XOMA (XOMA) 10-Q 5 Aug 21 2021 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2021	Aug. 02, 2021
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2021
Document Transition Report	false
Entity File Number	001-39801
Entity Registrant Name	XOMA Corporation
Entity Incorporation State Country Code	DE
Entity Tax Identification Number	52-2154066
Entity Address Address Line1	2200 Powell Street
Entity Address Address Line2	Suite 310
Entity Address City Or Town	Emeryville
Entity Address State Or Province	CA
Entity Address Postal Zip Code	94608
City Area Code	510
Local Phone Number	204-7200
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		11,311,231
Entity Central Index Key	0000791908
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
Amendment Flag	false
Common Stock
Security12b Title	Common Stock, $0.0075 par value
Trading Symbol	XOMA
Security Exchange Name	NASDAQ
8.625% Series A Cumulative, Perpetual Preferred Stock
Security12b Title	8.625% Series A Cumulative Perpetual Preferred Stock, par value $0.05
Trading Symbol	XOMAP
Security Exchange Name	NASDAQ
Depositary Shares
Security12b Title	Depositary Shares (each representing 1/1000th interest in a share of 8.375% Series B Cumulative Perpetual Preferred Stock, par value $0.05)
Trading Symbol	XOMAO
Security Exchange Name	NASDAQ

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Cash	$ 78,945	$ 84,222
Restricted cash	4,840	1,611
Short-term equity securities	2,310
Trade and other receivables, net	12	263
Income tax receivable		1,526
Prepaid expenses and other current assets	1,144	443
Total current assets	87,251	88,065
Long-term restricted cash		531
Property and equipment, net	17	21
Operating lease right-of-use assets	281	359
Long-term royalty receivables	48,075	34,575
Long-term equity securities		1,693
Other assets	128	41
Total assets	135,752	125,285
Current liabilities:
Accounts payable	629	456
Accrued and other liabilities	1,059	642
Contingent consideration under royalty purchase agreements	75	75
Operating lease liabilities	187	179
Unearned revenue recognized under units-of-revenue method	1,503	1,452
Contingent liabilities	1,410	1,410
Current portion of long-term debt		8,088
Preferred stock dividend accrual	1,424
Total current liabilities	6,287	12,302
Unearned revenue recognized under units-of-revenue method - long-term	12,734	13,516
Long-term debt		12,764
Long-term operating lease liabilities	133	229
Other liabilities - long-term	20	50
Total liabilities	19,174	38,861
Commitments and Contingencies (Note 10)
Stockholders' equity:
Common stock, $0.0075 par value, 277,333,332 shares authorized, 11,310,001 and 11,228,792 shares issued and outstanding at June 30, 2021 and December 31, 2020, respectively	85	84
Additional paid-in capital	1,307,140	1,267,377
Accumulated deficit	(1,190,696)	(1,181,086)
Total stockholders' equity	116,578	86,424
Total liabilities and stockholders' equity	135,752	125,285
8.625% Series A Cumulative, Perpetual Preferred Stock
Stockholders' equity:
Preferred Stock	49	49
8.375% Series B Cumulative, Perpetual Preferred Stock
Stockholders' equity:
Preferred Stock
Convertible preferred stock.
Stockholders' equity:
Preferred Stock

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	6 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Preferred stock, par value (in dollars per share)	$ 0.05	$ 0.05
Preferred stock, shares authorized (in shares)	1,000,000	1,000,000
Common stock, par value (in dollars per share)	$ 0.0075	$ 0.0075
Common stock, shares authorized (in shares)	277,333,332	277,333,332
Common stock, shares issued (in shares)	11,310,001	11,228,792
Common stock, shares outstanding (in shares)	11,310,001	11,228,792
8.625% Series A Cumulative, Perpetual Preferred Stock
Preferred stock, dividend rate (as a percent)	8.625%	8.625%
Preferred stock, shares issued (in shares)	984,000	984,000
Preferred stock, shares outstanding (in shares)	984,000	984,000
8.375% Series B Cumulative, Perpetual Preferred Stock
Preferred stock, dividend rate (as a percent)	8.375%	8.375%
Preferred stock, shares issued (in shares)	1,600	0
Preferred stock, shares outstanding (in shares)	1,600	0
Convertible preferred stock.
Preferred stock, shares issued (in shares)	5,003	5,003
Preferred stock, shares outstanding (in shares)	5,003	5,003

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenues:
Revenue from contracts with customers	$ 525	$ 53	$ 544	$ 553
Revenue recognized under units-of-revenue method	376	391	731	695
Total revenues	901	444	1,275	1,248
Operating expenses:
Research and development	38	38	99	100
General and administrative	3,927	3,557	10,667	9,914
Total operating expenses	3,965	3,595	10,766	10,014
Loss from operations	(3,064)	(3,151)	(9,491)	(8,766)
Other income (expense), net:
Interest expense	(172)	(508)	(461)	(1,050)
Loss on extinguishment of debt	(300)		(300)
Other income (expense), net	1,299	126	642	(1)
Loss before income tax	(2,237)	(3,533)	(9,610)	(9,817)
Income tax benefit			0	1,526
Net loss	(2,237)	(3,533)	(9,610)	(8,291)
Net comprehensive loss	(2,237)	(3,533)	(9,610)	(8,291)
Less: accumulated dividends on Series A and Series B preferred stock	(1,293)		(1,824)
Net loss available to common stockholders, basic	(3,530)	(3,533)	(11,434)	(8,291)
Net loss available to common stockholders, diluted	$ (3,530)	$ (3,533)	$ (11,434)	$ (8,291)
Basic net loss per share of common stock (in dollars per share)	$ (0.31)	$ (0.33)	$ (1.02)	$ (0.81)
Diluted net loss per share of common stock (in dollars per share)	$ (0.31)	$ (0.33)	$ (1.02)	$ (0.81)
Weighted average shares used in computing basic net loss per share available to common stockholders	11,285	10,824	11,263	10,292
Weighted average shares used in computing diluted net loss per share available to common stockholders	11,285	10,824	11,263	10,292

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Preferred stock8.625% Series A Cumulative, Perpetual Preferred Stock	Preferred stock8.375% Series B Cumulative, Perpetual Preferred Stock	Preferred stockConvertible preferred stock.	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Total
Balance at Dec. 31, 2019				$ 73	$ 1,238,299	$ (1,194,384)	$ 43,988
Balance (in shares) at Dec. 31, 2019			6,000	9,759,000
Increase (Decrease) in Stockholders' Equity
Issuance of common stock related to 401(k) contribution					88		88
Issuance of common stock related to 401(k) contribution (in shares)				3,000
Stock-based compensation expense					1,788		1,788
Disgorgement of stockholder's short-swing profits					13		13
Net loss						(4,758)	(4,758)
Balance at Mar. 31, 2020				$ 73	1,240,188	(1,199,142)	41,119
Balance (in shares) at Mar. 31, 2020			6,000	9,762,000
Balance at Dec. 31, 2019				$ 73	1,238,299	(1,194,384)	43,988
Balance (in shares) at Dec. 31, 2019			6,000	9,759,000
Increase (Decrease) in Stockholders' Equity
Net loss							(8,291)
Balance at Jun. 30, 2020				$ 83	1,240,987	(1,202,675)	38,395
Balance (in shares) at Jun. 30, 2020			5,000	11,018,000
Balance at Mar. 31, 2020				$ 73	1,240,188	(1,199,142)	41,119
Balance (in shares) at Mar. 31, 2020			6,000	9,762,000
Increase (Decrease) in Stockholders' Equity
Exercise of stock options					10		10
Exercise of stock options (in shares)				2,000
Issuance of common stock related to ESPP					26		26
Issuance of common stock related to ESPP (in shares)				1,000
Stock-based compensation expense					773		773
Issuance of common stock related to Series Y preferred stock conversion				$ 10	(10)
Issuance of common stock related to Series Y preferred stock conversion (in shares)			(1,000)	1,253,000
Net loss						(3,533)	(3,533)
Balance at Jun. 30, 2020				$ 83	1,240,987	(1,202,675)	38,395
Balance (in shares) at Jun. 30, 2020			5,000	11,018,000
Balance at Dec. 31, 2020	$ 49			$ 84	1,267,377	(1,181,086)	86,424
Balance (in shares) at Dec. 31, 2020	984,000		5,000	11,229,000
Increase (Decrease) in Stockholders' Equity
Exercise of stock options					388		388
Exercise of stock options (in shares)				24,000
Exercise of common stock warrants (in shares)				5,000
Issuance of common stock related to 401(k) contribution					90		90
Issuance of common stock related to 401(k) contribution (in shares)				2,000
Stock-based compensation expense					2,898		2,898
Preferred stock dividends					(707)		(707)
Net loss						(7,373)	(7,373)
Balance at Mar. 31, 2021	$ 49			$ 84	1,270,046	(1,188,459)	81,720
Balance (in shares) at Mar. 31, 2021	984,000		5,000	11,260,000
Balance at Dec. 31, 2020	$ 49			$ 84	1,267,377	(1,181,086)	$ 86,424
Balance (in shares) at Dec. 31, 2020	984,000		5,000	11,229,000
Increase (Decrease) in Stockholders' Equity
Exercise of stock options (in shares)							73,575
Net loss							$ (9,610)
Balance at Jun. 30, 2021	$ 49			$ 85	1,307,140	(1,190,696)	116,578
Balance (in shares) at Jun. 30, 2021	984,000	2,000	5,000	11,310,000
Balance at Mar. 31, 2021	$ 49			$ 84	1,270,046	(1,188,459)	81,720
Balance (in shares) at Mar. 31, 2021	984,000		5,000	11,260,000
Increase (Decrease) in Stockholders' Equity
Exercise of stock options				$ 1	593		594
Exercise of stock options (in shares)				49,000
Issuance of common stock related to ESPP					17		17
Issuance of common stock related to ESPP (in shares)				1,000
Stock-based compensation expense					768		768
Issuance of stock					37,140		37,140
Issuance of stock, net (in shares)		2,000
Preferred stock dividends					(1,424)		(1,424)
Net loss						(2,237)	(2,237)
Balance at Jun. 30, 2021	$ 49			$ 85	$ 1,307,140	$ (1,190,696)	$ 116,578
Balance (in shares) at Jun. 30, 2021	984,000	2,000	5,000	11,310,000

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS $ in Thousands	6 Months Ended
	Jun. 30, 2021USD ($)	Jun. 30, 2020USD ($)
Cash flows from operating activities:
Net loss	$ (9,610)	$ (8,291)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	3,666	2,561
Common stock contribution to 401(k)	90	88
Depreciation and amortization	4	12
Amortization of debt issuance costs, debt discount and final payment on debt	200	374
Provision for bad debt		1,409
Non-cash lease expense	79	74
Loss on extinguishment of debt	300
Change in fair value of equity securities	(617)	150
Changes in assets and liabilities:
Trade and other receivables, net	251	1,113
Income tax receivable	1,526	(1,526)
Prepaid expenses and other assets	(701)	(497)
Accounts payable and accrued liabilities	748	(152)
Operating lease liabilities	(88)	(79)
Unearned revenue recognized under units-of-revenue method	(731)	(695)
Other liabilities	(6)	309
Net cash used in operating activities	(4,889)	(5,150)
Cash flows from investing activities:
Payments related to purchase of royalty rights	(13,500)
Net cash used in investing activities	(13,500)
Cash flows from financing activities:
Proceeds from issuance of preferred stock	40,000
Proceeds from issuance of common stock		26
Payment of preferred and common stock issuance costs	(3,106)	(211)
Proceeds from exercise of options	1,355	25
Principal payments - debt	(4,250)	(1,875)
Payment for extinguishment of debt	(17,103)
Payment for debt modification fee	(24)
Payment for preferred stock dividends	(707)
Principal payments - finance lease		(9)
Proceeds from disgorgement of stockholder's short-swing profits		13
Taxes paid related to net share settlement of equity awards	(355)	(16)
Net cash provided by (used in) financing activities	15,810	(2,047)
Net decrease in cash and restricted cash	(2,579)	(7,197)
Cash and restricted cash at the beginning of the period	86,364	56,688
Cash and restricted cash at the end of the period	83,785	49,491
Supplemental Cash Flow Information:
Cash paid for interest	311	379
Non-cash investing and financing activities:
Preferred stock dividend accrual	1,424
Interest added to principal balance on long-term debt		317
Accrued cost related to issuance of common stock		$ 19
Accrued cost related to issuance of preferred stock	$ 105

Description of Business

Description of Business	6 Months Ended
	Jun. 30, 2021
Description of Business
Description of Business	1. Description of Business XOMA Corporation (referred to as “XOMA” or the “Company”), a Delaware corporation, is a biotech royalty aggregator with a sizable portfolio of economic rights to future potential milestone and royalty payments associated with partnered pre-commercial therapeutic candidates. The Company’s portfolio was built through licensing its proprietary products and platforms from its legacy discovery and development business, combined with acquisitions of rights to future milestones and royalties that the Company has made since the royalty aggregator business model was implemented in 2017. The Company’s drug royalty aggregator business is focused on early to mid-stage clinical assets primarily in Phase 1 and 2 with blockbuster potential licensed to large-cap partners. The Company expects that most of its future revenue will be based on payments the Company may receive for milestones and royalties related to these programs. Liquidity and Financial Condition The Company has incurred significant operating losses and negative cash flows from operations since its inception. As of June 30, 2021, the Company had unrestricted and restricted cash of $83.8 million. The restricted cash balance may only be used to pay dividends on the 8.625% Series A cumulative, perpetual preferred stock (“Series A Preferred Stock”) issued in December 2020 and the depositary shares, each representing 1/1000th ​ In June 2021, the Company repaid its outstanding debt obligations to Silicon Valley Bank (“SVB”) and Novartis Pharma AG (“Novartis”), for a total of $17.1 million (Note 8). Based on the Company’s current cash balance and its ability to control discretionary spending, such as royalty acquisitions, the Company has evaluated and concluded its financial condition is sufficient to fund its planned operations and commitments and contractual obligations for a period of at least one year following the date that these condensed consolidated financial statements are issued. ​

