XOMA Corporation Quarterly report pursuant to Section 13 or 15(d)

Quarterly report pursuant to Section 13 or 15(d)

Capital Stock - Series B Preferred Stock (Details)

Capital Stock - Series B Preferred Stock (Details) $ / shares in Units, $ in Thousands		9 Months Ended		12 Months Ended
	Apr. 09, 2021 USD ($) D M $ / shares shares	Sep. 30, 2021 USD ($) $ / shares shares	Sep. 30, 2020 USD ($)	Dec. 31, 2020 $ / shares	Apr. 15, 2026 $ / shares	Apr. 15, 2025 $ / shares	Apr. 15, 2024 $ / shares	Apr. 15, 2023 $ / shares	Apr. 15, 2022 $ / shares	Aug. 05, 2021 shares
Sale of stock
Proceeds from issuance of preferred stock \| $		$ 40,000
Stock issuance costs \| $		$ 3,248	$ 231
Preferred stock, par value (in dollars per share)		$ 0.05		$ 0.05
8.375% Series B Cumulative, Perpetual Preferred Stock
Sale of stock
Depositary share's fractional interest in share of preferred stock \| shares	0.001	0.001
Preferred stock, dividend rate (as a percent)	8.375%	8.375%		8.375%
Preferred stock, par value (in dollars per share)	$ 0.05
Liquidation preference (in dollars per share)	25,000.00
Preferred stock, dividend amount (in dollars per share)	$ 2,093.75
Number of days in year over which dividend will be prorated and computed \| D	360
Number of months in year over which dividend will be prorated and compute \| M	12
Number of days in month over which dividend will be prorated and computed \| D	30
Redemption price at which company has option to redeem outstanding shares upon the occurrence of a delisting event or change of control event (in dollars per share)	$ 25,000.00
Share cap (in shares) \| shares	1,253.13
8.375% Series B Cumulative, Perpetual Preferred Stock \| Forecast [Member]
Sale of stock
Redemption price (in dollars per share)					$ 25,000.00	$ 25,250.00	$ 25,500.00	$ 25,750.00	$ 26,000.00
8.375% Series B Cumulative, Perpetual Preferred Stock \| 2021 ATM Agreement [Member]
Sale of stock
Depositary share's fractional interest in share of preferred stock \| shares										0.001
Depositary Shares
Sale of stock
Shares issued (in shares) \| shares	1,600,000
Purchase price (in dollars per share)	$ 25.00
Proceeds from issuance of preferred stock \| $	$ 40,000
Stock issuance costs \| $	2,900
Net proceeds from issuance of preferred stock \| $	$ 37,100
Share cap (in shares) \| shares	1.25313
Depositary Shares \| Forecast [Member]
Sale of stock
Redemption price (in dollars per share)					$ 25.00	$ 25.25	$ 25.50	$ 25.75	$ 26.00
Depositary Shares \| Spouse of James Neal, Chief Executive Officer and a director
Sale of stock
Shares issued (in shares) \| shares	8,000
Purchase price (in dollars per share)	$ 25.00
Proceeds from issuance of preferred stock \| $	$ 200
Depositary Shares \| 2021 ATM Agreement [Member]
Sale of stock
Shares issued (in shares) \| shares		0