INCOME TAXES - Effective Income Tax Rate Reconciliation (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Expense (Benefit), Continuing Operations, Income Tax Reconciliation [Abstract]
Income tax at the federal statutory rate	$ (22.7)	$ (4.0)	$ 8.7
Change in valuation allowance related to deferred tax assets	6.1	5.3	6.2
Change in uncertain tax positions, including interest	0.9	(1.5)	0.3
State income tax, net of federal income tax effect	(1.9)	(4.1)	2.1
Tax effect resulting from foreign activities and foreign dividends	(1.9)	0.5	(3.3)
Non-deductible expenses	2.6	0.9	2.3
Research credits	(2.5)	(1.8)	(1.7)
Other, net	0	1.6	0.7
(Benefit) provision for income taxes	$ (19.4)	$ (3.1)	$ 15.3
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Income tax at the federal statutory rate (percent)	35.00%	35.00%	35.00%
Change in valuation allowance related to deferred tax assets (percent)	(9.40%)	(46.50%)	24.90%
Change in uncertain tax positions, including interest (percent)	(1.40%)	13.20%	1.10%
State income tax, net of federal income tax effect (percent)	2.90%	35.90%	8.40%
Tax effect resulting from foreign activities and foreign dividends (percent)	2.90%	(4.30%)	(13.40%)
Non-deductible expenses (percent)	(4.00%)	(7.90%)	9.40%
Research credits (percent)	3.80%	15.80%	(6.70%)
Other, net (percent)	0.00%	(14.00%)	3.00%
Effective tax rate (percent)	29.80%	27.20%	61.70%