Liquidity	12 Months Ended
Dec. 31, 2011
Liquidity [Abstract]
Liquidity	5. LIQUIDITY Since its inception in 1980, the Company has incurred losses of approximately $310.0 million, substantially all of which resulted from expenditures related to research and development, general and administrative charges and acquired in-process research and development resulting from two acquisitions. The Company has not generated any material revenue from product sales to date, and there can be no assurance that revenues from product sales will be achieved. Moreover, even if the Company does achieve revenue from product sales, the Company expects to incur operating losses over the next several years. The Company believes it has sufficient cash to fund operations at least through the following 12 months. The Company anticipates receiving continued funding from the U.S. government to pursue the development of its therapeutics against Ebola and Marburg, and has assumed certain revenues from these awards in providing this guidance. Should the Company's funding from the U.S. government cease or be delayed, it would have a significant negative impact on the Company's financial condition and on this guidance and the Company would likely be forced to significantly curtail its research and development efforts unless additional funding was obtained. The Company is also likely to pursue additional funding through public or private financings and cash generated from establishing collaborations or licensing its technology to other companies. At December 31, 2011, cash and cash equivalents were $39.9 million, compared to $33.6 million at December 31, 2010. The Company's principal sources of liquidity have been equity financings and revenue from its U.S. government research contracts and grants. The Company's principal uses of cash have been research and development expenses, general and administrative expenses and other working capital requirements. In the periods presented, nearly all of the revenue generated by the Company was derived from research contracts with and grants from the U.S. government. As of December 31, 2011, the Company had substantially completed all of its contracts with the U.S. government except for the July 2010 agreement for the development of therapeutics against Ebola and Marburg. Pursuant to this agreement, as of December 31, 2011, the Company is currently entitled to receive up to $126.5 million of which $52.7 million has been recognized as revenue. In addition, if the U.S. government elects to exercise all its options under the agreement, an additional $161.5 million in funding is available. See "Note 7—U.S. Government Contracts" for additional information. In December 2007 and January and August 2009, the Company sold shares of its common stock and also issued warrants to purchase shares of its common stock in offerings registered under the Securities Act of 1933 (the "Securities Act"). Additionally, in April 2011, the Company sold shares of its common stock in an offering registered under the Securities Act. See "Note 6—Equity Financing" for more information. The likelihood of the long-term success of the Company must be considered in light of the expenses, difficulties and delays frequently encountered in the development and commercialization of new pharmaceutical products, competitive factors in the marketplace, the risks associated with U.S. government sponsored programs, and the complex regulatory environment in which the Company operates. There can be no assurance that the Company will ever achieve significant revenues or profitable operations.

5. LIQUIDITY

Since its inception in 1980, the Company has incurred losses of approximately $310.0 million, substantially all of which resulted from expenditures related to research and development, general and administrative charges and acquired in-process research and development resulting from two acquisitions. The Company has not generated any material revenue from product sales to date, and there can be no assurance that revenues from product sales will be achieved. Moreover, even if the Company does achieve revenue from product sales, the Company expects to incur operating losses over the next several years.

The Company believes it has sufficient cash to fund operations at least through the following 12 months. The Company anticipates receiving continued funding from the U.S. government to pursue the development of its therapeutics against Ebola and Marburg, and has assumed certain revenues from these awards in providing this guidance. Should the Company's funding from the U.S. government cease or be delayed, it would have a significant negative impact on the Company's financial condition and on this guidance and the Company would likely be forced to significantly curtail its research and development efforts unless additional funding was obtained. The Company is also likely to pursue additional funding through public or private financings and cash generated from establishing collaborations or licensing its technology to other companies.

At December 31, 2011, cash and cash equivalents were $39.9 million, compared to $33.6 million at December 31, 2010. The Company's principal sources of liquidity have been equity financings and revenue from its U.S. government research contracts and grants. The Company's principal uses of cash have been research and development expenses, general and administrative expenses and other working capital requirements.

In the periods presented, nearly all of the revenue generated by the Company was derived from research contracts with and grants from the U.S. government. As of December 31, 2011, the Company had substantially completed all of its contracts with the U.S. government except for the July 2010 agreement for the development of therapeutics against Ebola and Marburg. Pursuant to this agreement, as of December 31, 2011, the Company is currently entitled to receive up to $126.5 million of which $52.7 million has been recognized as revenue. In addition, if the U.S. government elects to exercise all its options under the agreement, an additional $161.5 million in funding is available. See "Note 7—U.S. Government Contracts" for additional information.

In December 2007 and January and August 2009, the Company sold shares of its common stock and also issued warrants to purchase shares of its common stock in offerings registered under the Securities Act of 1933 (the "Securities Act"). Additionally, in April 2011, the Company sold shares of its common stock in an offering registered under the Securities Act. See "Note 6—Equity Financing" for more information.

The likelihood of the long-term success of the Company must be considered in light of the expenses, difficulties and delays frequently encountered in the development and commercialization of new pharmaceutical products, competitive factors in the marketplace, the risks associated with U.S. government sponsored programs, and the complex regulatory environment in which the Company operates. There can be no assurance that the Company will ever achieve significant revenues or profitable operations.