Warrants (Details) (USD $) In Millions, except Share data, unless otherwise specified	6 Months Ended			3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2012 Warrant to Purchase Common Stock [Member]	Sep. 27, 2007 Warrant to Purchase Common Stock [Member]	Jun. 30, 2012 Lender Warrant [Member]	Jun. 30, 2011 Lender Warrant [Member]	Jun. 30, 2012 Lender Warrant [Member]	Jun. 30, 2011 Lender Warrant [Member]	Jun. 30, 2012 Lender Warrant [Member] Redeemable Preferred Stock, Series C [Member]	May 23, 2005 Lender Warrant [Member] Redeemable Preferred Stock, Series C [Member]	May 15, 2012 Lender Warrant [Member] Series C Redeemable Convertible Preferred Stock [Member]	May 15, 2012 Investor Warrants [Member]
Warrants (Textual) [Abstract]
Shares purchased for warrant			75,000						423,529	211,764	4,366,803
Common stock at a purchase price	$ 8.50
Purchase price of stock against warrant			8.20						4.25
Warrants exercisable date		Sep. 26, 2014						May 23, 2015
Fair value of Warrant at the final re-measurement date				$ 0.7		$ 0.7
Recorded a mark-to-market gain				0.4	0.1	0.4
Recorded a mark-to-market loss							$ 0.1
IPO closing date	May 15, 2012
Warrants exercisable period	7 years