Retirement Benefit Plans

12 Months Ended

Dec. 31, 2019

Retirement Benefits [Abstract]

Pension and Other Postretirement Benefits Disclosure [Text Block]

8. Retirement Benefit Plans

The Company has a defined contribution retirement plan that covers its eligible employees (the “Plan”). The Plan is qualified in accordance with Section 401(k) of the Internal Revenue Code of 1986, as amended (the “Code”). Eligible employees can participate in the Company’s pre-tax 401(k) plan or after-tax Roth 401(k) plan. The Company makes matching contributions equal to 100% of the first 3% of compensation deferred by a participant. Beginning in January 2019, the Company also makes matching contributions equal to 50% of the next 2% of compensation deferred by a participant. The Company may make an additional discretionary matching contribution. The Company recognized expense related to its contributions to the Plan of $2.0 million, $1.5 million, and $1.3 million during the years ended December 31, 2019, 2018, and 2017, respectively.