MARKETABLE SECURITIES (Details) - USD ($) |
Jun. 30, 2020 |
Dec. 31, 2019 |
|---|---|---|
| Fair Value [Member] | ||
| Certificates of deposit | $ 9,572,000 | $ 8,959,000 |
| Fixed income mutual funds | 8,628,000 | 7,879,000 |
| Corporate bonds and notes | 5,563,000 | 8,892,000 |
| Total marketable securities | 23,763,000 | 25,730,000 |
| Cost Basis [Member] | ||
| Certificates of deposit | 9,516,000 | 8,953,000 |
| Fixed income mutual funds | 8,692,000 | 7,878,000 |
| Corporate bonds and notes | 5,492,000 | 8,813,000 |
| Total marketable securities | 23,700,000 | 25,644,000 |
| Gross Unrealized Gains [Member] | ||
| Certificates of deposit | 56,000 | 6,000 |
| Fixed income mutual funds | 0 | 1,000 |
| Corporate bonds and notes | 88,000 | 112,000 |
| Total marketable securities | 144,000 | 119,000 |
| Gross Unrealized Losses [Member] | ||
| Certificates of deposit | 0 | 0 |
| Fixed income mutual funds | (64,000) | 0 |
| Corporate bonds and notes | (17,000) | (33,000) |
| Total marketable securities | $ (81,000) | $ (33,000) |