Organization and Basis of Presentation	12 Months Ended
Dec. 31, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Organization and Basis of Presentation	1. Organization and Basis of Presentation Allena Pharmaceuticals, Inc. (the “Company”) is a clinical stage company focused on developing non-absorbed oral enzyme therapeutics to treat metabolic conditions including hyperoxaluria and hyperuricemia. The Company was incorporated under the laws of the State of Delaware on June 24, 2011. The Company’s headquarters are in Newton, Massachusetts. The Company is subject to risks common to companies in the biotechnology industry, including but not limited to, risks of failure of preclinical studies and clinical trials, the need to obtain marketing approval for any drug product candidate that it may identify and develop, the need to successfully commercialize and gain market acceptance of its product candidates, dependence on key personnel, protection of proprietary technology, compliance with government regulations, development by competitors of technological innovations, reliance on third party manufacturers, ability to transition from pilot-scale manufacturing to large-scale production of products and the need to obtain adequate additional financing to fund the development of its product candidates. Liquidity and Going Concern The Company had an accumulated deficit of $246.5 million at December 31, 2021 and will require substantial additional capital to fund operations. The future success of the Company is dependent on its ability to identify and develop its product candidates and ultimately upon its ability to attain profitable operations. At December 31, 2021, the Company had $30.0 million of cash and cash equivalents. The Company’s available cash and cash equivalents as of December 31, 2021 are not sufficient to fund the Company’s current operating plan for at least the next twelve months following the filing of this Annual Report. The Company requires additional capital to sustain its operations, including its ALLN-346 development program. Management is exploring opportunities to secure additional funding through equity or debt financings or through collaborations, licensing transactions or other sources. In January 2022, the Company initiated a process to explore a range of strategic and financing alternatives to maximize shareholder value and has engaged the investment bank Stifel, Nicolaus & Company, Inc. ("Stifel") to act as strategic advisor for this process. Potential strategic alternatives that may be evaluated include a partnership or sale of ALLN-346, a sale or merger of the Company, or securing additional financing to enable further development of the Company's ALLN-346 program. There can be no assurance that this strategic review process will result in the Company pursuing any transaction or that any transaction, if pursued, will be completed. If the Company is unable to complete a transaction, it may be required to initiate a bankruptcy process. As part of the strategic process, the Compensation Committee of the Board of Directors approved a retention plan on January 28, 2022, available to all employees ("Retention Plan"). Employees were required to execute retention agreements to receive payments and other considerations offered by the Retention Plan. Employees who executed a retention agreement received a salary adjustment equal to 6.5% retroactive to January 1, 2022, a restricted stock unit ("RSU") grant and a lump sum retention payment. A total of 3,163,000 RSUs were granted on February 1, 2022 under the Retention Plan. The RSUs vest over a three-year period ratably on July 15th and January 15th of each year following grant date. Lump sum retention payments totaling $3.0 million were made to employees in February 2022. If an employee resigns from the Company or is terminated for cause prior to June 30, 2022, the employee would be required to fully repay the lump sum retention payment received. If an employee resigns from the Company or is terminated for cause between July 1, 2022 and September 30, 2022, the employee would be required to repay 50% of the lump sum retention payment received. During the first quarter of 2022, the Company made principal prepayments of $5.0 million of the $10.0 million that was outstanding as of December 31, 2021 under the loan and security agreement with Pontifax Medison Finance (Israel) L.P. and Pontifax Medison Finance (Cayman) L.P. (together “Pontifax”) (“Pontifax Agreement”). The outstanding principal balance as of the filing date of this Annual Report is $5.0 million. The Company also purchased Directors' & Officers' run-off insurance for $6.8 million in March 2022 to provide continued insurance coverage through any bankruptcy process with run off period of six years, which equal to the statute of limitations. On March 18, 2022, the Company announced that it was terminating its URIROX-2 study and reloxaliase program and initiated the process of closing the URIROX-2 