SHARE-BASED COMPENSATION (Tables)

9 Months Ended

Sep. 30, 2013

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Compensation Expenses Related to Share Based Compensation

The compensation expense related to the Company’s share-based compensation arrangements has been included in the condensed consolidated statements of comprehensive loss as follows (in millions):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2013		2012		2013		2012
General and administrative	$	0.9	$	0.7	$	2.6	$	2.1
Research and development		0.8		0.7	$	2.5	$	2.1
Total share-based compensation expense	$	1.7	$	1.4	$	5.1	$	4.2

Weighted-Average Assumptions for Stock Option Grants using Black-Scholes Option-Pricing Model

The estimated fair value of each stock option granted was determined on the date of grant using the Black-Scholes option-pricing model with the following weighted-average assumptions for the stock option grants:

	Three Months Ended September 30,		Nine Months Ended September 30,
	2013	2012	2013	2012
Risk-free interest rate	—	0.9%	1.4%	1.3%
Expected volatility of common stock	—	72.1%	75.8%	79.4%
Dividend yield	—	0.0%	0.0%	0.0%
Expected option term	—	6 years	7.3 years	6.8 years