Chinook Therapeutics (KDNY) 10-Q 3 Aug 20 2020 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2020	Jul. 29, 2020
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q2
Document Quarterly Report	true
Document Transition Report	false
Trading Symbol	ADRO
Security Exchange Name	NASDAQ
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Entity Interactive Data Current	Yes
Entity Registrant Name	ADURO BIOTECH, INC.
Entity Central Index Key	0001435049
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Shell Company	false
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Common Stock, Shares Outstanding		81,059,005
Entity Current Reporting Status	Yes
Entity File Number	001-37345
Entity Tax Identification Number	94-3348934
Entity Incorporation, State or Country Code	DE
Entity Address, Address Line One	740 Heinz Avenue
Entity Address, City or Town	Berkeley
Entity Address, State or Province	CA
Entity Address Postal Zip Code	94710
City Area Code	(510)
Local Phone Number	848-4400

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 71,103	$ 59,624
Marketable securities	100,028	153,978
Accounts receivable	1,169	342
Income tax receivable	5,665
Prepaid expenses and other current assets	3,015	3,958
Total current assets	180,980	217,902
Marketable securities	14,995
Property and equipment, net	21,706	24,688
Operating lease right-of-use assets	20,334	21,110
Goodwill	8,177	8,167
Intangible assets, net	18,723	18,978
Restricted cash	468	468
Total assets	265,383	291,313
Current liabilities:
Accounts payable	1,339	414
Accrued clinical trial and manufacturing expenses	2,615	4,253
Accrued expenses and other liabilities	9,673	8,181
Operating lease liabilities	1,741	1,803
Deferred revenue	4,935	6,950
Total current liabilities	20,303	21,601
Contingent consideration	2,013	1,051
Deferred revenue	161,312	166,963
Deferred tax liabilities	3,531	3,527
Operating lease liabilities	30,855	31,636
Other long-term liabilities	753	940
Total liabilities	218,767	225,718
Commitments and contingencies (Note 7)
Stockholders’ equity:
Preferred stock, $0.0001 par value; 10,000,000 shares authorized; no shares issued and outstanding at June 30, 2020 and December 31, 2019
Common stock, $0.0001 par value; 300,000,000 shares authorized; 81,059,005 and 80,735,688 shares issued and outstanding at June 30, 2020 and December 31, 2019	8	8
Additional paid-in capital	557,263	552,077
Accumulated other comprehensive income	439	414
Accumulated deficit	(511,094)	(486,904)
Total stockholders’ equity	46,616	65,595
Total liabilities and stockholders’ equity	$ 265,383	$ 291,313

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Jun. 30, 2020	Dec. 31, 2019
Statement Of Financial Position [Abstract]
Preferred stock par value per share	$ 0.0001	$ 0.0001
Preferred stock shares authorized	10,000,000	10,000,000
Preferred stock shares issued	0	0
Preferred stock shares outstanding	0	0
Common stock par value per share	$ 0.0001	$ 0.0001
Common stock shares authorized	300,000,000	300,000,000
Common stock shares issued	81,059,005	80,735,688
Common stock shares outstanding	81,059,005	80,735,688

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenue:
Total revenue	$ 5,574	$ 4,888	$ 19,524	$ 8,826
Operating expenses:
Research and development	11,108	16,657	26,936	34,151
General and administrative	9,284	7,832	17,103	16,056
Restructuring and related expense	2,046	367	6,354	3,361
Amortization of intangible assets	136	139	272	279
Total operating expenses	22,574	24,995	50,665	53,847
Loss from operations	(17,000)	(20,107)	(31,141)	(45,021)
Interest income	413	1,497	1,333	2,968
Other expense, net	(28)	(3)	(47)	(22)
Total other income	385	1,494	1,286	2,946
Loss before income tax	(16,615)	(18,613)	(29,855)	(42,075)
Income tax benefit		35	5,665	70
Net loss	$ (16,615)	$ (18,578)	$ (24,190)	$ (42,005)
Net loss per common share, basic and diluted	$ (0.21)	$ (0.23)	$ (0.30)	$ (0.53)
Shares used in computing net loss per common share, basic and diluted	80,862,621	80,032,022	80,810,211	79,847,960
Collaboration and license revenue
Revenue:
Total revenue	$ 5,574	$ 4,888	$ 19,524	$ 8,826

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (16,615)	$ (18,578)	$ (24,190)	$ (42,005)
Other comprehensive loss:
Unrealized gain on marketable securities, net of tax of $0	109	147	28	331
Foreign currency translation adjustments, net of tax of $0	470	404	(3)	(229)
Other comprehensive gain	579	551	25	102
Comprehensive loss	$ (16,036)	$ (18,027)	$ (24,165)	$ (41,903)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Comprehensive Loss (Unaudited) (Parenthetical) $ in Thousands	6 Months Ended
	Jun. 30, 2020USD ($)
Statement Of Income And Comprehensive Income [Abstract]
Unrealized (loss) gain on marketable securities, tax	$ 0
Foreign currency translation adjustments, tax	$ 0

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid In Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings
Beginning balance at Dec. 31, 2018	$ 135,311	$ 8	$ 538,895	$ 940	$ (404,532)
Beginning balance, Shares at Dec. 31, 2018		79,571,714
Issuance of common stock upon exercise of stock options	251		251
Issuance of common stock upon exercise of stock options, Shares		254,481
Release of restricted stock units		25,850
Stock-based compensation	3,703		3,703
Other comprehensive income (loss)	(449)			(449)
Net loss	(23,427)				(23,427)
Ending balance at Mar. 31, 2019	115,389	$ 8	542,849	491	(427,959)
Ending balance, Shares at Mar. 31, 2019		79,852,045
Beginning balance at Dec. 31, 2018	135,311	$ 8	538,895	940	(404,532)
Beginning balance, Shares at Dec. 31, 2018		79,571,714
Net loss	(42,005)
Ending balance at Jun. 30, 2019	101,050	$ 8	546,537	1,042	(446,537)
Ending balance, Shares at Jun. 30, 2019		80,130,274
Beginning balance at Mar. 31, 2019	115,389	$ 8	542,849	491	(427,959)
Beginning balance, Shares at Mar. 31, 2019		79,852,045
Issuance of common stock upon exercise of stock options	188		188
Issuance of common stock upon exercise of stock options, Shares		173,925
Issuance of common stock under Employee Stock Purchase Plan	164		164
Issuance of common stock under Employee Stock Purchase Plan, Shares		58,748
Release of restricted stock units		45,556
Stock-based compensation	3,336		3,336
Other comprehensive income (loss)	551			551
Net loss	(18,578)				(18,578)
Ending balance at Jun. 30, 2019	101,050	$ 8	546,537	1,042	(446,537)
Ending balance, Shares at Jun. 30, 2019		80,130,274
Beginning balance at Dec. 31, 2019	$ 65,595	$ 8	552,077	414	(486,904)
Beginning balance, Shares at Dec. 31, 2019	80,735,688	80,735,688
Issuance of common stock upon exercise of stock options	$ 80		80
Issuance of common stock upon exercise of stock options, Shares		88,480
Release of restricted stock units		12,925
Stock-based compensation	2,035		2,035
Other comprehensive income (loss)	(554)			(554)
Net loss	(7,575)				(7,575)
Ending balance at Mar. 31, 2020	59,581	$ 8	554,192	(140)	(494,479)
Ending balance, Shares at Mar. 31, 2020		80,837,093
Beginning balance at Dec. 31, 2019	$ 65,595	$ 8	552,077	414	(486,904)
Beginning balance, Shares at Dec. 31, 2019	80,735,688	80,735,688
Issuance of common stock upon exercise of stock options, Shares	91,460
Net loss	$ (24,190)
Ending balance at Jun. 30, 2020	$ 46,616	$ 8	557,263	439	(511,094)
Ending balance, Shares at Jun. 30, 2020	81,059,005	81,059,005
Beginning balance at Mar. 31, 2020	$ 59,581	$ 8	554,192	(140)	(494,479)
Beginning balance, Shares at Mar. 31, 2020		80,837,093
Issuance of common stock upon exercise of stock options	3		3
Issuance of common stock upon exercise of stock options, Shares		2,980
Issuance of common stock under Employee Stock Purchase Plan	40		40
Issuance of common stock under Employee Stock Purchase Plan, Shares		42,916
Release of restricted stock units		176,016
Stock-based compensation	3,028		3,028
Other comprehensive income (loss)	579			579
Net loss	(16,615)				(16,615)
Ending balance at Jun. 30, 2020	$ 46,616	$ 8	$ 557,263	$ 439	$ (511,094)
Ending balance, Shares at Jun. 30, 2020	81,059,005	81,059,005

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash Flows from Operating Activities
Net loss	$ (24,190)	$ (42,005)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	1,837	2,175
Amortization of intangible assets	272	279
Impairment of property and equipment	1,202	1,177
Non-cash lease expense	768	436
Accretion of discounts and amortization of premiums on marketable securities	(418)	(856)
Stock-based compensation	5,063	7,039
Loss from remeasurement of fair value of contingent consideration	943	24
Gain on disposal of property and equipment	(544)	(2)
Deferred income tax		(70)
Changes in operating assets and liabilities:
Accounts receivable	(820)	10,674
Income tax receivable	(5,665)
Prepaid expenses and other assets	938	612
Accounts payable	1,245	(349)
Deferred revenue	(7,666)	(6,763)
Accrued clinical trial and manufacturing expenses	(2,007)	1,359
Accrued expenses and other liabilities	1,056	(1,784)
Operating lease liabilities	(838)	468
Net cash used in operating activities	(28,824)	(27,586)
Cash Flows from Investing Activities
Purchase of marketable securities	(113,683)	(133,478)
Proceeds from maturities of marketable securities	153,082	114,159
Purchase of property and equipment	(9)	(382)
Proceeds from sale of property and equipment	544
Net cash provided by (used in) investing activities	39,934	(19,701)
Cash Flows from Financing Activities
Proceeds from employee stock purchase plan	40	164
Proceeds from exercise of stock options	83	439
Net cash provided by financing activities	123	603
Effect of exchange rate changes	246	(65)
Net increase (decrease) in cash, cash equivalents and restricted cash	11,479	(46,749)
Cash, cash equivalents and restricted cash at beginning of period	60,092	126,778
Cash, cash equivalents and restricted cash at end of period	71,571	80,029
Supplemental Disclosure of Non-Cash Investing and Financing Activities
Purchase of property and equipment in accounts payable and accrued liabilities	65
Reconciliation of Cash, Cash Equivalents and Restricted Cash
Cash and cash equivalents	71,103	79,561
Restricted cash	468	468
Cash, cash equivalents and restricted cash at end of period	$ 71,571	$ 80,029

Organization and Nature of Busi

Organization and Nature of Business	6 Months Ended
	Jun. 30, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Organization and Nature of Business	1. Organization and Nature of Business Aduro Biotech, Inc., and its wholly owned subsidiaries, or the Company, is an immunotherapy company focused on the discovery, development and commercialization of therapies that are designed to harness the body's natural immune system for the treatment of patients with challenging diseases. The Company is located in Berkeley, California and its wholly-owned subsidiary, Aduro Biotech Holdings, Europe B.V., or Aduro Biotech Europe, organized in the Netherlands. The Company operates in one business segment. The Company’s product candidates in the A Proliferation Inducing Ligand (APRIL) and Stimulator of Interferon Genes (STING) pathways are being investigated in cancer, autoimmune and inflammatory diseases. The Company’s anti-APRIL antibody product candidate, BION-1301, an investigational monoclonal antibody that blocks APRIL binding to both the BCMA and TACI receptors, is being evaluated in patients with IgA nephropathy. The Company’s lead STING pathway activator product candidate, ADU-S100 (MIW815), which is designed to activate the intracellular STING receptor, is being evaluated in combination with KEYTRUDA® (pembrolizumab), an approved anti-PD-1 monoclonal antibody, as a potential first-line treatment for patients with recurrent or metastatic squamous cell carcinoma of the head and neck (SCCHN). The Company is collaborating with leading global pharmaceutical companies to help expand and drive its product pipeline. The Company’s strategy is to rapidly advance therapeutic candidates from its APRIL and STING programs through clinical development and regulatory approval. On June 1, 2020, the Company entered into an Agreement and Plan of Merger and Reorganization, or the Merger Agreement, with Aspire Merger Sub, Inc., a Delaware corporation and a wholly owned subsidiary of the Company, or Merger Sub, and Chinook Therapeutics U.S., Inc., a Delaware corporation, or Chinook, pursuant to which, among other matters, and subject to the satisfaction or waiver of the conditions set forth in the Merger Agreement, Merger Sub will merge with and into Chinook, with Chinook continuing as a wholly owned subsidiary of the Company and the surviving corporation of the merger.

