Warrants - Activity (Details) - $ / shares	3 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Shares
Outstanding at beginning of period (in shares)	4,567,207
Exercised (in shares)	(953,592)
Outstanding at end of period (in shares)	3,613,615
Exercisable at end of period (in shares)	1,986,222
Equity classified as warrants	170,676	170,676
Weighted Average Exercise Price
Outstanding at beginning of period (in dollars per share)	$ 1.49
Exercised (in dollars per shares)	0.01
Outstanding at end of period (in dollars per share)	1.89
Exercisable at end of period (in dollars per share)	2.04
Range of Exercise Prices
Exercised (in dollars per share)	0.01
Minimum
Range of Exercise Prices
Outstanding at beginning of period (in dollars per share)	0.01
Outstanding at end of period (in dollars per share)	0.01
Exercisable (in dollars per share)	0.01
Maximum
Range of Exercise Prices
Outstanding at beginning of period (in dollars per share)	4.50
Outstanding at end of period (in dollars per share)	4.50
Exercisable (in dollars per share)	$ 4.50