Income Taxes - Additional Information (Detail) £ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2022 GBP (£)
Statutory federal corporate income tax rate	21.00%	21.00%
Changes in valuation allowance	$ 26,083,000	$ 15,748,000
Unrecognized tax benefits	0	0
Unrecognized tax benefits recognized in comprehensive income (loss)	0
Accrued penalties or interest related to uncertain tax positions	0	$ 0
Research and development expenditures capitalized	49,600,000
U.S. Federal [Member]
Operating loss carry forwards	321,600,000
Net operating loss carry forwards	$ 151,800,000
Operating loss carry forwards, expiration range start dates	2023
Operating loss carry forwards, expiration range end dates	2038
Tax years that remain subject to examination	2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021
State [Member]
Operating loss carry forwards	$ 264,200,000
Operating loss carry forwards, expiration range start dates	2033
Operating loss carry forwards, expiration range end dates	2039
United Kingdom Tax Authority [Member]
Operating loss carry forwards	$ 25,300,000		£ 20.9
Tax years that remain subject to examination	2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021
Federal and State Research and Development Tax Credit Carryforward [Member]
Research and development tax credit carry forwards	$ 7,200,000
Federal And State Tax [Member]
Research and development tax credit carry forwards expiration begin date	2022
Research and development tax credit carry forwards expiration end date	2039
Icon Bioscience Inc [Member] | U.S. Federal [Member]
Operating loss carry forwards	$ 49,300,000