0001564590-20-051302 | 10-Q | XBRL Viewer

Deferred revenue, current portion

23,945

30,051

^[1]

74,445

51,381

^[1]

Total current liabilities

102,033

85,590

^[1]

Deferred revenue, net of current portion

202,560

178,858

^[1]

Operating lease liabilities - long term

22,525

24,871

^[1]

Other long-term liabilities

^[1]

850

Total liabilities

327,118

290,169

^[1]

Commitments and contingencies (Note 11)

^[1]

Stockholders' equity:

Common stock, $0.00001 par value; 150,000,000 and 75,000,000 shares authorized at September 30, 2020 and December 31, 2019, respectively; 46,223,402 and 45,523,088 shares issued and outstanding at September 30, 2020 and December 31, 2019, respectively

^[1]

Additional paid-in capital

483,524

468,285

^[1]

Accumulated other comprehensive (loss) income

(47)

^[1]

Accumulated deficit

(435,414)

(417,230)

^[1]

Total stockholders' equity

48,064

51,113

^[1]

Total liabilities and stockholders' equity

375,182

341,282

^[1]

Convertible Preferred Stock

Stockholders' equity:

Convertible preferred stock, $0.00001 par value; 10,000,000 shares authorized and no shares issued and outstanding at September 30, 2020 and December 31, 2019.

^[1]

[1]	The condensed balance sheet as of December 31, 2019 was derived from the audited financial statements included in the Company's Annual Report on Form 10-K for the year ended December 31, 2019.

CONDENSED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement Of Income And Comprehensive Income [Abstract]
Revenues	$ 17,788	$ 10,712	$ 83,989	$ 49,210
Type of Revenue [Extensible List]	us-gaap:LicenseAndServiceMember	us-gaap:LicenseAndServiceMember	us-gaap:LicenseAndServiceMember	us-gaap:LicenseAndServiceMember
Operating expenses:
Research and development	$ 24,049	$ 27,967	$ 90,929	$ 95,178
General and administrative	8,634	8,463	26,886	27,548
Total operating expenses	32,683	36,430	117,815	122,726
Loss from operations	(14,895)	(25,718)	(33,826)	(73,516)
Interest income	200	1,997	1,730	6,854
Other income (expense), net	(15)	22	1	(126)
Loss before income taxes	(14,710)	(23,699)	(32,095)	(66,788)
Benefit from income taxes	0	0	(13,911)	(6)
Net loss	$ (14,710)	$ (23,699)	$ (18,184)	$ (66,782)
Net loss per share, basic and diluted	$ (0.32)	$ (0.52)	$ (0.40)	$ (1.47)
Shares used to compute net loss per share, basic and diluted	46,195,121	45,418,053	45,992,786	45,294,593
Other comprehensive income (loss):
Unrealized gain (loss) on short-term investments, net of tax	$ (63)	$ (99)	$ (104)	$ 192
Impact of adoption of new accounting pronouncement				11
Comprehensive loss	$ (14,773)	$ (23,798)	$ (18,288)	$ (66,579)

STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($)
$ in Thousands

Total

Common Stock

Additional Paid-in Capital

Accumulated Other Comprehensive Income/(Loss)

Cumulative Effect, Period of Adoption, Adjustment

Accumulated Deficit

Cumulative Effect, Period of Adoption, Adjustment

Beginning balance at Dec. 31, 2018

$ 130,883

$ 1

$ 445,956

$ (93)

$ 11

$ (314,981)

$ (11)

Beginning balance, shares at Dec. 31, 2018

45,083,209

Accounting Standards Update [Extensible List]

us-gaap:AccountingStandardsUpdate201409Member

$ 465

465

74,443

5,192

155

Ending balance at Mar. 31, 2019

(14,124)

122,571

$ 1

451,613

(329,116)

Ending balance, shares at Mar. 31, 2019

45,157,652

Beginning balance at Dec. 31, 2018

130,883

$ 1

445,956

(93)

$ 11

(314,981)

$ (11)

Beginning balance, shares at Dec. 31, 2018

45,083,209

192

Ending balance at Sep. 30, 2019

(66,782)

82,109

$ 1

463,773

110

(381,775)

Ending balance, shares at Sep. 30, 2019

45,426,468

Beginning balance at Mar. 31, 2019

122,571

$ 1

451,613

(329,116)

Beginning balance, shares at Mar. 31, 2019

45,157,652

Issuance of common stock under the ESPP

15,124

665

Issuance of common stock under the ESPP, shares

81,062

Issuance of common stock pursuant to license agreement

1,602

Issuance of common stock pursuant to license agreement, shares

150,000

5,454

136

Ending balance at Jun. 30, 2019

(28,960)

101,501

$ 1

459,367

209

(358,076)

Ending balance, shares at Jun. 30, 2019

45,403,838

22,630

4,343

(99)

Ending balance at Sep. 30, 2019

(23,699)

82,109

$ 1

463,773

110

(381,775)

Ending balance, shares at Sep. 30, 2019

45,426,468

Beginning balance at Dec. 31, 2019

51,113

^[1]

$ 1

468,285

(417,230)

Beginning balance, shares at Dec. 31, 2019

45,523,088

2,157

395,528

4,013

279

Ending balance at Mar. 31, 2020

12,205

69,767

$ 1

474,455

336

(405,025)

Ending balance, shares at Mar. 31, 2020

45,918,616

Beginning balance at Dec. 31, 2019

$ 51,113

^[1]

$ 1

468,285

(417,230)

Beginning balance, shares at Dec. 31, 2019

45,523,088

627,999

$ (104)

Ending balance at Sep. 30, 2020

(18,184)

48,064

$ 1

483,524

(47)

(435,414)

Ending balance, shares at Sep. 30, 2020

46,223,402

Beginning balance at Mar. 31, 2020

69,767

$ 1

474,455

336

(405,025)

Beginning balance, shares at Mar. 31, 2020

45,918,616

1,179

Issuance of common stock under the ESPP

199,139

369

Issuance of common stock under the ESPP, shares

72,315

3,513

(320)

Ending balance at Jun. 30, 2020

(15,679)

58,829

$ 1

479,516

(420,704)

Ending balance, shares at Jun. 30, 2020

46,190,070

167

33,332

3,841

(63)

Ending balance at Sep. 30, 2020

(14,710)

$ 48,064

$ 1

$ 483,524

$ (47)

$ (435,414)

Ending balance, shares at Sep. 30, 2020

46,223,402

[1]	The condensed balance sheet as of December 31, 2019 was derived from the audited financial statements included in the Company's Annual Report on Form 10-K for the year ended December 31, 2019.

CONDENSED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
CONDENSED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities:
Net loss	$ (18,184)	$ (66,782)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Amortization of intangible assets	109	109
Depreciation and amortization	1,802	1,888
Accretion of discounts on investments	(341)	(1,963)
Stock-based compensation expense	11,367	14,989
Issuance of stock in connection with UCSB sublicense fee		1,602
Changes in operating assets and liabilities
Accounts receivable	(530)	90
Prepaid expenses, income tax receivable and other current assets	(11,509)	193
Other assets	636
Accounts payable	(270)	152
Accrued liabilities, income tax payable and other long-term liabilities	(7,160)	(22,104)
Deferred revenue	46,766	(39,175)
Net cash provided by (used in) operating activities	22,686	(111,001)
Cash flows from investing activities:
Purchases of property and equipment	(1,864)	(2,794)
Purchases of short-term investments	(189,005)	(149,532)
Maturities of short-term investments	152,696	179,170
Net cash (used in) provided by investing activities	(38,173)	26,844
Cash flows from financing activities:
Proceeds from employee stock purchase plan and exercise of stock options	3,872	1,226
Net cash provided by financing activities	3,872	1,226
Net decrease in cash, cash equivalents and restricted cash	(11,615)	(82,931)
Cash, cash equivalents and restricted cash, beginning of period	189,342	248,494
Cash, cash equivalents and restricted cash, end of period	177,727	165,563
Supplemental disclosures of noncash investing items:
Purchases of property and equipment in accounts payable and accrued liabilities	$ 183	293
Right of use assets obtained in exchange for operating lease obligations		$ 28,054

Basis of Presentation and Summary of Significant Accounting Policies

9 Months Ended

Sep. 30, 2020

Accounting Policies [Abstract]

Basis of Presentation and Summary of Significant Accounting Policies

2. Basis of Presentation and Summary of Significant Accounting Policies

Basis of Presentation

The accompanying interim condensed financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and applicable rules and regulations of the U.S. Securities and Exchange Commission (“SEC”) regarding interim financial reporting.

Unaudited Interim Financial Information

The accompanying interim condensed financial statements and related disclosures are unaudited, have been prepared on the same basis as the annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for a fair statement of the results of operations for the periods presented.

The condensed balance sheet data as of December 31, 2019 was derived from audited financial statements, but does not include all disclosures required by U.S. GAAP. The condensed results of operations for the three and nine months ended September 30, 2020 are not necessarily indicative of the results to be expected for the full year or for any other future year or interim period. The accompanying condensed financial statements should be read in conjunction with the audited financial statements and the related notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2019 filed with the SEC.

Use of Estimates

The preparation of the financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements and reported amounts of revenues and expenses during the reporting periods. Actual results could differ from those estimates.

Cash and Cash Equivalents

The Company considers all highly liquid investments purchased with original maturities of three months or less at the date of purchase to be cash equivalents.

Restricted Cash

Restricted cash represents a standby letter of credit issued pursuant to an office lease entered in December 2015.

The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the condensed balance sheets that sum to the total of the amounts shown in the condensed statements of cash flows.

	September 30, 2020		December 31, 2019		September 30, 2019		December 31, 2018
	(in thousands)
Cash and cash equivalents	$	176,810	$	188,425	$	164,646	$	247,577
Restricted cash - non-current assets		917		917		917		917
Total	$	177,727	$	189,342	$	165,563	$	248,494

Short-term Investments

All investments have been classified as available-for-sale (“AFS”) and are carried at fair value as determined based upon quoted market prices or pricing models for similar securities at period end. Generally, those investments with contractual maturities less than 12 months are considered short-term investments. The amortized cost of securities is adjusted for amortization of premiums and accretion of discounts to maturity. Dividend and interest income are recognized when earned. Realized gains and losses are included in earnings and are derived using the specific identification method for determining the cost of securities sold.