Basis of Presentation and Signi

Basis of Presentation and Significant Accounting Policies	6 Months Ended
	Jun. 30, 2021
Basis of Presentation and Significant Accounting Policies
Basis of Presentation and Significant Accounting Policies	2. Basis of Presentation and Significant Accounting Policies Basis of Presentation The condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany accounts and transactions among consolidated entities were eliminated upon consolidation. The unaudited condensed consolidated financial statements were prepared in accordance with generally accepted accounting principles (“GAAP”) in the United States for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. As permitted under those rules certain footnotes or other financial information can be condensed or omitted. These financial statements and related disclosures have been prepared with the assumption that users of the interim financial information have read or have access to the audited consolidated financial statements for the preceding fiscal year. Accordingly, these statements should be read in conjunction with the audited consolidated financial statements and related notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020, filed with the U.S. Securities and Exchange Commission (“SEC”) on March 10, 2021. These financial statements have been prepared on the same basis as the Company’s annual consolidated financial statements and, in the opinion of management, reflect all adjustments, consisting only of normal recurring adjustments that are necessary for a fair statement of the Company’s consolidated financial information. The interim results of operations are not necessarily indicative of the results that may be expected for the full year. Use of Estimates The preparation of financial statements in conformity with GAAP in the United States requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenue and expenses, and related disclosures. On an ongoing basis, management evaluates its estimates including, but not limited to, those related to revenue recognition, revenue recognized under units-of-revenue method, equity securities, legal contingencies and stock-based compensation. The Company bases its estimates on historical experience and on various other market-specific and other relevant assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ significantly from these estimates, such as the Company’s billing under government contracts and amortization of the payments received from HealthCare Royalty Partners II, L.P. (“HCRP”). Under the Company’s contracts with the National Institute of Allergy and Infectious Diseases (“NIAID”), a part of the National Institutes of Health (“NIH”), the Company billed using NIH’s provisional rates and thus is subject to future audits at the discretion of NIAID’s contracting office. In October of 2019, NIH notified the Company that it engaged KPMG to perform an audit of the Company’s incurred cost submissions for 2013, 2014 and 2015. The audit procedures were completed and the Company adjusted its estimated liability owed to NIH to $1.4 million as of December 31, 2020 (Note 4). The estimated liability owed to NIH had not changed as of June 30, 2021. The audit remains subject to further review by NIH as part of the contract close-out process, which includes finalization of rates for years 2010 through 2015, and the Company may incur further liability as a result. In addition, under the contracts with HCRP, the amortization for the reporting period is calculated based on the payments expected to be made by the licensees to HCRP over the term of the arrangement. Any changes to the estimated payments by the licensees to HCRP can result in a material adjustment to revenue previously reported. The COVID-19 pandemic has resulted in a global slowdown of economic activity which has led to delays and could result in further delays or terminations of some clinical trials underlying the Company’s royalty purchase agreements. Estimates and assumptions about future events and their effects cannot be determined with certainty and therefore require the exercise of judgment. These estimates may change, as new events occur and additional information is obtained, and are recognized in the condensed consolidated financial statements as soon as they become known. Actual results could differ from those estimates and any such differences may be material to the Company’s financial statements. Cash and Restricted Cash Cash consists of bank deposits held in business checking and interest-bearing deposit accounts. As of June 30, 2021, the Company did not have any cash equivalent balances, defined as highly liquid financial instruments purchased with original maturities of three months or less. Restricted cash consists of bank deposits held to pay dividends on the Company’s Series A Preferred Stock and Series B Preferred Stock. The Company maintains cash and restricted cash balances at commercial banks. Balances commonly exceed the amount insured by the Federal Deposit Insurance Corporation. The Company has not experienced any losses in such accounts, and management believes that the Company is not exposed to any significant credit risk with respect to such cash and restricted cash. ​ The following table provides a reconciliation of cash and restricted cash reported within the consolidated balance sheets that sum to the total of the same amounts shown in the consolidated statements of cash flows (in thousands): ​ ​ ​ ​ ​ ​ ​ Six Months Ended June 30, ​ 2021 ​ 2020 ​ ​ ​ ​ ​ ​ Cash $ 78,945 ​ $ 49,491 Restricted cash ​ 4,840 ​ ​ — Total cash and restricted cash $ 83,785 ​ $ 49,491 ​ Revenue Recognition The Company recognizes revenue from all contracts with customers according to Accounting Standards Codification (“ASC”) Topic 606, Revenue from Contracts with Customers To determine revenue recognition for arrangements that the Company determines are within the scope of ASC 606, the Company performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the Company satisfies a performance obligation. The Company only applies the five-step model to contracts when it is probable that the Company will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, once the contract is determined to be within the scope of ASC 606, the Company assesses the goods or services promised within each contract and determines those that are performance obligations, and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation based on relative fair values, when (or as) the performance obligation is satisfied. The Company recognizes revenue from its license and collaboration arrangements and royalties. The terms of the arrangements generally include payment to the Company of one or more of the following: non-refundable, upfront license fees, development, regulatory and commercial milestone payments, and royalties on net sales of licensed products. License of intellectual property If the license to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenue from non-refundable, upfront fees allocated to the license when the license is transferred to the customer and the customer is able to use and benefit from the license. For licenses that are bundled with other promises, such as transfer of related materials, process and know-how, the Company utilizes judgement to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time. Under the Company’s license agreements, the nature of the combined performance obligation is the granting of licenses to the customers as the other promises are not separately identifiable in the context of the arrangement. Since the Company grants the license to a customer as it exists at the point of transfer, and is not involved in any future development or commercialization of the products related to the license, the nature of the license is a right to use the Company’s intellectual property as transferred. As such, the Company recognizes revenue related to the combined performance obligation upon completion of the delivery of the related materials, process and know-how (i.e., at a point in time). Milestone payments At the inception of each arrangement that includes development and regulatory milestone payments, the Company evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price. ASC 606 suggests two alternatives to use when estimating the amount of variable consideration: the expected value method and the most likely amount method. Under the expected value method, an entity considers the sum of probability-weighted amounts in a range of possible consideration amounts. Under the most likely amount method, an entity considers the single most likely amount in a range of possible consideration amounts. The Company uses the most likely amount method for development and regulatory milestone payments. If it is probable that a significant cumulative revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the control of the Company or the licensee, such as regulatory approvals, are not considered probable of being achieved until those approvals are received. The transaction price is then allocated to each performance obligation on a relative stand-alone selling price basis. The Company recognizes revenue as or when the performance obligations under the contract are satisfied. At the end of each subsequent reporting period, the Company re-evaluates the probability or achievement of each such milestone and any related constraint, and if necessary, adjusts its estimates of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect revenue and earnings in the period of adjustment. Royalties For arrangements that include sales-based royalties, including milestone payments based on the level of sales, and the license is deemed to be the predominant item to which the royalties relate, the Company recognizes revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). Upfront payments and fees are recorded as deferred revenue upon receipt or when due and may require deferral of revenue recognition to a future period until the Company performs its obligations under these arrangements. Amounts payable to the Company are recorded as accounts receivable when the Company’s right to consideration is unconditional. The Company does not assess whether a contract has a significant financing component if the expectation at contract inception is such that the period between payment by the customer and the transfer of the promised goods or services to the customer will be one year or less. Sale of Future Revenue Streams The Company has sold its rights to receive certain milestones and royalties on product sales. In the circumstance where the Company has sold its rights to future milestones and royalties under a license agreement and also maintains limited continuing involvement in the arrangement (but not significant continuing involvement in the generation of the cash flows that are due to the purchaser), the Company defers recognition of the proceeds it receives for the sale of milestone or royalty streams and recognizes such unearned revenue as revenue under units-of-revenue method over the life of the underlying license agreement. Under the units-of-revenue method, amortization for a reporting period is calculated by computing a ratio of the proceeds received from the purchaser to the total payments expected to be made to the purchaser over the term of the agreement, and then applying that ratio to the period’s cash payment. Estimating the total payments expected to be received by the purchaser over the term of such arrangements requires management to use subjective estimates and assumptions. Changes to the Company’s estimate of the payments expected to be made to the purchaser over the term of such arrangements could have a material effect on the amount of revenues recognized in any particular period. Stock-Based Compensation The Company recognizes compensation expense for all stock-based payment awards made to the Company’s employees, consultants and directors that are expected to vest based on estimated fair values. The valuation of stock option awards is determined at the date of grant using the Black-Scholes Option Pricing Model (the “Black-Scholes Model”). The Black-Scholes Model requires inputs such as the expected term of the option, expected volatility and risk-free interest rate. To establish an estimate of expected term, the Company considers the vesting period and contractual period of the award and its historical experience of stock option exercises, post-vesting cancellations and volatility. The estimate of expected volatility is based on the Company’s historical volatility. The risk-free rate is based on the yield available on United States Treasury zero-coupon issues corresponding to the expected term of the award. The Company records forfeitures when they occur. The Company records compensation expense for service-based awards on a straight-line basis over the requisite service period, which is generally the vesting period of the award, or to the date on which retirement eligibility is achieved, if shorter. Equity Securities The Company received shares of common stock from Rezolute, Inc. (“Rezolute”) (Note 4). Equity investments in Rezolute are classified in the condensed consolidated balance sheets as equity securities. The equity securities are measured at fair value, with changes in fair value recorded in the other income (expense), net line item of the condensed consolidated statement of operations and comprehensive loss at each reporting period. The Company remeasures its equity investments at each reporting period until such time that the investment is sold or disposed of. If the Company sells an investment, any realized gains and losses on the sale of the securities will be recognized in the condensed consolidated statement of operations and comprehensive loss in the period of sale. In October 2020, Rezolute completed a 1:50 Purchase of Rights to Future Milestones and Royalties The Company has purchased rights to receive a portion of certain future developmental, regulatory and commercial sales milestones, royalties and option fees on sales of products currently in clinical development. The Company acquired such rights from various entities and recorded the amount paid for these rights as long-term royalty receivables (Note 5). In addition, the Company may be obligated to make contingent payments related to certain product development milestones, fees upon exercise of options related to future license products and sales-based milestones. The contingent payments are evaluated whether they are freestanding instruments or embedded derivatives. If freestanding instruments, the contingent payments are measured at fair value at the inception of the arrangement, subject to remeasurement to fair value each reporting period. Any changes in the estimated fair value is recorded in the condensed consolidated statement of operations and comprehensive loss. The Company accounts for milestone and royalty rights related to developmental pipeline products on a non-accrual basis using the cost recovery method. These developmental pipeline products are non-commercialized, non-approved products that require Food and Drug Administration (“FDA”) or other regulatory approval, and thus have uncertain cash flows. The Company is not yet able to reliably forecast future cash flows given their pre-commercial stages of development. The related receivable balance is classified as noncurrent since no payments are probable to be received in the near term. Under the cost recovery method, any milestone or royalty payment received is recorded as a direct reduction of the recorded receivable balance. When the recorded receivable balance has been fully collected, any additional amounts collected are recognized as revenue. The Company reviews public information on clinical trials, press releases and updates from its partners regularly to identify any impairment indicators or changes in expected recoverability of the long-term royalty receivable asset. If an impairment indicator is identified, and the Company determines expected future cash flows discounted to the current period are less than the carrying value of the asset, the Company will record impairment. The impairment will be recognized by reducing the financial asset to an amount that represents the present value of the most recent estimate of future cash flows. No impairment indicators were identified, and no impairment was recorded as of June 30, 2021 and December 31, 2020. Leases The Company leases its headquarters office space in Emeryville, California. The Company determines the initial classification and measurement of its right-of-use assets and lease liabilities at the lease commencement date and thereafter if modified. The lease term includes any renewal options and termination options that the Company is reasonably certain to exercise. The present value of lease payments is determined by using the interest rate implicit in the lease, if that rate is readily determinable; otherwise, the Company uses its incremental borrowing rate. The incremental borrowing rate is determined by using the rate of interest that the Company would pay to borrow on a collateralized basis an amount equal to the lease payments for a similar term and in a similar economic environment. The Company built its incremental borrowing rate starting with the interest rate on its fully collateralized debt and then adjusted it for lease term length. Rent expense for operating leases is recognized on a straight-line basis, unless the right-of-use asset has been impaired, over the reasonably assured lease term based on the total lease payments and is included in operating expenses in the condensed consolidated statements of operations and comprehensive loss. If an operating lease were to reflect impairment, the Company will recognize the amortization of the right-of-use asset on a straight-line basis over the remaining lease term with rent expense still included in operating expenses in the condensed consolidated statements of operations and comprehensive loss. For all leases, rent payments that are based on a fixed index or rate at the lease commencement date are included in the measurement of lease assets and lease liabilities at the lease commencement date. The Company has elected the practical expedient to not separate lease and non-lease components. The Company’s non-lease components are primarily related to property maintenance, which varies based on future outcomes, and thus is recognized in rent expense when incurred. Income Taxes The Company accounts for income taxes using the liability method under which deferred tax assets and liabilities are determined based on differences between financial reporting and tax bases of assets and liabilities and are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse. Valuation allowances are established when necessary to reduce deferred tax assets to the amount which is more likely than not to be realizable. The recognition, derecognition and measurement of a tax position is based on management’s best judgment given the facts, circumstances and information available at each reporting date. The Company’s policy is to recognize interest and penalties related to the underpayment of income taxes as a component of income tax expense. To date, there have been no interest or penalties charged in relation to the unrecognized tax benefits. Net Loss per Share Attributable to Common Stockholders The Company calculates basic and diluted loss per share attributable to common stockholders using the two-class method. The Company’s convertible Series X and Series Y preferred stocks participate in any dividends declared by the Company on its common stock and are therefore considered to be participating securities. The Company’s Series A and Series B Preferred Stock do not participate in any dividends or distribution by the Company on its common stock and are therefore not considered to be participating securities. Under the two-class method, net income, as adjusted for any accumulated dividends on Series A and Series B Preferred Stock for the period and any deemed dividends related to beneficial conversion features on convertible preferred stock, if applicable, is allocated to each class of common stock and participating security as if all of the net income for the period had been distributed. Undistributed earnings allocated to participating securities are subtracted from net income in determining net income attributable to common stockholders. During periods of loss, the Company allocates no loss to participating securities because they have no contractual obligation to share in the losses of the Company. Basic net loss per share attributable to common stockholders is then calculated by dividing the net loss attributable to common stockholders by the weighted average number of shares of common stock outstanding during the period. All participating securities are excluded from the basic weighted average common shares outstanding. Diluted net loss per share attributable to common stockholders is based on the weighted average number of shares outstanding during the period, adjusted to include the assumed exercise of certain stock options and warrants for common stock. The calculation of diluted net loss per share attributable to common stockholders requires that, to the extent the average market price of the underlying shares for the reporting period exceeds the exercise price of any outstanding options or warrants, the presumed exercise of such securities are dilutive to net loss per share attributable to common stockholders for the period. Adjustments to the denominator are required to reflect the related dilutive shares. The Company’s Series A and Series B Preferred Stock become convertible upon the occurrence of specific events other than a change in the Company’s share price and therefore, are not included in the diluted shares until the contingency is resolved. Concentration of Risk Cash and receivables are financial instruments which potentially subject the Company to concentrations of credit risk, as well as liquidity risk. The Company monitors the creditworthiness of its customers to which it grants credit terms in the normal course of business but does not generally require collateral on receivables. For the three months ended June 30, 2021, two partners represented 55% and 42% of total revenues. For the six months ended June 30, 2021, two partners represented 57% and 39% of total revenues. For the three months ended June 30, 2020, one partner represented 88% of total revenues. For the six months ended June 30, 2020, two partners represented 56% and 40% of total revenues. As of December 31, 2020, one partner represented 100% of the trade receivables, net balance. As of June 30, 2021, the Company had no trade receivables, net balance. Comprehensive Loss Comprehensive loss is comprised of two components: net loss and other comprehensive (loss) income. Other comprehensive (loss) income refers to gains and losses that under U.S. GAAP are recorded as an element of stockholders’ equity but are excluded from net loss. The Company did not record any transactions within other comprehensive (loss) income in the periods presented and, therefore, the net loss and comprehensive loss were the same for all periods presented. Accounting Pronouncements Recently Adopted In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. In August 2020, the FASB issued ASU 2020-06, Debt – Debt with Conversion and Other Options (Subtopic 470-20) and Derivative and Hedging – Contracts in Entity’s Own Equity (Subtopic 815-40). In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting Recent Accounting Pronouncements In June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments In May 2021, the FASB issued ASU 2021-04, Earnings Per Share (Topic 260), Debt—Modifications and Extinguishments (Subtopic 470-50), Compensation—Stock Compensation (Topic 718), and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40): Issuer’s Accounting for Certain Modifications or Exchanges of Freestanding Equity-Classified Written Call Options ​

Condensed Consolidated Financia

Condensed Consolidated Financial Statements Details	6 Months Ended
	Jun. 30, 2021
Condensed Consolidated Financial Statements Details
Condensed Consolidated Financial Statements Details	3. Condensed Consolidated Financial Statements Details Equity Securities As of June 30, 2021 and December 31, 2020, equity securities consisted of an investment in Rezolute’s common stock of $2.3 million and $1.7 million, respectively (Note 4). For the three and six months ended June 30, 2021, the Company recognized a gain of $1.3 million and $0.6 million, respectively, due to the change in fair value of its investment in Rezolute’s common stock in the other income (expense), net line item of the condensed consolidated statements of operations and comprehensive loss. For the three and six months ended June 30, 2020, the Company recognized a gain of $0.1 million and a loss of $0.2 million, respectively. Accrued and Other Liabilities Accrued and other liabilities consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, ​ December 31, ​ 2021 2020 Accrued legal and accounting fees ​ $ 454 ​ $ 351 Accrued incentive compensation ​ ​ 466 ​ ​ 71 Accrued payroll and other ​ 139 ​ 220 Total ​ $ 1,059 ​ $ 642 ​ Net Loss Per Share Attributable to Common Stockholders The following is a reconciliation of the numerator (net loss) and the denominator (number of shares) used in the calculation of basic and diluted net loss per share attributable to common stockholders (in thousands, except per share amounts): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, ​ Six Months Ended June 30, ​ 2021 2020 2021 2020 Numerator ​ ​ ​ ​ Net loss ​ $ (2,237) ​ $ (3,533) ​ $ (9,610) ​ $ (8,291) Less: Series A accumulated dividends ​ (530) ​ — ​ (1,061) ​ ​ — Less: Series B accumulated dividends ​ (763) ​ — ​ (763) ​ ​ — Net loss available to common stockholders, basic and diluted ​ $ (3,530) ​ $ (3,533) ​ $ (11,434) ​ $ (8,291) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Denominator ​ ​ ​ ​ ​ ​ ​ ​ Weighted average shares used in computing basic and diluted net loss per share available to common stockholders ​ 11,285 ​ 10,824 ​ 11,263 ​ 10,292 Basic and diluted net loss per share of common stock ​ $ (0.31) ​ $ (0.33) ​ $ (1.02) ​ $ (0.81) ​ Potentially dilutive securities are excluded from the calculation of diluted net loss per share available to common stockholders if their inclusion is anti-dilutive. The following table shows the weighted-average outstanding securities considered anti-dilutive and therefore excluded from the computation of diluted net loss per share attributable to common stockholders (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, ​ Six Months Ended June 30, ​ 2021 2020 2021 2020 Convertible preferred stock ​ 5,003 ​ 5,196 ​ 5,003 ​ 5,726 Common stock options 377 564 318 ​ 578 Warrants for common stock 5 19 5 ​ 19 Total 5,385 5,779 5,326 6,323 ​

