Acer Therapeutics (ACER) 10-Q 7 Nov 13 2013 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 30, 2013	Nov. 05, 2013
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	30-Sep-13	'
Document Fiscal Year Focus	'2013	'
Document Fiscal Period Focus	'Q3	'
Trading Symbol	'OPXA	'
Entity Registrant Name	'OPEXA THERAPEUTICS, INC.	'
Entity Central Index Key	'0001069308	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Smaller Reporting Company	'
Entity Common Stock, Shares Outstanding	'	22,729,487

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Sep. 30, 2013	Dec. 31, 2012
Current assets:	'	'
Cash and cash equivalents	$20,172,485	$592,004
Other current assets	1,304,146	1,077,546
Total current assets	21,476,631	1,669,550
Property & equipment, net of accumulated depreciation of $1,752,655 and $1,494,510, respectively	1,226,511	1,265,041
Restricted cash	'	1,000,000
Deferred financing costs, net of amortization of $0 and $58,639, respectively	'	211,479
Other long-term assets	85,047	'
Total assets	22,788,189	4,146,070
Current liabilities:	'	'
Accounts payable	914,317	412,096
Accrued expenses	1,056,300	473,879
Deferred revenue	1,395,348	'
Total current liabilities	3,365,965	885,975
Long term liabilities:	'	'
Deferred revenue	2,686,878	'
Total liabilities	6,052,843	1,262,738
Commitments and contingencies	'	'
Stockholders' equity:	'	'
Preferred stock, no par value, 10,000,000 shares authorized, none issued and outstanding	'	'
Common stock, $0.01 par value, 100,000,000 shares authorized, 22,729,487 and 6,249,369 shares issued and outstanding	227,295	62,494
Additional paid in capital	139,017,515	112,432,458
Deficit accumulated during the development stage	-122,509,464	-109,611,620
Total stockholders' equity	16,735,346	2,883,332
Total liabilities and stockholders' equity	22,788,189	4,146,070
Unrelated Party Transactions	'	'
Long term liabilities:	'	'
Convertible debt, net of unamortized discount	'	318,658
Related Party Transactions	'	'
Long term liabilities:	'	'
Convertible debt, net of unamortized discount	'	$58,105

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Property & equipment, accumulated depreciation	$1,752,655	$1,494,510
Deferred financing costs, amortization	0	58,639
Preferred stock, no par value	'	'
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	'	'
Preferred stock, shares outstanding	'	'
Common stock, par value	$0.01	$0.01
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	22,729,487	6,249,369
Common stock, shares outstanding	22,729,487	6,249,369
Unrelated Party Transactions	'	'
Convertible debt, unamortized discount	0	3,136,342
Related Party Transactions	'	'
Convertible debt, unamortized discount	$0	$571,895

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (USD $)	3 Months Ended		9 Months Ended		128 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013
Revenue:	'	'	'	'	'
Option Revenue	$348,837	'	$917,774	'	$917,774
Research and development	2,494,463	1,455,938	6,338,859	4,504,243	82,836,210
General and administrative	626,668	532,474	2,479,708	1,878,236	32,597,324
Depreciation and amortization	90,935	81,514	258,144	225,365	1,908,302
Loss on disposal of assets	'	'	'	'	513,345
Operating loss	-2,863,229	-2,069,926	-8,158,937	-6,607,844	-116,937,407
Interest income	4,448	61	9,388	256	1,368,085
Other income, net	'	'	37,910	'	699,056
Loss on extinguishment of debt	-2,518,912	'	-2,518,912	'	-906,472
Gain/Loss on derivative instruments	'	-136,889	'	-136,889	1,941,826
Gain on sale of technology	'	'	'	'	3,000,000
Interest expense	-346,239	-151,029	-2,267,293	-152,002	-11,674,552
Net loss	($5,723,932)	($2,357,783)	($12,897,844)	($6,896,479)	($122,509,464)
Basic and diluted loss per share	($0.39)	($0.40)	($1.29)	($1.20)	'
Weighted average shares outstanding	14,721,474	5,762,028	10,011,453	5,762,028	'

Consolidated_Statements_of_Cha

Consolidated Statements of Changes In Stockholders' Equity (USD $)

Total

Beneficial Conversion Feature

Warrants Attached to Debt

Purchase Agreements

Accrued Interest

Common Stock

Common Stock

Common Stock

Additional Paid in Capital

Additional Paid in Capital

Additional Paid in Capital

Additional Paid in Capital

Additional Paid in Capital

Accumulated Deficit

Purchase Agreements

Accrued Interest

Beneficial Conversion Feature

Warrants Attached to Debt

Purchase Agreements

Accrued Interest

Beginning balance at Dec. 31, 2012

$2,883,332

'

'

'

'

$62,494

'

'

$112,432,458

'

'

'

'

($109,611,620)

Beginning balance (in shares) at Dec. 31, 2012

'

'

'

'

'

6,249,369

'

'

'

'

'

'

'

'

Conversion of convertible notes (in shares)

'

'

'

'

'

2,079,960

'

'

'

'

'

'

'

'

Conversion of convertible notes

4,275,053

'

'

'

'

20,799

'

'

4,254,254

'

'

'

'

'

Discount

'

141,829

195,969

'

'

'

'

'

'

141,829

195,969

'

'

'

Shares issued for cash, net of offering costs (in shares)

'

'

'

'

'

14,275,952

'

'

'

'

'

'

'

'

Shares issued for cash, net of offering costs

21,022,269

'

'

'

'

142,760

'

'

20,879,509

'

'

'

'

'

Shares issued (in shares)

900,000

'

'

'

'

'

975

123,231

'

'

'

'

'

'

Shares issued

'

'

'

1,234

188,543

'

10

1,232

'

'

'

1,224

187,311

'

Warrant expense

219,553

'

'

'

'

'

'

'

219,553

'

'

'

'

'

Option expense

705,408

'

'

'

'

'

'

'

705,408

'

'

'

'

'

Net loss

-12,897,844

'

'

'

'

'

'

'

'

'

'

'

'

-12,897,844

Ending balance at Sep. 30, 2013

$16,735,346

'

'

'

'

$227,295

'

'

$139,017,515

'

'

'

'

($122,509,464)

Ending balance (in shares) at Sep. 30, 2013

'

'

'

'

'

22,729,487

'

'

'

'

'

'

'

'

Consolidated_Statements_of_Cha1

Consolidated Statements of Changes In Stockholders' Equity (Parenthetical) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013
Share purchase agreement, value	$1.50