The Company assesses impairment of its AFS debt securities investments at each reporting period. Unrealized gains resulting from the excess of the fair value over the amortized cost basis of an investment are reported as a component of accumulated other comprehensive income (loss), net of tax. Unrealized losses or impairments resulting from the fair value of the AFS debt security being below the amortized cost basis are evaluated, using the discounted cash flow model, for identification of credit losses and non-credit related losses. Any credit losses are charged to earnings against the allowance for credit losses of the security, limited to the difference between the fair value and the amortized cost basis of the security. Any difference between the fair value of the security and the amortized cost basis, less the allowance for credit losses, are reported in other comprehensive income (loss). Expected cash inflows due to improvements in credit are recognized through a reversal of the allowance for credit losses subject to the total allowance previously recognized.

In the event of impairment of any security, if management (i) has the intent to sell such security or (ii) will more-likely-than-not be required to sell such security before recovery of its amortized cost basis, such AFS debt security’s amortized cost basis will be written down to its fair value through earnings along with any existing allowance for credit losses.

Comprehensive Loss

Comprehensive loss represents all changes in stockholders’ equity except those resulting from distributions to stockholders. The Company’s non-credit related unrealized gains and losses on short-term investments and impact of adoption of new accounting pronouncements during the period represent the components of other comprehensive income (loss) that are excluded from the reported net loss.

Revenue Recognition

The Company’s revenues are primarily derived through its license, research, development and commercialization agreements. The terms of these types of agreements may include (i) licenses for the Company’s technology or programs, (ii) research and development services, and (iii) services or obligations in connection with participation in research or steering committees. Payments to the Company under these arrangements typically include one or more of the following: nonrefundable upfront and license fees, research funding, milestone and other contingent payments to the Company for the achievement of defined collaboration objectives and certain preclinical, clinical, regulatory and sales-based events, as well as royalties on sales of any commercialized products. The Company assesses whether the promises in its arrangements with customers are considered as distinct performance obligations that should be accounted for separately. Judgment is required to determine whether the license to the Company’s intellectual property is distinct from the research and development services or participation on steering committees.

The Company’s collaboration and license agreements may include contingent payments related to specified research, development and regulatory milestones. Such milestone payments are typically payable under the collaborations when the collaboration partner claims or selects a target, or initiates or advances a covered product candidate in preclinical or clinical development; upon submission for marketing approval of a covered product with regulatory authorities; or upon receipt of actual marketing approvals of a covered product or for additional indications. 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. At each reporting date, the Company re-evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price by using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price in such period of determination.

The Company’s collaboration and license agreements may also include contingent payments related to sales-based milestones. Sales-based milestones are typically payable when annual sales of a covered product reach specified levels. Sales-based milestones are recognized at the later of when the associated performance obligation has been satisfied or when the sales occur. Unlike other contingency payments, such as regulatory milestones, sales-based milestones are not included in the transaction price based on estimates at the inception of the contract, but rather, are included when the sales or usage occur.

The transaction price in each arrangement is allocated to the identified performance obligations based on the relative standalone selling price (“SSP”) of each distinct performance obligation, which requires judgment. In instances where SSP is not directly observable, such as when a license or service is not sold separately, SSP is determined using information that may include market conditions and other observable inputs. Due to the early stage of the Company’s licensed technology, the license of such technology is typically combined with research and development services and steering committee participation as one performance obligation. In the event that the Company receives non-cash consideration such as consideration in the form of a research license and research support services from the counterparty, the transaction price of a non-monetary exchange that has commercial substance is estimated based on the fair value of the non-cash consideration received, which may be determined through a valuation analysis.

In certain cases, the Company’s performance creates an asset that does not have an alternative use to the customer and the Company has an enforceable right to payment at all times for performance completed to date. In these cases, the Company utilizes judgment 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 and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition.

AbbVie Ireland Unlimited Company (“AbbVie”), one of the Company’s collaboration partners, entered into a license agreement with Seattle Genetics, Inc. (“SGEN”) to license certain intellectual property rights. As part of the Company’s collaboration agreement with AbbVie, the Company was required to pay SGEN sublicense fees for certain milestone achievements. These sublicense fees are treated as reductions to the transaction price and combined with the performance obligation to which they relate.

Contract Balances

Customer payments are recorded as deferred revenue upon receipt or when due and may require deferral of revenue recognition to a future period until the Company satisfies its performance obligations under these arrangements. Amounts payable to the Company are recorded as accounts receivable when the Company’s right to consideration is unconditional.

Research and Development Expenses

The Company records accrued liabilities for estimated costs of research and development activities conducted by third-party service providers, which include the conduct of preclinical and clinical studies, and contract manufacturing activities. The Company records the estimated costs of research and development activities based upon the estimated amount of services provided but not yet invoiced, and includes these costs in accrued liabilities in the balance sheets and within research and development expense in the statements of operations. These costs are a significant component of the Company’s research and development expenses. The Company accrues for these costs based on factors such as estimates of the work completed and in accordance with agreements established with its third-party service providers under the service agreements. The Company makes significant judgments and estimates in determining the accrued liabilities balance in each reporting period. As actual costs become known, the Company adjusts its accrued liabilities. The Company has not experienced any material differences between accrued costs and actual costs incurred. However, the status and timing of actual services performed may vary from the Company’s estimates, resulting in adjustments to expense in future periods. Changes in these estimates that result in material changes to the Company’s accruals could materially affect the Company’s results of operations.

Research and development expenses include costs directly attributable to the conduct of research and development programs, including the cost of salaries, payroll taxes, employee benefits, materials, supplies, depreciation on and maintenance of research equipment, the cost of services provided by outside contractors, and the allocated portions of facility costs, such as rent, utilities, insurance, repairs and maintenance, depreciation, and general support services. All costs associated with research and development are expensed as incurred.

In January 2019, the Company acquired certain technology know-how that is complementary to the Company’s proprietary Probody technology from a third party for $5.0 million. The Company plans to use this technology in certain of the Company’s discovery stage projects, and has concluded that the technology acquired does not have an alternative future use. Accordingly, the $5.0 million has been recorded as research and development expense for the nine months ended September 30, 2019.

Stock-based Compensation

The Company recognizes compensation costs related to stock options granted to employees based on the estimated fair value of the awards on the date of grant. The Company records forfeitures as they are incurred. The Company estimates the grant date fair value, and the resulting stock-based compensation expense, using the Black-Scholes option-pricing model. The grant date fair value of stock-based awards is expensed on a straight-line basis over the period during which the employee is required to provide service in exchange for the award (generally the vesting period).

The Company estimates the fair value of its stock-based awards using the Black-Scholes option-pricing model, which requires the input of assumptions. The assumptions are as follows:

•

Expected term. The expected term of stock options represents the period that the stock options are expected to remain outstanding and is based on vesting terms, exercise term and contractual lives of the options. The expected term of the ESPP shares is equal to the six-month look-back period.

•

Expected volatility. The expected stock price volatility for the Company’s stock options was derived from the average historical volatilities of the Company’s stock price and the stock price of several comparable publicly traded companies within the biotechnology and pharmaceutical industry. The Company will continue to apply this process until a sufficient amount of historical information on the Company’s own stock price becomes available. Volatility for ESPP shares is equal to the Company’s historical volatility over the six-month offering period.

•

Risk-free interest rate. The risk-free interest rate is based on the U.S. Treasury yield with a maturity equal to the expected term of the stock options in effect at the time of grant.

•

Dividend yield. The expected dividend is assumed to be zero as the Company has never paid dividends and has no current plan to pay any dividends on its common stock.

Leases

The Company determines if an arrangement is or contains a lease at inception. Operating leases are recorded as operating lease right-of-use (“ROU”) assets and operating lease liabilities in the Company’s balance sheet. ROU assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent its obligation to make lease payments arising from the lease. Operating lease ROU assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. The Company uses an implicit rate when readily available, or its incremental borrowing rate based on the information available at lease commencement date in determining the present value of lease payments. The operating lease ROU assets also include any lease prepayments made and reduced by lease incentives. The Company’s lease terms may include options to extend the lease when it is reasonably certain that such option will be exercised. Lease expenses are recognized on a straight-line basis over the lease term. The Company elected the short-term lease recognition exemption. The Company’s operating lease arrangement includes lease and non-lease components which are generally accounted for separately.

Adopted Accounting Pronouncements

Financial Instruments - Credit Losses

In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The new standard changes the impairment model for most financial assets and certain other instruments. Under the new standard, entities holding financial assets and net investment in leases that are not accounted for at fair value through net income are to be presented at the net amount expected to be collected. An allowance for credit losses will be a valuation account that will be deducted from the amortized cost basis of the financial asset to present the net carrying value at the amount expected to be collected on the financial asset. This new standard also requires that credit losses related to available-for-sale debt securities be recorded as an allowance through net income rather than reducing the carrying amount under the previous other-than-temporary-impairment model. The Company adopted this standard on January 1, 2020 using a modified retrospective approach and there was no transition adjustment recorded to the Company’s beginning accumulated deficit as of January 1, 2020 as there was no incremental impairment loss needed to be recognized upon the adoption of this ASU.

Simplification of the Test for Goodwill Impairment

In January 2017, the FASB issued ASU No. 2017-04, Intangibles-Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment. The new standard simplifies the measurement of goodwill by eliminating the Step 2 impairment test. Step 2 measures a goodwill impairment loss by comparing the implied fair value of a reporting unit's goodwill with the carrying amount of that goodwill. The new guidance requires an entity to compare the fair value of a reporting unit with its carrying amount and recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit's fair value. Additionally, an entity should consider income tax effects from any tax-deductible goodwill on the carrying amount of the reporting unit when measuring the goodwill impairment loss, if applicable. The Company adopted this standard on January 1, 2020 and there was no material impact on its financial statement.

