FAIR VALUE INSTRUMENTS (Details) - USD ($) | Dec. 31, 2017 | Dec. 31, 2016 |
Fair Value, Inputs, Level 1 [Member] | | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | | |
Cash and Cash Equivalents, Fair Value Disclosure | $ 8,601,000 | $ 9,219,000 |
Fair Value, Inputs, Level 2 [Member] | | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | | |
Cash and Cash Equivalents, Fair Value Disclosure | 869,000 | 1,064,000 |
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 |
Fair Value, Measurements, Recurring [Member] | | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | | |
Cash and Cash Equivalents, Fair Value Disclosure | 9,470,000 | 10,283,000 |
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 | 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 | 352,000 | 350,000 |
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 | 0 |
Time Deposits [Member] | Fair Value, Measurements, Recurring [Member] | | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | | |
Cash and Cash Equivalents, Fair Value Disclosure | 352,000 | 350,000 |
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 | 1,633,000 | 2,182,000 |
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 |
Money Market Mutual Funds [Member] | Fair Value, Measurements, Recurring [Member] | | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | | |
Cash and Cash Equivalents, Fair Value Disclosure | 1,633,000 | 2,182,000 |
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 | 2,935,000 | |
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 | |
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 | |
U S T Bills [Member] | Fair Value, Measurements, Recurring [Member] | | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | | |
Cash and Cash Equivalents, Fair Value Disclosure | 2,935,000 | |
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 | 517,000 | 714,000 |
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 |
Corporate Debt Securities [Member] | Fair Value, Measurements, Recurring [Member] | | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | | |
Cash and Cash Equivalents, Fair Value Disclosure | 517,000 | 714,000 |
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 | 4,033,000 | 7,037,000 |
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 |
Marketable Equity Securities [Member] | Fair Value, Measurements, Recurring [Member] | | |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | | |
Cash and Cash Equivalents, Fair Value Disclosure | $ 4,033,000 | $ 7,037,000 |