Debt (Tables)

3 Months Ended

Apr. 30, 2016

Debt Disclosure [Abstract]

Summary of Convertible Senior Notes

Convertible Senior Notes

	Par Value Outstanding		Equity Component Recorded at Issuance			Liability Component of Par Value as of
(in thousands)						April 30, 2016			January 31, 2016
0.25% Convertible Senior Notes due April 1, 2018	$	1,150,000	$	122,421	(1)	$	1,095,104	(2)	$	1,088,097	(2)

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(1)This amount represents the equity component recorded at the initial issuance of the 0.25% convertible senior notes.

(2)In April 2015, the FASB issued ASU 2015-03 which simplifies the presentation of debt issuance costs by requiring debt issuance costs to be presented as a deduction from the corresponding debt liability rather than an asset that is amortized. The Company retrospectively adopted this standard for the prior period presented.

Certain terms of the conversion features of the 0.25% Senior Notes are as follows:

	Conversion Rate per $1,000 Par Value	Initial Conversion Price per Share		Convertible Date
0.25% Senior Notes	15.0512	$	66.44	January 1, 2018

Schedule of Convertible Senior Notes

The 0.25% Senior Notes consisted of the following (in thousands):

	As of
	April 30, 2016			January 31, 2016
Liability component :
Principal (1)	$	1,150,000		$	1,150,000
Less: debt discount, net (2)	(48,753		)	(54,941		)
Less: debt issuance cost (3)	(6,143		)	(6,962		)
Net carrying amount	$	1,095,104		$	1,088,097

(1)The effective interest rate of the 0.25% Senior Notes is 2.53%. The interest rate is based on the interest rates of similar liabilities at the time of issuance that did not have an associated convertible feature.

(2)Included in the consolidated balance sheets within Convertible 0.25% Senior Notes (which is classified as a noncurrent liability) and is amortized over the life of the 0.25% Senior Notes using the effective interest rate method.

(3)In April 2015, the FASB issued ASU 2015-03 which simplifies the presentation of debt issuance costs by requiring debt issuance costs to be presented as a deduction from the corresponding debt liability rather than an asset that is amortized. The Company retrospectively adopted this standard for the prior period presented.

Summary of Hedge Notes

To minimize the impact of potential economic dilution upon conversion of the Notes, the Company entered into convertible note hedge transactions with respect to its common stock (the “0.25% Note Hedges”).

(in thousands, except for shares)	Date	Purchase		Shares
0.25% Note Hedges	March 2013	$	153,800	17,308,880

Components of Warrants

Warrants

	Date	Proceeds (in thousands)		Shares	Strike Price
0.25% Warrants	March 2013	$	84,800	17,308,880	$	90.40

Schedule of Interest Expense

The following table sets forth total interest expense recognized related to the 0.25% Senior Notes, the Credit Facility and the Loan prior to capitalization of interest (in thousands):

	Three Months Ended April 30,
	2016		2015
Contractual interest expense	$	2,814	$	3,350
Amortization of debt issuance costs	1,028		1,018
Amortization of debt discount	6,226		6,059
	$	10,068	$	10,427