Income Taxes	9 Months Ended
Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company is incorporated in Switzerland but operates in various countries with differing tax laws and rates. Further, a portion of the Company’s income before taxes and the provision for (benefit from) income taxes are generated outside of Switzerland. The income tax provision for the three months ended December 31, 2017 was $20.0 million based on an effective income tax rate of 19.9% of pre-tax income, compared to an income tax provision of $1.6 million based on an effective income tax rate of 1.7% of pre-tax income for the three months ended December 31, 2016. The income tax provision for the nine months ended December 31, 2017 was $18.7 million based on an effective income tax rate of 9.7% of pre-tax income, compared to an income tax provision of $10.3 million based on an effective income tax rate of 5.8% for the nine months ended December 31, 2016. On December 22, 2017, the Tax Act was signed into law in the United States. The Tax Act introduced a broad range of tax reform measures that significantly change the federal income tax regime. Among other things, the Tax Act permanently reduces the corporate income tax rate from 35% to 21% effective for tax years including or commencing on January 1, 2018, repeals corporate alternative minimum tax, limits various business deductions, modifies the maximum deduction of net operating loss with no carryback but indefinite carryforward provision and includes various international tax provisions. Many provisions in the Tax Act are generally effective in tax years beginning after December 31, 2017. ASC 740 requires recognition of the effects of tax law changes in the period of enactment. Notwithstanding that the effective date of the Tax Act for most provisions is January 1, 2018, such effects must be recognized in December 2017 financial statements. In accordance to the new tax legislation, the Company applied a blended federal income tax rate of 31.6% to its operations in the United States effective at the beginning of the fiscal year based on a pro-rated percentage of the number of days before and after January 1, 2018. Furthermore, the Company recorded an income tax charge of $19.9 million from the estimated remeasurement of federal deferred tax assets and liabilities as of December 31, 2017 to reflect the effects of the enacted changes in tax rate and an income tax benefit of $4.1 million from assessment of valuation allowance against tax credits due to changes in tax laws. These amounts account for the change in the effective income tax rate in the three months ended December 31, 2017 compared to the same period of the prior fiscal year. The estimated remeasurement of deferred tax assets and liabilities was based on tax rates generally at 31.6% and 21% depending on the timing of when the individual deferred tax assets and liabilities are expected to recover or settle in the future. The net provisional charge from deferred tax remeasurement and assessment of valuation allowance is based on currently available information and interpretations which are continuing to evolve. The Company continues to analyze additional information and guidance related to certain aspects of the Tax Act, such as limitations on the deductibility of executive compensation, conformity or changes by state taxing authorities in response to the Tax Act, and the final determination of the net deferred tax assets subject to the remeasurement and related impacts to the assessment of valuation allowance. The prospects of supplemental legislation or regulatory processes to address questions that arise because of the Tax Act, or evolving technical interpretations of the tax law, may cause the final impact from the Tax Act to differ from the recorded amounts. The Company continues to appropriately refine such amounts within the measurement period allowed by Staff Accounting Bulletin (“SAB”) No.118, which will be completed no later than the third quarter of fiscal year 2019. The change in the effective income tax rate in the nine months ended December 31, 2017 compared to the same period of the prior fiscal year is primarily due to the recognition of excess tax benefits of $10.8 million after adoption of ASU 2016-09 and income tax benefit from the reversal of uncertain tax positions from the expiration of statutes of limitations are largely offset by income tax provision from the remeasurement of deferred tax assets and liabilities in the third quarter. In the three and nine months ended December 31, 2017, there was a discrete income tax benefit of $6.0 million and $7.9 million, respectively, from the reversal of uncertain tax positions from the expiration of statutes of limitations. In the same periods ended December 31, 2016, the income tax benefit from the reversal of uncertain tax positions from the expiration of statutes of limitations was $9.4 million and $11.1 million, respectively. As of December 31 and March 31, 2017, the total amount of unrecognized tax benefits due to uncertain tax positions was $67.3 million and $63.7 million, respectively, all of which would affect the effective income tax rate if recognized. The Company had $34.4 million in non-current income taxes payable and $0.1 million in current income taxes payable, including interest and penalties, related to its income tax liability for uncertain tax positions as of December 31, 2017, compared to $51.8 million in non-current income taxes payable and $1.5 million in current income taxes payable as of March 31, 2017. The Company applied to a settlement program and paid $1.9 million to the tax authorities in a foreign jurisdiction in the third quarter of fiscal year 2018. The Company recognizes interest and penalties related to unrecognized tax positions in income tax expense. As of December 31 and March 31, 2017, the Company had $2.1 million and $3.0 million, respectively, of accrued interest and penalties related to uncertain tax positions. Although the Company has adequately provided for uncertain tax positions, the provisions on these positions may change as revised estimates are made or the underlying matters are settled or otherwise resolved. During fiscal year 2018, the Company continues to review its tax positions and provide for or reverse unrecognized tax benefits as issues arise. During the next twelve months, it is reasonably possible that the amount of unrecognized tax benefits could increase or decrease significantly due to changes in tax law in various jurisdictions, new tax audits and changes in the U.S. dollar as compared to other currencies. Excluding these factors, uncertain tax positions may decrease by as much as $21.4 million from the lapse of the statutes of limitations in various jurisdictions during the next twelve months.

Income Taxes

The Company is incorporated in Switzerland but operates in various countries with differing tax laws and rates. Further, a portion of the Company’s income before taxes and the provision for (benefit from) income taxes are generated outside of Switzerland.

The income tax provision for the three months ended December 31, 2017 was $20.0 million based on an effective income tax rate of 19.9% of pre-tax income, compared to an income tax provision of $1.6 million based on an effective income tax rate of 1.7% of pre-tax income for the three months ended December 31, 2016. The income tax provision for the nine months ended December 31, 2017 was $18.7 million based on an effective income tax rate of 9.7% of pre-tax income, compared to an income tax provision of $10.3 million based on an effective income tax rate of 5.8% for the nine months ended December 31, 2016.

On December 22, 2017, the Tax Act was signed into law in the United States. The Tax Act introduced a broad range of tax reform measures that significantly change the federal income tax regime. Among other things, the Tax Act permanently reduces the corporate income tax rate from 35% to 21% effective for tax years including or commencing on January 1, 2018, repeals corporate alternative minimum tax, limits various business deductions, modifies the maximum deduction of net operating loss with no carryback but indefinite carryforward provision and includes various international tax provisions. Many provisions in the Tax Act are generally effective in tax years beginning after December 31, 2017.

ASC 740 requires recognition of the effects of tax law changes in the period of enactment. Notwithstanding that the effective date of the Tax Act for most provisions is January 1, 2018, such effects must be recognized in December 2017 financial statements. In accordance to the new tax legislation, the Company applied a blended federal income tax rate of 31.6% to its operations in the United States effective at the beginning of the fiscal year based on a pro-rated percentage of the number of days before and after January 1, 2018. Furthermore, the Company recorded an income tax charge of $19.9 million from the estimated remeasurement of federal deferred tax assets and liabilities as of December 31, 2017 to reflect the effects of the enacted changes in tax rate and an income tax benefit of $4.1 million from assessment of valuation allowance against tax credits due to changes in tax laws. These amounts account for the change in the effective income tax rate in the three months ended December 31, 2017 compared to the same period of the prior fiscal year.

The estimated remeasurement of deferred tax assets and liabilities was based on tax rates generally at 31.6% and 21% depending on the timing of when the individual deferred tax assets and liabilities are expected to recover or settle in the future. The net provisional charge from deferred tax remeasurement and assessment of valuation allowance is based on currently available information and interpretations which are continuing to evolve. The Company continues to analyze additional information and guidance related to certain aspects of the Tax Act, such as limitations on the deductibility of executive compensation, conformity or changes by state taxing authorities in response to the Tax Act, and the final determination of the net deferred tax assets subject to the remeasurement and related impacts to the assessment of valuation allowance. The prospects of supplemental legislation or regulatory processes to address questions that arise because of the Tax Act, or evolving technical interpretations of the tax law, may cause the final impact from the Tax Act to differ from the recorded amounts. The Company continues to appropriately refine such amounts within the measurement period allowed by Staff Accounting Bulletin (“SAB”) No.118, which will be completed no later than the third quarter of fiscal year 2019.

The change in the effective income tax rate in the nine months ended December 31, 2017 compared to the same period of the prior fiscal year is primarily due to the recognition of excess tax benefits of $10.8 million after adoption of ASU 2016-09 and income tax benefit from the reversal of uncertain tax positions from the expiration of statutes of limitations are largely offset by income tax provision from the remeasurement of deferred tax assets and liabilities in the third quarter. In the three and nine months ended December 31, 2017, there was a discrete income tax benefit of $6.0 million and $7.9 million, respectively, from the reversal of uncertain tax positions from the expiration of statutes of limitations. In the same periods ended December 31, 2016, the income tax benefit from the reversal of uncertain tax positions from the expiration of statutes of limitations was $9.4 million and $11.1 million, respectively.

As of December 31 and March 31, 2017, the total amount of unrecognized tax benefits due to uncertain tax positions was $67.3 million and $63.7 million, respectively, all of which would affect the effective income tax rate if recognized.

The Company had $34.4 million in non-current income taxes payable and $0.1 million in current income taxes payable, including interest and penalties, related to its income tax liability for uncertain tax positions as of December 31, 2017, compared to $51.8 million in non-current income taxes payable and $1.5 million in current income taxes payable as of March 31, 2017. The Company applied to a settlement program and paid $1.9 million to the tax authorities in a foreign jurisdiction in the third quarter of fiscal year 2018.

The Company recognizes interest and penalties related to unrecognized tax positions in income tax expense. As of December 31 and March 31, 2017, the Company had $2.1 million and $3.0 million, respectively, of accrued interest and penalties related to uncertain tax positions.

Although the Company has adequately provided for uncertain tax positions, the provisions on these positions may change as revised estimates are made or the underlying matters are settled or otherwise resolved. During fiscal year 2018, the Company continues to review its tax positions and provide for or reverse unrecognized tax benefits as issues arise. During the next twelve months, it is reasonably possible that the amount of unrecognized tax benefits could increase or decrease significantly due to changes in tax law in various jurisdictions, new tax audits and changes in the U.S. dollar as compared to other currencies. Excluding these factors, uncertain tax positions may decrease by as much as $21.4 million from the lapse of the statutes of limitations in various jurisdictions during the next twelve months.