Significant Accounting Policies (Policies)	3 Months Ended
Mar. 31, 2023
Accounting Policies [Abstract]
Business Description of Entity [Policy Text Block]	*The Company* AcelRx Pharmaceuticals, Inc., or the Company, or AcelRx, was incorporated in Delaware on July 13, 2005 as SuRx, Inc. The Company subsequently changed its name to AcelRx Pharmaceuticals, Inc. The Company’s operations are based in Hayward, California. AcelRx is a specialty pharmaceutical company focused on the development and commercialization of innovative therapies for use in medically supervised settings. On March 12, 2023, the Company entered into an Asset Purchase Agreement, or the Purchase Agreement, with Vertical Pharmaceuticals, LLC, a wholly owned subsidiary of Alora Pharmaceuticals, LLC, or Alora, pursuant to which Alora agreed to acquire certain assets and assume certain liabilities of AcelRx relating to its sufentanil sublingual tablet product referred to as DSUVIA or DZUVEO, or any other single-dose pharmaceutical product for use in medically supervised settings containing a sublingual tablet that includes sufentanil as the sole active ingredient, as a 30 mcg tablet or other dosage form or strength as reasonably necessary for lifecycle management, or the Product. The closing of the Purchase Agreement occurred on April 3, 2023 (see Note 3, “Discontinued Operations” and Note 11, “Subsequent Events” below). On January 7, 2022, the Company acquired Lowell Therapeutics, Inc., or Lowell, a privately held company (see Note 4, “Asset Acquisition” below), and, as a result acquired Niyad™, a regional anticoagulant for the dialysis circuit during continuous renal replacement therapy for acute kidney injury patients in the hospital, that the Company plans to study under an investigational device exemption, or IDE, and which has received Breakthrough Device Designation status from the FDA. While not approved for commercial use in the United States, the active drug component of Niyad, nafamostat, has been approved in Japan and South Korea as a regional anticoagulant for the dialysis circuit, disseminated intravascular coagulation, and acute pancreatitis. Niyad is a lyophilized formulation of nafamostat, a broad-spectrum, synthetic serine protease inhibitor, with anticoagulant, anti-inflammatory, and potential anti-viral activities. The second intended indication for Niyad is as a regional anticoagulant for the dialysis circuit for chronic kidney disease patients undergoing intermittent hemodialysis in dialysis centers. In addition, the Company acquired LTX-608, a proprietary nafamostat formulation for direct IV infusion that it intends to develop for the treatment of acute respiratory distress syndrome, or ARDS, and disseminated intravascular coagulation, or DIC. On July 14, 2021, the Company entered into a License and Commercialization Agreement, or the PFS Agreement, with Laboratoire Aguettant, or Aguettant, pursuant to which the Company obtained the exclusive right to develop and, subject to FDA approval, commercialize in the United States an ephedrine pre-filled syringe, or PFS, containing 10 ml of a solution of 3 mg/ml ephedrine hydrochloride for injection, and (ii) a phenylephrine PFS containing 10 ml of a solution of 50 mcg/ml phenylephrine for injection. Aguettant will supply the Company with the products for use in commercialization and, if they are approved in the U.S. *Liquidity and Going Concern* The unaudited condensed consolidated financial statements for the three months ended March 31, 2023 were prepared on the basis of a going concern, which contemplates that the Company will be able to realize assets and discharge liabilities in the normal course of business. The Company has incurred recurring operating losses and negative cash flows from operating activities and expects to continue to incur operating losses and negative cash flows in the future. These conditions raise substantial doubt about the Company’s ability to continue as a going concern. Considering the Company’s current cash resources and its current and expected levels of operating expenses for the next twelve months, management expects to need additional capital to fund its planned operations prior to the 12 month anniversary of the date this Quarterly Report on Form 10-Q is filed with the United States Securities and Exchange Commission, or the SEC. Management may seek to raise such additional capital through public or private equity offerings, including under the Controlled Equity Offering^SM Sales Agreement, or the ATM Agreement, with Cantor Fitzgerald & Co., or Cantor, debt securities, a new debt facility, monetizing or securitizing certain assets, entering into product development, license or distribution agreements with third parties, or divesting any of the Company’s remaining product candidates. While management believes its plans to raise additional funds will alleviate the conditions that raise substantial doubt about the Company’s ability to continue as a going concern, these plans are not entirely within the Company’s control and cannot be assessed as being probable of occurring. Additional funds may not be available when the Company needs them on terms that are acceptable to the Company, or at all. If adequate funds are not available, the Company may be required to further reduce its workforce or delay the development of its regulatory filing plans for its product candidates in advance of the date on which the Company’s cash resources are exhausted to ensure that the Company has sufficient capital to meet its obligations and continue on a path designed to preserve stockholder value. In addition, if additional funds are raised through collaborations, strategic alliances or licensing arrangements with third parties, the Company may have to relinquish rights to its technologies, future revenue streams or product candidates, or to grant licenses on terms that may not be favorable to the Company.
