Note 1 - Company Overview	12 Months Ended
Jun. 30, 2013
Disclosure Text Block [Abstract]
Nature of Operations [Text Block]	(1) Company Overview Biota Pharmaceuticals, Inc., together with its wholly owned subsidiaries (“Biota”, or the “Company”) is a biopharmaceutical company focused on the discovery and development of products to prevent and treat serious and potentially life-threatening infectious diseases. The Company has been incorporated in the state of Delaware since 1969 and the corporate headquarters are located in Alpharetta, Georgia. On November 8, 2012, Nabi Biopharmaceuticals (“Nabi”) merged with Biota Holdings Limited, which was previously listed on the Australian Stock Exchange (ASX:BTA), and the resulting company was renamed to Biota Pharmaceuticals, Inc. The Company currently has two Phase 2 clinical-stage product candidates; laninamivir octanoate, which it is developing under an existing contract with the U.S. Office of Biomedical Advanced Research and Development Authority ("BARDA") to provide up to $231.2 million in financial support to complete the clinical development of laninamivir octanoate for the treatment of influenza A and B infections in the U.S. market; and vapendavir, a potent, oral broad-spectrum capsid inhibitor of enteroviruses including human rhinovirus ("HRV"). In addition, the Company has preclinical programs focused on developing treatments for respiratory syncytial virus ("RSV") as well as for gram-negative and multi-drug resistant bacterial infections. The Company has developed a neuraminidase inhibitor, zanamivir, which is marketed worldwide by GlaxoSmithKline (“GSK”) as Relenza® for the prevention and treatment of influenza under a research and license agreement entered into with the Company in 1990. In addition, the Company and Daiichi Sankyo Inc. have cross-licensed the world-wide rights to develop and commercialize long-acting neuraminidase inhibitors (“LANI’s”), including laninamivir octanoate, which is marketed by Daiichi Sankyo Inc. as (“Inavir^®” ) in Japan for the treatment of influenza A & B infections in adults and children. In November 2012, Daiichi Sankyo submitted an application for a label change in Japan to manufacture and market the influenza antiviral product Inavir ® for the prevention of influenza infection. The Company has filed an Investigational New Drug application (“IND”) with the United States Food and Drug Administration (“FDA”) to develop laninamivir octanoate, and in 2011 entered into a contract with BARDA designed to provide up to $231.2 million for the completion of the clinical development and U.S. based manufacturing of laninamivir octanoate for the treatment of influenza A and B infections. Although several of the Company’s influenza products have been successfully developed and commercialized by other larger pharmaceutical companies under license agreements, the Company has not received regulatory approval for any product candidates it has developed independently, and does not have any sales, marketing or commercial capabilities. Therefore, it is possible that the Company may not successfully derive any significant product revenues from any of its existing or future development-stage product candidates. *Merger between Nabi Biopharmaceuticals and Biota Holdings Limited* On November 8, 2012, Nabi and Biota Holdings Limited completed a merger (the “Merger”), and renamed the resulting company Biota Pharmaceuticals, Inc. Former Biota Holdings Limited shareholders retained approximately 83% of the Company’s shares of common stock, while former Nabi shareholders retained approximately 17% as consideration for Nabi’s net assets, the vast majority of which was $27.0 million in net cash on hand on the date of the transaction. As Nabi had minimal ongoing activity with respect to its development programs and related operations at the time of the merger, the Company’s future operations will be largely represented by the operations of Biota Holdings Limited. Further, due to the fact that former Biota Holdings Limited shareholders held a significant majority of the voting interest in the Company upon the completion of the merger, the merger has been accounted for as a “reverse merger”, such that, notwithstanding the fact that Nabi was the legal acquirer, Biota Holdings Limited is considered the accounting acquirer for financial reporting purposes. Accordingly, the financial statements of Biota Holdings Limited are treated as the historical financial statements of the Company, with the operating results of Nabi being included from November 8, 2012. As a result of the reverse merger, the accompanying financial statements share and per share information has been retroactively adjusted to reflect the exchange ratio in the Merger. See Note 3 for additional discussion of the merger.

