Merger Agreement	9 Months Ended
Sep. 30, 2019
Business Combinations [Abstract]
Merger Agreement	3. Merger Agreement Merger Agreement with NeuroBo On July 24, 2019, the Company entered into the Merger Agreement with NeuroBo pursuant to which, the Company’s wholly owned subsidiary, Merger Sub, will merge with and into NeuroBo, with NeuroBo surviving as a wholly owned subsidiary of the Company, in an all-stock transaction. Subject to the terms and conditions of the Merger Agreement, at the effective time of the Merger (the “Effective Time”), (a) each share of NeuroBo common stock outstanding immediately prior to the Effective Time (excluding shares held as treasury stock, held by NeuroBo and dissenting shares) will be converted into the right to receive shares of Gemphire common stock equal to the Exchange Ratio described below; and (b) each outstanding NeuroBo stock option that has not previously been exercised prior to the Effective Time will be assumed by the Company. For accounting purposes, NeuroBo is considered to be acquiring the Company even though the Company will be the issuer of the common stock in the merger due to various considerations, including the expected ownership positions of Gemphire and NeuroBo post-merger. Substantially all the fair value of the Company is concentrated in one asset, in-process research and development IP, and therefore the merger is expected to be accounted for as an asset acquisition by NeuroBo. Under the exchange ratio formula in the Merger Agreement (the “Exchange Ratio”), upon the closing of the Merger, on a pro forma basis and based upon the number of shares of common stock expected to be issued in the Merger, former Company security holders immediately prior to the Merger are expected to own, or hold rights to acquire, approximately 3.74% of the combined company and former NeuroBo security holders immediately prior to the Merger are expected to own, or hold rights to acquire, approximately 96.26% of the combined company, on a fully-diluted basis and assuming that the Company has a net cash amount of negative $3,400,000 at closing and that NeuroBo raises the minimum required amount of $24,240,000 in its Series B Preferred Stock financing described below. The ownership percentages are subject to adjustment to the extent that the Company’s net cash at the Effective Time is negative or to reflect aggregate gross proceeds received by NeuroBo in its financing before the closing of the Merger above the minimum required amount and up to and including $50 million. Consummation of the Merger is subject to certain closing conditions, including, among other things, approval by the Company’s stockholders and NeuroBo’s stockholders, the continued listing of the common stock on the Nasdaq Capital Market, the conversion of all NeuroBo preferred stock and NeuroBo convertible notes into NeuroBo common stock and satisfaction by the Company of a minimum parent cash amount of negative $3.75 million at closing. Prior to signing the Merger Agreement, NeuroBo entered into subscription agreements with investors for a Series B Preferred Stock financing for approximate gross proceeds of $24,240,000, the minimum required amount under the Merger Agreement, and may enter into additional subscription agreements and receive additional proceeds between signing and closing of the Merger. The Merger Agreement contains certain termination rights for both the Company and NeuroBo, and further provides that, upon termination of the Merger Agreement under specified circumstances, either party may be required to pay the other party a termination fee of $1,000,000, or in some circumstances reimburse the other party’s expenses up to a maximum of $500,000. Following the closing of the Merger, it is expected that NeuroBo’s Chief Executive Officer, John L. Brooks III, will serve as Chief Executive Officer of the Company and the board of directors of the Company will be comprised of ten directors, consisting of nine directors designated by NeuroBo and Steven Gullans, the Company’s current President and Chief Executive Officer. In addition, upon completion of the merger, Gemphire will change its name to NeuroBo Pharmaceuticals, Inc., and plans to change its ticker symbol on the Nasdaq Capital Market to “NRBO”. The merged company will focus on the development of NeuroBo’s clinical-stage drug candidates for the treatment of neurodegenerative diseases. The Merger is expected to close in the fourth quarter of 2019, subject to approval by the Company’s stockholders at an annual meeting to be held on December 6, 2019 and other closing conditions. Contingent Value Rights Agreement At the Effective Time, the Company will enter into a Contingent Value Rights Agreement (the “CVR Agreement”). Pursuant to the Merger Agreement and the CVR Agreement, for each share of the Company’s common stock held, stockholders of record as of immediately prior to the Effective Time will receive one contingent value right (“CVR”) entitling such holders to receive in the aggregate, 80% of the Gross Consideration (as defined in the CVR Agreement which contemplates the post-Merger combined company’s prior retention of an aggregate of $500,000) less other Permitted Deductions (each as defined in the CVR Agreement) received during the 15-year period after the closing of the Merger (the “CVR Term”) from the grant, sale or transfer of rights to the Company’s product candidate gemcabene (other than a grant, sale or transfer of rights involving a sale or disposition of the post-Merger combined company) that is entered into during the 10-year period after the closing of the Merger or pursuant to the Beijing SL Agreement, but not including the $2.5 million non-refundable upfront gross payment pursuant to the Beijing SL Agreement, which was paid in October 2019. Under the CVR Agreement, the combined company agreed to commit $1 million to support the further development of gemcabene through the quarter ending March 31, 2020, the funding of which was conditioned on receipt by the Company of the $2.5 million non-refundable upfront gross payment payable under the Beijing SL Agreement. The CVRs are not transferable, except in certain limited circumstances, will not be certificated or evidenced by any instrument, will not accrue interest and will not be registered with the SEC or listed for trading on any exchange. The CVR Agreement will be effective prior to the closing of the Merger and will continue in effect until the later of the end of the CVR Term and the payment of all amounts payable thereunder, unless and until earlier terminated upon termination of the Merger Agreement. Change in Control Payments and Severance Awards On July 24, 2019, the Company entered into amendments to the employment agreements (the “Amendments”) of Dr. Steven Gullans, Chief Executive Officer and President, Dr. Charles Bisgaier, Chief Scientific Officer and Chairman of the board of directors, and Seth Reno, Chief Commercial Officer (the “Executives”) to reduce the cash severance obligation owed to each Executive in connection with the termination of their employment upon the closing of the Merger. Pursuant to the Amendments, if the Merger is completed, each of Dr. Gullans, Dr. Bisgaier and Mr. Reno will receive a lump sum cash payment within thirty days after the effective date of the Merger in an amount equal to $75,000, $330,000 and $297,536, respectively, subject to a reduction for withholding tax, in lieu of the cash compensation such Executives would otherwise be entitled to receive in connection with a termination following a change in control pursuant to such Executives’ employment agreements. In connection with the Executives agreeing to the Amendments, on July 24, 2019, the Company issued each of Dr. Gullans, Dr. Bisgaier and Mr. Reno a restricted stock award representing 300,000, 100,000 and 100,000 shares, respectively, of common stock. The restricted stock awards were made pursuant to Restricted Stock Grant Notices and Restricted Stock Agreements (the “Award Agreements”). Such Award Agreements provide that such shares shall fully vest immediately prior to the Effective Time, provided that the Executive has executed and delivered to the Company a release and waiver of claims and such release is not subsequently revoked. The Company shall automatically reacquire for no consideration all unvested shares upon the earliest to occur of (i) the Executive’s termination of continuous service (unless such termination results from the completion of the Merger prior to March 31, 2020) or (ii) March 31, 2020 if the Merger has not been completed. The Award Agreements provide that the holders shall have all rights and privileges of a holder of common stock, including for purposes of voting and receiving dividends. Grants were also made to the Company’s non-employee directors (45,000 shares of restricted stock in the aggregate) and employees (62,000 shares of restricted stock in the aggregate) pursuant to Award Agreements on July 24, 2019. The non-employee director Award Agreements do not require the execution and delivery of a release and waiver of claims. On July 23, 2019, the Company’s non-employee directors agreed to waive payment of the cash retainer for the remainder of 2019 otherwise payable to such directors pursuant to the Company’s non-employee director compensation policy.

