Stockholders Equity (SBC) (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Stock-based compensation
Stock-based compensation expense	$ 563,115	$ 1,293,013	$ 1,492,360	$ 2,913,844
Research and development
Stock-based compensation
Stock-based compensation expense	27,588	347,281	64,639	816,959
General and administrative
Stock-based compensation
Stock-based compensation expense	535,527	945,732	1,427,721	2,096,885
Options awards
Stock-based compensation
Stock-based compensation expense	$ 618,896	1,233,950	$ 1,659,704	2,561,157
Additional disclosures
Contractual life			7 years
Shares
Outstanding at the beginning of the period (in shares)			4,020,783
Forfeited (in shares)			(986,145)
Outstanding at the end of the period (in shares)	3,034,638		3,034,638		4,020,783
Vested and expected to vest (in shares)	3,027,715		3,027,715
Exercisable (in shares)	2,628,632		2,628,632
Weighted-Average Exercise Price Per Share
Outstanding at beginning of the period (in dollars per share)			$ 5.48
Forfeited (in dollars per share)			5.45
Outstanding at the end of the period (in dollars per share)	$ 5.49		5.49		$ 5.48
Vested and expected to vest at the end of the period (in dollars per share)	5.49		5.49
Exercisable at the end of the period (in dollars per share)	$ 5.48		$ 5.48
Weighted-Average Contractual Life (In Years)
Outstanding at the end of the period			7 years 2 months 12 days		7 years 9 months 18 days
Vested and expected to vest at the end of the period			7 years 2 months 12 days
Exercisable at the end of the period			7 years
Restricted stock awards
Stock-based compensation
Stock-based compensation expense		$ 59,063		$ 352,687