Licensing and Other Arrangement

Licensing and Other Arrangements	6 Months Ended
	Jun. 30, 2021
Licensing and Other Arrangements
Licensing and Other Arrangements	4. Licensing and Other Arrangements Novartis International – Anti-TGFβ Antibody (NIS793) On September 30, 2015, the Company and Novartis International Pharmaceutical Ltd. (“Novartis International”) entered into a license agreement (the “Anti-TGFβ Antibody License Agreement”) under which the Company granted Novartis International an exclusive, world-wide, royalty-bearing license to the Company’s anti-transforming growth factor beta (“TGFβ”) antibody program (now “NIS793”). Under the terms of the Anti-TGFβ Antibody License Agreement, Novartis International has worldwide rights to NIS793 and is responsible for the development and commercialization of antibodies and products containing antibodies arising from NIS793. Unless terminated earlier, the Anti-TGFβ Antibody License Agreement will remain in effect, on a country-by-country and product-by-product basis, until Novartis International’s royalty obligations end. The Anti-TGFβ Antibody License Agreement contains customary termination rights relating to material breach by either party. Novartis International also has a unilateral right to terminate the Anti-TGFβ Antibody License Agreement on an antibody-by-antibody and country-by-country basis or in its entirety on one hundred eighty days’ notice. The Company concluded that there were multiple promised goods and services under the Anti-TGFβ Antibody License Agreement, including the transfer of license, regulatory services and transfer of materials, process and know-how, which were determined to represent one combined performance obligation. The Company recognized the entire upfront payment of $37.0 million as revenue in the consolidated statement of comprehensive loss in 2015 as it had completed its performance obligations as of December 31, 2015 The Company is eligible to receive up to a total of $480.0 million in development, regulatory and commercial milestones under the Anti-TGFβ Antibody License Agreement. During the year ended December 31, 2017, Novartis International achieved a clinical development milestone pursuant to the Anti-TGFβ Antibody License Agreement, and as a result, the Company earned a $10.0 million milestone payment which was recognized as license fees in the consolidated statement of operations and comprehensive loss. The Company concluded that the development and regulatory milestone payments are solely dependent on Novartis International’s performance and achievement of the specified events. The Company determined that it is not probable that a significant cumulative revenue reversal will not occur in future periods for these future payments. Therefore, the remaining development and regulatory milestones are fully constrained and excluded from the transaction price until the respective milestone is achieved. Any consideration related to commercial milestones (including royalties) will be recognized when the related sales occur as they were determined to relate predominantly to the licenses granted to Novartis International and therefore, have also been excluded from the transaction price. At the end of each reporting period, the Company will update its assessment of whether an estimate of variable consideration is constrained and update the estimated transaction price accordingly. The Company is also eligible to receive royalties on sales of licensed products, which are tiered based on sales levels and range from a mid single-digit percentage rate to up to a low double-digit percentage rate. Novartis International’s obligation to pay royalties with respect to a particular product and country will continue for the longer of the date of expiration of the last valid patent claim covering the product in that country, or ten years from the date of the first commercial sale of the product in that country. On October 21, 2020, the first patient was dosed in Novartis International's NIS793 Phase 2 clinical trial and the Company earned a $25.0 million milestone payment. As specified under the terms of the Anti-TGFβ Antibody License Agreement, the Company received $17.7 million in cash and the remaining balance of $7.3 million was recognized as a reduction to the Company's debt obligation to Novartis. The Company is eligible to receive up to a total of $445.0 million in the remaining development, regulatory and commercial milestones under the Anti-TGFβ Antibody License Agreement. As of June 30, 2021 and December 31, 2020, there were no contract assets or contract liabilities related to this agreement. None of the costs to obtain or fulfill the contract were capitalized. No revenue was recognized for the three and six months ended June 30, 2021 and 2020. Novartis – Gevokizumab (VPM087) and IL-1 Beta On August 24, 2017, the Company and Novartis Pharma AG (“Novartis”) entered into a license agreement (the “Gevokizumab License Agreement”) under which the Company granted to Novartis an exclusive, worldwide, royalty-bearing license to gevokizumab (“VPM087”), a novel anti-Interleukin-1 (“IL-1”) beta allosteric monoclonal antibody and related know-how and patents (altogether, the “XOMA IP”). Under the terms of the Gevokizumab License Agreement, Novartis is solely responsible for the development and commercialization of VPM087 and products containing VPM087. On August 24, 2017, pursuant to a separate agreement (the “IL-1 Target License Agreement”), the Company granted to Novartis non-exclusive licenses to its intellectual property covering the use of IL-1 beta targeting antibodies in the treatment and prevention of cardiovascular disease and other diseases and conditions, and an option to obtain an exclusive license (the “Exclusivity Option”) to such intellectual property for the treatment and prevention of cardiovascular disease. Under the Gevokizumab License Agreement, the Company received total consideration of $30.0 million for the license and rights granted to Novartis. Of the total consideration, $15.7 million was paid in cash and $14.3 million (equal to €12.0 million) was paid by Novartis Institutes for BioMedical Research, Inc. (“NIBR”), on behalf of the Company, to settle the Company’s outstanding debt with Les Laboratories Servier (“Servier”) (the “Servier Loan”). In addition, NIBR extended the maturity date on the Company’s debt to Novartis. The Company also received $5.0 million cash related to the sale of 539,131 shares of the Company’s common stock, at a purchase price of $9.2742 per share. The fair market value of the common stock issued to Novartis was $4.8 million, based on the closing stock price of $8.93 per share on August 24, 2017, resulting in a $0.2 million premium paid to the Company. Based on the achievement of pre-specified criteria, the Company is eligible to receive up to $438.0 million in development, regulatory and commercial milestones under the Gevokizumab License Agreement. The Company is also eligible to receive royalties on sales of licensed products, which are tiered based on sales levels and range from the high single-digits to mid-teens. Under the IL-1 Target License Agreement, the Company received an upfront cash payment of $10.0 million and is eligible to receive low single-digit royalties on canakinumab sales in cardiovascular indications covered by the Company’s patents. Should Novartis exercise the Exclusivity Option, the royalties on canakinumab sales will increase to the mid single-digits. Unless terminated earlier, the Gevokizumab License Agreement and IL-1 Target License Agreement will remain in effect, on a country-by-country and product-by-product basis, until Novartis’ royalty obligations end. The two agreements contain customary termination rights relating to material breach by either party. Novartis also has a unilateral right to terminate the Gevokizumab License Agreement on a product-by-product and country-by-country basis or in its entirety on six months’ prior written notice to the Company. Under the IL-1 Target License Agreement, Novartis has a unilateral right to terminate the agreement on a product-by-product and country-by-country basis or in its entirety upon a prior written notice. The Gevokizumab License Agreement and IL-1 Target License Agreement were accounted for as one arrangement because they were entered into at the same time in contemplation of each other. The Company concluded that there are multiple promised goods and services under the combined arrangement, including the transfer of license to IL-1 beta targeting antibodies, and the transfer of license, know-how, process, materials and inventory related to the VPM087 antibody, which were determined to represent two distinct performance obligations. The Company determined that the Exclusivity Option is not an option with material right because the upfront payments to the Company were not negotiated to provide an incremental discount for the future additional royalties upon exercise of the Exclusivity Option. Therefore, the Company concluded that the Exclusivity Option is not a performance obligation. The additional royalties will be recognized as revenue when, and if, Novartis exercises its option because the Company has no further performance obligations at that point. At the inception of the arrangement, the Company determined that the transaction price under the arrangement was $40.2 million, which consisted of the $25.7 million upfront cash payments, the $14.3 million Servier Loan payoff and the $0.2 million premium on the sale of the common stock. The transaction price was allocated to the two performance obligations based on their standalone selling prices. The Company determined that the nature of the two performance obligations is the right to use the licenses as they exist at the point of transfer, which occurred when the transfer of materials, process and know-how, and filings to regulatory authority were completed. During the year ended December 31, 2017, the Company recognized the entire transaction price of $40.2 million as revenue upon completion of the delivery of the licenses and related materials, process and know-how and filings to regulatory authority. The Company concluded that the development and regulatory milestone payments are solely dependent on Novartis’ performance and achievement of specified events. The Company determined that it is not probable that a significant cumulative revenue reversal will not occur in future periods for these future payments. Therefore, the development and regulatory milestones are fully constrained and excluded from the transaction price until the respective milestone is achieved. Any consideration related to commercial milestones (including royalties) will be recognized when the related sales occur as they were determined to relate predominantly to the licenses granted to Novartis and therefore, have also been excluded from the transaction price. At the end of each reporting period, the Company will update its assessment of whether an estimate of variable consideration is constrained and update the estimated transaction price accordingly. As of June 30, 2021 and December 31, 2020, there were no contract assets or contract liabilities related to this arrangement. None of the costs to obtain or fulfill the contract were capitalized. No revenue was recognized for the three and six months ended June 30, 2021 and 2020. Takeda On November 1, 2006, the Company entered into a collaboration agreement with Takeda Pharmaceutical Company Limited (“Takeda”) (the “Takeda Collaboration Agreement”) under which the Company agreed to discover and optimize therapeutic antibodies against multiple targets selected by Takeda. Under the terms of the Takeda Collaboration Agreement, the Company may receive additional milestone payments aggregating up to $19.0 million relating to TAK-079 (mezagitamab) and low single-digit royalties on future sales of all products subject to this license. The Company’s right to milestone payments expires on the later of the receipt of payment from Takeda of the last amount to be paid under the agreement or the cessation by Takeda of all research and development activities with respect to all program antibodies, collaboration targets or collaboration products. The Company’s right to royalties expires on the later of 13.5 years from the first commercial sale of each royalty-bearing discovery product or the expiration of the last-to-expire licensed patent (or 12 years from first commercial sale if there is significant generic competition post patent-expiration). In February 2009, the Company expanded the existing collaboration to provide Takeda with access to multiple antibody technologies, including a suite of research and development technologies and integrated information and data management systems. The Company may receive milestones of up to $3.3 million per discovery product candidate and low single-digit royalties on future sales of all antibody products subject to this license. The Company’s right to milestone payments expires on the later of the receipt of payment from Takeda of the last amount to be paid under the agreement or the cessation by Takeda of all research and development activities with respect to all program antibodies, collaboration targets or collaboration products. The Company’s right to royalties expires on the later of 10 years from the first commercial sale of such royalty-bearing discovery product or the expiration of the last-to-expire licensed patent. On November 16, 2020, the first patient was dosed in Takeda’s Phase 2 study of mezagitamab, and the Company earned a $2.0 million milestone payment from Takeda. As of June 30, 2021 and December 31, 2020, there were no contract assets or contract liabilities related to this arrangement. None of the costs to obtain or fulfill the contract were capitalized. No revenue was recognized for the three and six months ended June 30, 2021 and 2020. Rezolute On December 6, 2017, the Company entered into a license agreement with Rezolute pursuant to which the Company granted an exclusive global license to Rezolute to develop and commercialize X358 (now “RZ358”) products for all indications. The Company and Rezolute also entered into a common stock purchase agreement pursuant to which Rezolute agreed to issue to the Company, as consideration for receiving the license for RZ358, a certain number of its common stock related to its future financing activities. Under the terms of the license agreement, Rezolute is responsible for all development, regulatory, manufacturing and commercialization activities associated with RZ358 and is required to make certain development, regulatory and commercial milestone payments to the Company of up to $232.0 million in the aggregate based on the achievement of pre-specified criteria. Under the license agreement, the Company is also eligible to receive royalties ranging from the high single-digits to the mid-teens based upon annual net sales of any commercial product incorporating RZ358. Rezolute is obligated to take customary steps to advance RZ358, including using diligent efforts to commence the next clinical study for RZ358 by a certain deadline and to meet certain spending requirements on an annual basis for the program until a marketing approval application for RZ358 is accepted by the FDA. Rezolute’s obligation to pay royalties with respect to a particular RZ358 product and country will continue for the longer of the date of expiration of the last valid patent claim covering the product in that country, or twelve years from the date of the first commercial sale of the product in that country. Rezolute’s future royalty obligations in the United States will be reduced by 20% if the manufacture, use or sale of a licensed product is not covered by a valid XOMA patent claim, until such a claim is issued. Pursuant to the license agreement, XOMA is eligible to receive a low single-digit royalty on sales of Rezolute’s other non-RZ358 products from its current programs. Rezolute’s obligation to pay royalties with respect to a particular Rezolute product and country will continue for the longer of twelve years from the date of the first commercial sale of the product in that country or for so long as Rezolute or its licensee is selling such product in such country, provided that any such licensee royalty will terminate upon the termination of the licensee’s obligation to make payments to Rezolute based on sales of such product in such country. The license agreement contains customary termination rights relating to material breach by either party. Rezolute also has a unilateral right to terminate the license agreement in its entirety on ninety days’ notice at any time. The Company has the right to terminate the license agreement if Rezolute challenges the licensed patents. No consideration was exchanged upon execution of the arrangement. In consideration for receiving the license for RZ358, Rezolute agreed to issue shares of its common stock and pay cash to the Company upon the occurrence of Rezolute’s financing activities. The license agreement was subsequently amended in 2018, 2019 and 2020. Pursuant to the terms of the license agreement as amended, the Company received a total of $6.0 million upon Rezolute’s achievement of financing activities and $8.5 million in installment payments through October 2020. The Company also received 8,093,010 shares (pre-split shares) of Rezolute’s common stock. During the quarter ended December 31, 2020, Rezolute completed a 1:50 As of June 30, 2021 and December 31, 2020, there were no contract assets or contract liabilities related to this arrangement. None of the costs to obtain or fulfill the contract were capitalized. No revenue was recognized for the three and six months ended June 30, 2021 and 2020. The Company reassessed the development and regulatory milestones and concluded that such variable consideration is fully constrained and excluded from the transaction price as of June 30, 2021 and December 31, 2020. Janssen Biotech The Company and Janssen Biotech, Inc. (“Janssen”) were parties to a license agreement which was terminated in 2017. In August 2019, the Company and Janssen entered into a new agreement pursuant to which the Company granted a non-exclusive license to Janssen to develop and commercialize certain drug candidates under the XOMA patents and know-how. Under the new agreement, Janssen made a one-time payment of $2.5 million to XOMA. Additionally, for each drug candidate, the Company is entitled to receive milestone payments of up to $3.0 million upon Janssen’s achievement of certain clinical development and regulatory approval events. Additional milestones may be due for drug candidates which are the subject of multiple clinical trials. Upon commercialization, the Company is eligible to receive 0.75% royalty on net sales of each product. Janssen’s obligation to pay royalties with respect to a particular product and country will continue until the eighth-year and sixth-month anniversary of the first commercial sale of the product in such country. The new agreement will remain in effect unless terminated by mutual written agreement of the parties. The Company concluded that the new agreement should be accounted for separately from any prior arrangements with Janssen and that the license grant is the only performance obligation under the new agreement. The Company recognized the entire one-time payment of $2.5 million as revenue in the consolidated statement of operations and comprehensive loss for the year ended December 31, 2019 as it had completed its performance obligation. The Company concluded that the development and regulatory milestone payments are solely dependent on Janssen’s performance and achievement of specified events and thus it is not probable that a significant cumulative revenue reversal will not occur in future periods for these future payments. Therefore, the development and regulatory milestones are fully constrained and excluded from the transaction price until the respective milestone is achieved. Any consideration related to royalties will be recognized when the related sales occur as they were determined to relate predominantly to the license granted to Janssen and therefore, have also been excluded from the transaction price. At the end of each reporting period, the Company will update its assessment of whether an estimate of variable consideration is constrained and update the estimated transaction price accordingly. In May 2021, the Company earned a $0.5 million milestone from Janssen, upon dosing of the first patient in a Phase 3 clinical trial evaluating one of Janssen’s biologic assets. As of June 30, 2021 and December 31, 2020, there were no contract assets or contract liabilities related to this arrangement. None of the costs to obtain or fulfill the contract were capitalized. The Company recognized milestone revenue of $0.5 million for the three and six months ended June 30, 2021. No revenue was recognized for the three and six months ended June 30, 2020. Affimed The Company and Affimed N.V. (“Affimed”) were parties to a license agreement which was subsequently terminated. In April 2021, the Company and Affimed entered into a new agreement, under which the Company is eligible to receive payments from Affimed on potential future commercial sales related to three innate cell engager (“ICE”) molecules and any product candidates containing the ICE molecules. Additionally, the Company is eligible to receive a milestone for each program upon each product candidate achieving marketing approval. The Company concluded that the commercial milestone payments are solely dependent on Affimed’s performance and achievement of specified events. The Company determined that it is not probable that a significant cumulative revenue reversal will not occur in future periods for these future payments. Therefore, the commercial milestones are fully constrained and excluded from the transaction price until the respective milestone is achieved. Any consideration related to commercial milestones (including royalties) will be recognized when the related approvals occur and therefore, have also been excluded from the transaction price. At the end of each reporting period, the Company will update its assessment of whether an estimate of variable consideration is constrained and update the estimated transaction price accordingly. As of June 30, 2021, there were no contract assets or contract liabilities NIAID Prior to the sale of the Company’s biodefense business in 2016, the Company performed services under a $64.8 million multiple-year contract funded with federal funds from NIAID (Contract No. HHSN272200800028C), for development of anti-botulinum antibody product candidates. The contract work was being performed on a cost-plus fixed fee basis over a three-year period. The Company recognized revenue under the arrangement as the services were performed on a proportional performance basis. Consistent with the Company’s other contracts with the U.S. government, invoices were provisional until finalized. The Company operated under provisional rates from 2010 through 2015, subject to adjustment based on actual rates upon agreement with the government. In 2014, upon completion of NIAID’s review of hours and external expenses, XOMA agreed to exclude certain hours and external expenses resulting in a $0.4 million receivable and $0.8 million deferred revenue balances. As of December 31, 2017, the Company wrote off the $0.4 million receivable from NIAID as the likelihood of collection was remote. In October of 2019, NIH, which includes NIAID, notified the Company that it engaged KPMG to perform an audit of the Company’s incurred cost submissions for 2013, 2014 and 2015. The KPMG testing procedures were completed in December 2020. As a result, the Company recognized $1.4 million as estimated refund liabilities owed to NIH on the consolidated balance sheet as of December 31, 2020. The additional $0.6 million liability was recognized as a reduction of revenue from contracts with customers in the consolidated statement of operations and comprehensive income (loss) for the year ended December 31, 2020. The audit remains subject to further review by NIH as part of the contract close-out process, which includes finalization of rates for years 2010 through 2015, and the Company may incur a further liability as a result. The Company had $1.4 million as contingent liabilities on the condensed consolidated balance sheets as of June 30, 2021 and December 31, 2020, related to these matters. Sale of Future Revenue Streams On December 21, 2016, the Company entered into two royalty interest sale agreements (together, the “Royalty Sale Agreements”) with HCRP. Under the first Royalty Sale Agreement, the Company sold its right to receive milestone payments and royalties on future sales of products subject to a License Agreement, dated August 18, 2005, between XOMA and Wyeth Pharmaceuticals (subsequently acquired by Pfizer, Inc. (“Pfizer”)) for an upfront cash payment of $6.5 million, plus potential additional payments totaling $4.0 million in the event three specified net sales milestones were met in 2017, 2018 and 2019. Based on actual sales, 2017, 2018, and 2019 sales milestones were not achieved. Under the second Royalty Sale Agreement entered into in December 2016, the Company sold its right to receive certain royalties under an Amended and Restated License Agreement dated October 27, 2006 between XOMA and Dyax Corp. for a cash payment of $11.5 million. The Company classified the proceeds received from HCRP as unearned revenue, to be recognized as revenue under units-of-revenue method over the life of the license agreements because of the Company’s limited continuing involvement in the Acquisition Agreements. Such limited continuing involvement is related to the Company’s undertaking to cooperate with HCRP in the event of litigation or a dispute related to the license agreements. Because the transaction was structured as a non-cancellable sale, the Company does not have significant continuing involvement in the generation of the cash flows due to HCRP and there are no guaranteed rates of return to HCRP, the Company recorded the total proceeds of $18.0 million as unearned revenue recognized under units-of-revenue method. The Company allocated the total proceeds between the two Royalty Sale Agreements based on the relative fair value of expected payments to be made to HCRP under the license agreements. The unearned revenue is being recognized as revenue over the life of the underlying license agreements under the "units-of-revenue" method. Under this method, amortization for a reporting period is calculated by computing a ratio of the allocated proceeds received from HCRP to the payments expected to be made by the licensees to HCRP over the term of the Acquisition Agreements, and then applying that ratio to the period’s cash payment. During the third quarter of 2018, the Shire product underlying the Dyax Corp. license agreement was approved, and the Company began recognizing revenue under the units-of-revenue method due to sales of the approved product. The Company recognized $0.4 million and $0.7 million as revenue under units-of-revenue method under these arrangements during the three and six months ended June 30, 2021, respectively. The Company recognized $0.4 million and $0.7 million as revenue under units-of-revenue method under these arrangements during the three and six months ended June 30, 2020, respectively. As of June 30, 2021, the Company classified $1.5 million and $12.7 million as current and non-current unearned revenue recognized under units-of-revenue method, respectively. As of December 31, 2020, the current and non-current portion of the remaining unearned revenue recognized under units-of-revenue method was $1.5 million and $13.5 million, respectively.

Royalty Purchase Agreements

Royalty Purchase Agreements	6 Months Ended
	Jun. 30, 2021
Royalty Purchase Agreements
Royalty Purchase Agreements	5. Royalty Purchase Agreements Royalty Purchase Agreement with Agenus, Inc. On September 20, 2018, the Company entered into a royalty purchase agreement (the “Agenus Royalty Purchase Agreement”) with Agenus, Inc., and certain affiliates (collectively, “Agenus”). Under the Agenus Royalty Purchase Agreement, the Company purchased from Agenus the right to receive 33% of the future royalties on six Incyte Europe S.a.r.l. (“Incyte”) immuno-oncology assets, currently in development, due to Agenus from Incyte (net of certain royalties payable by Agenus to a third party) and 10% of all future developmental, regulatory and commercial milestones related to these assets. However, the Company did not have a right to the expected near-term milestone associated with the entry of INCAGN2390 (anti-TIM-3) into its Phase 1 clinical trial. The future royalties due to Agenus from Incyte are based on low single to mid-teen digit percentage of applicable net sales. In addition, the Company purchased from Agenus the right to receive 33% of the future royalties on MK-4830, an immuno-oncology product currently in clinical development, due to Agenus from Merck Sharp & Dohme Corp. (“Merck”) and 10% of all future developmental, regulatory and commercial milestones related to this asset. The future royalties due to Agenus from Merck are based on low single-digit percentage of applicable net sales. Pursuant to the Agenus Royalty Purchase Agreement, the Company’s share in future potential development, regulatory and commercial milestones is up to $59.5 million. There is no limit on the amount of future royalties on sales that the Company may receive under the agreements. Under the terms of the Agenus Royalty Purchase Agreement, the Company paid Agenus $15.0 million. The Company financed $7.5 million of the purchase price with a term loan under its Loan and Security Agreement with Silicon Valley Bank (Note 8). At the inception of the agreement, the Company recorded $15.0 million as long-term royalty receivables in the condensed consolidated balance sheets. In November 2020, MK-4830 advanced into Phase 2 development and Agenus earned a $10.0 million clinical development milestone under its license agreement with Merck, of which the Company earned $1.0 million. In accordance with the cost recovery method, the $1.0 million milestone received was recorded as a direct reduction of the recorded long-term royalty receivable balance. The Company continues to assess that no further payments are probable to be received under this agreement in the near term. Under the cost recovery method, the Company does not expect to recognize any income related to milestones and royalties received until the investment has been fully collected. The Company performed its quarterly impairment assessment and no impairment indicators were identified. Accordingly, no impairment was recorded as of June 30, 2021. Royalty Purchase Agreement with Bioasis Technologies, Inc. On February 25, 2019, the Company entered into a royalty purchase agreement (the “Bioasis Royalty Purchase Agreement”) with Bioasis Technologies, Inc. and certain affiliates (collectively “Bioasis”). Under the Bioasis Royalty Purchase Agreement, the Company purchased potential future milestone and royalty rights from Bioasis for product candidates that are being developed pursuant to a license agreement between Bioasis and Prothena Biosciences Limited. In addition, the Company was granted options to purchase a 1% royalty right on the next two license agreements entered into between Bioasis and third-party licensees subject to certain payments and conditions as well as a right of first negotiation on subsequent Bioasis license agreements with third parties. Upon exercise of the option related to the second license agreement executed by Bioasis, the Company may be obligated to pay up to $0.3 million per licensed product. Upon exercise of the option related to the third license agreement executed by Bioasis, the Company may be obligated to pay up to $0.4 million per licensed product. Under the terms of the Bioasis Royalty Purchase Agreement, the Company paid $0.3 million and will make contingent future cash payments of up to $0.2 million to Bioasis as the licensed product candidates reach certain development milestones (the “Bioasis Contingent Consideration”). At the inception of the agreement, the Company recorded $0.4 million as long-term royalty receivables in its condensed consolidated balance sheet, including the estimated fair value of the Bioasis Contingent Consideration of $0.1 million. Future changes in the estimated fair value of the contingent consideration will be recognized in the other income (expense), net line item of the condensed consolidated statement of operations and comprehensive loss. As of June 30, 2021, there was no change in the fair value of the contingent consideration from its initial value and no amounts were paid during the three and six months ended June 30, 2021. The Company continues to assess that no payments are probable to be received under this agreement in the near term. Under the cost recovery method, the Company does not expect to recognize any income related to milestones and royalties received until the investment has been fully collected. The Company performed its quarterly impairment assessment and no impairment indicators were identified. Accordingly, no impairment was recorded as of June 30, 2021. On November 2, 2020, the Company entered into another royalty purchase agreement (the “Second Bioasis Royalty Purchase Agreement”) with Bioasis. Under the Second Bioasis Royalty Purchase Agreement, the Company purchased potential future milestone and other payments, and royalty rights from Bioasis for product candidates that are being developed pursuant to a research collaboration and license agreement between Bioasis and Chiesi Farmaceutici S.p.A. (“Chiesi”). The Company paid Bioasis $1.2 million upon closing of the Second Bioasis Royalty Purchase Agreement for the purchased rights. At the inception of the Second Bioasis Royalty Purchase Agreement, the Company recorded $1.2 million as long-term royalty receivables in its consolidated balance sheet. The Company continues to assess that no payments are probable to be received under the Second Bioasis Royalty Purchase Agreement in the near term. Under the cost recovery method, the Company does not expect to recognize any income related to milestones and other payments until the investment has been fully collected. The Company performed its quarterly impairment assessment and no impairment indicators were identified. Accordingly, no impairment was recorded as of June 30, 2021. Royalty Purchase Agreement with Aronora, Inc. On April 7, 2019, the Company entered into a royalty purchase agreement (the “Aronora Royalty Purchase Agreement”) with Aronora, Inc. (“Aronora”), which closed on June 26, 2019. Under the Aronora Royalty Purchase Agreement, the Company purchased from Aronora the right to receive future royalties and a portion of upfront, milestone, and option payments (the “Non-Royalties”) related to five anti-thrombotic hematology drug candidates. Three candidates were subject to Aronora’s collaboration with Bayer Pharma AG (“Bayer”) (the “Bayer Products”), including one which was subject to an exclusive license option by Bayer. The Company will receive 100% of future royalties and 10% of future Non-Royalties from these Bayer Products. The other two candidates are unpartnered (the “non-Bayer Products”) for which the Company will receive low single-digit percentage of net sales and 10% of Non-Royalties. The future payment percentage for Non-Royalties will be reduced from 10% to 5% upon the Company’s receipt of two times the total cumulative amount of consideration paid by the Company to Aronora. In July 2020, Bayer elected to not exercise its option on the third Bayer Product and that product is now subject to the same economics as the non-Bayer Products. Under the terms of the Aronora Royalty Purchase Agreement, the Company paid Aronora a $6.0 million upfront payment at the close of the transaction. The Company financed $3.0 million of the upfront payment with a term loan under its Loan and Security Agreement with SVB (Note 8). The Company was required to make a contingent future cash payment of $1.0 million for each of the three Bayer Products that were active on September 1, 2019 (up to a total of $3.0 million, the “Aronora Contingent Consideration”). Pursuant to the Aronora Royalty Purchase Agreement, if the Company receives $250.0 million in cumulative royalties on net sales per product, the Company will be required to pay associated tiered milestone payments to Aronora in an aggregate amount of up to $85.0 million per product (the “Royalty Milestones”). The Royalty Milestones are paid based upon various royalty tiers prior to reaching $250.0 million in cumulative royalties on net sales per product. Royalties per product in excess of $250.0 million are retained by the Company. At the inception of the agreement, the Company recorded $9.0 million as long-term royalty receivables in its condensed consolidated balance sheet, including the estimated fair value of the Aronora Contingent Consideration of $3.0 million. In September 2019, the Company paid the $3.0 million contingent consideration to Aronora. As the Company receives royalties from Aronora for a product, the Company will recognize the liability for future Royalty Milestones for such product when probable and estimable. The Company continues to assess that no payments are probable to be received under this agreement in the near term. Under the cost recovery method, the Company does not expect to recognize any income related to milestones and royalties received until the investment has been fully collected. The Company performed its quarterly impairment assessment and no impairment indicators were identified. Accordingly, no impairment was recorded as of June 30, 2021. Royalty Purchase Agreement with Palobiofarma, S.L. On September 26, 2019, the Company entered into a royalty purchase agreement (the “Palo Royalty Purchase Agreement”) with Palobiofarma, S.L. (“Palo”), a company organized and existing under the laws of Spain. Pursuant to the Palo Royalty Purchase Agreement, the Company acquired the rights to potential royalty payments in low single-digit percentages of aggregate Net Sales (as defined in the Palo Royalty Purchase Agreement) associated with six drug candidates in various clinical development stages, targeting the adenosine pathway with potential applications in solid tumors, non-Hodgkin’s lymphoma, asthma/chronic obstructive pulmonary disease, ulcerative colitis, idiopathic pulmonary fibrosis, lung cancer, psoriasis and nonalcoholic steatohepatitis and other indications (the “Palo Licensed Products”) that are being developed by Palo. Novartis is a development partner on NIR178, one of the Palo Licensed Products, and NIR178 is being developed pursuant to a license agreement between Palo and Novartis. Under the terms of the Palo Royalty Purchase Agreement, the Company paid Palo a $10.0 million payment at the close of the transaction which occurred simultaneously upon parties’ entry into the Palo Royalty Purchase Agreement on September 26, 2019. The Company financed $5.0 million of the payment with a term loan under its Loan and Security Agreement with SVB (Note 8). At the inception of the agreement, the Company recorded $10.0 million as long-term royalty receivables in its condensed consolidated balance sheet. The Company continues to assess that no payments are probable to be received under this agreement in the near term. Under the cost recovery method, the Company does not expect to recognize any income related to royalties received until the investment has been fully collected. The Company performed its quarterly impairment assessment and no impairment indicators were identified. Accordingly, no impairment was recorded as of June 30, 2021. Royalty Purchase Agreement with Viracta Therapeutics, Inc. On March 22, 2021, the Company entered into a royalty purchase agreement (the “Viracta Royalty Purchase Agreement”) with Viracta Therapeutics, Inc. (“Viracta”). Pursuant to the Viracta Royalty Purchase Agreement, the Company acquired the right to receive future royalties, milestones, and other payments related to two clinical stage drug candidates. The first candidate, DAY101 (pan-RAF kinase inhibitor), is being developed by Day One Biopharmaceuticals, and the second candidate, vosaroxin (topoisomerase II inhibitor), is being developed by Denovo Biopharma. The Company acquired the right to receive (i) up to $54.0 million in potential milestones, potential royalties on sales, if approved, and other payments related to DAY101, excluding up to $20.0 million consideration retained by Viracta; and (ii) up to $57.0 million in potential regulatory and commercial milestones and high single-digit royalties on sales related to vosaroxin, if approved. At the inception of the Viracta Royalty Purchase Agreement, the Company recorded $13.5 million as long-term royalty receivables in its condensed consolidated balance sheet. No payments are probable to be received under the Viracta Royalty Purchase Agreement in the near term. Under the cost recovery method, the Company does not expect to recognize any income related to royalties, milestones and other payments until the investment has been fully collected. The Company performed its quarterly impairment assessment and no impairment indicators were identified. Accordingly, no impairment was recorded as of June 30, 2021. The following table summarizes the long-term royalty receivable activities including acquisitions of royalty rights during the six months ended June 30, 2021 (in thousands): ​ ​ ​ ​ Balance at December 31, 2020 $ 34,575 Acquisition of royalty rights: ​ ​ ​ Viracta ​ 13,500 Balance at June 30, 2021 ​ $ 48,075 ​