3. Merger Agreement

Merger Agreement with NeuroBo

On July 24, 2019, the Company entered into the Merger Agreement with NeuroBo pursuant to which, the Company’s wholly owned subsidiary, Merger Sub, will merge with and into NeuroBo, with NeuroBo surviving as a wholly owned subsidiary of the Company, in an all-stock transaction. Subject to the terms and conditions of the Merger Agreement, at the effective time of the Merger (the “Effective Time”), (a) each share of NeuroBo common stock outstanding immediately prior to the Effective Time (excluding shares held as treasury stock, held by NeuroBo and dissenting shares) will be converted into the right to receive shares of Gemphire common stock equal to the Exchange Ratio described below; and (b) each outstanding NeuroBo stock option that has not previously been exercised prior to the Effective Time will be assumed by the Company.

For accounting purposes, NeuroBo is considered to be acquiring the Company even though the Company will be the issuer of the common stock in the merger due to various considerations, including the expected ownership positions of Gemphire and NeuroBo post-merger. Substantially all the fair value of the Company is concentrated in one asset, in-process research and development IP, and therefore the merger is expected to be accounted for as an asset acquisition by NeuroBo.

Under the exchange ratio formula in the Merger Agreement (the “Exchange Ratio”), upon the closing of the Merger, on a pro forma basis and based upon the number of shares of common stock expected to be issued in the Merger, former Company security holders immediately prior to the Merger are expected to own, or hold rights to acquire, approximately 3.74% of the combined company and former NeuroBo security holders immediately prior to the Merger are expected to own, or hold rights to acquire, approximately 96.26% of the combined company, on a fully-diluted basis and assuming that the Company has a net cash amount of negative $3,400,000 at closing and that NeuroBo raises the minimum required amount of $24,240,000 in its Series B Preferred Stock financing described below. The ownership percentages are subject to adjustment to the extent that the Company’s net cash at the Effective Time is negative or to reflect aggregate gross proceeds received by NeuroBo in its financing before the closing of the Merger above the minimum required amount and up to and including $50 million.

Consummation of the Merger is subject to certain closing conditions, including, among other things, approval by the Company’s stockholders and NeuroBo’s stockholders, the continued listing of the common stock on the Nasdaq Capital Market, the conversion of all NeuroBo preferred stock and NeuroBo convertible notes into NeuroBo common stock and satisfaction by the Company of a minimum parent cash amount of negative $3.75 million at closing.

Prior to signing the Merger Agreement, NeuroBo entered into subscription agreements with investors for a Series B Preferred Stock financing for approximate gross proceeds of $24,240,000, the minimum required amount under the Merger Agreement, and may enter into additional subscription agreements and receive additional proceeds between signing and closing of the Merger.

The Merger Agreement contains certain termination rights for both the Company and NeuroBo, and further provides that, upon termination of the Merger Agreement under specified circumstances, either party may be required to pay the other party a termination fee of $1,000,000, or in some circumstances reimburse the other party’s expenses up to a maximum of $500,000.

Following the closing of the Merger, it is expected that NeuroBo’s Chief Executive Officer, John L. Brooks III, will serve as Chief Executive Officer of the Company and the board of directors of the Company will be comprised of ten directors, consisting of nine directors designated by NeuroBo and Steven Gullans, the Company’s current President and Chief Executive Officer. In addition, upon completion of the merger, Gemphire will change its name to NeuroBo Pharmaceuticals, Inc., and plans to change its ticker symbol on the Nasdaq Capital Market to “NRBO”. The merged company will focus on the development of NeuroBo’s clinical-stage drug candidates for the treatment of neurodegenerative diseases.

The Merger is expected to close in the fourth quarter of 2019, subject to approval by the Company’s stockholders at an annual meeting to be held on December 6, 2019 and other closing conditions.