Basis of Presentation, Use of E

Basis of Presentation, Use of Estimates and Recent Accounting Pronouncements	6 Months Ended
	Jun. 30, 2020
Accounting Policies [Abstract]
Basis of Presentation, Use of Estimates and Recent Accounting Pronouncements	2. Basis of Presentation, Use of Estimates and Recent Accounting Pronouncements Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles, or U.S. GAAP, and follow the requirements of the Securities and Exchange Commission, or the SEC, for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by U.S. GAAP have been condensed or omitted, and accordingly the unaudited condensed consolidated financial statements do not include all of the information and notes required by U.S. GAAP for complete financial statements. These financial statements have been prepared on the same basis as the Company’s annual financial statements and, in the opinion of management, reflect all adjustments (consisting only of normal recurring adjustments) that are necessary for a fair presentation of the Company’s financial information. The results of operations for the three and six months ended June 30, 2020 are not necessarily indicative of the results to be expected for the year ending December 31, 2020 or for any other interim period or for any other future year. The accompanying condensed consolidated financial statements and related financial information should be read in conjunction with the audited consolidated financial statements and the related notes thereto for the year ended December 31, 2019 included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2019 filed with the SEC on March 9, 2020. The condensed consolidated financial statements include the accounts of Aduro Biotech, Inc. and its wholly-owned subsidiaries. All intercompany transactions and balances have been eliminated. Use of Estimates The preparation of 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 and reported amounts of revenue and expenses in the financial statements and accompanying notes. On an ongoing basis, management evaluates its estimates, including those related to revenue recognition, clinical trial accruals, contingent consideration, income taxes, right-of-use assets, lease obligations, stock-based compensation, and valuation of intangibles and goodwill. Management bases its estimates on historical experience and on various other market-specific and relevant assumptions that management believes to be reasonable under the circumstances. Actual results could differ from these estimates. Recent Accounting Pronouncements In June 2016, the Financial Accounting Standards Board, or FASB, issued Accounting Standard Update, or ASU, No. 2016-13 – Financial Instruments—Credit Losses (Topic 326). The standard changes how entities will measure credit losses for most financial assets and certain other instruments that are not measured at fair value through net income. Financial assets measured at amortized cost will be presented at the net amount expected to be collected by using an allowance for credit losses. In April 2019, the FASB issued ASU No. 2019-04, Codification Improvements to Topic 326, Financial Instruments – Credit Losses, Topic 815, Derivatives and Hedging, and Topic 825, Financial Instruments, which clarifies and corrects certain unintended applications of the guidance contained in each of the amended Topics. Additionally, in May 2019, the FASB issued ASU No. 2019-05, Financial Instruments – Credit Losses (Topic 326), which provides an option to irrevocably elect to measure certain individual financial assets at fair value instead of amortized cost. In November 2019, the FASB issued ASU No. 2019-10, Financial Instruments – Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842), which defers the effective date for ASU No. 2016-13 for smaller reporting companies to fiscal years beginning after December 15, 2022, including interim periods within those fiscal years. Early adoption is permitted for all periods beginning after December 15, 2018. The Company does not plan to early adopt and is currently in the process of evaluating the impact the standard will have on its consolidated financial statements. In December 2019, the FASB issued ASU No. 2019-12 – Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes (ASU 2019-12). The standard update simplifies the accounting for income taxes by removing certain exceptions to the general principles in ASC 740 and also improves consistent application by clarifying and amending existing guidance. The standard is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020. Early adoption is permitted. The Company has evaluated the impact of this guidance and has concluded that adoption of the standard will not have a material impact on its consolidated financial statements. Recently Adopted Accounting Pronouncements In August 2018, the FASB issued ASU No. 2018-13 – Fair Value Measurement (Topic 820): Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement. The standard eliminates certain disclosure requirements for fair value measurements for all entities, requires public entities to disclose certain new information, and modifies some disclosure requirements. The new standard is effective for fiscal years and interim periods beginning after December 15, 2019. The Company adopted the new standard on January 1, 2020. As the result of the adoption the Company is no longer required to disclose (1) the amount of and the reasons for transfers between Level 1 and Level 2 of the fair value hierarchy, (2) the policy for timing of transfers between levels, and (3) the valuation process for Level 3 fair value measurements. Additionally, the Company is required to disclose (1) the changes in unrealized gains and losses for the period included in other comprehensive income (loss) for recurring Level 3 fair value measurements held at the end of the reporting period and (2) the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. Refer to Note 3 “Fair Value Measurements” for the newly required disclosures resulting from the adoption of this standard.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	3. Fair Value Measurements The carrying amounts of certain of the Company’s financial instruments, including cash equivalents, accounts receivable and accounts payable approximate their fair values due to their short maturities. Assets and liabilities recorded at fair value on a recurring basis in the balance sheets, as well as assets and liabilities measured at fair value on a non-recurring basis or disclosed at fair value, are categorized based upon the level of judgment associated with inputs used to measure their fair values. The accounting guidance for fair value provides a framework for measuring fair value and requires certain disclosures about how fair value is determined. Fair value is defined as the price that would be received upon the sale of an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the reporting date. The accounting guidance also establishes a three-level valuation hierarchy that prioritizes the inputs to valuation techniques used to measure fair value based upon whether such inputs are observable or unobservable. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect market assumptions made by the reporting entity. The three-level hierarchy for the inputs to valuation techniques is briefly summarized as follows: Level 1 —Inputs are unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date; Level 2 —Inputs are observable, unadjusted quoted prices in active markets for similar assets or liabilities, unadjusted quoted prices for identical or similar assets or liabilities 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 related assets or liabilities; and Level 3 —Unobservable inputs that are significant to the measurement of the fair value of the assets or liabilities that are supported by little or no market data. The Company’s cash equivalents , which include money market funds , are classified as Level 1 because they are valued using quoted market prices. The Company’s cash equivalents consisting of corporate debt securities and commercial paper along with the Company’s marketable securities consist ing of available-for-sale securities are generally classified as Level 2 because their value is based on valuations using significant inputs derived from or corroborated by observable market data. When quoted prices in active markets for identical assets or liabilities are not available, the Company relies on non-binding quotes from its investment managers, which are based on proprietary valuation models of independent pricing services. These models generally use inputs such as observable market data, quoted market prices for similar instruments, or historical pricing trends of a security relative to its peers. To validate the fair value determination provided by its investment managers, the Company reviews the pricing movement in the context of overall market trends and trading information from its investment managers. In addition, the Company assesses the inputs and methods used in determining the fair value in order to determine the classification of securities in the fair value hierarchy. In certain cases where there is limited activity or less transparency around the inputs to valuation, securities are classified as Level 3. Level 3 liabilities consist of the contingent consideration liability. The following table sets forth the Company’s financial instruments that were measured at fair value on a recurring basis by level within the fair value hierarchy (in thousands): June 30, 2020 Level 1 Level 2 Level 3 Total Financial Assets: Money market funds $ 30,913 $ — $ — $ 30,913 U.S. government and agency securities — 66,209 — 66,209 Corporate debt securities — 17,702 — 17,702 Commercial paper — 67,304 — 67,304 Total $ 30,913 $ 151,215 $ — $ 182,128 Financial Liabilities: Contingent consideration related to acquisition $ — $ — $ 2,013 $ 2,013 Total $ — $ — $ 2,013 $ 2,013 December 31, 2019 Level 1 Level 2 Level 3 Total Financial Assets: Money market funds $ 39,994 $ — $ — $ 39,994 U.S. government and agency securities — 43,333 — 43,333 Corporate debt securities — 54,590 — 54,590 Commercial paper — 67,536 — 67,536 Total $ 39,994 $ 165,459 $ — $ 205,453 Financial Liabilities: Contingent consideration related to acquisition $ — $ — $ 1,051 $ 1,051 Total $ — $ — $ 1,051 $ 1,051 The acquisition-date fair value of the contingent consideration liability represents the future consideration that is contingent upon the achievement of specified development milestones for a product candidate. The fair value of the contingent consideration is based on the Company’s probability-weighted discounted cash flow assessment that considers probability and timing of future payments. The fair value measurement is based on significant Level 3 unobservable inputs such as the probability of achieving development milestones, anticipated timelines and discount rate, the values of which as of June 30, 2020 are shown in the table below. Changes in the fair value of the liability for contingent consideration will be recognized in the consolidated statement of operations until settlement. Unobservable Input Probability of attaining milestone 18.8 % Period of time to achieve milestone (in years) 7.5 Discount rate 10.0 % The Company did not have any financial assets and liabilities measured at fair value on a non-recurring basis as of June 30, 2020 and December 31, 2019. The following table sets forth a summary of the changes in the fair value of the Company’s Level 3 financial liabilities (in thousands): Contingent Consideration Balance at December 31, 2019 $ 1,051 Net change in fair value upon remeasurement 943 Foreign currency impact on contingent consideration 19 Balance at June 30, 2020 $ 2,013 The following tables summarize the estimated value of the Company’s cash, cash equivalents and marketable securities and the gross unrealized holding gains and losses (in thousands): June 30, 2020 Amortized cost Unrealized gains Unrealized losses Estimated Fair Value Cash and cash equivalents: Cash $ 3,998 $ — $ — $ 3,998 Money market funds 30,913 — — 30,913 Commercial paper 29,791 2 (1 ) 29,792 U.S. government and agency securities 6,400 — — 6,400 Total cash and cash equivalents $ 71,102 $ 2 $ (1 ) $ 71,103 Marketable securities: U.S. government and agency securities $ 59,800 $ 20 $ (11 ) $ 59,809 Corporate debt securities 17,639 63 — 17,702 Commercial paper 37,493 20 (1 ) 37,512 Total marketable securities $ 114,932 $ 103 $ (12 ) $ 115,023 December 31, 2019 Amortized cost Unrealized gains Unrealized losses Estimated Fair Value Cash and cash equivalents: Cash $ 8,149 $ — $ — $ 8,149 Money market funds 39,994 — — 39,994 Commercial paper 11,482 — (1 ) 11,481 Total cash and cash equivalents $ 59,625 $ — $ (1 ) $ 59,624 Marketable securities: U.S. government and agency securities $ 43,295 $ 40 $ (2 ) $ 43,333 Corporate debt securities 54,563 33 (6 ) 54,590 Commercial paper 56,055 7 (7 ) 56,055 Total marketable securities $ 153,913 $ 80 $ (15 ) $ 153,978 The amortized cost and estimated fair value of the Company’s available-for-sale marketable securities by contractual maturity are summarized below as of June 30, 2020 (in thousands): Amortized cost Unrealized gains Unrealized losses Estimated Fair Mature in one year or less $ 99,936 $ 102 $ (10 ) $ 100,028 Mature after one year through two years 14,996 1 (2 ) 14,995 Total available-for-sale marketable securities $ 114,932 $ 103 $ (12 ) $ 115,023

Balance Sheet Components

Balance Sheet Components	6 Months Ended
	Jun. 30, 2020
Balance Sheet Related Disclosures [Abstract]
Balance Sheet Components	4. Balance Sheet Components Property and Equipment, Net Property and equipment, net consisted of the following (in thousands): June 30, December 31, 2020 2019 Leasehold improvements $ 27,084 $ 27,288 Lab equipment 6,046 8,817 Computer and office equipment 2,146 2,334 Furniture 1,427 1,590 Construction in progress 122 190 Total property and equipment 36,825 40,219 Less: accumulated depreciation (15,119 ) (15,531 ) Property and equipment, net $ 21,706 $ 24,688 Depreciation expense was $0.8 million and $1.1 million for the three months ended June 30, 2020 and 2019, respectively and $1.8 million and $2.2 million for the six months ended June 30, 2020 and 2019, respectively. Accrued Expenses and Other Liabilities Accrued expenses and other liabilities consisted of the following (in thousands): June 30, December 31, 2020 2019 Compensation and related benefits $ 4,539 $ 3,677 Professional and consulting services 3,410 2,845 Accrued research expense 895 890 Accrued purchases of property and equipment 23 31 Other 806 738 Total accrued expenses and other liabilities $ 9,673 $ 8,181

Goodwill and Intangible Assets

Goodwill and Intangible Assets	6 Months Ended
	Jun. 30, 2020
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	5. Goodwill and Intangible Assets Goodwill The gross carrying amount of goodwill was as follows (in thousands): Balance at December 31, 2019 $ 8,167 Foreign currency translation adjustment 10 Balance at June 30, 2020 $ 8,177 The Company tests goodwill for impairment on an annual basis on November 1, or more frequently if an impairment indicator exists. To determine if an impairment has occurred, the Company performs a quantitative test in which the Company compares the fair value of its single reporting unit to its carrying value. If the carrying value of the reporting unit exceeds the fair value of the reporting unit, the Company records an impairment loss equal to that difference. As a result of the Company’s planned closure of its European site, the Company performed a quantitative assessment of goodwill as of March 31, 2020, and concluded that there was no impairment of goodwill as the fair value of the Company’s reporting unit exceeded its carrying value. Intangible assets The gross carrying amounts and net book value of intangible assets were as follows (in thousands): June 30, 2020 Gross Amount Accumulated Amortization Net Book Value Intangible assets with finite lives: License agreement $ 11,104 $ 2,591 $ 8,513 Total intangible assets with finite lives 11,104 2,591 8,513 Acquired IPR&D assets 10,210 — 10,210 Total intangible assets $ 21,314 $ 2,591 $ 18,723 December 31, 2019 Gross Amount Impairment (1) Accumulated Amortization Net Book Value Intangible assets with finite lives: License agreement $ 11,091 $ — $ 2,311 $ 8,780 Total intangible assets with finite lives 11,091 — 2,311 8,780 Acquired IPR&D assets 15,297 5,099 — 10,198 Total intangible assets $ 26,388 $ 5,099 $ 2,311 $ 18,978 (1) The amount includes effects of foreign currency exchange rates. Intangible assets are carried at cost less accumulated amortization and impairment. Amortization is over a period of 20 years and the amortization expense is recorded in operating expenses. The Company tests its Acquired IPR&D intangible assets for impairment on an annual basis, or more frequently if an impairment indicator exists. In the first quarter of 2020, due to the Company’s decision to close its European site, the Company assessed its Acquired IPR&D intangible assets for impairment. Based on the qualitative assessment performed, no impairment of Acquired IPR&D intangible assets was recorded as of June 30, 2020. Amortization expense was $0.1 million for each of the three months ended June 30, 2020 and 2019 and $0.3 million for each of the six months ended June 30, 2020 and 2019. Based on finite-lived intangible assets recorded as of June 30, 2020, the estimated future amortization expense for the next five years is as follows (in thousands): Year Ending December 31, Estimated Amortization Expense 2020 (remaining six months) $ 278 2021 555 2022 555 2023 555 2024 555 2025 555

Collaboration Agreements

Collaboration Agreements	6 Months Ended
	Jun. 30, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Collaboration Agreements	6. Collaboration Agreements Novartis Agreement I n March 2015, the Company entered into a collaboration and license agreement with Novartis Pharmaceuticals Corporation, or Novartis, pursuant to which the Company is collaborating worldwide with Novartis regarding the development and potential commercialization of product candidates containing an agonist of the molecular target known as STING in the field of oncology, including immuno-oncology and cancer vaccines. Under this agreement, or the Novartis Agreement, the Company granted Novartis a co-exclusive license to develop such products worldwide, an exclusive license to commercialize such products outside the United States and a non-exclusive license to support the Company in commercializing such products in the United States if it requests such support. The collaboration is guided by a joint steering committee with each party having final decision-making authority regarding specified areas of development or commercialization. Under the Novartis Agreement, the Company received an upfront payment of $200.0 million in April 2015. During the second quarter of 2016, the Company earned a $35.0 million development milestone upon initiation of a Phase 1 trial for the first STING product candidate, ADU-S100, and recognized the payment as revenue in the period. The Company is also eligible to receive up to an additional $215.0 million in development milestones and up to an additional $250.0 million in regulatory approval milestones. The Company is responsible for 38% of the joint development costs worldwide and Novartis is responsible for the remaining 62% of the joint development costs worldwide; provided that either party may opt out of early stage clinical trials subject to an obligation to fund and participate in any pivotal trials and reimburse certain early development costs if development of the product progresses into pivotal trials. The Company will also receive 50% of gross profits on sales of any products commercialized pursuant to this collaboration in the United States and 45% of gross profits for specified European countries and Japan. For each of these profit share countries, each party will be responsible for its respective commercial sharing percentage of all joint commercialization costs incurred in that country. For all other countries where the Company is not sharing profits, Novartis will be responsible for all commercialization costs and will pay the Company a royalty in the mid-teens on all net sales of product sold by Novartis, its affiliates and sublicensees, with such percentage subject to reduction post patent and data exclusivity expiration and subject to reduction, capped at a specified percentage, for royalties payable to third party licensors. Novartis’ royalty obligation will run on a country-by-country basis until the later of expiration of the last valid claim covering the product, expiration of data exclusivity for the product or 12 years after first commercial sale of the product in such country. With respect to the United States, specified European countries and/or Japan, the Company may elect for such region to either reduce by 50% or to eliminate in full the Company’s development and commercialization cost sharing obligation. If the Company elects to reduce its cost sharing percentage by 50% in any such region, then its profit share in such region will also be reduced by 50%. If the Company elects to eliminate its development cost sharing obligation, then such region will be removed from the profit share, and instead Novartis will owe the Company royalties on any net sales of product for such region, as described above. For revenue recognition purposes, the Company determined that the duration of the contract begins on the effective date in March 2015 and ends upon receipt of regulatory approval, estimated to occur in 2028. The Company’s performance period commenced in May 2015. The transaction price consists of the $200.0 million upfront fee, a $35.0 million milestone payment received in the second quarter of 2016 upon commencement of a Phase 1 study, and $2.1 million in reimbursement of research and development costs through June 30, 2020. The Company determined that the remaining potential milestone payments are probable of significant reversal of cumulative revenue as their achievement is highly dependent on the successful completion of Phase 1 studies. Therefore, these payments are not included in the transaction price. Any consideration related to sales-based royalties and profit-sharing payments will be recognized when the related sales occur as they were determined to relate predominantly to the license granted to Novartis and have been excluded from the transaction price. The transaction price of $237.1 million is allocated to one combined performance obligation. The Company will re-evaluate the transaction price in each reporting period and as uncertain events are resolved or other changes in circumstances occur. The Company concluded that it will utilize a cost-based input method to measure its progress toward completion of its performance obligation and to calculate the corresponding amount of revenue to recognize each period. The Company believes this is the best measure of progress because other measures do not reflect how the Company transfers its performance obligation to Novartis. In applying the cost-based input method of revenue recognition, the Company uses actual clinical study enrollment figures as well as actual costs incurred relative to budgeted costs expected to be incurred for the combined performance obligation. These costs consist primarily of internal full-time equivalent effort and third-party contract costs relative to the level of patient enrollment in the study. Revenue will be recognized based on the level of costs incurred relative to the total budgeted costs for the performance obligations and it is dependent on the clinical timelines and progress under the research and collaboration agreement. A cost-based input method of revenue recognition requires management to make estimates of costs to complete the Company's performance obligation. In making such estimates, significant judgment is required to evaluate assumptions related to cost estimates. The cumulative effect of revisions to estimated costs to complete the Company's performance obligation will be recorded in the period in which changes are identified and amounts can be reasonably estimated. A significant change in these assumptions and estimates could have a material impact on the timing and amount of revenue recognized in future periods. Cost-sharing payments from Novartis are included in the transaction price and subject to the cost-based input method to determine the amount to be recognized in license and collaboration revenue in the Company’s consolidated statements of operations, while cost-sharing payments to Novartis are accounted for as research and development expenses in the Company’s consolidated statements of operations. If the Company recognizes revenue from the sale of any products commercialized pursuant to this collaboration in the United States, it will retain 50% of the gross profits from such sales and will pay the remaining 50% of the gross profits to Novartis. The Company will receive from Novartis 45% of gross profits for specified European countries and Japan from the sale of any products commercialized pursuant to this collaboration in such countries. Profit sharing payments made to or received from Novartis will be aggregated by product by territory and reported as expenses or revenues, as applicable. In December 2019, the Company received notification that Novartis has removed ADU-S100 (MIW815), an intratumoral STING pathway activator product candidate, from Novartis’ portfolio based on clinical data generated to date. This decision was not the result of any safety concern. The collaboration and license agreement between Novartis and Aduro remains in effect, and both parties continue to jointly pursue STING pathway activation through systemic delivery as a therapeutic strategy. The removal of ADU-S100 from Novartis’ portfolio did not have an impact on the overall transaction price nor the revenue recognition methodology being utilized by the Company. The Company is funding the squamous cell carcinoma of the head and neck and preparation of the IND application for any non-muscle invasive bladder cancer studies evaluating ADU-S100 itself because Novartis has opted out of these trials. For the three months ended June 30, 2020 and 2019, the Company recognized $3.9 million and $1.9 million, respectively, and for the six months ended June 30, 2020 and 2019, the Company recognized $5.7 million and $4.4 million, respectively, in revenue from its collaboration with Novartis. The remaining balance of the upfront fee of $163.3 million is included in deferred revenue at June 30, 2020. Lilly Agreement On December 18, 2018, the Company entered into a research collaboration and exclusive license agreement, or the Lilly Agreement, with Lilly for its cGAS-STING Pathway Inhibitor program for the research and development of novel immunotherapies for autoimmune and other inflammatory diseases. Pursuant to the Lilly Agreement, the Company granted an exclusive and worldwide license under certain intellectual property rights controlled by the Company to research, develop, manufacture and commercialize certain cGAS-STING products for the treatment of autoimmune and other inflammatory diseases. The license granted is sublicensable during a specified time period. Under the terms of the Lilly Agreement, the Company received an upfront payment of $12.0 million in the first quarter of 2019. The Company will also be eligible for development and commercial milestones of up to approximately $620.0 million per product. Lilly is also obligated to pay the Company tiered royalty payments at percentages in the single to low-double digits based on annual net sales of the licensed products. Lilly must pay such royalties on a product-by-product and country-by-country basis until the latest to occur of (i) the expiration of the last-to-expire valid claim of certain patents, (ii) the expiration of the data exclusivity period in such country or (iii) a specified anniversary of the first commercial sale of such product in such country. The Company will be reimbursed for up to a certain amount of research funding spent during the research term. In addition, the Company has the option to co-fund the clinical development of each product in exchange for an increase in royalty payments and a reduction in certain milestone payments to the extent relevant to such co-funded product. Lilly will be responsible for all costs of global commercialization. For revenue recognition purposes, the Company determined that the Company’s performance period commenced in January 2019 and ends upon completion of the research term, estimated to occur in 2021. The transaction price consists of the $12.0 million upfront fee and variable consideration related to reimbursement of research and development costs. The Company determined that the remaining potential milestone payments are probable of significant reversal of cumulative revenue as their achievement is highly dependent on the successful completion of research activities and advancement through clinical studies. Therefore, these potential milestone payments are not included in the transaction price. Any consideration related to sales-based royalties and profit-sharing payments will be recognized when the related sales occur as they were determined to relate predominantly to the license granted to Lilly and have been excluded from the transaction price. The transaction price is allocated to one combined performance obligation. The Company will re-evaluate the transaction price in each reporting period and as uncertain events are resolved or other changes in circumstances occur. The Company concluded that it will utilize a cost-based input method to measure its progress toward completion of its performance obligation and to calculate the corresponding amount of revenue to recognize each period. The Company believes this is the best measure of progress because other measures do not reflect how the Company transfers its performance obligation to Lilly. In applying the cost-based input method of revenue recognition, the Company uses actual costs incurred relative to budgeted costs expected to be incurred for the combined performance obligation. These costs consist primarily of internal full-time equivalent effort and third-party contract costs. Revenue will be recognized based on the level of costs incurred relative to the total budgeted costs for the performance obligation. A cost-based input method of revenue recognition requires management to make estimates of costs to complete the Company's performance obligation. In making such estimates, significant judgment is required to evaluate assumptions related to cost estimates. The cumulative effect of revisions to estimated costs to complete the Company's performance obligation will be recorded in the period in which changes are identified and amounts can be reasonably estimated. A significant change in these assumptions and estimates could have a material impact on the timing and amount of revenue recognized in future periods. For the three months ended June 30, 2020 and 2019, the Company recognized $1.7 million and $3.0 million, respectively, in revenue. For the six months ended June 30, 2020 and 2019, the Company recognized $3.9 million and $4.4 million, respectively, in revenue from the Lilly Agreement. The Company recorded $2.9 million in deferred revenue at June 30, 2020. Merck License Agreement In connection with the acquisition of Aduro Biotech Europe in October 2015, the Company became party to an agreement with Merck Sharp & Dohme Corp., or Merck. The agreement sets forth the parties’ respective obligations for development, commercialization, regulatory and manufacturing and supply activities for antibody product candidates. The Company identified the following promises under the agreement: 1) the license, 2) the obligation to provide research activities and 3) the obligation to participate on a Joint Research Committee. The Company determined that the promises were not distinct which resulted in them being combined into one performance obligation. The Company completed its performance obligation under the agreement by the end of 2016. The Company received a milestone payment of $2.0 million in 2017 for the initiation of a Good Laboratory Practice, or GLP, toxicology study and $3.0 million in the first quarter of 2018 for the initiation of a Phase 1 trial for the anti-CD27 antibody and $10.0 million in the first quarter of 2020 for the initiation of a Phase II trial for the anti-CD27 antibody. The payments were recognized in revenue when received as the Company had no remaining performance obligation. The Company is eligible to receive future contingent payments, including up to $297.0 million in potential development milestone payments, and up to $135.0 million in commercial and net sales milestones for a product candidate. In addition, the Company is eligible to receive royalties in the mid-single digits to low teens based on net sales of the product. Future milestone payments and royalties will be recognized when earned as the Company has no remaining performance obligations under this agreement. For the three months ended June 30, 2020, the Company recognized no revenue from its collaboration with Merck while for the six months ended June 30, 2020, the Company recognized a $10.0 million milestone payment related to the initiation of a Phase II trial for the anti-CD27 antibody.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2020
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	7. Commitments and Contingencies Leases The Company leases one facility in Berkeley, California under an operating lease that has a remaining lease term of approximately 10 years. The Company also leased one facility in Oss, the Netherlands, under an operating lease that was set to expire in December 2020. In June 2020, the Company terminated its lease agreement for its leased facility in connection with the closure of its European site in Oss, the Netherlands. The Company will continue to pay the lease obligation, which is reimbursable to the Company if the landlord enters into a new lease agreement with a new tenant, until the original expiration of the lease agreement in December 2020. Both leases contain an option to extend for an additional term, however, the Company is not reasonably certain to exercise the option for the Berkeley lease and the Company will not be exercising the option for the Oss lease due to the closure of the Oss facility in June 2020. Refer to Note 10 “Restructuring and Related Expense” for additional information. The Company is subleasing approximately 26,552 square feet in its Berkeley facility under subleases that expire on or prior to February 28, 2021. Sublease income was $0.4 million for each of the three months ended June 30, 2020 and 2019, and $0.7 million and $0.8 million for the six months ended June 30, 2020 and 2019, respectively. During 2016, the Company established a letter of credit with Bank of America Merrill Lynch as security for the Berkeley lease in the amount of $0.5 million. The letter of credit is collateralized by a certificate of deposit for $0.5 million which has been included in restricted cash in the consolidated balance sheet as of June 30, 2020. The maturity of the Company’s operating lease liabilities as of June 30, 2020 is as follows (in thousands): Undiscounted Lease Payments Amounts 2020 (remaining six months) $ 2,862 2021 5,332 2022 5,460 2023 5,569 2024 5,681 Thereafter 30,155 Total undiscounted lease payments 55,059 Present value adjustment 22,463 Total net lease liability $ 32,596 Net lease liability - current $ 1,741 Net lease liability - non-current 30,855 Total net lease liability $ 32,596 Straight-line rent expense recognized for operating leases was $1.4 million and $1.2 million for the three months ended June 30, 2020 and 2019, respectively, and $2.7 million and $2.5 million for the six months ended June 30, 2020 and 2019, respectively. Variable lease payments, including non-lease components such as common area maintenance fees, recognized as rent expense for operating leases was $0.3 million for each of the three months ended June 30, 2020 and 2019, and $0.7 million and $0.6 million for the six months ended June 30, 2020 and 2019, respectively. The Company does not have any finance leases. The following information represents supplemental disclosure for the condensed consolidated statement of cash flows related to operating leases (in thousands): Six months ended June 30, 2020 2019 Cash flows from operating activities Cash paid for amounts included in the measurement of lease liabilities $ 2,798 $ 2,727 The following summarizes additional information related to operating leases: June 30, 2020 June 30, 2019 Weighted-average remaining lease terms (in years) Operating leases 9.4 10.3 Weighted-average discount rate Operating leases 12% 12% Indemnification In the ordinary course of business, the Company enters into agreements that may include indemnification provisions. Pursuant to such agreements, the Company may indemnify, hold harmless and defend an indemnified party for losses suffered or incurred by the indemnified party. Some of the provisions will limit losses to those arising from third party actions. In some cases, the indemnification will continue after the termination of the agreement. The maximum potential amount of future payments the Company could be required to make under these provisions is not determinable. The Company has never incurred material costs to defend lawsuits or settle claims related to these indemnification provisions. The Company has also entered into indemnification agreements with its directors and officers that may require the Company to indemnify its directors and officers against liabilities that may arise by reason of their status or service as directors or officers to the fullest extent permitted by Delaware corporate law. The Company currently has directors’ and officers’ insurance. Legal The Company is not party to any material legal proceedings at this time. From time to time, the Company may become involved in various legal proceedings that arise in the ordinary course of its business. Other Commitments The Company has various manufacturing, clinical, research and other contracts with vendors in the conduct of the normal course of its business. All contracts are terminable, with varying provisions regarding termination. If a contract with a specific vendor were to be terminated, the Company would only be obligated for the products or services that the Company had received at the time the termination became effective as well as non-cancelable and non-refundable obligations, including payment obligations for costs or expenses incurred by the vendor for products or services before the termination became effective. In the case of terminating a clinical trial agreement at a particular site, the Company would also be obligated to provide continued support for appropriate medical procedures at that site until completion or termination.

