100

Restructuring - Additional Info

Restructuring - Additional Information (Details) $ in Millions	Jun. 28, 2019Employee	Jun. 30, 2019USD ($)
Restructuring Cost And Reserve [Line Items]
One-time severance-related charge		$ 1.5
Corporate restructuring, reduction of full-time workforce percentage	60.00%
Corporate restructuring, reduction of full-time workforce employees | Employee	48
General and Administrative
Restructuring Cost And Reserve [Line Items]
One-time severance-related charge		1
Research and Development
Restructuring Cost And Reserve [Line Items]
One-time severance-related charge		$ 0.5