CASH, CASH EQUIVALENTS, AND INVESTMENTS (Summary of Cash, Cash Equivalents, and Investments) (Details) - USD ($) $ in Thousands |
Sep. 30, 2016 |
Dec. 31, 2015 |
Sep. 30, 2015 |
Dec. 31, 2014 |
|---|---|---|---|---|
| Investment [Line Items] | ||||
| Cash and cash equivalents | $ 22,979 | $ 9,307 | $ 24,322 | $ 67,589 |
| Short-term investments | 4,908 | 50,523 | ||
| Long-term investments | 0 | 3,799 | ||
| Cash, cash equivalents, and investments | 27,887 | 63,629 | ||
| Cash | ||||
| Investment [Line Items] | ||||
| Cash and cash equivalents | 22,936 | 9,056 | ||
| Commercial paper and money market accounts | ||||
| Investment [Line Items] | ||||
| Cash and cash equivalents | 43 | 251 | ||
| Corporate bonds | ||||
| Investment [Line Items] | ||||
| Short-term investments | 3,900 | 49,518 | ||
| Long-term investments | 0 | 3,799 | ||
| Certificates of deposit and time deposits | ||||
| Investment [Line Items] | ||||
| Short-term investments | $ 1,008 | $ 1,005 |