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	9 Months Ended		128 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013
Cash flows from operating activities	'	'	'
Net loss	($12,897,844)	($6,896,479)	($122,509,464)
Adjustments to reconcile net loss to net cash used in operating activities	'	'	'
Stock payable for acquired research and development	'	'	112,440
Stock issued for acquired research and development	'	'	26,286,589
Stock issued for services	'	'	2,061,743
Stock issued for debt in excess of principal	'	'	109,070
Amortization of discount on notes payable due to warrants and beneficial conversion feature	1,613,354	34,600	8,470,084
Loss on extinguishment of debt	2,518,912	'	906,472
Depreciation	258,144	225,365	1,908,302
Amortization of debt financing costs	125,248	24,710	708,265
Option and warrant expense	924,961	542,766	17,190,894
(Gain) loss on derivative instruments	'	136,889	-1,941,826
Loss on disposition of fixed assets	'	'	513,345
Changes in:	'	'	'
Other current assets	20,481	-1,025,807	-1,132,572
Accounts payable - third parties and related parties	216,938	-130,278	56,287
Accrued expenses	745,999	-219,372	1,351,237
Deferred revenue	4,082,226	'	4,082,226
Other assets	-85,047	'	-85,047
Net cash used in operating activities	-2,476,628	-7,307,606	-61,911,955
Cash flows from investing activities	'	'	'
Purchase of property & equipment	-214,197	-512,048	-2,436,396
Restricted cash	1,000,000	-1,000,000	'
Net cash provided by (used in) investing activities	785,803	-1,512,048	-2,436,396
Cash flows from financing activities	'	'	'
Common stock and warrants sold for cash, net of offering costs	21,319,153	'	70,772,950
Common stock repurchased and canceled	'	'	-325
Proceeds from exercise of warrants and options	'	'	1,248,588
Deferred financing and offering costs	-147,847	-136,943	-657,339
Repayments on notes payable	-450,000	'	-761,222
Net cash provided by financing activities	21,271,306	3,948,057	84,520,836
Net change in cash and cash equivalents	19,580,481	-4,871,597	20,172,485
Cash and cash equivalents at beginning of period	592,004	7,109,215	'
Cash and cash equivalents at end of period	20,172,485	2,237,618	20,172,485
Cash paid for:	'	'	'
Income tax	'	'	'
Interest	19,638	1,460	174,747
NON-CASH TRANSACTIONS	'	'	'
Issuance of common stock to Sportan shareholders	'	'	147,733
Issuance of common stock for accrued interest	188,543	'	977,830
Issuance of warrants to placement agent	'	'	37,453
Conversion of notes payable and accrued interest to common stock	4,275,053	'	11,985,033
Conversion of accrued liabilities to common stock	'	'	197,176
Conversion of accounts payable to note payable	'	'	93,364
Discount on convertible notes relating to:	'	'	'
Warrants	195,969	2,314,635	6,170,341
Beneficial conversion feature	141,829	1,497,634	3,444,982
Stock attached to notes	'	'	1,287,440
Fair value of derivative instrument	'	'	4,680,220
Derivative reclassified to equity	'	'	2,349,266
Unpaid additions to property and equipment	5,417	11,730	5,417
Amortization of deferred offering costs to paid-in capital	'	'	47,339
Shares issued as deferred offering costs	1,234	'	150,365
Unpaid offering costs	296,884	170,831	296,884
Third Parties	'	'	'
Cash flows from financing activities	'	'	'
Proceeds from convertible debt	550,000	3,455,000	13,288,184
Related Parties	'	'	'
Cash flows from financing activities	'	'	'
Proceeds from convertible debt	100,000	630,000	730,000
Repayments on notes payable	($100,000)	'	($100,000)

Basis_of_Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2013
Basis of Presentation	'
	Note 1.  Basis of Presentation
	The accompanying interim unaudited consolidated financial statements of Opexa Therapeutics, Inc. (“Opexa” or the “Company”), a development stage company, have been prepared in accordance with accounting principles generally accepted in the United States of America and the rules of the Securities and Exchange Commission (“SEC”) and should be read in conjunction with the audited financial statements and notes thereto contained in Opexa’s latest Annual Report filed with the SEC on Form 10-K.  In the opinion of management, all adjustments, consisting of normal recurring adjustments, necessary for a fair presentation of financial position and the results of operations for the interim periods presented have been reflected herein. The results of operations for interim periods are not necessarily indicative of the results to be expected for the full year.  Notes to the financial statements that would substantially duplicate the disclosure contained in the audited financial statements for the most recent fiscal year as reported in Form 10-K have been omitted.
	The accompanying consolidated financial statements include the accounts of Opexa and its wholly owned subsidiary, Opexa Hong Kong Limited (“Opexa Hong Kong”). All intercompany balances and transactions have been eliminated in the consolidation.

Significant_Accounting_Polices

Significant Accounting Polices	9 Months Ended
	Sep. 30, 2013
Significant Accounting Polices	'
	Note 2.  Significant Accounting Polices
	Revenue Recognition.  Opexa recognizes revenue in accordance with FASB ASC 605, Revenue Recognition. ASC 605 requires that four basic criteria must be met before revenue can be recognized: (1) persuasive evidence of an arrangement exists; (2) delivery has occurred or services rendered; (3) consideration is fixed or determinable; and (4) collectability is reasonably assured.
	On February 4, 2013, Opexa entered into an Option and License Agreement (the “Merck Agreement”) with Ares Trading SA (“Merck”), a wholly owned subsidiary of Merck Serono S.A.  Pursuant to the terms, Merck has an option to acquire an exclusive, worldwide (excluding Japan) license of the Company’s Tcelna® program for the treatment of multiple sclerosis (“MS”).  Tcelna is currently in a Phase IIb clinical trial in patients with Secondary Progressive MS (“SPMS”). The option may be exercised by Merck prior to or upon the Company’s completion of the Phase IIb Trial.
	Opexa received an upfront payment of $5 million for granting the option. If the option is exercised, Merck would pay the Company an upfront license fee of $25 million unless Merck is unable to advance directly into a Phase III clinical trial of Tcelna for SPMS without a further Phase II clinical trial (as determined by Merck), in which event the upfront license fee would be $15 million. After exercising the option, Merck would be solely responsible for funding development, regulatory and commercialization activities for Tcelna in MS, although the Company would retain an option to co-fund certain development in exchange for increased royalty rates.  The Company would also retain rights to Tcelna in Japan, certain rights with respect to the manufacture of Tcelna, and rights outside of MS.
	Opexa evaluated the Merck Agreement and determined that the $5 million upfront payment from Merck has stand-alone value. Opexa’s continuing performance obligations, in connection with the $5 million payment, include the execution and completion of the Phase IIb clinical trial in SPMS using commercially reasonable efforts at the Company’s own costs.  As a stand-alone value term in the Merck Agreement, the $5 million upfront payment is determined to be a single unit of accounting, and is recognized as revenue on a straight-line basis over the exclusive option period based on the expected completion term of the Phase IIb clinical trial in SPMS. Opexa includes the unrecognized portion of the $5 million as deferred revenue on the consolidated balance sheets.
	Cash and Cash Equivalents.  Opexa considers all highly liquid investments with an original maturity of three months or less, when purchased, to be cash equivalents. Investments with maturities in excess of three months but less than one year are classified as short-term investments and are stated at fair market value.
	Opexa primarily maintains cash balances on deposit in accounts at a U.S.-based financial institution.  The aggregate cash balance on deposit in these accounts is insured by the Federal Deposit Insurance Corporation up to $250,000.  Opexa’s cash balances on deposit in these accounts may, at times, exceed the federally insured limits.  Opexa has not experienced any losses in such accounts.
	At September 30, 2013, Opexa invested approximately $19.1 million in a savings account.  For the nine months ended September 30, 2013, the savings account recognized an average market yield of 0.19%.  Interest income of $9,388 was recognized for the nine months ended September 30, 2013 in the consolidated statements of operations.

Other_Current_Assets

Other Current Assets	9 Months Ended
	Sep. 30, 2013
Other Current Assets	'
	Note 3.  Other Current Assets
	Other current assets consisted of the following at September 30, 2013 and December 31, 2012:
	Description	September 30,		December 31,
		2013		2012
	Supplies inventory	$	803,371	$	604,179
	Deferred offering costs		326,630		341,166
	Prepaid expenses		174,145		132,201
		$	1,304,146	$	1,077,546
	Supplies inventory at September 30, 2013 and December 31, 2012 includes reagents and supplies that will be used to manufacture Tcelna and placebo product in Opexa’s Phase IIb clinical study. Opexa expects to amortize these prepaid reagents and supplies to research and development costs in the consolidated statements of operations over the course of the clinical study.
	Deferred offering costs at September 30, 2013 and December 31, 2012 include costs incurred from third parties in connection with the implementation of an at-the-market program (“ATM Agreement”) in September 2012 pursuant to which Opexa may sell shares of its common stock from time to time depending upon market demand through a sales agent in transactions deemed to be an “at-the-market” offering as defined in Rule 415 of the Securities Act of 1933.  As of September 30, 2013, the remaining costs of $88,446 in connection with the implementation of the ATM Agreement remained capitalized and are included in other current assets in the consolidated balance sheets. Upon the sales of shares of common stock under the ATM Agreement, the remaining capitalized costs are offset against the proceeds of such sales of shares of common stock.
	Deferred offering costs at September 30, 2013 also include costs incurred from third parties in connection with the implementation of a $1.5 million purchase agreement and a $15 million purchase agreement (collectively, the “purchase agreements”) in November 2012 pursuant to which Opexa has the right to sell to Lincoln Park Capital Fund, LLC (“Lincoln Park”) an aggregate of up to $16.5 million in shares of its common stock, subject to certain conditions and limitations.  As of September 30, 2013, the remaining costs of $238,184 in connection with the implementation of the purchase agreements remained capitalized and are included in other current assets in the consolidated balance sheets.  Upon the sales of shares of common stock under the purchase agreements, the remaining capitalized costs are offset against the proceeds of such sales of shares of common stock.
	Prepaid expenses at September 30, 2013 include the current portion of legal costs of $44,070 incurred from third parties in conjunction with the Merck Agreement (see Note 6).

