Debt (Tables)

9 Months Ended

Sep. 30, 2018

Schedule of outstanding debt obligations

Our outstanding debt obligations as of September 30, 2018 and December 31, 2017 consisted of the following (in thousands):



	September 30, 2018			December 31, 2017
2023 Senior Notes	$	—		$	466,291
2022 Convertible Notes	258,376			248,194
2019 Convertible Notes	20,999			20,198
Total long-term debt	279,375			734,683
Less: current maturities	(20,999		)	—
Long-term debt, net of current maturities	$	258,376		$	734,683

Schedule of outstanding convertible debt

The outstanding balances of our Convertible Notes as of September 30, 2018 consisted of the following (in thousands):



	2022 Convertible Notes		2019 Convertible Notes		Total
Liability component:
Principal	$	320,000	$	21,417	$	341,417
Less: debt discount and issuance costs, net	61,624		418		62,042
Net carrying amount	$	258,376	$	20,999	$	279,375
Equity Component	$	72,576	$	9,905	$	82,481

Schedule of total interest expense recognized related to the convertible debt

The following table sets forth total interest expense recognized related to the Convertible Notes during the three and nine months ended September 30, 2018 and 2017 (in thousands):



	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
Contractual interest expense	$	2,734	$	2,840	$	8,202	$	6,033
Amortization of debt issuance costs	355		348		1,040		944
Amortization of debt discount	3,391		3,264		9,942		7,909
Total interest expense	$	6,480	$	6,452	$	19,184	$	14,886

Schedule of future annual principal payments on long-term debt

Future annual principal payments on our long-term debt as of September 30, 2018 were as follows (in thousands):



Period	Future Annual Principal Payments
Remainder of Year Ending December 31, 2018	$	—
Year Ending December 31, 2019	21,417
Year Ending December 31, 2020	—
Year Ending December 31, 2021	—
Year Ending December 31, 2022	320,000
Thereafter	—
Total	$	341,417