Fair Value Measurement Disclosure Requirements Modification

In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820). The amendments in this ASU modify the disclosure requirements on fair value measurements in Topic 820, Fair Value Measurement. Various disclosure requirements have been removed, including the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy, the policy for timing of transfers between levels, the valuation processes for Level 3 fair value measurements held at the end of the reporting period. The ASU also modified various disclosure requirements and added some disclosure requirements for Level 3 fair value measurements. The amendments in this ASU were effective for the Company on January 1, 2020 and there was no material impact on its financial statements upon adoption of this ASU.

Internal Use Software Guidance for Cloud Computing Arrangement

In August 2018, the FASB issued ASU No. 2018-15, Intangibles-Goodwill and Other- Internal-Use Software (Subtopic 350-40). The amendments in this ASU on the accounting for implementation, setup and other upfront costs (collectively “implementation costs”) apply to entities that are a customer in a hosting arrangement. The amendments under this ASU align the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. Accordingly, the amendments in this ASU require an entity in a hosting arrangement that is a service contract to follow the guidance in Subtopic 350-40 to determine which implementation costs to expense. They also require an entity to expense the capitalized implementation costs of a hosting arrangement that is a service contract over the term of the hosting arrangement. The Company adopted this standard on January 1, 2020 and there was no material impact on its financial statement upon adoption of this ASU.

Collaborative Arrangements and Revenue Recognition

In November 2018, the FASB issued ASU No. 2018-18, Collaborative Arrangements (Topic 808): Clarifying the interaction between Topic 808 and Topic 606. The amendments in this ASU targeted improvements to generally accepted accounting principles for collaborative arrangements by clarifying that certain transactions between collaborative arrangement participants should be accounted for as revenue under Topic 606 when the collaborative arrangement participant is a customer in the context of a unit of account. In addition, unit-of-account guidance in Topic 808 was aligned with the guidance in Topic 606 (that is, a distinct good or service) when an entity is assessing whether the collaborative arrangement or a part of the arrangement is within the scope of Topic 606. The ASU was effective for the Company on January 1, 2020, and there was no material impact on its financial statements upon adoption of this ASU.

Share-Based Payment to Customer

In November 2019, the FASB issued ASU 2019-08, Compensation - Stock Compensation (Topic 718) and Revenue from Contracts with Customers (Topic 606): Codification Improvements – Share-Based Consideration Payable to a Customer. The amendments in this ASU require that an entity measure and classify share-based payment awards granted to a customer by applying the guidance in Topic 718. Under ASC 606, these awards are considered a reduction of the transaction price, unless the awards are payment for a distinct good or service received from the customer and should be recorded as a reduction of the transaction price. However, the ASU requires these awards to be measured on the basis of the grant-date fair value of the share-based payment award in accordance with Topic 718 and should be recognized at the later of when the award is promised and when the entity recognizes revenue for the transfer of the related goods or services in accordance with ASC 606. The ASU is effective for the Company on January 1, 2020, and there was no material impact on its financial statements upon adoption of this ASU.

Recent Accounting Pronouncements

In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. The amendments in this ASU simplify the accounting for income taxes by removing certain exceptions to the general principles of ASC 740 in order to reduce cost and complexity of its application. The ASU removes the exception related to the incremental approach for intraperiod tax allocation as well as two exceptions related to accounting for outside basis differences of equity method investments and foreign subsidiaries. The ASU also amends the scope of ASC 740 related to a franchise tax (or similar tax) that is partially based on income; clarifies when a step-up in the tax basis of goodwill should be considered part of the business combination in which the book goodwill was originally recognized and when it should be considered a separate transaction; specifies that an entity is not required to allocate income tax expense to a legal entity that is both not subject to tax and disregarded by the taxing authority; and clarifies that all tax effects, both deferred and current, should be accounted for in the interim period that includes the enactment date. The ASU is effective for the Company on January 1, 2021, and interim periods within those fiscal years. The Company does not expect the adoption of this ASU will have a material impact on its financial statements.

Fair Value Measurements and Short-Term Investments

9 Months Ended

Sep. 30, 2020

Fair Value Disclosures [Abstract]

Fair Value Measurements and Short-Term Investments

4. Fair Value Measurements and Short-Term Investments

In accordance with Accounting Standards Codification (“ASC”) 820-10, Fair Value Measurements and Disclosures, the Company determines the fair value of financial and non-financial assets and liabilities using the fair value hierarchy, which establishes three levels of inputs that may be used to measure fair value, as follows:

•

Level I: Inputs which include quoted prices in active markets for identical assets and liabilities.

•

Level II: Inputs other than Level I that are observable, either directly or indirectly, such as quoted prices 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 III: Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.

The carrying amounts of the Company’s financial instruments, including restricted cash, accounts receivable, accounts payable and accrued liabilities approximate fair value due to their relatively short maturities. The Company’s financial instruments consist of Level I assets which consist primarily of highly liquid money market funds, some of which are included in restricted cash, and U.S. government bonds that are included in short-term investments.

The following tables set forth the fair value of the Company’s short-term investments subject to fair value measurements on a recurring basis and the level of inputs used in such measurements:

		September 30, 2020
	Valuation Hierarchy	Amortized Cost		Allowance for Credit Losses		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses		Aggregate Fair Value
		(in thousands)
Assets
Money market funds	Level I	$	150,950	$	—	$	—	$	—	$	150,950
Restricted cash (money market funds)	Level I		917		—		—		—		917
U.S. Government bonds	Level I		144,260		—		6		—		144,266
Total		$	296,127	$	—	$	6	$	—	$	296,133

		December 31, 2019
	Valuation Hierarchy	Amortized Cost		Allowance for Credit Losses		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses		Aggregate Fair Value
		(in thousands)
Assets
Money market funds	Level I	$	170,757	$	—	$	—	$	—	$	170,757
Restricted cash (money market funds)	Level I		917		—		—		—		917
U.S. Government bonds	Level I		107,610		—		110		—		107,720
Total		$	279,284	$	—	$	110	$	—	$	279,394

As of September 30, 2020, no securities have contractual maturities of greater than 12 months.

The unrealized gains on the Company’s investment in US Government bonds were caused by interest rate decreases. The contractual terms of those investments are less than a year and do not permit the issuer to settle the securities at a price less than the amortized cost bases of the investments if held to maturity. The Company does not intend to sell the investments and it is not more likely than not that the Company will be required to sell the investments before recovery of their amortized cost bases.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Research and Collaboration Agreements

9 Months Ended

Sep. 30, 2020

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Research and Collaboration Agreements

6. Research and Collaboration Agreements

The following table summarizes the revenue by collaboration partners:

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2020		2019		2020		2019
	(in thousands)				(in thousands)
AbbVie	$	4,209	$	1,652	$	35,624	$	5,983
Amgen		1,633		1,648		7,007		2,905
Astellas		4,543		-		9,133		-
Bristol Myers Squibb		7,403		7,412		32,225		40,322
Total revenue	$	17,788	$	10,712	$	83,989	$	49,210

AbbVie Ireland Unlimited Company

In April 2016, the Company and AbbVie entered into two agreements, a CD71 Co-Development and Licensing Agreement (the “CD71 Agreement”) and a Discovery Collaboration and Licensing Agreement (as amended and restated in June 2019, the “Discovery Agreement” and together with the CD71 Agreement the “AbbVie Agreements”). Under the terms of the CD71 Agreement, the Company and AbbVie will co-develop a Probody Drug Conjugate (“PDC”) against CD71, with the Company responsible for pre-clinical and early clinical development. AbbVie will be responsible for later development and commercialization, with global late-stage development costs shared between the two companies. The Company will assume 35% of the net profits or net losses related to later development unless it opts-out. If the Company opts-out from participation of co-development of the CD71 PDC, which includes CX-2029, AbbVie will have sole right and responsibility for the further development, manufacturing and commercialization of such CD71 PDC.

Under the CD71 Agreement, the Company received an upfront payment of $20.0 million in April 2016, and is eligible to receive up to $470.0 million in development, regulatory and commercial milestone payments, a 35% profit split on U.S. sales, and royalties on ex-U.S. sales in the high teens to low twenties percentage if the Company participates in the co-development of the CD71 PDC subject to a reversion to a royalty on U.S. sales, and reduction in royalties on ex-U.S. sales, if the Company opts-out from the co-development of the CD71 PDC. The Company’s share of later stage co-development costs for each CD71 PDC are capped, provided that AbbVie may offset the Company’s co-development cost above the capped amounts from future payments such as milestone payments and royalties. In July 2017, the Company received a milestone payment of $14.0 million (net of payment of an associated sublicense fee of $1.0 million to SGEN under the Seattle Genetics Agreement) from AbbVie for achieving certain milestones required to be met to begin GLP toxicology studies under the CD71 Agreement. In May 2018, the United States Food and Drug Administration (“FDA”) cleared the IND application for CX-2029. As a result, the Company achieved the IND success criteria under the CD71 Agreement and received a $21.0 million milestone payment (net of the payment of an associated sublicense fee of $4.0 million to SGEN). In March 2020, the Company earned a $40.0 million milestone payment for satisfying the CD71 dose escalation success criteria under the CD71 Agreement.

Under the terms of the Discovery Agreement, AbbVie receives exclusive worldwide rights to develop and commercialize PDCs against up to two targets, one of which was selected in March 2017. The Company shall perform research services to discover the Probody therapeutics and create PDCs for the nominated collaboration targets. From that point, AbbVie shall have sole right and responsibility for development and commercialization of products comprising or containing such PDCs (“Discovery Licensed Products”).

Under the Discovery Agreement, the Company received an upfront payment of $10.0 million in April 2016 and subsequently earned an additional $10.0 million milestone payment triggered by selection of the second target by AbbVie in June 2019. The Company is also eligible to receive up to $275.0 million in development, regulatory and commercial milestone payments and royalties in the high single to low teens percentage from commercial sales of any resulting PDCs. The second target was selected under the Discovery Agreement that allows AbbVie to select a target for developing a PDC or a Probody.

