Convertible Senior Notes (Tables)

9 Months Ended

Oct. 31, 2018

Debt Disclosure [Abstract]

Convertible Debt

The Notes consisted of the following (in thousands):

	As of October 31, 2018
Liability:
Principal	$	575,000
Less: debt discount, net of amortization	(122,891		)
Less: debt issuance costs, net of amortization	(8,897		)
Net carrying amount of the Notes	$	443,212
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 the three and nine months ended October 31, 2018 (in thousands):

	Three Months Ended October 31, 2018			Nine Months Ended October 31, 2018
Amortization of debt discount	$	6,084		$	13,441
Amortization of debt issuance costs	441			973
Total amortization of debt discount and debt issuance costs	6,525			14,414
Contractual interest expense	181			405
Total interest expense related to the Notes	$	6,706		$	14,819
Effective interest rate of the liability component	5.6		%	5.6		%