study with the CRO, investigative sites, patients and business partners. In connection with the termination of the reloxaliase program, the Company completed a workforce reduction of approximately 40% on March 31, 2022. In accordance with the terms of the Retention Plan, the employees terminated by the Company on March 31, 2022 were not required to repay any portion of their lump sum retention payments originally received in February 2022. On July 16, 2021, the Company completed a registered direct offering, in which the Company issued and sold 17,416,096 shares of its common stock, pre-funded warrants ("Pre-funded Warrants") to purchase up to an aggregate of 3,941,648 shares of its common stock in lieu of shares of common stock, and warrants ("Warrants") to purchase up to 10,678,872 shares of the Company’s common stock through a securities purchase agreement with several healthcare-focused institutional and accredited investors. The combined price of each share of common stock and accompanying Warrant to purchase one-half of a share of common stock was $1.311 per share. The purchase price of each Pre-funded Warrant was $1.301, which was the combined purchase price per share of common stock and accompanying Warrant to purchase one-half of a share of common stock, minus $0.01. Gross proceeds of the transaction were $28.0 million. As a result of the registered direct offering, the Company received approximately $25.4 million after deducting offering costs. Each Warrant is exercisable for one share of the Company’s common stock at an exercise price of $1.25 per share. The Warrants are immediately exercisable and expire on July 16, 2026. Each Pre-funded Warrant is exercisable for one share of the Company's Common Stock at an exercise price of $0.01 per share. All Pre-funded Warrants were exercised on July 16, 2021. The Company entered into an At Market Issuance Sales Agreement with B. Riley Securities, Inc. (“B. Riley ATM Agreement”) on March 29, 2021. During the year ended December 31, 2021, the Company issued and sold a total of 4,081,338 shares of its common stock under the B. Riley ATM Agreement at a weighted average price of $1.11 per share for net proceeds of approximately $4.2 million. The Company entered into another At Market Issuance Sales Agreement with B. Riley Securities, Inc. (“Updated B. Riley ATM Agreement”) on December 23, 2021. During the first quarter of 2022 through the filing date of this Annual Report, the Company issued and sold 6,804,888 shares of its common stock under the Updated B. Riley ATM Agreement at a weighted average price of $0.62 per share for net proceeds of $4.1 million. The B. Riley ATM Agreement was terminated at the time the Company entered into the Updated B. Riley Agreement. During the first quarter of 2021, the Company issued and sold 6,058,318 shares of its common stock under an At-the Market Equity Offering Sales Agreement with Cowen and Company, LLC ("Cowen ATM Agreement") at a weighted average price of $1.99 per share for net proceeds of $11.7 million. The Cowen ATM Agreement was terminated at the time the Company entered into the B. Riley ATM Agreement. Market volatility resulting from the COVID-19 pandemic or other factors could also adversely impact the Company’s ability to access capital as and when needed. If the Company is unable to obtain sufficient additional funds on commercially acceptable terms to fund its operations, it will have a material adverse effect on its business, results of operations and financial condition and jeopardize its ability to continue operations. The Company may need to implement additional cost reduction strategies, which may include amending, delaying, limiting, reducing, or terminating one or more of its ongoing or planned clinical trials or development programs of its product candidates, and the Company may need to seek an in-court or out-of-court restructuring of its liabilities. In the event of such future liquidation or bankruptcy proceeding, holders of the Company's common stock and other securities will likely suffer a total loss of their investment. These factors raise substantial doubt about the Company’s ability to continue as a going concern as of the filing date of this Annual Report. The accompanying consolidated financial statements have been prepared on a going concern basis, which contemplates the realization of assets and satisfaction of liabilities in the ordinary course of business. The consolidated financial statements do not include any adjustments relating to the recoverability and classification of recorded asset amounts or the amounts and classification of liabilities that might result from the outcome of this uncertainty. Basis of Presentation The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative United States generally accepted accounting principles as found in the Accounting Standard Codification (“ASC”) and Accounting Standards Updates (“ASU”) of the Financial Accounting Standards Board (“FASB”).

