Significant Accounting Policies - Cost of Products Sold (Details) - PEDMARK $ in Thousands	Mar. 31, 2025 USD ($)
Capitalized inventory costs reclassified to cost of products sold	$ 1,404
Manufacturing costs capitalized to inventory, work-in-process	665
Manufacturing costs capitalized to inventory, finished goods	1,256
Manufacturing costs capitalized to inventory, reserve allowance	$ 517

Manufacturing costs related to PEDMARK and capitalized to inventory, amount reclassified as cost.of products sold.

No definition available.

Name:	fenc_ManufacturingCostsCapitalizedToInventoryCostOfProductsSold
Namespace Prefix:	fenc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant