Debt (Tables)

9 Months Ended

Sep. 30, 2019

Schedule of outstanding debt obligations

Our outstanding debt obligations as of September 30, 2019 and December 31, 2018 consisted of the following (in thousands):



	September 30, 2019		December 31, 2018
2022 Convertible Notes	$	273,124	$	261,933
2019 Convertible Notes	—		21,276
Total long-term debt	273,124		283,209
Less: current maturities	—		21,276
Long-term debt, net of current maturities	$	273,124	$	261,933

Schedule of outstanding convertible debt

The outstanding balance of our 2022 Convertible Notes as of September 30, 2019 consisted of the following (in thousands):



	2022 Convertible Notes
Liability component:
Principal	$	320,000
Less: debt discount and issuance costs, net	46,876
Net carrying amount	$	273,124
Gross equity component	$	72,576

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, 2019 and 2018 (in thousands):



	Three Months Ended September 30,				Nine Months Ended September 30,
	2019		2018		2019		2018
Contractual interest expense	$	2,600	$	2,734	$	7,867	$	8,202
Amortization of debt issuance costs	353		355		1,051		1,040
Amortization of debt discount	3,466		3,391		10,281		9,942
Total interest expense	$	6,419	$	6,480	$	19,199	$	19,184

Schedule of future annual principal payments on long-term debt

Future annual principal payments on our long-term debt as of September 30, 2019 were as follows (in thousands):



Period	Future Annual Principal Payments
Remainder of Year Ending December 31, 2019	$	—
Year Ending December 31, 2020	—
Year Ending December 31, 2021	—
Year Ending December 31, 2022	320,000
Year Ending December 31, 2023	—
Thereafter	—
Total	$	320,000