Sales of Common Stock (Details) (USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended				3 Months Ended
	May 07, 2013	Mar. 31, 2013	Oct. 31, 2012	Jul. 31, 2008	Jun. 30, 2013	Mar. 31, 2013
Units issued in direct offering	1,300,000	200,000		6,686,650		3,300,000
Equity issuance, price per share				$ 2.68
Proceeds from direct offering	$ 3.2			$ 17.5	$ 0.4	$ 6.4
Common stock authorized for issuance under current shelf registration statement with SEC, dollar amount		200
Common stock authorized for issuance under prior shelf registration statement with SEC, dollar amount			$ 50
Minimum [Member]
Equity issuance, price per share						$ 2.06
Maximum [Member]
Equity issuance, price per share						$ 2.18