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2021
Fair Value Measurements
Fair Value Measurements	6. Fair Value Measurements The Company records its financial assets and liabilities at fair value. The carrying amounts of certain of the Company’s financial instruments, including cash, trade receivables, net and accounts payable, approximate their fair value due to their short maturities. Fair value is defined as the exchange price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The accounting guidance for fair value establishes a framework for measuring fair value and a fair value hierarchy that prioritizes the inputs used in valuation techniques. The accounting standard describes a fair value hierarchy based on three levels of inputs, of which the first two are considered observable and the last unobservable, that may be used to measure fair value, which are the following: Level 1 – Observable inputs, such as unadjusted quoted prices in active markets for identical assets or liabilities. Level 2 – Observable inputs, either directly or indirectly, other than quoted prices in active markets for identical assets or liabilities, such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 – Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities; therefore, requiring an entity to develop its own valuation techniques and assumptions. The following tables set forth the Company’s fair value hierarchy for its financial assets and liabilities measured at fair value on a recurring basis as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements at June 30, 2021 Using ​ ​ Quoted Prices in ​ Significant Other ​ Significant ​ ​ ​ ​ ​ Active Markets for ​ Observable ​ Unobservable ​ ​ ​ ​ ​ Identical Assets ​ Inputs ​ Inputs ​ ​ ​ ​ (Level 1) (Level 2) (Level 3) Total Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Equity securities ​ $ 2,310 ​ $ — ​ $ — ​ $ 2,310 Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contingent consideration ​ $ — ​ $ — ​ $ 75 ​ $ 75 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements at December 31, 2020 Using ​ ​ Quoted Prices in ​ Significant Other ​ Significant ​ ​ ​ ​ ​ Active Markets for ​ Observable ​ Unobservable ​ ​ ​ ​ ​ Identical Assets ​ Inputs ​ Inputs ​ ​ ​ ​ (Level 1) (Level 2) (Level 3) Total Assets: ​ ​ ​ ​ ​ ​ ​ ​ Equity securities ​ $ — ​ $ — ​ $ 1,693 ​ $ 1,693 Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contingent consideration ​ $ — ​ $ — ​ $ 75 ​ $ 75 ​ Transfers to and from Levels 1, 2, and 3 are recognized at the end of the reporting period. During the three and six months ended June 30, 2021, the Company’s equity investment in Rezolute’s common stock transferred from Level 3 to Level 1. In reporting periods prior to June 30, 2021, the Company applied an illiquidity discount to the fair value of Rezolute’s common stock due to the lack of trading volume, resulting in classification as Level 3. As of June 30, 2021, there was sufficient and consistent trading volume on the Nasdaq Stock Market to provide an estimate of fair value utilizing quoted prices in an active market for the identical securities as of the reporting date, resulting in classification as Level 1. There were no transfers between levels for the three and six months ended June 30, 2020. Equity Securities The following table reconciles the beginning and ending balance for the Level 3 financial assets recurring fair value measurement for the six months ended June 30, 2021 (in thousands): ​ ​ ​ ​ ​ ​ ​ Six Months Ended ​ ​ June 30, Balance at December 31, 2020 ​ $ 1,693 Change in fair value ​ 617 Transfer out of Level 3 ​ ​ (2,310) Balance at June 30, 2021 ​ $ — ​ The equity securities consisted of an investment in Rezolute’s common stock and are classified on the condensed consolidated balance sheets as current assets as of June 30, 2021, and long-term assets as of December 31, 2020. The reclassification from noncurrent to current assets was due to the equity securities achieving sufficient and consistent trading volume on the Nasdaq Stock Market as of the June 30, 2021 reporting date. The equity securities are revalued each reporting period with changes in fair value recorded in the other income (expense), net line item of the condensed consolidated statements of operations and comprehensive loss. As of December 31, 2020, the Company and its valuation specialist, valued the equity securities using the closing price for Rezolute’s common stock traded on the Nasdaq Stock Market and adjusted for an illiquidity discount. The inputs that were used to calculate the illiquidity discount were based on observable and unobservable estimates and judgments and therefore were classified as a Level 3 fair value measurement. As the Company has the right and option to sell up to 100,000 shares of Rezolute’s common stock back to Rezolute after December 31, 2019 (Note 4), the fair value of the equity securities was determined by dividing the total shares of Rezolute’s common stock held by the Company into two tranches based on the estimated time to a potential liquidity event. ​ As of June 30, 2021, the Company valued the equity securities using the closing price for Rezolute’s common stock traded on the Nasdaq Stock Market. The inputs that were used to calculate the fair value of the equity securities were observable prices in active markets and therefore were classified as a Level 1 fair value measurement. ​ The closing price of Rezolute’s common stock as per the Nasdaq Stock Market was $14.27 and $11.99 as of June 30, 2021 and December 31, 2020, respectively. The estimated fair value of the equity securities as of December 31, 2020 was calculated based on the following assumptions: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, ​ December 31, ​ ​ ​ 2021 ​ 2020 Closing common stock price ​ $ 14.27 ​ $ 11.99 ​ ​ ​ ​ ​ ​ ​ ​ ​ Tranche 1: ​ ​ ​ ​ ​ ​ ​ Discount for lack of marketability ​ N/A (1) % ​ 12 % Estimated time to liquidity of shares ​ ​ ​ ​ 0.25 year ​ ​ ​ ​ ​ ​ ​ ​ ​ Tranche 2: ​ ​ ​ ​ ​ ​ ​ Discount for lack of marketability ​ ​ N/A (1) % ​ 14 % Estimated time to liquidity of shares ​ ​ ​ ​ ​ 0.67 years ​ ​ (1) Due to sufficient and consistent trading volume, the equity investment will be measured at the closing price per the Nasdaq Stock Market as of June 30, 2021. The assumptions related to the unobservable inputs identified above, and any changes in those assumptions thereto, will no longer be considered in determining the fair value of the equity securities. Contingent Consideration The estimated fair value of the contingent consideration liability at the inception of the Bioasis Royalty Purchase Agreement represents the future consideration that is contingent upon the achievement of specified development milestones for a product candidate. The fair value measurement is based on significant Level 3 inputs such as anticipated timelines and probability of achieving development milestones of each licensed product candidate. Changes in the fair value of the liability for contingent consideration will be recorded in the other income (expense), net line item of the condensed consolidated statements of operations and comprehensive loss until settlement. As of June 30, 2021, there were no changes in the estimated fair value of the contingent consideration from its initial value of $0.1 million. ​

Lease Agreements

Lease Agreements	6 Months Ended
	Jun. 30, 2021
Lease Agreements
Lease Agreements	7. Lease Agreements The Company leases one facility in Emeryville, California under an operating lease that expires in February 2023. The lease contains an option to extend the lease for an additional term, however, the Company is not reasonably certain to exercise this option. The following table summarizes maturity of the Company’s operating lease liabilities as of June 30, 2021 (in thousands): ​ ​ ​ ​ ​ ​ ​ Operating Undiscounted lease payments Leases 2021 (excluding six months ended June 30, 2021) ​ $ 98 2022 ​ 202 2023 ​ 34 Thereafter ​ — Total undiscounted lease payments ​ 334 Present value adjustment ​ (14) Total net lease liabilities $ 320 ​ The following table summarizes the cost components of the Company’s operating leases for the three and six months ended June 30, 2021 and 2020 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, Six Months Ended June 30, ​ 2021 ​ 2020 2021 2020 Lease costs: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating lease cost ​ $ 44 ​ $ 44 $ 88 $ 88 Variable lease cost (1) ​ 2 ​ 1 ​ 5 ​ 2 Total lease costs ​ $ 46 ​ $ 45 $ 93 ​ $ 90 (1) Under the terms of the lease agreements, the Company is also responsible for certain variable lease payments that are not included in the measurement of the lease liability. Variable lease payments include non-lease components such as common area maintenance fees. The following information represents supplemental disclosure for the statement of cash flows related to operating leases (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ Six Months Ended June 30, ​ 2021 ​ 2020 Cash paid for amounts included in the measurement of lease liabilities ​ ​ ​ ​ Operating cash flows under operating leases ​ $ 98 ​ $ 94 ​ The present value assumptions used in calculating the present value of the lease payments as of June 30, 2021 and December 31, 2020 were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, ​ December 31, ​ 2021 ​ 2020 Weighted-average remaining lease term ​ ​ ​ ​ ​ ​ Operating leases ​ 1.67 years ​ ​ 2.17 years ​ Weighted-average discount rate ​ ​ ​ ​ ​ ​ Operating leases ​ 5.51 % ​ 5.51 % ​

Long-Term Debt and Other Financ

Long-Term Debt and Other Financings	6 Months Ended
	Jun. 30, 2021
Long-Term Debt and Other Financings
Long-Term Debt and Other Financings	8. Long-Term Debt and Other Financings Silicon Valley Bank Loan Agreement On May 7, 2018 (the “Effective Date”), the Company executed a Loan and Security Agreement (the “Loan Agreement”) with SVB. Under the Loan Agreement, upon the Company’s request, SVB made advances (each, a “Term Loan Advance”) available to the Company up to $20.0 million (the “Term Loan”). The Company was allowed to borrow advances under the Term Loan from the Effective Date until the earlier of March 31, 2019 or an event of default (the “Draw Period”). The interest rate was calculated at a rate equal to the greater of (i) 4.75%, or (ii) 0.25% plus the prime rate as reported from time to time in The Wall Street Journal. Payments under the Loan Agreement were interest only until the first anniversary of the funding date of each Term Loan Advance. The interest-only period was followed by equal monthly payments of principal and interest over 24 months. Each Term Loan Advance was scheduled to 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. The entire principal balance, including a final payment fee equal to 8.5% of the original principal, was due and payable on the Loan Maturity Date. In June 2021, the Company repaid its principal balance of $6.5 million and paid the 8.5% final payment fee of $1.4 million to SVB. The Company also paid SVB a prepayment fee of 1% of the outstanding principal balance. In connection with the Loan Agreement, the Company issued a warrant to SVB which is exercisable in whole or in part for up to an aggregate of 6,332 shares of common stock with an exercise price of $23.69 per share (the “Warrant”). The Warrant may be exercised on a cashless basis and is exercisable within 10 years from the date of issuance or upon the consummation of certain acquisitions of the Company. The fair value of the Warrant issued to SVB was determined using the Black-Scholes Model and was estimated to be $0.1 million. In addition, the Company incurred debt issuance costs of $0.2 million in connection with the Loan Agreement. On March 4, 2019, the Loan Agreement was amended to extend the Draw Period from March 31, 2019 to March 31, 2020. In connection with the amendment, the Company issued a second warrant to SVB which is exercisable in whole or in part for up to an aggregate of 4,845 shares of common stock with an exercise price of $14.71 per share. The fair value of the second warrant issued to SVB was determined using the Black-Scholes Model and was estimated to be $0.1 million. The Draw Period has not been extended further. As of June 30, 2021, both warrants are outstanding. In addition, both warrants may be exercised on a cashless basis and are exercisable within 10 years from the date of issuance or upon the consummation of certain acquisitions of the Company. In September 2018, the Company borrowed advances of $7.5 million under the Loan Agreement in connection with the Agenus Royalty Purchase Agreement (Note 5). The Company recorded a discount of $0.3 million against the debt, which was being amortized to interest expense over the term of the Term Loan Advance using the effective interest method. During the year ended December 31, 2019, the Company borrowed advances totaling $9.5 million under the Loan Agreement in connection with the Aronora Royalty Purchase Agreement, Palo Royalty Purchase Agreement and payment of the Aronora Contingent Consideration (Note 5). The Company recorded a discount of $45,000 against the debt, which was being amortized to interest expense over the term of the Term Loan Advance using the effective interest method. The Company recorded $0.1 million and $0.2 million of non-cash interest expense resulting from the amortization of the discount and accretion of the final payment for the three and six months ended June 30, 2021, respectively. The Company recorded $0.2 million and $0.4 million of non-cash interest expense resulting from the amortization of the discount and accretion of the final payment for the three and six months ended June 30, 2020, respectively. As of December 31, 2020, the carrying value of the debt under the Loan Agreement was $11.8 million. Of this amount, $8.1 million was classified as current portion of long-term debt and $3.7 million was classified as long-term debt on the condensed consolidated balance sheet. In June 2021, the Company paid off its entire outstanding principal balance to SVB. Upon repayment of the principal balance, the Company recognized a loss on extinguishment of $0.3 million in the other income (expense), net line item of the condensed consolidated statement of operations for the three and six months ended June 30, 2021. As of June 30, 2021, there was no carrying value of the debt under the Loan Agreement. Novartis Note In May 2005, the Company executed a secured note agreement (the “Note Agreement”) with Novartis, which was due and payable in full in June 2015. Under the Note Agreement, the Company borrowed semi-annually to fund up to 75% of the Company’s research and development and commercialization costs under its collaboration arrangement with Novartis, not to exceed $50.0 million in aggregate principal amount. Interest on the principal amount of the loan accrued at six-month LIBOR plus 2% and the interest rate reset in June and December annually. Accrued interest was payable semi-annually in June and December of each year or, at the Company’s election, the semi-annual interest payments could be added to the outstanding principal amount, in lieu of a cash payment, as long as the aggregate principal amount did not exceed $50.0 million. The Company made this election for all interest payments. Loans under the Note Agreement were secured by the Company’s interest in its collaboration with Novartis, including any payments owed to it thereunder. In June 2021, the Company repaid its outstanding principal balance to Novartis of $9.1 million and extinguished its debt obligation. On September 30, 2015, concurrent with the execution of a license agreement with Novartis International as discussed in Note 4, XOMA and NIBR, who assumed the rights to the note from Novartis Vaccines Diagnostics, Inc. executed an amendment to the Note Agreement (the “Secured Note Amendment”) under which the parties extended the maturity date of the note from September 30, 2015 to September 30, 2020, and eliminated the mandatory prepayment previously required to be made with certain proceeds of pre-tax profits and royalties. In addition, upon achievement of a specified development and regulatory milestone, the then-outstanding principal amount of the note was to be reduced by $7.3 million rather than the Company receiving such amount as a cash payment. On September 22, 2017, in connection with the Gevokizumab License Agreement with Novartis, the Company and NIBR executed an amendment to the Secured Note Amendment under which the parties further extended the maturity date of the Secured Note Amendment from September 30, 2020 to September 30, 2022. On October 21, 2020, the first patient was dosed in Novartis International’s NIS793 Phase 2 clinical trial and the Company earned a $25.0 million milestone pursuant to the Anti-TGFβ Antibody License Agreement, of which $17.7 million was received in cash and $7.3 million was recognized as a reduction to the debt obligation to Novartis. As of December 31, 2020, the outstanding principal balance under the Secured Note Amendment was $9.1 million and was included in long-term debt in the accompanying condensed consolidated balance sheet. In June 2021, the Company repaid its entire outstanding debt balance to Novartis. The repayment of principal did not result in any gain or loss on extinguishment. As of June 30, 2021, there was no carrying value of the debt under the Secured Note Agreement. Interest Expense Amortization of debt issuance costs and discounts are included in interest expense. Interest expense in the condensed consolidated statements of operations and comprehensive loss relates to the following debt instruments (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ Six Months Ended ​ ​ ​ June 30, ​ ​ June 30, ​ ​ 2021 2020 2021 2020 SVB loan ​ $ 135 ​ $ 356 ​ ​ $ 373 ​ $ 739 ​ Novartis note ​ 37 ​ 151 ​ 88 ​ 309 Other ​ — ​ 1 ​ — ​ 2 Total interest expense ​ $ 172 ​ $ 508 ​ ​ $ 461 ​ $ 1,050 ​ ​ ​

Common Stock Warrants

Common Stock Warrants	6 Months Ended
	Jun. 30, 2021
Common Stock Warrants
Common Stock Warrants	9. Common Stock Warrants As of June 30, 2021 and December 31, 2020, the following common stock warrants were outstanding: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Exercise Price June 30, December 31, Issuance Date ​ Expiration Date ​ Balance Sheet Classification ​ per Share ​ 2021 ​ 2020 February 2016 February 2021 Stockholders’ equity ​ $ 15.40 — 8,249 May 2018 May 2028 Stockholders’ equity ​ $ 23.69 6,332 6,332 March 2019 ​ March 2029 ​ Stockholders’ equity ​ $ 14.71 ​ 4,845 ​ 4,845 ​ ​ 11,177 19,426 ​ During the first quarter of 2021, the Company issued 4,917 shares of common stock through a cashless exercise of the February 2016 common stock warrants held by Torreya Partners LLC.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2021
Commitments and Contingencies
Commitments and Contingencies	10. Commitments and Contingencies Collaborative Agreements, Royalties and Milestone Payments The Company has committed to make potential future milestone payments and legal fees to third parties as part of licensing and development programs. Payments under these agreements become due and payable only upon the achievement of certain developmental, regulatory and commercial milestones by the Company’s licensees. Because it is uncertain if and when these milestones will be achieved, such contingencies, aggregating up to $7.6 million (assuming one product per contract meets all milestones events) have not been recorded on the accompanying condensed consolidated balance sheets. The Company is unable to determine precisely when and if payment obligations under the agreements will become due as these obligations are based on milestone events, the achievement of which is subject to a significant number of risks and uncertainties. Contingent Consideration Pursuant to the Company’s royalty purchase agreement with Bioasis the Company has committed to pay the Bioasis Contingent Consideration and the Aronora Royalty Milestones. The Company recorded $0.1 million for the Bioasis Contingent Consideration which represents the estimated fair value of these potential future payments at the inception of the agreements. The contingent consideration is remeasured at fair value at each reporting period, with changes in fair value recorded in other income (expense), net. As of June 30, 2021, there were no changes in the estimated fair value of the Bioasis Contingent Consideration from its initial value. The liability for future Aronora Royalty Milestones will be recorded when the amounts by product are estimable and probable. As of June 30, 2021, none of these Aronora Royalty Milestones were assessed to be probable and as such, no liability was recorded on the condensed consolidated balance sheet. ​

