INCOME TAXES (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets (liabilities):
Net operating loss carryforwards	$ 83,655,879	$ 95,329,928
Research and development credit	10,490,793	7,326,715
Noncash compensation	4,933,807	12,915,672
Other	632,274	599,514
Deferred tax asset, excluding valuation allowance	99,712,753	116,171,829
Less valuation allowance	(99,712,753)	(116,171,829)	$ (86,358,850)
Net deferred tax assets	$ 0	$ 0