SHAREHOLDERS' EQUITY - OPTIONS AND RESTRICTED SHARE UNITS ROLL FORWARD (Details) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017	Dec. 12, 2017
2009 Plan | Stock options, all inclusive recipients
Aggregate intrinsic value
Shares available for future grant (in shares)			805,593
Amended 2009 Stock Plan | Stock options, employees and directors
Number of options
Options outstanding at beginning of period (in shares)	2,057,862
Options exercised (in shares)	(46,220)
Options forfeited (in shares)	(136,820)
Options outstanding at end of period (in shares)	1,874,822	2,057,862
Options vested at end of period (in shares)	1,267,854
Weighted average exercise price
Options outstanding at beginning of period (in dollars per share)	$ 4.03
Options exercised (in dollars per share)	3.25
Options forfeited (in dollars per share)	3.97
Options outstanding at end of period (in dollars per share)	4.06	$ 4.03
Options vested at end of period (in dollars per share)	$ 4.20
Weighted average remaining contractual life
Weighted average remaining contractual life, Outstanding (in years)	5 years 8 months 19 days	6 years 1 month 13 days
Weighted average remaining contractual life, Vested (in years)	4 years 1 month 17 days
Aggregate intrinsic value
Aggregate intrinsic value, Outstanding	$ 1,459,000	$ 384,000
Aggregate intrinsic value, Vested	$ 904,000
Amended and Restated 2009 Stock Incentive Plan
Aggregate intrinsic value
Shares available for future grant (in shares)	1,408,032
Amended and Restated 2009 Stock Incentive Plan | Restricted share units, employees and directors
Number of restricted share units
Unvested at beginning of period (in shares)	247,095
RSUs vested	$ (113,658)
RSUs forfeited	(19,787)
Unvested at end of period (in shares)	113,650	247,095
Weighted average grant date fair value
Unvested at beginning of period (in dollars per share)	$ 3.32
RSUs vested (in dollars per share)	3.34
RSUs forfeited (in dollars per share)	3.16
Unvested at end of period (in dollars per share)	$ 3.34	$ 3.32
Aggregate intrinsic value
Aggregate intrinsic value, Unvested at beginning of period	$ 914,000
Aggregate intrinsic value, RSU's vested	511,000
Aggregate intrinsic value, RSU's forfeited
Aggregate intrinsic value, Unvested at end of the period	$ 511,000	$ 914,000