Quarterly report pursuant to Section 13 or 15(d)

Segment and Geographic Information - Additional Information (Details)

v3.10.0.1
Segment and Geographic Information - Additional Information (Details) - Segment
3 Months Ended 6 Months Ended
Jun. 30, 2018
Jun. 30, 2017
Jun. 30, 2018
Jun. 30, 2017
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]        
Number of Reportable Segments     1  
Customer Concentration Risk | Sales Revenue, Net        
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]        
Concentration risk, percentage 48.00% 53.00% 49.00% 47.00%
United Kingdom | Customer Concentration Risk | Sales Revenue, Net        
Segment Reporting Reconciling Item For Operating Profit Loss From Segment To Consolidated [Line Items]        
Concentration risk, percentage     50.00% 54.00%