Stock-based Compensation Expense (Details 2) (USD $) In Thousands, except Per Share data, unless otherwise specified	6 Months Ended	3 Months Ended
	Jun. 30, 2014	Jun. 30, 2014 $10.41–$20.00	Jun. 30, 2014 $20.01–$30.00	Jun. 30, 2014 $30.01–$40.00	Jun. 30, 2014 $40.01–$50.00	Jun. 30, 2014 $50.01–$60.00	Jun. 30, 2014 $60.01–$70.00	Jun. 30, 2014 $70.01–$80.00	Jun. 30, 2014 $80.01–$88.18
Share-based Compensation Arrangement by Share-based Payment Award
Exercise price, low end of range (usd per share)		$ 10.41	$ 20.01	$ 30.01	$ 40.01	$ 50.01	$ 60.01	$ 70.01	$ 80.01
Exercise price, high end of range (usd per share)		$ 20.00	$ 30.00	$ 40.00	$ 50.00	$ 60.00	$ 70.00	$ 80	$ 88.18
Exercise price range, options outstanding (in shares)	14,549	368	889	4,876	3,508	1,348	129	2,095	1,336
Exercise price range, options outstanding, weighted-average remaining contractual life (in years)	7 years 1 month 6 days	2 years 4 days	5 years 5 months 1 day	5 years 2 months 1 day	8 years 4 months 13 days	7 years 4 months 2 days	9 years 1 month 24 days	9 years 7 months 6 days	9 years 7 days
Exercise price range, options outstanding, weighted-average exercise price (in dollars per share)	$ 49.77	$ 15.59	$ 29.46	$ 36.20	$ 46.32	$ 54.11	$ 65.71	$ 76.73	$ 83.11
Exercise price range, options exercisable (in shares)	7,227	368	708	3,758	890	800	20	308	375
Exercise price range, options exercisable, weighted-average exercise price (in dollars per share)	$ 41.65	$ 15.59	$ 29.35	$ 35.73	$ 46.55	$ 54.63	$ 64.33	$ 74.18	$ 82.53