Summary of Common Stock Warrants - A, B, C, D (Details)	Series A	Series B	Series C	Series D	A,B,C,D Total Warrants
Outstanding at Dec. 31, 2013	1,188,909	5,332,981	128,180	15,312,627	21,962,697
Issued	0	0	0	0	0
Exercised	(1,188,909)	(5,328,481)	(128,180)	(807,861)	(7,453,431)
Outstanding at Dec. 31, 2014	0	4,500		14,504,766	14,509,266
Issued	0	0	0	0	0
Exercised	0	0	0	(226,740)	(226,740)
Outstanding at Mar. 31, 2015	0	4,500	0	14,278,026	14,282,526

Number of share options (or share units) exercised during the current period.