Calculation of Earnings per Share

The following table presents the computation of weighted-average shares used in the calculation of basic and diluted earnings per share:



	Three Months Ended September 30,		Nine Months Ended September 30,
	2018	2017	2018	2017
	(In thousands)
Weighted-average shares of common stock outstanding	121,682	99,614	111,046	101,036
Weighted-average potential shares of common stock outstanding:
Conversion spread related to Subordinated Convertible Debentures	—	23,956	11,452	22,605
Unvested RSUs and ESPP	579	504	581	521
Shares used to compute diluted earnings per share	122,261	124,074	123,079	124,162

The weighted average shares of common stock outstanding for the three and nine months ended September 30, 2018, reflects the issuance of 26.1 million shares of common stock related to the settlement of the Subordinated Convertible Debentures on May 1, 2018. The dilutive impact of the conversion spread related to the Subordinated Convertible Debentures is included in the calculation for the nine months ended September 30, 2018, on a weighted-average basis for the period prior to conversion.

The calculation of diluted weighted average shares outstanding, excludes potentially dilutive securities, the effect of which would have been anti-dilutive, as well as performance-based RSUs granted by the Company for which the relevant performance criteria have not been achieved. The number of potential shares excluded from the calculation was not significant in any period presented.