Restricted_Cash

Restricted Cash	9 Months Ended
	Sep. 30, 2013
Restricted Cash	'
	Note 4.  Restricted Cash
	Pursuant to the July 2012 Note financing, $1.0 million of the gross proceeds were initially required to be maintained in a segregated account and subject to a deposit control agreement while the July 2012 Notes were outstanding.  Pursuant to a waiver executed by the holders of in excess of two-thirds (66-2/3%) of the principal amount of the outstanding July 2012 Notes and accepted by Opexa, the amount of the cash subject to the deposit control agreement was reduced to $500,000 on January 29, 2013.  In exchange for such waiver, the Company issued warrants to the holders of the July 2012 Notes to purchase an aggregate of 187,500 shares of the Company’s common stock (see Note 10).
	Opexa entered into an Omnibus Amendment to All Outstanding 12% Convertible Secured Promissory Notes of Opexa Therapeutics, Inc. and Associated Registration Rights Agreement (the “July 2012 Note Amendment”) on September 23, 2013 with certain holders of its July 2012 Notes with respect to certain terms relating to conversion of the July 2012 Notes (see Note 7).  Pursuant to the July 2012 Note Amendment and the Company’s subsequent conversion of all outstanding July 2012 Notes into shares of common stock on September 24, 2013 (see Note 7), the deposit control agreement was effectively terminated and the remaining $500,000 balance in the controlled account is reported as cash and cash equivalents on the consolidated balance sheets.

Deferred_Financing_Costs

Deferred Financing Costs	9 Months Ended
	Sep. 30, 2013
Deferred Financing Costs	'
	Note 5.  Deferred Financing Costs
	Deferred financing costs consisted of costs incurred from third parties in conjunction with the July 2012 Notes.  The costs in connection with the debt financing were capitalized and are amortized to interest expense over the term of the related debt. In connection with the September 24, 2013 conversion of the July 2012 Notes, the balance of the unamortized deferred financing costs of $86,231 was charged to loss on debt extinguishment. During the nine months ended September 30, 2013, Opexa amortized $125,248 of deferred financing costs as interest expense.

Other_Assets

Other Assets	9 Months Ended
	Sep. 30, 2013
Other Assets	'
	Note 6.  Other Assets
	Other long-term assets at September 30, 2013 consist of legal costs incurred from third parties in conjunction with the Merck Agreement.  These costs were capitalized and are amortized to general and administrative expenses on the consolidated statements of operations in conjunction with the recognition of revenue on a straight-line basis over the exclusive option period based on the term of the Phase IIb clinical trial in SPMS. During the nine months ended September 30, 2013, Opexa amortized $28,799 of legal costs to general and administrative expenses on the consolidated statements of operations.  Opexa included the current portion of the legal costs of $44,070 in other current assets on the consolidated balance sheets and the long term portion of the legal costs of $85,047 in other long-term assets on the consolidated balance sheets as of September 30, 2013.

Convertible_Promissory_Notes

Convertible Promissory Notes	9 Months Ended
	Sep. 30, 2013
Convertible Promissory Notes	'
	Note 7.  Convertible Promissory Notes
	On January 23, 2013, Opexa closed a private offering consisting of convertible notes (the “January 2013 Notes”) and warrants to purchase shares of common stock for gross proceeds of $650,000 of which $100,000 was from a related party (see Note 8).  The January 2013 Notes were scheduled to mature on January 23, 2014 and accrued interest at the rate of 12% per annum, compounded annually.  The January 2013 Notes were convertible into common stock at the option of the investors at a price of $1.30 per share, subject to certain limitations.  The principal balance plus accrued interest was payable within five business days of the receipt by Opexa of an aggregate of at least $7.5 million in proceeds from the sale of its equity securities and/or as payments from one or more partners or potential partners in return for granting a license, other rights, or an option to license or otherwise acquire rights with respect to Tcelna.
	The January 2013 Notes were analyzed at issuance for a beneficial conversion feature and Opexa concluded that a beneficial conversion feature existed. The beneficial conversion feature was measured using the commitment-date stock price and was determined to be $141,829 of which $21,820 was attributable to the related party.  Opexa also analyzed the Notes for derivative accounting consideration and determined that derivative accounting does not apply.
	In connection with the issuance of the January 2013 Notes, Opexa also issued Series J warrants to purchase an aggregate of 243,750 shares of Opexa’s common stock (see Note 10), subject to certain limitations and adjustments.  The relative fair value of the warrant liability of $195,969, together with the beneficial conversion feature of $141,829, were recognized as a debt discount and were amortized to interest expense in the consolidated statements of expenses over the term of the January 2013 Notes using the effective interest method.
	On February 26, 2013, following the receipt of $3.25 million in gross proceeds during February 2013 from the sale of common stock and warrants to purchase shares of common stock, and following the receipt of the upfront payment of $5 million from Merck on February 20, 2013, Opexa paid principal and interest totaling $567,368 to holders of the January 2013 Notes, of which $100,000 was to a related party, and issued 77,034 shares of common stock to one holder of the January 2013 Notes who elected to convert the principal of $100,000.
	During the nine months ended September 30, 2013, the debt discount of $337,798 in connection with the January 2013 Notes was fully amortized to interest expense.
	In February 2013, three of the third party holders of the July 2012 Notes elected to convert their principal amounts of $900,000 into shares of the Company’s Series A convertible preferred stock with further immediate conversion into 288,229 shares of the Company’s common stock.
	On September 23, 2013, the Company entered into the July 2012 Note Amendment with certain holders of its July 2012 Notes with respect to certain terms relating to conversion of the July 2012 Notes.  Pursuant to the July 2012 Note Amendment, all outstanding Notes were amended such that, in addition to the existing conversion arrangements, the Notes became convertible at the Company’s election directly into shares of common stock (rather than any intermediate conversion to shares of Series A convertible preferred stock), at a conversion price of not less than $1.50 nor more than $2.25, based on the most recent closing market price of the Company’s common stock on the NASDAQ Stock Market at the time of the Company’s election to convert the Notes plus any accrued but unpaid interest through the conversion date  into shares of common stock.  Notes in the aggregate principal amount of $3,185,000 were outstanding at the time of the July 2012 Note Amendment.
	On September 24, 2013, the Company converted the principal amount of the July 2012 Notes and unpaid interest totaling $3,275,053 into an aggregate of 1,714,697 shares of common stock at a conversion price of $1.91, which was the most recent closing market price of the Company’s common stock on the NASDAQ Stock Market when the Company effected such conversion. The Company determined that the conversion of the July 2012 Notes qualifies as a debt extinguishment since the Notes were converted based on the amended conversion price.  Consequently, the Company recorded a loss on extinguishment of debt of $2,518,912, which represents the difference in the fair value of the shares issued of $3,275,053 and the carrying amount of the Notes (including accrued interest of $98,053) of $756,141 at the date of conversion. The carrying amount of the Notes is net of the unamortized discount and deferred financing costs at the date of conversion amounting to $2,432,681 and $86,231, respectively.
	The following table provides a summary of the changes in convertible debt – third parties, net of unamortized discount, during the nine months ended September 30, 2013:
	Balance at December 31, 2012	$	318,658
	January 2013 Notes, face value		550,000
	Discount on beneficial conversion feature of January 2013 Notes at issuance		(120,009	)
	Discount on fair value of Series J warrant liability at issuance		(165,820	)
	Repayment of January 23, 2013 Notes		(450,000	)
	Conversion of January 23, 2013 Notes into common stock		(100,000	)
	Conversion of July 25, 2012 Notes into common stock		(900,000	)
	Conversion of July 25, 2012 Notes into common stock		(2,555,000	)
	Unamortized discount closed to loss on debt extinguishment		1,949,003
	Amortization of debt discount to interest expense through September 30, 2013		1,473,168
	Balance at September 30, 2013	$	-

