Receivable for Claimed Employee Retention Tax Credit (Details) - USD ($) $ in Thousands	3 Months Ended
Sep. 30, 2021	Jun. 30, 2021
Other Income and Expenses [Abstract]
ERTC refund	$ 431
ERTC expected receivable		$ 445

Payroll Tax Credit, Employee Retention Credit Under The CARES Act, Current

No definition available.

Name:	efoi_PayrollTaxCreditEmployeeRetentionCreditUnderTheCARESActCurrent
Namespace Prefix:	efoi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant