BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies) - Q1	3 Months Ended
Mar. 31, 2024
Accounting Policies [Abstract]
Basis of Accounting	References in this Annual Report to “authoritative guidance” is meant to refer to accounting principles generally accepted in the United States of America (GAAP) as found in the Accounting Standards Codification (ASC) and Accounting Standards Updates (ASU) of the Financial Accounting Standards Board (FASB). The accompanying unaudited interim financial statements have been prepared in accordance with accounting principles generally accepted in the United States (GAAP) for interim financial periods and pursuant to the rules of the Securities and Exchange Commission (the SEC). Any reference in the accompanying unaudited interim financial statements to “authoritative guidance” is meant to refer to GAAP as found in the Accounting Standards Codification (ASC) and Accounting Standards Updates (ASU) of the Financial Accounting Standards Board (FASB). The December 31, 2023 balance sheet was derived from the Company’s audited consolidated financial statements.
Principles of Consolidation	Principles of Consolidation The consolidated financial statements include the accounts of GRI Bio, Inc. and its wholly-owned subsidiary, GRI Bio Operations, Inc. All intercompany balances and transactions have been eliminated. Principles of Consolidation The unaudited interim consolidated financial statements include the accounts of GRI Bio, Inc. and its wholly-owned subsidiary, GRI Bio Operations, Inc. All intercompany balances and transactions have been eliminated.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Estimates and assumptions are primarily made in relation to the valuation of share options, the embedded derivative of convertible notes, warrant issuance and subsequent revaluations, valuation allowances relating to deferred tax assets, revenue recognition, accrued expenses and estimation of the incremental borrowing rate for the finance lease. If actual results differ from the Company’s estimates, or to the extent these estimates are adjusted in future periods, the Company’s results of operations could either benefit from, or be adversely affected by, any such change in estimate. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Estimates and assumptions are primarily made in relation to the valuation of share options, warrant issuance and subsequent revaluations, valuation allowances relating to deferred tax assets, accrued expenses and estimation of the incremental borrowing rate for the operating lease. If actual results differ from the Company’s estimates, or to the extent these estimates are adjusted in future periods, the Company’s consolidated results of operations could either benefit from, or be adversely affected by, any such change in estimate.
Fair Value Measurements	Fair Value Measurements Fair value is defined as the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. To increase consistency and comparability in fair value measurements and related disclosures, ASC 820, Fair Value Measurement, (ASC 820) establishes a fair value hierarchy which prioritizes the inputs to valuation techniques used to measure fair value into three broad levels. The three levels of fair value hierarchy defined by ASC 820 are described below: Level 1:Quoted market prices available in active markets for identical assets or liabilities as of the reporting date. Level 2:Pricing inputs other than quoted prices in active markets included in Level 1, which are either directly or indirectly observable as of the reporting date. Level 3:Pricing inputs that are generally unobservable inputs and not corroborated by market data. As of March 31, 2024, the Company’s financial instruments included cash, cash equivalents, prepaid expenses and other current assets, accounts payable, accrued expenses and certain liability classified warrants. The carrying amounts reported in the balance sheets for cash, prepaid expenses and other current assets, accounts payable and accrued expenses approximate their fair value based on the short-term maturity of these instruments. The Company recognizes transfers between levels of the fair value hierarchy on the date of the event or change in circumstances that caused the transfer. At March 31, 2024, there were no financial assets or liabilities measured at fair value on a recurring basis other than the liability classified warrants. In May 2022, Vallon Pharmaceuticals, Inc. (Vallon) issued warrants in connection with a securities purchase agreement. Vallon evaluated the warrants in accordance with ASC 815-40, Derivatives and Hedging — Contracts in Entity’s Own Equity (ASC 815-40), and concluded that a provision in the warrants related to the reduction of the exercise price in certain circumstances precluded the warrants from being accounted for as components of equity. As a result, the warrants were recorded as a liability on the balance sheet. Vallon recorded the fair value of the warrants upon issuance using a Black-Scholes valuation model. The Company is required to revalue the warrants at each reporting date with any changes in fair value recorded in its statement of operations. The valuation of the warrants is considered under Level 3 of the fair value hierarchy due to the need to use assumptions in the valuation that are both significant to the fair value measurement and unobservable. The change in the fair value of the Level 3 warrants liabilities is reflected in the statement of operations for the three months ended March 31, 2024.
Net Loss Per Common Share	Net Loss Per Common Share Basic net loss per common share is computed based on the weighted average number of shares of common stock outstanding during each year. Diluted net loss per common share is computed based on the weighted average number of shares of common stock outstanding during each year, plus the dilutive effect of options considered to be outstanding during each year, in accordance with ASC 260, Earnings Per Share. As the Company had a net loss in each of the years ended December 31, 2023 and 2022, diluted net loss per common share is the same as basic net loss per common share for the period because the effects of potentially dilutive securities are antidilutive. Net Loss Per Common Share Basic and diluted net loss per common share is computed based on the weighted average number of shares of common stock outstanding during each year. Diluted net loss per common share is computed based on the weighted average number of shares of common stock outstanding during each year, plus the dilutive effect of options considered to be outstanding during each year, in accordance with ASC 260, Earnings Per Share. As the Company had a net loss in each of the three months ended March 31, 2024 and 2023, diluted net loss per common share is the same as basic net loss per common share for the period because the effects of potentially dilutive securities are antidilutive.
Recent Accounting Pronouncements	Recent Accounting Pronouncements The Company considers the applicability and impact of all ASUs. ASUs not discussed below were assessed and determined to be either not applicable or are expected to have minimal impact on the financial statements. In December 2023, FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures (ASU 2023-09). The amendments in ASU 2023-09 are intended to enhance the transparency and decision usefulness of income tax disclosures through improvements to income tax disclosures primarily related to the rate reconciliation and income taxes paid information. ASU 2023-09 is effective for annual periods beginning after December 15, 2024 for public entities, with early adoption permitted. Management is currently evaluating the impact of this update on the Company’s financial statements. In October 2023, FASB issued ASU 2023-06, Disclosure Improvements: Codification Amendments in Response to the SEC’s Disclosure Update and Simplification Initiative (ASU 2023-06). The amendments in ASU 2023-06 represent changes to clarify or improve disclosure and presentation requirements of a variety of topics in the Codification and align those requirements with the SEC’s regulation. For entities subject to the Security and Exchange Commission’s (SEC) existing disclosure requirements, the effective date for each amendment will be the date on which the SEC’s removal of that related disclosure from Regulation S-X or Regulation S-K becomes effective, with early adoption prohibited. Management is currently evaluating the impact of this update and its effective dates but does not expect the update to have a material effect on the Company’s financial statements. On January 1, 2022, the Company adopted ASU 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40) (ASU 2020-06). ASU 2020-06 address issues identified as a result of the complexity associated with applying GAAP for certain financial instruments with characteristics of liabilities and equity.The amendments focused on amending the guidance on convertible instruments and the guidance on the derivatives scope exception for contracts in an entity’s own equity. The adoption of this standard did not have a material impact on the Company’s financial statements. Recent Accounting Pronouncements The Company considered the applicability and impact of all ASUs issued during the quarter ended March 31, 2024 and each was determined to be either not applicable or expected to have minimal impact on these consolidated financial statements.

BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies) - Q1

3 Months Ended

Mar. 31, 2024

References in this Annual Report to “authoritative guidance” is meant to refer to accounting principles generally accepted in the United States of America (GAAP) as found in the Accounting Standards Codification (ASC) and Accounting Standards Updates (ASU) of the Financial Accounting Standards Board (FASB).

The accompanying unaudited interim financial statements have been prepared in accordance with accounting principles generally accepted in the United States (GAAP) for interim financial periods and pursuant to the rules of the Securities and Exchange Commission (the SEC). Any reference in the accompanying unaudited interim financial statements to “authoritative guidance” is meant to refer to GAAP as found in the Accounting Standards Codification (ASC) and Accounting Standards Updates (ASU) of the Financial Accounting Standards Board (FASB). The December 31, 2023 balance sheet was derived from the Company’s audited consolidated financial statements.

Principles of Consolidation

The consolidated financial statements include the accounts of GRI Bio, Inc. and its wholly-owned subsidiary, GRI Bio Operations, Inc. All intercompany balances and transactions have been eliminated.

Principles of Consolidation

The unaudited interim consolidated financial statements include the accounts of GRI Bio, Inc. and its wholly-owned subsidiary, GRI Bio Operations, Inc. All intercompany balances and transactions have been eliminated.

Use of Estimates

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Estimates and assumptions are primarily made in relation to the valuation of share options, the embedded derivative of convertible notes, warrant issuance and subsequent revaluations, valuation allowances relating to deferred tax assets, revenue recognition, accrued expenses and estimation of the incremental borrowing rate for the finance lease. If actual results differ from the Company’s estimates, or to the extent these estimates are adjusted in future periods, the Company’s results of operations could either benefit from, or be adversely affected by, any such change in estimate.

Use of Estimates

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Estimates and assumptions are primarily made in relation to the valuation of share options, warrant issuance and subsequent revaluations, valuation allowances relating to deferred tax assets, accrued expenses and estimation of the incremental borrowing rate for the operating lease. If actual results differ from the Company’s estimates, or to the extent these estimates are adjusted in future periods, the Company’s consolidated results of operations could either benefit from, or be adversely affected by, any such change in estimate.

