Revenue Sources that Account for Greater than 10 Percent of Total Revenue (Detail) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Revenue, Major Customer [Line Items]
Revenue	$ 3,835,006	$ 6,702,561	$ 7,816,651	$ 12,630,136
GlaxoSmithKline and GlaxoSmithKline Biologicals
Revenue, Major Customer [Line Items]
Revenue	235,917	3,080,349	955,004	5,581,038
Percent of Total Revenue	6.00%	46.00%	12.00%	44.00%
Net Medicare revenue
Revenue, Major Customer [Line Items]
Revenue	$ 1,306,989	$ 1,307,906	$ 2,767,307	$ 2,456,869
Percent of Total Revenue	34.00%	20.00%	35.00%	19.00%