FAIR VALUE INSTRUMENTS (Details) - USD ($) | Dec. 31, 2019 | Dec. 31, 2018 |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | | |
Cash and Cash Equivalents, Fair Value Disclosure | $ 18,209,000 | $ 22,454,000 |
Fair Value, Inputs, Level 1 [Member] | | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | | |
Cash and Cash Equivalents, Fair Value Disclosure | 17,735,000 | 21,597,000 |
Fair Value, Inputs, Level 2 [Member] | | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | | |
Cash and Cash Equivalents, Fair Value Disclosure | 474,000 | 857,000 |
Fair Value, Inputs, Level 3 [Member] | | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | | |
Cash and Cash Equivalents, Fair Value Disclosure | 0 | 0 |
Time Deposits [Member] | | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | | |
Cash and Cash Equivalents, Fair Value Disclosure | | 355,000 |
Time Deposits [Member] | Fair Value, Inputs, Level 1 [Member] | | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | | |
Cash and Cash Equivalents, Fair Value Disclosure | | 0 |
Time Deposits [Member] | Fair Value, Inputs, Level 2 [Member] | | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | | |
Cash and Cash Equivalents, Fair Value Disclosure | | 355,000 |
Time Deposits [Member] | Fair Value, Inputs, Level 3 [Member] | | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | | |
Cash and Cash Equivalents, Fair Value Disclosure | | 0 |
Money Market Mutual Funds [Member] | | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | | |
Cash and Cash Equivalents, Fair Value Disclosure | 606,000 | 1,594,000 |
Money Market Mutual Funds [Member] | Fair Value, Inputs, Level 1 [Member] | | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | | |
Cash and Cash Equivalents, Fair Value Disclosure | 606,000 | 1,594,000 |
Money Market Mutual Funds [Member] | Fair Value, Inputs, Level 2 [Member] | | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | | |
Cash and Cash Equivalents, Fair Value Disclosure | 0 | 0 |
Money Market Mutual Funds [Member] | Fair Value, Inputs, Level 3 [Member] | | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | | |
Cash and Cash Equivalents, Fair Value Disclosure | 0 | 0 |
U S T bills [Member] | | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | | |
Cash and Cash Equivalents, Fair Value Disclosure | 14,130,000 | 17,429,000 |
U S T bills [Member] | Fair Value, Inputs, Level 1 [Member] | | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | | |
Cash and Cash Equivalents, Fair Value Disclosure | 14,130,000 | 17,429,000 |
U S T bills [Member] | Fair Value, Inputs, Level 2 [Member] | | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | | |
Cash and Cash Equivalents, Fair Value Disclosure | 0 | 0 |
U S T bills [Member] | Fair Value, Inputs, Level 3 [Member] | | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | | |
Cash and Cash Equivalents, Fair Value Disclosure | 0 | |
Corporate Debt Securities [Member] | | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | | |
Cash and Cash Equivalents, Fair Value Disclosure | 474,000 | 502,000 |
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member] | | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | | |
Cash and Cash Equivalents, Fair Value Disclosure | 0 | 0 |
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member] | | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | | |
Cash and Cash Equivalents, Fair Value Disclosure | 474,000 | 502,000 |
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member] | | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | | |
Cash and Cash Equivalents, Fair Value Disclosure | 0 | 0 |
Marketable Equity Securities [Member] | | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | | |
Cash and Cash Equivalents, Fair Value Disclosure | 2,999,000 | 2,574,000 |
Marketable Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member] | | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | | |
Cash and Cash Equivalents, Fair Value Disclosure | 2,999,000 | 2,574,000 |
Marketable Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member] | | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | | |
Cash and Cash Equivalents, Fair Value Disclosure | 0 | 0 |
Marketable Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member] | | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | | |
Cash and Cash Equivalents, Fair Value Disclosure | $ 0 | $ 0 |