SHARE-BASED COMPENSATION (Tables)

9 Months Ended

Sep. 30, 2017

Disclosure of Compensation Related Costs, Share-based 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,
	2017		2016		2017		2016
Sales, general and administrative	$	6.5	$	3.5	$	18.2	$	11.8
Research and development		3.7		2.8	$	10.9	$	8.7
Total share-based compensation expense	$	10.2	$	6.3	$	29.1	$	20.5

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,
	2017			2016			2017			2016
Risk-free interest rate		1.8	%		1.1	%		2.0	%		1.4	%
Expected volatility of common stock		59.6	%		59.3	%		58.2	%		60.0	%
Dividend yield		0.0	%		0.0	%		0.0	%		0.0	%
Expected option term		5 years			5 years			5.7 years			5.6 years