Aggregate offering price of common stock issuable under sales agreement.

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Date of reincorporation.

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Organization, consolidation and presentation of financial statement.

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Date when the business acquisition agreement was executed, in CCYY-MM-DD format.

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With respect to a business combination completed during the period, this element provides a description of the business, other than the name, which may include the industry, size, products and other important information.

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Date when the acquirer obtains control of the acquiree, in CCYY-MM-DD format.

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Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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Face amount or stated value per share of common stock.

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Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.

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Amount of cash inflow (outflow) from operating activities, including discontinued operations. Operating activity cash flows include transactions, adjustments, and changes in value not defined as investing or financing activities.

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Face amount per share of no-par value preferred stock nonredeemable or redeemable solely at the option of the issuer.

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Face amount or stated value per share of preferred stock nonredeemable or redeemable solely at the option of the issuer.

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Date the exit and disposal activities were completed or are expected to be completed, in CCYY-MM-DD format.

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The cumulative amount of the reporting entity's undistributed earnings or deficit.

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Ratio applied to the conversion of stock split, for example but not limited to, one share converted to two or two shares converted to one.

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Nature of Operations and Basis of Presentation - Additional Information (Details)			1 Months Ended	12 Months Ended
	Mar. 18, 2020 USD ($)	Sep. 19, 2017	Jun. 30, 2019 Employee	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares	May 15, 2018 $ / shares	May 14, 2018 $ / shares
Organization Consolidation and Presentation of Financial Statement [Line Items]
Restructuring implemented date				Jun. 30, 2019
Corporate restructuring, reduction of full-time workforce percentage			60.00%
Corporate restructuring, reduction of full-time workforce employees \| Employee			48
Restructuring completion date				Dec. 31, 2019
Preferred stock, no par value							$ 0
Preferred stock, par value				$ 0.0001	$ 0.0001
Common stock, par value				$ 0.0001	$ 0.0001		$ 0.01
Accumulated deficit \| $				$ 76,250,512	$ 46,832,543
Cash and cash equivalents \| $				12,077,640	41,671,284
Net cash used in operating activities \| $				$ 29,506,949	$ 16,587,803
Common stock, shares issued \| shares				10,095,176	10,087,363
At-the-Market Facility
Organization Consolidation and Presentation of Financial Statement [Line Items]
Common stock, shares issued \| shares				0
At-the-Market Facility \| Subsequent Event \| Maximum
Organization Consolidation and Presentation of Financial Statement [Line Items]
Aggregate offering price of common stock \| $	$ 50,000,000
Merger of Private Acer with opexa therapeutics incorporation and 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 Company’s 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