United Kingdom (U.K.) Research and Development (R&D) Tax Relief Scheme (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended	6 Months Ended
	Dec. 31, 2019	Mar. 31, 2020	Jun. 30, 2021
U.K. tax legislation | U.K. tax legislation
Operating Loss Carryforwards [Line Items]
Window to seek relief under U.K. tax legislature			2 years
Tax year 2017
Operating Loss Carryforwards [Line Items]
Claim for refundable cash credit	$ 9.9
Proceeds from claims	9.9
Tax year 2018
Operating Loss Carryforwards [Line Items]
Claim for refundable cash credit	9.8
Proceeds from claims	$ 9.8
2017 and 2018 tax year claims
Operating Loss Carryforwards [Line Items]
Other income		$ 19.7