Net Income (Loss) per Ordinary Share

6 Months Ended

Jun. 30, 2020

Basic net income (loss) per ordinary share is based on the weighted-average number of ordinary shares outstanding. Diluted net income (loss) per ordinary share is based on the weighted-average number of ordinary shares outstanding and potentially dilutive ordinary shares outstanding.

Basic and diluted net income (loss) per ordinary share were computed as follows (in thousands, except per share amounts):



	Three Months Ended June 30,				Six Months Ended June 30,
	2020		2019		2020			2019
Numerator:
Net income (loss)	$	114,801	$	261,898	$	(43,032	)	$	347,099
Denominator:
Weighted-average ordinary shares used in per share calculations - basic	55,413		56,707		55,684			56,955
Dilutive effect of employee equity incentive and purchase plans	451		720		—			798
Weighted-average ordinary shares used in per share calculations - diluted	55,864		57,427		55,684			57,753

Net income (loss) per ordinary share:
Basic	$	2.07	$	4.62	$	(0.77	)	$	6.09
Diluted	$	2.06	$	4.56	$	(0.77	)	$	6.01

Potentially dilutive ordinary shares from our employee equity incentive and purchase plans and the Exchangeable Senior Notes are determined by applying the treasury stock method to the assumed exercise of share options, the assumed vesting of outstanding restricted stock units, or RSUs, the assumed issuance of ordinary shares under our employee stock purchase plan, or ESPP, and the assumed issuance of ordinary shares upon exchange of the Exchangeable Senior Notes. The potential issue of ordinary shares issuable upon exchange of the Exchangeable Senior Notes had no effect on diluted net income (loss) per ordinary share because the average price of our ordinary shares for the three and six months ended June 30, 2020 and 2019 did not exceed the effective exchange prices per ordinary share of the Exchangeable Senior Notes.

The following table represents the weighted-average ordinary shares that were excluded from the calculation of diluted net income (loss) per ordinary share for the periods presented because including them would have an anti-dilutive effect (in thousands):



	Three Months Ended June 30,		Six Months Ended June 30,
	2020	2019	2020	2019
Exchangeable Senior Notes	6,474	5,504	5,989	5,504
Options, RSUs and ESPP	6,178	5,202	5,895	5,095