The Company has determined that the AbbVie Agreements should be combined and evaluated as a single arrangement in determining revenue recognition, because both agreements were concurrently negotiated and executed.

The Company identified the following performance obligations at the inception of the AbbVie Agreements:

(1)

the research, development and commercialization license for CD71 Probody therapeutic,

(2)

the research services related to CD71 Probody therapeutic,

(3)

the obligation to participate in the CD71 Agreement joint research committee,

(4)

the research services related to the first discovery target

(5)

the research, development and commercialization license for the first discovery target, and

(6)

the obligation to participate in the Discovery Agreement joint research committee.

The Company concluded that AbbVie’s option for the second discovery target was not a material right and was therefore not a performance obligation at the inception of the AbbVie Agreements. However, it was subsequently included in the total transaction price in June 2019 as a performance obligation upon AbbVie’s selection of such second target as further discussed below.

The Company determined that the research, development and commercialization licenses for CD71 and discovery targets are not distinct from the Company’s respective research services and expertise. The Company considered factors such as novelty of the Probody therapeutic and PDC technology and lack of other parties’ expertise in this space, the Company’s rights to technology relating to a proprietary platform to enable the Probody therapeutic development and AbbVie’s contractual obligation to use the Company’s research services. The Company determined that the CD71 Agreement research, development and commercialization license, related research service and participation in the joint research committee were a combined performance obligation and were distinct from the Discovery Agreement research, development and commercialization license, related research service and participation in the joint research committee. Therefore, the Company concluded that there are two distinct performance obligations:

(1)

the CD71 Agreement performance obligation consisting of the CD71 Agreement research, development and commercialization license, related research service and participation in the joint research committee, and

(2)

the Discovery Agreement performance obligation consisting of the Discovery Agreement research, development and commercialization license, related research service and participation in the joint research committee.

The total transaction price for the Discovery Agreement and CD71 Agreement, collectively, upon adoption of ASC 606 on January 1, 2018 of $39.8 million consists of $30.0 million in upfront payments, and a $14.0 million milestone payment received under the CD71 Agreement (net of the payment of an associated sublicense fee of $1.0 million to SGEN), less $4.2 million of estimated sublicense fees. The upfront payments under the AbbVie Agreements are allocated between the two performance obligations based on the estimated relative standalone selling prices. The $30.0 million of upfront payments is allocated $20.0 million to the CD71 Agreement, with the remaining $10.0 million allocated to the Discovery Agreement. The $14.0 million milestone payment received (net of the payment of an associated sublicense fee of $1.0 million to SGEN) and the estimated sublicense fees of $4.2 million are allocated to the CD71 Agreement performance obligation as they are directly related to the development of the CX-2029.

Therefore, of the $39.8 million total initial transaction price discussed above, the Company allocated $29.8 million to the CD71 Agreement performance obligation and recognized revenue using a cost-based input measure, the common measure of progress for the performance obligation. In applying the cost-based input method, revenue is recognized based on actual full-time employee (“FTE”) hours incurred as a percentage of total estimated FTE hours for completing its combined performance obligation over the estimated service period. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. During 2019, as a result of ongoing dose escalation in the continued development program, there has been a change in estimates of the research service period as well as an increase in the projected FTE hours-to-completion. The research service period for the CD71 Agreement performance obligation was extended from April 2021 to March 2022 in 2019. During the second quarter of 2020, the Company further increased the projected FTE hours-to-completion and extended the research service period for the CD71 Agreement performance obligation from March 2022 to September 2022 in response to the reduced rate of operation as impacted by the COVID-19 pandemic.

The remaining $10.0 million of the total initial transaction price of $39.8 million allocated to the Discovery Agreement performance obligation represents an obligation to continuously make the Company’s Probody therapeutic technology platform available to AbbVie. The $10.0 million is recognized on a straight-line basis over a five-year estimated research service period through April 2021 using the time-elapsed input method as the common measure of progress over the entire performance obligation.

In May 2018, the Company earned a $21.0 million milestone payment (net of the payment of an associated sublicense fee of $4.0 million to SGEN) under the CD71 Agreement. The $21.0 million milestone payment was included as part of the transaction price in May 2018 and a revenue adjustment of $9.9 million was recognized in the second quarter of 2018 reflecting the percentage completed to-date on the project related to this milestone.

In June 2019, the Company earned a $10.0 million milestone payment for the second target selected by AbbVie under the Discovery Agreement. It is recognized also using the time-elapse measure of progress of the related obligation and straight line over the estimated research service period of five years through June 2024.

The $40.0 million milestone payment earned in March 2020 for satisfying the CD71 dose escalation success criteria under the CD71 Agreement was included as part of the transaction price as it was unconstrained during the first quarter of 2020 and $26.6 million was recognized as revenue related to this milestone, which reflected the percentage completed to-date on the project in March 2020. The remaining $13.4 million will be recognized over the remaining research service period through September 2022.

The Company is obligated to make sublicense payments under the license agreement with the Regents of the University of California, acting through its Santa Barbara campus (“UCSB”), as amended, equal to up to 7.5% of certain upfront and milestone payments owed to or received by the Company. As of both September 30, 2020 and December 31, 2019, there was no sublicense fee payable to UCSB.

The Company determined that the remaining potential milestone payments of both agreements are probable of significant revenue reversal as their achievement is highly dependent on factors outside the Company’s control. Therefore, these payments continued to be fully constrained and were not included in the transaction price as of September 30, 2020.

The Company recognized revenue of $4.2 million and $1.7 million for the three months ended September 30, 2020 and 2019, respectively, and $35.6 million and $6.0 million for the nine months ended September 30, 2020 and 2019, respectively, related to the AbbVie Agreements. As of September 30, 2020 and December 31, 2019, deferred revenue related to the CD71 Agreement performance obligation was $27.4 million and $20.0 million, respectively, and deferred revenue related to the Discovery Agreement performance obligation was $8.7 million and $11.6 million, respectively. As of both September 30, 2020 and December 31, 2019, no amount was due from AbbVie under the AbbVie Agreements.

Amgen, Inc.

On September 29, 2017, the Company and Amgen, Inc. (“Amgen”) entered into a Collaboration and License Agreement (the “Amgen Agreement”). Pursuant to the Amgen Agreement, the Company received an upfront payment of $40.0 million in October 2017. Concurrent with the entry into the Amgen Agreement, the Company and Amgen entered into a Share Purchase Agreement (the “Purchase Agreement”) pursuant to which Amgen purchased 1,156,069 shares of the Company’s common stock at a price of $17.30 per share (calculated based on a 20-day volume-weighted average price), for total proceeds of $20.0 million, which the Company received on October 6, 2017, the closing date of the transaction. The Company estimated a premium on the stock sold to Amgen of $0.5 million, which takes into account a discount due to the lack of marketability resulting from the six-month lockup period.

Under the terms of the Amgen Agreement, the Company and Amgen will co-develop a Probody T-cell engaging bi-specific therapeutic targeting epidermal growth factor receptor (the “EGFR Products”). The Company is responsible for early-stage development of EGFR Products and all related costs up to certain pre-set costs and certain limits based on clinical trial size. Amgen will be responsible for late-stage development, commercialization, and all related costs of EGFR Products. Following early-stage development, the Company will have the right to elect to participate financially in the global co-development of EGFR Products with Amgen, during which the Company would bear certain of the worldwide development costs for EGFR Products and Amgen would bear the rest of such costs (the “EGFR Co-Development Option”). If the Company exercises its EGFR Co-Development Option, the Company will share in somewhat less than 50% of the profit and losses from sales of such EGFR Products in the U.S., subject to certain caps, offsets, and deferrals. If the Company chooses not to exercise its EGFR Co-Development Option, the Company will not bear any costs of later stage development. The Company is eligible to receive up to $455.0 million in development, regulatory, and commercial milestone payments for EGFR Products, and royalties in the low-double-digit to mid-teen percentage of worldwide commercial sales, provided that if the Company exercises its EGFR Co-Development option, it shall receive a profit and loss split of sales in the United States and royalties in the low-double-digit to mid-teen percentage of commercial sales outside of the United States.

Amgen also has the right to select a total of up to three targets, including the two additional targets discussed below. The Company and Amgen collaborate in the research and development of Probody T-cell engaging bi-specifics products directed against such targets. Amgen has selected one such target (the “Amgen Other Product”). If Amgen exercises its option within the specified period of time, it can select two such additional targets (the “Amgen Option Products” and, together with the Amgen Other Product, the “Amgen Products”). Except with respect to preclinical activities to be conducted by CytomX, Amgen will be responsible, at its expense, for the development, manufacture, and commercialization of all Amgen Products. If Amgen exercises all of its options and advances all three of the Amgen Products, CytomX is eligible to receive up to $950.0 million in upfront, development, regulatory, and commercial milestones and tiered high single-digit to low-teen percentage royalties. The Company concluded that, at the inception of the agreement, Amgen’s option to select the two additional targets is not a material right and does not represent a performance obligation of the agreement.

At the initiation of the collaboration, CytomX had the option to select, from programs specified in the Amgen Agreement, an existing pre-clinical stage T-cell engaging bispecific product from the Amgen pre-clinical pipeline. In March 2018, CytomX selected the program. CytomX is responsible, at its expense, for converting this program to a Probody T-cell engaging bispecific product, and thereafter, will be responsible for development, manufacturing, and commercialization of the product (“CytomX Product”). Amgen is eligible to receive up to $203.0 million in development, regulatory, and commercial milestone payments for the CytomX Product, and tiered mid-single digit to low double-digit percentage royalties.

The Company considered the criteria for combining contracts in ASC 606 and determined that the Amgen Agreement and the Purchase Agreement should be combined into one contract. The Company accounted for the Amgen Agreement based on the fair values of the assets and services exchanged. The Company identified the following performance obligations at the inception of the Amgen Agreement:

(1)

the research, development and commercialization license,

(2)

the research and development services for the EGFR Products and the Amgen Other Product, and

(3)

the obligation to participate in the joint steering committee (“JSC”) and the joint research committee (“JRC”).

The Company determined that research, development and commercialization license and the participation in the JSC and JRC are not distinct from the research and development services and therefore those performance obligations were combined into one combined performance obligation. The Amgen Other Products are accounted for as a separate performance obligation from the EGFR Products as the nature of the services being performed is not the same and the value that Amgen can derive from one program is not dependent on the success of the other. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition.

Concurrent with the execution of the Amgen Agreement, the Company entered into a sublicense agreement whereby the Company granted Amgen a sublicense of its rights to one patent family that it co-owns with UCSB, that is exclusively licensed to the Company under the UCSB Agreement covering Probody antibodies and other pro-proteins in the fields of therapeutics, in vivo diagnostics and prophylactics. This sublicense was incremental to the patents, patent applications and know-how covering T-cell engaging bispecific Probody molecules that were developed and owned by the Company and licensed to Amgen. Under the UCSB Agreement, as amended, the Company is obligated to make a sublicense payment to UCSB equal to up to 7.5% of certain upfront and milestone payments owed to or received by the Company. As of both September 30, 2020 and December 31, 2019, the Company recorded no sublicense fee payable to UCSB.

The total transaction price of $51.2 million, consisting of the $40.0 million upfront payment, an estimated fair value of $10.7 million for the CytomX Product and $0.5 million of premium on the sale of the Company’s common stock, was allocated between the two performance obligations based on the relative standalone selling price of each performance obligation. To determine the standalone selling price, the Company used the discounted cash flow method by calculating risk-adjusted net present values of estimated cash flows. The Company determined that the remaining potential milestone payments were probable of significant revenue reversal as their achievement was highly dependent on factors outside the Company’s control. As a result, these payments were fully constrained and were not included in the transaction price as of January 1, 2018, the adoption date of ASC 606.

Of the $51.2 million total transaction price, the Company allocated $46.4 million to the EGFR Products performance obligation and $4.8 million to the Amgen Other Product performance obligations. The transaction price of the EGFR Product performance obligation was recognized using a cost-based input measure. In applying the cost-based input method of revenue recognition, the Company uses actual FTE hours incurred relative to estimated total FTE hours expected to be incurred for the combined performance obligation over the research service period. At the end of the second quarter of 2019, the Company determined that it will undertake additional

testing and assessment of the molecules being evaluated under the EGFR project. As a result, the estimated FTE hours-to-completion and research service period were increased to eight years. In the second quarter of 2020, the Company completed the clinical candidate characterization phase and has moved into the IND-enabling phase earlier than planned. As a result, the estimated FTE hours-to-completion and research service period were decreased from eight to seven years.

The $4.8 million transaction price allocated to the Amgen Other Product performance obligation represents an obligation to continuously make the Probody therapeutic technology platform available to Amgen, which is recognized over the common measure of progress for the entire performance obligation over the estimated research service period of six years.

The Company recognized revenue of $1.6 million for each of the three-month periods ended September 30, 2020 and 2019, and $7.0 million and $2.9 million for the nine months ended September 30, 2020 and 2019, respectively, related to the Amgen Agreement. As of September 30, 2020 and December 31, 2019, deferred revenue related to the EGFR Products performance obligation was $31.2 million and $37.6 million, respectively. As of September 30, 2020 and December 31, 2019, deferred revenue related to the Amgen Other Products performance obligation was $2.4 million and $3.0 million, respectively. As of both September 30, 2020 and December 31, 2019, no amount was due from Amgen under the Amgen Agreement.

Astellas Pharma Inc.

The Company and Astellas Pharma, Inc. (“Astellas”) entered into a Collaboration and License Agreement (the “Astellas Agreement”) on March 23, 2020, the effective date, to collaborate on preclinical research activities to discover and develop certain antibody compounds for the treatment of cancer using the Company’s Probody therapeutic technology.

Under the terms of the Astellas Agreement, the Company granted Astellas an exclusive, worldwide, rights to develop and commercialize Probody therapeutics for up to four collaboration targets including one initial target and three additional targets (“Additional Targets”). In addition, Astellas has the right to expand the number of Additional Targets from three up to five (the “Expansion Option”) before the third anniversary of the effective date. Furthermore, for a specified number of targets, at a pre-specified time prior to the initiation of the first pivotal study of a product against such target, the Company may elect to participate in certain development costs and share in the profits generated in the United States with respect to such product (“Cost Share Option”). The Cost Share Option, if exercised, will also provide the option for the Company to co-commercialize such product in the United States. The Company does not consider the Cost Share Option as a performance obligation at the inception of the agreement as the participation is at the Company’s discretion.

Pursuant to the Astellas Agreement, the consideration from Astellas is comprised of an upfront fee of $80.0 million and contingent payments for development, regulatory and sales milestones of up to an aggregate of approximately $1.6 billion. If Astellas exercises its Expansion Option for the two Additional Targets, the Company would be eligible to receive additional upfront and milestone payments aggregating to approximately $0.9 billion. The Company is also entitled to tiered royalties from high-single digit to mid-teen percentage royalties from potential future sales. Astellas is responsible for all preclinical research costs incurred by either party as set forth in the preclinical research plan and the Company will receive research and development service fees based on a prescribed FTE rate.

The Company identified the following performance obligations at the inception of the Astellas Agreement:

(1)

the exclusive research, development and commercialization license;

(2)

the research and development services; and

(3)

the obligation to participate in the joint research committee.

The Company determined that the license, the research services and expertise related to the development of the product candidates should be combined with the research services and participation in the joint research committee as one combined performance obligation. The Company concluded, that at the inception of the agreement, Astellas’ Expansion Option for two Additional Targets were not material rights and therefore not considered performance obligations. As such, each option will be accounted for as a separate arrangement upon exercise.

The initial transaction price of $90.0 million consists of the upfront fee of $80.0 million and research and development service fees of $10.0 million. The Company determined that the potential development and regulatory milestone payments were probable of significant revenue reversal as their achievement was highly dependent on factors outside the Company’s control. Therefore, the potential development and regulatory milestone payments were fully constrained and were not included in the initial transaction price and continued to be fully constrained as of September 30, 2020. The Company will re-evaluate the transaction price at each reporting date or as uncertain events are resolved or other changes in circumstances occur.

The upfront fee of $80.0 million for the combined obligation to continuously make the Probody therapeutic technology platform available to Astellas is recognized on a straight-line basis for the entire performance obligation over the estimated research service period of five years, which ends in March 2025. The research and development service fees, estimated to be $10.0 million, will be recognized when services are provided based on the prescribed FTE rate.

Under the UCSB Agreement, as amended, the Company is obligated to make a sublicense payment to UCSB equal to up to 7.5% of certain upfront and milestone payments owed to or received by the Company. The Company recorded a liability upon entering into the Astellas Agreement in the first quarter of 2020 of $6.0 million, representing 7.5% of the $80.0 million upfront payment, as a sublicense fee payable to UCSB, which was fully paid in the second quarter of 2020.

The Company recognized revenue of $4.5 million and $9.1 million for the three and nine months ended September 30, 2020, which included the research and development service fee of $0.5 million and $0.7 million for the three and nine months ended September 30, 2020. As of September 30, 2020, deferred revenue relating to the Astellas Agreement was $71.6 million. The amount due from Astellas under the Astellas Agreement was $0.5 million as of September 30, 2020.

Bristol Myers Squibb Company

On May 23, 2014, the Company and Bristol Myers Squibb Company (“Bristol Myers Squibb”) entered into a Collaboration and License Agreement (the “BMS Agreement”) to discover and develop compounds for use in human therapeutics aimed at multiple immuno-oncology targets using the Company’s Probody therapeutic technology. The effective date of the BMS Agreement was July 7, 2014.

Under the terms of the BMS Agreement, the Company granted Bristol Myers Squibb exclusive worldwide rights to develop and commercialize Probody therapeutics for up to four oncology targets. Bristol Myers Squibb had additional rights to substitute up to two collaboration targets within three years of the effective date of the BMS Agreement. These rights expired in May 2017. Each collaboration target had a two-year research term and the two additional targets had to be nominated by Bristol Myers Squibb within five years of the effective date of the BMS Agreement. The research term for each collaboration target could be extended in one year increments up to three times.

Pursuant to the BMS Agreement, the financial consideration from Bristol Myers Squibb was comprised of an upfront payment of $50.0 million, and the Company was initially entitled to receive contingent payments of up to $25.0 million for additional targets and up to an aggregate of $1,192.0 million for development, regulatory and sales milestones. In addition, the Company is entitled to royalty payments in the mid-single digits to low double-digit percentages from potential future sales. The Company also receives research and development service fees based on a prescribed FTE rate that is capped.

The Company identified the following performance obligations at the inception of the BMS Agreement:

(1)

the exclusive research, development and commercialization license;

(2)

the research and development services; and

(3)

the obligation to participate in the joint research committee.

The Company determined that the license, the Company’s research services and expertise related to the development of the product candidates should be combined with the research services and participation in the joint research committee as one combined performance obligation. The Company concluded that, at the inception of the agreement, Bristol Myers Squibb’s options for the third and fourth targets were not material rights and not performance obligations. As such, each option was accounted for as a separate arrangement upon exercise. Additionally, the Company considered whether the services performed for each target should be considered as separate performance obligations and concluded that all targets should be accounted for as one combined performance obligation.

The Company received an upfront payment of $50.0 million from Bristol Myers Squibb in July 2014. In January and December 2016, Bristol Myers Squibb selected the third and fourth targets, respectively, and paid the Company $10.0 million and $15.0 million, respectively, pursuant to the terms of the BMS Agreement. In December 2016, Bristol Myers Squibb selected a clinical candidate pursuant to the BMS Agreement, which triggered a $2.0 million pre-clinical milestone payment to the Company. In November 2017, the Company recognized a $10.0 million milestone payment from Bristol Myers Squibb upon approval of the investigational new drug application for the CTLA-4-directed Probody therapeutic.

