Financing Transactions (Controlled Equity Offering) (Details) (USD $) In Millions, except Share data, unless otherwise specified	9 Months Ended	0 Months Ended	9 Months Ended		0 Months Ended
	Sep. 30, 2014 Subsequent Event	Oct. 03, 2014 Equity Offering [Member]	Sep. 30, 2014 Equity Offering [Member]	Mar. 25, 2013 Equity Offering [Member]	Oct. 03, 2014 Equity Offering [Member] Subsequent Event	Sep. 30, 2014 Amendment to the Controlled Equity Offering [Member]	May 23, 2014 Amendment to the Controlled Equity Offering [Member]
Equity Offering [Line Items]
The maximum value of common stock issuable under the controlled equity offering arrangement				$ 15.0			$ 15.0
Commission owed to sales agent, expressed as percentage of aggregate gross proceeds from each sale of shares of common stock				3.00%
Proceeds from issuance of common stock, net of issuance costs received		0.5	15.5		0.5
Number of shares sold	1,325,863		9,194,591
Amount remaining available under controlled equity offering sale arrangement						$ 5.3