Receivables from and Payable to Brokers, Dealers and Clearing Organizations (Schedule of Amounts Receivable) (Details) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Receivables from clearing and other brokers
NFS	$ 1,408,000	$ 1,664,000
StockCross	708,000	310,000
Other receivables	117,000	31,000
Citibank	42,000	25,000
Total Receivables from clearing and other brokers	2,275,000	2,030,000
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
KCA	33,000
StockCross	21,000	46,000
MSCO	10,000	29,000
NFS		58,000
Total Due to clearing brokers and related parties	$ 64,000	$ 133,000