Condensed Statements of Cash Flows (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Net cash used in operating activities	$ 48,729,569	$ 33,377,997	$ 29,704,698
Net cash provided by (used in) investing activities	(9,365,100)	(20,309,900)	(12,044,070)
Net cash (used in) provided by financing activities	(992,846)	(2,550,960)	35,870,817
CASH AND CASH EQUIVALENTS, at the beginning of the year	105,637,627	90,609,340	34,614,838
CASH AND CASH EQUIVALENTS, at the end of the year	144,300,290	105,637,627	90,609,340
Parent Company
Net cash used in operating activities	(3,333,914)	(2,267,880)	(2,911,720)
Net cash provided by (used in) investing activities	4,390,775	2,496,427	(32,959,097)
Net cash (used in) provided by financing activities	(992,846)	(228,547)	35,870,817
CASH AND CASH EQUIVALENTS, at the beginning of the year	0	0	0
CASH AND CASH EQUIVALENTS, at the end of the year	$ 64,015	$ 0	$ 0