Customer Concentration	12 Months Ended
Dec. 31, 2012
Customer Concentration [Abstract]
Customer Concentration	15. Customer Concentration During the years ended December 31, 2012, 2011 and 2010, no single client accounted for more than 10% of total revenue. One institutional investor client accounted for approximately 13.5%, 14.6% and 15.8% of trading volumes during the years ended December 31, 2012, 2011 and 2010, respectively. This institutional investor client also beneficially owns approximately 7% of the outstanding shares of the Company’s common stock.

The entire disclosure for any concentrations existing at the date of the financial statements that make an entity vulnerable to a reasonably possible, near-term, severe impact. This disclosure informs financial statement users about the general nature of the risk associated with the concentration, and may indicate the percentage of concentration risk as of the balance sheet date.

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-Name Statement of Position (SOP)

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+ Details