Reverse Stock Split, Policy [Policy Text Block]	*Reverse Stock Split* On September 23, 2022, at a special meeting of stockholders, the Company's stockholders authorized the Company’s Board of Directors to effect a reverse stock split of all outstanding shares of common stock in a range of 1-for-10 to 1-for-30. The Board of Directors subsequently approved a reverse stock split with a ratio of 1-for-20, or the Reverse Stock Split. On October 25, 2022, following the filing of a certificate of amendment to the Company’s amended and restated certificate of incorporation, every 20 shares of the Company's common stock that were issued and outstanding automatically converted into one outstanding share of common stock. The Reverse Stock Split affected all shares of common stock outstanding immediately prior to the effective time of the Reverse Stock Split, as well as the number of shares of common stock available for issuance under the Company's equity incentive and employee stock purchase plans. Outstanding stock options, restricted stock units and warrants were proportionately reduced and the respective exercise prices, if applicable, were proportionately increased. The Reverse Stock Split affected all holders of common stock uniformly and did not affect any stockholder's percentage of ownership interest. The par value of the Company's common stock remained unchanged at $0.001 per share and the number of authorized shares of common stock remained the same after the Reverse Stock Split. As the par value per share of the Company's common stock remained unchanged at $0.001 per share, the change in the common stock recorded at par value has been reclassified to additional paid-in-capital on a retroactive basis. All references to shares of common stock, stock options, restricted stock units and warrants and per share data for all periods presented in the accompanying unaudited condensed consolidated financial statements and notes thereto have been adjusted to reflect the Reverse Stock Split on a retroactive basis.
Consolidation, Policy [Policy Text Block]	*Principles of Consolidation* The unaudited condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation.
Basis of Accounting, Policy [Policy Text Block]	*Basis of Presentation* The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States for interim financial information and the rules and regulations of the United States. Securities and Exchange Commission, or SEC. Accordingly, they do not include all of the information and footnotes required by accounting principles generally accepted in the United States for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring adjustments) considered necessary for a fair presentation have been included. Operating results for the three months ended March 31, 2023, are not necessarily indicative of the results that may be expected for the year ending December 31, 2023, or any future period. The condensed consolidated balance sheet as of December 31, 2022, was derived from the Company’s audited financial statements as of December 31, 2022, included in the Company’s Annual Report on Form 10-K filed with the SEC on March 31, 2023. These financial statements should be read in conjunction with the Company’s Annual Report on Form 10-K for the year ended December 31, 2022, which includes a broader discussion of the Company’s business and the risks inherent therein.
Use of Estimates, Policy [Policy Text Block]	*Use of Estimates* The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the amounts reported in the Consolidated Financial Statements and accompanying notes. Management evaluates its estimates on an ongoing basis including critical accounting policies. Estimates are based on historical experience and on various other market-specific and other relevant assumptions that the Company believes to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results could differ from those estimates.
New Accounting Pronouncements, Policy [Policy Text Block]	*Recently Adopted Accounting Pronouncements* In June 2016, the Financial Accounting Standards Board, or FASB, issued Topic 326, or the Credit Losses standard, which the Company adopted using a modified retrospective approach on January 1, 2023. Topic 326 requires that expected credit losses relating to financial assets measured on an amortized cost basis and available-for-sale debt securities be recorded through an allowance for credit losses. It also limits the amount of credit losses to be recognized for available-for-sale debt securities to the amount by which carrying value exceeds fair value. The adoption of this standard did not have a material impact on the Company’s financial statements or related disclosures. The Company does not believe other recently issued but not yet effective accounting standards, if currently adopted, would have a material effect on the consolidated financial position, statements of operations and cash flows. *Significant Accounting Policies* The Company’s significant accounting policies are detailed in its Annual Report on Form 10-K for the year ended December 31, 2022. There have been no significant changes to the Company’s significant accounting policies during the three months ended March 31, 2023, from those previously disclosed in its 2022 Annual Report on Form 10-K, except as follows: In accordance with ASC 205-20 “Presentation of Financial Statements: Discontinued Operations”, a disposal of a component of an entity or a group of components of an entity is required to be reported as discontinued operations if the disposal represents a strategic shift that has (or will have) a major effect on an entity’s operations and financial results. In the period in which the component meets held-for-sale or discontinued operations criteria the major current assets, non-current assets, current liabilities, and non-current liabilities shall be reported as components of total assets and liabilities separate from those balances of the continuing operations. At the same time, the results of all discontinued operations, less applicable income taxes, shall be reported as components of net loss separate from the net income (loss) of continuing operations. The Company’s DSUVIA business met the definition of a discontinued operation as of March 31, 2023. Accordingly, the Company has classified the results of the DSUVIA business as discontinued operations in its unaudited condensed consolidated statements of operations for all periods presented. All assets and liabilities associated with the DSUVIA business were classified as assets and liabilities of discontinued operations in the unaudited condensed consolidated balance sheets for the periods presented. All amounts included in the notes to the unaudited condensed consolidated financial statements relate to continuing operations unless otherwise noted. For additional information, see Note 3, “Discontinued Operations”.

Significant Accounting Policies (Policies)

3 Months Ended

Mar. 31, 2023

Business Description of Entity [Policy Text Block]

The Company

AcelRx Pharmaceuticals, Inc., or the Company, or AcelRx, was incorporated in Delaware on July 13, 2005 as SuRx, Inc. The Company subsequently changed its name to AcelRx Pharmaceuticals, Inc. The Company’s operations are based in Hayward, California.

AcelRx is a specialty pharmaceutical company focused on the development and commercialization of innovative therapies for use in medically supervised settings.

On March 12, 2023, the Company entered into an Asset Purchase Agreement, or the Purchase Agreement, with Vertical Pharmaceuticals, LLC, a wholly owned subsidiary of Alora Pharmaceuticals, LLC, or Alora, pursuant to which Alora agreed to acquire certain assets and assume certain liabilities of AcelRx relating to its sufentanil sublingual tablet product referred to as DSUVIA or DZUVEO, or any other single-dose pharmaceutical product for use in medically supervised settings containing a sublingual tablet that includes sufentanil as the sole active ingredient, as a 30 mcg tablet or other dosage form or strength as reasonably necessary for lifecycle management, or the Product. The closing of the Purchase Agreement occurred on April 3, 2023 (see Note 3, “Discontinued Operations” and Note 11, “Subsequent Events” below).

On January 7, 2022, the Company acquired Lowell Therapeutics, Inc., or Lowell, a privately held company (see Note 4, “Asset Acquisition” below), and, as a result acquired Niyad™, a regional anticoagulant for the dialysis circuit during continuous renal replacement therapy for acute kidney injury patients in the hospital, that the Company plans to study under an investigational device exemption, or IDE, and which has received Breakthrough Device Designation status from the FDA. While not approved for commercial use in the United States, the active drug component of Niyad, nafamostat, has been approved in Japan and South Korea as a regional anticoagulant for the dialysis circuit, disseminated intravascular coagulation, and acute pancreatitis. Niyad is a lyophilized formulation of nafamostat, a broad-spectrum, synthetic serine protease inhibitor, with anticoagulant, anti-inflammatory, and potential anti-viral activities. The second intended indication for Niyad is as a regional anticoagulant for the dialysis circuit for chronic kidney disease patients undergoing intermittent hemodialysis in dialysis centers. In addition, the Company acquired LTX-608, a proprietary nafamostat formulation for direct IV infusion that it intends to develop for the treatment of acute respiratory distress syndrome, or ARDS, and disseminated intravascular coagulation, or DIC.

