INDEBTEDNESS (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Principal amount	$ 143,750	$ 143,750
Unamortized debt discount	(10,427)	(13,924)
Deferred financing costs	(1,196)	(1,618)
Net carrying value	$ 132,127	$ 128,208

Carrying amount of long-term convertible debt as of the balance sheet date, net of the amount due in the next twelve months or greater than the normal operating cycle, if longer. The debt is convertible into another form of financial instrument, typically the entity's common stock.

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Balance Type:	credit
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- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Amount, after accumulated amortization, of debt discount.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
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+ Details

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Balance Type:	debit
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- Definition

Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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+ Details

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Balance Type:	debit
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