EMPLOYEE STOCK BENEFIT PLANS (Tables)

9 Months Ended

Sep. 30, 2014

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of stock-based compensation expense

Stock-based compensation expense recorded in the condensed consolidated statements of comprehensive income for the three and nine months ended September 30, 2014 and 2013, is as follows:

	Three Months Ended September 30,						Nine Months Ended September 30,
	2014			2013			2014			2013
	(in thousands)
Stock-based compensation expense allocation:
Cost of product revenues	$	341		$	120		$	610		$	374
Research and development expense	3,116			2,816			9,835			8,583
Selling, general and administrative expense	5,947			5,029			17,927			15,147
Total stock-based compensation expense	9,404			7,965			28,372			24,104
Income tax effect	(3,069		)	(2,993		)	(9,619		)	(9,058		)
After-tax effect of stock-based compensation expense	$	6,335		$	4,972		$	18,753		$	15,046

Schedule of option activity

A summary of option activity for the nine months ended September 30, 2014, is as follows: 

	Number of shares			Weighted Average Exercise Price
Outstanding as of December 31, 2013	7,478,169			$	31.61
Granted	759,820			$	72.36
Exercised	(1,106,320		)	$	25.47
Canceled	(196,027		)	$	42.41
Outstanding as of September 30, 2014	6,935,642			$	36.75
Vested and exercisable as of September 30, 2014	4,673,781			$	29.70
Weighted average grant-date fair value of options granted during the period	$	19.33

Schedule of RSU activity, including PRSUs

A summary of RSU activity, including PRSUs, for the nine months ended September 30, 2014, is as follows:

	Number of Shares		Weighted Average Grant Date Fair Value
Nonvested as of December 31, 2013	882,272		$	40.97
Granted	766,260		$	70.37
Vested	(291,563	)	$	38.00
Forfeited	(80,569	)	$	52.53
Nonvested as of September 30, 2014	1,276,400		$	58.57