Equity (Details) (Common stock purchase agreement, Aspire Capital, USD $) In Millions, except Share data, unless otherwise specified	0 Months Ended
	Mar. 31, 2013	Jan. 15, 2013
Common Stock Purchase Agreement
Term for purchase of shares by Aspire Capital		2 years
Number of shares of common stock registered on Form S-1 for resale by Aspire		3,000,000
Number of shares of common stock issued to Aspire Capital as commitment fee		80,527
Common stock sold (in shares)	146,886
Common stock sold including commitment shares (in shares)	227,143
Maximum
Common Stock Purchase Agreement
Value of common stock purchase commitment		25.0
Number of shares authorized for sale and issuance (in shares)		1,856,616
Shares authorized for sale and issuance (as a percent)		19.99%