STOCK-BASED COMPENSATION (Tables)

9 Months Ended

Sep. 30, 2013

STOCK-BASED COMPENSATION

Schedule of allocation of stock-based compensation expense included in the consolidated statements of operations

	Three Months Ended September 30,				Nine Months Ended September 30,
(In thousands)	2013		2012		2013		2012
Research and development	$	4,191	$	3,259	$	12,496	$	10,329
Selling, general and administrative	2,255		2,571		7,208		7,715
Total stock-based compensation expense	$	6,446	$	5,830	$	19,704	$	18,044

Schedule of weighted-average assumptions used to estimate the fair value of stock options granted

	Three Months Ended September 30,						Nine Months Ended September 30,
	2013			2012			2013			2012
Employee stock options
Risk-free interest rate	1.68%-2.02		%	0.83%-0.86		%	0.76%-2.02		%	0.74%-1.17		%
Expected term (in years)	6			6			5-6			5-6
Volatility	60		%	57		%	58%-60		%	55%-60		%
Dividend yield	—		%	—		%	—		%	—		%
Weighted-average estimated fair value of stock options granted	$	21.63		$	14.31		$	18.11		$	11.41