Organization and Basis of Presentation	6 Months Ended
Mar. 31, 2013
Accounting Policies [Abstract]
Organization and Basis of Presentation	NOTE 1. *ORGANIZATION AND BASIS OF PRESENTATION* Nature of Business Arrowhead Research Corporation is a clinical stage targeted therapeutics company with development programs in oncology, obesity, and chronic hepatitis B virus infection. Our novel delivery technologies have the potential to enable revolutionary new classes of drugs, such as RNAi interference and peptide drug conjugates, for a broad range of unmet medical needs. Our pipeline of targeted therapeutics are designed to have increased effectiveness through guided delivery and decreased toxicity through reduction of side effects associated with unwanted exposure in healthy cells and tissues. Financing and Liquidity The Company has historically financed its operations through the sale of equity securities of Arrowhead or its Subsidiaries. Development activities have required significant capital investment since the Company’s inception and we expect our current operations to continue to require cash investment in fiscal 2013 and beyond to continue development. At March 31, 2013, the Company had $3.3 million in cash to fund operations. During the six months ended March 31, 2013, the Company’s cash position remained relatively constant. During the six months ended March 31, 2013, the Company received $7.2 million from the issuance of equity, net of fees. Other cash collections were $1.6 million. The company had cash outflow of $8.8 million related to its continuing operating activities. In September 2011, the Company entered into an equity line facility whereby it has the ability to draw capital up to $15 million, subject to certain provisions, including maintaining a minimum stock price of $2.00 per share. During fiscal 2012, the Company drew $1 million from this facility. During fiscal 2013, the Company has not made any draws on this facility. In December 2012, the Company sold 1.8 million units at a price of $2.26 per unit in a public offering. Each unit consisted of one share of Common Stock and a warrant to purchase 0.5 share of Common Stock. The exercise price of these warrants was $2.12 as of March 31, 2013, subsequently adjusted to $1.83. Proceeds net of expenses from the offering were $3.9 million. In January 2013, the Company sold 1.7 million units at a price of $2.12 per unit in a public offering. Each unit consisted of one share of Common Stock and a warrant to purchase 0.5 share of Common Stock. The exercise price of these warrants was $2.14 as of March 31, 2013, subsequently adjusted to $1.83. Proceeds net of expenses from the offering were $3.3 million. In May 2013, the Company sold 14.3 million shares of Arrowhead common stock at a price of $1.83 per share, and 9,900 shares of Arrowhead series B convertible preferred stock at a price of $1,000 per share. The series B preferred stock is convertible into common stock at a conversion price of $1.83. Gross proceeds were $36 million. Basis of Presentation and Principles of Consolidation The accompanying unaudited consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) for interim financial information and in accordance with the instructions to Form 10-Q and Article 8 of Regulation S-X. Accordingly, the financial statements do not include all of the information and notes required by GAAP for complete financial statements. In the opinion of management, all adjustments, including normal recurring accruals, considered necessary for a fair presentation have been included. Interim results are not necessarily indicative of results for a full year. The September 30, 2012 balance sheet was derived from audited financial statements, but does not include all disclosures required by GAAP. This financial information should be read in conjunction with the consolidated financial statements and notes included in the Company’s Annual Report on Form 10-K for the year ended September 30, 2012. The consolidated financial statements of the Company include the accounts of Arrowhead and its wholly-owned and majority-owned Subsidiaries. Prior to April 2008, Arrowhead’s Subsidiaries included Insert Therapeutics, Inc. (“Insert”), which was merged with Calando in April 2008. The merged entity is majority-owned by Arrowhead and continues to operate under the name of Calando. Arrowhead sold its interests in Unidym and Tego in 2011 and 2009, respectively. Unidym and Tego results are included in the Income (Loss) from Discontinued Operations. Income (Loss) from Discontinued Operations also includes Aonex Technologies, Inc. (“Aonex”), sold in 2008 and Nanotechnica, Inc. (“Nanotechnica”), dissolved in 2005. All significant intercompany accounts and transactions are eliminated in consolidation, and noncontrolling interests are accounted for in the Company’s financial statements. Certain reclassifications have been made to prior period financial statements to conform to the current period presentation. Use of Estimates The preparation of financial statements in conformity with generally accepted accounting principles requires management to make estimates and assumptions that affect the amounts reported in the accompanying financial statements. Actual results could differ from those estimates. Reverse Stock Split As of November 17, 2011, the Company effected a 1 for 10 reverse stock split. As a result of the reverse stock split, each ten shares of the Company’s Common Stock issued and outstanding immediately prior to the reverse stock split were combined into one share of Common Stock. Also, as a result of the reverse stock split, the per share exercise price, and the number of shares of Common Stock underlying Company stock options, warrants, and any Common Stock based equity grants outstanding immediately prior to the reverse stock split was proportionally adjusted, based on the one-for-ten split ratio, in accordance with the terms of such options, warrants or other Common Stock based equity grants as the case may be. No fractional shares of Common Stock were issued in connection with the reverse split. Stockholders received a cash payment in lieu of any fractional shares. All share and per share amounts in these financial statements have been retrospectively adjusted to reflect the reverse stock split. Unless otherwise noted, all impacted information has been retroactively adjusted to reflect this reverse stock split. Recently Issued Accounting Standards In July 2012, the FASB issued ASU 2012-02, Testing Indefinite-Lived Intangible Assets for Impairment, which amended the guidance in ASU 2011-08 to simplify the testing of indefinite-lived intangible assets other than goodwill for impairment. ASU 2012-02 becomes effective for annual and interim impairment tests performed for fiscal years beginning on or after September 15, 2012 and earlier adoption is permitted. We adopted this standard in the third quarter of fiscal year 2012. We believe adoption did not have a material effect on our financial statements. In September 2011, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2011-08, Intangibles – Goodwill and Other (Topic 350) – Testing Goodwill for Impairment (ASU 2011-08), to allow entities to use a qualitative approach to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying value. If after performing the qualitative assessment an entity determines it is not more likely than not that the fair value of a reporting unit is less than its carrying amount, then performing the two-step goodwill impairment test is unnecessary. However, if an entity concludes otherwise, then it is required to perform the first step of the two-step goodwill impairment test. ASU 2011-08 is effective for us in fiscal 2013 and earlier adoption is permitted. The adoption of ASU 2011-08 is not anticipated to have any impact on our financial position, results of operations or cash flows. In May 2011, the Financial Accounting Standards Board (“FASB”) issued ASU 2011-04, Fair Value Measurement (“ASU 2011- 04”), which amended ASC 820, Fair Value Measurements (“ASC 820”), providing a consistent definition and measurement of fair value, as well as similar disclosure requirements between U.S. GAAP and International Financial Reporting Standards. ASU 2011-04 changes certain fair value measurement principles, clarifies the application of existing fair value measurement and expands the disclosure requirements. ASU 2011-04 was effective for us beginning January 1, 2012. The adoption of ASU 2011-04 did not have a material effect on our consolidated financial statements or disclosures.

