NET LOSS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Earnings Per Share [Abstract]
Net loss attributable to common stock	$ (9,644)	$ (10,442)
Weighted average shares outstanding, basic and diluted (in shares)	51,774	51,336
Net loss per share, basic and diluted (in dollars per share)	$ (0.19)	$ (0.20)
Anti-dilutive securities excluded from diluted net loss per share calculation for stock-based compensation plans (in shares)	7,598	7,296