Common Stock

Common Stock	6 Months Ended
	Jun. 30, 2020
Equity [Abstract]
Common Stock	8. Common Stock The Company had reserved shares of common stock for future issuance as follows: June 30, 2020 Options issued and outstanding 11,317,276 Shares available for future stock option grants 10,941,502 Restricted stock units 526,995 Common stock warrants 50,162 Total 22,835,935 At-the-Market Sales Agreement In August 2017, the Company entered into an “at-the-market” sales agreement, as amended in February 2019, or the 2017 Sales Agreement, with Cowen, through which the Company may offer and sell shares of its common stock having an aggregate offering of up to $100.0 million through Cowen, as the Company’s sales agent. The Company will pay Cowen a commission of up to 3% of the gross proceeds of sales made through the arrangement. There were no sales of shares of common stock pursuant to the 2017 Sales Agreement during the year ended December 31, 2019 or the six months ended June 30, 2020. As of June 30, 2020, the Company had an aggregate of $81.5 million remaining for future sales under the 2017 Sales Agreement, subject to the continued effectiveness of its shelf registration statement on Form S-3 (Registration No. 333-219639), which expires on August 11, 2020, or an effective replacement shelf registration statement.

Equity Incentive Plans

Equity Incentive Plans	6 Months Ended
	Jun. 30, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Equity Incentive Plans	9. Equity Incentive Plans 2015 Plan In March 2015, the Company’s board of directors adopted and in April 2015 the Company’s stockholders approved the 2015 Equity Incentive Plan, or the 2015 Plan, which became effective upon the initial public offering of the Company’s common stock, or IPO, and provides for the granting of incentive stock options, nonstatutory stock options and other forms of stock awards to its employees, directors and consultants. The Company’s 2009 Stock Incentive Plan, or the 2009 Plan, terminated on the date the 2015 Plan was adopted. Options granted or shares issued under the 2009 Plan that were outstanding on the date the 2015 Plan became effective will remain subject to the terms of the 2009 Plan. The 2015 Plan is administered by the board of directors or a committee appointed by the board of directors, which determines the types of awards to be granted, including the number of shares subject to the awards, the exercise price and the vesting schedule. The exercise price of incentive stock options and nonqualified stock options will be no less than 100% of the fair value per share of the Company’s common stock on the date of grant. If an individual owns capital stock representing more than 10% of the voting shares, the price of each share will be at least 110% of the fair value on the date of grant. Options expire after 10 years (five years for stockholders owning greater than 10% of the voting stock). The number of shares of common stock initially reserved for issuance under the 2015 Plan was 6,134,292 shares with an automatic annual increase to the shares issuable under the 2015 Plan to the lower of (i) 4% of the total number of shares of common stock outstanding on December 31 of the preceding calendar year, or (ii) a lower number determined by the board of directors. On January 1, 2020, the shares issuable under the 2015 Plan increased by 3,229,427. The Company had 10,941,502 shares available for future grant under the 2015 Plan as of June 30, 2020. 2009 Plan The Company’s 2009 Stock Incentive Plan, or the 2009 Plan, terminated on the date the 2015 Plan was adopted. Options granted or shares issued under the 2009 Plan that were outstanding on the date the 2015 Plan became effective will remain subject to the terms of the 2009 Plan. Prior to the 2009 Plan termination, the number of options available for grant was increased by 360,000 shares. At June 30, 2020, 2,691,784 options under the 2009 Plan remained outstanding. Stock Options The following table summarizes stock option activity for the six months ended June 30, 2020: Options Outstanding Shares Available for Grant Number of Shares Underlying Options Weighted- Average Exercise Price Aggregate Intrinsic Value (In thousands) Balance—December 31, 2019 8,751,436 10,297,444 $ 5.49 $ 680 Authorized 3,229,427 — RSUs forfeited, net 83,007 — Granted (3,136,000 ) 3,136,000 3.14 Exercised — (91,460 ) 0.91 Canceled 2,013,632 (1) (2,024,708 ) 5.87 Balance—June 30, 2020 10,941,502 11,317,276 $ 4.81 $ 3,671 Options exercisable—June 30, 2020 6,264,788 $ 5.82 $ 3,369 Options vested and expected to vest—June 30, 2020 10,204,429 $ 4.97 $ 3,608 (1) The aggregate intrinsic value represents the difference between the exercise price of the options and the closing price of the Company’s common stock. The aggregate intrinsic value of options exercised during the six months ended June 30, 2020 was $0.1 million. As of June 30, 2020, the total unrecognized compensation expense related to unvested options, net of estimated forfeitures, was $9.0 million, which the Company expects to recognize over an estimated weighted-average period of 2.9 years. Restricted Stock Units (RSUs) In September 2016, the Company’s board of directors authorized the issuance of restricted stock units, or RSUs, under the 2015 Plan and adopted a form of restricted stock unit grant notice and restricted stock unit award agreement, which is intended to serve as a standard form agreement for RSU grants issued to employees, executive officers, directors and consultants. The following table summarizes RSU activity for the six months ended June 30, 2020: RSUs Outstanding Number of Restricted Units Weighted- Average Grant Date Fair Share Balance—December 31, 2019 798,943 $ 7.40 Granted 109,124 3.37 Vested (188,941 ) 3.99 Forfeited (192,131 ) 8.34 Balance—June 30, 2020 526,995 $ 7.45 The fair value of RSUs is determined on the date of grant based on the market price of the Company’s common stock on that date. As of June 30, 2020, there was $1.8 million of unrecognized stock-based compensation expense, net of estimated forfeitures, related to RSUs which is expected to be recognized over a weighted-average period of 1.8 years. 2015 Employee Stock Purchase Plan In March 2015, the Company’s board of directors adopted and in April 2015 the Company’s stockholders approved the 2015 Employee Stock Purchase Plan, or 2015 ESPP, which became effective upon the IPO. The 2015 ESPP is intended to qualify as an employee stock purchase plan under Section 423 of the Internal Revenue Code, or the Code, and is administered by the Company’s board of directors and the compensation committee of the board of directors. The number of shares of common stock initially reserved for issuance under the 2015 ESPP was 720,000 shares with an automatic annual increase to the shares issuable under the 2015 ESPP equal to the lower of (i) 1% of the total number of shares of common stock outstanding on December 31 of the preceding calendar year, or (ii) a lower number determined by the board of directors. There was no annual increase of shares issuable under the 2015 ESPP on January 1, 2020. The Company had 1,527,421 shares available for future issuance under the 2015 ESPP as of June 30, 2020. The following table summarizes the assumptions used in the Black-Scholes option-pricing model to determine fair value of the Company’s common shares to be issued under the 2015 ESPP: Six Months Ended June 30, 2020 2019 Expected term (in years) 0.5 0.5 Volatility 127.5% 58.9% Risk-free interest rate 0.15% 2.43% Dividend yield —% —% Stock-based Compensation Expense Total stock-based compensation expense recognized for employees and non-employees was as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2020 2019 2020 2019 Research and development $ 1,363 $ 1,713 $ 2,226 $ 3,746 General and administrative 1,665 1,623 2,837 3,293 Total stock-based compensation expense $ 3,028 $ 3,336 $ 5,063 $ 7,039 In determining the fair value of the stock-based awards, the Company uses the Black-Scholes option-pricing model and assumptions discussed below. Each of these inputs is subjective and generally requires significant judgment. Fair Value of Common Stock — Since the Company’s IPO, the Company has used the market closing price of its common stock as reported on the Nasdaq Global Select Market. Expected Term —The Company’s expected term represents the period that the Company’s stock-based awards are expected to be outstanding and is determined using the simplified method (based on the mid-point between the vesting date and the end of the contractual term for employee options). The Company uses the contractual term to determine the non-employee award fair value at the grant date. Expected Volatility —The Company’s expected volatility is based on the historical volatility of the Company’s common stock price since its IPO in 2015. Risk-Free Interest Rate —The risk-free interest rate is based on the U.S. Treasury zero coupon issues in effect at the time of grant for periods corresponding with the expected term of option. Expected Dividend —The Company has never paid dividends on its common stock and has no plans to pay dividends on its common stock. Therefore, the Company used an expected dividend yield of zero. The fair value of stock option awards granted was estimated at the date of grant using a Black-Scholes option-pricing model with the following assumptions: Six Months Ended June 30, 2020 2019 Expected term (in years) 6.2 5.3 - 9.7 Volatility 75.0 - 79.7% 67.2 - 70.8% Risk-free interest rate 0.45 - 1.34% 1.96 - 3.19% Dividend yield —% —%

