NET INCOME (LOSS) PER SHARE (Details) - $ / shares	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Net income (loss) per share.
Equivalent shares of options excluded from computation of diluted net income (loss) per share because anti-dilutive effect	10,354,000	7,587,000
Convertible Senior Notes Due 2020
Net income (loss) per share.
Net shares issued	0
Minimum stock price to trigger conversion of debt (in dollars per share)	$ 20
Convertible Senior Notes Due 2020 | Convertible Common Stock
Net income (loss) per share.
Dilutive Securities impact on diluted net income (in dollars per share)	$ 0