Benefit plans	12 Months Ended
	Dec. 31, 2020
Retirement Benefits [Abstract]
Benefits plans	Benefit plansThe Company maintains a 401(k) defined contribution retirement plan in the U.S. and a defined contribution plan in the U.K. for its employees and executive director. The assets of the plans are held separately from those of the Company in independently administered funds. The retirement plan cost charge represents the contributions payable by the Company to the plans during the year. Defined contribution costs during the years ended December 31, 2020 and 2019 amounted to $315 thousand and $203 thousand, respectively.