NET INCOME (LOSS) PER SHARE (Details) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Net income (loss) per share.
Equivalent shares of options excluded from computation of diluted net income (loss) per share because anti-dilutive effect	13,724,000	10,261,000	13,435,000	10,520,000
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