Benefit plans	12 Months Ended
Dec. 31, 2019
Benefit plans
Benefit plans	14. Benefit plans The Company established a defined‑contribution savings plan under Section 401(k) of the Code (the “401(k) Plan”). The 401(k) Plan covers all U.S. employees and allows participants to defer a portion of their annual compensation on a pre‑tax basis. Matching contributions to the 401(k) Plan may be made at the discretion of the Company’s board of directors. During the years ended December 31, 2019, 2018, and 2017 the Company made contributions totaling $0.2 million, $0.1 million and $42,000, respectively, to the 401(k) Plan. The Company provides a pension contribution plan for its employees in the United Kingdom, pursuant to which the Company may match employees’ contributions each year (“U.K Plan”). During the years ended December 31, 2019, 2018 and 2017 the Company made contributions totaling $0.3 million, $0.2 million and $0.2 million, respectively, to the U.K. Plan.

14. Benefit plans

The Company established a defined‑contribution savings plan under Section 401(k) of the Code (the “401(k) Plan”). The 401(k) Plan covers all U.S. employees and allows participants to defer a portion of their annual compensation on a pre‑tax basis. Matching contributions to the 401(k) Plan may be made at the discretion of the Company’s board of directors. During the years ended December 31, 2019, 2018, and 2017 the Company made contributions totaling $0.2 million, $0.1 million and $42,000, respectively, to the 401(k) Plan.

The Company provides a pension contribution plan for its employees in the United Kingdom, pursuant to which the Company may match employees’ contributions each year (“U.K Plan”). During the years ended December 31, 2019, 2018 and 2017 the Company made contributions totaling $0.3 million, $0.2 million and $0.2 million, respectively, to the U.K. Plan.