Stock-based Compensation

Stock-based Compensation	6 Months Ended
	Jun. 30, 2021
Stock-based Compensation
Compensation and Other Benefit Plans	11. Stock-based Compensation The Company may grant qualified and non-qualified stock options, common stock and other stock-based awards under various plans to directors, officers, employees and other individuals. Stock options are granted at exercise prices of not less than the fair market value of the Company’s common stock on the date of grant. Additionally, the Company has an Employee Stock Purchase Plan (“ESPP”) that allows employees to purchase Company shares at a purchase price equal to 85% of the lower of the fair market value of the Company’s common stock on the first trading day of the offering period or on the last day of the offering period. Stock Options Stock options generally vest monthly over three years for employees and one year for directors. Stock options held by employees who qualify for retirement age (defined as employees that are a minimum of 55 years of age and the sum of their age plus years of full-time employment with the Company exceeds 70 years) vest on the earlier of scheduled vest date or the date of retirement. The fair value of the stock options granted during the three and six months ended June 30, 2021 and 2020, was estimated based on the following weighted average assumptions: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, ​ Six Months Ended June 30, ​ 2021 2020 2021 2020 Dividend yield 0 % 0 % 0 % 0 % Expected volatility 76 % 100 % 94 % 100 % Risk-free interest rate 1.06 % 0.40 % 0.77 % 0.77 % Expected term 6.00 years ​ 5.93 years ​ 5.68 years ​ 5.66 years ​ ​ Stock option activity for the six months ended June 30, 2021, was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted Weighted ​ ​ ​ ​ ​ Average ​ Average ​ Aggregate ​ ​ ​ ​ Exercise ​ Contractual ​ Intrinsic ​ ​ Number of ​ Price ​ Term ​ Value ​ ​ shares ​ Per Share ​ (in years) ​ (in thousands) Outstanding at January 1, 2021 ​ ​ 1,827,906 ​ $ 20.66 ​ 6.31 $ 51,401 Granted ​ 176,429 ​ 37.62 ​ ​ Exercised ​ (73,575) ​ 13.35 ​ ​ Forfeited, expired or cancelled ​ ​ (57,115) ​ 71.26 ​ ​ Outstanding at June 30, 2021 ​ ​ 1,873,645 ​ $ 21.00 ​ 6.19 ​ $ 33,125 Exercisable at June 30, 2021 ​ ​ 1,535,686 ​ $ 19.37 ​ 5.58 ​ $ 30,459 ​ The aggregate intrinsic value of stock options exercised during the six months ended June 30, 2021 and 2020 was $1.5 million and $40,000, respectively. The weighted-average grant-date fair value per share of the options granted during the six months ended June 30, 2021 and 2020 was $27.89 and $16.22, respectively. As of June 30, 2021, $4.3 million of total unrecognized compensation expense related to stock options is expected to be recognized over a weighted average period of 1.73 years. Stock-based Compensation Expense The following table shows total stock-based compensation expense for stock options and ESPP in the condensed consolidated statements of operations and comprehensive loss (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, ​ Six Months Ended June 30, ​ 2021 2020 2021 2020 Research and development ​ $ — ​ $ — ​ $ — ​ $ — General and administrative ​ 768 ​ 773 ​ 3,666 ​ 2,561 Total stock-based compensation expense ​ $ 768 ​ $ 773 ​ $ 3,666 ​ $ 2,561 ​

Capital Stock

Capital Stock	6 Months Ended
	Jun. 30, 2021
Capital Stock
Capital Stock	12. Capital Stock Series X and Series Y Convertible Preferred Stock The Company sold directly to Biotechnology Value Fund, L.P. (“BVF”) 5,003 shares of Series X convertible preferred stock in 2017 and 1,252.772 shares of Series Y preferred stock in 2018. There were 5,003 shares of Series X convertible preferred stock and no shares of Series Y convertible preferred stock outstanding as of June 30, 2021, after BVF converted all Series Y preferred stock into common stock on April 15, 2020. The Series X and Series Y convertible preferred stock have the following characteristics, which are set forth in Certificates of Designation of Preferences, Rights and Limitations filed with the Delaware Secretary of State. Dividends— Liquidation Rights— Conversion— Voting Rights— Classification— Beneficial Conversion Feature— the stock first became convertible. There was no beneficial conversion feature associated with the issuance of Series Y convertible preferred stock. Series A Preferred Stock On December 15, 2020, the Company sold 984,000 shares of its 8.625% Series A cumulative, perpetual preferred stock at the price of $25.00 per share, through a public offering for aggregate gross proceeds of $24.6 million. Total offering costs of $2.0 million were offset against the proceeds from the sale of Series A Preferred Stock, for total net proceeds of $22.6 million. Mr. Matthew Perry, a member of the Company’s Board of Directors and President of BVF, purchased 200,000 shares of Series A Preferred Stock in the public offering at the public offering price of $25.00 per share for an aggregate amount of $5.0 million. The spouse of James Neal, the Company’s Chief Executive Officer and a director, purchased 8,000 shares of the Series A Preferred Stock in the public offering at the public offering price of $25.00 per share for an aggregate amount of $0.2 million. ​ The Series A Preferred Stock has the following characteristics, which are set forth in the Certificate of Designation of Preferences, Rights and Limitations filed with the Delaware Secretary of State. Dividends— Liquidation Rights Redemption and Special Optional Redemption Conversion— Voting Rights— Classification— Depositary Shares Representing Interest in Series B Preferred Stock On April 9, 2021, the Company sold 1,600,000 depositary shares, each representing a 1/1000th ​ The spouse of James Neal, the Chief Executive Officer and a director, purchased 8,000 shares of the depositary shares in the public offering at the public offering price of $25.00 per share for an aggregate amount of $0.2 million. ​ The Series B Preferred Stock has the following characteristics, which are set forth in the Certificate of Designation of 8.375% Series B Cumulative Perpetual Preferred Stock, as corrected, filed with the Delaware Secretary of State. ​ Dividends— . ​ Liquidation Preference ​ Redemption and Special Redemption - On and after April 15, 2022, the Company, at its option, may redeem the Series B Preferred Stock, for cash, in whole or in part, at any time or from time to time, as follows: (i) between April 15, 2022 to April 15, 2023, at a redemption price of $26,000.00 per share ( $26.00 per depositary share), (ii) between April 15, 2023 to April 15, 2024, at a redemption price of $25,750.00 per share ( $25.75 per depositary share), (iii) between April 15, 2024 to April 15, 2025, at a redemption price of $25,500.00 per share ( $25.50 per depositary share), (iv) between April 15, 2025 to April 15, 2026, at a redemption price of $25,250.00 per share ( $25.25 per depositary share), and (v) after April 15, 2026, at a redemption price of $25,000.00 per share ( $25.00 per depositary share), and in each case, plus any accrued and unpaid dividends thereon up to but not including the date fixed for redemption, without interest. If fewer than all of the outstanding shares of Series B Preferred Stock are to be redeemed, the shares to be redeemed will be determined pro rata or by lot. Upon the occurrence of a delisting event or change of control the Company will have the option to redeem the Series B Preferred Stock, in whole or in part, for cash at $25,000.00 per share plus accrued and unpaid dividends. ​ Conversion - consideration) per share of Series B Preferred Stock, equal to the lesser of (A) the quotient obtained by dividing (1) the sum of the $25,000.00 per share liquidation preference plus the amount of any accumulated and unpaid dividends up to, but not including, the delisting event conversion date or change of control conversion date, as applicable (unless the delisting event conversion date or change of control conversion date, is after a record date for a Series B Preferred Stock dividend payment and prior to the corresponding Series B Preferred Stock dividend payment date, in which case no additional amount for such accumulated and then remaining unpaid dividend will be included in this sum) by (2) the common stock price (such quotient, the “Conversion Rate”); and (B) 1,253.13 (1.25313 per depositary share) (i.e., the “Share Cap”), subject to certain adjustments described in the Series B Preferred Stock Certificate of Designation. Voting Rights Classification Dividends On March 17, 2021, the Company’s Board of Directors declared a cash dividend of $0.71875 per share payable to holders of Series A Preferred Stock, which the Company paid on April 15, 2021 BVF Ownership In February 2020, BVF elected to increase the beneficial ownership limitation of the Series Y preferred stock to 50%, which became effective on April 11, 2020. On April 15, 2020, BVF converted all of its shares of Series Y preferred stock into common stock. As of June 30, 2021, BVF owned approximately 31.2% of the Company’s total outstanding shares of common stock, and if all the Series X convertible preferred shares were converted, BVF would own 52.3% of the Company’s total outstanding shares of common stock. The Company’s Series A Preferred Stock becomes convertible upon the occurrence of specific events and as of June 30, 2021, the contingency was not met, therefore the Series A Preferred Stock is not included in the as-converted ownership calculation. Due to its significant equity ownership, BVF is considered a related party of the Company. 2018 ATM Agreement On December 18, 2018, the Company entered into an At The Market Issuance Sales Agreement (the “2018 ATM Agreement”) with H.C. Wainwright & Co., LLC (“HCW”), under which the Company may offer and sell from time to time at its sole discretion shares of its common stock through HCW as its sales agent, in an aggregate amount not to exceed $30.0 million. HCW may sell the shares by any method permitted by law deemed to be an “at the market” offering as defined in Rule 415 of the Securities Act, and will use its commercially reasonable efforts consistent with its normal trading and sales practices to sell the shares up to the amount specified. The Company will pay HCW a commission of up to 3% of the gross proceeds of any shares of common stock sold under the 2018 ATM Agreement. On March 10, 2021, the Company amended the 2018 ATM Agreement with HCW to increase the aggregate amount of shares of its common stock that it could sell through HCW as its sales agent to $50.0 million. No shares have been sold under the 2018 ATM Agreement since the agreement was executed.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2021
Income Taxes
Income Taxes	13. Income Taxes The Company recorded an income tax benefit of $1.5 million for the six months ended June 30, 2020, as a result of the Coronavirus Aid, Relief, and Economic Security Act and no income tax provision for the six months ended June 30, 2021. The Company continues to maintain a full valuation allowance against its remaining net deferred tax assets. During the three and six months ended June 30, 2021 the Company received $1.5 million in cash for its income tax receivable. The Company has a total of $5.9 million of gross unrecognized tax benefits, none of which would affect the effective tax rate upon realization as it currently has a full valuation allowance against its U.S. net deferred tax assets. The reversal of related deferred tax assets will be offset by a valuation allowance, should any of these uncertain tax positions be favorably settled in the future. The Company does not expect its unrecognized tax benefits to change significantly over the next twelve months. The Company will recognize interest and penalties accrued on any unrecognized tax benefits as a component of income tax expense. Through June 30, 2021, the Company has not accrued interest or penalties related to uncertain tax positions.

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2021
Subsequent Events
Subsequent Events	14. Subsequent Events Royalty Purchase Agreement with Kuros On July 14, 2021, the Company entered into a royalty purchase agreement (the “Kuros Royalty Purchase Agreement”) with Kuros Biosciences AG, Kuros US LLC and Kuros Royalty Fund (US) LLC (collectively “Kuros”). Pursuant to the Kuros Royalty Purchase Agreement, XOMA acquired the rights to 100% of the potential future royalties from commercial sales, which are tiered from high-single to low double digits, and up to $25.0 million in pre-commercial milestone payments associated with an existing license agreement related to Checkmate Pharmaceuticals’ vidutolimod (CMP-001), a Toll-like receptor 9 agonist, packaged in a virus-like particle, for an upfront payment of $7.0 million plus potential future sales milestone payments based on net sales of vidutolimod.

Basis of Presentation and Sig_2

Basis of Presentation and Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2021
Basis of Presentation and Significant Accounting Policies
Basis of Presentation	Basis of Presentation The condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany accounts and transactions among consolidated entities were eliminated upon consolidation. The unaudited condensed consolidated financial statements were prepared in accordance with generally accepted accounting principles (“GAAP”) in the United States for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. As permitted under those rules certain footnotes or other financial information can be condensed or omitted. These financial statements and related disclosures have been prepared with the assumption that users of the interim financial information have read or have access to the audited consolidated financial statements for the preceding fiscal year. Accordingly, these statements should be read in conjunction with the audited consolidated financial statements and related notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020, filed with the U.S. Securities and Exchange Commission (“SEC”) on March 10, 2021. These financial statements have been prepared on the same basis as the Company’s annual consolidated financial statements and, in the opinion of management, reflect all adjustments, consisting only of normal recurring adjustments that are necessary for a fair statement of the Company’s consolidated financial information. The interim results of operations are not necessarily indicative of the results that may be expected for the full year.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP in the United States requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenue and expenses, and related disclosures. On an ongoing basis, management evaluates its estimates including, but not limited to, those related to revenue recognition, revenue recognized under units-of-revenue method, equity securities, legal contingencies and stock-based compensation. The Company bases its estimates on historical experience and on various other market-specific and other relevant assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ significantly from these estimates, such as the Company’s billing under government contracts and amortization of the payments received from HealthCare Royalty Partners II, L.P. (“HCRP”). Under the Company’s contracts with the National Institute of Allergy and Infectious Diseases (“NIAID”), a part of the National Institutes of Health (“NIH”), the Company billed using NIH’s provisional rates and thus is subject to future audits at the discretion of NIAID’s contracting office. In October of 2019, NIH notified the Company that it engaged KPMG to perform an audit of the Company’s incurred cost submissions for 2013, 2014 and 2015. The audit procedures were completed and the Company adjusted its estimated liability owed to NIH to $1.4 million as of December 31, 2020 (Note 4). The estimated liability owed to NIH had not changed as of June 30, 2021. The audit remains subject to further review by NIH as part of the contract close-out process, which includes finalization of rates for years 2010 through 2015, and the Company may incur further liability as a result. In addition, under the contracts with HCRP, the amortization for the reporting period is calculated based on the payments expected to be made by the licensees to HCRP over the term of the arrangement. Any changes to the estimated payments by the licensees to HCRP can result in a material adjustment to revenue previously reported. The COVID-19 pandemic has resulted in a global slowdown of economic activity which has led to delays and could result in further delays or terminations of some clinical trials underlying the Company’s royalty purchase agreements. Estimates and assumptions about future events and their effects cannot be determined with certainty and therefore require the exercise of judgment. These estimates may change, as new events occur and additional information is obtained, and are recognized in the condensed consolidated financial statements as soon as they become known. Actual results could differ from those estimates and any such differences may be material to the Company’s financial statements.
Cash and Restricted Cash	Cash and Restricted Cash Cash consists of bank deposits held in business checking and interest-bearing deposit accounts. As of June 30, 2021, the Company did not have any cash equivalent balances, defined as highly liquid financial instruments purchased with original maturities of three months or less. Restricted cash consists of bank deposits held to pay dividends on the Company’s Series A Preferred Stock and Series B Preferred Stock. The Company maintains cash and restricted cash balances at commercial banks. Balances commonly exceed the amount insured by the Federal Deposit Insurance Corporation. The Company has not experienced any losses in such accounts, and management believes that the Company is not exposed to any significant credit risk with respect to such cash and restricted cash. ​ The following table provides a reconciliation of cash and restricted cash reported within the consolidated balance sheets that sum to the total of the same amounts shown in the consolidated statements of cash flows (in thousands): ​ ​ ​ ​ ​ ​ ​ Six Months Ended June 30, ​ 2021 ​ 2020 ​ ​ ​ ​ ​ ​ Cash $ 78,945 ​ $ 49,491 Restricted cash ​ 4,840 ​ ​ — Total cash and restricted cash $ 83,785 ​ $ 49,491
Revenue Recognition	Revenue Recognition The Company recognizes revenue from all contracts with customers according to Accounting Standards Codification (“ASC”) Topic 606, Revenue from Contracts with Customers To determine revenue recognition for arrangements that the Company determines are within the scope of ASC 606, the Company performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the Company satisfies a performance obligation. The Company only applies the five-step model to contracts when it is probable that the Company will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. At contract inception, once the contract is determined to be within the scope of ASC 606, the Company assesses the goods or services promised within each contract and determines those that are performance obligations, and assesses whether each promised good or service is distinct. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation based on relative fair values, when (or as) the performance obligation is satisfied. The Company recognizes revenue from its license and collaboration arrangements and royalties. The terms of the arrangements generally include payment to the Company of one or more of the following: non-refundable, upfront license fees, development, regulatory and commercial milestone payments, and royalties on net sales of licensed products. License of intellectual property If the license to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenue from non-refundable, upfront fees allocated to the license when the license is transferred to the customer and the customer is able to use and benefit from the license. For licenses that are bundled with other promises, such as transfer of related materials, process and know-how, the Company utilizes judgement to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time. Under the Company’s license agreements, the nature of the combined performance obligation is the granting of licenses to the customers as the other promises are not separately identifiable in the context of the arrangement. Since the Company grants the license to a customer as it exists at the point of transfer, and is not involved in any future development or commercialization of the products related to the license, the nature of the license is a right to use the Company’s intellectual property as transferred. As such, the Company recognizes revenue related to the combined performance obligation upon completion of the delivery of the related materials, process and know-how (i.e., at a point in time). Milestone payments At the inception of each arrangement that includes development and regulatory milestone payments, the Company evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price. ASC 606 suggests two alternatives to use when estimating the amount of variable consideration: the expected value method and the most likely amount method. Under the expected value method, an entity considers the sum of probability-weighted amounts in a range of possible consideration amounts. Under the most likely amount method, an entity considers the single most likely amount in a range of possible consideration amounts. The Company uses the most likely amount method for development and regulatory milestone payments. If it is probable that a significant cumulative revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the control of the Company or the licensee, such as regulatory approvals, are not considered probable of being achieved until those approvals are received. The transaction price is then allocated to each performance obligation on a relative stand-alone selling price basis. The Company recognizes revenue as or when the performance obligations under the contract are satisfied. At the end of each subsequent reporting period, the Company re-evaluates the probability or achievement of each such milestone and any related constraint, and if necessary, adjusts its estimates of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect revenue and earnings in the period of adjustment. Royalties For arrangements that include sales-based royalties, including milestone payments based on the level of sales, and the license is deemed to be the predominant item to which the royalties relate, the Company recognizes revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). Upfront payments and fees are recorded as deferred revenue upon receipt or when due and may require deferral of revenue recognition to a future period until the Company performs its obligations under these arrangements. Amounts payable to the Company are recorded as accounts receivable when the Company’s right to consideration is unconditional. The Company does not assess whether a contract has a significant financing component if the expectation at contract inception is such that the period between payment by the customer and the transfer of the promised goods or services to the customer will be one year or less.
Sale of Future Revenue Streams	Sale of Future Revenue Streams The Company has sold its rights to receive certain milestones and royalties on product sales. In the circumstance where the Company has sold its rights to future milestones and royalties under a license agreement and also maintains limited continuing involvement in the arrangement (but not significant continuing involvement in the generation of the cash flows that are due to the purchaser), the Company defers recognition of the proceeds it receives for the sale of milestone or royalty streams and recognizes such unearned revenue as revenue under units-of-revenue method over the life of the underlying license agreement. Under the units-of-revenue method, amortization for a reporting period is calculated by computing a ratio of the proceeds received from the purchaser to the total payments expected to be made to the purchaser over the term of the agreement, and then applying that ratio to the period’s cash payment. Estimating the total payments expected to be received by the purchaser over the term of such arrangements requires management to use subjective estimates and assumptions. Changes to the Company’s estimate of the payments expected to be made to the purchaser over the term of such arrangements could have a material effect on the amount of revenues recognized in any particular period.
Stock-Based Compensation	Stock-Based Compensation The Company recognizes compensation expense for all stock-based payment awards made to the Company’s employees, consultants and directors that are expected to vest based on estimated fair values. The valuation of stock option awards is determined at the date of grant using the Black-Scholes Option Pricing Model (the “Black-Scholes Model”). The Black-Scholes Model requires inputs such as the expected term of the option, expected volatility and risk-free interest rate. To establish an estimate of expected term, the Company considers the vesting period and contractual period of the award and its historical experience of stock option exercises, post-vesting cancellations and volatility. The estimate of expected volatility is based on the Company’s historical volatility. The risk-free rate is based on the yield available on United States Treasury zero-coupon issues corresponding to the expected term of the award. The Company records forfeitures when they occur. The Company records compensation expense for service-based awards on a straight-line basis over the requisite service period, which is generally the vesting period of the award, or to the date on which retirement eligibility is achieved, if shorter.
Equity Securities	Equity Securities The Company received shares of common stock from Rezolute, Inc. (“Rezolute”) (Note 4). Equity investments in Rezolute are classified in the condensed consolidated balance sheets as equity securities. The equity securities are measured at fair value, with changes in fair value recorded in the other income (expense), net line item of the condensed consolidated statement of operations and comprehensive loss at each reporting period. The Company remeasures its equity investments at each reporting period until such time that the investment is sold or disposed of. If the Company sells an investment, any realized gains and losses on the sale of the securities will be recognized in the condensed consolidated statement of operations and comprehensive loss in the period of sale. In October 2020, Rezolute completed a 1:50
Purchase of Rights to Future Milestones and Royalties	Purchase of Rights to Future Milestones and Royalties The Company has purchased rights to receive a portion of certain future developmental, regulatory and commercial sales milestones, royalties and option fees on sales of products currently in clinical development. The Company acquired such rights from various entities and recorded the amount paid for these rights as long-term royalty receivables (Note 5). In addition, the Company may be obligated to make contingent payments related to certain product development milestones, fees upon exercise of options related to future license products and sales-based milestones. The contingent payments are evaluated whether they are freestanding instruments or embedded derivatives. If freestanding instruments, the contingent payments are measured at fair value at the inception of the arrangement, subject to remeasurement to fair value each reporting period. Any changes in the estimated fair value is recorded in the condensed consolidated statement of operations and comprehensive loss. The Company accounts for milestone and royalty rights related to developmental pipeline products on a non-accrual basis using the cost recovery method. These developmental pipeline products are non-commercialized, non-approved products that require Food and Drug Administration (“FDA”) or other regulatory approval, and thus have uncertain cash flows. The Company is not yet able to reliably forecast future cash flows given their pre-commercial stages of development. The related receivable balance is classified as noncurrent since no payments are probable to be received in the near term. Under the cost recovery method, any milestone or royalty payment received is recorded as a direct reduction of the recorded receivable balance. When the recorded receivable balance has been fully collected, any additional amounts collected are recognized as revenue. The Company reviews public information on clinical trials, press releases and updates from its partners regularly to identify any impairment indicators or changes in expected recoverability of the long-term royalty receivable asset. If an impairment indicator is identified, and the Company determines expected future cash flows discounted to the current period are less than the carrying value of the asset, the Company will record impairment. The impairment will be recognized by reducing the financial asset to an amount that represents the present value of the most recent estimate of future cash flows. No impairment indicators were identified, and no impairment was recorded as of June 30, 2021 and December 31, 2020.
Leases	Leases The Company leases its headquarters office space in Emeryville, California. The Company determines the initial classification and measurement of its right-of-use assets and lease liabilities at the lease commencement date and thereafter if modified. The lease term includes any renewal options and termination options that the Company is reasonably certain to exercise. The present value of lease payments is determined by using the interest rate implicit in the lease, if that rate is readily determinable; otherwise, the Company uses its incremental borrowing rate. The incremental borrowing rate is determined by using the rate of interest that the Company would pay to borrow on a collateralized basis an amount equal to the lease payments for a similar term and in a similar economic environment. The Company built its incremental borrowing rate starting with the interest rate on its fully collateralized debt and then adjusted it for lease term length. Rent expense for operating leases is recognized on a straight-line basis, unless the right-of-use asset has been impaired, over the reasonably assured lease term based on the total lease payments and is included in operating expenses in the condensed consolidated statements of operations and comprehensive loss. If an operating lease were to reflect impairment, the Company will recognize the amortization of the right-of-use asset on a straight-line basis over the remaining lease term with rent expense still included in operating expenses in the condensed consolidated statements of operations and comprehensive loss. For all leases, rent payments that are based on a fixed index or rate at the lease commencement date are included in the measurement of lease assets and lease liabilities at the lease commencement date. The Company has elected the practical expedient to not separate lease and non-lease components. The Company’s non-lease components are primarily related to property maintenance, which varies based on future outcomes, and thus is recognized in rent expense when incurred.
Income Taxes	Income Taxes The Company accounts for income taxes using the liability method under which deferred tax assets and liabilities are determined based on differences between financial reporting and tax bases of assets and liabilities and are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse. Valuation allowances are established when necessary to reduce deferred tax assets to the amount which is more likely than not to be realizable. The recognition, derecognition and measurement of a tax position is based on management’s best judgment given the facts, circumstances and information available at each reporting date. The Company’s policy is to recognize interest and penalties related to the underpayment of income taxes as a component of income tax expense. To date, there have been no interest or penalties charged in relation to the unrecognized tax benefits.
Net Loss per Share Attributable to Common Stockholders	Net Loss per Share Attributable to Common Stockholders The Company calculates basic and diluted loss per share attributable to common stockholders using the two-class method. The Company’s convertible Series X and Series Y preferred stocks participate in any dividends declared by the Company on its common stock and are therefore considered to be participating securities. The Company’s Series A and Series B Preferred Stock do not participate in any dividends or distribution by the Company on its common stock and are therefore not considered to be participating securities. Under the two-class method, net income, as adjusted for any accumulated dividends on Series A and Series B Preferred Stock for the period and any deemed dividends related to beneficial conversion features on convertible preferred stock, if applicable, is allocated to each class of common stock and participating security as if all of the net income for the period had been distributed. Undistributed earnings allocated to participating securities are subtracted from net income in determining net income attributable to common stockholders. During periods of loss, the Company allocates no loss to participating securities because they have no contractual obligation to share in the losses of the Company. Basic net loss per share attributable to common stockholders is then calculated by dividing the net loss attributable to common stockholders by the weighted average number of shares of common stock outstanding during the period. All participating securities are excluded from the basic weighted average common shares outstanding. Diluted net loss per share attributable to common stockholders is based on the weighted average number of shares outstanding during the period, adjusted to include the assumed exercise of certain stock options and warrants for common stock. The calculation of diluted net loss per share attributable to common stockholders requires that, to the extent the average market price of the underlying shares for the reporting period exceeds the exercise price of any outstanding options or warrants, the presumed exercise of such securities are dilutive to net loss per share attributable to common stockholders for the period. Adjustments to the denominator are required to reflect the related dilutive shares. The Company’s Series A and Series B Preferred Stock become convertible upon the occurrence of specific events other than a change in the Company’s share price and therefore, are not included in the diluted shares until the contingency is resolved.
Concentration of Risk	Concentration of Risk Cash and receivables are financial instruments which potentially subject the Company to concentrations of credit risk, as well as liquidity risk. The Company monitors the creditworthiness of its customers to which it grants credit terms in the normal course of business but does not generally require collateral on receivables. For the three months ended June 30, 2021, two partners represented 55% and 42% of total revenues. For the six months ended June 30, 2021, two partners represented 57% and 39% of total revenues. For the three months ended June 30, 2020, one partner represented 88% of total revenues. For the six months ended June 30, 2020, two partners represented 56% and 40% of total revenues. As of December 31, 2020, one partner represented 100% of the trade receivables, net balance. As of June 30, 2021, the Company had no trade receivables, net balance.
Comprehensive Loss	Comprehensive Loss Comprehensive loss is comprised of two components: net loss and other comprehensive (loss) income. Other comprehensive (loss) income refers to gains and losses that under U.S. GAAP are recorded as an element of stockholders’ equity but are excluded from net loss. The Company did not record any transactions within other comprehensive (loss) income in the periods presented and, therefore, the net loss and comprehensive loss were the same for all periods presented.
Accounting Pronouncements Recently Adopted and Recent Accounting Pronouncements	Accounting Pronouncements Recently Adopted In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. In August 2020, the FASB issued ASU 2020-06, Debt – Debt with Conversion and Other Options (Subtopic 470-20) and Derivative and Hedging – Contracts in Entity’s Own Equity (Subtopic 815-40). In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting Recent Accounting Pronouncements In June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments In May 2021, the FASB issued ASU 2021-04, Earnings Per Share (Topic 260), Debt—Modifications and Extinguishments (Subtopic 470-50), Compensation—Stock Compensation (Topic 718), and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40): Issuer’s Accounting for Certain Modifications or Exchanges of Freestanding Equity-Classified Written Call Options

Basis of Presentation and Sig_3

Basis of Presentation and Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2021
Basis of Presentation and Significant Accounting Policies
Schedule of cash and restricted cash	The following table provides a reconciliation of cash and restricted cash reported within the consolidated balance sheets that sum to the total of the same amounts shown in the consolidated statements of cash flows (in thousands): ​ ​ ​ ​ ​ ​ ​ Six Months Ended June 30, ​ 2021 ​ 2020 ​ ​ ​ ​ ​ ​ Cash $ 78,945 ​ $ 49,491 Restricted cash ​ 4,840 ​ ​ — Total cash and restricted cash $ 83,785 ​ $ 49,491

Condensed Consolidated Financ_2

Condensed Consolidated Financial Statements Detail (Tables)	6 Months Ended
	Jun. 30, 2021
Condensed Consolidated Financial Statements Detail [Abstract]
Accrued and Other Liabilities	Accrued and other liabilities consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, ​ December 31, ​ 2021 2020 Accrued legal and accounting fees ​ $ 454 ​ $ 351 Accrued incentive compensation ​ ​ 466 ​ ​ 71 Accrued payroll and other ​ 139 ​ 220 Total ​ $ 1,059 ​ $ 642 ​
Reconciliation of Numerator and Denominator Used in Calculation of Basic and Diluted Net (Loss) per Share Available to Common Stockholders	The following is a reconciliation of the numerator (net loss) and the denominator (number of shares) used in the calculation of basic and diluted net loss per share attributable to common stockholders (in thousands, except per share amounts): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, ​ Six Months Ended June 30, ​ 2021 2020 2021 2020 Numerator ​ ​ ​ ​ Net loss ​ $ (2,237) ​ $ (3,533) ​ $ (9,610) ​ $ (8,291) Less: Series A accumulated dividends ​ (530) ​ — ​ (1,061) ​ ​ — Less: Series B accumulated dividends ​ (763) ​ — ​ (763) ​ ​ — Net loss available to common stockholders, basic and diluted ​ $ (3,530) ​ $ (3,533) ​ $ (11,434) ​ $ (8,291) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Denominator ​ ​ ​ ​ ​ ​ ​ ​ Weighted average shares used in computing basic and diluted net loss per share available to common stockholders ​ 11,285 ​ 10,824 ​ 11,263 ​ 10,292 Basic and diluted net loss per share of common stock ​ $ (0.31) ​ $ (0.33) ​ $ (1.02) ​ $ (0.81) ​
Outstanding Securities Considered Anti-Dilutive	The following table shows the weighted-average outstanding securities considered anti-dilutive and therefore excluded from the computation of diluted net loss per share attributable to common stockholders (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, ​ Six Months Ended June 30, ​ 2021 2020 2021 2020 Convertible preferred stock ​ 5,003 ​ 5,196 ​ 5,003 ​ 5,726 Common stock options 377 564 318 ​ 578 Warrants for common stock 5 19 5 ​ 19 Total 5,385 5,779 5,326 6,323

Royalty Purchase Agreements (Ta

Royalty Purchase Agreements (Tables)	6 Months Ended
	Jun. 30, 2021
Royalty Purchase Agreements
Summary of Acquisition of Royalty Rights	The following table summarizes the long-term royalty receivable activities including acquisitions of royalty rights during the six months ended June 30, 2021 (in thousands): ​ ​ ​ ​ Balance at December 31, 2020 $ 34,575 Acquisition of royalty rights: ​ ​ ​ Viracta ​ 13,500 Balance at June 30, 2021 ​ $ 48,075

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2021
Fair Value Measurements
Schedule of Financial Assets and Liabilities Carried at Fair Value on Recurring Basis	The following tables set forth the Company’s fair value hierarchy for its financial assets and liabilities measured at fair value on a recurring basis as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements at June 30, 2021 Using ​ ​ Quoted Prices in ​ Significant Other ​ Significant ​ ​ ​ ​ ​ Active Markets for ​ Observable ​ Unobservable ​ ​ ​ ​ ​ Identical Assets ​ Inputs ​ Inputs ​ ​ ​ ​ (Level 1) (Level 2) (Level 3) Total Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Equity securities ​ $ 2,310 ​ $ — ​ $ — ​ $ 2,310 Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contingent consideration ​ $ — ​ $ — ​ $ 75 ​ $ 75 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Measurements at December 31, 2020 Using ​ ​ Quoted Prices in ​ Significant Other ​ Significant ​ ​ ​ ​ ​ Active Markets for ​ Observable ​ Unobservable ​ ​ ​ ​ ​ Identical Assets ​ Inputs ​ Inputs ​ ​ ​ ​ (Level 1) (Level 2) (Level 3) Total Assets: ​ ​ ​ ​ ​ ​ ​ ​ Equity securities ​ $ — ​ $ — ​ $ 1,693 ​ $ 1,693 Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contingent consideration ​ $ — ​ $ — ​ $ 75 ​ $ 75
Summary of Changes in Estimated Fair Value of Level 3 Financial Assets	The following table reconciles the beginning and ending balance for the Level 3 financial assets recurring fair value measurement for the six months ended June 30, 2021 (in thousands): ​ ​ ​ ​ ​ ​ ​ Six Months Ended ​ ​ June 30, Balance at December 31, 2020 ​ $ 1,693 Change in fair value ​ 617 Transfer out of Level 3 ​ ​ (2,310) Balance at June 30, 2021 ​ $ —
Schedule of Estimated Fair Value of Equity Securities Assumptions	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, ​ December 31, ​ ​ ​ 2021 ​ 2020 Closing common stock price ​ $ 14.27 ​ $ 11.99 ​ ​ ​ ​ ​ ​ ​ ​ ​ Tranche 1: ​ ​ ​ ​ ​ ​ ​ Discount for lack of marketability ​ N/A (1) % ​ 12 % Estimated time to liquidity of shares ​ ​ ​ ​ 0.25 year ​ ​ ​ ​ ​ ​ ​ ​ ​ Tranche 2: ​ ​ ​ ​ ​ ​ ​ Discount for lack of marketability ​ ​ N/A (1) % ​ 14 % Estimated time to liquidity of shares ​ ​ ​ ​ ​ 0.67 years ​

Lease Agreements (Tables)

Lease Agreements (Tables)	6 Months Ended
	Jun. 30, 2021
Lease Agreements
Schedule of maturity of operating lease liabilities	The following table summarizes maturity of the Company’s operating lease liabilities as of June 30, 2021 (in thousands): ​ ​ ​ ​ ​ ​ ​ Operating Undiscounted lease payments Leases 2021 (excluding six months ended June 30, 2021) ​ $ 98 2022 ​ 202 2023 ​ 34 Thereafter ​ — Total undiscounted lease payments ​ 334 Present value adjustment ​ (14) Total net lease liabilities $ 320
Schedule of cost components of operating leases	The following table summarizes the cost components of the Company’s operating leases for the three and six months ended June 30, 2021 and 2020 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, Six Months Ended June 30, ​ 2021 ​ 2020 2021 2020 Lease costs: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating lease cost ​ $ 44 ​ $ 44 $ 88 $ 88 Variable lease cost (1) ​ 2 ​ 1 ​ 5 ​ 2 Total lease costs ​ $ 46 ​ $ 45 $ 93 ​ $ 90 (1) Under the terms of the lease agreements, the Company is also responsible for certain variable lease payments that are not included in the measurement of the lease liability. Variable lease payments include non-lease components such as common area maintenance fees.
Summary of supplemental cash flow information related to operating leases	The following information represents supplemental disclosure for the statement of cash flows related to operating leases (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ Six Months Ended June 30, ​ 2021 ​ 2020 Cash paid for amounts included in the measurement of lease liabilities ​ ​ ​ ​ Operating cash flows under operating leases ​ $ 98 ​ $ 94
Schedule of present value assumptions used in calculating the present value of lease payments	​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, ​ December 31, ​ 2021 ​ 2020 Weighted-average remaining lease term ​ ​ ​ ​ ​ ​ Operating leases ​ 1.67 years ​ ​ 2.17 years ​ Weighted-average discount rate ​ ​ ​ ​ ​ ​ Operating leases ​ 5.51 % ​ 5.51 %

Long-Term Debt and Other Fina_2

Long-Term Debt and Other Financings (Tables)	6 Months Ended
	Jun. 30, 2021
Long-Term Debt and Other Financings
Interest Expense and Amortization of Debt Issuance Costs and Discounts	Amortization of debt issuance costs and discounts are included in interest expense. Interest expense in the condensed consolidated statements of operations and comprehensive loss relates to the following debt instruments (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ ​ Six Months Ended ​ ​ ​ June 30, ​ ​ June 30, ​ ​ 2021 2020 2021 2020 SVB loan ​ $ 135 ​ $ 356 ​ ​ $ 373 ​ $ 739 ​ Novartis note ​ 37 ​ 151 ​ 88 ​ 309 Other ​ — ​ 1 ​ — ​ 2 Total interest expense ​ $ 172 ​ $ 508 ​ ​ $ 461 ​ $ 1,050 ​

Common Stock Warrants (Tables)

Common Stock Warrants (Tables)	6 Months Ended
	Jun. 30, 2021
Common Stock Warrants
Summary of Common Stock Warrants Outstanding	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Exercise Price June 30, December 31, Issuance Date ​ Expiration Date ​ Balance Sheet Classification ​ per Share ​ 2021 ​ 2020 February 2016 February 2021 Stockholders’ equity ​ $ 15.40 — 8,249 May 2018 May 2028 Stockholders’ equity ​ $ 23.69 6,332 6,332 March 2019 ​ March 2029 ​ Stockholders’ equity ​ $ 14.71 ​ 4,845 ​ 4,845 ​ ​ 11,177 19,426

Stock-based Compensation (Table

Stock-based Compensation (Tables)	6 Months Ended
	Jun. 30, 2021
Stock-based Compensation
Weighted Average Assumptions	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, ​ Six Months Ended June 30, ​ 2021 2020 2021 2020 Dividend yield 0 % 0 % 0 % 0 % Expected volatility 76 % 100 % 94 % 100 % Risk-free interest rate 1.06 % 0.40 % 0.77 % 0.77 % Expected term 6.00 years ​ 5.93 years ​ 5.68 years ​ 5.66 years ​
Stock Option Activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted Weighted ​ ​ ​ ​ ​ Average ​ Average ​ Aggregate ​ ​ ​ ​ Exercise ​ Contractual ​ Intrinsic ​ ​ Number of ​ Price ​ Term ​ Value ​ ​ shares ​ Per Share ​ (in years) ​ (in thousands) Outstanding at January 1, 2021 ​ ​ 1,827,906 ​ $ 20.66 ​ 6.31 $ 51,401 Granted ​ 176,429 ​ 37.62 ​ ​ Exercised ​ (73,575) ​ 13.35 ​ ​ Forfeited, expired or cancelled ​ ​ (57,115) ​ 71.26 ​ ​ Outstanding at June 30, 2021 ​ ​ 1,873,645 ​ $ 21.00 ​ 6.19 ​ $ 33,125 Exercisable at June 30, 2021 ​ ​ 1,535,686 ​ $ 19.37 ​ 5.58 ​ $ 30,459
Stock-based Compensation Expense	The following table shows total stock-based compensation expense for stock options and ESPP in the condensed consolidated statements of operations and comprehensive loss (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, ​ Six Months Ended June 30, ​ 2021 2020 2021 2020 Research and development ​ $ — ​ $ — ​ $ — ​ $ — General and administrative ​ 768 ​ 773 ​ 3,666 ​ 2,561 Total stock-based compensation expense ​ $ 768 ​ $ 773 ​ $ 3,666 ​ $ 2,561

Description of Business - Cash

Description of Business - Cash and Restricted Cash (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Description of Business
Unrestricted and restricted cash	$ 83,785	$ 86,364	$ 49,491	$ 56,688

Description of Business - Stock

Description of Business - Stock Issuance (Details) - shares	Apr. 09, 2021	Dec. 15, 2020	Jun. 30, 2021	Dec. 31, 2020
8.625% Series A Cumulative, Perpetual Preferred Stock
Stock
Preferred stock, dividend rate (as a percent)		8.625%	8.625%	8.625%
8.375% Series B Cumulative, Perpetual Preferred Stock
Stock
Preferred stock, dividend rate (as a percent)	8.375%		8.375%	8.375%
Depositary share's fractional interest in share of preferred stock	0.001
8.375% Series B Cumulative, Perpetual Preferred Stock | Public Offering of Depository Shares and Series B Preferred Shares
Stock
Preferred stock, dividend rate (as a percent)			8.375%
Depositary share's fractional interest in share of preferred stock			0.001

Description of Business - Repay

Description of Business - Repayment of Debt (Details) $ in Millions	6 Months Ended
	Jun. 30, 2021USD ($)
Silicon Valley Bank And Novartis Pharma AG
Long-term debt
Repayments of debt	$ 17.1

