Stock-based Compensation Expense (Details 2) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award
Exercise price range, options outstanding (in shares)	12,682
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	7 years 3 months 11 days
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 65.17
Exercise price range, options exercisable (in shares)	5,410
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 47.36
$17.16 to $20.00
Share-based Compensation Arrangement by Share-based Payment Award
Exercise price, low end of range (usd per share)	$ 17.16
Exercise price, high end of range (usd per share)	$ 20.00
Exercise price range, options outstanding (in shares)	165
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	2 years 6 months 4 days
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 18.69
Exercise price range, options exercisable (in shares)	165
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 18.69
$20.01 to $40.00
Share-based Compensation Arrangement by Share-based Payment Award
Exercise price, low end of range (usd per share)	$ 20.01
Exercise price, high end of range (usd per share)	$ 40
Exercise price range, options outstanding (in shares)	3,207
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	4 years 2 months 27 days
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 34.97
Exercise price range, options exercisable (in shares)	2,711
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 34.73
$40.01 to $60.00
Share-based Compensation Arrangement by Share-based Payment Award
Exercise price, low end of range (usd per share)	$ 40.01
Exercise price, high end of range (usd per share)	$ 60
Exercise price range, options outstanding (in shares)	3,339
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	7 years 3 months 29 days
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 48.55
Exercise price range, options exercisable (in shares)	1,499
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 50.27
$60.01 to $80.00
Share-based Compensation Arrangement by Share-based Payment Award
Exercise price, low end of range (usd per share)	$ 60.01
Exercise price, high end of range (usd per share)	$ 80
Exercise price range, options outstanding (in shares)	1,837
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	8 years 7 months 2 days
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 76.07
Exercise price range, options exercisable (in shares)	492
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 74.88
$80.01 to $100.00
Share-based Compensation Arrangement by Share-based Payment Award
Exercise price, low end of range (usd per share)	$ 80.01
Exercise price, high end of range (usd per share)	$ 100
Exercise price range, options outstanding (in shares)	2,232
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	8 years 8 months 12 days
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 90.29
Exercise price range, options exercisable (in shares)	542
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 86.07
$100.01 to $120.00
Share-based Compensation Arrangement by Share-based Payment Award
Exercise price, low end of range (usd per share)	$ 100
Exercise price, high end of range (usd per share)	$ 120
Exercise price range, options outstanding (in shares)	1,898
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	9 years 10 months 2 days
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 109.23
Exercise price range, options exercisable (in shares)	1
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 110.59
$120.01 to $125.63
Share-based Compensation Arrangement by Share-based Payment Award
Exercise price, low end of range (usd per share)	$ 120
Exercise price, high end of range (usd per share)	$ 126
Exercise price range, options outstanding (in shares)	4
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	9 years 9 months 26 days
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 125.63
Exercise price range, options exercisable (in shares)	0
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 0.00