Sales of Common Stock (Details) (USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended				3 Months Ended	9 Months Ended	32 Months Ended
	Oct. 31, 2012	May 31, 2012	Dec. 31, 2011	Jul. 31, 2008	Mar. 31, 2012	Sep. 30, 2012	Nov. 07, 2012
Sales of Common Stock [Abstract]
Common stock sold	12,385,321	10,000,000	700,000	6,686,650		8,400,000	24,957,715
Common stock, price per share	$ 2.18	$ 1.22
Proceeds from sale of stock		$ 12.1		$ 17.5	$ 0.8	$ 14.0	$ 49.9
Gross proceeds authorized in sale of stock						50.0
Gross proceeds authorized in sale of stock, prior sales agreement						$ 50.0
Average sales price						$ 1.70