XML 32 R19.htm IDEA: XBRL DOCUMENT

Customer Concentration	9 Months Ended
Customer Concentration	Sep. 30, 2017
Risks And Uncertainties [Abstract]
Customer Concentration	11. Customer Concentration During both the nine months ended September 30, 2017 and 2016, no single client accounted for more than 10% of total revenue. One institutional investor client accounted for 12.8% and 14.6% of trading volumes during the nine months ended September 30, 2017 and 2016, respectively.