Annual report pursuant to Section 13 and 15(d)

Income Taxes - Additional Information (Details)

v3.8.0.1
Income Taxes - Additional Information (Details) - USD ($)
 3 Months Ended 12 Months Ended
Dec. 31, 2017
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Income Tax Disclosure [Abstract]          
Federal income tax provision, current     $ 0 $ 0 $ 0
Subsequent Event [Line Items]          
Federal tax expense, at statutory rate     35.00% 35.00% 35.00%
Adjustment of deferred tax assets $ (184,599,000)   $ (184,599,000)    
Federal tax reform - deferred rate change     14.60% 0.00% 0.00%
Effective income tax rate percent     48.70% 31.70% 42.90%
New Accounting Pronouncements or Change in Accounting Principle [Line Items]          
Tax credit     $ 21,700,000 $ 66,326,000  
Operating Loss Carryforwards [Line Items]          
Valuation allowance 52,883,000   52,883,000 47,682,000  
Unrecognized tax benefits 334,254,000   334,254,000 303,583,000 $ 253,277,000
Unrecognized tax benefits that would impact effective tax rate 256,525,000   256,525,000    
Uncertain tax positions are recognized in other long-term liabilities 12,190,000   12,190,000 4,780,000  
Penalties accrued $ 0   0    
Unrecognized tax benefits, increase resulting from interest     $ 708,000 100,000  
Forecast          
Subsequent Event [Line Items]          
Federal tax expense, at statutory rate   21.00%      
Domestic Tax Authority          
Operating Loss Carryforwards [Line Items]          
Operating loss carryforward       1,977,407,000  
Accounting Standards Update 2016-09          
New Accounting Pronouncements or Change in Accounting Principle [Line Items]          
Increase in deferred tax assets       $ 293,896,000