Consolidated Quarterly Financial Data-Unaudited (Details) (USD $)	3 Months Ended								9 Months Ended	12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Sep. 30, 2012	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Trading Securities and Other Trading Assets
U.S. product sales, net	$ 14,381,000	$ 16,186,000	$ 14,094,000	$ 13,626,000	$ 12,830,000	$ 15,560,000	$ 12,846,000	$ 10,861,000		$ 58,287,000	$ 52,097,000	$ 59,339,000
International product sales and royalties	120,000	(168,000)	168,000							120,000
License fee and other collaboration revenues	6,564,000	1,566,000	16,592,000	1,753,000	1,999,000	1,707,000	2,288,000	2,327,000		26,475,000	8,321,000	6,132,000
Other product sales and royalties	79,000	158,000	158,000	101,000	78,000	288,000	268,000	197,000		496,000	831,000	774,000
Total revenues	21,144,000	17,742,000	31,012,000	15,480,000	14,907,000	17,555,000	15,402,000	13,385,000		85,378,000	61,249,000	66,245,000
Cost of product sales	4,027,000	4,323,000	3,224,000	2,646,000	2,739,000	2,669,000	2,082,000	3,041,000		14,220,000	10,531,000	7,606,000
Operating expenses	20,532,000	17,420,000	22,772,000	25,643,000	28,158,000	32,124,000	33,521,000	33,200,000
Restructuring expenses	595,000	562,000	1,058,000		3,508,000					2,215,000	3,508,000	2,224,000
Interest and dividend income, net	260,000	295,000	338,000	393,000	357,000	378,000	452,000	560,000		1,286,000	1,747,000	1,741,000
(Losses) gains on investments, net	3,000	2,000	(1,471,000)		1,000	14,000	(209,000)	1,000		(1,466,000)	(193,000)	408,000
Income tax benefit	61,000	299,000	494,000		559,000	215,000	396,000			854,000	1,170,000	472,000
Net loss	(3,686,000)	(3,967,000)	3,319,000	(12,416,000)	(18,581,000)	(16,631,000)	(19,562,000)	(22,295,000)		(16,750,000)	(77,069,000)	(81,153,000)
Net income (loss) per share - basic (in dollars per share)	$ (0.17)	$ (0.19)	$ 0.16	$ (0.58)
Net income (loss) per share - diluted (in dollars per share)	$ (0.17)	$ (0.19)	$ 0.15	$ (0.58)
Net income (loss) per share-basic and diluted (in dollars per share)					$ (0.87)	$ (0.78)	$ (0.92)	$ (1.05)		$ (0.78)	$ (3.64)	$ (3.90)
Reduction in estimated Medicaid rebate reserve related to Feraheme sales		600,000				2,500,000			2,200,000	(621,000)	(2,532,000)	(599,000)
Milestone payments revenue recognized under the agreement	5,000,000		15,000,000
ARS portfolio
Trading Securities and Other Trading Assets
(Losses) gains on investments, net			$ 1,500,000							$ 1,500,000