Annual report pursuant to Section 13 and 15(d)

Long-term Borrowings - Additional Information (Details)

v3.10.0.1
Long-term Borrowings - Additional Information (Details) - USD ($)
12 Months Ended
Sep. 28, 2018
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Apr. 09, 2016
Debt Instrument [Line Items]          
Outstanding principal amount   $ 60,000      
Unamortized discount and deferred financing costs   3,000,000      
Non-current restricted cash   49,875,000 $ 0 $ 0 $ 0
Voluntary principal payment, minimum amount   5,000,000      
Voluntary principal payment, integral multiples in excess thereof   $ 1,000,000      
Early termination premium (as a percentage)   1.00%      
LIBOR          
Debt Instrument [Line Items]          
Basis on variable rate, first year (as a percentage)   5.00%      
Basis on variable rate, second year (as a percentage)   7.00%      
Basis on variable rate, thereafter (as a percentage)   8.00%      
Term Loan          
Debt Instrument [Line Items]          
Debt term (in years) 3 years        
Principal amount $ 60,000,000.0        
Principal amount as a percentage of par amount 99.00%        
Discount $ 600,000        
Fees $ 2,600,000        
Outstanding principal amount   $ 60,000,000      
Non-current restricted cash   49,600,000      
Interest expense   $ 1,200,000