SHARE-BASED COMPENSATION (Tables)

3 Months Ended

Mar. 31, 2014

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 March 31,
	2014		2013
General and administrative	$	1.2	$	0.8
Research and development		1.2		0.9
Total share-based compensation expense	$	2.4	$	1.7

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 March 31,
	2014	2013
Risk-free interest rate	2.3%	1.3%
Expected volatility of common stock	71.3%	75.6%
Dividend yield	0.0%	0.0%
Expected option term	7.1 years	7.3 years