Related_Party_Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2013
Related Party Transactions	'
	Note 8.  Related Party Transactions
	Investors in the January 2013 Note offering included one member of Opexa’s Board of Directors who was issued a Note with a principal amount of $100,000 (see Note 7).
	Investors in the July 2012 Notes included two members of Opexa’s Board of Directors and an entity for which a third director reports beneficial ownership of Opexa securities, and Notes in the aggregate principal amount of $630,000 held by these directors and entity were outstanding at the time of the July 2012 Note Amendment (see Note 7).  On September 24, 2013, such post-modification Notes in an aggregate of $647,605 in principal amount and unpaid interest were converted into an aggregate of 339,170 shares of common stock at a conversion price of $1.91, which was the most recent closing market price of the Company’s common stock on the NASDAQ Stock Market when the Company effected such conversion.
	The following table provides a summary of the changes in convertible debt – related parties, net of unamortized discount, during the nine months ended September 30, 2013:
	Balance at December 31, 2012	$	58,105
	January 2013 Notes, face value		100,000
	Discount on beneficial conversion feature of January 2013 Notes at issuance		(21,820	)
	Discount on fair value of Series J warrant liability at issuance		(30,149	)
	Repayment of January 23, 2013 Notes		(100,000	)
	Conversion of July 25, 2012 Notes into common stock		(630,000	)
	Unamortized debt discount closed to loss on debt extinguishment		483,678
	Amortization of debt discount to interest expense through September 30, 2013		140,186
	Balance at September 30, 2013	$	-

Equity

Equity	9 Months Ended
	Sep. 30, 2013
Equity	'
	Note 9.  Equity
	For the nine months ended September 30, 2013, equity related transactions were as follows:
	●	In January 2013, 125,000 shares of common stock were sold and 975 additional commitment shares were issued to Lincoln Park under the $1.5 million purchase agreement for net proceeds of $142,400.
	●	In February 2013, 365,263 shares of common stock were issued in connection with the conversion of the January 2013 Notes and certain July 2012 Notes (see Note 7).
	●	In February 2013, Opexa sold an aggregate of 167,618 shares of common stock under the ATM Agreement for gross proceeds of $536,417.
	●	On February 11, 2013, Opexa sold an aggregate of 1,083,334 units in a registered offering, with each unit consisting of one share of common stock and a warrant to purchase half (0.5) a share of common stock, at a price of $3.00 per unit, for gross proceeds of $3,250,002. The shares of common stock and warrants were immediately separable and were issued separately such that no units were issued. The warrants are exercisable immediately upon issuance, have a four-year term and an exercise price of $3.00 per share. A fee of 6.0% of the gross proceeds was paid to the placement agent.
	●	On July 1, 2013, Opexa issued 123,231 shares of common stock to the Noteholders of the July 2012 Notes as payment of accrued interest through June 30, 2013.
	●	On August 13, 2013, Opexa sold 12,000,000 shares of common stock in an underwritten public offering at a price of $1.50 per share for gross proceeds of $18,000,000.
	●	In September 2013, exercise of the over-allotment option granted to the underwriters of the August 2013 underwritten public offering resulted in the issuance of an additional 900,000 shares of common stock at a price of $1.50 per share for gross proceeds of $1,350,000.
	●	On September 24, 2013, 1,714,697 shares of common stock were issued in connection with the conversion of the remaining outstanding July 2012 Notes (see Note 7).
	For the nine months ended September 30, 2013, $2,256,549 was netted against additional paid in capital as stock offering costs.

StockBased_Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2013
Stock-Based Compensation	'
	Note 10.  Stock-Based Compensation
	Stock Options
	The 2010 Stock Incentive Plan (the “2010 Plan”) provides for the grant of equity incentive awards to employees, directors and consultants of Opexa in the form of incentive stock options or nonqualified stock options, as well as restricted stock, stock appreciation rights, restricted stock units and performance awards that may be settled in cash, stock or other property.  The 2010 Plan is the successor to and continuation of Opexa’s June 2004 Compensatory Stock Option Plan (the “2004 Plan”). A total of 625,000 shares of common stock are authorized to be issued for awards made under the 2010 Plan through September 2020, plus (i) the number of shares subject to stock options outstanding under the 2004 Plan that are forfeited or terminate prior to exercise and would otherwise be returned to the share reserves under the 2004 Plan and (ii) any reserved shares under the 2004 Plan that were not issued or subject to outstanding grants.  In addition, shares subject to awards granted under the 2010 Plan that terminate or expire before being exercised or settled will become available for grant under the 2010 Plan. As of September 30, 2013, options to purchase an aggregate of 1,094,854 shares were issued and outstanding.
	Opexa accounts for share-based compensation, including options and nonvested shares, according to the provisions of Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) 718, "Share Based Payment.” During the nine months ended September 30, 2013, Opexa recognized option expense of $705,408. Unamortized stock compensation expense as of September 30, 2013 amounted to $970,912.
	Stock Option Activity
	A summary of stock option activity for the nine months ended September 30, 2013 is presented below:
		Number of			Wtd. Avg.		Wtd. Avg.		Intrinsic
		Shares			Exercise Price		Remaining		Value
							Contract Term
							(# years)
	Outstanding at January 1, 2013		824,620		$	5.54
	Granted		342,572			1.96
	Exercised		-			-
	Forfeited and canceled		(72,338	)		5.19
	Outstanding at September 30, 2013		1,094,854		$	4.45		7.7	$	184,740
	Exercisable at September 30, 2013		599,188		$	5.78		6.6	$	109,111
	Option awards are granted with an exercise price equal to the market price of Opexa’s stock at the date of issuance, generally have a ten-year life, and have various vesting dates that range from no vesting or partial vesting upon date of grant to full vesting on a specified date. Opexa estimates the fair value of stock options using the Black-Scholes option-pricing model and records the compensation expense ratably over the service period.
	During the nine months ended September 30, 2013, an option to purchase an aggregate of 125,000 shares was granted to an employee at an exercise price of $2.34. This option has a term of ten years and has a vesting schedule of three years. Fair value of $285,226 was calculated using the Black-Scholes option-pricing model. Variables used in the Black-Scholes option-pricing model for the option issued to an employee during the nine months ended September 30, 2013 include (1) discount rate of 1.87%, (2) expected term of 5.25 years, (3) expected volatility of 194% and (4) zero expected dividends.
	During the nine months ended September 30, 2013, options to purchase an aggregate of 129,000 shares were granted to employees at exercise prices ranging from $1.45 to $1.75. These options have terms of ten years and have vesting schedules of three years. Fair value of $218,348 was calculated using the Black-Scholes option-pricing model. Variables used in the Black-Scholes option-pricing model for the options issued to employees during the nine months ended September 30, 2013 include (1) discount rate range of 1.73% to 2.78%, (2) expected term of 5.25 years, (3) expected volatility of 201% to 204% and (4) zero expected dividends.
	During the nine months ended September 30, 2013, options to purchase an aggregate of 88,572 shares were granted to non-employee directors at an exercise price of $1.75. These options have terms of ten years with 50% of the options issued vesting immediately and the remaining 50% of the options issued having vesting schedules of eight months to one year. Fair value of $151,867 was calculated using the Black-Scholes option-pricing model. Variables used in the Black-Scholes option-pricing model for the options issued to non-employee directors during the nine months ended September 30, 2013 include (1) discount rate of 1.73%, (2) expected term of 5.25 years, (3) expected volatility of 201% and (4) zero expected dividends.
	During the nine months ended September 30, 2013, options to purchase 72,338 shares were forfeited and cancelled.
	Warrant Activity
	A summary of warrant activity for the nine months ended September 30, 2013 is presented below:
		Number of			Wtd. Avg.		Wtd. Avg.		Intrinsic Value
		Shares			Exercise Price		Remaining
							Contract Term
							(# years)
	Outstanding at January 1, 2013		3,579,087		$	5.64
	Granted		972,918			2.21
	Exercised		-			-
	Forfeited and canceled		(1,482,892	)		6.54
	Outstanding at September 30, 2013		3,069,113		$	4.12		3.4	$	415,313
	Exercisable at September 30, 2013		3,069,113		$	4.12		3.4	$	415,313
	In connection with the January 2013 Notes, investors were issued five-year warrants to purchase up to an aggregate of 243,750 shares of common stock, at an exercise price of $1.24 per share. The estimated relative fair value of the investor warrants was $195,969 and was calculated using the Black-Scholes valuation model. The following assumptions were used: (1) no expected dividends, (2) risk free interest rate of 0.76%, (3) expected volatility of 191% and (4) expected life of five years. Opexa can redeem the warrants at $0.01 per share if the Company’s common stock closes at or above $10.00 per share for 20 consecutive trading days.
	Pursuant to a waiver executed by the holders of in excess of two-thirds (66-2/3%) of the principal amount of the outstanding July 2012 Notes and accepted by Opexa, the original amount of the cash subject to the deposit control agreement was reduced to $500,000 on January 29, 2013.  In exchange for such waiver, the Company issued warrants to the holders of the July 2012 Notes to purchase an aggregate of 187,500 shares of the Company’s common stock.  The warrants have an exercise price of $1.21 per share and a five-year term.  The estimated fair value of the warrants was $219,553 and was calculated using the Black-Scholes valuation model.  The following assumptions were used: (1) no expected dividends, (2) risk free interest rate of 0.90%, (3) expected volatility of 191% and (4) expected life of five years.  Opexa can redeem the warrants at $0.01 per underlying share of common stock if the common stock closes at or above $10.00 per share for 20 consecutive trading days.  The fair value of the warrants was recognized as additional interest expense during the nine months ended September 30, 2013.
	In connection with the February 2013 registered offering (See Note 9), Opexa issued warrants to the investors on February 11, 2013 to purchase an aggregate of 541,668 shares of common stock at an exercise price of $3.00 per share. These warrants have a term of four years and were immediately exercisable.
	During the nine months ended September 30, 2013, warrants to purchase 1,482,892 shares were forfeited and cancelled.

