Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Taxes [Line Items]
Increase (decrease) in deferred tax assets valuation allowance	$ (29,600,000)	$ 45,300,000	$ (28,900,000)
Deferred tax assets, net operating loss carryforwards for federal	489,400,000
Deferred tax assets, net operating loss carryforwards for state	164,700,000
Federal research tax credit carryforwards	16,400,000
State research tax credit carryforwards	15,200,000
Accrued interest and/or penalties	0
French
Income Taxes [Line Items]
Deferred tax assets, net operating loss carryforwards for foreign	$ 147,900,000