MARKETABLE SECURITIES (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Fair Value [Member]
Certificates of deposit	$ 8,959,000	$ 13,151,000
Fixed income mutual funds	7,879,000	9,640,000
Corporate bonds and notes	8,892,000	8,437,000
Total marketable securities	25,730,000	31,228,000
Cost Basis [Member]
Certificates of deposit	8,953,000	13,151,000
Fixed income mutual funds	7,878,000	9,648,000
Corporate bonds and notes	8,813,000	8,518,000
Total marketable securities	25,644,000	31,317,000
Gross Unrealized Gains [Member]
Certificates of deposit	6,000
Fixed income mutual funds	1,000
Corporate bonds and notes	112,000
Total marketable securities	119,000
Gross Unrealized Losses [Member]
Certificates of deposit
Fixed income mutual funds		(8,000)
Corporate bonds and notes	(33,000)	(81,000)
Total marketable securities	$ (33,000)	$ (89,000)