Bolt Biotherapeutics (BOLT) 10-Q 10 Nov 22 2022 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2022	Nov. 03, 2022
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q3
Entity Registrant Name	Bolt Biotherapeutics, Inc.
Entity Central Index Key	0001641281
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		37,660,893
Entity Shell Company	false
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Title of 12(b) Security	Common Stock, $0.00001 par value
Trading Symbol	BOLT
Security Exchange Name	NASDAQ
Entity File Number	001-39988
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	47-2804636
Entity Address, Address Line One	900 Chesapeake
Entity Address, Address Line Two	Drive
Entity Address, City or Town	Redwood City
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94063
City Area Code	650
Local Phone Number	665-9295
Document Quarterly Report	true
Document Transition Report	false

CONDENSED BALANCE SHEETS (Unaud

CONDENSED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 10,617	$ 27,383
Short-term investments	160,513	158,836
Prepaid expenses and other current assets	3,696	2,941
Total current assets	174,826	189,160
Property and equipment, net	6,905	6,158
Operating lease right-of-use assets	22,777	24,445
Restricted cash	1,565	1,565
Long-term investments	38,432	85,348
Other assets	1,000	1,042
Total assets	245,505	307,718
Current liabilities:
Accounts payable	3,828	3,574
Accrued expenses and other current liabilities	14,793	12,384
Deferred revenue	3,169	2,869
Operating lease liabilities	2,384	2,501
Total current liabilities	24,174	21,328
Operating lease liabilities, net of current portion	20,857	21,854
Deferred revenue, non-current	11,828	14,207
Other long-term liabilities	200	210
Total liabilities	57,059	57,599
Commitments and contingencies (Note 7)
Stockholders' equity (deficit):
Preferred stock, $0.00001 par value, authorized share-10,000,000 shares authorized at September 30, 2022 and December 31, 2021; zero shares issued and outstanding at September 30, 2022 and December 31, 2021	0	0
Common stock, $0.00001 par value; 200,000,000 shares authorized at September 30, 2022 and December 31, 2021; 37,660,893 and 37,399,694 shares issued and outstanding at September 30, 2022 and December 31, 2021, respectively	0	0
Additional paid-in capital	465,246	457,430
Accumulated other comprehensive loss	(1,709)	(321)
Accumulated deficit	(275,091)	(206,990)
Total stockholders' equity (deficit):	188,446	250,119
Total liabilities, convertible preferred stock, and stockholders' equity (deficit)	$ 245,505	$ 307,718

CONDENSED BALANCE SHEETS (Una_2

CONDENSED BALANCE SHEETS (Unaudited) (Parenthetical) - $ / shares	Sep. 30, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Preferred Stock, Par or Stated Value Per Share	$ 0.00001	$ 0.00001
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 or Stated Value Per Share	$ 0.00001	$ 0.00001
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares, issued	37,660,893	37,399,694
Common stock, shares, outstanding	37,660,893	37,399,694

CONDENSED STATEMENTS OF OPERATI

CONDENSED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Income Statement [Abstract]
Collaboration revenue	$ 2,112	$ 752	$ 4,318	$ 752
Operating expenses:
Research and development	18,973	19,337	56,278	53,171
General and administrative	5,485	4,941	17,321	13,294
Total operating expense	24,458	24,278	73,599	66,465
Loss from operations	(22,346)	(23,526)	(69,281)	(65,713)
Other income (expense), net
Interest income, net	587	131	1,180	363
Change in fair value of preferred stock right liability				(6,084)
Total other income (expense), net	587	131	1,180	(5,721)
Net loss	(21,759)	(23,395)	(68,101)	(71,434)
Net unrealized gain (loss) on marketable securities	94	(15)	(1,388)	(38)
Comprehensive loss	$ (21,665)	$ (23,410)	$ (69,489)	$ (71,472)
Net loss per share, basic	$ (0.58)	$ (0.63)	$ (1.83)	$ (2.24)
Net loss per share, diluted	$ (0.58)	$ (0.63)	$ (1.83)	$ (2.24)
Weighted-average shares outstanding, basic	37,454,340	37,206,793	37,293,121	31,824,180
Weighted-average shares outstanding, diluted	37,454,340	37,206,793	37,293,121	31,824,180