Basis of Presentation and Sig_4

Basis of Presentation and Significant Accounting Policies - Use of Estimates (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Basis of Presentation and Significant Accounting Policies
Contingent liabilities	$ 1,410	$ 1,410

Basis of Presentation and Sig_5

Basis of Presentation and Significant Accounting Policies - Cash and Restricted Cash (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Basis of Presentation and Significant Accounting Policies
Cash	$ 78,945	$ 84,222	$ 49,491
Restricted cash	4,840
Total cash and restricted cash	$ 83,785	$ 86,364	$ 49,491	$ 56,688

Basis of Presentation and Sig_6

Basis of Presentation and Significant Accounting Policies - Equity Securities (Details)	1 Months Ended	3 Months Ended
	Oct. 31, 2020shares	Dec. 31, 2020shares	Sep. 30, 2020shares
Rezolute
Equity investments
Number of shares owned	161,860	161,860	8,093,010
Rezolute
Equity investments
Reverse stock split	0.02	0.02

Basis of Presentation and Sig_7

Basis of Presentation and Significant Accounting Policies - Purchase of Rights to Future Milestones and Royalties and Income Taxes and Net Income (Loss) per Share (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Purchase of Rights to Future Milestones and Royalties
Impairment of long-term royalty receivable	$ 0	$ 0
Income tax penalties or interest charged	$ 0

Basis of Presentation and Sig_8

Basis of Presentation and Significant Accounting Policies - Concentration of Risk (Details) $ in Millions	Dec. 31, 2020customer	Jun. 30, 2021USD ($)customer	Jun. 30, 2020customer	Jun. 30, 2021USD ($)customer	Jun. 30, 2020customer
Concentration of Risk
Trade receivable, net | $		$ 0		$ 0
Customer Concentration Risk | Revenues
Concentration of Risk
Number of major partners		2	1	2	2
Customer Concentration Risk | Revenues | Partner 1
Concentration of Risk
Concentration risk (as a percent)		55.00%	88.00%	57.00%	56.00%
Customer Concentration Risk | Revenues | Partner 2
Concentration of Risk
Concentration risk (as a percent)		42.00%		39.00%	40.00%
Credit Concentration Risk | Trade Receivables | Partner 1
Concentration of Risk
Number of major partners	1
Concentration risk (as a percent)	100.00%

Basis of Presentation and Sig_9

Basis of Presentation and Significant Accounting Policies - Accounting Pronouncements (Details)	Jan. 01, 2021
ASU 2019-12
Adopted Accounting Pronouncements
Change in Accounting Principle, Accounting Standards Update, Adopted	true
ASU 2020-06
Adopted Accounting Pronouncements
Change in Accounting Principle, Accounting Standards Update, Adopted	true
ASU 2020-04
Adopted Accounting Pronouncements
Change in Accounting Principle, Accounting Standards Update, Adopted	true

Condensed Consolidated Financ_3

Condensed Consolidated Financial Statements Detail - Equity Securities (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Equity Securities
Long-term equity securities					$ 1,693
Gain (loss) recognized due to change in fair value of investment			$ 617	$ (150)
Rezolute
Equity Securities
Long-term equity securities	$ 2,300		2,300		$ 1,700
Gain (loss) recognized due to change in fair value of investment	$ 1,300	$ 100	$ 600	$ (200)

Condensed Consolidated Financ_4

Condensed Consolidated Financial Statements Detail - Accrued and Other Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Accrued and other liabilities
Accrued legal and accounting fees	$ 454	$ 351
Accrued incentive compensation	466	71
Accrued payroll and other	139	220
Total	$ 1,059	$ 642

Condensed Consolidated Financ_5

Condensed Consolidated Financial Statements Details - Net Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
Numerator
Net loss	$ (2,237)	$ (7,373)	$ (3,533)	$ (4,758)	$ (9,610)	$ (8,291)
Less: accumulated dividends	(1,293)				(1,824)
Net (loss) income available to common stockholders, basic	(3,530)		(3,533)		(11,434)	(8,291)
Net (loss) income available to common stockholders, diluted	$ (3,530)		$ (3,533)		$ (11,434)	$ (8,291)
Denominator
Weighted average shares used in computing basic net loss per share available to common stockholders	11,285		10,824		11,263	10,292
Weighted average shares used in computing diluted net income (loss) per share available to common stockholders	11,285		10,824		11,263	10,292
Basic net (loss) income per share of common stock	$ (0.31)		$ (0.33)		$ (1.02)	$ (0.81)
Diluted net (loss) income per share of common stock	$ (0.31)		$ (0.33)		$ (1.02)	$ (0.81)
8.625% Series A Cumulative, Perpetual Preferred Stock
Numerator
Less: accumulated dividends	$ (530)				$ (1,061)
8.375% Series B Cumulative, Perpetual Preferred Stock
Numerator
Less: accumulated dividends	$ (763)				$ (763)

Condensed Consolidated Financ_6

Condensed Consolidated Financial Statements Details - Outstanding Securities Considered Anti-Dilutive (Details) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Antidilutive Securities Excluded From Computation Of Earnings Per Share
Antidilutive securities excluded from computation of net loss per share (in shares)	5,385	5,779	5,326	6,323
Convertible preferred stock.
Antidilutive Securities Excluded From Computation Of Earnings Per Share
Antidilutive securities excluded from computation of net loss per share (in shares)	5,003	5,196	5,003	5,726
Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share
Antidilutive securities excluded from computation of net loss per share (in shares)	377	564	318	578
Warrants for common stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share
Antidilutive securities excluded from computation of net loss per share (in shares)	5	19	5	19

Licensing and Other Arrangeme_2

Licensing and Other Arrangements - Novartis International (Details) $ in Thousands	Oct. 21, 2020USD ($)	Sep. 30, 2015item	Jun. 30, 2021USD ($)	Sep. 30, 2015USD ($)	Jun. 30, 2021USD ($)	Jun. 30, 2020USD ($)	Jun. 30, 2021USD ($)	Jun. 30, 2020USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2020USD ($)
Licensing and other arrangements
Revenue from contracts with customers					$ 525	$ 53	$ 544	$ 553
Novartis Note
Licensing and other arrangements
Reduction in debt obligation	$ 7,300		$ 9,100
Novartis International | License Agreement
Licensing and other arrangements
Agreement termination prior written notice period		180 days
Number of performance obligations | item		1
Cash payment received	17,700									$ 37,000
Revenue from contracts with customers	25,000				0	$ 0	0	$ 0	$ 10,000	$ 37,000
Maximum eligible milestone payments receivable upon achievement of development, regulatory and commercial milestones	$ 445,000			$ 480,000
Royalty payment period		10 years
Contract assets			0		0		0				$ 0
Contract liabilities			0		0		0				0
Capitalized contract costs			$ 0		$ 0		$ 0				$ 0

Licensing and Other Arrangeme_3

Licensing and Other Arrangements - Novartis - Gevokizumab and IL-1 Beta (Details) $ / shares in Units, $ in Thousands, € in Millions	Aug. 24, 2017USD ($)agreementitem$ / sharesshares	Aug. 24, 2017EUR (€)agreementitemshares	Jun. 30, 2021USD ($)	Jun. 30, 2020USD ($)	Jun. 30, 2021USD ($)	Jun. 30, 2020USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2020USD ($)
Licensing and other arrangements
Proceeds from issuance of common stock						$ 26
Revenue from contracts with customers			$ 525	$ 53	$ 544	553
Novartis Pharma AG | Gevokizumab License Agreement and IL-1 Target License Agreement
Licensing and other arrangements
Transaction price	$ 40,200
Cash payment received	25,700
License agreement consideration received, repayment of debt	14,300
Common stock premium	$ 200
Number of license agreements | agreement	2	2
Number of arrangements | item	1	1
Number of performance obligations | item	2	2
Remaining performance obligations			0		0
Revenue from contracts with customers			0	$ 0	0	$ 0	$ 40,200
Contract assets			0		0			$ 0
Contract liabilities			0		0			0
Capitalized contract costs			$ 0		$ 0			$ 0
Novartis Pharma AG | Gevokizumab License Agreement
Licensing and other arrangements
License agreement consideration received	$ 30,000
Cash payment received	15,700
License agreement consideration received, repayment of debt	14,300	€ 12
Proceeds from issuance of common stock	5,000
Common stock premium	200
Maximum eligible milestone payments receivable upon achievement of development, regulatory and commercial milestones	$ 438,000
Agreement termination prior written notice period	6 months	6 months
Novartis Pharma AG | Gevokizumab License Agreement | Common Stock
Licensing and other arrangements
Shares issued (in shares) | shares	539,131	539,131
Purchase price (in dollars per share) | $ / shares	$ 9.2742
Issuance of common stock, fair value	$ 4,800
Closing stock price (in dollars per share) | $ / shares	$ 8.93
Novartis Pharma AG | IL-1 Target License Agreement
Licensing and other arrangements
Cash payment received	$ 10,000

Licensing and Other Arrangeme_4

Licensing and Other Arrangements - Takeda (Details) - USD ($) $ in Thousands	Nov. 16, 2020	Feb. 28, 2009	Nov. 30, 2006	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Licensing and other arrangements
Revenue from contracts with customers				$ 525	$ 53	$ 544	$ 553
Takeda | Collaboration agreement
Licensing and other arrangements
Revenue from contracts with customers	$ 2,000			0	$ 0	0	$ 0
Contract assets				0		0		$ 0
Capitalized contract costs				$ 0		$ 0		$ 0
Takeda | Collaboration agreement | TAK-079
Licensing and other arrangements
Maximum eligible milestone payments receivable upon achievement of development, regulatory and commercial milestones			$ 19,000
Royalty payment period from the first commercial sale of each royalty-bearing discovery product			13 years 6 months
Royalty payment period from first commercial sale if there is significant generic competition post patent-expiration			12 years
Takeda | Collaboration agreement | Other antibodies
Licensing and other arrangements
Maximum eligible milestone payments receivable per discovery product candidate		$ 3,300
Royalty payment period		10 years

Licensing and Other Arrangeme_5

Licensing and Other Arrangements - Rezolute (Details) $ in Thousands	Dec. 06, 2017USD ($)	Oct. 31, 2020shares	Jun. 30, 2021USD ($)	Dec. 31, 2020USD ($)shares	Jun. 30, 2020USD ($)	Jun. 30, 2021USD ($)	Jun. 30, 2020USD ($)	Oct. 31, 2020USD ($)shares	Sep. 30, 2020shares
Licensing and other arrangements
Revenue recognized			$ 525		$ 53	$ 544	$ 553
Rezolute
Licensing and other arrangements
Number of shares owned | shares		161,860		161,860				161,860	8,093,010
Rezolute | License Agreement and Common Stock Purchase Agreement
Licensing and other arrangements
License agreement consideration received	$ 0
Payments received upon achievement of financing activities								$ 6,000
Installment payments received								$ 8,500
Number of shares received | shares								8,093,010
Contract assets			0	$ 0		0
Contract liabilities			0	0		0
Capitalized contract costs			0	$ 0		0
Rezolute | License Agreement
Licensing and other arrangements
Percentage of decrease in future royalty obligations	20.00%
Agreement termination prior written notice period	90 days
Revenue recognized			$ 0		$ 0	$ 0	$ 0
Rezolute | License Agreement, RZ358
Licensing and other arrangements
Maximum eligible milestone payments receivable upon achievement of development, regulatory and commercial milestones	$ 232,000
Royalty payment period	12 years
Rezolute | License Agreement, Non-RZ358 products
Licensing and other arrangements
Royalty payment period	12 years
Rezolute
Licensing and other arrangements
Reverse stock split		0.02		0.02

Licensing and Other Arrangeme_6

Licensing and Other Arrangements - Janssen Biotech (Details) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended		6 Months Ended		12 Months Ended
	May 31, 2021	Aug. 31, 2019	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2019	Dec. 31, 2020
Licensing and other arrangements
Revenue from contracts with customers			$ 525	$ 53	$ 544	$ 553
Janssen Biotech Inc. | License Agreement
Licensing and other arrangements
Cash payment received		$ 2,500
Maximum amount receivable milestone payments upon achievement of certain clinical development and regulatory approval events		$ 3,000
Percentage of royalty on worldwide net sales of each product upon commercialization		0.75%
Revenue from contracts with customers	$ 500		500	$ 0	500	$ 0	$ 2,500
Contract assets			0		0			$ 0
Contract liabilities			0		0			0
Capitalized contract costs			$ 0		$ 0			$ 0

Licensing and Other Arrangeme_7

Licensing and Other Arrangements - Affimed (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Licensing and other arrangements
Revenue from contracts with customers	$ 525	$ 53	$ 544	$ 553
Affimed
Licensing and other arrangements
Contract assets	0		0
Contract liabilities	0		0
Capitalized contract costs	0		0
Revenue from contracts with customers	$ 0		$ 0

Licensing and Other Arrangeme_8

Licensing and Other Arrangements - NIAID (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Sep. 30, 2008	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2017	Dec. 31, 2014
Licensing and other arrangements
Revenue recognized		$ 525	$ 53	$ 544	$ 553
Contingent liabilities		1,410		1,410		$ 1,410
Arrangement with Governmental Agency | NIAID
Licensing and other arrangements
Total contract amount awarded	$ 64,800
Contractual term	3 years
Accounts receivable								$ 400
Deferred revenue/Contract liabilities								$ 800
Accounts receivable written off							$ 400
Estimated refund liability						1,400
Revenue recognized						(600)
Contingent liabilities		$ 1,400		$ 1,400		$ 1,400

Licensing and Other Arrangeme_9

Licensing and Other Arrangements - Sale of Future Revenue Streams (Details) $ in Thousands	Dec. 21, 2016USD ($)agreementperiod	Jun. 30, 2021USD ($)	Jun. 30, 2020USD ($)	Jun. 30, 2021USD ($)	Jun. 30, 2020USD ($)	Dec. 31, 2020USD ($)
Licensing and other arrangements
Unearned revenue recognized under units-of-revenue method				$ (731)	$ (695)
Revenue recognized under units-of-revenue method		$ 376	$ 391	731	695
Unearned revenue recognized under units-of-revenue method, current		1,503		1,503		$ 1,452
Unearned revenue recognized under units-of-revenue method, noncurrent		12,734		12,734		$ 13,516
HealthCare Royalty Partners II, L.P
Licensing and other arrangements
Revenue recognized under units-of-revenue method		400	$ 400	700	$ 700
Unearned revenue recognized under units-of-revenue method, current		1,500		1,500
Unearned revenue recognized under units-of-revenue method, noncurrent		$ 12,700		$ 12,700
HealthCare Royalty Partners II, L.P | Royalty Sale Agreements
Licensing and other arrangements
Number of agreements | agreement	2
Unearned revenue recognized under units-of-revenue method	$ 18,000
HealthCare Royalty Partners II, L.P | First Royalty Sale Agreement
Licensing and other arrangements
Cash payment received	6,500
Eligible potential additional payments receivable upon achievement of specified net sales milestones in future years	$ 4,000
Number of milestone periods | period	3
HealthCare Royalty Partners II, L.P | Second Royalty Sale Agreement
Licensing and other arrangements
Cash payment received	$ 11,500

Royalty Purchase Agreements - A

Royalty Purchase Agreements - Agenus (Details) $ in Thousands	Sep. 20, 2018USD ($)product	Nov. 30, 2020USD ($)	Jun. 30, 2021USD ($)	Jun. 30, 2020USD ($)	Jun. 30, 2021USD ($)	Jun. 30, 2020USD ($)	Dec. 31, 2020USD ($)
Agreements
Payments to acquire milestones and royalties					$ 13,500
Long-term royalty receivables			$ 48,075		48,075		$ 34,575
Revenue from contracts with customers			$ 525	$ 53	544	$ 553
Impairment of long-term royalty receivable					0		$ 0
Royalty Purchase Agreement | Merck Immuno-Oncology Product | Agenus
Agreements
Amount of milestone achieved		$ 10,000
Agenus | Royalty Purchase Agreement
Agreements
Payments to acquire milestones and royalties	$ 15,000
Long-term royalty receivables	15,000
Impairment of long-term royalty receivable					$ 0
Agenus | Royalty Purchase Agreement | Silicon Valley Bank Loans
Agreements
Proceeds from issuance of long-term debt	$ 7,500
Agenus | Royalty Purchase Agreement | Incyte Immuno-Oncology Assets
Agreements
Royalties entity has right to receive (as a percent)	33.00%
Number of licensed products related to milestone and royalties | product	6
Purchased percentage of milestones	10.00%
Agenus | Royalty Purchase Agreement | Merck Immuno-Oncology Product
Agreements
Royalties entity has right to receive (as a percent)	33.00%
Purchased percentage of milestones	10.00%
Purchased eligible milestone payments receivable upon achievement of potential development, regulatory and commercial milestones	$ 59,500
Amount of milestone achieved		1,000
Cash receipts for achievement of contractual milestones		$ 1,000

Royalty Purchase Agreements - B

Royalty Purchase Agreements - Bioasis (Details) $ in Thousands	Nov. 02, 2020USD ($)	Feb. 25, 2019USD ($)agreement	Jun. 30, 2021USD ($)	Dec. 31, 2020USD ($)
Agreements
Payments to acquire milestones and royalties			$ 13,500
Long-term royalty receivables			48,075	$ 34,575
Contingent consideration under royalty purchase agreements			75	75
Impairment of long-term royalty receivable			0	$ 0
Bioasis Technologies Inc | Royalty Purchase Agreement
Agreements
Percentage of option to purchase royalty right on future license agreements		1.00%
Number of future license agreements under optional purchase right | agreement		2
Obligation upon exercise of options per licensed product, second agreement		$ 300
Obligation upon exercise of options per licensed product, third agreement		400
Payments to acquire milestones and royalties		300
Long-term royalty receivables		400
Contingent consideration under royalty purchase agreements		100
Changes in estimated fair value of contingent consideration			0
Payments of contingent consideration			0
Impairment of long-term royalty receivable			0
Bioasis Technologies Inc | Royalty Purchase Agreement | Maximum
Agreements
Potential future cash payments		$ 200
Bioasis Technologies Inc | Second Royalty Purchase Agreement
Agreements
Payments to acquire milestones and royalties	$ 1,200
Long-term royalty receivables	$ 1,200
Impairment of long-term royalty receivable			$ 0

Royalty Purchase Agreements -_2

Royalty Purchase Agreements - Aronora (Details) $ in Thousands	Apr. 07, 2019USD ($)item	Sep. 30, 2019USD ($)	Jun. 30, 2021USD ($)	Dec. 31, 2020USD ($)
Agreements
Long-term royalty receivables			$ 48,075	$ 34,575
Contingent consideration under royalty purchase agreements			75	75
Impairment of long-term royalty receivable			0	$ 0
Aronora | Royalty Purchase Agreement
Agreements
Number of drug candidates | item	5
Non-royalties to be received (as a percent)	10.00%
Future non-royalty payments to be received (as a percent)	5.00%
Multiplier for cumulative amount of consideration paid | item	2
Upfront payment	$ 6,000
Threshold amount of cumulative royalties on net sales per product	250,000
Aggregate milestones payments per product	85,000
Long-term royalty receivables	9,000
Contingent consideration under royalty purchase agreements	3,000		0
Payments of contingent consideration		$ 3,000
Impairment of long-term royalty receivable			$ 0
Aronora | Royalty Purchase Agreement | Silicon Valley Bank Loans
Agreements
Upfront payment	$ 3,000
Aronora | Royalty Purchase Agreement | Bayer Products
Agreements
Number of drug candidates | item	3
Number of drug candidates subject to exclusive license option | item	1
Royalties entity has right to receive (as a percent)	100.00%
Non-royalties to be received (as a percent)	10.00%
Contingent future cash payment for each product	$ 1,000
Potential future cash payments	$ 3,000
Aronora | Royalty Purchase Agreement | Non-Bayer Products
Agreements
Number of drug candidates | item	2
Non-royalties to be received (as a percent)	10.00%

Royalty Purchase Agreements - P

Royalty Purchase Agreements - Palobiofarma (Details) $ in Thousands	Sep. 26, 2019USD ($)item	Jun. 30, 2021USD ($)	Dec. 31, 2020USD ($)
Agreements
Payments to acquire milestones and royalties		$ 13,500
Long-term royalty receivables		48,075	$ 34,575
Impairment of long-term royalty receivable		0	$ 0
Palobiofarma, S.L. | Royalty Purchase Agreement
Agreements
Number of drug candidates | item	6
Payments to acquire milestones and royalties	$ 10,000
Long-term royalty receivables	10,000
Impairment of long-term royalty receivable		$ 0
Palobiofarma, S.L. | Royalty Purchase Agreement | Silicon Valley Bank Loans
Agreements
Proceeds from issuance of long-term debt	$ 5,000

