Consolidated Statements of Cash Flows (Parenthetical) $ in Thousands	12 Months Ended
Dec. 31, 2019 USD ($)
Consolidated Statements of Cash Flows
Common stock warrant liability issuance costs	$ 1,442

The amount of common stock warrant liability issuance cost.

No definition available.

Name:	rsls_WarrantLiabilityIssuanceCost
Namespace Prefix:	rsls_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration