Warrants - Activity (Details) - $ / shares	6 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Shares
Outstanding at beginning of period (in shares)	913,441
Exercised (in shares)	(337,228)
Expired (in shares)	(12,215)
Outstanding at end of period (in shares)	563,998
Exercisable at end of period (in shares)	563,998
Equity classified as warrants	21,920	21,920
Weighted Average Exercise Price
Outstanding at beginning of period (in dollars per share)	$ 7.45
Exercised (in dollars per shares)	0.05
Expired ( in dollars per share)	22.50
Outstanding at end of period (in dollars per share)	11.61
Exercisable at end of period (in dollars per share)	11.61
Range of Exercise Prices
Exercised (in dollars per share)	0.05
Expired (in dollars per share)	22.50
Minimum
Range of Exercise Prices
Outstanding at beginning of period (in dollars per share)	0.05
Outstanding at end of period (in dollars per share)	6.10
Exercisable (in dollars per share)	6.10
Maximum
Range of Exercise Prices
Outstanding at beginning of period (in dollars per share)	22.50
Outstanding at end of period (in dollars per share)	21.00
Exercisable (in dollars per share)	$ 21.00