COMMITMENTS (Schedule of Future Minimum Lease Commitments) (Details) $ in Thousands	Jun. 30, 2019 USD ($)
Commitments and Contingencies Disclosure [Abstract]
2019	$ 746
2020	682
2021 and thereafter	21
Total	$ 1,449

Amount of lessee's undiscounted obligation for lease payments for operating lease, due in third fiscal year following latest fiscal year and thereafter, under the alternative modified transition method.

No definition available.

Name:	fomx_LesseeOperatingLeaseLiabilityPaymentsDueYearThreeAndThereafterAlternativeModifiedTransitionMethod
Namespace Prefix:	fomx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant