Summary of Significant Accounting Policies - Additional Information (Detail)	Jun. 30, 2020 USD ($)
Essentialis, Inc. [Member] \| Earnout Payments [Member]
Schedule Of Significant Accounting Policies [Line Items]
Maximum potential cash earnout payments	$ 30,000,000

Asset acquisition contingent consideration arrangements.

No definition available.

Name:	slno_AssetAcquisitionContingentConsiderationArrangements
Namespace Prefix:	slno_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant