Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021
Statement of Cash Flows [Abstract]
Accrued expenses and other current and long-term liabilities, related party amounts	$ 3,087	$ 31,683

Accrued expenses and other current and long-term liabilities related party amounts.

No definition available.

Name:	mcrb_AccruedExpensesAndOtherCurrentAndLongTermLiabilitiesRelatedPartyAmounts
Namespace Prefix:	mcrb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration