Equity-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2014

Equity-Based Compensation

Schedule of equity-based compensation expense

Equity-based compensation expense for 2014, 2013 and 2012 consisted of the following (in thousands):

	Years Ended December 31,
	2014		2013		2012
Cost of product sales	$	122	$	121	$	225
Research and development		1,596		2,149		1,994
Selling, general and administrative		6,907		5,734		4,805
Total equity-based compensation expense	$	8,625	$	8,004	$	7,024

Summary of weighted average assumptions used for valuing option awards granted

	Years Ended December 31,
	2014				2013				2012
	Employees		Non-Employee Directors		Employees		Non-Employee Directors		Employees		Non-Employee Directors
Risk free interest rate (%)		1.56		1.28		0.95		0.85		0.66		0.68
Expected volatility (%)		47		46		59		46		57		56
Expected option term (years)		5.00		4.00		5.00		4.00		4.66		4.00
Dividend yield		none		none		none		none		none		none

Summary of details regarding stock options granted under equity incentive plans

	December 31, 2014
	Options			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term		Aggregate Intrinsic Value ($ in millions)
Outstanding at beginning of year		2,819,676		$	21.31
Granted		1,391,776			25.75
Exercised		(494,576	)		19.43
Expired and/or forfeited		(720,493	)		25.81
Outstanding at end of year		2,996,383		$	22.60		7.7	$	60,546
Outstanding at end of year—vested and unvested expected to vest		2,688,944		$	22.60		7.6	$	54,410
Exercisable at end of year		946,787		$	22.47		6.0	$	60,459

Summary of details regarding restricted stock units granted under equity incentive plans

	December 31, 2014
	Unvested Restricted Stock Units			Weighted Average Grant Date Fair Value
Outstanding at beginning of year		465,394		$	17.28
Granted		356,626			22.88
Vested		(151,518	)		17.71
Forfeited		(129,276	)		18.25
Outstanding at end of year		541,226		$	20.62
Outstanding at end of year and expected to vest		465,686		$	20.59