CONDENSED STATEMENTS OF PREFERR

CONDENSED STATEMENTS OF PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) (Unaudited) - USD ($) $ in Thousands	Total	Convertible Preferred Stock	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit
Beginning Balance at Dec. 31, 2020	$ (104,947)			$ 3,452		$ (108,399)
Beginning Balance, Shares at Dec. 31, 2020			2,130,139
Beginning Balance at Dec. 31, 2020		$ 105,296
Beginning Balance, Shares at Dec. 31, 2020		15,232,275
Issuance of Series C-2 convertible preferred stock, net of issuance cost of $42		$ 51,902
Issuance of Series C-2 convertible preferred stock, net of issuance cost of $42, Shares		5,611,059
Reclassification of convertible preferred stock purchase right liability to equity upon issuance of convertible C-2 preferred stock		$ 31,308
Conversion of convertible preferred stock to common stock	188,506			188,506
Conversion of convertible preferred stock to common stock, Shares			20,843,334
Temporary equity, Conversion of convertible preferred stock to common stock		$ (188,506)
Temporary equity, Conversion of convertible preferred stock to common stock, Shares		(20,843,334)
Issuance of common stock upon initial public offering, net of issuance costs of $22,541	241,959			241,959
Issuance of common stock upon initial public offering, net of issuance costs of $22,541, Shares			13,225,000
Issuance of common stock related to stock purchase agreement	13,638			13,638
Issuance of common stock related to stock purchase agreement, Shares			821,045
Issuance of common stock under employee stock purchase plan	420			420
Issuance of common stock under employee stock purchase plan, Shares			29,685
Issuance of common stock upon exercise of stock options	337			337
Issuance of common stock upon exercise of stock options,Shares			116,266
Issuance of common stock upon exercise of common stock warrants, Shares			82,603
Vesting of early exercised options	114			114
Stock-based compensation	6,358			6,358
Unrealized gain (loss) on available-for-sale investments	(38)				$ (38)
Net loss	(71,434)					(71,434)
Ending Balance at Sep. 30, 2021	274,913			454,784	(38)	(179,833)
Ending Balance, Shares at Sep. 30, 2021			37,248,072
Beginning Balance at Jun. 30, 2021	295,896			452,357	(23)	(156,438)
Beginning Balance, Shares at Jun. 30, 2021			37,191,005
Issuance of common stock upon exercise of stock options	185			185
Issuance of common stock upon exercise of stock options,Shares			57,067
Vesting of early exercised options	16			16
Stock-based compensation	2,226			2,226
Unrealized gain (loss) on available-for-sale investments	(15)				(15)
Net loss	(23,395)					(23,395)
Ending Balance at Sep. 30, 2021	274,913			454,784	(38)	(179,833)
Ending Balance, Shares at Sep. 30, 2021			37,248,072
Beginning Balance at Dec. 31, 2021	250,119			457,430	(321)	(206,990)
Beginning Balance, Shares at Dec. 31, 2021			37,399,694
Beginning Balance at Dec. 31, 2021	0
Vesting of restricted stock units			65,301
Issuance of common stock under employee stock purchase plan	224			224
Issuance of common stock under employee stock purchase plan, Shares			136,711
Issuance of common stock upon exercise of stock options	135			135
Issuance of common stock upon exercise of stock options,Shares			59,187
Vesting of early exercised options	4			4
Stock-based compensation	7,453			7,453
Unrealized gain (loss) on available-for-sale investments	(1,388)				(1,388)
Net loss	(68,101)					(68,101)
Ending Balance at Sep. 30, 2022	188,446			465,246	(1,709)	(275,091)
Ending Balance, Shares at Sep. 30, 2022			37,660,893
Ending Balance at Sep. 30, 2022	0
Beginning Balance at Jun. 30, 2022	207,968			463,103	(1,803)	(253,332)
Beginning Balance, Shares at Jun. 30, 2022			37,641,459
Vesting of restricted stock units			19,434
Stock-based compensation	2,143			2,143
Unrealized gain (loss) on available-for-sale investments	94				94
Net loss	(21,759)					(21,759)
Ending Balance at Sep. 30, 2022	188,446			$ 465,246	$ (1,709)	$ (275,091)
Ending Balance, Shares at Sep. 30, 2022			37,660,893
Ending Balance at Sep. 30, 2022	$ 0

CONDENSED STATEMENTS OF PREFE_2

CONDENSED STATEMENTS OF PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) (Unaudited) (Parenthetical) $ in Thousands	9 Months Ended
	Sep. 30, 2021 USD ($)
Common Stock
Stock issuance cost	$ 22,541
Convertible Preferred Stock
Stock issuance cost	$ 42

CONDENSED STATEMENTS OF CASH FL

CONDENSED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (68,101)	$ (71,434)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,204	832
Stock-based compensation expense	7,453	6,358
Accretion of premium/discount on marketable securities	655	1,833
Change in fair value of convertible preferred stock purchase rights liabilities		6,084
Non-cash lease expense	2,520	1,935
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(713)	(7,187)
Accounts payable and accrued expenses	2,481	7,225
Operating lease liabilities	(1,966)	(831)
Deferred revenue	(2,079)	15,911
Other long-term liabilities	(6)	2
Net cash used in operating activities	(58,552)	(39,272)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of property and equipment	(1,769)	(1,776)
Purchases of marketable securities	(155,345)	(283,688)
Maturities of marketable securities	198,541	32,230
Net cash provided by (used in) investing activities	41,427	(253,234)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of preferred stock, net of issuance cost		51,902
Proceeds from initial public offering, net of issuance cost		244,316
Proceeds from issuance of common stock	359	757
Proceeds from issuance of common stock related to stock purchase agreement		13,638
Net cash provided by financing activities	359	310,613
Net (decrease) increase in cash	(16,766)	18,107
Cash, cash equivalents and restricted cash at beginning of year	28,948	7,107
Cash, cash equivalents and restricted cash at end of period	12,182	25,214
Reconciliation of cash, cash equivalents and restricted cash:
Cash and cash equivalents	10,617	23,649
Restricted cash	1,565	1,565
Total cash, cash equivalents and restricted cash	12,182	25,214
Supplemental schedule of non-cash investing and financing activities:
Vesting of early exercised options	4	114
Purchases of property and equipment included in accounts payable and accrued liabilities	182	591
Deferred offering costs in accounts payable and accrued liabilities	102
Right of use assets obtained in exchange for operating lease obligations	$ 852	$ 14,884

