Assignment and License Agreements (Details) (USD $) In Millions, except Share data, unless otherwise specified			12 Months Ended			1 Months Ended			12 Months Ended		12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 1997 GlaxoSmithKline PLC (Glaxo)	Dec. 31, 2012 Pfizer Inc.	Dec. 31, 1996 Pfizer Inc.	Jun. 30, 2006 Supernus Pharmaceuticals, Inc.	Nov. 30, 2008 Eli Lilly and Company	Jul. 31, 2011 Toray Industries, Inc.	Dec. 31, 2007 Toray Industries, Inc.	Dec. 31, 2012 Toray Industries, Inc.	Dec. 31, 2011 Pluristem License Agreement	Aug. 31, 2011 Pluristem License Agreement
Assignment and License Agreements
Minimum term of royalty payment			10 years		10 years	12 years
Reduction in royalty percentage in the event of payment to third party				50.00%
Royalty as a percentage of net sales							5.00%
Common stock issued (in shares)	62,082,007	61,506,063							400,000
Notice period									30 days
Price per share (in dollars per share)									$ 27.21
Non-refundable payments to be made under the license								$ 50.0				$ 7.0
Term of installment payments under license								5 years
Obligation and a corresponding charge to research and development expenses								46.3			5.0
Royalty payments, remaining obligation										$ 30.0