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NET INCOME (LOSS) PER SHARE - Narrative (Details) - $ / shares | Mar. 31, 2017 | Dec. 31, 2016 | Mar. 31, 2015 | Dec. 31, 2012
--- | --- | --- | --- | ---
4.50% convertible subordinated notes |  |  |  |
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |  |  |  |
Stated interest rate (as a percent) | 4.50% | 4.50% |  | 4.50%
Conversion price (usd per share) | $ 13.2 |  | $ 34.64 | $ 13.20
3.50% convertible subordinated notes |  |  |  |
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |  |  |  |
Stated interest rate (as a percent) | 3.50% |  | 3.50% |

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