NOTE 1. ORGANIZATION AND BASIS OF PRESENTATION

Nature of Business

Arrowhead Research Corporation is a clinical stage targeted therapeutics company with development programs in oncology, obesity, and chronic hepatitis B virus infection. Our novel delivery technologies have the potential to enable revolutionary new classes of drugs, such as RNAi interference and peptide drug conjugates, for a broad range of unmet medical needs. Our pipeline of targeted therapeutics are designed to have increased effectiveness through guided delivery and decreased toxicity through reduction of side effects associated with unwanted exposure in healthy cells and tissues.

Financing and Liquidity

The Company has historically financed its operations through the sale of equity securities of Arrowhead or its Subsidiaries. Development activities have required significant capital investment since the Company’s inception and we expect our current operations to continue to require cash investment in fiscal 2013 and beyond to continue development.

At March 31, 2013, the Company had $3.3 million in cash to fund operations. During the six months ended March 31, 2013, the Company’s cash position remained relatively constant. During the six months ended March 31, 2013, the Company received $7.2 million from the issuance of equity, net of fees. Other cash collections were $1.6 million. The company had cash outflow of $8.8 million related to its continuing operating activities.

In September 2011, the Company entered into an equity line facility whereby it has the ability to draw capital up to $15 million, subject to certain provisions, including maintaining a minimum stock price of $2.00 per share. During fiscal 2012, the Company drew $1 million from this facility. During fiscal 2013, the Company has not made any draws on this facility.

In December 2012, the Company sold 1.8 million units at a price of $2.26 per unit in a public offering. Each unit consisted of one share of Common Stock and a warrant to purchase 0.5 share of Common Stock. The exercise price of these warrants was $2.12 as of March 31, 2013, subsequently adjusted to $1.83. Proceeds net of expenses from the offering were $3.9 million.

In January 2013, the Company sold 1.7 million units at a price of $2.12 per unit in a public offering. Each unit consisted of one share of Common Stock and a warrant to purchase 0.5 share of Common Stock. The exercise price of these warrants was $2.14 as of March 31, 2013, subsequently adjusted to $1.83. Proceeds net of expenses from the offering were $3.3 million.

In May 2013, the Company sold 14.3 million shares of Arrowhead common stock at a price of $1.83 per share, and 9,900 shares of Arrowhead series B convertible preferred stock at a price of $1,000 per share. The series B preferred stock is convertible into common stock at a conversion price of $1.83. Gross proceeds were $36 million.

Basis of Presentation and Principles of Consolidation

The accompanying unaudited consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) for interim financial information and in accordance with the instructions to Form 10-Q and Article 8 of Regulation S-X. Accordingly, the financial statements do not include all of the information and notes required by GAAP for complete financial statements. In the opinion of management, all adjustments, including normal recurring accruals, considered necessary for a fair presentation have been included. Interim results are not necessarily indicative of results for a full year. The September 30, 2012 balance sheet was derived from audited financial statements, but does not include all disclosures required by GAAP. This financial information should be read in conjunction with the consolidated financial statements and notes included in the Company’s Annual Report on Form 10-K for the year ended September 30, 2012.

The consolidated financial statements of the Company include the accounts of Arrowhead and its wholly-owned and majority-owned Subsidiaries. Prior to April 2008, Arrowhead’s Subsidiaries included Insert Therapeutics, Inc. (“Insert”), which was merged with Calando in April 2008. The merged entity is majority-owned by Arrowhead and continues to operate under the name of Calando. Arrowhead sold its interests in Unidym and Tego in 2011 and 2009, respectively. Unidym and Tego results are included in the Income (Loss) from Discontinued Operations. Income (Loss) from Discontinued Operations also includes Aonex Technologies, Inc. (“Aonex”), sold in 2008 and Nanotechnica, Inc. (“Nanotechnica”), dissolved in 2005. All significant intercompany accounts and transactions are eliminated in consolidation, and noncontrolling interests are accounted for in the Company’s financial statements. Certain reclassifications have been made to prior period financial statements to conform to the current period presentation.

Use of Estimates

The preparation of financial statements in conformity with generally accepted accounting principles requires management to make estimates and assumptions that affect the amounts reported in the accompanying financial statements. Actual results could differ from those estimates.

Reverse Stock Split

As of November 17, 2011, the Company effected a 1 for 10 reverse stock split. As a result of the reverse stock split, each ten shares of the Company’s Common Stock issued and outstanding immediately prior to the reverse stock split were combined into one share of Common Stock. Also, as a result of the reverse stock split, the per share exercise price, and the number of shares of Common Stock underlying Company stock options, warrants, and any Common Stock based equity grants outstanding immediately prior to the reverse stock split was proportionally adjusted, based on the one-for-ten split ratio, in accordance with the terms of such options, warrants or other Common Stock based equity grants as the case may be. No fractional shares of Common Stock were issued in connection with the reverse split. Stockholders received a cash payment in lieu of any fractional shares. All share and per share amounts in these financial statements have been retrospectively adjusted to reflect the reverse stock split. Unless otherwise noted, all impacted information has been retroactively adjusted to reflect this reverse stock split.

Recently Issued Accounting Standards

In July 2012, the FASB issued ASU 2012-02, Testing Indefinite-Lived Intangible Assets for Impairment, which amended the guidance in ASU 2011-08 to simplify the testing of indefinite-lived intangible assets other than goodwill for impairment. ASU 2012-02 becomes effective for annual and interim impairment tests performed for fiscal years beginning on or after September 15, 2012 and earlier adoption is permitted. We adopted this standard in the third quarter of fiscal year 2012. We believe adoption did not have a material effect on our financial statements.

In September 2011, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2011-08, Intangibles – Goodwill and Other (Topic 350) – Testing Goodwill for Impairment (ASU 2011-08), to allow entities to use a qualitative approach to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying value. If after performing the qualitative assessment an entity determines it is not more likely than not that the fair value of a reporting unit is less than its carrying amount, then performing the two-step goodwill impairment test is unnecessary. However, if an entity concludes otherwise, then it is required to perform the first step of the two-step goodwill impairment test. ASU 2011-08 is effective for us in fiscal 2013 and earlier adoption is permitted. The adoption of ASU 2011-08 is not anticipated to have any impact on our financial position, results of operations or cash flows.

In May 2011, the Financial Accounting Standards Board (“FASB”) issued ASU 2011-04, Fair Value Measurement (“ASU 2011- 04”), which amended ASC 820, Fair Value Measurements (“ASC 820”), providing a consistent definition and measurement of fair value, as well as similar disclosure requirements between U.S. GAAP and International Financial Reporting Standards. ASU 2011-04 changes certain fair value measurement principles, clarifies the application of existing fair value measurement and expands the disclosure requirements. ASU 2011-04 was effective for us beginning January 1, 2012. The adoption of ASU 2011-04 did not have a material effect on our consolidated financial statements or disclosures.