Description of the Business

Description of the Business	9 Months Ended
	Sep. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of the Business	1. Description of the Business Bolt Biotherapeutics, Inc. (the “Company”) is a clinical-stage biopharmaceutical company developing novel immunotherapies for the treatment of cancer. The Company’s pipeline candidates are built on the Company’s deep expertise in myeloid biology and cancer drug development, uniting the targeting precision of antibodies with the power of the innate and adaptive immune system to reprogram the tumor microenvironment for a productive anti-cancer response.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2022
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation The accompanying unaudited condensed financial statements as of September 30, 2022 and for the three and nine months ended September 30, 2022 and 2021 have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) for interim financial information and pursuant to applicable rules and regulations of the SEC regarding interim financial reporting. Accordingly, they do not include all of the information and notes required by U.S. GAAP for complete financial statements. These unaudited condensed financial statements include only normal and recurring adjustments and certain immaterial reclassifications, which are normal in nature, that the Company believes are necessary to a fair statement of the Company’s financial position and the results of its operations and cash flows. The balance sheet as of December 31, 2021 was derived from the audited financial statements as of that date. Certain reclassifications on the condensed statement of cash flows have been made to prior period amounts to conform to current period presentation. These interim financial results are not necessarily indicative of results to be expected for the full year or any other period. These unaudited condensed financial statements and the notes accompanying them should be read in conjunction with the Company’s Annual Report on Form 10-K for the year ended December 31, 2021 . Risks and Uncertainties COVID-19 and Macroeconomics The Company is subject to a number of risks similar to other early-stage biopharmaceutical companies, including, but not limited to, changes in any of the following areas that the Company believes could have a material adverse effect on its future financial position or results of operations: risks related to the successful discovery and development of its product candidates, ability to raise additional capital, development of new technological innovations by its competitors, delay or inability to obtain chemical or biological intermediates from such suppliers required for the synthesis of the Company’s product candidates, including due to the impact of the ongoing COVID-19 pandemic, protection of intellectual property rights, litigation or claims against the Company based on intellectual property rights, and regulatory clearance and market acceptance of the Company’s products. In addition to the ongoing COVID-19 pandemic, global economic and business activities continue to face widespread macroeconomic uncertainties, including labor shortages, inflation and monetary supply shifts, recession risks and potential disruptions from the Russia-Ukraine conflict. The Company continues to actively monitor the impact of these macroeconomic factors on its financial condition, liquidity, operations, and workforce. The extent of the impact of these factors on the Company’s operational and financial performance, including its ability to execute its business strategies and initiatives in the expected time frame, will depend on future developments, which are uncertain and cannot be predicted; however, any continued or renewed disruption resulting from these factors could negatively impact the Company’s business. The Company relies on single source manufacturers and suppliers for the supply of its product candidates. Disruption from these manufacturers or suppliers would have a negative impact on the Company’s business, financial position, and results of operations. Liquidity The Company has incurred net losses and negative cash flows from operations since our inception and anticipates to continue to incur net losses for the foreseeable future. As of September 30, 2022, the Company had cash and cash equivalents and marketable securities of $ 209.6 million and an accumulated deficit of $ 275.1 million. Based upon the Company's current operating plans, the Company believes that its existing cash, cash equivalents and marketable securities will be sufficient to fund its operations for at least the next 12 months following the issuance date of this Quarterly Report on Form 10-Q. In the near term, the Company's primary uses of cash will be to fund the completion of key milestones for BDC-1001 and BDC-3042 and to fund its operations, including research and development activities and employee salaries. This includes significant costs relating to clinical trials and manufacturing the Company's product candidates. The Company's uses of cash in the long term will be similar as the Company advances its research and development activities and pay employee salaries. Most pharmaceutical products require larger clinical trials as development progresses, and the Company expects its funding requirements to grow with the advancement of its programs. The Company's long-term funding requirements will depend on many factors, which are uncertain but include its portfolio prioritization decisions and the success of its collaborations. In turn, the Company's ability to raise additional capital through equity or partnering will depend on the general economic environment in which it operates and its ability to achieve key milestones. 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, liabilities, and the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. On an ongoing basis, the Company evaluates its estimates and assumptions, including those related to revenue recognition, stock-based compensation and accrued liabilities. Management bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ materially from those estimates. Concentrations of Credit Risk Financial instruments that potentially subject the Company to concentration of credit risk consist of cash, cash equivalents and marketable securities. As of September 30, 2022 and December 31, 2021 , most of the Company’s funds were invested with a registered investment manager and custodied at one financial institution, with operating cash kept at a separate financial institution, and account balances may at times exceed federally insured limits. Management believes that the Company is not exposed to significant credit risk due to the financial strength of the depository institutions where the funds are held. Cash and Cash Equivalents The Company considers all highly liquid investments purchased with an original maturity of three months or less to be cash equivalents. As of September 30, 2022 and December 31, 2021 , cash and cash equivalents consisted primarily of bank deposits and money market funds, which were unrestricted as to withdrawal or use. Marketable Securities The Company classifies its marketable securities as available-for-sale and records such assets at estimated fair value in the balance sheets, with unrealized gains and losses that are determined to be temporary, if any, reported as a component of other comprehensive income (loss) within the statements of operations and comprehensive loss and as a separate component of stockholders’ equity (deficit). The Company classifies marketable securities with remaining maturities greater than three months but less than one year as short-term investments, and those with remaining maturities greater than one year are classified as long-term investments. Investments are regularly reviewed for other-than-temporary declines in fair value. The review includes the consideration of the cause of the impairment, including the creditworthiness of the security issuers, the number of investments in an unrealized loss position, the severity and duration of the unrealized losses and whether it is more likely than not that the Company will be required to sell the investments before the recovery of their amortized cost basis. A decline in the fair value of any security below cost that is deemed other than temporary results in a charge to earnings and the establishment of a new cost basis for the security. The Company invests its excess cash balances primarily in corporate debt securities with strong credit ratings. Realized gains and losses are calculated on the specific identification method and recorded as interest income and were immaterial for all periods presented. Restricted Cash As of September 30, 2022 and December 31, 2021 , the Company had $ 1.6 million of long-term restricted cash deposited with a financial institution. The restricted cash is held in separate bank accounts to support letter of credit agreements related to the Company’s facility leases that expire in 2025 and 2031 (see Note 7). Fair Value Measurements Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. Cash and cash equivalents, restricted cash, marketable debt securities, accounts payable, accrued expenses and other current liabilities are reported at their respective fair values in the Company's condensed balance sheets. The carrying amount of the remaining financial instruments approximate fair value due to their short-term nature. Refer to Note 3 for the methodologies and assumptions used in valuing financial instruments. Net Loss Per Share Basic net loss per share is calculated by dividing the net loss by the weighted-average number of shares of common stock outstanding during the period, without consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss by the weighted-average number of common stock and potentially dilutive securities outstanding for the period. For purposes of the diluted net loss per share calculation, convertible preferred stock, stock options, common stock subject to repurchase related to unvested restricted stock awards and early exercise of stock options are considered potentially dilutive securities. Basic and diluted net loss per share is presented in conformity with the two-class method required for participating securities as the convertible preferred stock is considered a participating security because it participates in dividends with common stock. The Company also considers the shares issued upon the early exercise of stock options subject to repurchase to be participating securities because holders of such shares have non-forfeitable dividend rights in the event a dividend is paid on common stock. The holders of all series of convertible preferred stock and the holders of early exercised shares subject to repurchase do not have a contractual obligation to share in the Company’s losses. As such, the net loss was attributed entirely to common stockholders. Because the Company has reported a net loss for all periods presented, diluted net loss per share is the same as basic net loss per share for all periods presented as potentially dilutive securities were anti-dilutive. Recent Accounting Standards From time to time, new accounting standards are issued by the Financial Accounting Standards Board (the “FASB”), or other standard setting bodies and adopted by the Company as of the specified effective date. There have been no new accounting pronouncements issued nor adopted during the three and nine months ended September 30, 2022 that are of significance to the Company’s financial position or results of operations.

