STOCK AWARD PLAN AND STOCK-BASED COMPENSATION - Schedule of Stock-Based Compensation Expense Included in the Company's Consolidated Statements of Operations (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock based compensation expense	$ 1,114,526	$ 2,056,035	$ 4,014,650	$ 7,739,704
Research and Development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock based compensation expense	541,332	813,443	1,826,881	2,189,595
General and Administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock based compensation expense	$ 573,194	$ 1,242,592	$ 2,187,769	$ 5,550,109