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

Quarterly report pursuant to Section 13 or 15(d)

Subsequent Events - Additional Information (Details)

Subsequent Events - Additional Information (Details)					1 Months Ended	3 Months Ended
Subsequent Events - Additional Information (Details)	May 07, 2018 USD ($) $ / shares shares	Apr. 14, 2018 USD ($) Facility	Apr. 02, 2018 USD ($) shares	Nov. 21, 2017 USD ($) Facility	Apr. 30, 2018 USD ($) shares	Mar. 31, 2018 USD ($)	Mar. 31, 2017 USD ($)
Subsequent Event [Line Items]
Proceeds from issuance of common stock						$ 2,309,000	$ 5,380,000
Operating leases, number of portions of leased facilities \| Facility				1
Operating leases, number of leased facilities \| Facility				3
Operating leases, sublease commencement date				Dec. 26, 2017
Operating leases sublease income receivable				$ 5,100,000
Operating leases sublease expiry date				2023-04
Sublease tenant improvement allowance				$ 800,000
Subsequent Events [Member]
Subsequent Event [Line Items]
Operating leases, number of portions of leased facilities \| Facility		1
Operating leases, number of leased facilities \| Facility		3
Operating leases, sublease commencement date		May 01, 2018
Operating leases sublease income receivable		$ 1,100,000
Operating leases sublease expiry date		2023-04
Sublease tenant improvement allowance		$ 65,000
Loan and Security Agreement [Member] \| Subsequent Events [Member] \| Silicon Valley Bank [Member] \| Warrants for Common Stock [Member]
Subsequent Event [Line Items]
Aggregate number of shares of common stock called by warrants \| shares	6,332
Exercise price of per share \| $ / shares	$ 23.69
Exercisable period of warrants	10 years
Loan and Security Agreement [Member] \| Subsequent Events [Member] \| Term Loan [Member] \| Silicon Valley Bank [Member]
Subsequent Event [Line Items]
Maximum borrowing capacity under loan agreement	$ 20,000,000
Gross cash proceeds received from milestone and licensing payments	$ 20,000,000
Earlier effecitve date of term loan	Mar. 31, 2019
Effective date of term loan extended	Mar. 31, 2020
Basis spread on variable rate	4.75%
Variable rate basis	The interest-only period will be followed by equal monthly payments of principal and interest over 24 months. Each Term Loan Advance will mature at the earlier of (i) the 23 months following the applicable term loan amortization date for each such Term Loan Advance (ii) March 1, 2023, or (iii) 30 days prior to the earliest maturity of any portion of the Company’s loan with Novartis (the “Loan Maturity Date”). After repayment, no Term Loan Advance (or any portion thereof) may be reborrowed.
Period of monthly payments of principal and interest	24 months
Repayment of term loan	$ 0
Loan borrowed	$ 0
Percentage of final payment of Loan	8.50%
Percentage of prepayment fee	3.00%
Additional interest rate of outstanding payments due	4.00%
Percentage of unused portion of term loan	1.00%
Loan and Security Agreement [Member] \| Subsequent Events [Member] \| Term Loan [Member] \| Silicon Valley Bank [Member] \| First Anniversary [Member]
Subsequent Event [Line Items]
Percentage of amount prepaid	2.00%
Loan and Security Agreement [Member] \| Subsequent Events [Member] \| Term Loan [Member] \| Silicon Valley Bank [Member] \| Second Anniversary [Member]
Subsequent Event [Line Items]
Percentage of amount prepaid	1.00%
Loan and Security Agreement [Member] \| Subsequent Events [Member] \| Term Loan [Member] \| Prime Rate [Member] \| Silicon Valley Bank [Member]
Subsequent Event [Line Items]
Basis spread on variable rate	0.25%
Loan and Security Agreement [Member] \| Subsequent Events [Member] \| Novartis [Member] \| Silicon Valley Bank [Member]
Subsequent Event [Line Items]
Days of interest, period	30 days
Earliest maturity of loan	30 days
Maturity date	Mar. 01, 2023
Rezolute [Member] \| Amended Common Stock Purchase Agreement [Member] \| Subsequent Events [Member]
Subsequent Event [Line Items]
Gross proceeds from convertible note finaning			$ 4,000,000
Issuance of common stock, shares \| shares			8,023,758		69,252
Proceeds from issuance of common stock			$ 500,000		$ 50,000