Contingent Value Rights Agreement

At the Effective Time, the Company will enter into a Contingent Value Rights Agreement (the “CVR Agreement”). Pursuant to the Merger Agreement and the CVR Agreement, for each share of the Company’s common stock held, stockholders of record as of immediately prior to the Effective Time will receive one contingent value right (“CVR”) entitling such holders to receive in the aggregate, 80% of the Gross Consideration (as defined in the CVR Agreement which contemplates the post-Merger combined company’s prior retention of an aggregate of $500,000) less other Permitted Deductions (each as defined in the CVR Agreement) received during the 15-year period after the closing of the Merger (the “CVR Term”) from the grant, sale or transfer of rights to the Company’s product candidate gemcabene (other than a grant, sale or transfer of rights involving a sale or disposition of the post-Merger combined company) that is entered into during the 10-year period after the closing of the Merger or pursuant to the Beijing SL Agreement, but not including the $2.5 million non-refundable upfront gross payment pursuant to the Beijing SL Agreement, which was paid in October 2019. Under the CVR Agreement, the combined company agreed to commit $1 million to support the further development of gemcabene through the quarter ending March 31, 2020, the funding of which was conditioned on receipt by the Company of the $2.5 million non-refundable upfront gross payment payable under the Beijing SL Agreement. The CVRs are not transferable, except in certain limited circumstances, will not be certificated or evidenced by any instrument, will not accrue interest and will not be registered with the SEC or listed for trading on any exchange. The CVR Agreement will be effective prior to the closing of the Merger and will continue in effect until the later of the end of the CVR Term and the payment of all amounts payable thereunder, unless and until earlier terminated upon termination of the Merger Agreement.

Change in Control Payments and Severance Awards

On July 24, 2019, the Company entered into amendments to the employment agreements (the “Amendments”) of Dr. Steven Gullans, Chief Executive Officer and President, Dr. Charles Bisgaier, Chief Scientific Officer and Chairman of the board of directors, and Seth Reno, Chief Commercial Officer (the “Executives”) to reduce the cash severance obligation owed to each Executive in connection with the termination of their employment upon the closing of the Merger. Pursuant to the Amendments, if the Merger is completed, each of Dr. Gullans, Dr. Bisgaier and Mr. Reno will receive a lump sum cash payment within thirty days after the effective date of the Merger in an amount equal to $75,000, $330,000 and $297,536, respectively, subject to a reduction for withholding tax, in lieu of the cash compensation such Executives would otherwise be entitled to receive in connection with a termination following a change in control pursuant to such Executives’ employment agreements.

In connection with the Executives agreeing to the Amendments, on July 24, 2019, the Company issued each of Dr. Gullans, Dr. Bisgaier and Mr. Reno a restricted stock award representing 300,000, 100,000 and 100,000 shares, respectively, of common stock. The restricted stock awards were made pursuant to Restricted Stock Grant Notices and Restricted Stock Agreements (the “Award Agreements”). Such Award Agreements provide that such shares shall fully vest immediately prior to the Effective Time, provided that the Executive has executed and delivered to the Company a release and waiver of claims and such release is not subsequently revoked. The Company shall automatically reacquire for no consideration all unvested shares upon the earliest to occur of (i) the Executive’s termination of continuous service (unless such termination results from the completion of the Merger prior to March 31, 2020) or (ii) March 31, 2020 if the Merger has not been completed. The Award Agreements provide that the holders shall have all rights and privileges of a holder of common stock, including for purposes of voting and receiving dividends.

Grants were also made to the Company’s non-employee directors (45,000 shares of restricted stock in the aggregate) and employees (62,000 shares of restricted stock in the aggregate) pursuant to Award Agreements on July 24, 2019. The non-employee director Award Agreements do not require the execution and delivery of a release and waiver of claims.

On July 23, 2019, the Company’s non-employee directors agreed to waive payment of the cash retainer for the remainder of 2019 otherwise payable to such directors pursuant to the Company’s non-employee director compensation policy.