Fair Value Measurements and Fai

Fair Value Measurements and Fair Value of Financial Instruments	9 Months Ended
	Sep. 30, 2022
Fair Value Disclosures [Abstract]
Fair Value Measurements and Fair Value of Financial Instruments	3. Fair Value Measurements and Fair Value of Financial Instruments The authoritative guidance on fair value measurements establishes a three-tier fair value hierarchy for disclosure of fair value measurements as follows: Level 1 —Quoted prices in active markets for identical assets or liabilities. Level 2 —Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities, quoted prices in markets that are no t active or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 —U no bservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. Assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires management to make judgments and consider factors specific to the asset or liability. During the three and nine months ended September 30, 2022, financial assets measured on a recurring basis consist of cash invested in money market accounts, short-term investments, and long-term investments. The fair value of short-term and long-term investments is based upon market prices quoted on the last day of the fiscal period or other observable market inputs. The Company obtains pricing information from its investment manager and generally determines the fair value of investment securities using standard observable inputs, including reported trades, broker/dealer quotes, bids and/or offers. There were no transfers within the hierarchy during the three and nine months ended September 30, 2022 or 2021. Marketable securities, all of which are classified as available-for-sale securities, consisted of the following at September 30, 2022 and December 31, 2021 (in thousands): September 30, 2022 Amortized Unrealized Unrealized Estimated Cost Gains Losses Fair Value Asset-backed securities $ 14,950 $ — $ ( 134 ) $ 14,816 U.S. treasury securities 60,751 — ( 830 ) 59,921 Other government agency securities 5,024 — ( 74 ) 4,950 Commercial paper 53,222 — — 53,222 Corporate debt securities 66,707 — ( 671 ) 66,036 Total $ 200,654 $ — $ ( 1,709 ) $ 198,945 December 31, 2021 Amortized Unrealized Unrealized Estimated Cost Gains Losses Fair Value Asset-backed securities $ 34,058 $ — $ ( 18 ) $ 34,040 U.S. treasury securities 39,985 — ( 171 ) 39,814 Other government agency securities 5,068 — ( 22 ) 5,046 Commercial paper 64,956 — — 64,956 Corporate debt securities 100,438 12 ( 122 ) 100,328 Total $ 244,505 $ 12 $ ( 333 ) $ 244,184 At September 30, 2022 and December 31, 2021, the fair values of the Company’s assets, which are measured at fair value on a recurring basis, were determined using the following inputs (in thousands): September 30, 2022 Total (Level 1) (Level 2) (Level 3) Money market funds $ 7,605 $ 7,605 $ — $ — Asset-backed securities 14,816 — 14,816 — U.S. treasury securities 59,921 59,921 — — Other government agency securities 4,950 — 4,950 — Commercial paper 53,222 — 53,222 — Corporate debt securities 66,036 — 66,036 — Total $ 206,550 $ 67,526 $ 139,024 $ — December 31, 2021 Total (Level 1) (Level 2) (Level 3) Money market funds $ 22,917 $ 22,917 $ — $ — Asset-backed securities 34,040 — 34,040 — U.S. treasury securities 39,814 39,814 — — Other government agency securities 5,046 — 5,046 — Commercial paper 64,956 — 64,956 — Corporate debt securities 100,328 — 100,328 — Total $ 267,101 $ 62,731 $ 204,370 $ —

License and Equity Agreement

License and Equity Agreement	9 Months Ended
	Sep. 30, 2022
License And Equity Agreement [Abstract]
License and Equity Agreement	4. License and Equity Agreement License and Equity Agreement with Related Party In May 2015 and June 2018, the Company entered into license agreements (as amended, the “Stanford Agreement”), with The Board of Trustees of the Leland Stanford Junior University (“Stanford”). The Stanford Agreement provides the Company exclusive licenses to certain inventions. As consideration, the Company issued Stanford shares of its common stock and a limited right to purchase equity in future financing. Dr. Edgar G. Engleman, a founder and member of the board of directors of the Company, who is a professor at Stanford, was issued shares of common stock as part of the Company’s Series A financing in September 2016. During the three and nine months ended September 30, 2022, the Company paid Stanford nil and $ 55,000 , respectively, in license and milestone fees under the Stanford Agreements, and paid nil and $ 40,000 in the same periods in 2021, respectively. In addition, the Company paid Stanford $ 28,700 and $ 77,900 during the three and nine months ended September 30, 2022, respectively, for reimbursement of patent maintenance costs which are included as part of general and administrative expense, and paid $ 26,400 and $ 54,700 in the same periods in 2021, respectively. Additionally, the Company is required by the Stanford Agreement to make milestone payments up to an aggregate of $ 0.4 million for the first licensed product that meets certain patent issuance, clinical and regulatory milestones, and an additional milestone payment of $ 0.2 million for each additional regulatory approval. The Company also agreed in the Stanford Agreement to pay Stanford tiered royalties on the Company’s and its sublicensees’ net sales of licensed products, if any, at low single-digit percentage rates, subject to certain reductions. Dr. Engleman is entitled to receive a share of any royalties that the Company pays to Stanford under the Stanford Agreement with respect to the covered intellectual property. No royalty payments have been made to date.

