Quarterly report pursuant to Section 13 or 15(d)

Basis of Presentation and Significant Accounting Policies - Additional Information (Details)

v3.8.0.1
Basis of Presentation and Significant Accounting Policies - Additional Information (Details)
3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2017
USD ($)
Customer
Sep. 30, 2016
USD ($)
Customer
Sep. 30, 2017
USD ($)
Customer
Sep. 30, 2016
USD ($)
Customer
Dec. 31, 2016
Customer
Basis Of Presentation And Significant Accounting Policies [Line Items]          
Unrecognized tax benefits, income tax penalties or interest charged     $ 0    
Allocation of undistributed earnings to participating securities $ 10,306,000 $ 0 $ 3,703,000 $ 0  
Contractual obligation   $ 0   $ 0  
Customer Concentration Risk [Member] | Trade Receivables [Member]          
Basis Of Presentation And Significant Accounting Policies [Line Items]          
Number of major customers | Customer     2   1
Customer Concentration Risk [Member] | Trade Receivables [Member] | Customer 1 [Member]          
Basis Of Presentation And Significant Accounting Policies [Line Items]          
Concentration risk, percentage (in hundredths)     55.00%   85.00%
Customer Concentration Risk [Member] | Trade Receivables [Member] | Customer 2 [Member]          
Basis Of Presentation And Significant Accounting Policies [Line Items]          
Concentration risk, percentage (in hundredths)     45.00%    
Customer Concentration Risk [Member] | Revenues [Member]          
Basis Of Presentation And Significant Accounting Policies [Line Items]          
Number of major customers | Customer 1 3 1 4  
Customer Concentration Risk [Member] | Revenues [Member] | Customer 1 [Member]          
Basis Of Presentation And Significant Accounting Policies [Line Items]          
Concentration risk, percentage (in hundredths) 98.00% 51.00% 96.00% 30.00%  
Customer Concentration Risk [Member] | Revenues [Member] | Customer 2 [Member]          
Basis Of Presentation And Significant Accounting Policies [Line Items]          
Concentration risk, percentage (in hundredths)   37.00%   21.00%  
Customer Concentration Risk [Member] | Revenues [Member] | Customer 3 [Member]          
Basis Of Presentation And Significant Accounting Policies [Line Items]          
Concentration risk, percentage (in hundredths)   12.00%   18.00%  
Customer Concentration Risk [Member] | Revenues [Member] | Customer 4 [Member]          
Basis Of Presentation And Significant Accounting Policies [Line Items]          
Concentration risk, percentage (in hundredths)       10.00%