Restructuring and Related Expen

Restructuring and Related Expense	6 Months Ended
	Jun. 30, 2020
Restructuring And Related Activities [Abstract]
Restructuring and Related Expense	10. Restructuring and Related Expense In January 2020, the Company’s Board of Directors approved a restructuring to further extend the Company’s operating capital and align personnel towards executing the clinical development strategy. As of June 30, 2020, the Company reduced its workforce by 27 employees (approximately 28% of total employees) and intends to reduce its workforce by an additional 11 employees in the remainder of the year under the restructuring plan. Additionally, in June 2020, the Company closed its European site in Oss, the Netherlands. As of June 30, 2020, the Company estimates that it will incur aggregate charges of approximately $6.8 million, including $2.4 million in one-time severance and employee termination related costs, approximately $4.1 million in one-time retention costs and relocation costs of approximately $0.3 million. During the three and six months ended June 30, 2020, the Company accrued approximately $2.0 million and $5.2 million, respectively, of restructuring compensation and paid approximately $1.5 million and $2.5 million, respectively, of restructuring compensation. As of June 30, 2020, the Company has a remaining restructuring compensation reserve balance of approximately $2.7 million. The restructuring is expected to be substantially complete by the end of the third quarter of 2020. The restructuring plan includes the closure of the European site leased facility as of June 30, 2020. As a result, the Company fully impaired the European site’s property and equipment, consisting of lab equipment, computer and office equipment, furniture, and leasehold improvements, during the six months ended June 30, 2020. Additionally, the Company accelerated the amortization of the ROU asset associated with the leased facility so that the ROU asset will be fully amortized by June 30, 2020 rather than by December 31, 2020, the expiration of the Oss lease. For the three and six months ended June 30, 2020, the Company recorded an additional ROU asset amortization expense of $0.1 million and $0.2 million, respectively. On June 10, 2020, the Company terminated its lease agreement for the European site’s facility and will continue to pay the lease payments until December 31, 2020. The Company will be reimbursed for rent and fees paid from the termination date until December 31, 2020, if the landlord enters into a new lease agreement with a new tenant. Restructuring and related expense consist of the following (in thousands): Three Months Ended Six Months Ended June 30, 2020 June 30, 2020 Restructuring compensation $ 2,046 $ 5,152 Impairment of property and equipment — 1,202 Total restructuring and related expense $ 2,046 $ 6,354 For the three and six months ended June 30, 2019 in the consolidated statement of operations, the Company reclassified $0.4 million and $3.4 million, respectively, of restructuring and related expense associated with the January 2019 strategic reset from research and development and general and administrative to restructuring and related expense to be consistent with the presentation of the June 30, 2020 condensed consolidated financial statements.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2020
Income Tax Disclosure [Abstract]
Income Taxes	11. Income Taxes On March 27, 2020, the Coronavirus Aid, Relief, and Economic Security Act, or the CARES Act, was enacted in response to the COVID-19 global pandemic. The CARES Act, among other things, permits certain net operating losses, or NOLs, to be carried back for the preceding five taxable years to offset 100% of taxable income. Income tax benefit for the six months ended June 30, 2020 and 2019 was approximately $5.7 million and $0.1 million, respectively. The income tax benefit recorded for the six months ended June 30, 2020 was primarily related to the tax refund due to the carryback of NOLs and AMT credit refund. The income tax benefit for the six months ended on June 30, 2019 was primarily related to the foreign deferred tax benefit from the amortization of intangibles. The Company’s policy is to recognize interest and penalties related to unrecognized tax benefits in income tax expense. The Company files income tax returns in the United States and Netherlands. The federal and state income tax returns are open under the statute of limitations subject to tax examinations for the tax years ended December 31, 2016 through December 31, 2018. To the extent the Company has tax attribute carryforwards, the tax years in which the attribute was generated may still be adjusted upon examination by the IRS or state tax authorities to the extent utilized in a future period. For the Netherlands, the tax administration can impose an additional assessment within five years from the year in which the tax debt originated.

Net Loss Per Common Share

Net Loss Per Common Share	6 Months Ended
	Jun. 30, 2020
Earnings Per Share [Abstract]
Net Loss Per Common Share	12. Net Loss per Common Share Since the Company was in a loss position for all periods presented, diluted net loss per common share is the same as basic net loss per common share for all periods presented as the inclusion of all potential common shares outstanding would have been anti-dilutive. Potentially dilutive securities that were not included in the diluted per common share calculations because they would be anti-dilutive were as follows: Three Months Ended June 30, Six Months Ended June 30, 2020 2019 2020 2019 Options to purchase common stock 11,317,276 10,797,308 11,317,276 10,797,308 Restricted stock units 526,995 1,290,260 526,995 1,290,260 Common stock committed under ESPP 65,921 180,471 65,921 180,471 Common stock warrants 50,162 61,717 50,162 61,717 Total 11,960,354 12,329,756 11,960,354 12,329,756

Basis of Presentation, Use of_2

Basis of Presentation, Use of Estimates and Recent Accounting Pronouncements (Policies)	6 Months Ended
	Jun. 30, 2020
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles, or U.S. GAAP, and follow the requirements of the Securities and Exchange Commission, or the SEC, for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by U.S. GAAP have been condensed or omitted, and accordingly the unaudited condensed consolidated financial statements do not include all of the information and notes required by U.S. GAAP for complete financial statements. These financial statements have been prepared on the same basis as the Company’s annual financial statements and, in the opinion of management, reflect all adjustments (consisting only of normal recurring adjustments) that are necessary for a fair presentation of the Company’s financial information. The results of operations for the three and six months ended June 30, 2020 are not necessarily indicative of the results to be expected for the year ending December 31, 2020 or for any other interim period or for any other future year. The accompanying condensed consolidated financial statements and related financial information should be read in conjunction with the audited consolidated financial statements and the related notes thereto for the year ended December 31, 2019 included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2019 filed with the SEC on March 9, 2020. The condensed consolidated financial statements include the accounts of Aduro Biotech, Inc. and its wholly-owned subsidiaries. All intercompany transactions and balances have been eliminated.
Use of Estimates	Use of Estimates The preparation of 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 and reported amounts of revenue and expenses in the financial statements and accompanying notes. On an ongoing basis, management evaluates its estimates, including those related to revenue recognition, clinical trial accruals, contingent consideration, income taxes, right-of-use assets, lease obligations, stock-based compensation, and valuation of intangibles and goodwill. Management bases its estimates on historical experience and on various other market-specific and relevant assumptions that management believes to be reasonable under the circumstances. Actual results could differ from these estimates.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In June 2016, the Financial Accounting Standards Board, or FASB, issued Accounting Standard Update, or ASU, No. 2016-13 – Financial Instruments—Credit Losses (Topic 326). The standard changes how entities will measure credit losses for most financial assets and certain other instruments that are not measured at fair value through net income. Financial assets measured at amortized cost will be presented at the net amount expected to be collected by using an allowance for credit losses. In April 2019, the FASB issued ASU No. 2019-04, Codification Improvements to Topic 326, Financial Instruments – Credit Losses, Topic 815, Derivatives and Hedging, and Topic 825, Financial Instruments, which clarifies and corrects certain unintended applications of the guidance contained in each of the amended Topics. Additionally, in May 2019, the FASB issued ASU No. 2019-05, Financial Instruments – Credit Losses (Topic 326), which provides an option to irrevocably elect to measure certain individual financial assets at fair value instead of amortized cost. In November 2019, the FASB issued ASU No. 2019-10, Financial Instruments – Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842), which defers the effective date for ASU No. 2016-13 for smaller reporting companies to fiscal years beginning after December 15, 2022, including interim periods within those fiscal years. Early adoption is permitted for all periods beginning after December 15, 2018. The Company does not plan to early adopt and is currently in the process of evaluating the impact the standard will have on its consolidated financial statements. In December 2019, the FASB issued ASU No. 2019-12 – Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes (ASU 2019-12). The standard update simplifies the accounting for income taxes by removing certain exceptions to the general principles in ASC 740 and also improves consistent application by clarifying and amending existing guidance. The standard is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020. Early adoption is permitted. The Company has evaluated the impact of this guidance and has concluded that adoption of the standard will not have a material impact on its consolidated financial statements.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements In August 2018, the FASB issued ASU No. 2018-13 – Fair Value Measurement (Topic 820): Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement. The standard eliminates certain disclosure requirements for fair value measurements for all entities, requires public entities to disclose certain new information, and modifies some disclosure requirements. The new standard is effective for fiscal years and interim periods beginning after December 15, 2019. The Company adopted the new standard on January 1, 2020. As the result of the adoption the Company is no longer required to disclose (1) the amount of and the reasons for transfers between Level 1 and Level 2 of the fair value hierarchy, (2) the policy for timing of transfers between levels, and (3) the valuation process for Level 3 fair value measurements. Additionally, the Company is required to disclose (1) the changes in unrealized gains and losses for the period included in other comprehensive income (loss) for recurring Level 3 fair value measurements held at the end of the reporting period and (2) the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. Refer to Note 3 “Fair Value Measurements” for the newly required disclosures resulting from the adoption of this standard.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2020
Fair Value Disclosures [Abstract]
Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis	The following table sets forth the Company’s financial instruments that were measured at fair value on a recurring basis by level within the fair value hierarchy (in thousands): June 30, 2020 Level 1 Level 2 Level 3 Total Financial Assets: Money market funds $ 30,913 $ — $ — $ 30,913 U.S. government and agency securities — 66,209 — 66,209 Corporate debt securities — 17,702 — 17,702 Commercial paper — 67,304 — 67,304 Total $ 30,913 $ 151,215 $ — $ 182,128 Financial Liabilities: Contingent consideration related to acquisition $ — $ — $ 2,013 $ 2,013 Total $ — $ — $ 2,013 $ 2,013 December 31, 2019 Level 1 Level 2 Level 3 Total Financial Assets: Money market funds $ 39,994 $ — $ — $ 39,994 U.S. government and agency securities — 43,333 — 43,333 Corporate debt securities — 54,590 — 54,590 Commercial paper — 67,536 — 67,536 Total $ 39,994 $ 165,459 $ — $ 205,453 Financial Liabilities: Contingent consideration related to acquisition $ — $ — $ 1,051 $ 1,051 Total $ — $ — $ 1,051 $ 1,051
Schedule of Changes in Fair Value of Liability for Contingent Consideration	Changes in the fair value of the liability for contingent consideration will be recognized in the consolidated statement of operations until settlement. Unobservable Input Probability of attaining milestone 18.8 % Period of time to achieve milestone (in years) 7.5 Discount rate 10.0 %
Summary of Changes in Fair Value of Level 3 Financial Liabilities	The following table sets forth a summary of the changes in the fair value of the Company’s Level 3 financial liabilities (in thousands): Contingent Consideration Balance at December 31, 2019 $ 1,051 Net change in fair value upon remeasurement 943 Foreign currency impact on contingent consideration 19 Balance at June 30, 2020 $ 2,013
Summary of Estimated Value of Cash, Cash Equivalents and Marketable Securities and Gross Unrealized Holding Gains and Losses	The following tables summarize the estimated value of the Company’s cash, cash equivalents and marketable securities and the gross unrealized holding gains and losses (in thousands): June 30, 2020 Amortized cost Unrealized gains Unrealized losses Estimated Fair Value Cash and cash equivalents: Cash $ 3,998 $ — $ — $ 3,998 Money market funds 30,913 — — 30,913 Commercial paper 29,791 2 (1 ) 29,792 U.S. government and agency securities 6,400 — — 6,400 Total cash and cash equivalents $ 71,102 $ 2 $ (1 ) $ 71,103 Marketable securities: U.S. government and agency securities $ 59,800 $ 20 $ (11 ) $ 59,809 Corporate debt securities 17,639 63 — 17,702 Commercial paper 37,493 20 (1 ) 37,512 Total marketable securities $ 114,932 $ 103 $ (12 ) $ 115,023 December 31, 2019 Amortized cost Unrealized gains Unrealized losses Estimated Fair Value Cash and cash equivalents: Cash $ 8,149 $ — $ — $ 8,149 Money market funds 39,994 — — 39,994 Commercial paper 11,482 — (1 ) 11,481 Total cash and cash equivalents $ 59,625 $ — $ (1 ) $ 59,624 Marketable securities: U.S. government and agency securities $ 43,295 $ 40 $ (2 ) $ 43,333 Corporate debt securities 54,563 33 (6 ) 54,590 Commercial paper 56,055 7 (7 ) 56,055 Total marketable securities $ 153,913 $ 80 $ (15 ) $ 153,978
Summary of Amortized Cost and Estimated Fair Value of Available-for-Sale Marketable Securities by Contractual Maturity	The amortized cost and estimated fair value of the Company’s available-for-sale marketable securities by contractual maturity are summarized below as of June 30, 2020 (in thousands): Amortized cost Unrealized gains Unrealized losses Estimated Fair Mature in one year or less $ 99,936 $ 102 $ (10 ) $ 100,028 Mature after one year through two years 14,996 1 (2 ) 14,995 Total available-for-sale marketable securities $ 114,932 $ 103 $ (12 ) $ 115,023

