DEBT (Tables)

9 Months Ended

Sep. 30, 2017

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		87,500
	$	375,000

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, 2017 and December 31, 2016 (in thousands):

	September 30,		December 31,
	2017		2016
Principal amount of the Senior Notes	$	375,000	$	475,000
Unamortized debt discount balance		(5,551)		(8,605)
Unamortized debt issuance costs		(223)		(344)
	$	369,226	$	466,051

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, 2017 and December 31, 2016 (in thousands):

	September 30,		December 31,
	2017		2016
Principal amount of the Convertible Notes	$	345,000	$	345,000
Unamortized discount of the liability component		(75,892)		(87,570)
Unamortized debt issuance costs		(3,945)		(4,705)
	$	265,163	$	252,725

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, 2017 and September 30, 2016 (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2017		2016		2017		2016
Contractual interest expense	$	10,589		13,049		33,748		41,671
Amortization of debt discount and debt issuance costs		614		581		1,811		1,663
Total interest expense	$	11,203	$	13,630	$	35,559	$	43,334

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, 2017 and September 30, 2016 (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2017		2016		2017		2016
Stated coupon interest	$	2,156		2,157		6,468		6,469
Amortization of debt discount and debt issuance costs		4,225		3,879		12,438		11,421
Total interest expense	$	6,381	$	6,036	$	18,906	$	17,890