Transactions With Related Parties	12 Months Ended
Dec. 31, 2018
Transactions With Related Parties [Abstract]
Transactions With Related Parties	18. Transactions with Related Parties A member of our Board of Directors and a shareholder of the Company is an employee of an investment banking services company. On January 20, 2016 we acquired On-X. The investment banking company represented On-X, not us, in that acquisition, for which that investment banking services company earned $3.0 million in fees upon the close of the acquisition. We paid these fees directly to the investment banking company on behalf of On-X from the acquisition sales proceeds otherwise due On-X shareholders. A member of our Board of Directors and a shareholder of the Company, who retired from the Board of Directors during 2018, was the former Chief of Thoracic Surgery of a university hospital that generated product and preservation services revenues of $443,000, $133,000, and $316,000 for us in 2018, 2017, and 2016, respectively. Additionally, the son of this former member of our Board of Directors received a retainer for performing heart and lung transplants from a medical center that generated product and preservation services revenues of $745,000, $793,000, and $479,000 for us in 2018, 2017, and 2016, respectively. A member of our Board of Directors and a shareholder of the Company, who joined our Board of Directors during 2018, is the CEO of a hospital that generated product and preservation services revenues of $296,000 in 2018. We expensed $23,000, $34,000, and $39,000 in 2018, 2017, and 2016, respectively, relating to supplies for clinical trials purchased from a company whose former Chief Financial Officer is a member of the Company's Board of Directors and a shareholder of the Company. We expensed $55,000, $53,000, and $44,000 in 2018, 2017, and 2016, respectively, relating to membership fees to a medical device trade association where our President and CEO is a current member of the Board of Directors.

18. Transactions with Related Parties

A member of our Board of Directors and a shareholder of the Company is an employee of an investment banking services company. On January 20, 2016 we acquired On-X. The investment banking company represented On-X, not us, in that acquisition, for which that investment banking services company earned $3.0 million in fees upon the close of the acquisition. We paid these fees directly to the investment banking company on behalf of On-X from the acquisition sales proceeds otherwise due On-X shareholders.

A member of our Board of Directors and a shareholder of the Company, who retired from the Board of Directors during 2018, was the former Chief of Thoracic Surgery of a university hospital that generated product and preservation services revenues of $443,000, $133,000, and $316,000 for us in 2018, 2017, and 2016, respectively. Additionally, the son of this former member of our Board of Directors received a retainer for performing heart and lung transplants from a medical center that generated product and preservation services revenues of $745,000, $793,000, and $479,000 for us in 2018, 2017, and 2016, respectively.

A member of our Board of Directors and a shareholder of the Company, who joined our Board of Directors during 2018, is the CEO of a hospital that generated product and preservation services revenues of $296,000 in 2018.

We expensed $23,000, $34,000, and $39,000 in 2018, 2017, and 2016, respectively, relating to supplies for clinical trials purchased from a company whose former Chief Financial Officer is a member of the Company's Board of Directors and a shareholder of the Company.

We expensed $55,000, $53,000, and $44,000 in 2018, 2017, and 2016, respectively, relating to membership fees to a medical device trade association where our President and CEO is a current member of the Board of Directors.