Income Taxes	6 Months Ended
Mar. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	13. Income Taxes The Coronavirus Aid, Relief and Economic Security Act (the “CARES Act”), enacted on March 27, 2020, includes significant business tax provisions. In particular, the CARES Act modified the rules associated with net operating losses (“NOLs”) and made technical corrections to tax depreciation methods for qualified improvement property. Under the temporary provisions of CARES Act, NOL carryforwards and carrybacks may offset 100% of taxable income for taxable years beginning before 2021. In addition, NOLs arising in 2018, 2019 and 2020 taxable years may be carried back to each of the preceding five years to generate a refund. The Company recorded an income tax benefit of $1.9 million and $0.2 million for the three months ended March 31, 2020 and 2019, respectively, and $2.2 million and $0.3 million for the six months ended March 31, 2020 and 2019, respectively. In the three and six months ended March 31, 2020, the income tax benefit includes a discrete tax benefit of $1.8 million as result of our ability under the CARES Act to carry back NOLs incurred to periods when the statutory tax rate was 35% versus our current tax rate of 21%. The effective income tax rate for the three and six months ended March 31, 2020 and 2019 differs from the U.S. federal statutory tax rate of 21% primarily due to the discrete tax benefits recognized under the CARES Act, favorable impacts of the U.S. federal research and development tax credits in both periods, stock award activity in the six-month period, and operating results of our Irish subsidiary, where tax benefit is offset by a valuation allowance. The Company recognized discrete tax benefits related to stock-based compensation awards vested, expired, cancelled and exercised of less than $0.1 million in each of three months ended March 31, 2020 and 2019 and $0.3 million and $0.5 million in the six months ended March 31, 2020 and 2019, respectively. The total amount of unrecognized tax benefits, excluding interest and penalties that, if recognized, would affect the effective tax rate is $2.7 million and $2.1 million as of March 31, 2020 and September 30, 2019, respectively. Interest and penalties related to unrecognized tax benefits are recorded in the income tax benefit. For interim income tax reporting, the Company estimates its annual effective tax rate and applies it to year-to-date pretax (loss) income, excluding unusual or infrequently occurring discrete items. Tax jurisdictions with losses for which tax benefits cannot be realized are excluded. The Company files income tax returns, including returns for its subsidiaries, in the U.S. federal jurisdiction and in various state jurisdictions as well as several non-U.S. jurisdictions. Uncertain tax positions are related to tax years that remain subject to examination. U.S. income tax returns for years prior to fiscal 2016 are no longer subject to examination by federal tax authorities. For tax returns for state and local jurisdictions, the Company is no longer subject to examination for tax years generally before fiscal 2009. For tax returns for non-U.S. jurisdictions, the Company is no longer subject to income tax examination for years prior to 2014. Additionally, the Company has been indemnified of liability for any taxes relating to Creagh Medical and NorMedix for periods prior to their respective acquisition dates, pursuant to the terms of the related share purchase agreements. There were no undistributed earnings in foreign subsidiaries as of March 31, 2020 and September 30, 2019.

Income Taxes

6 Months Ended

Mar. 31, 2020

13. Income Taxes

The Coronavirus Aid, Relief and Economic Security Act (the “CARES Act”), enacted on March 27, 2020, includes significant business tax provisions. In particular, the CARES Act modified the rules associated with net operating losses (“NOLs”) and made technical corrections to tax depreciation methods for qualified improvement property. Under the temporary provisions of CARES Act, NOL carryforwards and carrybacks may offset 100% of taxable income for taxable years beginning before 2021. In addition, NOLs arising in 2018, 2019 and 2020 taxable years may be carried back to each of the preceding five years to generate a refund.

The Company recorded an income tax benefit of $1.9 million and $0.2 million for the three months ended March 31, 2020 and 2019, respectively, and $2.2 million and $0.3 million for the six months ended March 31, 2020 and 2019, respectively. In the three and six months ended March 31, 2020, the income tax benefit includes a discrete tax benefit of $1.8 million as result of our ability under the CARES Act to carry back NOLs incurred to periods when the statutory tax rate was 35% versus our current tax rate of 21%.

The effective income tax rate for the three and six months ended March 31, 2020 and 2019 differs from the U.S. federal statutory tax rate of 21% primarily due to the discrete tax benefits recognized under the CARES Act, favorable impacts of the U.S. federal research and development tax credits in both periods, stock award activity in the six-month period, and operating results of our Irish subsidiary, where tax benefit is offset by a valuation allowance. The Company recognized discrete tax benefits related to stock-based compensation awards vested, expired, cancelled and exercised of less than $0.1 million in each of three months ended March 31, 2020 and 2019 and $0.3 million and $0.5 million in the six months ended March 31, 2020 and 2019, respectively.

The total amount of unrecognized tax benefits, excluding interest and penalties that, if recognized, would affect the effective tax rate is $2.7 million and $2.1 million as of March 31, 2020 and September 30, 2019, respectively. Interest and penalties related to unrecognized tax benefits are recorded in the income tax benefit.

For interim income tax reporting, the Company estimates its annual effective tax rate and applies it to year-to-date pretax (loss) income, excluding unusual or infrequently occurring discrete items. Tax jurisdictions with losses for which tax benefits cannot be realized are excluded. The Company files income tax returns, including returns for its subsidiaries, in the U.S. federal jurisdiction and in various state jurisdictions as well as several non-U.S. jurisdictions. Uncertain tax positions are related to tax years that remain subject to examination. U.S. income tax returns for years prior to fiscal 2016 are no longer subject to examination by federal tax authorities. For tax returns for state and local jurisdictions, the Company is no longer subject to examination for tax years generally before fiscal 2009. For tax returns for non-U.S. jurisdictions, the Company is no longer subject to income tax examination for years prior to 2014. Additionally, the Company has been indemnified of liability for any taxes relating to Creagh Medical and NorMedix for periods prior to their respective acquisition dates, pursuant to the terms of the related share purchase agreements. There were no undistributed earnings in foreign subsidiaries as of March 31, 2020 and September 30, 2019.