SHARE - BASED COMPENSATION - Option Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Underlying Shares
Outstanding at beginning of period (in shares)	3,065
Granted (in shares)	1,489
Exercised (in shares)	(41)
Forfeited or expired (in shares)	(488)
Outstanding at end of period (in shares)	4,025	3,065
Exercisable at end of period (in shares)	1,989
Weighted-Average Exercise Price
Outstanding at beginning of period (in dollars per share)	$ 5.85
Granted (in dollars per share)	1.77
Exercised (in dollars per share)	2.63
Forfeited or expired (in dollars per share)	9.79
Outstanding at end of period (in dollars per share)	3.89	$ 5.85
Exercisable at end of period (in dollars per share)	$ 5.26
Weighted Average Remaining Contractual Term (years)
Outstanding	6 years 7 months 6 days	4 years 9 months 18 days
Exercisable	2 years 4 months 24 days
Additional Disclosures
Weighted average grant date fair value of options granted (in dollars per share)	$ 1.18
Stock options
Additional Disclosures
Unrecognized stock-based compensation expense (in dollars)	$ 5.3
Weighted-average amortization period	2 years 2 months 12 days