Balance Sheet Components

Balance Sheet Components	9 Months Ended
	Sep. 30, 2022
Balance Sheet Related Disclosures [Abstract]
Balance Sheet Components	5. Balance Sheet Components Property and Equipment, net Property and equipment, net, consist of the following (in thousands): September 30, December 31, Laboratory equipment $ 9,728 $ 7,889 Office equipment 358 369 Leasehold improvements 272 145 Total property and equipment 10,358 8,403 Less accumulated depreciation and amortization ( 3,453 ) ( 2,245 ) Total $ 6,905 $ 6,158 Depreciation expense related to property and equipment was $ 0.4 million and $ 1.2 million for the three and nine months ended September 30, 2022 , respectively, and $ 0.3 million and $ 0.8 million for the same periods in 2021, respectively. Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consist of the following (in thousands): September 30, December 31, Accrued research and development $ 9,333 $ 6,300 Accrued compensation 4,093 4,886 Accrued other 1,367 1,198 Total $ 14,793 $ 12,384

Collaborations

Collaborations	9 Months Ended
	Sep. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Collaborations	6. Collaborations Joint Development and License Agreement with Toray Industries, Inc. In March 2019, the Company entered into a Joint Development and License Agreement (the “Toray Agreement”) with Toray Industries, Inc. (“Toray”) to jointly develop and commercialize a Boltbody™ immune-stimulating antibody conjugate (“ISAC”) containing Toray’s proprietary antibody to treat cancer. The Company determined that the Toray Agreement is a contract with a customer and should be accounted for under ASC 606. In conjunction with the Toray Agreement, the Company entered into a Series T Convertible Preferred Stock Purchase Agreement (the “Series T Agreement”) for the issuance of 717,514 shares of Series T convertible preferred stock to Toray. These contracts have been evaluated together and the consideration in excess of the fair value of the Series T convertible preferred stock of $ 1.5 million has been allocated to the Toray Agreement and included in the total consideration for collaboration revenue. In February 2021, in connection with the Company’s initial public offering ("IPO"), all outstanding shares of Series T convertible preferred stock were converted into shares of the Company’s common stock. In the Toray Agreement, the Company has identified one bundled performance obligation which includes the license rights, research and development services and services associated with participation on a joint steering committee. Collaboration revenue is recognized over time proportionate to the costs that the Company has incurred to perform the services using an input method as a measure of progress towards satisfying the performance obligation, which is based on project hours. Amounts are billed based on estimated variable consideration in the quarter ahead of performance and are trued up on the subsequent quarter’s invoice following the work performed. The cumulative effect of revisions to estimated hours to complete the Company’s performance obligation will be recorded in the period in which changes are identified and amounts can be reasonably estimated. Deferred revenue allocated to the unsatisfied performance obligation is recorded as a contract liability on the balance sheet and will be recognized over time as the services are performed. As of September 30, 2022 and December 31, 2021 , contract liabilities totaling $ 1.5 million at each period-end were recorded in deferred revenue in long-term liabilities on the balance sheet due to the ongoing reevaluation of the research plan and the continued assessment of program development by both parties. The outcome of this reevaluation may impact the scope and timing of such services. The Toray Agreement includes both fixed and variable consideration. Under the Toray Agreement, the Company will be compensated for early-stage development and manufacturing activities based on agreed full-time equivalent rates and actual out of pocket costs incurred through the completion of the first Phase 1 clinical trial for the lead product candidate and Toray is entitled to reimbursement for 50% of such development costs from the Company’s share of revenues collected from the sale or licensing of collaboration products. Although the legal term of the agreement is until collaboration products are no longer sold in the territories covered under the agreement, the parties have present enforceable rights and obligations through the end of the first Phase 1 clinical trial, after which both parties can opt out of continued development under the agreement. As such, the accounting term of the Toray Agreement was considered to terminate upon completion of the first Phase 1 clinical trial. After the conclusion of the first Phase 1 clinical trial, the parties will share equally all costs of development activities necessary for obtaining regulatory approval of collaboration products in the indications in the territories covered under the agreement, unless either party elects to opt out of its co-funding obligations or reduce them by half, which election can be on a region-by-region basis or for the territories covered under the agreement as a whole. Such optional additional items which will be accounted for as contract modifications when development advances past certain milestones and the parties both exercise their opt-in rights. Oncology Research and Development Collaboration with Genmab A/S In May 2021, the Company entered into a License and Collaboration Agreement (the “Genmab Agreement”) with Genmab A/S (“Genmab”). Together, the companies will evaluate Genmab antibodies and bispecific antibody engineering technologies in combination with the Company’s Boltbody ISAC technology platform, with the goal of discovering and developing next-generation bispecific ISACs for the treatment of cancer. Under this research collaboration, the companies will evaluate multiple bispecific ISAC concepts to identify up to three clinical candidates for development. Genmab will fund the research, along with the preclinical and clinical development of these candidates through initial clinical proof of concept. Under the Genmab Agreement, the Company received an upfront payment of $ 10.0 million. The Company determined that the Genmab Agreement is a contract with a customer and should be accounted for under ASC 606. In conjunction with the Genmab Agreement, the Company entered into a stock purchase agreement (the “Genmab SPA”) for the issuance of 821,045 shares of the Company’s common stock to Genmab for a total purchase price of $ 15.0 million. These contracts have been evaluated together and the consideration in excess of the fair value of the common stock of $ 1.4 million has been allocated to the Genmab Agreement and included in the total consideration for collaboration revenue. In the Genmab Agreement, the Company has identified one bundled performance obligation that includes the license rights, research and development services and services associated with participation on a joint research committee. The transaction price includes the $ 10.0 million upfront payment, the $ 1.4 million allocated from the Genmab SPA, and $ 7.0 million of estimated variable consideration related to compensation for research and development services at the agreed upon full-time employee rate and third-party costs. Collaboration revenue is recognized over time proportionate to the costs that the Company has incurred to perform the services using an input method as a measure of progress towards satisfying the performance obligation, which is based on project hours. Compensation for the research and development services are billed in the quarter based on actual hours incurred to satisfy the performance obligation. The cumulative effect of revisions to estimated hours to complete the Company’s performance obligation will be recorded in the period in which changes are identified and amounts can be reasonably estimated. As of September 30, 2022 , receivables of $ 0.6 million related to research and development services performed under the Genmab Agreement were recorded as part of the prepaid expenses and other current assets line item on the balance sheet. Deferred revenue allocated to the unsatisfied performance obligation is recorded as a contract liability on the balance sheet and will be recognized over time as the services are performed. As of September 30, 2022 , contract liabilities totaling $ 8.9 million were recorded in deferred revenue with $ 2.6 million in current liabilities and $ 6.3 million in non-current liabilities on the balance sheet based on the forecasted periods of performance. The following table presents changes in the Company contract liability (in thousands): Balance at December 31, 2021 $ 10,574 Addition—amount billed for research and development services 1,326 Revenue recognized ( 3,032 ) Balance at September 30, 2022 $ 8,868 The Company recorded $ 1.4 million and $ 3.0 million in revenue earned during the three and nine months ended September 30, 2022 , respectively, and $ 0.8 million for each of the same periods in 2021, based on services performed under the Genmab Agreement during the period. Under the Genmab Agreement, the Company will be compensated for