Quarterly report pursuant to Section 13 or 15(d)

Revenue (Major Customers) (Details)

v3.19.1
Revenue (Major Customers) (Details)
3 Months Ended
Mar. 31, 2019
Mar. 31, 2018
Revenues | Customer concentration risk | Fidelity    
Major Customers    
Revenue as a percentage of the company's total 16.00% 16.00%