On March 17, 2017, the Company and Bristol Myers Squibb entered into Amendment Number 1 to Extend Collaboration and License Agreement (the “BMS Amendment”). The BMS Amendment grants Bristol Myers Squibb exclusive worldwide rights to develop and commercialize Probody therapeutics for up to eight additional targets. The effective date of the BMS Amendment was April 25, 2017 (“Amendment Effective Date”). Under the terms of the BMS Amendment, the Company continues to have obligations to Bristol Myers Squibb to discover and conduct preclinical development of Probody therapeutics against any targets they choose to select during the research period under the terms of the BMS Amendment.

Pursuant to the BMS Amendment, the financial consideration from Bristol Myers Squibb is comprised of an upfront payment of $200.0 million and the Company was initially eligible to receive contingent payments for development, regulatory and sales milestones of up to an aggregate of $3,586.0 million for the eight targets. The Company is also entitled to tiered mid-single to low double-digit percentage royalties from potential future sales. The BMS Amendment does not change the term of the Bristol Myers Squibb’s royalty obligation under the BMS Agreement. Bristol Myers Squibb’s royalty obligation continues on a licensed-product by licensed-product basis until the later of (i) the expiration of the last claim of the licensed patents covering the licensed products in the country, (ii) the twelfth anniversary of the first commercial sale of a licensed product in a country, or (iii) the expiration of any applicable regulatory, pediatric, orphan drug or data exclusivity with respect to such product.

The initial transaction price for the BMS Agreement and the BMS Amendment, collectively, was $272.8 million consisting of the upfront fees of $250.0 million, research and development service fees of $10.8 million and milestone payments received to date of $12.0 million. The Company determined that the remaining potential milestone payments were probable of significant revenue reversal as their achievement was highly dependent on factors outside the Company’s control. Therefore, these payments were fully constrained and were not included in the transaction price upon the adoption of ASC 606 on January 1, 2018. The BMS Agreement represents an obligation to continuously make the Probody therapeutic technology platform available to Bristol Myers Squibb. Therefore, the initial transaction price is recognized over the estimated research service period, which ends on April 25, 2025.

During the first quarter of 2019, Bristol Myers Squibb terminated pre-clinical activities on three of the first four collaboration targets selected under the original 2014 BMS Agreement. The first and second targets under the BMS Agreement were combined into a single performance obligation. The Company determined that termination of pre-clinical activities on the second target does not impact the Company’s continuing obligation to Bristol Myers Squibb for the first target, CTLA-4, as it is still being actively developed by Bristol Myers Squibb. Therefore, the Company concluded that it will continue to amortize the related deferred revenue over the original performance period. The Company has determined that upon the termination of pre-clinical activities on the third and the fourth collaboration targets selected by Bristol Myers Squibb in January and December of 2016, respectively, under the BMS Agreement, it has no further obligations and is no longer eligible to receive any further proceeds from milestones, royalties or research and development fees for such targets. As a result, the Company accelerated recognition of all of the related deferred revenue of the third and the fourth targets upon the effective date of termination and recognized $17.4 million in the first quarter of 2019. The Company continues to be obligated to perform research work under the BMS Amendment executed in March 2017.

In February 2020, Bristol Myers Squibb dosed the first patient in the Part 2 cohort expansion portion of its ongoing BMS-986249 clinical study for the CTLA-4 program, which triggered a $10.0 million milestone payment to the Company pursuant to the terms of the BMS Agreement. The $10.0 million milestone payment was recognized as revenue in the first quarter of 2020. The Company reevaluated the remaining potential milestone payments and determined that significant revenue reversal was still probable as the achievement of such milestones was highly dependent on factors outside the Company’s control. As a result, these payments continued to be fully constrained and were not included in the transaction price on September 30, 2020.

The Company recognized revenue of $7.4 million for each of the three-month periods ended September 30, 2020 and 2019 and $32.2 million and $40.3 million for the nine months ended September 30, 2020 and 2019, respectively. As of September 30, 2020 and December 31, 2019, deferred revenue relating to the BMS Agreement was $135.7 million and $158.0 million, respectively. The amount due from Bristol Myers Squibb under the BMS Agreement was $0 and $13,000 as of September 30, 2020 and December 31, 2019, respectively.

ImmunoGen, Inc.

In January 2014, the Company and ImmunoGen, Inc. (“ImmunoGen”) entered into the Research Collaboration Agreement (the “ImmunoGen Research Agreement”). The ImmunoGen Research Agreement provided the Company with the right to use ImmunoGen’s Antibody Drug Conjugate (“ADC”) technology in combination with the Company’s Probody therapeutic technology to create a PDC directed at one specified target under a research license, and to subsequently obtain an exclusive, worldwide development and commercialization license to use ImmunoGen’s ADC technology to develop and commercialize such PDCs. The Company made no upfront cash payment in connection with the execution of the agreement. Instead, the Company provided ImmunoGen with the rights to CytomX’s Probody therapeutic technology to create PDCs directed at two targets under the ImmunoGen Research Agreement and to subsequently obtain exclusive, worldwide development and commercialization licenses to develop and commercialize such PDCs. In February 2016, the Company exercised its option to obtain a development and commercialization license for CX-2009 pursuant to the terms of the ImmunoGen Research Agreement (the “CX-2009 License”).

In February 2017, ImmunoGen exercised its first option to obtain a development and commercialization license for one of the two targets. Substitution rights for this first target selection program terminated in February 2017 and ImmunoGen discontinued the program in July 2017. The Company recognized the remaining deferred revenue related to the discontinued program upon the termination of the program. ImmunoGen exercised its second option to obtain a development and commercialization license pursuant to the ImmunoGen Research Agreement (the “ImmunoGen 2017 License”) for a target in December 2017. In December 2019, the parties entered into a license agreement (the “ImmunoGen 2019 License”) pursuant to which the ImmunoGen 2017 License was terminated and ImmunoGen granted a license for all of ImmunoGen’s rights under the ImmunoGen 2017 License to the Company. See Note 7. License Agreements, for more information.

Under the terms of the ImmunoGen Research Agreement, both the Company and ImmunoGen performed research activities on behalf of the other party for no monetary consideration through January 2018. In December 2017, the Company entered into the ImmunoGen 2017 License arrangement and extended the Company’s obligation to provide research services under the ImmunoGen Research Agreement to June 30, 2018. The estimated fair value of the consideration of $13.2 million for the performance obligation to ImmunoGen was recognized as revenue over the research period that ended on June 30, 2018. No further research services were provided by the Company after June 20, 2018 under the ImmunoGen 2017 License arrangement.

In February 2020, the Company initiated the first dosing of a patient in the CX-2009 Phase 2 clinical trial and triggered a $3.0 million milestone payment to ImmunoGen pursuant to the CX-2009 License which continued to remain in effect following the termination of the ImmunoGen 2017 License in December 2019. The Company recorded a $3.0 million charge to research and development expense in the first quarter of 2020, in connection with this milestone payment to ImmunoGen.

Contract Liabilities

The following table presents changes in the Company’s total contract liabilities during the nine months ended September 30, 2020:

	Balance at Beginning of Period		Additions		Deductions			Balance at End of Period
	(in thousands)
Contract liabilities:
Deferred revenue	$	230,239	$	120,000	$	(73,234	)	$	277,005

There were $120.0 million additions to deferred revenue during the nine months ended September 30, 2020. Of such amount, $40.0 million was related to the milestone payment triggered by AbbVie’s CD71 dose escalation success criteria which was achieved in March 2020, and an $80.0 million addition was related to the upfront fee payable under the Astellas Agreement entered into in March 2020. Deductions of $73.2 million related to revenue recognized included in the contract liability balance at the beginning of the period plus the revenue recognized related to the $120.0 million additions during the nine months ended September 30, 2020.

The Company expects that the $277.0 million of deferred revenue related to the following contracts as of September 30, 2020 will be recognized as revenue as set forth below. However, the timing of revenue recognition could differ from the estimates depending on facts and circumstances impacting the various contracts, including progress of research and development, resources assigned to the contracts by the Company or its collaboration partners, or other factors outside of the Company’s control.

•

The $27.4 million of deferred revenue related to the CD71 Agreement with AbbVie as of September 30, 2020 is expected to be recognized based on actual FTE effort and program progress until approximately September 2022.

•

The $1.2 million of deferred revenue related to the first target under the Discovery Agreement with AbbVie as of September 30, 2020 is expected to be recognized ratably until approximately April 2021.

•

The $7.5 million of deferred revenue related to the second target under the Discovery Agreement as of September 30, 2020 is expected to be recognized ratably until approximately June 2024.

•

The $31.2 million of deferred revenue related to the Amgen EGFR Products as of September 30, 2020 is expected to be recognized based on actual FTE effort and program progress until approximately September 2024.

•

The $2.4 million of deferred revenue related to the Amgen Other Products as of September 30, 2020 is expected to be recognized ratably until approximately September 2023.

•

The $71.6 million of deferred revenue related to the Astellas Agreement as of September 30, 2020 is expected to be recognized ratably until approximately March 2025.

•

The $135.7 million of deferred revenue related to the BMS Agreement as of September 30, 2020 is expected to be recognized ratably until approximately April 2025.

Leases

9 Months Ended

Sep. 30, 2020

Leases [Abstract]

Leases

10. Leases

Operating Lease

On December 10, 2015, the Company entered into a lease (the “2016 Lease”) with HCP Oyster Point III LLC (the “Landlord”) to -lease approximately 76,000 rentable square feet of office and laboratory space located in South San Francisco, California for the Company’s new corporate headquarters.

The term of the Lease commenced on October 1, 2016. The 2016 Lease has an initial term of ten years from the commencement date, and the Company has an option to extend the initial term for an additional five years at the then fair rental value as determined pursuant to the 2016 Lease.

The Lease provided for annual base rent of approximately $3.1 million in the first year of the lease term. The annual base rent for the second twelve months was approximately $4.3 million, which will increase on an annual basis beginning from the 25^th month to approximately $5.5 million for the tenth year of the lease. The Company utilized the full amount of the one-time improvement allowance of $12.6 million, of which $2.3 million is recoverable by the landlord through an increased rent which continues through the expiration of the initial lease term.