research and development services at the agreed upon full-time employee rate and third-party costs through initial clinical proof of concept of the therapeutic candidates, which also represents the period of time both parties have enforceable rights and obligations. As such, the accounting term of the Genmab Agreement was considered to terminate upon completion of the initial clinical proof of concept of the therapeutic candidates, after which both parties can exercise their respective program opt-in rights. The Genmab Agreement includes optional additional items which will be accounted for as contract modifications after initial clinical proof of concept of the therapeutic candidates. With respect to each candidate for which a party has exercised its program opt-in rights and has exclusive global rights, the other party is eligible to receive potential development and sales-based milestone payments and tiered royalties, subject to certain customary reductions, the amount of all such considerations will vary based on the market potential of the applicable territory for which such party has exercised its program opt-in rights. Under the Genmab Agreement, the Company is eligible to receive total potential milestone payments of up to $ 125.0 million in development milestones and $ 160.0 million in sale milestones per therapeutic candidate exclusively developed and commercialized by Genmab, along with tiered royalties at rates from a single digit to mid-teens percentage based on net sales of each therapeutic candidate. However, given the current phase of development of therapeutic candidates under the Genmab Agreement, the Company cannot estimate the probability or timing of achieving these milestones, and, therefore, has excluded all milestone and royalty payments from the transaction prices of the agreement. Oncology Research and Development Collaboration with Innovent Biologics, Inc. In August 2021, the Company entered into a License and Collaboration Agreement (the “Innovent Agreement”) with Innovent Biologics, Inc. (“Innovent”). Together, the companies will leverage Innovent’s proprietary therapeutic antibody portfolio and antibody discovery capability against undisclosed oncology targets in combination with the Company’s Boltbody ISAC technology and myeloid biology expertise to create up to three new candidates for cancer treatments. Innovent will fund the initial research, along with the preclinical and clinical development of these candidates through initial clinical proof of concept. Under the Innovent Agreement, the Company received an upfront payment of $ 5.0 million. The Company determined that the Innovent Agreement is a contract with a customer and should be accounted for under ASC 606. In conjunction with the Innovent Agreement, the Company entered into a stock purchase agreement with Innovent (the “Innovent SPA”) which contains both a put option and call option allowing Innovent and the Company to respectively initiate a market value purchase and sale of the Company’s common stock, for an aggregate investment of up to $ 10.0 million by Innovent, subject to certain share price limitations. The Innovent Agreement and Innovent SPA have been evaluated together and since the options may be exercised at market value by either party, no consideration from the Innovent SPA has been allocated to the Innovent Agreement and included in the total consideration for collaboration revenue. Both options expired unexercised on May 25, 2022 . In the Innovent Agreement, the Company has identified one bundled performance obligation that includes the license rights, research and development services and services associated with participation on a joint research committee. The transaction price includes the $ 5.0 million upfront payment and up to $ 41.5 million of estimated variable consideration related to compensation for research and development services at the agreed upon full-time employee rate and third-party costs. Collaboration revenue is recognized over time proportionate to the costs that the Company has incurred to perform the services using an input method as a measure of progress towards satisfying the performance obligation, which is based on project hours. Amounts are billed based on estimated variable consideration in the quarter ahead of performance and are trued up on the subsequent quarter’s invoice following the work performed. The cumulative effect of revisions to estimated hours to complete the Company’s performance obligation will be recorded in the period in which changes are identified and amounts can be reasonably estimated. Deferred revenue allocated to the unsatisfied performance obligation is recorded as a contract liability on the balance sheet and will be recognized over time as the services are performed. As of September 30, 2022 , contract liabilities totaling $ 4.6 million were recorded in deferred revenue with $ 0.6 million in current liabilities and $ 4.0 million in non-current liabilities on the balance sheet based on the forecasted periods of performance. The following table presents changes in the Company contract liability (in thousands): Balance at December 31, 2021 $ 5,000 Addition—amount billed for research and development services 900 Revenue recognized ( 1,286 ) Balance at September 30, 2022 $ 4,614 The Company recorded $ 0.7 million and $ 1.3 million in revenue earned during the three and nine months ended September 30, 2022 , respectively, based on services performed under the Innovent Agreement during the period. Under the Innovent Agreement, the Company will be compensated for research and development services at the agreed upon full-time employee rate and third-party costs through initial clinical proof of concept of the therapeutic candidates, which also represents the period of time both parties have enforceable rights and obligations. As such, the accounting term of the Innovent Agreement was considered to terminate upon completion of the initial clinical proof of concept of the therapeutic candidates, after which both parties can exercise their respective license rights. The Innovent Agreement includes license options exercisable by each party to exclusively develop, manufacture and commercialize each candidate in a specific territory, which will be accounted for as contract modifications after the initial clinical proof of concept of the therapeutic candidates and the parties have exercised their respective license options with respect to each candidate. With respect to each candidate for which a party has exercised its license option, the other party is eligible to receive a license option exercise fee, potential development and sales-based milestone payments and tiered royalties, subject to certain customary reductions, the amount of all such considerations will vary based on the market potential of the applicable territory for which such party has exercised its license option. Under the Innovent Agreement, the Company is eligible to receive up to $ 28.5 million in potential license option exercise fee, $ 111.5 million in development milestone payments, $ 297.5 million in sales-based milestone payments, and tiered royalties at rates from a mid-single digit to low-teens percentage based on net sales, subject to certain customary reductions, for therapeutic candidates exclusively developed and commercialized by Innovent in specific territories. However, given the current phase of development of therapeutic candidates under the Innovent Agreement, the Company cannot estimate the probability or timing of achieving these milestones, and, therefore, has excluded all license option exercise fee, milestone and royalty payments from the transaction prices of the agreement. Oncology Clinical Trial Collaboration and Supply Agreement with Bristol Myers Squibb In September 2021, the Company entered into a clinical collaboration and supply agreement with Bristol-Myers Squibb Company (“BMS”) to study BDC-1001 in combination with BMS’s PD-1 checkpoint inhibitor nivolumab, for the treatment of HER2-expressing solid tumors (the “BMS Agreement”). Under the BMS Agreement, BMS granted the Company a non-exclusive, non-transferrable, royalty-free license (with a right to sublicense) under its intellectual property to use nivolumab in a clinical trial for a combination therapy of nivolumab and the Company’s proprietary compound, BDC-1001, and has agreed to supply nivolumab at no cost to the Company and the Company will sponsor, fund and conduct the initial Phase 1/2 clinical trial in accordance with an agreed-upon protocol. Both parties will own the study data produced in the clinical trial, other than study data related solely to nivolumab, which will belong solely to BMS, or study data related solely to BDC-1001, which will belong solely to the Company. The parties may conduct additional clinical trials on the combined therapy which may be sponsored and funded by one party, or jointly funded. Given the terms of the BMS Agreement, the Company concluded that it is not within the scope of ASC 808 or ASC 606. Any relevant costs arising from the clinical trial will be expensed as incurred and recorded in research and development expenses. The Company initiated the clinical trial for the combination therapy of nivolumab and BDC-1001 in the fourth quarter of 2021.

