DEBT (Tables)

9 Months Ended

Sep. 30, 2016

Debt

Schedule of principal amount of the Senior Notes is repayable

The principal amount of the Senior Notes is repayable as follows (amounts in thousands):

April 2, 2018	$	57,500
April 2, 2019		115,000
April 2, 2020		115,000
April 2, 2021		143,750
April 2, 2022		43,750
	$	475,000

Summary of the carrying value of the Senior Notes

The following is a summary of the carrying value of the Senior Notes as of September 30, 2016 and December 31, 2015 (in thousands):

	September 30,		December 31,
	2016		2015
Principal amount of the Senior Notes	$	475,000	$	575,000
Unamortized debt discount balance		(9,180)		(11,527)
Unamortized debt issuance costs		(367)		(461)
Principal amount of the Senior Notes - long-term	$	465,453	$	563,012

Summary of the liability component of the Convertible Notes

The following is a summary of the liability component of the Convertible Notes as of September 30, 2016 and December 31, 2015 (in thousands):

	September 30,		December 31,
	2016		2015
Principal amount of the Convertible Notes	$	345,000	$	345,000
Unamortized discount of the liability component		(91,306)		(101,965)
Unamortized debt issuance costs		(4,959)		(5,722)
Principal amount of the Convertible Notes - long-term	$	248,735	$	237,313

Senior Notes

Debt

Summary of interest expense for the Notes

The following is a summary of interest expense for the three and nine months ended September 30, 2016 and September 30, 2015 (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2016		2015		2016		2015
Contractual interest expense	$	13,049	$	15,796	$	41,671	$	31,078
Amortization of debt discount and debt issuance costs		581		487		1,663		958
Total interest expense	$	13,630	$	16,283	$	43,334	$	32,036

Convertible Notes

Debt

Summary of interest expense for the Notes

The following is a summary of interest expense for the three and nine months ended September 30, 2016 and September 30, 2015 (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2016		2015		2016		2015
Stated coupon interest	$	2,157	$	2,156	$	6,469	$	6,469
Amortization of debt discount and debt issuance costs		3,879		3,564		11,421		10,498
Total interest expense	$	6,036	$	5,720	$	17,890	$	16,967