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CASH, CASH EQUIVALENTS AND INVESTMENTS (Tables) | 3 Months Ended
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Mar. 31, 2018
Cash And Cash Equivalents [Abstract] |
Schedule of Cash, Cash Equivalents and Investments | Investments as of March 31, 2018 and December 31, 2017 consisted of the following (in thousands):
|  | Amortized |  |  | Unrealized |  |  | Aggregate Fair |
Investment Classification |  | Cost |  |  | Gains |  |  | (Losses) |  |  | Market Value |
March 31, 2018 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Certificates of deposit |  | $ | 1,499 |  |  | $ | 2 |  |  | $ | (1 | ) |  | $ | 1,500 |
Corporate bonds |  |  | 189,124 |  |  |  | 5 |  |  |  | (139 | ) |  |  | 188,990 |
U.S. Government securities |  |  | 131,644 |  |  |  | — |  |  |  | (187 | ) |  |  | 131,457 |
|  | $ | 322,267 |  |  | $ | 7 |  |  | $ | (327 | ) |  | $ | 321,947 |
December 31, 2017 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Certificates of deposit |  | $ | 1,296 |  |  | $ | 1 |  |  | $ | (1 | ) |  | $ | 1,296 |
Corporate bonds |  |  | 104,626 |  |  |  | — |  |  |  | (252 | ) |  |  | 104,374 |
U.S. Government securities |  |  | 214,641 |  |  |  | — |  |  |  | (139 | ) |  |  | 214,502 |
|  | $ | 320,563 |  |  | $ | 1 |  |  | $ | (392 | ) |  | $ | 320,172 |

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- Definition Tabular disclosure of the components of cash, cash equivalents, and investments. + References No definition available. + Details
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