Income Taxes - (Narrative) (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Income Taxes [Line Items]      
Increase (decrease) in valuation allowance $ (2,400) $ 15,900 $ 15,900
Unrecognized Tax Benefits 4,342  
Federal      
Income Taxes [Line Items]      
Net operating loss carryforwards 178,100    
Research and development tax credits $ 17,400    
Federal | Minimum      
Income Taxes [Line Items]      
Net operating loss carryforwards, expiration year 2019    
Research and development tax credit, expiration year 2019    
Federal | Maximum      
Income Taxes [Line Items]      
Net operating loss carryforwards, expiration year 2035    
Research and development tax credit, expiration year 2035    
California State      
Income Taxes [Line Items]      
Net operating loss carryforwards $ 116,200    
Research and development tax credits $ 2,800    
California State | Minimum      
Income Taxes [Line Items]      
Net operating loss carryforwards, expiration year 2016    
California State | Maximum      
Income Taxes [Line Items]      
Net operating loss carryforwards, expiration year 2035    
Other States [Member]      
Income Taxes [Line Items]      
Net operating loss carryforwards $ 27,900    
Other States [Member] | Minimum      
Income Taxes [Line Items]      
Net operating loss carryforwards, expiration year 2023    
Other States [Member] | Maximum      
Income Taxes [Line Items]      
Net operating loss carryforwards, expiration year 2035