Share-Based Compensation - Exercise Price (Details) (Amended and Restated 2012 Long Term Incentive Plan, USD $)	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price, lower limit (in dollars per share)	$ 6.03
Exercise price, upper limit (in dollars per share)	$ 37.02
Number of options outstanding	2,579,324
Options outstanding, weighted-average remaining contractual life	8 years 11 months 5 days	9 years 2 months 1 day
Options outstanding, weighted average exercise price (in dollars per share)	$ 12.95
Number of shares exercisable	747,871
Options exercisable, weighted average exercise price (in dollars per share)	$ 6.48
$6.03 - $6.03
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price, lower limit (in dollars per share)	$ 6.0300
Exercise price, upper limit (in dollars per share)	$ 6.0300
Number of options outstanding	453,375
Options outstanding, weighted-average remaining contractual life	8 years 6 months 29 days
Options outstanding, weighted average exercise price (in dollars per share)	$ 6.03
Number of shares exercisable	159,843
Options exercisable, weighted average exercise price (in dollars per share)	$ 6.03
$6.41 - $6.41
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price, lower limit (in dollars per share)	$ 6.4100
Exercise price, upper limit (in dollars per share)	$ 6.4100
Number of options outstanding	808,949
Options outstanding, weighted-average remaining contractual life	8 years 6 months 29 days
Options outstanding, weighted average exercise price (in dollars per share)	$ 6.41
Number of shares exercisable	391,208
Options exercisable, weighted average exercise price (in dollars per share)	$ 6.41
$6.65 - $6.65
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price, lower limit (in dollars per share)	$ 6.6500
Exercise price, upper limit (in dollars per share)	$ 6.6500
Number of options outstanding	50,000
Options outstanding, weighted-average remaining contractual life	8 years 8 months 19 days
Options outstanding, weighted average exercise price (in dollars per share)	$ 6.65
Number of shares exercisable	50,000
Options exercisable, weighted average exercise price (in dollars per share)	$ 6.65
$6.73 - $6.73
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price, lower limit (in dollars per share)	$ 6.7300
Exercise price, upper limit (in dollars per share)	$ 6.7300
Number of options outstanding	366,000
Options outstanding, weighted-average remaining contractual life	8 years 9 months
Options outstanding, weighted average exercise price (in dollars per share)	$ 6.73
Number of shares exercisable	126,603
Options exercisable, weighted average exercise price (in dollars per share)	$ 6.73
$8.21 - $20.53
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price, lower limit (in dollars per share)	$ 8.2100
Exercise price, upper limit (in dollars per share)	$ 20.53
Number of options outstanding	232,000
Options outstanding, weighted-average remaining contractual life	9 years 1 month 13 days
Options outstanding, weighted average exercise price (in dollars per share)	$ 14.94
Number of shares exercisable	20,217
Options exercisable, weighted average exercise price (in dollars per share)	$ 9.55
$22.14 - $22.14
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price, lower limit (in dollars per share)	$ 22.14
Exercise price, upper limit (in dollars per share)	$ 22.14
Number of options outstanding	100,000
Options outstanding, weighted-average remaining contractual life	9 years 10 months 2 days
Options outstanding, weighted average exercise price (in dollars per share)	$ 22.14
Number of shares exercisable	0
Options exercisable, weighted average exercise price (in dollars per share)	$ 0.00
$24.26 - $24.26
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price, lower limit (in dollars per share)	$ 24.26
Exercise price, upper limit (in dollars per share)	$ 24.26
Number of options outstanding	30,000
Options outstanding, weighted-average remaining contractual life	9 years 4 months 2 days
Options outstanding, weighted average exercise price (in dollars per share)	$ 24.26
Number of shares exercisable	0
Options exercisable, weighted average exercise price (in dollars per share)	$ 0.00
$29.52 - $29.52
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price, lower limit (in dollars per share)	$ 29.52
Exercise price, upper limit (in dollars per share)	$ 29.52
Number of options outstanding	25,000
Options outstanding, weighted-average remaining contractual life	9 years 7 months 2 days
Options outstanding, weighted average exercise price (in dollars per share)	$ 29.52
Number of shares exercisable	0
Options exercisable, weighted average exercise price (in dollars per share)	$ 0.00
$29.81 - $29.81
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price, lower limit (in dollars per share)	$ 29.81
Exercise price, upper limit (in dollars per share)	$ 29.81
Number of options outstanding	484,000
Options outstanding, weighted-average remaining contractual life	9 years 7 months 6 days
Options outstanding, weighted average exercise price (in dollars per share)	$ 29.81
Number of shares exercisable	0
Options exercisable, weighted average exercise price (in dollars per share)	$ 0.00
$37.02 - $37.02
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price, lower limit (in dollars per share)	$ 37.02
Exercise price, upper limit (in dollars per share)	$ 37.02
Number of options outstanding	30,000
Options outstanding, weighted-average remaining contractual life	9 years 9 months
Options outstanding, weighted average exercise price (in dollars per share)	$ 37.02
Number of shares exercisable	0
Options exercisable, weighted average exercise price (in dollars per share)	$ 0.00