Fair Value Measurements

Fair value is defined as the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. To increase consistency and comparability in fair value measurements and related disclosures, ASC 820, Fair Value Measurement, (ASC 820) establishes a fair value hierarchy which prioritizes the inputs to valuation techniques used to measure fair value into three broad levels. The three levels of fair value hierarchy defined by ASC 820 are described below:

Level 1:Quoted market prices available in active markets for identical assets or liabilities as of the reporting date.

Level 2:Pricing inputs other than quoted prices in active markets included in Level 1, which are either directly or indirectly observable as of the reporting date.

Level 3:Pricing inputs that are generally unobservable inputs and not corroborated by market data.

As of March 31, 2024, the Company’s financial instruments included cash, cash equivalents, prepaid expenses and other current assets, accounts payable, accrued expenses and certain liability classified warrants. The carrying amounts reported in the balance sheets for cash, prepaid expenses and other current assets, accounts payable and accrued expenses approximate their fair value based on the short-term maturity of these instruments. The Company

recognizes transfers between levels of the fair value hierarchy on the date of the event or change in circumstances that caused the transfer. At March 31, 2024, there were no financial assets or liabilities measured at fair value on a recurring basis other than the liability classified warrants.

In May 2022, Vallon Pharmaceuticals, Inc. (Vallon) issued warrants in connection with a securities purchase agreement. Vallon evaluated the warrants in accordance with ASC 815-40, Derivatives and Hedging — Contracts in Entity’s Own Equity (ASC 815-40), and concluded that a provision in the warrants related to the reduction of the exercise price in certain circumstances precluded the warrants from being accounted for as components of equity. As a result, the warrants were recorded as a liability on the balance sheet. Vallon recorded the fair value of the warrants upon issuance using a Black-Scholes valuation model.

The Company is required to revalue the warrants at each reporting date with any changes in fair value recorded in its statement of operations. The valuation of the warrants is considered under Level 3 of the fair value hierarchy due to the need to use assumptions in the valuation that are both significant to the fair value measurement and unobservable. The change in the fair value of the Level 3 warrants liabilities is reflected in the statement of operations for the three months ended March 31, 2024.

Net Loss Per Common Share

Basic net loss per common share is computed based on the weighted average number of shares of common stock outstanding during each year. Diluted net loss per common share is computed based on the weighted average number of shares of common stock outstanding during each year, plus the dilutive effect of options considered to be outstanding during each year, in accordance with ASC 260, Earnings Per Share. As the Company had a net loss in each of the years ended December 31, 2023 and 2022, diluted net loss per common share is the same as basic net loss per common share for the period because the effects of potentially dilutive securities are antidilutive.

Net Loss Per Common Share

Basic and diluted net loss per common share is computed based on the weighted average number of shares of common stock outstanding during each year. Diluted net loss per common share is computed based on the weighted average number of shares of common stock outstanding during each year, plus the dilutive effect of options considered to be outstanding during each year, in accordance with ASC 260, Earnings Per Share. As the Company had a net loss in each of the three months ended March 31, 2024 and 2023, diluted net loss per common share is the same as basic net loss per common share for the period because the effects of potentially dilutive securities are antidilutive.

Recent Accounting Pronouncements

The Company considers the applicability and impact of all ASUs. ASUs not discussed below were assessed and determined to be either not applicable or are expected to have minimal impact on the financial statements.

In December 2023, FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures (ASU 2023-09). The amendments in ASU 2023-09 are intended to enhance the transparency and decision usefulness of income tax disclosures through improvements to income tax disclosures primarily related to the rate reconciliation and income taxes paid information. ASU 2023-09 is effective for annual periods beginning after December 15, 2024 for public entities, with early adoption permitted. Management is currently evaluating the impact of this update on the Company’s financial statements.

In October 2023, FASB issued ASU 2023-06, Disclosure Improvements: Codification Amendments in Response to the SEC’s Disclosure Update and Simplification Initiative (ASU 2023-06). The amendments in ASU 2023-06 represent changes to clarify or improve disclosure and presentation requirements of a variety of topics in the Codification and align those requirements with the SEC’s regulation. For entities subject to the Security and Exchange Commission’s (SEC) existing disclosure requirements, the effective date for each amendment will be the date on which the SEC’s removal of that related disclosure from Regulation S-X or Regulation S-K becomes effective, with early adoption prohibited. Management is currently evaluating the impact of this update and its effective dates but does not expect the update to have a material effect on the Company’s financial statements.

On January 1, 2022, the Company adopted ASU 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40) (ASU 2020-06). ASU 2020-06 address issues identified as a result of the complexity associated with applying GAAP for certain financial instruments with characteristics of liabilities and equity.The amendments focused on amending the guidance on convertible instruments and the guidance on the derivatives scope exception for contracts in an entity’s own equity. The adoption of this standard did not have a material impact on the Company’s financial statements.

Recent Accounting Pronouncements

The Company considered the applicability and impact of all ASUs issued during the quarter ended March 31, 2024 and each was determined to be either not applicable or expected to have minimal impact on these consolidated financial statements.