Stock-Based Compensation (Tables)
12 Months Ended
Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]  
Summary of Stock Option Activity
The following table presents a summary of stock option activity in 2014, 2013 and 2012 (in thousands, except for exercise prices and contractual terms):
 
Options
Outstanding
 
Weighted-
Average
Exercise
Price
 
Weighted-
Average
Remaining
Contractual
Term
(in years)
 
Aggregate
Intrinsic Value
December 31, 2011
8,280

 
$
7.70

 
5.90
 
$
127,308

Granted
1,595

 
22.59

 
 
 
 
Exercised
(3,128
)
 
0.72

 
 
 
 
Forfeitures and expired
(335
)
 
19.79

 
 
 
 
December 31, 2012
6,412

 
14.17

 
7.21
 
$
9,010

Granted
483

 
10.23

 
 
 
 
Exercised
(1,060
)
 
9.87

 
 
 
 
Forfeitures and expired
(345
)
 
20.65

 
 
 
 
December 31, 2013
5,490

 
14.25

 
6.52
 
$
28,769

Granted
403

 
14.35

 
 
 
 
Exercised
(388
)
 
8.01

 
 
 
 
Forfeitures and expired
(337
)
 
21.43

 
 
 
 
December 31, 2014
5,168

 
$
14.26

 
5.73
 
$
7,732

Vested and expected to vest at December 31, 2014
5,134

 
$
14.25

 
5.71
 
$
7,720

Exercisable at December 31, 2014
4,070

 
$
13.72

 
5.11
 
$
7,367

Summary of Assumptions Used for Options Granted
Below is a summary of the assumptions used for the stock options granted in the years indicated:
 
2014
 
2013
 
2012
Weighted average exercise price per share
$
14.35

 
$
10.23

 
$
22.59

Risk-free interest rate
2.0
%
 
1.0
%
 
1.2
%
Expected dividend yield

 

 

Expected volatility
55.1
%
 
58.9
%
 
54.6
%
Expected life (in years)
5.75

 
5.85

 
5.67

Forfeiture rate
6.0
%
 
5.0
%
 
4.0
%
Weighted average grant date fair value per share
$
7.43

 
$
5.48

 
$
11.26

Schedule of Share-based Payment Award, Equity Instruments Other than Options, Valuation Assumptions [Table Text Block] [Table Text Block]
The assumptions for the market-based portion of the PSUs granted in 2014 are noted in the following table:
 
2014
Grant price per share
$
11.54

Risk-free interest rate
1.4
%
Expected dividend yield

Historical volatility
50.0
%
Expected life (in years)
4.0

Forfeiture rate
6.0
%
Weighted average grant date fair value per share
$
5.39

Summary of Restricted Stock Units Activity
A summary of the RSU and PSU activity and related information is as follows:
 
Restricted Stock Units and Performance Stock Units
 
Time Based
 
Performance-Based
 
Market-Based
 
Number of Shares
 
Weighted Average
Grant Date
Fair Value
 
Number of Shares
 
Weighted Average
Grant Date
Fair Value
 
Number of Shares
 
Weighted Average
Grant Date
Fair Value
Balance at December 31, 2011
56,855

 
$
23.97

 

 
$

 

 
$

Awarded
362,199

 
9.72

 

 

 

 

Vested
(56,855
)
 
23.97

 

 

 

 

Canceled

 

 

 

 

 

Balance at December 31, 2012
362,199

 
9.72

 

 

 

 

Awarded
1,016,035

 
10.50

 

 

 

 

Vested
(181,104
)
 
9.72

 

 

 

 

Canceled
(98,613
)
 
10.39

 

 

 

 

Balance at December 31, 2013
1,098,517

 
10.38

 

 

 

 

Awarded
786,250

 
14.33

 

 

 
975,295

 
5.39

Vested
(393,106
)
 
10.15

 

 

 

 

Canceled
(212,572
)
 
11.89

 

 

 

 

Balance at December 31, 2014
1,279,089

 
$
12.63

 

 
$

 
975,295

 
$
5.39