Convertible Senior Notes (Tables)

3 Months Ended

Apr. 30, 2018

Debt Disclosure [Abstract]

Convertible Debt

The Notes consisted of the following (in thousands):

	As of April 30, 2018
Liability:
Principal	$	575,000
Less: debt discount, net of amortization	(134,976		)
Less: debt issuance costs, net of amortization	(9,772		)
Net carrying amount of the Notes	$	430,252
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 months ended April 30, 2018 (in thousands):

	Three Months Ended April 30, 2018
Amortization of debt discount	$	1,357
Amortization of debt issuance costs	98
Total amortization of debt discount and debt issuance costs	1,455
Contractual interest expense	43
Total interest expense related to the Notes	$	1,498
Effective interest rate of the liability component	5.6		%