Note 1 - Company Overview

12 Months Ended

Jun. 30, 2013

(1) Company Overview

Biota Pharmaceuticals, Inc., together with its wholly owned subsidiaries (“Biota”, or the “Company”) is a biopharmaceutical company focused on the discovery and development of products to prevent and treat serious and potentially life-threatening infectious diseases. The Company has been incorporated in the state of Delaware since 1969 and the corporate headquarters are located in Alpharetta, Georgia. On November 8, 2012, Nabi Biopharmaceuticals (“Nabi”) merged with Biota Holdings Limited, which was previously listed on the Australian Stock Exchange (ASX:BTA), and the resulting company was renamed to Biota Pharmaceuticals, Inc.

The Company currently has two Phase 2 clinical-stage product candidates; laninamivir octanoate, which it is developing under an existing contract with the U.S. Office of Biomedical Advanced Research and Development Authority ("BARDA") to provide up to $231.2 million in financial support to complete the clinical development of laninamivir octanoate for the treatment of influenza A and B infections in the U.S. market; and vapendavir, a potent, oral broad-spectrum capsid inhibitor of enteroviruses including human rhinovirus ("HRV"). In addition, the Company has preclinical programs focused on developing treatments for respiratory syncytial virus ("RSV") as well as for gram-negative and multi-drug resistant bacterial infections.

The Company has developed a neuraminidase inhibitor, zanamivir, which is marketed worldwide by GlaxoSmithKline (“GSK”) as Relenza® for the prevention and treatment of influenza under a research and license agreement entered into with the Company in 1990. In addition, the Company and Daiichi Sankyo Inc. have cross-licensed the world-wide rights to develop and commercialize long-acting neuraminidase inhibitors (“LANI’s”), including laninamivir octanoate, which is marketed by Daiichi Sankyo Inc. as (“Inavir^®” ) in Japan for the treatment of influenza A & B infections in adults and children. In November 2012, Daiichi Sankyo submitted an application for a label change in Japan to manufacture and market the influenza antiviral product Inavir ® for the prevention of influenza infection. The Company has filed an Investigational New Drug application (“IND”) with the United States Food and Drug Administration (“FDA”) to develop laninamivir octanoate, and in 2011 entered into a contract with BARDA designed to provide up to $231.2 million for the completion of the clinical development and U.S. based manufacturing of laninamivir octanoate for the treatment of influenza A and B infections.

Although several of the Company’s influenza products have been successfully developed and commercialized by other larger pharmaceutical companies under license agreements, the Company has not received regulatory approval for any product candidates it has developed independently, and does not have any sales, marketing or commercial capabilities. Therefore, it is possible that the Company may not successfully derive any significant product revenues from any of its existing or future development-stage product candidates.

Merger between Nabi Biopharmaceuticals and Biota Holdings Limited

On November 8, 2012, Nabi and Biota Holdings Limited completed a merger (the “Merger”), and renamed the resulting company Biota Pharmaceuticals, Inc. Former Biota Holdings Limited shareholders retained approximately 83% of the Company’s shares of common stock, while former Nabi shareholders retained approximately 17% as consideration for Nabi’s net assets, the vast majority of which was $27.0 million in net cash on hand on the date of the transaction. As Nabi had minimal ongoing activity with respect to its development programs and related operations at the time of the merger, the Company’s future operations will be largely represented by the operations of Biota Holdings Limited. Further, due to the fact that former Biota Holdings Limited shareholders held a significant majority of the voting interest in the Company upon the completion of the merger, the merger has been accounted for as a “reverse merger”, such that, notwithstanding the fact that Nabi was the legal acquirer, Biota Holdings Limited is considered the accounting acquirer for financial reporting purposes. Accordingly, the financial statements of Biota Holdings Limited are treated as the historical financial statements of the Company, with the operating results of Nabi being included from November 8, 2012. As a result of the reverse merger, the accompanying financial statements share and per share information has been retroactively adjusted to reflect the exchange ratio in the Merger. See Note 3 for additional discussion of the merger.