Income Taxes	6 Months Ended
Jun. 30, 2019
Income Taxes [Abstract]
Income Taxes	6. Income Taxes Income Tax Expense Our effective income tax rate was a benefit of 3% and 133% for the three and six months ended June 30, 2019, respectively, as compared to a benefit of 269% and 48% for the three and six months ended June 30, 2018, respectively. The change in the tax rate for the three and six months ended June 30, 2019 is primarily due to a change in pre-tax book income for the three and six months ended June 30, 2019 as compared to the three and six months ended June 30, 2018. The income tax rate for the three and six months ended June 30, 2019 was impacted by excess tax benefit deductions related to stock compensation, which increased income tax benefits by approximately $700,000 and $1.9 million, respectively. The income tax rate was also favorably impacted by losses in high rate jurisdictions, partially offset by unfavorable impacts of non-deductible operating expenses and executive compensation expenses. The income tax rate for the three and six months ended June 30, 2018 was impacted by excess tax benefit deductions related to stock compensation, which increased income tax benefits by approximately $300,000 and $1.4 million, respectively, and losses in high rate jurisdictions. These factors were partially offset by impacts of non-deductible operating expenses and executive compensation expenses. Deferred Income Taxes We generate deferred tax assets primarily as a result of write-downs of inventory and deferred preservation costs, accruals for product and tissue processing liability claims, investment and asset impairments, and operating losses. We acquired significant deferred tax assets, primarily net operating loss carryforwards, from our acquisitions of JOTEC GmbH (“JOTEC”) and its subsidiaries in 2017, On-X in 2016, Hemosphere, Inc. in 2012, and Cardiogenesis Corporation in 2011. We believe utilization of these net operating losses will not have a material impact on income taxes for the 2019 tax year. As of June 30, 2019 we maintained a total of $3.9 million in valuation allowances against deferred tax assets, primarily related to state net operating loss carryforwards, and had a net deferred tax liability of $22.7 million. As of December 31, 2018 we had a total of $3.4 million in valuation allowances against deferred tax assets, primarily related to state net operating loss carryforwards, and a net deferred tax liability of $23.2 million.

Income Taxes

6 Months Ended

Jun. 30, 2019

6. Income Taxes

Income Tax Expense

Our effective income tax rate was a benefit of 3% and 133% for the three and six months ended June 30, 2019, respectively, as compared to a benefit of 269% and 48% for the three and six months ended June 30, 2018, respectively. The change in the tax rate for the three and six months ended June 30, 2019 is primarily due to a change in pre-tax book income for the three and six months ended June 30, 2019 as compared to the three and six months ended June 30, 2018.

The income tax rate for the three and six months ended June 30, 2019 was impacted by excess tax benefit deductions related to stock compensation, which increased income tax benefits by approximately $700,000 and $1.9 million, respectively. The income tax rate was also favorably impacted by losses in high rate jurisdictions, partially offset by unfavorable impacts of non-deductible operating expenses and executive compensation expenses.

The income tax rate for the three and six months ended June 30, 2018 was impacted by excess tax benefit deductions related to stock compensation, which increased income tax benefits by approximately $300,000 and $1.4 million, respectively, and losses in high rate jurisdictions. These factors were partially offset by impacts of non-deductible operating expenses and executive compensation expenses.

Deferred Income Taxes

We generate deferred tax assets primarily as a result of write-downs of inventory and deferred preservation costs, accruals for product and tissue processing liability claims, investment and asset impairments, and operating losses. We acquired significant deferred tax assets, primarily net operating loss carryforwards, from our acquisitions of JOTEC GmbH (“JOTEC”) and its subsidiaries in 2017, On-X in 2016, Hemosphere, Inc. in 2012, and Cardiogenesis Corporation in 2011. We believe utilization of these net operating losses will not have a material impact on income taxes for the 2019 tax year.

As of June 30, 2019 we maintained a total of $3.9 million in valuation allowances against deferred tax assets, primarily related to state net operating loss carryforwards, and had a net deferred tax liability of $22.7 million. As of December 31, 2018 we had a total of $3.4 million in valuation allowances against deferred tax assets, primarily related to state net operating loss carryforwards, and a net deferred tax liability of $23.2 million.