SHARE-BASED COMPENSATION (Details 2) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2017 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Balance, beginning of year (in shares) | shares	2,813,342
Granted (in shares) | shares	970,226
Exercise of options (in shares) | shares	(45,573)
Canceled (in shares) | shares	(415,908)
Expired (in shares) | shares	(17,906)
Balance, end of year (in shares) | shares	3,304,181
Options exercisable, end of year (in shares) | shares	1,843,808
Vested and unvested expected to vest options outstanding (in shares) | shares	3,304,181
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Balance, beginning of year (in dollars per share) | $ / shares	$ 16.57
Granted (in dollars per share) | $ / shares	5.36
Exercised (in dollars per share) | $ / shares	8.74
Canceled (in dollars per share) | $ / shares	14.47
Expired (in dollars per share) | $ / shares	12.50
Balance, end of year (in dollars per share) | $ / shares	13.67
Options exercisable, end of year (in dollars per share) | $ / shares	16.28
Vested and unvested expected to vest options outstanding, Weighted-Average Exercise Price (in dollars per share) | $ / shares	$ 13.67
Options outstanding, Weighted-Average Remaining Contractual Term (years)	7 years 2 months
Options exercisable, Weighted-Average Remaining Contractual Term (years)	6 years 1 month
Options vested and expected to vest, Weighted-Average Remaining Contractual Term (years)	7 years 2 months
Options outstanding, Aggregate Intrinsic Value | $	$ 21.0
Options exercisable, Aggregate Intrinsic Value | $	7.3
Options vested and expected to vest, Aggregate Intrinsic Value | $	$ 21.0