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Stock-based Compensation Plans and Awards - Employee Stock Purchase Plan - Additional Information (Details)
$ in Thousands
1 Months Ended 12 Months Ended
May. 31, 2011
Dec. 31, 2015
USD ($)
item
shares
Dec. 31, 2014
USD ($)
Dec. 31, 2013
USD ($)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Stock-based compensation expense | $   $ 7,562 $ 21,815 $ 27,384
Employee Stock Purchase Plan        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Share-based compensation arrangement by share-based payment award, discount from market price, lower of purchase and offer date 15.00%      
Participants maximum payroll deductions percentage 15.00%      
Duration of each offering period   24 months    
Number of purchase periods in each offering period | item   4    
Duration of each purchase period   6 months    
Maximum number of common stock shares may be purchased by each participant | shares   750    
Duration of each interval in each purchase period within an offering   6 months    
Fair value assumptions, expected life   24 months    
Fair value assumptions, expected volatility, minimum   58.00%    
Fair value assumptions, expected volatility, maximum   60.00%    
Stock-based compensation expense | $   $ 500   $ 1,800
Number of common stock shares remaining authorized for issuance | shares   1,700,000