XOMA Corporation Annual report pursuant to Section 13 and 15(d)

Annual report pursuant to Section 13 and 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	10 Months Ended	12 Months Ended					13 Months Ended
	Jan. 30, 2019 USD ($)	Jan. 07, 2019 USD ($)	Apr. 03, 2018 USD ($) shares	Mar. 31, 2019 USD ($)	Apr. 30, 2018 USD ($) shares	Mar. 31, 2018 USD ($) item shares	Dec. 31, 2020 USD ($)	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)	Sep. 30, 2019 USD ($)	Dec. 31, 2018 shares	Dec. 31, 2020 USD ($) shares	Mar. 31, 2020 USD ($)	Dec. 31, 2019 shares	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Mar. 31, 2019 USD ($)
Licensing and other arrangements
Revenues							$ 27,580	$ 557	$ 444	$ 804	$ 422	$ 8,855	$ 962	$ 8,131				$ 29,385			$ 18,370
Revenue from contracts with customers																		$ 27,941			17,276
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		$ 8,500
Number of Rezolute's common stock eligible to receive contingent on completion of financing activities \| shares						7,000,000
Number of post-split shares eligible to receive \| shares						140,000
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
Number of Rezolute's shares Company has right and option to sell if Rezolute does not list common stock shares on national exchange \| shares																		100,000
Revenues															$ 0
Transaction price			$ 1,800
Transaction price, Shares received (in shares) \| shares			8,093,010
Post-split shares received (in shares) \| shares			161,860
Transaction price, Value of common stock received			$ 1,000
Transaction price, cash consideration			500
Reimbursable technology transfer expense received	$ 300		$ 300
Number of arrangements \| item						1
Number of performance obligations \| item						1
Revenue from contracts with customers				$ 2,500								$ 6,000				$ 14,000		$ 0			$ 14,000	$ 1,800
Rezolute \| License Agreement
Licensing and other arrangements
Reimbursable technology transfer expense received					$ 300
Rezolute \| Common Stock Purchase Agreement
Licensing and other arrangements
Number of post-split shares eligible to receive \| shares																	100,000
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	2,500,000		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%
Transaction price, Shares received (in shares) \| shares					8,093,010
Post-split shares received (in shares) \| shares					161,860
Transaction price, cash consideration					$ 500