Note 1 - General (Details Textual) - USD ($) $ in Thousands	Sep. 30, 2025	Dec. 31, 2024	Sep. 30, 2024
Employee Retention Credit Receivable	$ 0	$ 1,677	$ 1,677

Represents the receivable for the Employee Retention Credit ("ERC").

No definition available.

Name:	ftek_EmployeeRetentionCreditReceivable
Namespace Prefix:	ftek_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant