Summary of Warrants by Year of Expiration (Details) (USD $)	3 Months Ended
	Mar. 31, 2015
Class Of Warrant Or Right [Line Items]
Number of Warrants	9,371,002
Weighted Average Exercise Price	$ 2.31
2016
Class Of Warrant Or Right [Line Items]
Year of Expiration	2016
Number of Warrants	579,712
Weighted Average Exercise Price	$ 9.74
2017
Class Of Warrant Or Right [Line Items]
Year of Expiration	2017
Number of Warrants	168,866
Weighted Average Exercise Price	$ 2.56
2018
Class Of Warrant Or Right [Line Items]
Year of Expiration	2018
Number of Warrants	6,742,068
Weighted Average Exercise Price	$ 1.68
2019
Class Of Warrant Or Right [Line Items]
Year of Expiration	2019
Number of Warrants	1,570,262
Weighted Average Exercise Price	$ 2.25
2020
Class Of Warrant Or Right [Line Items]
Year of Expiration	2020
Number of Warrants	310,094
Weighted Average Exercise Price	$ 2.28