Royalty Purchase Agreements - V

Royalty Purchase Agreements - Viracta (Details) $ in Thousands	Mar. 22, 2021USD ($)item	Jun. 30, 2021USD ($)	Dec. 31, 2020USD ($)
Agreements
Payments to acquire milestones and royalties		$ 13,500
Long-term royalty receivables		48,075	$ 34,575
Impairment of long-term royalty receivable		0	$ 0
Viracta | Royalty Purchase Agreement
Agreements
Number of drug candidates | item	2
Maximum amount of potential milestones and other payments receivable	$ 54,000
Amount of maximum consideration retained	20,000
Maximum amount of potential regulatory and commercial milestones receivable	57,000
Payments to acquire milestones and royalties	13,500
Long-term royalty receivables	$ 13,500
Impairment of long-term royalty receivable		$ 0

Royalty Purchase Agreements - S

Royalty Purchase Agreements - Summary of Acquisition of Royalty Rights (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2021USD ($)
Agreements
Balance at beginning of period	$ 34,575
Balance at end of period	48,075
Viracta
Agreements
Acquisition of royalty rights	$ 13,500

Fair Value Measurements - Finan

Fair Value Measurements - Financial Assets and Liabilities Carried at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Transfers between Levels
Transfer into Level 3	$ 0		$ 0
Transfer out of Level 3	0		0
Level 2 to Level 1 transfers, Assets	0		0
Level 1 to Level 2 transfers, Liabilities	0		0
Level 2 to Level 1 transfers, Liabilities	$ 0		$ 0
Significant Unobservable Inputs (Level 3)
Transfers between Levels
Transfer out of Level 3		$ 2,310
Recurring
Assets:
Equity securities		2,310		$ 1,693
Liabilities:
Contingent consideration		75		75
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Equity securities		2,310
Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Equity securities				1,693
Liabilities:
Contingent consideration		$ 75		$ 75

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Changes In Estimated Fair Value of Level 3 Financial Assets (Details) $ in Thousands	Jan. 01, 2020shares	Jun. 30, 2020USD ($)	Jun. 30, 2021USD ($)	Jun. 30, 2020USD ($)	Dec. 31, 2020item
Changes in the estimated fair value of Level 3 financial assets
Transfer out of Level 3		$ 0		$ 0
Significant Unobservable Inputs (Level 3)
Changes in the estimated fair value of Level 3 financial assets
Balance at beginning of period			$ 1,693
Change in fair value			617
Transfer out of Level 3			$ (2,310)
License Agreement and Common Stock Purchase Agreement | Rezolute
Changes in the estimated fair value of Level 3 financial assets
Number of Rezolute's post-split shares Company has right and option to sell | shares	100,000
Number of tranches | item					2

Fair Value Measurements - Estim

Fair Value Measurements - Estimated Fair Value of Equity Securities Assumptions (Details)	Jun. 30, 2021$ / shares	Dec. 31, 2020Y$ / shares
Closing common stock price
Fair Value Measurements
Valuation assumptions, measurement input | $ / shares	14.27	11.99
Discount for lack of marketability | Tranche 1
Fair Value Measurements
Valuation assumptions, measurement input		0.12
Discount for lack of marketability | Tranche 2
Fair Value Measurements
Valuation assumptions, measurement input		0.14
Estimated time to liquidity of shares | Tranche 1
Fair Value Measurements
Valuation assumptions, measurement input | Y		0.25
Estimated time to liquidity of shares | Tranche 2
Fair Value Measurements
Valuation assumptions, measurement input | Y		0.67
Rezolute
Fair Value Measurements
Closing stock price (in dollars per share) | $ / shares	$ 14.27	$ 11.99

Fair Value Measurements - Conti

Fair Value Measurements - Contingent Consideration (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Dec. 31, 2020	Feb. 25, 2019
Fair Value Measurements
Contingent consideration under royalty purchase agreements	$ 75	$ 75
Bioasis Technologies Inc | Royalty Purchase Agreement
Fair Value Measurements
Changes in estimated fair value of contingent consideration	$ 0
Contingent consideration under royalty purchase agreements			$ 100

Lease Agreements - Leased facil

Lease Agreements - Leased facilities (Details)	6 Months Ended
	Jun. 30, 2021facility
Leased facilities, Emeryville, California
Leases
Operating leases, number of leased facilities	1

Lease Agreements - Maturity of

Lease Agreements - Maturity of lease liabilities (Details) $ in Thousands	Jun. 30, 2021USD ($)
Lease Agreements
2021 (excluding six months ended June 30, 2021)	$ 98
2022	202
2023	34
Total undiscounted lease payments	334
Present value adjustment	(14)
Total net lease liabilities	$ 320

Lease Agreements - Rent Expense

Lease Agreements - Rent Expense and Lease costs (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Lease costs
Operating lease cost	$ 44	$ 44	$ 88	$ 88
Variable lease cost	2	1	5	2
Total lease costs	$ 46	$ 45	$ 93	$ 90

Lease Agreements - Additional i

Lease Agreements - Additional information (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Lease Agreements
Cash paid for amounts included in the measurement of lease liabilities, Operating cash flows under operating leases	$ 98	$ 94
Weighted-average remaining lease term, Operating leases	1 year 8 months 1 day		2 years 2 months 1 day
Weighted-average discount rate, Operating leases	5.51%		5.51%

Long-Term Debt and Other Fina_3

Long-Term Debt and Other Financings - Silicon Valley Bank Loan Agreement (Details) - USD ($) $ / shares in Units, $ in Thousands	Mar. 04, 2019	May 07, 2018	Jun. 30, 2021	Sep. 30, 2018	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2019	Dec. 31, 2020
Long-term debt
Current portion of long-term debt										$ 8,088
Long-term debt										$ 12,764
Loss on extinguishment of debt					$ (300)		$ (300)
Common stock warrant, Exercise price $23.69 per share, Issued May 2018
Long-term debt
Exercise price of per share (in dollars per share)			$ 23.69		$ 23.69		$ 23.69			$ 23.69
Common stock warrant, Exercise price $14.71 per share, Issued March 2019
Long-term debt
Exercise price of per share (in dollars per share)			$ 14.71		$ 14.71		$ 14.71			$ 14.71
Silicon Valley Bank Loans
Long-term debt
Maximum borrowing capacity under loan agreement		$ 20,000
Period of monthly payments of principal and interest		24 months
Maximum period following loan amortization date for which loan will mature		23 months
Maximum period prior to loan maturity date of Novartis loan for which loan will mature		30 days
Amount of loan that may be reborrowed after repayment		$ 0
Repayments of debt			$ 6,500
Final payment fee (as a percent)		8.50%	8.50%		8.50%		8.50%
Final payment fee			$ 1,400
Prepayment fee (as a percent)			1.00%		1.00%		1.00%
Debt issuance costs		$ 200
Non-cash interest expense resulting from amortization of discount and accretion of final payment					$ 100	$ 200	$ 200	$ 400
Debt amount			$ 0		0		0			$ 11,800
Current portion of long-term debt										8,100
Long-term debt										$ 3,700
Loss on extinguishment of debt					$ 300		$ 300
Silicon Valley Bank Loans | Minimum
Long-term debt
Interest rate (as a percent)		4.75%
Silicon Valley Bank Loans | Common stock warrant, Exercise price $23.69 per share, Issued May 2018
Long-term debt
Aggregate number of shares of common stock called by warrants		6,332
Exercise price of per share (in dollars per share)		$ 23.69
Exercisable period of warrants		10 years
Fair value of warrant		$ 100
Silicon Valley Bank Loans | Common stock warrant, Exercise price $14.71 per share, Issued March 2019
Long-term debt
Aggregate number of shares of common stock called by warrants	4,845
Exercise price of per share (in dollars per share)	$ 14.71
Exercisable period of warrants	10 years
Fair value of warrant	$ 100
Silicon Valley Bank Loans | Prime Rate
Long-term debt
Basis spread on variable rate		0.25%
Silicon Valley Bank, First Term Loan
Long-term debt
Proceeds from issuance of long-term debt				$ 7,500
Unamortized discount				$ 300
Silicon Valley Bank, Second Term Loan
Long-term debt
Proceeds from issuance of long-term debt									$ 9,500
Unamortized discount									$ 45

Long-Term Debt and Other Fina_4

Long-Term Debt and Other Financings - Novartis Note (Details) - USD ($) $ in Thousands	Oct. 21, 2020	Jun. 30, 2021	May 31, 2005	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2017	Dec. 31, 2015	Dec. 31, 2020	Sep. 30, 2015
Long-term debt
Revenue from contracts with customers				$ 525	$ 53	$ 544	$ 553
Loss on extinguishment of debt				(300)		(300)
Novartis Note
Long-term debt
Research and development expenses funded through loan facility, maximum (as a percent)			75.00%
Maximum borrowing capacity under loan agreement			$ 50,000
Amount by which note will be reduced upon achievement of specified milestones											$ 7,300
Reduction in debt obligation	$ 7,300	$ 9,100
Debt amount		$ 0		0		0				$ 9,100
Loss on extinguishment of debt						0
Novartis Note | Six-month LIBOR
Long-term debt
Basis spread on variable rate			2.00%
Novartis International | License Agreement
Long-term debt
Revenue from contracts with customers	25,000			$ 0	$ 0	$ 0	$ 0	$ 10,000	$ 37,000
Cash payment received	$ 17,700								$ 37,000

Long-Term Debt and Other Fina_5

Long-Term Debt and Other Financings - Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Interest expense
Interest expense	$ 172	$ 508	$ 461	$ 1,050
Silicon Valley Bank Loans
Interest expense
Interest expense	135	356	373	739
Novartis Note
Interest expense
Interest expense	$ 37	151	$ 88	309
Other
Interest expense
Interest expense		$ 1		$ 2

Common Stock Warrants (Details)

Common Stock Warrants (Details) - $ / shares	3 Months Ended
	Mar. 31, 2021	Jun. 30, 2021	Dec. 31, 2020
Warrants
Warrant outstanding (in shares)		11,177	19,426
Common stock warrant, Exercise Price $15.40 per share, Issued February 2016
Warrants
Exercise price of warrants (in dollars per share)			$ 15.40
Warrant outstanding (in shares)			8,249
Exercise of warrant	4,917
Common stock warrant, Exercise price $23.69 per share, Issued May 2018
Warrants
Exercise price of warrants (in dollars per share)		$ 23.69	$ 23.69
Warrant outstanding (in shares)		6,332	6,332
Common stock warrant, Exercise price $14.71 per share, Issued March 2019
Warrants
Exercise price of warrants (in dollars per share)		$ 14.71	$ 14.71
Warrant outstanding (in shares)		4,845	4,845

Commitments and Contingencies -

Commitments and Contingencies - Collaborative Agreements, Royalties and Milestone Payments (Details) $ in Millions	Jun. 30, 2021USD ($)product
Commitments and Contingencies
Estimate of milestone payments | $	$ 7.6
Assumed number of products per contract | product	1

Commitments and Contingencies_2

Commitments and Contingencies - Contingent Consideration (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Dec. 31, 2020	Apr. 07, 2019	Feb. 25, 2019
Commitments And Contingencies
Contingent consideration under royalty purchase agreements	$ 75	$ 75
Royalty Purchase Agreement | Bioasis Technologies Inc
Commitments And Contingencies
Contingent consideration under royalty purchase agreements				$ 100
Change in fair value	0
Royalty Purchase Agreement | Aronora
Commitments And Contingencies
Contingent consideration under royalty purchase agreements	0		$ 3,000
Change in fair value	$ 0

Stock-based Compensation - ESPP

Stock-based Compensation - ESPP (Details)	6 Months Ended
	Jun. 30, 2021
2015 ESPP
Share-based compensation
Percentage related to employees to purchase shares at the lower fair market value at offering period	85.00%

Stock-based Compensation - Stoc

Stock-based Compensation - Stock Options (Details) - Stock Options	6 Months Ended
	Jun. 30, 2021
Share-based compensation
Minimum age required for employees to qualify for immediate vesting of award	55 years
Threshold years required for retirement age	70 years
Employees
Share-based compensation
Vesting period	3 years
Directors
Share-based compensation
Vesting period	1 year

Stock-based Compensation - Weig

Stock-based Compensation - Weighted Average Assumptions (Details) - Stock Options	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Weighted average assumptions
Dividend yield	0.00%	0.00%	0.00%	0.00%
Expected volatility	76.00%	100.00%	94.00%	100.00%
Risk-free interest rate	1.06%	0.40%	0.77%	0.77%
Expected term	6 years	5 years 11 months 4 days	5 years 8 months 4 days	5 years 7 months 28 days

Stock-based Compensation - St_2

Stock-based Compensation - Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Share-based compensation
Number of shares, Outstanding at beginning of period	1,827,906
Number of shares, Granted	176,429
Number of shares, Exercised	(73,575)
Number of shares, Forfeited, expired or cancelled	(57,115)
Number of shares, Outstanding at end of period	1,873,645		1,827,906
Number of shares, Exercisable at end of period	1,535,686
Weighted Average Exercise Price Per Share, Outstanding at beginning of period	$ 20.66
Weighted Average Exercise Price Per Share, Granted	37.62
Weighted Average Exercise Price Per Share, Exercised	13.35
Weighted Average Exercise Price Per Share, Forfeited, expired or cancelled	71.26
Weighted Average Exercise Price Per Share, Outstanding at end of period	21		$ 20.66
Weighted Average Exercise Price Per Share, Exercisable at end of period	$ 19.37
Weighted Average Contractual Term, Outstanding	6 years 2 months 8 days		6 years 3 months 21 days
Weighted Average Contractual Term, Exercisable	5 years 6 months 29 days
Aggregate Intrinsic Value, Outstanding	$ 33,125		$ 51,401
Aggregate Intrinsic Value, Exercisable	30,459
Options exercised, aggregate intrinsic value	$ 1,500	$ 40
Stock Options
Share-based compensation
Weighted-average grant-date fair value (in dollars per share)	$ 27.89	$ 16.22
Unrecognized compensation expense related to stock options (in dollars)	$ 4,300
Weighted average period of unrecognized compensation expense expected to be recognized	1 year 8 months 23 days

Stock-based Compensation - St_3

Stock-based Compensation - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Share-based compensation expense
Stock-based compensation expense	$ 768	$ 773	$ 3,666	$ 2,561
General and administrative
Share-based compensation expense
Stock-based compensation expense	$ 768	$ 773	$ 3,666	$ 2,561

Capital Stock - Series X and Se

Capital Stock - Series X and Series Y Convertible Preferred Stock (Details) - USD ($) $ / shares in Units, $ in Millions	Feb. 28, 2017	Dec. 31, 2018	Dec. 31, 2017	Jun. 30, 2021
Series X and Series Y Convertible Preferred Stock
Sale of stock
Number of shares issued for each share of convertible preferred stock that is converted		1,000
Series X Convertible Preferred Stock
Sale of stock
Shares issued (in shares)			5,003
Preferred stock, shares outstanding (in shares)				5,003
Preferred stock conversion price per share			$ 4.03
Fair value of common stock amount exceeded purchase price of convertible preferred stock	$ 5.6
Series Y Convertible Preferred Stock
Sale of stock
Shares issued (in shares)		1,252.772
Preferred stock, shares outstanding (in shares)				0
Preferred stock conversion price per share		$ 13

Capital Stock - Series A Prefer

Capital Stock - Series A Preferred Stock (Details) $ / shares in Units, $ in Thousands	Dec. 15, 2020USD ($)MD$ / sharesshares	Jun. 30, 2021USD ($)$ / shares	Jun. 30, 2020USD ($)	Dec. 31, 2020$ / shares	Dec. 15, 2025$ / shares	Dec. 15, 2024$ / shares	Dec. 15, 2023$ / shares	Dec. 15, 2022$ / shares	Dec. 15, 2021$ / shares
Sale of stock
Gross proceeds from issuance of preferred stock | $		$ 40,000
Stock issuance costs | $		$ 3,106	$ 211
Preferred stock, par value (in dollars per share)		$ 0.05		$ 0.05
8.625% Series A Cumulative, Perpetual Preferred Stock
Sale of stock
Shares issued (in shares) | shares	984,000
Preferred stock, dividend rate (as a percent)	8.625%	8.625%		8.625%
Purchase price (in dollars per share)	$ 25
Gross proceeds from issuance of preferred stock | $	$ 24,600
Stock issuance costs | $	2,000
Net proceeds from issuance of stock | $	$ 22,600
Liquidation preference (in dollars per share)	$ 25
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
Preferred stock, par value (in dollars per share)	$ 0.05
Redemption price (in dollars per share)	25
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
Share cap (in shares) | shares	1.46071
Trading days | D	10
8.625% Series A Cumulative, Perpetual Preferred Stock | Directors
Sale of stock
Shares issued (in shares) | shares	200,000
Purchase price (in dollars per share)	$ 25
Gross proceeds from issuance of preferred stock | $	$ 5,000
8.625% Series A Cumulative, Perpetual Preferred Stock | Chief Executive Officer
Sale of stock
Shares issued (in shares) | shares	8,000
Purchase price (in dollars per share)	$ 25
Gross proceeds from issuance of preferred stock | $	$ 200
Forecast | 8.625% Series A Cumulative, Perpetual Preferred Stock
Sale of stock
Redemption price (in dollars per share)					$ 25	$ 25.25	$ 25.50	$ 25.75	$ 26

Capital Stock - Series B Prefer

Capital Stock - Series B Preferred Stock (Details) $ / shares in Units, $ in Thousands	Apr. 09, 2021USD ($)DM$ / sharesshares	Jun. 30, 2021USD ($)$ / sharesshares	Jun. 30, 2020USD ($)	Dec. 31, 2020$ / shares	Apr. 15, 2026$ / shares	Apr. 15, 2025$ / shares	Apr. 15, 2024$ / shares	Apr. 15, 2023$ / shares	Apr. 15, 2022$ / shares
Sale of stock
Proceeds from issuance of preferred stock | $		$ 40,000
Stock issuance costs | $		$ 3,106	$ 211
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
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
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
Share cap (in shares) | shares	1,253.13
8.375% Series B Cumulative, Perpetual Preferred Stock | Forecast
Sale of stock
Redemption price (in dollars per share)					$ 25,000	$ 25,250	$ 25,500	$ 25,750	$ 26,000
8.375% Series B Cumulative, Perpetual Preferred Stock | Public Offering of Depository Shares and Series B Preferred Shares
Sale of stock
Depositary share's fractional interest in share of preferred stock | shares		0.001
Preferred stock, dividend rate (as a percent)		8.375%
Depositary Shares
Sale of stock
Shares issued (in shares) | shares	1,600,000
Purchase price (in dollars per share)	$ 25
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
Sale of stock
Redemption price (in dollars per share)					$ 25	$ 25.25	$ 25.50	$ 25.75	$ 26
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
Proceeds from issuance of preferred stock | $	$ 200

Capital Stock - Dividends (Deta

Capital Stock - Dividends (Details) - USD ($) $ / shares in Units, $ in Thousands	Jul. 15, 2021	May 21, 2021	Apr. 15, 2021	Mar. 17, 2021	Jun. 30, 2021
Dividends
Restricted cash					$ 4,840
8.625% Series A Cumulative, Perpetual Preferred Stock
Dividends
Cash dividend declared (in dollars per share)		$ 0.53906		$ 0.71875
Cash dividend paid (in dollars per share)	$ 0.55833		$ 0.71875
Series A Preferred Stock And Series B Preferred Stock
Dividends
Restricted cash					$ 4,800

Capital Stock - BVF Ownership (

Capital Stock - BVF Ownership (Details) - BVF	Jun. 30, 2021	Feb. 29, 2020
Xoma Corporation
Sale of stock
Ownership interest (as a percent)	31.20%
Ownership interest, if shares are converted (as a percent)	52.30%
Series Y Convertible Preferred Stock
Sale of stock
Beneficial ownership limitation (as a percent)		50.00%

Capital Stock - ATM Agreements

Capital Stock - ATM Agreements (Details) - 2018 ATM Agreement - USD ($) $ in Millions	Jun. 30, 2021	Dec. 18, 2018
Sale of stock
Maximum amount of shares to be issued	$ 50	$ 30
Maximum
Sale of stock
Sales commission paid per transaction (as a percent)		3.00%
Common Stock
Sale of stock
Shares issued (in shares)	0	0

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2021	Jun. 30, 2020
Income Taxes
Income tax benefit		$ 0	$ 1,526
Cash received for income tax receivable	$ 1,500	1,500
Unrecognized tax benefits	5,900	5,900
Unrecognized tax benefits that would impact effective tax rate	0	0
Accrued interest or penalties related to uncertain tax positions	$ 0	$ 0

Subsequent Events (Details)

Subsequent Events (Details) - Subsequent Event - Kuros Biosciences AG, Kuros US LLC and Kuros Royalty Fund (US) LLC - Royalty Purchase Agreement $ in Millions	Jul. 14, 2021USD ($)
Subsequent Event [Line Items]
Royalties entity has right to receive (as a percent)	100.00%
Pre-commercial milestone payments	$ 25
Upfront payment	$ 7