Subsequent Events (Details) (USD $) In Thousands, except Share data in Millions, unless otherwise specified	9 Months Ended			1 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 Maximum	Oct. 31, 2012 Regulus Therapeutics Inc. Maximum	Oct. 31, 2012 Subsequent Event Regulus Therapeutics Inc.	Oct. 31, 2012 Subsequent Event Regulus Therapeutics Inc. Maximum
Subsequent Events
Issuance of common stock (in shares)					12.7
Share price of common stock issued by investee (in dollars per share)					$ 4.00
Price of common stock of investee purchased	$ 40	$ 359			$ 3,000
Ratio of common shares received to preferred shares previously held					0.50
Shares owned					7
Ownership percentage after sale			20.00%	20.00%		20.00%