Government Contracts - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		1 Months Ended	3 Months Ended		9 Months Ended		3 Months Ended	9 Months Ended		0 Months Ended	3 Months Ended	9 Months Ended	1 Months Ended	3 Months Ended		9 Months Ended		3 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 July 2010 Agreement (Ebola and Marburg IV) [Member]	Sep. 30, 2013 July 2010 Agreement (Ebola and Marburg IV) [Member]	Sep. 30, 2014 July 2010 Agreement (Ebola and Marburg IV) [Member] Segment	Sep. 30, 2013 July 2010 Agreement (Ebola and Marburg IV) [Member]	Jul. 31, 2013 July 2013 Children's National Medical Center Agreement (DMD) [Member]	Sep. 30, 2014 July 2013 Children's National Medical Center Agreement (DMD) [Member]	Sep. 30, 2013 July 2013 Children's National Medical Center Agreement (DMD) [Member]	Sep. 30, 2014 July 2013 Children's National Medical Center Agreement (DMD) [Member]	Sep. 30, 2013 July 2013 Children's National Medical Center Agreement (DMD) [Member]	Sep. 30, 2014 Carolinas Medical Center Agreement (DMD) [Member]	Sep. 30, 2014 Carolinas Medical Center Agreement (DMD) [Member]	Sep. 30, 2014 Marburg [Member]	Aug. 29, 2012 August 2012 Agreement (Intramuscular) [Member]	Sep. 30, 2013 August 2012 Agreement (Intramuscular) [Member]	Sep. 30, 2013 August 2012 Agreement (Intramuscular) [Member]	Nov. 30, 2012 European Union SKIP-NMD Agreement (DMD) [Member]	Sep. 30, 2014 European Union SKIP-NMD Agreement (DMD) [Member]	Sep. 30, 2013 European Union SKIP-NMD Agreement (DMD) [Member]	Sep. 30, 2014 European Union SKIP-NMD Agreement (DMD) [Member]	Sep. 30, 2013 European Union SKIP-NMD Agreement (DMD) [Member]	Sep. 30, 2014 European Union SKIP-NMD Agreement (DMD) [Member] Maximum [Member]	Sep. 30, 2013 European Union SKIP-NMD Agreement (DMD) [Member] Minimum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of segments							4
Period of performance spanning							4 years
Remaining portion of contract, expiration date																2014-07
Agreement revenue	$ 1,059,000	$ 4,168,000	$ 9,730,000	$ 11,593,000	$ 1,043,000	$ 2,444,000	$ 6,816,000	$ 7,134,000		$ 0	$ 674,000	$ 659,000	$ 674,000	$ 0	$ 850,000			$ 514,000	$ 2,759,000		$ 16,000	$ 536,000	$ 1,405,000	$ 599,000	$ 100,000	$ 500,000
Advance payments received on contracts awarded																	3,900,000
Agreement amount									$ 1,300,000											$ 2,500,000