Income Taxes - Additional Information (Detail) - USD ($)	1 Months Ended	12 Months Ended
	Aug. 31, 2004	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Taxes [Line Items]
Valuation allowance of deferred tax assets		$ 698,228,000	$ 705,034,000
Change in the valuation allowance		6,800,000	9,940,000	$ 19,631,000
Federal operating loss carryforwards		2,000,000,000
State operating loss carryforwards		1,300,000,000
Federal operation loss carryforwards, not subject to expiration		$ 494,000,000
Operating loss carryforwards, limitations on use		Pursuant to IRC Sections 382 and 383, annual use of the Company’s federal and California net operating loss and research and development credit carryforwards may be limited in the event a cumulative change in ownership of more than 50% occurs within a three-year period.
Net operating loss carryforwards	$ 105,800,000
Net operating loss and credit carryforwards, annual use limitation	$ 13,000,000
Research and development credit expired		2023
Research and development credits expire		$ 1,100,000
Unrecognized income tax interest and penalties		0	$ 0	$ 0
Federal
Income Taxes [Line Items]
Research and development credits not expire		$ 54,200,000
Research and development credits begin to expire		2024
State
Income Taxes [Line Items]
Research and development credits not expire		$ 22,800,000
Connecticut
Income Taxes [Line Items]
Research and development credits not expire		$ 19,800,000