INDEBTEDNESS (Tables)

3 Months Ended

Mar. 31, 2020

Debt Disclosure [Abstract]

Net Carrying Amount of Convertible Notes

The net carrying amount of the Notes were as follows (in thousands):

	Principal outstanding		Unamortized debt discount		Unamortized debt issuance costs		Net carrying value
March 31, 2020
2025 Notes	$	1,000,000	$	(151,680)	$	(13,190)	$	835,130
2023 Notes	862,500		(103,016)		(3,186)		756,298
2022 Notes	186,251		(15,149)		(1,683)		169,419
Total	$	2,048,751	$	(269,845)	$	(18,059)	$	1,760,847
December 31, 2019
2023 Notes	$	862,500	$	(110,518)	$	(3,418)	$	748,564
2022 Notes	211,726		(19,312)		(2,146)		190,268
Total	$	1,074,226	$	(129,830)	$	(5,564)	$	938,832

The net carrying amount of the equity component of the Notes were as follows (in thousands):

	Amount allocated to conversion option		Less: allocated issuance costs		Equity component, net
March 31, 2020
2025 Notes	$	154,600	$	(2,342)	$	152,258
2023 Notes	155,250		(1,231)		154,019
2022 Notes	36,490		(974)		35,516
Total	$	346,340	$	(4,547)	$	341,793
December 31, 2019
2023 Notes	$	155,250	$	(1,231)	$	154,019
2022 Notes	41,481		(1,108)		40,373
Total	$	196,731	$	(2,339)	$	194,392

Interest Expense on Convertible Notes

The Company recognized interest expense on the Notes as follows (in thousands, except for percentages):

	Three Months Ended March 31,
	2020		2019
Contractual interest expense	$	1,373	$	1,277
Amortization of debt discount and issuance costs	12,528		9,608
Total	$	13,901	$	10,885