QUARTERLY FINANCIAL INFORMATION (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Table Text Block Supplement [Abstract]
License revenue	$ 38,095	$ 38,096	$ 38,095	$ 38,095	$ 38,095	$ 38,096	$ 38,095	$ 38,095
Total costs and expenses	31,072,826	31,623,323	28,463,466	27,704,517	24,066,153	24,963,567	16,061,538	14,030,251	$ 118,864,132	$ 79,121,509	$ 63,332,397
Net loss	$ (30,859,767)	$ (31,535,652)	$ (28,353,084)	$ (27,727,509)	$ (23,674,143)	$ (24,831,027)	$ (15,899,062)	$ (13,848,662)
Basic and diluted net loss per common share	$ (0.46)	$ (0.48)	$ (0.45)	$ (0.52)	$ (0.48)	$ (0.50)	$ (0.33)	$ (0.28)	$ (1.91)	$ (1.60)	$ (1.38)