Restatement of previously issued financial statements due to correction of errors (Details Textual) (USD $)
12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Dec. 31, 2008
Dec. 31, 2007
Provision for State Sales Tax $ 470,000 $ 266,000        
Sales and Excise Tax Payable, Current 736,000 266,000        
Due from Affiliate, Noncurrent           6,800,000
Impairment Charge On Note Receivable         5,800,000  
Impairment recovery on note receivable from affiliate   1,200,000 4,300,000 300,000    
Revenue Period, Increase Decrease 4,600,000          
Deferred Revenue, Period Increase (Decrease)   $ 2,400,000