In addition, the Company obtained a standby letter of credit (the “Letter of Credit”) in an amount of approximately $0.9 million, which may be drawn by the Landlord to be applied for certain purposes upon the Company’s breach of any provisions under the 2016 Lease. The Company has recorded the $0.9 million Letter of Credit in restricted cash as non-current on its balance sheet at September 30, 2020 and December 31, 2019, respectively.

Rent expense is recognized on a straight-line basis over the term of the lease and accordingly the Company records the difference between cash rent payments and the recognition of rent expense against the operating lease ROU asset. Rent expense for both the three months ended September 30, 2020 and 2019 was $1.3 million. Rent expense for both the nine months ended September 30, 2020 and 2019 was $3.8 million.

Supplemental information related to leases are as follows:

	Three Months Ended				Nine Months Ended
	September 30, 2020		September 30, 2019		September 30, 2020			September 30, 2019
	(in thousands)				(in thousands)
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows from operating leases	$	1,239	$	1,205	$	3,717		$	3,615

					September 30, 2020			December 31, 2019
					(in thousands)
Supplemental balance sheet information related to leases:
Operating lease right-of-use assets					$	23,239		$	25,382
Current operating lease liabilities						3,096			2,810
Non-current operating lease liabilities						22,525			24,871
Total operating lease liabilities					$	25,621		$	27,681

Weighted-average remaining lease term (in years)
Operating lease						6.00			6.85
Weighted-average discount rate
Operating lease						8.25	%		8.25	%

	September 30, 2020
	(in thousands)
Maturity of operating lease liabilities
2020	$	1,274
2021		5,129
2022		5,273
2023		5,420
2024 and beyond		15,689
Total lease payments		32,785
Less imputed interest		(7,164	)
Present value of lease liabilities	$	25,621

Basis of Presentation and Summary of Significant Accounting Policies (Policies)

9 Months Ended

Sep. 30, 2020

Accounting Policies [Abstract]

Basis of Presentation

Unaudited Interim Financial Information

Use of Estimates

Cash and Cash Equivalents

The Company considers all highly liquid investments purchased with original maturities of three months or less at the date of purchase to be cash equivalents.

Restricted Cash

Restricted cash represents a standby letter of credit issued pursuant to an office lease entered in December 2015.

	September 30, 2020		December 31, 2019		September 30, 2019		December 31, 2018
	(in thousands)
Cash and cash equivalents	$	176,810	$	188,425	$	164,646	$	247,577
Restricted cash - non-current assets		917		917		917		917
Total	$	177,727	$	189,342	$	165,563	$	248,494

Short-term Investments

Comprehensive Loss

Revenue Recognition

Contract Balances

Research and Development Expenses

Stock-based Compensation

The Company estimates the fair value of its stock-based awards using the Black-Scholes option-pricing model, which requires the input of assumptions. The assumptions are as follows:

•

Risk-free interest rate. The risk-free interest rate is based on the U.S. Treasury yield with a maturity equal to the expected term of the stock options in effect at the time of grant.

•

Dividend yield. The expected dividend is assumed to be zero as the Company has never paid dividends and has no current plan to pay any dividends on its common stock.

Leases

Adopted Accounting Pronouncements and Recent Accounting Pronouncements

Adopted Accounting Pronouncements

Financial Instruments - Credit Losses

Simplification of the Test for Goodwill Impairment

Fair Value Measurement Disclosure Requirements Modification

Internal Use Software Guidance for Cloud Computing Arrangement

Collaborative Arrangements and Revenue Recognition

Share-Based Payment to Customer

Recent Accounting Pronouncements

Fair Value Measurements and Short-Term Investments (Tables)

9 Months Ended

Sep. 30, 2020

Fair Value Disclosures [Abstract]

Schedule of Short-Term Investments Subject to Fair Value Measurements on a Recurring Basis

The following tables set forth the fair value of the Company’s short-term investments subject to fair value measurements on a recurring basis and the level of inputs used in such measurements:

		September 30, 2020
	Valuation Hierarchy	Amortized Cost		Allowance for Credit Losses		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses		Aggregate Fair Value
		(in thousands)
Assets
Money market funds	Level I	$	150,950	$	—	$	—	$	—	$	150,950
Restricted cash (money market funds)	Level I		917		—		—		—		917
U.S. Government bonds	Level I		144,260		—		6		—		144,266
Total		$	296,127	$	—	$	6	$	—	$	296,133

		December 31, 2019
	Valuation Hierarchy	Amortized Cost		Allowance for Credit Losses		Gross Unrealized Holding Gains		Gross Unrealized Holding Losses		Aggregate Fair Value
		(in thousands)
Assets
Money market funds	Level I	$	170,757	$	—	$	—	$	—	$	170,757
Restricted cash (money market funds)	Level I		917		—		—		—		917
U.S. Government bonds	Level I		107,610		—		110		—		107,720
Total		$	279,284	$	—	$	110	$	—	$	279,394

Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2020

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Schedule of Activities Under Company's Stock Option Plans

Activities under the Company’s stock option plans for the nine months ended September 30, 2020 were as follows:

	Options Outstanding
	Number of Options			Weighted- Average Exercise Price Per Share
Balances at December 31, 2019		9,936,168		$	12.26
Options granted		3,762,244			7.23
Options exercised		(627,999	)		5.58
Option forfeited/expired		(1,688,953	)		13.94
Balances at September 30, 2020		11,381,460		$	10.72
Options exercisable at September 30, 2020		6,214,494		$	11.15

Total Stock-based Compensation Recognized

Total stock-based compensation recorded related to options granted to employees and non-employees and employee stock purchase plan was as follows:

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2020		2019		2020		2019
	(in thousands)
Stock-based compensation expense:
Research and development	$	1,735	$	1,948	$	5,317	$	7,241
General and administrative		2,106		2,395		6,050		7,748
Total stock-based compensation expense	$	3,841	$	4,343	$	11,367	$	14,989

Leases (Tables)

9 Months Ended

Sep. 30, 2020

Leases [Abstract]

Summary of Supplemental Information Related to Leases

Supplemental information related to leases are as follows:

	Three Months Ended				Nine Months Ended
	September 30, 2020		September 30, 2019		September 30, 2020			September 30, 2019
	(in thousands)				(in thousands)
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows from operating leases	$	1,239	$	1,205	$	3,717		$	3,615

					September 30, 2020			December 31, 2019
					(in thousands)
Supplemental balance sheet information related to leases:
Operating lease right-of-use assets					$	23,239		$	25,382
Current operating lease liabilities						3,096			2,810
Non-current operating lease liabilities						22,525			24,871
Total operating lease liabilities					$	25,621		$	27,681

Weighted-average remaining lease term (in years)
Operating lease						6.00			6.85
Weighted-average discount rate
Operating lease						8.25	%		8.25	%

Schedule of Maturity of Operating Lease Liabilities

	September 30, 2020
	(in thousands)
Maturity of operating lease liabilities
2020	$	1,274
2021		5,129
2022		5,273
2023		5,420
2024 and beyond		15,689
Total lease payments		32,785
Less imputed interest		(7,164	)
Present value of lease liabilities	$	25,621

Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Jan. 31, 2019	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Summary Of Significant Accounting Policies [Line Items]
Research and development expense		$ 24,049	$ 27,967	$ 90,929	$ 95,178
ASU 2016-13
Summary Of Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adoption date		Jan. 01, 2020		Jan. 01, 2020
Change in accounting principle, accounting standards update, adopted [true false]		true		true
ASU 2017-04
Summary Of Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adoption date		Jan. 01, 2020		Jan. 01, 2020
Change in accounting principle, accounting standards update, adopted [true false]		true		true
Change in accounting principle, accounting standards update, immaterial effect [true false]		true		true
ASU 2018-13
Summary Of Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adoption date		Jan. 01, 2020		Jan. 01, 2020
Change in accounting principle, accounting standards update, adopted [true false]		true		true
Change in accounting principle, accounting standards update, immaterial effect [true false]		true		true
ASU 2018-15
Summary Of Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adoption date		Jan. 01, 2020		Jan. 01, 2020
Change in accounting principle, accounting standards update, adopted [true false]		true		true
Change in accounting principle, accounting standards update, immaterial effect [true false]		true		true
ASU 2018-18
Summary Of Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adoption date		Jan. 01, 2020		Jan. 01, 2020
Change in accounting principle, accounting standards update, adopted [true false]		true		true
Change in accounting principle, accounting standards update, immaterial effect [true false]		true		true
ASU 2019-08
Summary Of Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adoption date		Jan. 01, 2020		Jan. 01, 2020
Change in accounting principle, accounting standards update, adopted [true false]		true		true
Change in accounting principle, accounting standards update, immaterial effect [true false]		true		true
ASU 2019-12
Summary Of Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adoption date		Jan. 01, 2021		Jan. 01, 2021
Change in accounting principle, accounting standards update, adopted [true false]		false		false
Change in accounting principle, accounting standards update, immaterial effect [true false]		false		false
Probody technology
Summary Of Significant Accounting Policies [Line Items]
Acquired, technology know-how	$ 5,000
Research and development expense				$ 5,000

Research and Collaboration Agreements - AbbVie Ireland Unlimited Company - Additional Information (Details)

1 Months Ended

3 Months Ended

9 Months Ended

Mar. 31, 2020

USD ($)

Jun. 30, 2019

USD ($)

May 31, 2018

USD ($)

Jul. 31, 2017

USD ($)

Apr. 30, 2016

USD ($)

Agreement

Target

AccountingUnit

Sep. 30, 2020

USD ($)

Sep. 30, 2019

USD ($)

Jun. 30, 2018

USD ($)

Sep. 30, 2020

USD ($)

Sep. 30, 2019

USD ($)

Dec. 31, 2019

USD ($)

Mar. 31, 2017

Target

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

$ 17,788,000

$ 10,712,000

$ 83,989,000

$ 49,210,000

us-gaap:LicenseAndServiceMember

$ 23,945,000

$ 30,051,000

^[1]

