Fair Value (Details 3)	6 Months Ended	0 Months Ended	6 Months Ended	12 Months Ended	0 Months Ended	6 Months Ended	12 Months Ended	0 Months Ended	6 Months Ended
	Jun. 30, 2014 Warrant	May 31, 2011 Common stock warrants issued on May 31, 2011	Jun. 30, 2014 Common stock warrants issued on May 31, 2011	Dec. 31, 2013 Common stock warrants issued on May 31, 2011	Feb. 20, 2013 Common stock warrants issued on February 20, 2013	Jun. 30, 2014 Common stock warrants issued on February 20, 2013	Dec. 31, 2013 Common stock warrants issued on February 20, 2013	Feb. 15, 2014 Common stock warrants issued on January 15, 2014	Jun. 30, 2014 Common stock warrants issued on January 15, 2014
Valuation technique for assets measured and recorded at fair value
Risk-free interest rate (as a percent)		0.75%	0.45%	0.52%	0.85%	1.29%	1.14%	1.65%	1.68%
Volatility (as a percent)		94.40%	154.10%	119.30%	102.00%	123.50%	99.00%	107.60%	115.70%
Expected average term		2 years 6 months	1 year 10 months 24 days	2 years 4 months 24 days	5 years	3 years 7 months 6 days	4 years 1 month 6 days	5 years	4 years 7 months 6 days
Expected dividend yield (as a percent)	0.00%