XML 30 R19.htm IDEA: XBRL DOCUMENT

Customer Concentration	3 Months Ended
Customer Concentration	Mar. 31, 2016
Risks And Uncertainties [Abstract]
Customer Concentration	11. Customer Concentration During both the three months ended March 31, 2016 and 2015, no single client accounted for more than 10% of total revenue. One institutional investor client accounted for 16.4% and 13.2% of trading volumes during the three months ended March 31, 2016 and 2015, respectively.