Summary of Significant Accounting Policies Revenue (Details) (BARDA Contract)	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
BARDA Contract
Revenue [Line Items]
Concentration risk, percentage	100.00%	96.00%	91.00%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 275

-SubTopic 10

-Section 50

-Paragraph 18

-URI http://asc.fasb.org/extlink&oid=6927468&loc=d3e6351-108592

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

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-Subparagraph (a)

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 275

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-Section 50

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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-Section 50

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-URI http://asc.fasb.org/extlink&oid=7491637&loc=d3e13531-108611

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