Balance Sheet Components (Table

Balance Sheet Components (Tables)	6 Months Ended
	Jun. 30, 2020
Balance Sheet Related Disclosures [Abstract]
Summary of Property and Equipment, Net	Property and equipment, net consisted of the following (in thousands): June 30, December 31, 2020 2019 Leasehold improvements $ 27,084 $ 27,288 Lab equipment 6,046 8,817 Computer and office equipment 2,146 2,334 Furniture 1,427 1,590 Construction in progress 122 190 Total property and equipment 36,825 40,219 Less: accumulated depreciation (15,119 ) (15,531 ) Property and equipment, net $ 21,706 $ 24,688
Accrued Expenses and Other Liabilities	Accrued expenses and other liabilities consisted of the following (in thousands): June 30, December 31, 2020 2019 Compensation and related benefits $ 4,539 $ 3,677 Professional and consulting services 3,410 2,845 Accrued research expense 895 890 Accrued purchases of property and equipment 23 31 Other 806 738 Total accrued expenses and other liabilities $ 9,673 $ 8,181

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	6 Months Ended
	Jun. 30, 2020
Goodwill And Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The gross carrying amount of goodwill was as follows (in thousands): Balance at December 31, 2019 $ 8,167 Foreign currency translation adjustment 10 Balance at June 30, 2020 $ 8,177
Schedule of Intangible Assets	The gross carrying amounts and net book value of intangible assets were as follows (in thousands): June 30, 2020 Gross Amount Accumulated Amortization Net Book Value Intangible assets with finite lives: License agreement $ 11,104 $ 2,591 $ 8,513 Total intangible assets with finite lives 11,104 2,591 8,513 Acquired IPR&D assets 10,210 — 10,210 Total intangible assets $ 21,314 $ 2,591 $ 18,723 December 31, 2019 Gross Amount Impairment (1) Accumulated Amortization Net Book Value Intangible assets with finite lives: License agreement $ 11,091 $ — $ 2,311 $ 8,780 Total intangible assets with finite lives 11,091 — 2,311 8,780 Acquired IPR&D assets 15,297 5,099 — 10,198 Total intangible assets $ 26,388 $ 5,099 $ 2,311 $ 18,978 (1) The amount includes effects of foreign currency exchange rates.
Schedule of Finite-Lived Intangible Assets Estimated Future Amortization Expense	Based on finite-lived intangible assets recorded as of June 30, 2020, the estimated future amortization expense for the next five years is as follows (in thousands): Year Ending December 31, Estimated Amortization Expense 2020 (remaining six months) $ 278 2021 555 2022 555 2023 555 2024 555 2025 555

Commitments and Contingencies (

Commitments and Contingencies (Tables)	6 Months Ended
	Jun. 30, 2020
Commitments And Contingencies Disclosure [Abstract]
Schedule of Maturity of Operating Lease Liabilities	The maturity of the Company’s operating lease liabilities as of June 30, 2020 is as follows (in thousands): Undiscounted Lease Payments Amounts 2020 (remaining six months) $ 2,862 2021 5,332 2022 5,460 2023 5,569 2024 5,681 Thereafter 30,155 Total undiscounted lease payments 55,059 Present value adjustment 22,463 Total net lease liability $ 32,596 Net lease liability - current $ 1,741 Net lease liability - non-current 30,855 Total net lease liability $ 32,596
Schedule of Supplemental Disclosure Cash Flow Related to Operating Leases	The following information represents supplemental disclosure for the condensed consolidated statement of cash flows related to operating leases (in thousands): Six months ended June 30, 2020 2019 Cash flows from operating activities Cash paid for amounts included in the measurement of lease liabilities $ 2,798 $ 2,727
Schedule of Additional Information Related to Operating Leases	The following summarizes additional information related to operating leases: June 30, 2020 June 30, 2019 Weighted-average remaining lease terms (in years) Operating leases 9.4 10.3 Weighted-average discount rate Operating leases 12% 12%

Common Stock (Tables)

Common Stock (Tables)	6 Months Ended
	Jun. 30, 2020
Equity [Abstract]
Schedule of Common Share Reserved for Future Issuance	The Company had reserved shares of common stock for future issuance as follows: June 30, 2020 Options issued and outstanding 11,317,276 Shares available for future stock option grants 10,941,502 Restricted stock units 526,995 Common stock warrants 50,162 Total 22,835,935

Equity Incentive Plans (Tables)

Equity Incentive Plans (Tables)	6 Months Ended
	Jun. 30, 2020
Summary of Stock Option Plan Activity	Stock Options The following table summarizes stock option activity for the six months ended June 30, 2020: Options Outstanding Shares Available for Grant Number of Shares Underlying Options Weighted- Average Exercise Price Aggregate Intrinsic Value (In thousands) Balance—December 31, 2019 8,751,436 10,297,444 $ 5.49 $ 680 Authorized 3,229,427 — RSUs forfeited, net 83,007 — Granted (3,136,000 ) 3,136,000 3.14 Exercised — (91,460 ) 0.91 Canceled 2,013,632 (1) (2,024,708 ) 5.87 Balance—June 30, 2020 10,941,502 11,317,276 $ 4.81 $ 3,671 Options exercisable—June 30, 2020 6,264,788 $ 5.82 $ 3,369 Options vested and expected to vest—June 30, 2020 10,204,429 $ 4.97 $ 3,608 (1)
Summary of Restricted Stock Unit or RSU Activity	The following table summarizes RSU activity for the six months ended June 30, 2020: RSUs Outstanding Number of Restricted Units Weighted- Average Grant Date Fair Share Balance—December 31, 2019 798,943 $ 7.40 Granted 109,124 3.37 Vested (188,941 ) 3.99 Forfeited (192,131 ) 8.34 Balance—June 30, 2020 526,995 $ 7.45
Summary of Stock-Based Compensation Expense Recognized for Employees and Non-Employees	Total stock-based compensation expense recognized for employees and non-employees was as follows (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2020 2019 2020 2019 Research and development $ 1,363 $ 1,713 $ 2,226 $ 3,746 General and administrative 1,665 1,623 2,837 3,293 Total stock-based compensation expense $ 3,028 $ 3,336 $ 5,063 $ 7,039
Schedule of Black-Scholes Option-Pricing Model	The fair value of stock option awards granted was estimated at the date of grant using a Black-Scholes option-pricing model with the following assumptions: Six Months Ended June 30, 2020 2019 Expected term (in years) 6.2 5.3 - 9.7 Volatility 75.0 - 79.7% 67.2 - 70.8% Risk-free interest rate 0.45 - 1.34% 1.96 - 3.19% Dividend yield —% —%
2015 ESPP
Schedule of Black-Scholes Option-Pricing Model	The following table summarizes the assumptions used in the Black-Scholes option-pricing model to determine fair value of the Company’s common shares to be issued under the 2015 ESPP: Six Months Ended June 30, 2020 2019 Expected term (in years) 0.5 0.5 Volatility 127.5% 58.9% Risk-free interest rate 0.15% 2.43% Dividend yield —% —%

Restructuring and Related Exp_2

Restructuring and Related Expense (Tables)	6 Months Ended
	Jun. 30, 2020
Restructuring And Related Activities [Abstract]
Schedule of Restructuring Expenses	Restructuring and related expense consist of the following (in thousands): Three Months Ended Six Months Ended June 30, 2020 June 30, 2020 Restructuring compensation $ 2,046 $ 5,152 Impairment of property and equipment — 1,202 Total restructuring and related expense $ 2,046 $ 6,354

Net Loss per Common Share (Tabl

Net Loss per Common Share (Tables)	6 Months Ended
	Jun. 30, 2020
Earnings Per Share [Abstract]
Schedule of Potentially Dilutive Securities not Included in Calculation of Diluted Per Common Share	Potentially dilutive securities that were not included in the diluted per common share calculations because they would be anti-dilutive were as follows: Three Months Ended June 30, Six Months Ended June 30, 2020 2019 2020 2019 Options to purchase common stock 11,317,276 10,797,308 11,317,276 10,797,308 Restricted stock units 526,995 1,290,260 526,995 1,290,260 Common stock committed under ESPP 65,921 180,471 65,921 180,471 Common stock warrants 50,162 61,717 50,162 61,717 Total 11,960,354 12,329,756 11,960,354 12,329,756

Organization and Nature of Bu_2

Organization and Nature of Business - Additional Information (Details)	6 Months Ended
	Jun. 30, 2020Segment
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Number of business segments	1

