NET INCOME PER SHARE NET INCOME PER SHARE (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Jun. 15, 2015
Antidilutive Securities Excluded from Computation of Net Loss Per Share [Line Items]
Anti-dilutive potential common shares (in thousands of shares)	2,262	4,759	1,254	5,985
Convertible Notes Payable, Noncurrent	$ 125,000		$ 125,000		$ 125,000
Debt Instrument, Convertible, Terms of Conversion Feature	The Notes are convertible into cash, shares of the Company’s common stock or a combination of cash and shares of common stock, at the Company’s election, based on an initial conversion rate, subject to adjustment.		The Notes are convertible into cash, shares of the Company’s common stock or a combination of cash and shares of common stock, at the Company’s election, based on an initial conversion rate, subject to adjustment, of 45.5840 shares per $1,000 principal amount of Notes, which is equal to an initial conversion price of $21.94 per share. Prior to December 15, 2019, the Notes are convertible only in the following circumstances: (1) during any calendar quarter commencing after September 30, 2015, if the last reported sale price of the Company’s common stock is greater than or equal to 130% of the applicable conversion price for at least 20 trading days during a period of 30 consecutive trading days ending on the last trading day of the preceding calendar quarter; (2) during the five business day period after any five consecutive trading day period (the “Measurement Period”) in which the trading price per $1,000 principal amount of notes for each trading day in the Measurement Period was less than 98% of the product of the last reported sale price of the Company’s common stock and the conversion rate on such trading day; or (3) upon the occurrence of specified corporate transactions.
Options
Antidilutive Securities Excluded from Computation of Net Loss Per Share [Line Items]
Anti-dilutive potential common shares (in thousands of shares)	1,847	4,705		5,902
Non-vested restricted stock units
Antidilutive Securities Excluded from Computation of Net Loss Per Share [Line Items]
Anti-dilutive potential common shares (in thousands of shares)	415	54	231	83
Options | Options
Antidilutive Securities Excluded from Computation of Net Loss Per Share [Line Items]
Anti-dilutive potential common shares (in thousands of shares)			1,023