Stockholders' Equity - At the Market Offering (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Sep. 05, 2025
Stockholders' Equity
Aggregate offering price	$ 58,785	$ 150,000

Aggregate amount of common shares reserved for future issuance.

No definition available.

Name:	sldp_CommonStockCapitalReservedForFutureIssuance
Namespace Prefix:	sldp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant