Share-Based Compensation (Tables)
 6 Months Ended
Jun. 30, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]  
Expenses Associated with Share-Based Compensation Plans

The following table presents compensation expense associated with the Company’s share-based compensation plans:

 

 

Three Months Ended
June 30,

 

  

Six Months Ended
June 30,

 

(in thousands)

 

2016

 

  

2015

 

  

2016

 

  

2015

 

Expense:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

RSUs

$

5,384

  

  

$

4,117

  

  

$

20,365

  

  

$

14,219

  

Stock options

 

68

 

 

 

68

 

 

 

135

 

 

 

135

 

Employee stock purchase plan

 

658

 

  

 

520

  

  

 

1,468

  

  

 

1,209

  

 

$

6,110

  

  

$

4,705

  

  

$

21,968

  

  

$

15,563

  

 
Summary of RSU Activity

The following table summarizes RSU activity for the six months ended June 30, 2016:

 

(in thousands, except weighted-average grant-date fair value)

 

Shares

 

 

Weighted-average
grant-date

fair value

 

RSUs unvested at December 31, 2015

 

1,354

 

 

$

29.20

 

Granted during 2016

 

925

 

 

$

36.79

 

Vested during 2016

 

(703

)

 

$

30.78

 

Forfeited during 2016

 

(12

)

 

$

30.57

 

RSUs unvested at June 30, 2016

 

1,564

 

 

$

32.97

 

 
Summary of Stock Option Activity

The following table summarizes stock option activity for the six months ended June 30, 2016:

 

(in thousands, except weighted-average exercise price and contractual term)

 

Number

outstanding

 

 

Weighted-

average

exercise price

  

  

Weighted-

average

remaining

contractual term

   

  

Aggregate

intrinsic

value

 

Balance at December 31, 2015

 

132

 

 

$

27.66

 

 

 

 

 

 

 

 

 

Exercised during 2016

 

—

 

 

$

—

 

 

 

 

 

 

 

 

 

Balance at June 30, 2016

 

132

 

 

$

27.66

 

 

 

7.5 years

 

 

$

1,662

 

Vested and expected to vest at June 30, 2016

 

132

 

 

$

27.66

 

 

 

7.5 years

 

 

$

1,662

 

Exercisable at June 30, 2016

 

66

 

 

$

27.66

 

 

 

7.5 years

 

 

$

831