Fair Value Measurements - Finan

Fair Value Measurements - Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Financial Assets:
Financial Assets, fair value	$ 182,128	$ 205,453
Financial Liabilities:
Financial Liabilities, fair value	2,013	1,051
Contingent Consideration Related To Acquisition
Financial Liabilities:
Financial Liabilities, fair value	2,013	1,051
Money Market Funds
Financial Assets:
Financial Assets, fair value	30,913	39,994
U.S. Government and Agency Securities
Financial Assets:
Financial Assets, fair value	66,209	43,333
Corporate Debt Securities
Financial Assets:
Financial Assets, fair value	17,702	54,590
Commercial Paper
Financial Assets:
Financial Assets, fair value	67,304	67,536
Level 1
Financial Assets:
Financial Assets, fair value	30,913	39,994
Level 1 | Money Market Funds
Financial Assets:
Financial Assets, fair value	30,913	39,994
Level 2
Financial Assets:
Financial Assets, fair value	151,215	165,459
Level 2 | U.S. Government and Agency Securities
Financial Assets:
Financial Assets, fair value	66,209	43,333
Level 2 | Corporate Debt Securities
Financial Assets:
Financial Assets, fair value	17,702	54,590
Level 2 | Commercial Paper
Financial Assets:
Financial Assets, fair value	67,304	67,536
Level 3
Financial Liabilities:
Financial Liabilities, fair value	2,013	1,051
Level 3 | Contingent Consideration Related To Acquisition
Financial Liabilities:
Financial Liabilities, fair value	$ 2,013	$ 1,051

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Changes in Fair Value of Liability for Contingent Consideration (Details)	6 Months Ended
	Jun. 30, 2020
Probability of Attaining Milestone
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Contingent consideration liability, measurement input	0.188
Period of Time to Achieve Milestone
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Period of time to achieve milestone (in years)	7 years 6 months
Discount Rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Contingent consideration liability, measurement input	0.100

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - Fair Value, Measurements, Nonrecurring - USD ($)	Jun. 30, 2020	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Financial assets measured at fair value on a nonrecurring basis	$ 0	$ 0
Financial liabilities measured at fair value on a nonrecurring basis	$ 0	$ 0

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Changes in Fair Value of Level 3 Financial Liabilities (Details) - Contingent Consideration $ in Thousands	6 Months Ended
	Jun. 30, 2020USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Beginning balance	$ 1,051
Net change in fair value upon remeasurement	943
Foreign currency impact on contingent consideration	19
Ending balance	$ 2,013

Fair Value Measurements - Sum_2

Fair Value Measurements - Summary of Estimated Value of Cash, Cash Equivalents and Marketable Securities and Gross Unrealized Holding Gains and Losses (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and cash equivalents, Amortized cost	$ 71,102	$ 59,625
Cash and cash equivalents, Unrealized gains	2
Cash and cash equivalents, Unrealized losses	(1)	(1)
Cash and cash equivalents, Estimated Fair Value	71,103	59,624
Marketable securities, Amortized cost	114,932	153,913
Marketable securities, Unrealized gains	103	80
Marketable securities, Unrealized losses	(12)	(15)
Marketable securities, Estimated Fair Value	115,023	153,978
Cash
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and cash equivalents, Amortized cost	3,998	8,149
Cash and cash equivalents, Estimated Fair Value	3,998	8,149
Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and cash equivalents, Amortized cost	30,913	39,994
Cash and cash equivalents, Estimated Fair Value	30,913	39,994
Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and cash equivalents, Amortized cost	29,791	11,482
Cash and cash equivalents, Unrealized gains	2
Cash and cash equivalents, Unrealized losses	(1)	(1)
Cash and cash equivalents, Estimated Fair Value	29,792	11,481
U.S. Government and Agency Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash and cash equivalents, Amortized cost	6,400
Cash and cash equivalents, Estimated Fair Value	6,400
Marketable securities, Amortized cost	59,800	43,295
Marketable securities, Unrealized gains	20	40
Marketable securities, Unrealized losses	(11)	(2)
Marketable securities, Estimated Fair Value	59,809	43,333
Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, Amortized cost	17,639	54,563
Marketable securities, Unrealized gains	63	33
Marketable securities, Unrealized losses		(6)
Marketable securities, Estimated Fair Value	17,702	54,590
Commercial paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities, Amortized cost	37,493	56,055
Marketable securities, Unrealized gains	20	7
Marketable securities, Unrealized losses	(1)	(7)
Marketable securities, Estimated Fair Value	$ 37,512	$ 56,055

Fair Value Measurements - Sum_3

Fair Value Measurements - Summary of Amortized Cost and Estimated Fair Value of Available-for-Sale Marketable Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Mature in one year or less, Amortized cost	$ 99,936
Mature after one year through two years, Amortized cost	14,996
Marketable securities, Amortized cost	114,932	$ 153,913
Mature in one year or less, Unrealized gains	102
Mature after one year through two years, Unrealized gains	1
Total available-for-sale marketable securities, Unrealized gains	103	80
Mature in one year or less, Unrealized losses	(10)
Mature after one year through two years, Unrealized losses	(2)
Total available-for-sale marketable securities, Unrealized losses	(12)	(15)
Mature in one year or less, Estimated Fair Value	100,028
Mature after one year through two years, Estimated Fair Value	14,995
Total available-for-sale marketable securities, Estimated Fair Value	$ 115,023	$ 153,978

Balance Sheet Components - Summ

Balance Sheet Components - Summary of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 36,825	$ 40,219
Less: accumulated depreciation	(15,119)	(15,531)
Property and equipment, net	21,706	24,688
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	27,084	27,288
Lab Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	6,046	8,817
Computer and Office Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	2,146	2,334
Furniture
Property Plant And Equipment [Line Items]
Property and equipment, gross	1,427	1,590
Construction in Progress
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 122	$ 190

Balance Sheet Components - Addi

Balance Sheet Components - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Balance Sheet Related Disclosures [Abstract]
Depreciation	$ 800	$ 1,100	$ 1,837	$ 2,175

Balance Sheet Components - Su_2

Balance Sheet Components - Summary of Accrued Expenses and Other Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Payables And Accruals [Abstract]
Compensation and related benefits	$ 4,539	$ 3,677
Professional and consulting services	3,410	2,845
Accrued research expense	895	890
Accrued purchases of property and equipment	23	31
Other	806	738
Total accrued expenses and other liabilities	$ 9,673	$ 8,181

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Schedule of Goodwill (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2020USD ($)
Goodwill And Intangible Assets Disclosure [Abstract]
Beginning Balance	$ 8,167
Foreign currency translation adjustment	10
Ending Balance	$ 8,177

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Additional Information (Details) - USD ($)	3 Months Ended			6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Goodwill And Intangible Assets [Line Items]
Impairment of goodwill		$ 0
Amortization of intangible assets	$ 136,000		$ 139,000	$ 272,000	$ 279,000
Acquired IPR&D intangible assets
Goodwill And Intangible Assets [Line Items]
Intangible assets, impairment				$ 0
Novartis
Goodwill And Intangible Assets [Line Items]
Intangible assets, amortization period				20 years

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Schedule of Intangible Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Schedule Of Finite And Indefinite Lived Intangible Assets [Line Items]
Finite Lived Intangible Assets, Gross Carrying Amount	$ 11,104	$ 11,091
Finite Lived Intangible Assets, Accumulated Amortization	2,591	2,311
Finite Lived Intangible Assets, Net Book Value	8,513	8,780
Indefinite-Lived Intangible Assets, Impairment		5,099
Intangible Assets, Gross Carrying Amount	21,314	26,388
Intangible assets, Net Book Value	18,723	18,978
License agreement
Schedule Of Finite And Indefinite Lived Intangible Assets [Line Items]
Finite Lived Intangible Assets, Gross Carrying Amount	11,104	11,091
Finite Lived Intangible Assets, Accumulated Amortization	2,591	2,311
Finite Lived Intangible Assets, Net Book Value	8,513	8,780
Acquired IPR&D assets
Schedule Of Finite And Indefinite Lived Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets, Gross Carrying Amount	10,210	15,297
Indefinite-Lived Intangible Assets, Impairment		5,099
Indefinite-Lived Intangible Assets, Net Book Value	$ 10,210	$ 10,198

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets - Schedule of Finite-Lived Intangible Assets Estimated Future Amortization Expense (Details) $ in Thousands	Jun. 30, 2020USD ($)
Goodwill And Intangible Assets Disclosure [Abstract]
2020 (remaining six months)	$ 278
2021	555
2022	555
2023	555
2024	555
2025	$ 555

Collaboration Agreements - Addi

Collaboration Agreements - Additional Information (Details) - USD ($)	1 Months Ended	3 Months Ended						6 Months Ended		12 Months Ended	63 Months Ended
	Apr. 30, 2015	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Mar. 31, 2018	Jun. 30, 2016	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2017	Jun. 30, 2020
Novartis Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Payments received under collaboration agreement	$ 200,000,000						$ 35,000,000				$ 2,100,000
Novartis share of joint development costs								38.00%
Period after first commercial sale of product on which Novartis' royalty obligation run on a country to country basis								12 years
Remaining performance obligations		$ 237,100,000						$ 237,100,000			237,100,000
Revenue recognized		3,900,000		$ 1,900,000				5,700,000	$ 4,400,000
Deferred revenue		163,300,000						$ 163,300,000			163,300,000
Novartis Agreement | United States
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaborative arrangement profit share percentage								50.00%
Novartis Agreement | European Countries and Japan
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaborative arrangement profit share percentage								45.00%
Novartis Agreement | United States, Specified European Countries and /or Japan
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaborative Agreement, Obligations								With respect to the United States, specified European countries and/or Japan, the Company may elect for such region to either reduce by 50% or to eliminate in full the Company’s development and commercialization cost sharing obligation. If the Company elects to reduce its cost sharing percentage by 50% in any such region, then its profit share in such region will also be reduced by 50%. If the Company elects to eliminate its development cost sharing obligation, then such region will be removed from the profit share, and instead Novartis will owe the Company royalties on any net sales of product for such region, as described above.
Reduction percentage of development cost share								50.00%
Reduction percentage of profit share								50.00%
Novartis Agreement | Novartis
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Novartis share of joint development costs								62.00%
Collaborative arrangement profit share percentage								50.00%
Novartis Agreement | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Development milestones amount eligible to receive								$ 215,000,000
Regulatory approval milestones amount eligible to receive								250,000,000
Lilly Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Payments received under collaboration agreement					$ 12,000,000			12,000,000
Revenue recognized		1,700,000		$ 3,000,000				3,900,000	$ 4,400,000
Deferred revenue		2,900,000						$ 2,900,000			2,900,000
Royalty payments receivable terms								Lilly is also obligated to pay the Company tiered royalty payments at percentages in the single to low-double digits based on annual net sales of the licensed products. Lilly must pay such royalties on a product-by-product and country-by-country basis until the latest to occur of (i) the expiration of the last-to-expire valid claim of certain patents, (ii) the expiration of the data exclusivity period in such country or (iii) a specified anniversary of the first commercial sale of such product in such country.
Lilly Agreement | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone amount eligible to receive for products or product candidates								$ 620,000,000
Merck License Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Payments received under collaboration agreement			$ 10,000,000			$ 3,000,000				$ 2,000,000
Remaining performance obligations		0				$ 0		0		$ 0	$ 0
Revenue recognized		$ 0
Milestone payment								10,000,000
Merck License Agreement | Maximum | Product Candidate
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone amount eligible to receive for products or product candidates								297,000,000
Merck License Agreement | Maximum | Product
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Milestone amount eligible to receive for products or product candidates								$ 135,000,000

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020USD ($)ft²LeaseFacility	Jun. 30, 2019USD ($)	Jun. 30, 2020USD ($)ft²LeaseFacility	Jun. 30, 2019USD ($)	Dec. 31, 2016USD ($)
Operating Leased Assets [Line Items]
Operating lease, remaining lease term	9 years 4 months 24 days	10 years 3 months 18 days	9 years 4 months 24 days	10 years 3 months 18 days
Security deposit	$ 0.5		$ 0.5
Operating leases rent expense	1.4	$ 1.2	2.7	$ 2.5
Operating Leases variable lease payments	$ 0.3	0.3	$ 0.7	0.6
Bank Of America Merrill Lynch
Operating Leased Assets [Line Items]
Letter of credit outstanding					$ 0.5
Berkeley, California
Operating Leased Assets [Line Items]
Operating lease, remaining lease term	10 years		10 years
Number of lease facility | LeaseFacility	1		1
Berkeley, California | Sublease
Operating Leased Assets [Line Items]
Total square footage of leased property | ft²	26,552		26,552
Lease expiration date			Feb. 28, 2021
Sublease Income	$ 0.4	$ 0.4	$ 0.7	$ 0.8
Oss, Netherlands
Operating Leased Assets [Line Items]
Operating leases term of expiration			2020-12
Number of lease facility | LeaseFacility	1		1

