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CONVERTIBLE SENIOR NOTES (Details) (USD $)
In Thousands, except Share data, unless otherwise specified
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12 Months Ended |
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0 Months Ended |
12 Months Ended |
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Dec. 31, 2013
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Dec. 31, 2012
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Dec. 31, 2011
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Jun. 30, 2013
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Jul. 27, 2010
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Jul. 27, 2010
5.00% convertible senior notes [Member]
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Dec. 31, 2013
5.00% convertible senior notes [Member]
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Dec. 31, 2012
5.00% convertible senior notes [Member]
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Dec. 31, 2011
5.00% convertible senior notes [Member]
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| Convertible senior notes |
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| 2010 Notes issued |
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$ 125,000 |
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| Interest rate on convertible notes (in hundredths) |
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5.00% |
5.00% |
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| Conversion rate of common stock per $1000 of principal amount of convertible notes (in shares) |
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51.0204 |
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| Principal amount used for debt instrument conversion ratio |
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1,000 |
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| Initial conversion price of convertible notes into common stock (in dollars per share) |
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$ 19.60 |
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| Premium on sale price to calculate exchange price of notes (as a percent) |
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22.50% |
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| Offering price of common stock (in dollars per share) |
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$ 1.63 |
$ 16.00 |
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| Number of shares to be converted into common stock (in shares) |
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6,377,551 |
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| Interest rate assumed for estimating fair value of the liability component (as a percent) |
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10.00% |
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| Estimated fair value of liability component |
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100,625 |
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| Estimated fair value of conversion option |
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24,375 |
24,375 |
24,375 |
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| Issuance costs allocated to equity component |
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918 |
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| Issuance costs allocated to liability component |
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3,637 |
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| Amortization period of debt issuance costs |
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5 years |
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| Percentage of principal amount at which the note may be repurchased prior to the maturity date of note |
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100.00% |
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| Carrying amount of the equity component (additional paid-in capital) |
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24,375 |
24,375 |
24,375 |
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| Principal amount of the 2010 Notes |
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125,000 |
125,000 |
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| Unamortized discount of the liability component |
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9,119 |
14,082 |
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| Net carrying amount of the liability component |
0 |
110,918 |
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115,881 |
110,918 |
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| Effective interest rate on liability component (as a percent) |
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10.00% |
10.00% |
10.00% |
| Cash interest expense recognized |
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6,250 |
6,263 |
6,231 |
| Non-cash interest expense recognized |
4,963 |
4,537 |
4,072 |
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4,963 |
4,537 |
4,072 |
| Non-cash deferred financing amortization costs included in interest expense |
9,116 |
5,413 |
3,188 |
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720 |
722 |
720 |
| Remaining period over which the unamortized discount will be recognized |
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1 year 7 months 6 days |
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| Line of credit facility leverage covenant, maximum ratio of financial indebtedness to total assets |
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$ 50,000 |
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| Maturity date of convertible notes |
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Aug. 15,
2015 |
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