STOCK-BASED COMPENSATION (Stock Option Award Activity) (Details) - $ / shares	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Weighted Average Remaining Life Exercisable
Total shares excluded from net loss per share attributable to common stockholders	7,087,528	6,101,177
Common stock options
Number of Options outstanding
Outstanding at the beginning of the year (in shares)	1,255,280
Granted (in shares)	40,000	37,500
Exercised (in shares)	0
Forfeited (in shares)	(1,252)
Outstanding at the end of the reporting period (in shares)	1,294,028		1,255,280
Number of Options Exercisable
Exercisable at the beginning of the year (in shares)	843,019
Vested (in shares)	(42,436)
Forfeited (in shares)	(1,252)
Exercisable at the end of the reporting period (in shares)	884,203		843,019
Weighted Average Exercise Price Outstanding
Outstanding at the beginning of period (in dollars per share)	$ 4.82
Granted (in dollars per share)	2.23
Exercised (in dollars per share)	0.00
Forfeited (in dollars per share)	4.62
Outstanding at the end of the reporting period (in dollars per share)	4.74		$ 4.82
Weighted Average Exercise Price Exercisable
Exercisable at the beginning of the reporting period (in dollars per share)	5.02
Vested exercisable (in dollars per share)	4.37
Forfeited (in dollars per share)	4.62
Exercisable at the end of the reporting period (in dollars per share)	4.99		5.02
Weighted Average Grant Date Fair Value Outstanding
Outstanding at the beginning of the reporting period (in dollars per share)	3.03
Granted (in dollars per share)	1.51
Exercised (in dollars per share)	0.00
Forfeited (in dollars per share)	2.79
Outstanding at the end of the reporting period (in dollars per share)	2.98		3.03
Weighted Average Grant Date Fair Value Exercisable
Exercisable at the beginning of the reporting period (in dollars per share)	3.13
Vested options exercisable (in dollars per share)	2.74
Exercised options exercisable (in dollars per share)	0.00
Forfeited options exercisable (in dollars per share)	2.79
Exercisable at the end of the reporting period (in dollars per share)	$ 3.11		$ 3.13
Weighted Average Remaining Life In Years Outstanding
Outstanding Weighted Average Remaining Life (in years)	7 years 6 months 26 days		7 years 9 months
Granted (in years)	9 years 10 months 2 days
Weighted Average Remaining Life Exercisable
Exercisable, Weighted Average Remaining Life	7 years 15 days		7 years 2 months 23 days
Granted (in years)	8 years 4 days