Business (Details) (USD $)	0 Months Ended	3 Months Ended		39 Months Ended	0 Months Ended	1 Months Ended
	Jan. 14, 2014	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2015	Jul. 23, 2014	Jul. 31, 2014	Dec. 31, 2014	Dec. 31, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Net cash used for operating activities		$ 5,509,000	$ 2,729,000	$ 25,209,000
Schedule of Capitalization, Equity [Line Items]
Cash and cash equivalents		42,712,000	5,885,000	42,712,000			48,555,000	8,629,000
Reverse stock split ratio	0.02
Underwriting Agreement [Member]
Schedule of Capitalization, Equity [Line Items]
Proceeds from the underwriting agreement, including additional shares sold, net of cost					$ 53,100,000	$ 53,100,000