Quarterly report pursuant to sections 13 or 15(d)

Securities Owned and Securities Sold, But Not Yet Purchased - Additional Information (Detail)

v2.3.0.11
Securities Owned and Securities Sold, But Not Yet Purchased - Additional Information (Detail) (USD $)
In Thousands
Jun. 30, 2012
Dec. 31, 2011
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities owned deposited with the Company's subsidiaries clearing broker $ 448 $ 542
Securities owned at fair value 1,336 2,014
Common stock and warrants | Fair Value, Inputs, Level 2 | Warrants to purchase common stock
   
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities owned at fair value 575 1,005
Common stock and warrants
   
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Securities owned at fair value $ 328 $ 191