Allena Pharmaceuticals, Inc. (the “Company”) is a clinical stage company focused on developing non-absorbed oral enzyme therapeutics to treat metabolic conditions including hyperoxaluria and hyperuricemia. The Company was incorporated under the laws of the State of Delaware on June 24, 2011. The Company’s headquarters are in Newton, Massachusetts.

The Company is subject to risks common to companies in the biotechnology industry, including but not limited to, risks of failure of preclinical studies and clinical trials, the need to obtain marketing approval for any drug product candidate that it may identify and develop, the need to successfully commercialize and gain market acceptance of its product candidates, dependence on key personnel, protection of proprietary technology, compliance with government regulations, development by competitors of technological innovations, reliance on third party manufacturers, ability to transition from pilot-scale manufacturing to large-scale production of products and the need to obtain adequate additional financing to fund the development of its product candidates.

The Company had an accumulated deficit of $246.5 million at December 31, 2021 and will require substantial additional capital to fund operations. The future success of the Company is dependent on its ability to identify and develop its product candidates and ultimately upon its ability to attain profitable operations. At December 31, 2021, the Company had $30.0 million of cash and cash equivalents.

The Company’s available cash and cash equivalents as of December 31, 2021 are not sufficient to fund the Company’s current operating plan for at least the next twelve months following the filing of this Annual Report. The Company requires additional capital to sustain its operations, including its ALLN-346 development program. Management is exploring opportunities to secure additional funding through equity or debt financings or through collaborations, licensing transactions or other sources. In January 2022, the Company initiated a process to explore a range of strategic and financing alternatives to maximize shareholder value and has engaged the investment bank Stifel, Nicolaus & Company, Inc. ("Stifel") to act as strategic advisor for this process. Potential strategic alternatives that may be evaluated include a partnership or sale of ALLN-346, a sale or merger of the Company, or securing additional financing to enable further development of the Company's ALLN-346 program. There can be no assurance that this strategic review process will result in the Company pursuing any transaction or that any transaction, if pursued, will be completed. If the Company is unable to complete a transaction, it may be required to initiate a bankruptcy process.

As part of the strategic process, the Compensation Committee of the Board of Directors approved a retention plan on January 28, 2022, available to all employees ("Retention Plan"). Employees were required to execute retention agreements to receive payments and other considerations offered by the Retention Plan. Employees who executed a retention agreement received a salary adjustment equal to 6.5% retroactive to January 1, 2022, a restricted stock unit ("RSU") grant and a lump sum retention payment. A total of 3,163,000 RSUs were granted on February 1, 2022 under the Retention Plan. The RSUs vest over a three-year period ratably on July 15th and January 15th of each year following grant date. Lump sum retention payments totaling $3.0 million were made to employees in February 2022. If an employee resigns from the Company or is terminated for cause prior to June 30, 2022, the employee would be required to fully repay the lump sum retention payment received. If an employee resigns from the Company or is terminated for cause between July 1, 2022 and September 30, 2022, the employee would be required to repay 50% of the lump sum retention payment received.

During the first quarter of 2022, the Company made principal prepayments of $5.0 million of the $10.0 million that was outstanding as of December 31, 2021 under the loan and security agreement with Pontifax Medison Finance (Israel) L.P. and Pontifax Medison Finance (Cayman) L.P. (together “Pontifax”) (“Pontifax Agreement”). The outstanding principal balance as of the filing date of this Annual Report is $5.0 million. The Company also purchased Directors' & Officers' run-off insurance for $6.8 million in March 2022 to provide continued insurance coverage through any bankruptcy process with run off period of six years, which equal to the statute of limitations.

On March 18, 2022, the Company announced that it was terminating its URIROX-2 study and reloxaliase program and initiated the process of closing the URIROX-2 study with the CRO, investigative sites, patients and business

partners. In connection with the termination of the reloxaliase program, the Company completed a workforce reduction of approximately 40% on March 31, 2022. In accordance with the terms of the Retention Plan, the employees terminated by the Company on March 31, 2022 were not required to repay any portion of their lump sum retention payments originally received in February 2022.