AbbVie Ireland Unlimited Company

277,005,000

230,239,000

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

$ 21,000,000.0

$ 4,200,000

$ 1,700,000

$ 9,900,000

$ 35,600,000

$ 6,000,000.0

AbbVie Ireland Unlimited Company | ASC 606

us-gaap:LicenseAndServiceMember

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

$ 30,000,000.0

14,000,000.0

Estimated sublicense fees

39,800,000

$ 4,200,000

Number of accounting units | AccountingUnit

AbbVie Ireland Unlimited Company | Collaborative Arrangement

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Number of collaboration agreements | Agreement

Percentage of net profits or net losses related to development costs

35.00%

AbbVie Ireland Unlimited Company | CD71 Agreement

$ 0

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

$ 20,000,000.0

$ 40,000,000.0

21,000,000.0

$ 14,000,000.0

Revenue recognition upon performance obligation

21,000,000.0

13,400,000

AbbVie Ireland Unlimited Company | CD71 Agreement | Transferred over Time

27,400,000

20,000,000.0

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

$ 26,600,000

AbbVie Ireland Unlimited Company | CD71 Agreement | ASC 606

us-gaap:LicenseAndServiceMember

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

20,000,000.0

Estimated sublicense fees

29,800,000

4,200,000

AbbVie Ireland Unlimited Company | CD71 Agreement | U.S

$ 14,000,000.0

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Profit split on U.S. sales and royalties on ex U.S. sales

35.00%

AbbVie Ireland Unlimited Company | CD71 Agreement | Maximum

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Contingent payments receivable upon achieving development, regulatory and commercial milestones

$ 470,000,000.0

AbbVie Ireland Unlimited Company | Seattle Genetics Agreement

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Sublicense fees paid

$ 4,000,000.0

$ 1,000,000.0

AbbVie Ireland Unlimited Company | Seattle Genetics Agreement | ASC 606

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Sublicense fees paid

1,000,000.0

AbbVie Ireland Unlimited Company | Discovery Agreement

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Number of targets selected | Target

10,000,000.0

Revenue recognition upon performance obligation

10,000,000.0

AbbVie Ireland Unlimited Company | Discovery Agreement | ASC 606

8,700,000

11,600,000

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

10,000,000.0

AbbVie Ireland Unlimited Company | Discovery Agreement | Second Target

$ 10,000,000.0

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Milestone payments received

$ 10,000,000.0

AbbVie Ireland Unlimited Company | Discovery Agreement | Second Target | ASC 606

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

$ 10,000,000.0

AbbVie Ireland Unlimited Company | Discovery Agreement | Maximum

5 years

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Number of targets | Target

AbbVie Ireland Unlimited Company | Discovery Agreement | Maximum | Development, Regulatory and Commercial Milestone Payments

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

AbbVie Ireland Unlimited Company | License Agreement | UC Regents

$ 275,000,000.0

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

7.50%

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

$ 0

[1]	The condensed balance sheet as of December 31, 2019 was derived from the audited financial statements included in the Company's Annual Report on Form 10-K for the year ended December 31, 2019.

Research and Collaboration Agreements - Amgen, Inc - Additional Information (Details)

1 Months Ended

3 Months Ended

9 Months Ended

Sep. 29, 2017

USD ($)

Target

Oct. 31, 2017

USD ($)

$ / shares

Sep. 30, 2020

USD ($)

Jun. 30, 2020

Sep. 30, 2019

USD ($)

Jun. 30, 2019

Sep. 30, 2020

USD ($)

Sep. 30, 2019

USD ($)

Dec. 31, 2019

USD ($)

$ 23,945,000

$ 30,051,000

^[1]

$ 17,788,000

$ 10,712,000

$ 83,989,000

$ 49,210,000

us-gaap:LicenseAndServiceMember

Amgen Inc | EGFR Products

$ 277,005,000

230,239,000

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Amgen Inc | Amgen Other Products

31,200,000

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaboration and License Agreement | Amgen Inc

2,400,000

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Common stock, shares issuable under agreement | shares

$ 40,000,000.0

1,156,069

Common stock, shares issuable under agreement, price per share | $ / shares

$ 17.30

Common stock, value of shares issued in connection with agreement

$ 20,000,000.0

Period used to calculate weighted average price per share

20 days

Lock-up period for share disposal

6 months

Estimated premium on the stock sold

$ 500,000

Number of targets selected | Target

Portion of transaction price allocated to premium on sale of common stock

$ 51,200,000

500,000

Estimated fair value of products

10,700,000

$ 1,600,000

$ 7,000,000.0

$ 2,900,000

us-gaap:LicenseAndServiceMember

Collaboration and License Agreement | Amgen Inc | Maximum

$ 0

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Contingent payments payable

203,000,000.0

Collaboration and License Agreement | Amgen Inc | EGFR Products

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

46,400,000

7 years

8 years

Collaboration and License Agreement | Amgen Inc | EGFR Products | Maximum

31,200,000

37,600,000

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Percentage share of profit and losses

$ 455,000,000.0

50.00%

Collaboration and License Agreement | Amgen Inc | Amgen Products | Maximum

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Number of targets | Target

$ 950,000,000.0

Collaboration and License Agreement | Amgen Inc | Amgen Other Products

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

$ 4,800,000

Revenue recognition upon performance obligation

6 years

$ 4,800,000

Sublicense Agreement | Amgen Inc | UC Regents

2,400,000

3,000,000.0

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Sublicense Agreement | Amgen Inc | Maximum | UC Regents

$ 0

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

7.50%

[1]	The condensed balance sheet as of December 31, 2019 was derived from the audited financial statements included in the Company's Annual Report on Form 10-K for the year ended December 31, 2019.

Research and Collaboration Agreements - Astellas Pharma Inc - Additional Information (Details)

3 Months Ended

9 Months Ended

Mar. 23, 2020

USD ($)

Target

Sep. 30, 2020

USD ($)

Sep. 30, 2019

USD ($)

Sep. 30, 2020

USD ($)

Sep. 30, 2019

USD ($)

Dec. 31, 2019

USD ($)

$ 23,945,000

$ 30,051,000

^[1]

17,788,000

$ 10,712,000

83,989,000

$ 49,210,000

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

277,005,000

230,239,000

UCSB

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

$ 200,000

Astellas Pharma Inc.

Collaboration and License Agreement | Astellas Pharma Inc.

71,600,000

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Number of targets selected | Target

$ 80,000,000.0

80,000,000.0

Research and development service fees

90,000,000.0

$ 10,000,000.0

500,000

700,000

Estimated research service termination month & year

5 years

2025-03

4,500,000

9,100,000

71,600,000

Collaboration and License Agreement | Astellas Pharma Inc. | UC Regents

500,000

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaboration and License Agreement | Astellas Pharma Inc. | UCSB

7.50%

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaboration and License Agreement | Astellas Pharma Inc. | Additional Contingent Payments

$ 6,000,000.0

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaboration and License Agreement | Astellas Pharma Inc. | Maximum

$ 900,000,000

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Number of targets | Target

Right to expand the number of additional collaboration target | Target

Collaboration and License Agreement | Astellas Pharma Inc. | Minimum

$ 1,600,000,000

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Right to expand the number of additional collaboration target | Target

[1]	The condensed balance sheet as of December 31, 2019 was derived from the audited financial statements included in the Company's Annual Report on Form 10-K for the year ended December 31, 2019.

Research and Collaboration Agreements - Bristol-Myers Squibb Company - Additional Information (Details)

3 Months Ended

9 Months Ended

Apr. 25, 2017

USD ($)

Target

Jul. 07, 2014

USD ($)

Target

Term

Sep. 30, 2020

USD ($)

Mar. 31, 2020

USD ($)

Sep. 30, 2019

USD ($)

Mar. 31, 2019

USD ($)

Sep. 30, 2020

USD ($)

Sep. 30, 2019

USD ($)

Feb. 29, 2020

USD ($)

Dec. 31, 2019

USD ($)

Nov. 30, 2017

USD ($)

Dec. 31, 2016

USD ($)

Jan. 31, 2016

USD ($)

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

$ 17,788,000

$ 10,712,000

$ 83,989,000

$ 49,210,000

$ 23,945,000

$ 30,051,000

^[1]

us-gaap:LicenseAndServiceMember

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

$ 277,005,000

230,239,000

UCSB

Bristol Myers Squibb Company

200,000

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaborative Arrangement | Bristol Myers Squibb Company

135,700,000

$ 135,700,000

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaboration target research term

2 years

Extension of research term for each collaboration target

Research terms

Each collaboration target had a two-year research term and the two additional targets had to be nominated by Bristol Myers Squibb within five years of the effective date of the BMS Agreement. The research term for each collaboration target could be extended in one year increments up to three times.

1 year

$ 200,000,000.0

$ 50,000,000.0

Number of research targets selected | Target

$ 10,000,000.0

$ 15,000,000.0

$ 10,000,000.0

272,800,000

Research and development service fees

250,000,000.0

10,800,000

Estimated research service termination date

$ 12,000,000.0

$ 10,000,000.0

Apr. 25, 2025

$ 7,400,000

$ 32,200,000

$ 40,300,000

us-gaap:LicenseAndServiceMember

$ 135,700,000

158,000,000.0

Collaborative Arrangement | Bristol Myers Squibb Company | UC Regents

13,000

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaborative Arrangement | Bristol Myers Squibb Company | UCSB

7.50%

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaborative Arrangement | Bristol Myers Squibb Company | Pre-Clinical Candidate

$ 0

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaborative Arrangement | Bristol Myers Squibb Company | New Drug Application for CTLA-4

$ 2,000,000.0

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaborative Arrangement | Bristol Myers Squibb Company | Third And Fourth Immuno-Oncology Targets

$ 10,000,000.0

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaborative Arrangement | Maximum | Bristol Myers Squibb Company

$ 17,400,000

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Number of oncology target | Target

Number of collaboration target | Target

Period of nomination of additional target from effective date

5 years

Times of increments for extended collaboration target research time | Term

Collaborative Arrangement | Maximum | Bristol Myers Squibb Company | Each Of Two Additional Targets

$ 3,586,000,000.0

$ 1,192,000,000.0

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaboration and License Agreement | Maximum | Bristol Myers Squibb Company

$ 25,000,000.0

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]