Income Taxes	6 Months Ended
Income Taxes	Sep. 30, 2019
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 benefit for the three months ended September 30, 2019 was $2.6 million based on an effective income tax rate of (3.7)% of pre-tax income, compared to an income tax provision of $6.2 million based on an effective income tax rate of 8.8% of pre-tax income for the three months ended September 30, 2018. The income tax provision for the six months ended September 30, 2019 was $3.9 million based on an effective income tax rate of 3.2% of pre-tax income, compared to an income tax provision of $1.0 million based on an effective income tax rate of 1.0% of pre-tax income for the six months ended September 30, 2018. On May 19, 2019, the Swiss electorate approved the Federal Act on Tax Reform and AHV Financing ("TRAF"), a major reform to better align the Swiss tax system with international tax standards. The legislation was subsequently published in the federal register on August 6, 2019 to take effect on January 1, 2020. As of September 30, 2019, TRAF has not been enacted in all cantons, including the canton of Vaud, as the cantonal legislative procedures are in process. The change in the effective income tax rate for the three months ended September 30, 2019, compared to the same period ended September 30, 2018, was primarily due to the transitional income tax impact in Switzerland. The Company has benefited from a longstanding tax ruling from the canton of Vaud through March 31, 2019. During the second quarter, the canton of Vaud concluded the longstanding cantonal tax ruling will only continue to apply through December 31, 2019. The transitional income tax impact, which represents income tax provision at the current full statutory income tax rate of 13.63% without taking account of the tax reform yet to be enacted, resulted in a tax benefit of $5.9 million in the three-month period 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, 2019, compared to the same period ended September 30, 2018 was primarily due to the mix of income and losses in the various tax jurisdictions in which the Company operates and the transitional income tax impact in Switzerland discussed 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 $6.7 million and $1.8 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, 2019, compared with $9.0 million and $1.4 million, respectively, in the six-month period ended September 30, 2018. As of September 30, 2019 and March 31, 2019, the total amount of unrecognized tax benefits due to uncertain tax positions was $78.9 million and $76.5 million, respectively, all of which would affect the effective income tax rate if recognized. As of September 30, 2019 and March 31, 2019, the Company had $36.4 million 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 income tax provision. As of September 30, 2019 and March 31, 2019, the Company had $2.8 million and $2.5 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 2020, 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 $3.7 million from the lapse of the statutes of limitations in various jurisdictions during the next twelve months.