Revenue - Accounts Receivable (Details) $ in Thousands	6 Months Ended
Jun. 30, 2024 USD ($)
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance at December 31, 2023	$ 0
Increase in accounts receivable for drug product sales	713
Decrease in accounts receivable for cash collections	(713)
Balance as of June 30, 2024	$ 0

Amount, after allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business, classified as current.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481990/310-10-45-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 9
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481990/310-10-45-9

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Accounts Receivable, after Allowance for Credit Loss, Current, Decrease During Period

+ References

No definition available.

+ Details

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Namespace Prefix:	xfor_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Accounts Receivable, after Allowance for Credit Loss, Current, Increase During Period

+ References

No definition available.

+ Details

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Namespace Prefix:	xfor_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration