Loss Per Share (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Number of common stock warrant and common stock options exercised	3,556,688		5,262,094
Number of common stock issued for stock warrant and stock options exercised	3,556,602		4,866,852
Shares surrendered in lieu of cash payment	86		395,242
Common stock investments, available for sale
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential common shares	29,874,112	35,157,966	29,231,538	31,659,650