Commitment and Contingencies

Commitment and Contingencies	9 Months Ended
	Sep. 30, 2022
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	7. Commitments and Contingencies Leases The Company has operating leases for its corporate office, laboratory and vivarium space in Redwood City, California. On August 7, 2020, the Company executed a non-cancellable lease agreement for 71,646 square feet of space (the “Chesapeake Master Lease”), which consists of 45,690 square feet of additional office, laboratory and vivarium space and includes an extension of 25,956 square feet under an existing lease. The Chesapeake Master Lease has an initial term of ten years from the Commencement Date, with an option to extend the lease for an additional eight-year term. The Chesapeake Master Lease contains rent escalation, and the Company is also responsible for certain operating expenses and taxes throughout the lease term. In addition, the Company is entitled to up to $ 4.8 million of tenant improvement allowance, which is paid directly by the landlord to various vendors. Upon execution of the non-cancellable lease agreement, the Company took control of 10,000 square feet of space, which is subleased as further described below. The remaining 35,690 square feet of additional office, laboratory and vivarium space commenced in June 2021 and the extension of the 25,956 square feet under an existing lease is expected to commence in 2025. In connection with the execution of the Chesapeake Master Lease, the Company entered into two operating lease agreements to sublease portions of the premises to two unrelated third parties. The first sublease agreement, to sublease 10,000 square feet, commenced in August 2020 and expired on August 31, 2022 . The second sublease agreement, to sublease 10,500 square feet, commenced in June 2021 and expires on July 31, 2023 . In August 2022, the second sublease agreement was amended to expand the subleased premises to 11,655 square feet in the first year and further increase to 13,743 square feet in the second year. In addition, the expiration date of the second sublease was also amended to the expiration date of the Chesapeake Master Lease. The subtenant has an early termination option with the early termination date no earlier than September 30, 2024 , and no option to extend the sublease term. Rent for the second sublease is subject to scheduled annual increases and the subtenant is responsible for certain operating expenses and taxes throughout the term under the sublease agreement. Sublease income under the two sublease agreements was approximately $ 0.2 million and $ 0.7 million for the three and nine months ended September 30, 2022 , respectively, and $ 0.2 million and $ 0.5 million for the same periods in 2021. At September 30, 2022 and December 31, 2021, finance right-of-use leases are used to finance capital equipment such as printers or ozone generators and are immaterial. The weighted-average remaining lease term and discount rate related to the Company’s lease liabilities as of September 30, 2022 were 7.6 years and 10.9 %, respectively, for the operating leases. The weighted-average remaining lease term and discount rate related to the Company’s lease liabilities as of December 31, 2021 were 8.0 years and 10.7 %, respectively, for the operating leases. The Company lease discount rates are based on estimates of its incremental borrowing rate, as the discount rates implicit in the Company’s leases cannot be readily determined. As the Company does not have any outstanding debt, the Company estimates the incremental borrowing rate based on its estimated credit rating and available market information. The components of lease expense were as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2022 2021 2022 2021 Total operating lease cost $ 1,051 $ 1,229 $ 3,226 $ 2,721 Supplemental cash flow information related to leases was as follows (in thousands): Nine Months Ended September 30, 2022 2021 Operating cash flows from operating leases $ 3,413 $ 1,884 The following is a schedule by year for future maturities of the Company’s operating lease liabilities and sublease income to be received as of September 30, 2022 (in thousands): Operating Leases Sublease Income 2022 $ 1,247 $ 171 2023 4,726 699 2024 4,886 540 2025 4,340 — 2026 3,484 — Thereafter 16,840 — Total minimum lease payments/sublease income 35,523 1,410 Less imputed interest ( 12,282 ) — Total $ 23,241 $ 1,410 Supply Agreement The Company has entered into a supply agreement with a contract manufacturer pursuant to which the Company may be required to pay milestone payments upon the achievement of specified regulatory milestones. The agreement is cancelable by the Company upon delivering the appropriate prior written notice. At September 30, 2022 , potential future milestone payments under this agreement were up to $ 2.0 million. Guarantees and Indemnifications In the normal course of business, the Company enters into agreements that contain a variety of representations and provide for general indemnification. The Company’s exposure under these agreements is unknown because it involves claims that may be made against the Company in the future. To date, the Company has not paid any claims or been required to defend any action related to its indemnification obligations. As of September 30, 2022, the Company did not have any material indemnification claims that were probable or reasonably possible and consequently had not recorded related liabilities. Legal Proceedings The Company is subject to claims and assessments from time to time in the ordinary course of business but is not aware of any such matters, individually or in the aggregate, that will have a material adverse effect on the Company’s financial position, results of operations or cash flows.

