Nature of the Business and Basis of Presentation - Additional Information (Detail) $ in Thousands		12 Months Ended
	Feb. 25, 2025	Dec. 31, 2024 USD ($) Patient	Dec. 31, 2023 USD ($)
Nature Of Business And Basis Of Presentation [Line Items]
Number of Patients | Patient		25
Entity incorporation month and year		2013-12
State of incorporation		DE
Net income (loss)		$ (68,566)	$ 22,806
Accumulated deficit		$ 459,638	$ 391,072
Description of letter from Listing Qualifications Department	On February 25, 2025, the Company received a deficiency letter from the Listing Qualifications Department informing it that it was not in compliance with the continued listing requirements of the Nasdaq Global Select Market because the bid price for its common stock had closed below $1.00 per share for 30 consecutive business days. The Company has until August 25, 2025 to regain compliance with the bid price requirement.
Spero Therapeutics LLC [Member]
Nature Of Business And Basis Of Presentation [Line Items]
Merger date		Jun. 30, 2017