4. Gross unrealized losses and fair values of investments by investment category and the length of time (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013
Less than 12 Months
Fair Value	$ 231,000
Unrealized Loss	(19,000)
Greater than 12 Months
Fair Value	581,000	592,000
Unrealized Loss	(63,000)	(87,000)
Total
Fair Value	812,000	592,000
Unrealized Loss	(82,000)	(87,000)
Partnerships owning investments in technology related industries
Less than 12 Months
Fair Value
Unrealized Loss
Greater than 12 Months
Fair Value	370,000	346,000
Unrealized Loss	(56,000)	(76,000)
Total
Fair Value	370,000	346,000
Unrealized Loss	(56,000)	(76,000)
Partnerships owning real estate and related investments
Less than 12 Months
Fair Value
Unrealized Loss
Greater than 12 Months
Fair Value	211,000	246,000
Unrealized Loss	(7,000)	(11,000)
Total
Fair Value	211,000	246,000
Unrealized Loss	(7,000)	(11,000)
Other investments
Less than 12 Months
Fair Value	231,000
Unrealized Loss	(19,000)
Greater than 12 Months
Fair Value
Unrealized Loss
Total
Fair Value	231,000
Unrealized Loss	$ (19,000)