Significant_Accounting_Polices1

Significant Accounting Polices (Policies)	9 Months Ended
	Sep. 30, 2013
Revenue Recognition	'
	Revenue Recognition.  Opexa recognizes revenue in accordance with FASB ASC 605, Revenue Recognition. ASC 605 requires that four basic criteria must be met before revenue can be recognized: (1) persuasive evidence of an arrangement exists; (2) delivery has occurred or services rendered; (3) consideration is fixed or determinable; and (4) collectability is reasonably assured.
	On February 4, 2013, Opexa entered into an Option and License Agreement (the “Merck Agreement”) with Ares Trading SA (“Merck”), a wholly owned subsidiary of Merck Serono S.A.  Pursuant to the terms, Merck has an option to acquire an exclusive, worldwide (excluding Japan) license of the Company’s Tcelna® program for the treatment of multiple sclerosis (“MS”).  Tcelna is currently in a Phase IIb clinical trial in patients with Secondary Progressive MS (“SPMS”). The option may be exercised by Merck prior to or upon the Company’s completion of the Phase IIb Trial.
	Opexa received an upfront payment of $5 million for granting the option. If the option is exercised, Merck would pay the Company an upfront license fee of $25 million unless Merck is unable to advance directly into a Phase III clinical trial of Tcelna for SPMS without a further Phase II clinical trial (as determined by Merck), in which event the upfront license fee would be $15 million. After exercising the option, Merck would be solely responsible for funding development, regulatory and commercialization activities for Tcelna in MS, although the Company would retain an option to co-fund certain development in exchange for increased royalty rates.  The Company would also retain rights to Tcelna in Japan, certain rights with respect to the manufacture of Tcelna, and rights outside of MS.
	Opexa evaluated the Merck Agreement and determined that the $5 million upfront payment from Merck has stand-alone value. Opexa’s continuing performance obligations, in connection with the $5 million payment, include the execution and completion of the Phase IIb clinical trial in SPMS using commercially reasonable efforts at the Company’s own costs.  As a stand-alone value term in the Merck Agreement, the $5 million upfront payment is determined to be a single unit of accounting, and is recognized as revenue on a straight-line basis over the exclusive option period based on the expected completion term of the Phase IIb clinical trial in SPMS. Opexa includes the unrecognized portion of the $5 million as deferred revenue on the consolidated balance sheets.
Cash and Cash Equivalents	'
	Cash and Cash Equivalents.  Opexa considers all highly liquid investments with an original maturity of three months or less, when purchased, to be cash equivalents. Investments with maturities in excess of three months but less than one year are classified as short-term investments and are stated at fair market value.
	Opexa primarily maintains cash balances on deposit in accounts at a U.S.-based financial institution.  The aggregate cash balance on deposit in these accounts is insured by the Federal Deposit Insurance Corporation up to $250,000.  Opexa’s cash balances on deposit in these accounts may, at times, exceed the federally insured limits.  Opexa has not experienced any losses in such accounts.
	At September 30, 2013, Opexa invested approximately $19.1 million in a savings account.  For the nine months ended September 30, 2013, the savings account recognized an average market yield of 0.19%.  Interest income of $9,388 was recognized for the nine months ended September 30, 2013 in the consolidated statements of operations.

Other_Current_Assets_Tables

Other Current Assets (Tables)	9 Months Ended
	Sep. 30, 2013
Other Current Assets	'
	Other current assets consisted of the following at September 30, 2013 and December 31, 2012:
	Description	September 30,		December 31,
		2013		2012
	Supplies inventory	$	803,371	$	604,179
	Deferred offering costs		326,630		341,166
	Prepaid expenses		174,145		132,201
		$	1,304,146	$	1,077,546

Related_Party_Transactions_Tab

Related Party Transactions (Tables)	9 Months Ended
	Sep. 30, 2013
Third Parties	'
Summary of Changes in Convertible Debt - Net of Unamortized Discount	'
	The following table provides a summary of the changes in convertible debt – third parties, net of unamortized discount, during the nine months ended September 30, 2013:
	Balance at December 31, 2012	$	318,658
	January 2013 Notes, face value		550,000
	Discount on beneficial conversion feature of January 2013 Notes at issuance		(120,009	)
	Discount on fair value of Series J warrant liability at issuance		(165,820	)
	Repayment of January 23, 2013 Notes		(450,000	)
	Conversion of January 23, 2013 Notes into common stock		(100,000	)
	Conversion of July 25, 2012 Notes into common stock		(900,000	)
	Conversion of July 25, 2012 Notes into common stock		(2,555,000	)
	Unamortized discount closed to loss on debt extinguishment		1,949,003
	Amortization of debt discount to interest expense through September 30, 2013		1,473,168
	Balance at September 30, 2013	$	-
Related Party Transactions	'
Summary of Changes in Convertible Debt - Net of Unamortized Discount	'
	The following table provides a summary of the changes in convertible debt – related parties, net of unamortized discount, during the nine months ended September 30, 2013:
	Balance at December 31, 2012	$	58,105
	January 2013 Notes, face value		100,000
	Discount on beneficial conversion feature of January 2013 Notes at issuance		(21,820	)
	Discount on fair value of Series J warrant liability at issuance		(30,149	)
	Repayment of January 23, 2013 Notes		(100,000	)
	Conversion of July 25, 2012 Notes into common stock		(630,000	)
	Unamortized debt discount closed to loss on debt extinguishment		483,678
	Amortization of debt discount to interest expense through September 30, 2013		140,186
	Balance at September 30, 2013	$	-