On July 14, 2021, the Company entered into a License and Commercialization Agreement, or the PFS Agreement, with Laboratoire Aguettant, or Aguettant, pursuant to which the Company obtained the exclusive right to develop and, subject to FDA approval, commercialize in the United States an ephedrine pre-filled syringe, or PFS, containing 10 ml of a solution of 3 mg/ml ephedrine hydrochloride for injection, and (ii) a phenylephrine PFS containing 10 ml of a solution of 50 mcg/ml phenylephrine for injection. Aguettant will supply the Company with the products for use in commercialization and, if they are approved in the U.S.

Liquidity and Going Concern

The unaudited condensed consolidated financial statements for the three months ended March 31, 2023 were prepared on the basis of a going concern, which contemplates that the Company will be able to realize assets and discharge liabilities in the normal course of business. The Company has incurred recurring operating losses and negative cash flows from operating activities and expects to continue to incur operating losses and negative cash flows in the future. These conditions raise substantial doubt about the Company’s ability to continue as a going concern. Considering the Company’s current cash resources and its current and expected levels of operating expenses for the next twelve months, management expects to need additional capital to fund its planned operations prior to the 12 month anniversary of the date this Quarterly Report on Form 10-Q is filed with the United States Securities and Exchange Commission, or the SEC. Management may seek to raise such additional capital through public or private equity offerings, including under the Controlled Equity Offering^SM Sales Agreement, or the ATM Agreement, with Cantor Fitzgerald & Co., or Cantor, debt securities, a new debt facility, monetizing or securitizing certain assets, entering into product development, license or distribution agreements with third parties, or divesting any of the Company’s remaining product candidates. While management believes its plans to raise additional funds will alleviate the conditions that raise substantial doubt about the Company’s ability to continue as a going concern, these plans are not entirely within the Company’s control and cannot be assessed as being probable of occurring. Additional funds may not be available when the Company needs them on terms that are acceptable to the Company, or at all. If adequate funds are not available, the Company may be required to further reduce its workforce or delay the development of its regulatory filing plans for its product candidates in advance of the date on which the Company’s cash resources are exhausted to ensure that the Company has sufficient capital to meet its obligations and continue on a path designed to preserve stockholder value. In addition, if additional funds are raised through collaborations, strategic alliances or licensing arrangements with third parties, the Company may have to relinquish rights to its technologies, future revenue streams or product candidates, or to grant licenses on terms that may not be favorable to the Company.

Reverse Stock Split, Policy [Policy Text Block]

Reverse Stock Split

On September 23, 2022, at a special meeting of stockholders, the Company's stockholders authorized the Company’s Board of Directors to effect a reverse stock split of all outstanding shares of common stock in a range of 1-for-10 to 1-for-30. The Board of Directors subsequently approved a reverse stock split with a ratio of 1-for-20, or the Reverse Stock Split. On October 25, 2022, following the filing of a certificate of amendment to the Company’s amended and restated certificate of incorporation, every 20 shares of the Company's common stock that were issued and outstanding automatically converted into one outstanding share of common stock. The Reverse Stock Split affected all shares of common stock outstanding immediately prior to the effective time of the Reverse Stock Split, as well as the number of shares of common stock available for issuance under the Company's equity incentive and employee stock purchase plans. Outstanding stock options, restricted stock units and warrants were proportionately reduced and the respective exercise prices, if applicable, were proportionately increased. The Reverse Stock Split affected all holders of common stock uniformly and did not affect any stockholder's percentage of ownership interest. The par value of the Company's common stock remained unchanged at $0.001 per share and the number of authorized shares of common stock remained the same after the Reverse Stock Split.

