STOCK OPTIONS - Summary of Nonvested Stock Options (Details) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Number of options
Number of Options Non-vested at beginning of period (in shares)	1,436,429
Number of Options Non-vested, Granted (in shares)	1,379,500	225,000	1,728,000
Number of Options Non-vested, Vested (in shares)	(1,119,000)
Number of Options Non-vested, Forfeited (in shares)	(212,000)
Number of Options Non-vested at end of period (in shares)	1,484,929	1,436,429
Weighted average grant date fair value
Weighted average grant date fair value, Non-vested Options at beginning of period (in dollars per share)	$ 1.68
Weighted average grant date fair value, Non-vested Options, Granted (in dollars per share)	4.57	$ 2.40	$ 1.82
Weighted average grant date fair value, Non-vested Options, Vested (in dollars per share)	1.90
Weighted average grant date fair value, Non-vested Options, Forfeited (in dollars per share)	2.31
Weighted average grant date fair value, Non-vested Options at end of period (in dollars per share)	$ 4.11	$ 1.68