Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Taxes [Line Items]
Deferred Tax Valuation allowance increase (decrease)	$ 21.0	$ 25.2
Federal [Member]
Income Taxes [Line Items]
Net operating loss carryforwards	$ 527.1
Operating loss carryforwards, expiration date	Dec. 31, 2024
Federal [Member] | Research Tax Credit Carryforward
Income Taxes [Line Items]
Tax credit carryforwards	$ 6.3
Tax credit carryforwards, expiration date	Dec. 31, 2027
State and Local Jurisdiction [Member]
Income Taxes [Line Items]
Net operating loss carryforwards	$ 303.4
Operating loss carryforwards, expiration date	Dec. 31, 2020
State and Local Jurisdiction [Member] | Research Tax Credit Carryforward
Income Taxes [Line Items]
Tax credit carryforwards	$ 3.9
Tax credit carryforwards, expiration date	Dec. 31, 2027