As the par value per share of the Company's common stock remained unchanged at $0.001 per share, the change in the common stock recorded at par value has been reclassified to additional paid-in-capital on a retroactive basis. All references to shares of common stock, stock options, restricted stock units and warrants and per share data for all periods presented in the accompanying unaudited condensed consolidated financial statements and notes thereto have been adjusted to reflect the Reverse Stock Split on a retroactive basis.

Consolidation, Policy [Policy Text Block]

Principles of Consolidation

The unaudited condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation.

Basis of Accounting, Policy [Policy Text Block]

Basis of Presentation

The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States for interim financial information and the rules and regulations of the United States. Securities and Exchange Commission, or SEC. Accordingly, they do not include all of the information and footnotes required by accounting principles generally accepted in the United States for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring adjustments) considered necessary for a fair presentation have been included.

Operating results for the three months ended March 31, 2023, are not necessarily indicative of the results that may be expected for the year ending December 31, 2023, or any future period. The condensed consolidated balance sheet as of December 31, 2022, was derived from the Company’s audited financial statements as of December 31, 2022, included in the Company’s Annual Report on Form 10-K filed with the SEC on March 31, 2023. These financial statements should be read in conjunction with the Company’s Annual Report on Form 10-K for the year ended December 31, 2022, which includes a broader discussion of the Company’s business and the risks inherent therein.

Use of Estimates, Policy [Policy Text Block]

Use of Estimates

The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the amounts reported in the Consolidated Financial Statements and accompanying notes. Management evaluates its estimates on an ongoing basis including critical accounting policies. Estimates are based on historical experience and on various other market-specific and other relevant assumptions that the Company believes to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results could differ from those estimates.

New Accounting Pronouncements, Policy [Policy Text Block]

Recently Adopted Accounting Pronouncements

In June 2016, the Financial Accounting Standards Board, or FASB, issued Topic 326, or the Credit Losses standard, which the Company adopted using a modified retrospective approach on January 1, 2023. Topic 326 requires that expected credit losses relating to financial assets measured on an amortized cost basis and available-for-sale debt securities be recorded through an allowance for credit losses. It also limits the amount of credit losses to be recognized for available-for-sale debt securities to the amount by which carrying value exceeds fair value. The adoption of this standard did not have a material impact on the Company’s financial statements or related disclosures.

The Company does not believe other recently issued but not yet effective accounting standards, if currently adopted, would have a material effect on the consolidated financial position, statements of operations and cash flows.

Significant Accounting Policies

The Company’s significant accounting policies are detailed in its Annual Report on Form 10-K for the year ended December 31, 2022. There have been no significant changes to the Company’s significant accounting policies during the three months ended March 31, 2023, from those previously disclosed in its 2022 Annual Report on Form 10-K, except as follows:

In accordance with ASC 205-20 “Presentation of Financial Statements: Discontinued Operations”, a disposal of a component of an entity or a group of components of an entity is required to be reported as discontinued operations if the disposal represents a strategic shift that has (or will have) a major effect on an entity’s operations and financial results. In the period in which the component meets held-for-sale or discontinued operations criteria the major current assets, non-current assets, current liabilities, and non-current liabilities shall be reported as components of total assets and liabilities separate from those balances of the continuing operations. At the same time, the results of all discontinued operations, less applicable income taxes, shall be reported as components of net loss separate from the net income (loss) of continuing operations.

The Company’s DSUVIA business met the definition of a discontinued operation as of March 31, 2023. Accordingly, the Company has classified the results of the DSUVIA business as discontinued operations in its unaudited condensed consolidated statements of operations for all periods presented. All assets and liabilities associated with the DSUVIA business were classified as assets and liabilities of discontinued operations in the unaudited condensed consolidated balance sheets for the periods presented. All amounts included in the notes to the unaudited condensed consolidated financial statements relate to continuing operations unless otherwise noted. For additional information, see Note 3, “Discontinued Operations”.