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

Quarterly report pursuant to Section 13 or 15(d)

Licensing and Other Arrangements - Rezolute - First Amendment (Details)

Licensing and Other Arrangements - Rezolute - First Amendment (Details) $ in Thousands				1 Months Ended			3 Months Ended			9 Months Ended		12 Months Ended			13 Months Ended
	Jan. 30, 2019 USD ($)	Jan. 07, 2019 USD ($)	Apr. 03, 2018 USD ($) item shares	Mar. 31, 2019 USD ($)	Apr. 30, 2018 USD ($) shares	Mar. 31, 2018 USD ($) shares	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Mar. 31, 2018 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2019 shares	Dec. 31, 2018 USD ($)	Mar. 31, 2019 USD ($)
Licensing and other arrangements
Revenues							$ 557	$ 8,855		$ 1,804	$ 17,948
Revenue from contracts with customers							200	8,525		753	$ 17,176
Rezolute
Licensing and other arrangements
Revenues									$ 0
Rezolute \| License Agreement and Common Stock Purchase Agreement
Licensing and other arrangements
Amount of cash eligible to receive						$ 6,000
Amount of Rezolute's common stock eligible to receive		$ 8,500				$ 8,500
Number of Rezolute's common stock eligible to receive contingent on completion of financing activities \| shares						7,000,000
Gross proceeds to be raised for qualified financing															$ 20,000
Additional common stock to be received if Rezolute did not complete financing															$ 8,500
Common stock trading period															10 days
Eligible to receive, in order to maintain license agreement												$ 15,000
Transaction price, Shares received (in shares) \| shares			8,093,010		8,093,010
Transaction price, cash consideration			$ 500		$ 500
Number of arrangements \| item			1
Transaction price			$ 1,800
Transaction price, Value of common stock received			1,000
Reimbursable technology transfer expense received	$ 300		300
Upfront consideration to incremental discount for future payment			0
Revenue from contracts with customers				$ 2,500				$ 6,000						$ 1,800
Rezolute \| License Agreement
Licensing and other arrangements
Reimbursable technology transfer expense received			$ 300
Revenue from contracts with customers							$ 0			$ 0
Rezolute \| Common Stock Purchase Agreement
Licensing and other arrangements
Number of Rezolute's shares Company has right and option to sell if Rezolute does not list common stock shares on national exchange \| shares						5,000,000							5,000,000
Percent of Rezolute's shares held Company has right and option to sell if Rezolute does not list common stock shares on national exchange						33.33%