2. Significant Accounting Polices	3 Months Ended
Mar. 31, 2016
Accounting Policies [Abstract]
Significant Accounting Polices	Revenue Recognition. Opexa recognizes revenue in accordance with Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“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 Serono Agreement”) with Ares Trading SA (“Merck Serono”), a wholly owned subsidiary of Merck Serono S.A. Pursuant to the terms, Merck Serono has an option to acquire an exclusive, worldwide (excluding Japan) license of Opexa’s Tcelna® program for the treatment of multiple sclerosis (“MS”). Tcelna is currently in a Phase IIb clinical trial (“Abili-T”) in patients with Secondary Progressive MS (“SPMS”). The option may be exercised by Merck Serono prior to or upon Opexa’s completion of the Phase IIb Trial. Opexa received an upfront payment of $5 million for granting the option. Opexa recognized revenues from nonrefundable, up-front $5 million option fees related to the Merck Serono Agreement on a straight-line basis over the estimated option exercise period which coincides with the expected completion term of the Abili-T clinical trial in SPMS. If the option is exercised, Merck Serono would pay the Company an upfront license fee of $25 million unless Merck Serono 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 Serono), in which event the upfront license fee would be $15 million. After exercising the option, Merck Serono 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. On March 9, 2015 Opexa entered into a First Amendment of Option and License Agreement with Merck Serono, to amend the Merck Serono Agreement (the “Merck Serono Amendment”). Opexa received $3 million in consideration for the following: (i) Creating a detailed plan for potential Phase III development of Tcelna (the “Pre-Phase III Plan”), including documenting all of the activities necessary for laboratory facilities both in the U.S. and Europe to reach operational readiness by the end of December 2016. The Joint Steering Committee (“JSC”) established pursuant to the Merck Serono Agreement will be responsible for reviewing, approving and ultimately overseeing Opexa’s completion of the Pre-Phase III Plan. In the event the JSC has not approved the Pre-Phase III Plan prior to the end of the period in the Merck Serono Agreement within which Merck Serono may exercise its option, such period will be extended for 60 days following approval of the Pre Phase III Plan by the JSC. (ii) Providing Merck Serono with updates and analysis on a blinded basis, grouped in patient batches according to Opexa’s analysis timetable, on the progress of Opexa’s immune monitoring program being conducted in conjunction with the ongoing Abili-T clinical trial. Opexa evaluated the Merck Serono Amendment and determined that the $3 million payment from Merck Serono has stand-alone value. Opexa’s continuing performance obligations in connection with the $3 million payment include the creation of the Pre-Phase III Plan and delivery of updates and analysis relating to Opexa’s immune monitoring program. As a stand-alone value term in the Merck Serono Amendment, the $3 million payment is determined to be a single unit of accounting, and is recognized as revenue on a straight-line basis over the period equivalent to the expected completion of the Pre-Phase III Plan in December 2016. Opexa includes the unrecognized portion of the $5 million option payment and the $3 million amendment payment as deferred revenue on its 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. As of March 31, 2016, Opexa had approximately $9.3 million in a savings account. For the three months ended March 31, 2016, the savings account recognized an average market yield of 0.06%. Interest income of $1,479 was recognized for the three months ended March 31, 2016 in the consolidated statements of operations. Reclassifications. Certain reclassifications of prior year reported amounts have been made for comparative purposes. Opexa does not consider such reclassifications to be material and they had no effect on net income.

2. Significant Accounting Polices

3 Months Ended

Mar. 31, 2016

Revenue Recognition. Opexa recognizes revenue in accordance with Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“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 Serono Agreement”) with Ares Trading SA (“Merck Serono”), a wholly owned subsidiary of Merck Serono S.A. Pursuant to the terms, Merck Serono has an option to acquire an exclusive, worldwide (excluding Japan) license of Opexa’s Tcelna® program for the treatment of multiple sclerosis (“MS”). Tcelna is currently in a Phase IIb clinical trial (“Abili-T”) in patients with Secondary Progressive MS (“SPMS”). The option may be exercised by Merck Serono prior to or upon Opexa’s completion of the Phase IIb Trial.

Opexa received an upfront payment of $5 million for granting the option. Opexa recognized revenues from nonrefundable, up-front $5 million option fees related to the Merck Serono Agreement on a straight-line basis over the estimated option exercise period which coincides with the expected completion term of the Abili-T clinical trial in SPMS. If the option is exercised, Merck Serono would pay the Company an upfront license fee of $25 million unless Merck Serono 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 Serono), in which event the upfront license fee would be $15 million. After exercising the option, Merck Serono 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.

On March 9, 2015 Opexa entered into a First Amendment of Option and License Agreement with Merck Serono, to amend the Merck Serono Agreement (the “Merck Serono Amendment”). Opexa received $3 million in consideration for the following:

(i) Creating a detailed plan for potential Phase III development of Tcelna (the “Pre-Phase III Plan”), including documenting all of the activities necessary for laboratory facilities both in the U.S. and Europe to reach operational readiness by the end of December 2016. The Joint Steering Committee (“JSC”) established pursuant to the Merck Serono Agreement will be responsible for reviewing, approving and ultimately overseeing Opexa’s completion of the Pre-Phase III Plan. In the event the JSC has not approved the Pre-Phase III Plan prior to the end of the period in the Merck Serono Agreement within which Merck Serono may exercise its option, such period will be extended for 60 days following approval of the Pre Phase III Plan by the JSC.

(ii) Providing Merck Serono with updates and analysis on a blinded basis, grouped in patient batches according to Opexa’s analysis timetable, on the progress of Opexa’s immune monitoring program being conducted in conjunction with the ongoing Abili-T clinical trial.

Opexa evaluated the Merck Serono Amendment and determined that the $3 million payment from Merck Serono has stand-alone value. Opexa’s continuing performance obligations in connection with the $3 million payment include the creation of the Pre-Phase III Plan and delivery of updates and analysis relating to Opexa’s immune monitoring program. As a stand-alone value term in the Merck Serono Amendment, the $3 million payment is determined to be a single unit of accounting, and is recognized as revenue on a straight-line basis over the period equivalent to the expected completion of the Pre-Phase III Plan in December 2016. Opexa includes the unrecognized portion of the $5 million option payment and the $3 million amendment payment as deferred revenue on its 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.

As of March 31, 2016, Opexa had approximately $9.3 million in a savings account. For the three months ended March 31, 2016, the savings account recognized an average market yield of 0.06%. Interest income of $1,479 was recognized for the three months ended March 31, 2016 in the consolidated statements of operations.

Reclassifications. Certain reclassifications of prior year reported amounts have been made for comparative purposes. Opexa does not consider such reclassifications to be material and they had no effect on net income.