Convertible Senior Notes - (Tables)

9 Months Ended

Oct. 31, 2019

Debt Disclosure [Abstract]

Convertible Debt

The Notes consisted of the following (in thousands):

	As of October 31, 2019
Liability:
Principal	$	575,000
Less: debt discount, net of amortization	(97,898)
Less: debt issuance costs, net of amortization	(7,088)
Net carrying amount of the Notes	$	470,014
Stockholders' equity:
Allocated value of the conversion feature	$	136,333
Less: debt issuance costs	(3,068)
Additional paid-in capital	$	133,265

Interest Expense

The following table sets forth total interest expense recognized related to the Notes for three and nine months ended October 31, 2018 and 2019 (in thousands):

	Three Months Ended October 31,						Nine Months Ended October 31,
	2018			2019			2018			2019
Amortization of debt discount	$	6,084		$	6,431		$	13,441		$	18,824
Amortization of debt issuance costs	441			465			973			1,362
Total amortization of debt discount and debt issuance costs	6,525			6,896			14,414			20,186
Contractual interest expense	181			181			405			539
Total interest expense related to the Notes	$	6,706		$	7,077		$	14,819		$	20,725
Effective interest rate of the liability component	5.6		%	5.6		%	5.6		%	5.6		%