On July 16, 2021, the Company completed a registered direct offering, in which the Company issued and sold 17,416,096 shares of its common stock, pre-funded warrants ("Pre-funded Warrants") to purchase up to an aggregate of 3,941,648 shares of its common stock in lieu of shares of common stock, and warrants ("Warrants") to purchase up to 10,678,872 shares of the Company’s common stock through a securities purchase agreement with several healthcare-focused institutional and accredited investors. The combined price of each share of common stock and accompanying Warrant to purchase one-half of a share of common stock was $1.311 per share. The purchase price of each Pre-funded Warrant was $1.301, which was the combined purchase price per share of common stock and accompanying Warrant to purchase one-half of a share of common stock, minus $0.01. Gross proceeds of the transaction were $28.0 million. As a result of the registered direct offering, the Company received approximately $25.4 million after deducting offering costs. Each Warrant is exercisable for one share of the Company’s common stock at an exercise price of $1.25 per share. The Warrants are immediately exercisable and expire on July 16, 2026. Each Pre-funded Warrant is exercisable for one share of the Company's Common Stock at an exercise price of $0.01 per share. All Pre-funded Warrants were exercised on July 16, 2021.

The Company entered into an At Market Issuance Sales Agreement with B. Riley Securities, Inc. (“B. Riley ATM Agreement”) on March 29, 2021. During the year ended December 31, 2021, the Company issued and sold a total of 4,081,338 shares of its common stock under the B. Riley ATM Agreement at a weighted average price of $1.11 per share for net proceeds of approximately $4.2 million.

The Company entered into another At Market Issuance Sales Agreement with B. Riley Securities, Inc. (“Updated B. Riley ATM Agreement”) on December 23, 2021. During the first quarter of 2022 through the filing date of this Annual Report, the Company issued and sold 6,804,888 shares of its common stock under the Updated B. Riley ATM Agreement at a weighted average price of $0.62 per share for net proceeds of $4.1 million. The B. Riley ATM Agreement was terminated at the time the Company entered into the Updated B. Riley Agreement.

During the first quarter of 2021, the Company issued and sold 6,058,318 shares of its common stock under an At-the Market Equity Offering Sales Agreement with Cowen and Company, LLC ("Cowen ATM Agreement") at a weighted average price of $1.99 per share for net proceeds of $11.7 million. The Cowen ATM Agreement was terminated at the time the Company entered into the B. Riley ATM Agreement.

Market volatility resulting from the COVID-19 pandemic or other factors could also adversely impact the Company’s ability to access capital as and when needed. If the Company is unable to obtain sufficient additional funds on commercially acceptable terms to fund its operations, it will have a material adverse effect on its business, results of operations and financial condition and jeopardize its ability to continue operations. The Company may need to implement additional cost reduction strategies, which may include amending, delaying, limiting, reducing, or terminating one or more of its ongoing or planned clinical trials or development programs of its product candidates, and the Company may need to seek an in-court or out-of-court restructuring of its liabilities. In the event of such future liquidation or bankruptcy proceeding, holders of the Company's common stock and other securities will likely suffer a total loss of their investment. These factors raise substantial doubt about the Company’s ability to continue as a going concern as of the filing date of this Annual Report. The accompanying consolidated financial statements have been prepared on a going concern basis, which contemplates the realization of assets and satisfaction of liabilities in the ordinary course of business. The consolidated financial statements do not include any adjustments relating to the recoverability and classification of recorded asset amounts or the amounts and classification of liabilities that might result from the outcome of this uncertainty.

Basis of Presentation

The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative United States generally accepted accounting principles as found in the Accounting Standard Codification (“ASC”) and Accounting Standards Updates (“ASU”) of the Financial Accounting Standards Board (“FASB”).