Commitments and Contingencies_2

Commitments and Contingencies - Schedule of Maturity of Company's Operating Lease Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
2020 (remaining six months)	$ 2,862
2021	5,332
2022	5,460
2023	5,569
2024	5,681
Thereafter	30,155
Total undiscounted lease payments	55,059
Present value adjustment	22,463
Total net lease liability	32,596
Net lease liability - current	1,741	$ 1,803
Net lease liability - non-current	30,855	$ 31,636
Total net lease liability	$ 32,596

Commitments and Contingencies_3

Commitments and Contingencies - Schedule of Supplemental Disclosure Cash Flow Related to Operating Leases (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities
Cash paid for amounts included in the measurement of lease liabilities	$ 2,798	$ 2,727

Commitments and Contingencies_4

Commitments and Contingencies - Schedule of Additional Information Related to Operating Leases (Details)	Jun. 30, 2020	Jun. 30, 2019
Weighted-average remaining lease terms (in years)
Operating leases	9 years 4 months 24 days	10 years 3 months 18 days
Weighted-average discount rate
Operating leases	12.00%	12.00%

Common Stock - Schedule of Comm

Common Stock - Schedule of Common Share Reserved for Future Issuance (Details) - shares	Jun. 30, 2020	Dec. 31, 2019
Class Of Stock [Line Items]
Common stock, capital shares reserved for future issuance	22,835,935
Shares available for future stock option grants	10,941,502	8,751,436
Options Issued and Outstanding
Class Of Stock [Line Items]
Common stock, capital shares reserved for future issuance	11,317,276
Restricted Stock Units (RSUs)
Class Of Stock [Line Items]
Common stock, capital shares reserved for future issuance	526,995
Common Stock Warrants
Class Of Stock [Line Items]
Common stock, capital shares reserved for future issuance	50,162

Common Stock - Additional Infor

Common Stock - Additional Information (Details) - At-the-Market Offering - 2017 Sales Agreement - Cowen and Company, LLC - USD ($)	1 Months Ended	6 Months Ended	12 Months Ended
	Aug. 31, 2017	Jun. 30, 2020	Dec. 31, 2019
Class Of Stock [Line Items]
Commission on sales of common stock, percentage	3.00%
Issuance of common stock (in shares)		0	0
Aggregate offering available for issuance of common stock		$ 81,500,000
Agreement maturity date		Aug. 11, 2020
Maximum
Class Of Stock [Line Items]
Aggregate offering price from offer and sale of common stock	$ 100,000,000

Equity Incentive Plans - Additi

Equity Incentive Plans - Additional Information (Details) - USD ($) $ in Millions	Jan. 01, 2020	Feb. 28, 2015	Jun. 30, 2020	Dec. 31, 2019	Apr. 30, 2015
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares issuable increased during the period			3,229,427
Number of shares available for future grant			10,941,502	8,751,436
Number of options outstanding			11,317,276	10,297,444
Aggregate intrinsic value of options exercised			$ 0.1
Unrecognized compensation expense			$ 9
Weighted-average period of unrecognized compensation expense			2 years 10 months 24 days
Expected dividend yield			0.00%
Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average period of unrecognized compensation expense			1 year 9 months 18 days
Unrecognized stock-based compensation expense related to RSUs			$ 1.8
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of exercise price to fair market value common stock on grant date			100.00%
Stock option expiration period			10 years
2015 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock shares reserved for issuance					6,134,292
Percentage of shares issued on common stock outstanding			4.00%
Common Stock Issuance Description			shares issuable under the 2015 Plan to the lower of (i) 4% of the total number of shares of common stock outstanding on December 31 of the preceding calendar year, or (ii) a lower number determined by the board of directors.
Shares issuable increased during the period	3,229,427
Number of shares available for future grant			10,941,502
2009 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares issuable increased during the period		360,000
Number of options outstanding			2,691,784
2015 ESPP
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock shares reserved for issuance					720,000
Percentage of shares issued on common stock outstanding			1.00%
Common Stock Issuance Description			shares issuable under the 2015 ESPP equal to the lower of (i) 1% of the total number of shares of common stock outstanding on December 31 of the preceding calendar year, or (ii) a lower number determined by the board of directors.
Shares issuable increased during the period	0
Number of shares available for future grant			1,527,421
More Than 10% Voting Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option expiration period			5 years
More Than 10% Voting Shares | Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of exercise price to fair market value common stock on grant date			110.00%

Equity Incentive Plans - Summar

Equity Incentive Plans - Summary of Stock Option Activity (Details) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2020USD ($)$ / sharesshares	Dec. 31, 2019USD ($)
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Options Outstanding, Shares Available for Grant, Beginning balance	8,751,436
Options Outstanding, Shares Available for Grant, Authorized	3,229,427
Options Outstanding, Shares Available for Grant, RSUs forfeited, net	83,007
Options Outstanding, Shares Available for Grant, Granted	(3,136,000)
Options Outstanding, Shares Available for Grant, Canceled	2,013,632
Options Outstanding, Shares Available for Grant, Ending balance	10,941,502
Options Outstanding, Number of Shares Underlying Options, Beginning balance	10,297,444
Options Outstanding, Number of Shares Underlying Options, Granted	3,136,000
Options Outstanding, Number of Shares Underlying Options, Exercised	(91,460)
Options Outstanding, Number of Shares Underlying Options, Canceled	(2,024,708)
Options Outstanding, Number of Shares Underlying Options, Ending balance	11,317,276
Options Outstanding, Number of Shares Underlying Options, Options exercisable	6,264,788
Options Outstanding, Number of Shares Underlying Options, Options vested and expected to vest	10,204,429
Options Outstanding, Weighted-Average Exercise Price, Beginning balance | $ / shares	$ 5.49
Options Outstanding, Weighted-Average Exercise Price, Granted | $ / shares	3.14
Options Outstanding, Weighted-Average Exercise Price, Exercised | $ / shares	0.91
Options Outstanding, Weighted-Average Exercise Price, Canceled | $ / shares	5.87
Options Outstanding, Weighted-Average Exercise Price, Ending balance | $ / shares	4.81
Options Outstanding, Weighted-Average Exercise Price, Options exercisable | $ / shares	5.82
Options Outstanding, Weighted-Average Exercise Price, Options vested and expected to vest | $ / shares	$ 4.97
Options Outstanding, Aggregate Intrinsic Value, Balance | $	$ 3,671	$ 680
Options Outstanding, Aggregate Intrinsic Value, Options exercisable-March 31, 2019 | $	3,369
Options Outstanding, Aggregate Intrinsic Value, Options vested and expected to vest-March 31, 2019 | $	$ 3,608

Equity Incentive Plans - Summ_2

Equity Incentive Plans - Summary of Stock Option Activity (Parenthetical) (Details)	6 Months Ended
	Jun. 30, 2020shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of subject to canceled options excluded	11,076

Equity Incentive Plans - Summ_3

Equity Incentive Plans - Summary of Restricted Stock Unit or RSU Activity (Details) - Restricted Stock Units (RSUs)	6 Months Ended
	Jun. 30, 2020$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Restricted Stock Units, Beginning balance | shares	798,943
Number of Restricted Stock Units, Granted | shares	109,124
Number of Restricted Stock Units, Vested | shares	(188,941)
Number of Restricted Stock Units, Forfeited | shares	(192,131)
Number of Restricted Stock Units, Ending balance | shares	526,995
Weighted-Average Grant Date Fair Value Per Share, Beginning balance | $ / shares	$ 7.40
Weighted-Average Grant Date Fair Value Per Share, Granted | $ / shares	3.37
Weighted-Average Grant Date Fair Value Per Share, Vested | $ / shares	3.99
Weighted-Average Grant Date Fair Value Per Share, Forfeited | $ / shares	8.34
Weighted-Average Grant Date Fair Value Per Share, Ending balance | $ / shares	$ 7.45

Equity Incentive Plans - Schedu

Equity Incentive Plans - Schedule of Black-Scholes Option-Pricing Model (Details)	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	6 years 2 months 12 days
Volatility, Minimum	75.00%	67.20%
Volatility, Maximum	79.70%	70.80%
Risk-free interest rate, Minimum	0.45%	1.96%
Risk-free interest rate, Maximum	1.34%	3.19%
Dividend yield	0.00%
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)		5 years 3 months 18 days
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)		9 years 8 months 12 days
2015 ESPP
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	6 months	6 months
Volatility	127.50%	58.90%
Risk-free interest rate	0.15%	2.43%

Equity Incentive Plans - Summ_4

Equity Incentive Plans - Summary of Stock-Based Compensation Expense Recognized for Employees and Non-Employees (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 3,028	$ 3,336	$ 5,063	$ 7,039
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	1,363	1,713	2,226	3,746
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 1,665	$ 1,623	$ 2,837	$ 3,293

Restructuring Expense - Additio

Restructuring Expense - Additional Information (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020USD ($)	Jun. 30, 2019USD ($)	Dec. 31, 2020Employee	Jun. 30, 2020USD ($)Employee	Jun. 30, 2019USD ($)
Restructuring Cost And Reserve [Line Items]
Restructuring compensation	$ 2,046			$ 5,152
ROU asset, amortization expense	100			$ 200
Lease termination date				Jun. 10, 2020
Restructuring and related expense	2,046	$ 367		$ 6,354	$ 3,361
Restructuring
Restructuring Cost And Reserve [Line Items]
Number of employees terminated | Employee				27
Percentage of employees to be terminated				28.00%
Expected aggregate charges	6,800			$ 6,800
One time severance and employee termination related costs	2,400			2,400
One time retention costs	4,100			4,100
Relocation costs	300			300
Restructuring compensation	2,000			5,200
Paid for restructuring compensation	1,500			2,500
Restructuring reserve balance	$ 2,700			$ 2,700
Restructuring | Scenario, Plan
Restructuring Cost And Reserve [Line Items]
Number of employees terminated | Employee			11

Restructuring Expense - Schedul

Restructuring Expense - Schedule of Restructuring Expenses (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Restructuring And Related Activities [Abstract]
Restructuring compensation	$ 2,046		$ 5,152
Impairment of property and equipment			1,202
Total restructuring and related expense	$ 2,046	$ 367	$ 6,354	$ 3,361

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income Tax Contingency [Line Items]
Income tax benefit	$ 35	$ 5,665	$ 70
State | Earliest Tax Year
Income Tax Contingency [Line Items]
Open tax year		Dec. 31, 2016
State | Latest Tax Year
Income Tax Contingency [Line Items]
Open tax year		Dec. 31, 2018
U.S. Federal Tax Authority | Earliest Tax Year
Income Tax Contingency [Line Items]
Open tax year		Dec. 31, 2016
U.S. Federal Tax Authority | Latest Tax Year
Income Tax Contingency [Line Items]
Open tax year		Dec. 31, 2018
California Tax Authority
Income Tax Contingency [Line Items]
Tax assessment additional period		5 years
CARES Act
Income Tax Contingency [Line Items]
Net operating losses carried back term (in taxable years)		5 years
Net operating losses carried back to offset taxable income percentage		100.00%

Net Loss per Common Share - Sch

Net Loss per Common Share - Schedule of Potentially Dilutive Securities not Included in Calculation of Diluted Per Common Share (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential dilutive securities excluded from diluted net loss per common share would be anti-dilutive	11,960,354	12,329,756	11,960,354	12,329,756
Options to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential dilutive securities excluded from diluted net loss per common share would be anti-dilutive	11,317,276	10,797,308	11,317,276	10,797,308
Restricted Stock Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential dilutive securities excluded from diluted net loss per common share would be anti-dilutive	526,995	1,290,260	526,995	1,290,260
Common stock committed under ESPP
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential dilutive securities excluded from diluted net loss per common share would be anti-dilutive	65,921	180,471	65,921	180,471
Common Stock Warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potential dilutive securities excluded from diluted net loss per common share would be anti-dilutive	50,162	61,717	50,162	61,717