Selected Quarterly Financial Information (Unaudited) - Schedule of Unaudited Quarterly Result of Operations (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0
Operating expenses	22,386	19,150	18,178	15,973	15,161	13,696	11,887	14,113	75,687	54,857	25,576
Loss from operations	(22,386)	(19,150)	(18,178)	(15,973)	(15,161)	(13,696)	(11,887)	(14,113)	(75,687)	(54,857)	(25,576)
Net loss	(21,921)	(19,020)	(17,980)	(15,877)	(14,487)	(13,505)	(11,311)	(13,875)	(74,798)	(53,178)	(23,773)
Net loss attributable to Solid Biosciences Inc./Solid Biosciences, LLC	(21,921)	(19,020)	(17,980)	(15,877)	(14,487)	(13,505)	(11,311)	(12,815)	(74,798)	(52,118)	(21,539)
Net loss attributable to common stockholders/unitholders	$ (21,921)	$ (19,020)	$ (17,980)	$ (15,877)	$ (14,487)	$ (13,505)	$ (11,311)	$ (14)	$ (74,798)	$ (39,317)	$ (17,230)
Net loss per share/unit attributable to common stockholders/unitholders	$ (0.63)	$ (0.55)	$ (0.52)	$ (0.54)	$ (0.84)	$ (0.79)	$ (0.66)	$ (0.01)	$ (2.25)	$ (2.88)	$ (10.14)