Convertible Senior Notes (Tables)

9 Months Ended

Oct. 31, 2020

Debt Disclosure [Abstract]

Convertible debt schedules

The net carrying amounts of the liability component of the 2024 Notes and 2026 Notes were as follows (in thousands):

	October 31, 2020
	2024 Notes		2026 Notes
Principal	$	90,001	$	1,150,000
Unamortized debt discount	(16,477)		(260,875)
Unamortized debt issuance costs	(1,338)		(13,659)
Net carrying amount	$	72,186	$	875,466

Interest expense related to Notes

The following table sets forth the interest expense related to the 2024 Notes and 2026 Notes (in thousands):

	Three Months Ended October 31,								Nine Months Ended October 31,
	2020				2019				2020				2019
	2024 Notes		2026 Notes		2024 Notes		2026 Notes		2024 Notes		2026 Notes		2024 Notes		2026 Notes
Contractual interest expense	$	168	$	718	$	563	$	—	$	506	$	2,156	$	1,688	$	—
Amortization of debt discount	1,002		10,826		3,132		—		2,958		32,058		9,248		—
Amortization of issuance costs	70		469		202		—		203		1,366		585		—
Total	$	1,240	$	12,013	$	3,897	$	—	$	3,667	$	35,580	$	11,521	$	—