Subsequent Events (Details) - USD ($)			12 Months Ended
Subsequent Events (Details) - USD ($)	Jan. 15, 2026	Jun. 22, 2021	Dec. 31, 2025	Dec. 31, 2024	Mar. 06, 2026	Apr. 25, 2025
Subsequent Event [Line Items]
Issuance of stock from warrant exercises (in shares)			403,372	0
Perceptive Term Loan Facility \| Credit Agreement Warrants
Subsequent Event [Line Items]
Class of warrant or right, vested and exercisable (in shares)						750,000
Amended Loan Agreement \| Credit Agreement Warrants
Subsequent Event [Line Items]
Class of warrant or right, vested and exercisable (in shares)						600,000
Delayed Draw Term Loan \| Perceptive Term Loan Facility \| Perceptive Credit Holdings IV, LP \| Line of Credit
Subsequent Event [Line Items]
Line of credit facility, maximum borrowing capacity						$ 75,000,000.0
Exchanging Stockholders
Subsequent Event [Line Items]
Exchange agreement, number of shares exchanged (in shares)		804,951
Number of common shares to be called upon exercise of warrants (in shares)		804,951
Subsequent Event
Subsequent Event [Line Items]
Issuance of stock from warrant exercises (in shares)	804,788
Subsequent Event \| Perceptive Term Loan Facility \| Credit Agreement Warrants
Subsequent Event [Line Items]
Class of warrant or right, vested and exercisable (in shares)					750,000
Subsequent Event \| Amended Loan Agreement \| Credit Agreement Warrants
Subsequent Event [Line Items]
Class of warrant or right, vested and exercisable (in shares)					600,000
Subsequent Event \| Delayed Draw Term Loan \| Tranche B Loan \| Perceptive Credit Holdings IV, LP \| Line of Credit
Subsequent Event [Line Items]
Line of credit facility, maximum borrowing capacity					$ 10,000,000.0

EXAGEN INC. 10-K