Subsequent Events (Details) $ in Millions	May 08, 2026 USD ($)
Subsequent Events
Estimated amount of tariff refunds	$ 57.0

Estimated amount of tariff refunds expected to be received that have not been recognized as a receivable as of the reporting date.

No definition available.

Name:	flnc_EstimatedTariffRefundReceivableNotRecognized
Namespace Prefix:	flnc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant