Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Tax Contingency [Line Items]
Increase (decrease) in valuation allowance	$ 8,200,000
Unrecognized assets and liabilities related to uncertain tax positions	1,300,000
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	0	$ 0
Unrecognized tax benefit offset by change in valuation allowance	1,300,000
Internal Revenue Service (IRS) [Member]
Income Tax Contingency [Line Items]
Operating loss carryforwards	500,000
U.S. Federal Jurisdiction [Member]
Income Tax Contingency [Line Items]
Operating loss carryforwards	164,700,000
Operating loss carryforwards, carried forward indefinitely	57,400,000
U.S. Federal Jurisdiction [Member] | Research Tax Credit Carryforward [Member]
Income Tax Contingency [Line Items]
Tax credit carryforwards	1,700,000
State Tax Jurisdiction [Member]
Income Tax Contingency [Line Items]
Operating loss carryforwards	98,600,000
State Tax Jurisdiction [Member] | Research Tax Credit Carryforward [Member]
Income Tax Contingency [Line Items]
Tax credit carryforwards	1,100,000
Foreign Tax Authority [Member] | Her Majesty's Revenue and Customs (HMRC) [Member]
Income Tax Contingency [Line Items]
Operating loss carryforwards	$ 2,200,000