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2013
Stock Option Activity	'
	A summary of stock option activity for the nine months ended September 30, 2013 is presented below:
		Number of			Wtd. Avg.		Wtd. Avg.		Intrinsic
		Shares			Exercise Price		Remaining		Value
							Contract Term
							(# years)
	Outstanding at January 1, 2013		824,620		$	5.54
	Granted		342,572			1.96
	Exercised		-			-
	Forfeited and canceled		(72,338	)		5.19
	Outstanding at September 30, 2013		1,094,854		$	4.45		7.7	$	184,740
	Exercisable at September 30, 2013		599,188		$	5.78		6.6	$	109,111
Warrant Activity	'
	A summary of warrant activity for the nine months ended September 30, 2013 is presented below:
		Number of			Wtd. Avg.		Wtd. Avg.		Intrinsic Value
		Shares			Exercise Price		Remaining
							Contract Term
							(# years)
	Outstanding at January 1, 2013		3,579,087		$	5.64
	Granted		972,918			2.21
	Exercised		-			-
	Forfeited and canceled		(1,482,892	)		6.54
	Outstanding at September 30, 2013		3,069,113		$	4.12		3.4	$	415,313
	Exercisable at September 30, 2013		3,069,113		$	4.12		3.4	$	415,313

Significant_Accounting_Policie

Significant Accounting Policies - Additional Information (Detail) (USD $)	3 Months Ended	9 Months Ended	128 Months Ended
	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013
Summary Of Significant Accounting Policies [Line Items]	'	'	'
Option and License Agreement, upfront payment recognized	$348,837	$917,774	$917,774
Investment in savings account	19,100,000	19,100,000	19,100,000
Percentage of interest recognized from savings account investment	0.19%	0.19%	0.19%
Interest income from savings account investment	'	9,388	'
Maximum	'	'	'
Summary Of Significant Accounting Policies [Line Items]	'	'	'
Deposit insured by the Federal Deposit Insurance Corporation	250,000	250,000	250,000
Option and License Agreement	'	'	'
Summary Of Significant Accounting Policies [Line Items]	'	'	'
Option and License Agreement, upfront payment received	5,000,000	5,000,000	5,000,000
Licensing milestone	25,000,000	25,000,000	25,000,000
Option and License Agreement, upfront payment recognized	'	5,000,000	'
Option and License Agreement, deferred revenue	5,000,000	5,000,000	5,000,000
Option and License Agreement | Licensing fee if Merck is unable to advance directly to Phase III trials of Tcelna	'	'	'
Summary Of Significant Accounting Policies [Line Items]	'	'	'
Licensing milestone	$15,000,000	$15,000,000	$15,000,000

Other_Current_Assets_Detail

Other Current Assets (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Other Assets, Current [Line Items]	'	'
Supplies inventory	$803,371	$604,179
Deferred offering costs	326,630	341,166
Prepaid expenses	174,145	132,201
Other current assets	$1,304,146	$1,077,546

Other_Current_Assets_Additiona

Other Current Assets - Additional Information (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2013	Jan. 31, 2013	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013
			Other Current Assets	$1.5 Million Purchase Agreement with Lincoln Park	$1.5 Million Purchase Agreement with Lincoln Park	$15 Million Purchase Agreement with Lincoln Park	ATM Agreement	Purchase Agreements
							Third Party	Other Current Assets
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Line Items]	'	'	'	'	'	'	'	'
Deferred financing cost	$326,630	$341,166	'	'	'	'	$88,446	$238,184
Purchase agreement, aggregate shares opexa has right to sell	16,500,000	'	'	1,500,000	1,500,000	15,000,000	'	'
Legal costs, current	'	'	$44,070	'	'	'	'	'

Restricted_Cash_Additional_Inf

Restricted Cash - Additional Information (Detail) (USD $)	9 Months Ended
	Sep. 30, 2013	Sep. 24, 2013	Jan. 31, 2013	Jan. 29, 2013	Jan. 23, 2013	Dec. 31, 2012	Sep. 30, 2012	Dec. 31, 2011
Restricted Cash and Cash Equivalents Items [Line Items]	'	'	'	'	'	'	'	'
Restricted cash	'	'	'	$500,000	'	$1,000,000	'	'
Percentage needed to effect the waiver on the restricted cash	66.67%	'	'	'	'	'	'	'
Warrants issued to purchase common stock	'	'	243,750	187,500	243,750	'	'	'
Cash and cash equivalents	$20,172,485	$500,000	'	'	'	$592,004	$2,237,618	$7,109,215
Convertible debt	'	'	'	'	'	'	'	'
Restricted Cash and Cash Equivalents Items [Line Items]	'	'	'	'	'	'	'	'
Convertible debt instrument, effective interest rate	'	12.00%	'	'	12.00%	'	'	'

Deferred_Financing_Costs_Addit

Deferred Financing Costs - Additional Information (Detail) (USD $)	3 Months Ended	9 Months Ended		128 Months Ended
	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Line Items]	'	'	'	'
Loss on debt extinguishment	($2,518,912)	($2,518,912)	'	($906,472)
Deferred financing costs, amortized	'	125,248	24,710	708,265
Deferred Financing Costs	'	'	'	'
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Line Items]	'	'	'	'
Loss on debt extinguishment	-86,231	-86,231	'	'
Deferred financing costs, amortized	'	$125,248	'	'

Other_Assets_Additional_Inform

Other Assets - Additional Information (Detail) (USD $)	9 Months Ended
	Sep. 30, 2013
General and Administrative Expense	'
Schedule of Other Assets [Line Items]	'
Legal costs, amortized	$28,799
Other Current Assets	'
Schedule of Other Assets [Line Items]	'
Legal costs, current	44,070
Other Long-term Assets	'
Schedule of Other Assets [Line Items]	'
Legal costs, long-term	$85,047

Convertible_Promissory_Notes_A

Convertible Promissory Notes - Additional Information (Detail) (USD $)

1 Months Ended

3 Months Ended

9 Months Ended

128 Months Ended

1 Months Ended

9 Months Ended

1 Months Ended

9 Months Ended

1 Months Ended

9 Months Ended

1 Months Ended

1 Months Ended

9 Months Ended

1 Months Ended

1 Months Ended

Sep. 24, 2013

Jun. 30, 2013

Jan. 31, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Jan. 29, 2013

Jan. 23, 2013

Dec. 31, 2012

Sep. 24, 2013

Sep. 30, 2013

Feb. 28, 2013

Sep. 30, 2013

Feb. 28, 2013

Sep. 30, 2013

Feb. 28, 2013

Sep. 24, 2013

Sep. 23, 2013

Sep. 24, 2013

Sep. 23, 2013

Sep. 23, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Jul. 31, 2012

Feb. 28, 2013

Jan. 23, 2013

Sep. 24, 2013

Feb. 28, 2013

Jan. 23, 2013

July 2012 Notes

July 2012 Notes

Common Stock

Common Stock

January 2013 Notes

January 2013 Notes

January 2013 Notes

Amendment

Amendment

Amendment

Amendment

Amendment

Option and License Agreement

Related Party

Related Party Transactions

Related Party Transactions

Convertible debt

Convertible debt

Convertible debt

Convertible debt

Convertible debt

Common Stock

July 2012 Notes

July 2012 Notes

Common Stock

Minimum

Maximum

Common Stock

Related Party

July 2012 Notes

July 2012 Notes

July 2012 Notes

Debt Instrument [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Gross proceed from the issuance of convertible note

