Income Taxes	6 Months Ended
Income Taxes	Sep. 30, 2020
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 canton of Vaud enacted the Federal Act on Tax Reform and AHV Financing ("TRAF"), a major reform to better align the Swiss tax system with international tax standards, on March 10, 2020 to take effect as of January 1, 2020. The longstanding tax ruling from the canton of Vaud was applicable through December 31, 2019. The income tax provision for the three months ended September 30, 2020 was $56.3 million based on an effective income tax rate of 17.4% of pre-tax income, compared to an income tax benefit of $2.6 million based on an effective income tax rate of (3.7)% of pre-tax income for the three months ended September 30, 2019. The income tax provision for the six months ended September 30, 2020 was $70.3 million based on an effective income tax rate of 17.2% of pre-tax income, compared to an income tax provision of $3.9 million based on an effective income tax rate of 3.2% of pre-tax income for the six months ended September 30, 2019. The change in the effective income tax rate for the three months ended September 30, 2020, compared to the same period ended September 30, 2019 was primarily due to the mix of income and losses in the various tax jurisdictions in which the Company operates. The Swiss income tax provision in the three months ended September 30, 2020 represents the income tax provision at the full statutory income tax rate of 13.63%. In the same period ended September 30, 2019 when TRAF was yet to be enacted at the federal and cantonal levels, the transition income tax provision reflects the application of the longstanding tax ruling through December 31, 2019 including a retroactive adjustment made to the preceding three-month period ended June 30, 2019 when the transition income tax provision was quantified at the full statutory income tax rate of 13.63% because at the time the canton of Vaud permitted the application of the longstanding tax ruling only through March 31, 2019. The retroactive adjustment resulted in a tax benefit of $5.9 million in the three months ended September 30, 2019. In addition, there was a discrete tax benefit of $4.0 million from adjusting deferred tax assets and liabilities in Switzerland in the three months ended September 30, 2019. The change in the effective income tax rate for the six months ended September 30, 2020, compared to the same period ended September 30, 2019 was primarily due to the mix of income and losses in the various tax jurisdictions in which the Company operates. The Swiss income tax provision in the six months ended September 30, 2020 represents the income tax provision at the full statutory income tax rate of 13.63%. The income tax provision in the six months ended September 30, 2019 reflects the application of the longstanding tax ruling through December 31, 2019 as stated above. In the six months ended September 30, 2019, there was a discrete tax benefit of $1.7 million from adjusting deferred tax assets and liabilities in Switzerland. Furthermore, there were discrete tax benefits of $5.8 million and $1.5 million from the recognition of excess tax benefits in the United States and reversal of uncertain tax positions from the expiration of statutes of limitations, respectively, in the six-month period ended September 30, 2020, compared with $6.7 million and $1.8 million, respectively, in the six-month period ended September 30, 2019. As of September 30, 2020 and March 31, 2020, the total amount of unrecognized tax benefits due to uncertain tax positions was $152.5 million and $140.8 million, respectively, all of which would affect the effective income tax rate if recognized. As of September 30, 2020 and March 31, 2020, the Company had $54.5 million and $40.8 million, respectively, in non-current income taxes payable including interest and penalties, related to the Company's income tax liability for uncertain tax positions. The Company recognizes interest and penalties related to unrecognized tax positions in the income tax provision. As of September 30, 2020 and March 31, 2020, the Company had $4.8 million and $4.5 million, respectively, of accrued interest and penalties related to uncertain tax positions in non-current income taxes payable. Although the Company has adequately provided for uncertain tax positions, the provisions related to these positions may change as revised estimates are made or the underlying matters are settled or otherwise resolved. During fiscal year 2021, the Company continues to review its tax positions and provide for or reverse unrecognized tax benefits as they 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 $4.7 million from the lapse of the statutes of limitations in various jurisdictions during the next twelve months.

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.