Subsequent Events (Details) (USD $)	6 Months Ended		2 Months Ended	4 Months Ended	1 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Mar. 04, 2014 June 2012 Controlled Equity Offering Sales Agreement	Jun. 30, 2014 June 2012 Controlled Equity Offering Sales Agreement	Aug. 10, 2014 Subsequent Event June 2012 Controlled Equity Offering Sales Agreement
Subsequent events
Common stock sold by the entity (in shares)			3,644,143	273,006	685,781
Gross proceeds from sale of common stock by the entity	$ 22,795,000	$ 94,734,000	$ 21,200,000	$ 1,578,260	$ 2,800,000
Common stock, average selling price (in dollars per share)			$ 5.82	$ 5.78	$ 4.10
Amount of common stock available for sale under agreement					$ 45,600,000