STOCKHOLDERS' EQUITY - Warrant activity (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Stockholders' Equity [Abstract]
Warrants, Outstanding at Beginning Balance	0	0	913,379
Warrants, Issued	147,058	0	0
Warrants, Exercised	0	0	887,585
Warrants, Expired	0	0	25,794
Warrants, Outstanding at Ending Balance	147,058	0	0
Weighted - average exercise price of Warrants, Outstanding at Beginning Balance	$ 0	$ 0	$ 2.41
Weighted - average exercise price of Warrants, Issued	4.08	0	0
Weighted - average exercise price of Warrants, Exercised	0	0	2.41
Weighted - average exercise price of Warrants, Expired	0	0	0
Weighted - average exercise price of Warrants, Outstanding at Ending Balance	$ 4.08	$ 0	$ 0
Aggregate Intrinsic Value of Warrants, Outstanding at Beginning Balance	$ 0	$ 0	$ 1,961,403
Aggregate Intrinsic Value of Warrants, Outstanding at Ending Balance	$ 1,032,347	$ 0	$ 0