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$650,000

'

'

$100,000

Debt Instrument, Maturity Date

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

23-Jan-14

'

'

'

Convertible debt instrument, effective interest rate

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

12.00%

12.00%

'

'

Convertible debt, conversion price

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$1.91

'

'

$1.50

$2.25

'

'

'

$1.91

'

$1.30

'

'

'

Minimum receipt of proceeds from sale of equity securities and/or as payments from partners to pay any remaining balance of note payable

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

7,500,000

'

'

'

Number of business days to pay remaining convertible debts

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'5 days

'

'

'

Debt instrument, beneficial conversion feature

'

'

141,829

'

141,829

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

21,820

'

'

'

'

'

'

Discount on warrant

'

'

195,969

'

195,969

2,314,635

6,170,341

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Warrants issued

'

'

243,750

'

'

'

'

187,500

243,750

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Gross proceeds from sales of common stock and warrants to purchase shares of common stock

'

'

'

'

3,250,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Option and License Agreement, upfront payment received

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

5,000,000

'

'

'

'

'

'

'

'

Principal and interest paid

'

'

'

'

567,368

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

100,000

'

'

'

'

'

'

'

Common shares issued, note conversion

1,714,697

'

'

'

'

'

'

'

'

'

'

'

365,263

2,079,960

'

'

77,034

'

'

1,714,697

'

'

'

'

'

'

'

'

'

'

'

Convertible notes, principal amount converted

'

'

'

'

'

'

'

'

'

'

'

900,000

'

'

100,000

'

'

'

'

'

'

'

'

'

'

'

900,000

'

'

'

'

Amortization of debt discount to interest expense

'

'

'

'

1,613,354

34,600

8,470,084

'

'

'

'

'

'

'

'

337,798

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Common shares issued

'

123,231

'

'

900,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

288,229

'

Aggregate principal amount outstanding

'

'

'

'

'

'

'

'

'

'

756,141

'

'

'

'

'

'

'

3,185,000

'

'

'

'

'

'

'

'

'

'

'

'

Conversion of convertible notes

'

'

'

'

4,275,053

'

'

'

'

'

'

'

'

20,799

'

'

'

3,275,053

'

'

'

'

'

'

'

'

'

'

'

'

'

Loss on extinguishment of debt

'

'

'

-2,518,912

-2,518,912

'

-906,472

'

'

'

-2,518,912

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Accrued interest

'

'

'

'

'

'

'

'

'

'

98,053

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Unamortized debt discount

'

'

'

'

'

'

'

'

'

'

2,432,681

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Unamortized deferred financing cost

'

'

'

'

'

'

'

'

'

$211,479

$86,231

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Summary_of_Changes_in_Converti

Summary of Changes in Convertible Debt Third Parties Net of Unamortized Discount (Detail) (USD $)	9 Months Ended		128 Months Ended		9 Months Ended			9 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013	Sep. 24, 2013	Sep. 30, 2013
				Warrants Attached to Debt	Convertible debt	January 2013 Notes	January 2013 Notes	July 2012 Notes	July 2012 Notes	July 2012 Notes
							Beneficial Conversion Feature			Scenario Two
Debt Instrument [Line Items]	'	'	'	'	'	'	'	'	'	'
Balance at December 31, 2012	$318,658	'	'	'	'	'	'	'	'	'
Notes, face value	'	'	'	'	'	550,000	'	'	'	'
Discount on convertible debt	'	'	'	-165,820	'	'	-120,009	'	-2,432,681	'
Repayment of January 23, 2013 Notes	-450,000	'	-761,222	'	'	-450,000	'	'	'	'
Principal amount of Notes converted to common stock	'	'	'	'	'	-100,000	'	-900,000	'	-2,555,000
Unamortized discount closed to loss on debt extinguishment	1,949,003	'	'	'	'	'	'	'	'	'
Amortization of debt discount to interest expense through September 30, 2013	($1,613,354)	($34,600)	($8,470,084)	'	$1,473,168	'	'	'	'	'

Related_Party_Transactions_Add

Related Party Transactions - Additional Information (Detail) (Related Party Transactions, USD $)	1 Months Ended
	Sep. 24, 2013	Jan. 31, 2013	Jul. 31, 2012
Related Party Transactions	'	'	'
Related Party Transaction [Line Items]	'	'	'
Convertible secured promissory notes, principal amount	$647,605	$100,000	$630,000
Number of common stock issued upon conversion of notes	339,170	'	'
Conversion price	'	'	$1.91

Summary_of_Changes_in_Converti1

Summary of Changes in Convertible Debt Related Parties Net of Unamortized Discount (Detail) (USD $)	9 Months Ended		128 Months Ended				9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013
				Warrants Attached to Debt	Related Party Transactions	Related Party Transactions	Convertible debt	Convertible debt	Convertible debt	Convertible debt
							Related Party Transactions	Related Party Transactions	Related Party Transactions	Related Party Transactions
								July 2012 Notes	Beneficial Conversion Feature	Warrants Attached to Debt
Debt Instrument [Line Items]	'	'	'	'	'	'	'	'	'	'
Balance at December 31, 2012	$318,658	'	'	'	'	'	$58,105	'	'	'
Notes, face value	'	'	'	'	'	'	100,000	'	'	'
Discount on convertible debt	'	'	'	-165,820	0	-571,895	'	'	-21,820	-30,149
Repayment of January 23, 2013 Notes	-450,000	'	-761,222	'	'	'	-100,000	'	'	'
Principal amount of Notes converted to common stock	'	'	'	'	'	'	'	-630,000	'	'
Unamortized debt discount closed to loss on debt extinguishment	1,949,003	'	'	'	'	'	483,678	'	'	'
Amortization of debt discount to interest expense through September 30, 2013	($1,613,354)	($34,600)	($8,470,084)	'	'	'	$140,186	'	'	'

Equity_Additional_Information_

Equity - Additional Information (Detail) (USD $)

1 Months Ended

9 Months Ended

128 Months Ended

1 Months Ended

9 Months Ended

1 Months Ended

1 Months Ended

Sep. 24, 2013

Jun. 30, 2013

Feb. 11, 2013

Jan. 23, 2013

Jan. 29, 2013

Sep. 30, 2013

Sep. 30, 2013

Feb. 28, 2013

Sep. 30, 2013

Aug. 13, 2013

Feb. 28, 2013

Sep. 30, 2013

Jan. 31, 2013

Jan. 31, 2013

Common Stock

Common Stock

Public Offering

ATM Agreement

$1.5 Million Purchase Agreement with Lincoln Park

$1.5 Million Purchase Agreement with Lincoln Park

$1.5 Million Purchase Agreement with Lincoln Park

Common Stock

Equity Note [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Common shares issued

'

123,231

'

'

'

900,000

'

'

'

12,000,000

167,618

'

'

125,000

Purchase agreement, aggregate shares opexa has right to sell

'

'

'

'

'

$16,500,000

$16,500,000

'

'

'

'

$1,500,000

$1,500,000

'

Net proceeds from shares sold

'

'

'

'

'

'

'

'

'

'

536,417

'

'

142,400

Common stock issued as fee

'

'

'

'

'

'

'

'

'

'

'

'

'

975

Common shares issued, note conversion

1,714,697

'

'

'

'

'

'

365,263

2,079,960

'

'

'

'

'

Common shares issued

'

'

1,083,334

'

'

'

'

'

'

'

'

'

'

'

Warrants settlement ratio

'

'

'Each unit consisting of one share of common stock and a warrant to purchase half (0.5) a share of common stock

'

'

'

'

'

'

'

'

'

'

'

Share issue to private offering, price per share

'

'

$3

'

'

$1.50

'

'

'

$1.50

'

