Nature of the Business (Details) (USD $) Share data in Millions, except Per Share data, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Dec. 31, 2011	Jan. 10, 2012 Public Offering in January 2012 [Member]	Jul. 13, 2012 Public Offering in July 2012 [Member]
Nature of Business (Textual) [Abstract]
Accumulated deficit	$ (143,598,000)	$ (115,840,000)
Amount accounted for Business combination through cash and cash equivalents	50,100,000
Closure of underwritten public offering			90,000,000	115,000,000
Shares of common stock offered			3.6	2.8
Price per share of common stock offered			$ 25.18	$ 41.20
Net proceeds from public offering			$ 84,600,000	$ 108,100,000