Contract Revenue - Additional Information (Detail) (USD $)	1 Months Ended	3 Months Ended	12 Months Ended
	Nov. 30, 2012 European Union Agreement	Mar. 31, 2013 European Union Agreement	Mar. 31, 2013 July 2010 Contract (Ebola and Marburg IV) Segment	Mar. 31, 2013 Phase two three four Marburg	Aug. 29, 2012 August 2012 Contract (Intramuscular administration)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of segments			4
Period of performance spanning			4 years
Estimated funding				$ 84,400,000
Funding to evaluate the feasibility of intramuscular route of administration					3,900,000
Aggregate amount for research granted	2,500,000	635,000
Aggregate potential funding period	3 years
Revenue recognized from research grant		54,000
Deferred revenue		$ 581,000