Quarterly report pursuant to Section 13 or 15(d)

Debt Instruments - Convertible Debt Offering (Details)

v3.5.0.2
Debt Instruments - Convertible Debt Offering (Details)
$ / shares in Units, shares in Millions
9 Months Ended
Dec. 09, 2015
USD ($)
$ / shares
$ / unit
Sep. 30, 2016
USD ($)
day
$ / shares
shares
Debt Instruments    
Closing price of common stock (in dollars per share) | $ / shares   $ 14.33
Convertible debt | Notes    
Debt Instruments    
Aggregate principal amount $ 345,000,000.0  
Interest rate 1.75%  
Net proceeds from sale of debt $ 336,500,000  
Payments for capped call transactions $ 43,200,000  
Debt instrument, conversion ratio 0.0609050  
Debt instrument, conversion price (in dollars per share) | $ / shares $ 16.42  
Value of debt $ 233,500,000 $ 362,100,000
Carrying amount of equity component reported in additional paid-in-capital 103,000,000.0  
Debt fees and expenses $ 2,600,000  
Initial cap price (in dollars per share) | $ / unit 25.26  
Convertible debt | Notes | After December 5, 2018    
Debt Instruments    
Debt instrument, threshold percentage of stock price trigger   130.00%
Debt instrument, threshold trading days | day   20
Debt instrument, threshold consecutive trading days   30 days
Debt instrument, threshold notice trading days | day   5
Debt instrument, redemption price, percentage of principal   100.00%
Convertible debt | Notes | Preceding July 1, 2020, after the quarter ending on March 31, 2016 and additional criteria    
Debt Instruments    
Debt instrument, threshold percentage of stock price trigger   130.00%
Debt instrument, threshold trading days | day   20
Debt instrument, threshold consecutive trading days   30 days
Convertible debt | Notes | Preceding July 1, 2020, after the measurement period and additional criteria    
Debt Instruments    
Debt instrument, threshold note trading days | day   5
Debt instrument, threshold consecutive note trading days   10 days
Debt instrument, threshold principle amount of note trigger   $ 1,000
Debt instrument, threshold percentage of note price trigger (less than)   98.00%
Maximum | Convertible debt | Notes    
Debt Instruments    
Debt conversion, maximum number of shares of common stock convertible by Notes | shares   27.3