DEBT (Tables)

3 Months Ended

Mar. 31, 2020

Long-term Debt, Unclassified [Abstract]

Summary of the carrying value of the Senior Notes

The following is a summary of the carrying value of the Senior Notes as of December 31, 2019 (in thousands): 

	December 31, 2019
Principal amount of the Senior Notes	$	162,500
Unamortized debt discount balance	(4,035		)
Unamortized debt issuance costs	(2,022		)
Total Senior Notes	$	156,443

Summary of interest expense for the Notes

The following is a summary of interest expense for the three months ended March 31, 2020 and 2019 (in thousands): 

	Three Months Ended March 31,
	2020		2019
Contractual interest expense	$	1,648	$	8,206
Amortization of debt discount and debt issuance costs	2,699		1,357
Total interest expense Senior Notes	$	4,347	$	9,563

The following is a summary of interest expense for the three months ended March 31, 2020 and 2019 (in thousands):

	Three Months Ended March 31,
	2020		2019
Stated coupon interest	$	607	$	2,156
Amortization of debt discount and debt issuance costs	1,469		4,807
Total interest expense 2021 Notes	$	2,076	$	6,963

 

The following is a summary of interest expense for the 2024 Notes for three months ended March 31, 2020 (in thousands):

	Three Months Ended March 31, 2020
Stated coupon interest	$	1,047
Amortization of debt discount and debt issuance costs	1,219
Total interest expense 2024 Notes	$	2,266

Summary of the liability component of the Convertible Notes

The 2024 Notes are not convertible or redeemable as of March 31, 2020. The following is a summary of the liability component of the 2024 Notes as of March 31, 2020 and December 31, 2019 (in thousands):

	March 31, 2020			December 31, 2019
Principal amount of the 2024 Notes	$	34,522		$	120,000
Unamortized discount of the liability component	(14,373		)	(51,701		)
Unamortized debt issuance costs	(797		)	(2,796		)
Total 2024 Notes	$	19,352		$	65,503

The following is a summary of the liability component of the 2021 Notes as of March 31, 2020 and December 31, 2019 (in thousands):

	March 31, 2020			December 31, 2019
Principal amount of the 2021 Notes	$	42,465		$	145,000
Unamortized discount of the liability component	(3,767		)	(14,963		)
Unamortized debt issuance costs	(184		)	(725		)
Total 2021 Notes	$	38,514		$	129,312