MARKETABLE SECURITIES (Details) - USD ($) |
Sep. 30, 2020 |
Dec. 31, 2019 |
|---|---|---|
| Fair Value [Member] | ||
| Certificates of deposit | $ 8,304,000 | $ 8,959,000 |
| Fixed income mutual funds | 9,592,000 | 7,879,000 |
| Corporate bonds and notes | 3,375,000 | 8,892,000 |
| Total marketable securities | 21,271,000 | 25,730,000 |
| Cost Basis [Member] | ||
| Certificates of deposit | 8,282,000 | 8,953,000 |
| Fixed income mutual funds | 9,616,000 | 7,878,000 |
| Corporate bonds and notes | 3,371,000 | 8,813,000 |
| Total marketable securities | 21,269,000 | 25,644,000 |
| Gross Unrealized Gains [Member] | ||
| Certificates of deposit | 22,000 | 6,000 |
| Fixed income mutual funds | 0 | 1,000 |
| Corporate bonds and notes | 26,000 | 112,000 |
| Total marketable securities | 48,000 | 119,000 |
| Gross Unrealized Losses [Member] | ||
| Certificates of deposit | 0 | 0 |
| Fixed income mutual funds | (24,000) | 0 |
| Corporate bonds and notes | (22,000) | (33,000) |
| Total marketable securities | $ (46,000) | $ (33,000) |