Long-term Debt (Tables)

6 Months Ended

Jun. 30, 2020

Long-term Debt

Schedule of Future Annual Principal Payments on Convertible Senior Notes

The following is a summary of our convertible senior notes at June 30, 2020:

		Principal Amount
	Interest Rate		(in thousands)	Due Date
2021 Notes	2.50%	$	64,418	September 15, 2021
2024 Notes	4.50%		150,624	August 1, 2024
2025 Notes	1.25%		300,000	May 1, 2025
Total		$	515,042

Schedule of Total Interest Expense Recognized Related to Notes

	Three months ended June 30,				Six months ended June 30,
	2020		2019		2020		2019
Interest on convertible notes	$	2,811	$	2,734	$	5,994	$	5,469
Amortization of debt issuance costs		637		679		1,423		1,324
Debt issuance cost derecognized related to convertible debt transactions		789		—		4,344		—
Interest on finance lease		208		179		423		363
Interest on borrowings under financing agreement		2,264		199		4,055		199
Other interest		30		26		61		52
Total interest expense	$	6,739	$	3,817	$	16,300	$	7,407