CONCENTRATION OF RISK - Revenues by Geographic Area (Details) - USD ($) $ in Thousands |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2016 |
Sep. 30, 2015 |
Sep. 30, 2016 |
Sep. 30, 2015 |
|
| Concentration Risk [Line Items] | ||||
| Revenues | $ 30,214 | $ 39,419 | $ 124,309 | $ 128,734 |
| South Korea [Member] | ||||
| Concentration Risk [Line Items] | ||||
| Revenues | 24,852 | 34,514 | 111,994 | 110,547 |
| China [Member] | ||||
| Concentration Risk [Line Items] | ||||
| Revenues | 2,095 | 843 | 5,663 | 1,523 |
| Japan [Member] | ||||
| Concentration Risk [Line Items] | ||||
| Revenues | 1,230 | 3,274 | 3,334 | 13,931 |
| Other Non-U.S. Locations [Member] | ||||
| Concentration Risk [Line Items] | ||||
| Revenues | 396 | 523 | 1,416 | 1,726 |
| Total Non-U.S. Locations [Member] | ||||
| Concentration Risk [Line Items] | ||||
| Revenues | 28,573 | 39,154 | 122,407 | 127,727 |
| UNITED STATES | ||||
| Concentration Risk [Line Items] | ||||
| Revenues | $ 1,641 | $ 265 | $ 1,902 | $ 1,007 |