Receivables from and Payable to Brokers, Dealers and Clearing Organizations (Schedule of Amounts Receivable) (Details) - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Receivables from clearing and other brokers
National Financial Services ("NFS")	$ 1,632,000	$ 1,664,000
StockCross	631,000	311,000
Total Receivables from clearing and other brokers	2,263,000	1,975,000
Receivable from related party
StockCross	1,000,000	1,000,000
Total Receivable from related party	1,000,000	1,000,000
Due to clearing brokers and related parties
PWC	15,000
MSCO	2,000	29,000
StockCross		46,000
NFS		58,000
Total Due to clearing brokers and related parties	$ 17,000	$ 133,000