'

'

'

Proceeds from issuance of common stocks and warrants, net

'

'

3,250,002

'

'

21,319,153

70,772,950

'

'

'

'

'

'

'

Warrant term

'

'

'4 years

'5 years

'5 years

'

'

'

'

'

'

'

'

'

Warrant exercise price

'

'

$3

$1.24

$1.21

'

'

'

'

'

'

'

'

'

Commission rate on gross proceed for common stock sold

'

'

6.00%

'

'

'

'

'

'

'

'

'

'

'

Gross proceeds from shares of common stock sold

'

'

'

'

'

1,350,000

'

'

'

18,000,000

'

'

'

'

Amount netted against additional paid in capital as stock offering costs

'

'

'

'

'

$2,256,549

'

'

'

'

'

'

'

'

StockBased_Compensation_Additi

Stock-Based Compensation - Additional Information (Detail) (USD $)	1 Months Ended			9 Months Ended
	Feb. 11, 2013	Jan. 23, 2013	Jan. 29, 2013	Sep. 30, 2013	Jan. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'	'
Share based compensation, common stock shares issued and outstanding	'	'	'	1,094,854	'	824,620
Option expense recognized	'	'	'	$705,408	'	'
Unamortized stock compensation expense	'	'	'	970,912	'	'
Number of Shares, Granted	'	'	'	342,572	'	'
Expected dividends	'	'	'	0	'	'
Number of Shares, Forfeited and canceled	'	'	'	72,338	'	'
Warrant term	'4 years	'5 years	'5 years	'	'	'
Warrants issued to purchase common stock	'	243,750	187,500	'	243,750	'
Warrant exercise price	$3	$1.24	$1.21	'	'	'
Warrant redemption price per share	'	$0.01	$0.01	'	'	'
Terms for warrant redeem	'	'Opexa can redeem the warrants at $0.01 per share if the Company's common stock closes at or above $10.00 per share for 20 consecutive trading days.	'The warrants at $0.01 per underlying share of common stock if the common stock closes at or above $10.00 per share for 20 consecutive trading days.	'	'	'
Number of common stock to be issued upon exercise of warrant	541,668	'	187,500	'	'	'
Warrants Attached to Debt	'	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'	'
Discount rate	'	0.76%	'	'	'	'
Expected life	'	'5 years	'	'	'	'
Expected volatility rate	'	191.00%	'	'	'	'
Expected dividends	'	0	'	'	'	'
Estimated fair value of warrants	'	195,969	'	'	'	'
Warrants, Forfeited and canceled	'	'	'	1,482,892	'	'
Common Stock Warrants issued to Release a Claim on Cash	'	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'	'
Discount rate	'	'	0.90%	'	'	'
Expected life	'	'	'5 years	'	'	'
Expected volatility rate	'	'	191.00%	'	'	'
Estimated fair value of warrants	'	'	219,553	'	'	'
Employee Stock Option	'	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'	'
Stock option, term	'	'	'	'10 years	'	'
Employee Stock Option | Employee	'	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'	'
Stock option, term	'	'	'	'10 years	'	'
Number of Shares, Granted	'	'	'	125,000	'	'
Weighted average exercise price, Granted	'	'	'	$2.34	'	'
Vesting period	'	'	'	'3 years	'	'
Fair value of stock granted during period	'	'	'	285,226	'	'
Discount rate	'	'	'	1.87%	'	'
Expected life	'	'	'	'5 years 3 months	'	'
Expected volatility rate	'	'	'	194.00%	'	'
Expected dividends	'	'	'	0	'	'
Employee Stock Option | Employees	'	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'	'
Stock option, term	'	'	'	'10 years	'	'
Number of Shares, Granted	'	'	'	129,000	'	'
Vesting period	'	'	'	'3 years	'	'
Fair value of stock granted during period	'	'	'	218,348	'	'
Expected life	'	'	'	'5 years 3 months	'	'
Expected dividends	'	'	'	$0	'	'
Employee Stock Option | Employees | Minimum	'	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'	'
Weighted average exercise price, Granted	'	'	'	$1.45	'	'
Discount rate	'	'	'	1.73%	'	'
Expected volatility rate	'	'	'	201.00%	'	'
Employee Stock Option | Employees | Maximum	'	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'	'
Weighted average exercise price, Granted	'	'	'	$1.75	'	'
Discount rate	'	'	'	2.78%	'	'
Expected volatility rate	'	'	'	204.00%	'	'
Non Employee Director Stock Option	'	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'	'
Stock option, term	'	'	'	'10 years	'	'
Number of Shares, Granted	'	'	'	88,572	'	'
Weighted average exercise price, Granted	'	'	'	$1.75	'	'
Discount rate	'	'	'	1.73%	'	'
Expected life	'	'	'	'5 years 3 months	'	'
Expected volatility rate	'	'	'	201.00%	'	'
Fair value stock granted during period	'	'	'	$151,867	'	'
Stock options vesting percentage, immediately from date of grant	'	'	'	50.00%	'	'
Stock options vesting percentage, remaining of period	'	'	'	50.00%	'	'
Non Employee Director Stock Option | Minimum	'	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'	'
Vesting period	'	'	'	'8 months	'	'
Non Employee Director Stock Option | Maximum	'	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'	'
Vesting period	'	'	'	'1 year	'	'
2010 Plan	'	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'	'
Stock based compensation, common stock shares authorized	'	'	'	625,000	'	'
Share based compensation, common stock shares issued and outstanding	'	'	'	1,094,854	'	'

Stock_Option_Activity_Detail

Stock Option Activity (Detail) (USD $)	9 Months Ended
	Sep. 30, 2013
Number of Shares	'
Number of Shares, Outstanding at beginning of period	824,620
Number of Shares, Granted	342,572
Number of Shares, Exercised	'
Number of Shares, Forfeited and canceled	-72,338
Number of Shares, Outstanding at end of period	1,094,854
Number of Shares, Exercisable at end of period	599,188
Weighted average exercise price	'
Weighted average exercise price, Outstanding at beginning of period	$5.54
Weighted average exercise price, Granted	$1.96
Weighted average exercise price, Exercised	'
Weighted average exercise price, Forfeited and canceled	$5.19
Weighted average exercise price, Outstanding at end of period	$4.45
Weighted average exercise price, Exercisable at end of period	$5.78
Weighted average remaining contract term	'
Weighted average remaining contract term, Outstanding at end of period	'7 years 8 months 12 days
Weighted average remaining contract term, Exercisable at end of period	'6 years 7 months 6 days
Intrinsic Value	'
Intrinsic Value, Outstanding at end of period	$184,740
Intrinsic Value, Exercisable at end of period	$109,111

Warrant_Activity_Detail

Warrant Activity (Detail) (Warrants Attached to Debt, USD $)	9 Months Ended
	Sep. 30, 2013
Warrants Attached to Debt	'
Number of Shares	'
Number of Shares, Outstanding at beginning of period	3,579,087
Number of Shares, Granted	972,918
Number of Shares, Exercised	'
Number of Shares, Forfeited and canceled	-1,482,892
Number of Shares, Outstanding at end of period	3,069,113
Number of Shares, Exercisable at end of period	3,069,113
Weighted average exercise price	'
Weighted average exercise price, Outstanding at beginning of period	$5.64
Weighted average exercise price, Granted	$2.21
Weighted average exercise price, Exercised	'
Weighted average exercise price, Forfeited and canceled	$6.54
Weighted average exercise price, Outstanding at end of period	$4.12
Weighted average exercise price, Exercisable at end of period	$4.12
Weighted average remaining contract term	'
Weighted average remaining contract term, Outstanding at end of period	'3 years 4 months 24 days
Weighted average remaining contract term, Exercisable at end of period	'3 years 4 months 24 days
Intrinsic Value	'
Intrinsic Value, Outstanding at end of period	$415,313
Intrinsic Value, Exercisable at end of the period	$415,313