Income Taxes	9 Months Ended
Sep. 27, 2019
Income Tax Disclosure [Abstract]
Income Taxes	13. Income Taxes The Company determines its estimated annual effective tax rate at the end of each interim period based on full-year forecasted pre-tax income and facts known at that time. The estimated annual effective tax rate is applied to the year-to-date pre-tax income at the end of each interim period with the cumulative effect of any changes in the estimated annual effective tax rate being recorded in the fiscal quarter in which the change is determined. The tax effect of significant unusual items is reflected in the period in which they occur. Since the Company is incorporated in Canada, it is required to use Canada’s statutory tax rate of 29.0% in the determination of the estimated annual effective tax rate. The Company’s effective tax rate of 18.8% for the three months ended September 27, 2019 differs from the Canadian statutory tax rate of 29.0% primarily due to the mix of income earned in jurisdictions with varying tax rates, estimated deductions for Foreign Derived Intangible Income, U.K. patent box deductions and other tax credits. The Company’s effective tax rate of 12.9% for the nine months ended September 27, 2019 differs from the Canadian statutory tax rate of 29.0% primarily due to the mix of income earned in jurisdictions with varying tax rates, estimated deductions for Foreign Derived Intangible Income, U.K. patent box deductions, other tax credits, and windfall tax benefits upon vesting of certain share-based compensation awards during the period. The Company’s effective tax rate of 19.5% for the three months ended September 28, 2018 differs from the Canadian statutory tax rate of 29.0% primarily due to the mix of income earned in jurisdictions with varying tax rates, estimated deductions for Foreign Derived Intangible Income, U.K. patent box deductions and other tax credits; offset by non-deductible expenses recognized under an earn-out agreement in connection with the Company’s acquisition of Zettlex Holdings Limited (“Zettlex”) in 2018. The Company’s effective tax rate of 17.3% for the nine months ended September 28, 2018 differs from the Canadian statutory tax rate of 29.0% primarily due to the mix of income earned in jurisdictions with varying tax rates, estimated deductions for Foreign Derived Intangible Income, U.K. patent box deductions, other tax credits, and windfall tax benefits upon vesting of certain share-based compensation awards during the period; offset by non-deductible expenses recognized under an earn-out agreement in connection with the Zettlex acquisition. The Company maintains a valuation allowance on some of its deferred tax assets in certain jurisdictions. A valuation allowance is required when, based upon an assessment of various factors, including recent operating loss history, anticipated future earnings, and prudent and reasonable tax planning strategies, it is more likely than not that some portion of the deferred tax assets will not be realized.

Income Taxes

9 Months Ended

Sep. 27, 2019

13. Income Taxes

The Company determines its estimated annual effective tax rate at the end of each interim period based on full-year forecasted pre-tax income and facts known at that time. The estimated annual effective tax rate is applied to the year-to-date pre-tax income at the end of each interim period with the cumulative effect of any changes in the estimated annual effective tax rate being recorded in the fiscal quarter in which the change is determined. The tax effect of significant unusual items is reflected in the period in which they occur. Since the Company is incorporated in Canada, it is required to use Canada’s statutory tax rate of 29.0% in the determination of the estimated annual effective tax rate.

The Company’s effective tax rate of 18.8% for the three months ended September 27, 2019 differs from the Canadian statutory tax rate of 29.0% primarily due to the mix of income earned in jurisdictions with varying tax rates, estimated deductions for Foreign Derived Intangible Income, U.K. patent box deductions and other tax credits.

The Company’s effective tax rate of 12.9% for the nine months ended September 27, 2019 differs from the Canadian statutory tax rate of 29.0% primarily due to the mix of income earned in jurisdictions with varying tax rates, estimated deductions for Foreign Derived Intangible Income, U.K. patent box deductions, other tax credits, and windfall tax benefits upon vesting of certain share-based compensation awards during the period.

The Company’s effective tax rate of 19.5% for the three months ended September 28, 2018 differs from the Canadian statutory tax rate of 29.0% primarily due to the mix of income earned in jurisdictions with varying tax rates, estimated deductions for Foreign Derived Intangible Income, U.K. patent box deductions and other tax credits; offset by non-deductible expenses recognized under an earn-out agreement in connection with the Company’s acquisition of Zettlex Holdings Limited (“Zettlex”) in 2018.

The Company’s effective tax rate of 17.3% for the nine months ended September 28, 2018 differs from the Canadian statutory tax rate of 29.0% primarily due to the mix of income earned in jurisdictions with varying tax rates, estimated deductions for Foreign Derived Intangible Income, U.K. patent box deductions, other tax credits, and windfall tax benefits upon vesting of certain share-based compensation awards during the period; offset by non-deductible expenses recognized under an earn-out agreement in connection with the Zettlex acquisition.

The Company maintains a valuation allowance on some of its deferred tax assets in certain jurisdictions. A valuation allowance is required when, based upon an assessment of various factors, including recent operating loss history, anticipated future earnings, and prudent and reasonable tax planning strategies, it is more likely than not that some portion of the deferred tax assets will not be realized.