CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME/LOSS (USD $)	3 Months Ended									6 Months Ended		9 Months Ended		12 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Jun. 30, 2012	Jun. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Revenues
Research and Development Revenue	$ 1,465,752	$ 2,514,000	$ 2,289,820	$ 2,701,164	$ 1,466,000	$ 4,960,000	$ 3,577,948	$ 2,491,056	$ 1,696,721	$ 4,166,916	$ 4,187,777	$ 6,456,736	$ 7,765,725	$ 8,970,835	$ 12,725,792	$ 19,215,837
Operating expenses
Selling, general and administrative		2,583,000	3,139,000	3,475,000	2,214,000	6,363,000	3,969,000	9,351,000	4,250,000					11,410,131	23,931,713	8,130,669
Research and development		4,396,000	4,170,000	5,183,000	4,465,000	5,795,000	5,170,000	3,835,000	3,566,000					18,213,036	18,367,348	22,658,959
Patent preparation fees		794,000	377,000	376,000	336,000	571,000	482,000	413,000	342,000					1,883,405	1,808,168	1,148,597
Total operating expenses	7,014,713		7,685,619	9,033,527			9,621,092	13,598,975	8,158,161	16,048,240	21,757,135	23,733,861	31,378,228	31,506,572	44,107,229	31,938,225
Operating loss	(5,548,961)	(5,259,000)	(5,395,799)	(6,332,363)	(5,549,000)	(7,769,000)	(6,043,144)	(11,107,919)	(6,461,440)	(11,881,324)	(17,569,358)	(17,277,125)	(23,612,503)	(22,535,737)	(31,381,437)	(12,722,388)
Decrease (increase) in fair value of common stock warrants	(999,529)		(133,375)	904,731			12,841,849	5,543,721	4,952,670	(94,798)	10,496,391	(228,173)	23,338,240	804,516	24,436,309	(38,110,030)
Interest expense														(172,993)	0	0
Other income, net														522	13,061	659,292
Loss before income taxes														(21,903,692)	(6,932,067)	(50,173,126)
Benefit from (provision for) income taxes	1,932,719		2,470,346	1,660,720			1,527,275	32,907,988	1,511,563	3,593,439	32,895,101	6,063,785	34,422,376	7,844,153	36,031,646	(175,175)
Net income (loss)	(4,615,609)	(2,618,000)	(3,058,734)	(3,766,838)	(4,616,000)	(5,061,000)	8,326,309	27,345,796	(1,512,000)	(8,382,447)	25,834,234	(11,441,183)	34,160,542	(14,059,539)	29,099,579	(50,348,301)
Earning (loss) per share: basic		$ (0.04)	$ (0.06)	$ (0.07)	$ (0.09)	$ (0.11)	$ 0.16	$ 0.54	$ (0.03)		$ 0.51		$ 0.67	$ (0.27)	$ 0.57	$ (1.12)
Earnings (loss) per share: diluted		$ (0.04)	$ (0.06)	$ (0.07)	$ (0.09)	$ (0.11)	$ 0.11	$ 0.40	$ (0.03)		$ 0.28		$ 0.20	$ (0.27)	$ 0.09	$ (1.12)
Weighted average shares: basic							50,806,284	50,879,599			50,422,014		50,739,475	51,639,622	50,929,491	45,151,774
Weighted average shares outstanding: diluted							51,987,253	54,671,403			54,507,838		54,234,977	51,639,622	54,061,650	45,151,774
Comprehensive income (loss)
Change in net unrealized gain (loss) on short-term investments														0	(4,067)	4,067
Comprehensive income (loss)														$ (14,059,539)	$ 29,095,512	$ (50,344,234)