Convertible Senior Notes (Tables)

9 Months Ended

Oct. 31, 2020

Debt Disclosure [Abstract]

Convertible Senior Notes

The net carrying amounts of the liability component for each series of Notes as of October 31, 2020 were as follows:

(In thousands)	2023 Notes (1)		2025 Notes		2027 Notes
Liability component:
Principal amount	$	776,661	$	862,500	$	1,265,000
Unamortized discount	(99,870)		(175,741)		(331,022)
Unamortized issuance costs	(3,897)		(4,835)		(13,483)
Net carrying amount	$	672,894	$	681,924	$	920,495

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(1)    Reflects the impact of the 2023 Notes Partial Repurchase on June 5, 2020, as discussed below.

The net carrying amount of the liability component of the 2023 Notes immediately prior to the repurchase was as follows:

	June 5, 2020
(In thousands)	2023 Notes Total		2023 Notes Partial Repurchase
Principal	$	1,265,000	$	488,339
Unamortized debt discount	(184,336)		(71,161)
Unamortized debt issuance costs	(7,194)		(2,777)
Net carrying amount	$	1,073,470	$	414,401

Schedule of Interest Expense

The following tables sets forth the interest expense related to each series of Notes:

	Three Months Ended October 31,				Nine Months Ended October 31,
(In thousands)	2020		2019		2020		2019
2023 Notes:
Coupon interest expense	$	971	$	1,581	$	3,726	$	4,743
Amortization of debt discount (conversion option)	8,040		12,390		30,062		36,203
Amortization of debt issuance costs	315		484		1,174		1,414
Total interest expense related to the 2023 Notes	$	9,326	$	14,455	$	34,962	$	42,360
2025 Notes:
Coupon interest expense	$	2,426	$	2,426	$	7,278	$	7,278
Amortization of debt discount (conversion option)	7,767		7,308		22,728		21,276
Amortization of debt issuance costs	213		201		624		585
Total interest expense related to the 2025 Notes	$	10,406	$	9,935	$	30,630	$	29,139
2027 Notes:
Coupon interest expense	$	3,558	$	—	$	5,732	$	—
Amortization of debt discount (conversion option)	10,168		—		16,398		—
Amortization of debt issuance costs	414		—		668		—
Total interest expense related to the 2027 Notes	$	14,140	$	—	$	22,798	$	—

Calculation of Gain on Extinguishment of Convertible Senior Notes

The 2023 Notes Partial Repurchase resulted in a gain on extinguishment of convertible senior notes, which was calculated as follows:

(In thousands)	2023 Notes Partial Repurchase
Net carrying amount of the liability component associated with the 2023 Notes Partial Repurchase	$	414,401
Less: Cash consideration allocated to the liability component	(407,449)
Gain from the 2023 Notes Partial Repurchase	$	6,952

Other Key Terms and Premiums Paid for Capped Calls

The following table sets forth other key terms and premiums paid for the Capped Calls related to each series of the Notes:

	Capped Calls Entered into in Connection with the Issuance of the 2023 and 2025 Notes		Capped Calls Entered into in Connection with the Issuance of the 2027 Notes
Initial strike price, subject to certain adjustments	$	148.30	$	255.34
Cap price, subject to certain adjustments	$	232.62	$	378.28
Total premium paid (in thousands)	$	274,275	$	137,379