Common Stock

Common Stock	9 Months Ended
	Sep. 30, 2022
Equity [Abstract]
Common Stock	8. Common Stock Shelf Registration and At-The-Market Equity Offering On March 30, 2022, the Company filed a shelf registration statement on Form S-3 (the "Registration Statement"). Pursuant to the Registration Statement, the Company may offer and sell securities having an aggregate public offering price of up to $ 250.0 million. In connection with the filing of the Registration Statement, the Company also entered into a sales agreement with Cowen and Company, LLC ("Cowen"), as sales agent or principal, pursuant to which the Company may issue and sell shares of its common stock for an aggregate offering price of up to $ 75.0 million under an at-the-market (the “ATM”) offering program. Pursuant to the ATM, the Company will pay Cowen a commission rate equal to 3.0 % of the gross proceeds from the sale of any shares of common stock. The Company is not obligated to make any sales of shares of its common stock under the ATM. As of September 30, 2022 , no shares of the Company's common stock have been sold under this ATM.

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2022
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation	9. Stock-Based Compensation 2021 Equity Incentive Plan and 2021 Employee Stock Purchase Plan In January 2021, the Company’s board of directors adopted the 2021 Equity Incentive Plan (the “2021 Plan”) and the Company’s stockholders approved the 2021 Plan. The 2021 Plan authorized issuance of up to 8,075,000 shares of common stock and it became effective upon the execution of the underwriting agreement for the Company’s IPO. In addition, the number of shares of common stock reserved for issuance under the 2021 Plan will automatically increase on the first day of January 1 of each calendar year that commences after the 2021 Plan becomes effective and continuing through and including January 1, 2031, in an amount equal to 5 % of the total number of shares of the Company’s common stock outstanding on December 31, or a lesser number of shares determined by the Company's board of directors or compensation committee. As a result, common stock reserved for issuance under the 2021 Plan was increased by 1,869,984 shares on January 1, 2022. In addition, in January 2021, the Company’s board of directors and stockholders adopted the 2021 Employee Stock Purchase Plan (the “ESPP”). The ESPP authorized issuance of up to 840,000 shares of common stock and it became effective upon the execution of the underwriting agreement for the Company’s IPO. The 2021 ESPP permits participants to purchase common stock through payroll deductions of up to 15 % of their eligible compensation. Employees purchase shares of common stock at a price per share equal to 85 % of the lower of the fair market value at the start or end of the six-month purchase periods within the two-year offering period. In addition, the number of shares of common stock reserved for issuance under the 2021 ESPP will automatically increase on January 1 of each calendar year that commences after the ESPP becomes effective and continuing through and including January 1, 2031, by the lesser of (1) 1 % of the total number of shares of the Company's common stock outstanding on December 31 of the preceding calendar year, (2) 840,000 shares, and (3) a number of shares determined by the Company's board of directors. As a result, common stock reserved for issuance under the 2021 ESPP was increased by 373,996 shares on January 1, 2022. 136,711 total shares were issued under the ESPP during the nine months ended September 30, 2022 and 29,685 shares were issued under the ESPP during the same period in 2021. Performance and Service Based Stock Options In September 2020, the compensation committee of the Company’s board of directors granted 526,018 options to employees that would commence vesting upon the closing of the Series C-2 financing and generally vest monthly over 48 months (the “Performance Awards”). The Company recognizes expense based on the fair value of the Performance Awards over the estimated service period (under the graded vesting method) to the extent the achievement of the related performance criteria is estimated to be probable. The Company determined that the financing milestone was achieved during January 2021. Accordingly, the Company recognized stock-based compensation expense related to the Performance Awards of approximately $ 0.1 million and $ 0.2 million for the three and nine months ended September 30, 2022 , respectively, and $ 0.1 million and $ 0.7 million for the same periods in 2021 , respectively. The weighted-average grant date fair value of the Performance Awards was $ 3.24 per share. Restricted Stock Units In December 2021, the Company issued 336,000 restricted stock units under the 2021 Plan at a grant date fair value of $ 4.51 per share. These restricted stock units vest in equal quarterly installments over three years , subject to the employee's continued employment with, or services to, the Company on each vesting date. Each restricted stock unit represents the right to receive one share of the Company's common stock when and if the applicable vesting conditions are satisfied. Stock-Based Compensation Expense The following table summarizes the components of stock-based compensation expense recognized in the Company’s statement of operations and comprehensive loss (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2022 2021 2022 2021 Research and development $ 834 $ 1,231 $ 3,223 $ 3,328 General and administrative 1,309 995 4,230 3,030 Total $ 2,143 $ 2,226 $ 7,453 $ 6,358

Net Loss Per Share

Net Loss Per Share	9 Months Ended
	Sep. 30, 2022
Earnings Per Share [Abstract]
Net Loss Per Share	10. Net Loss Per Share The following table sets forth the computation of the Company’s basic and diluted net loss per share attributable to common stockholders, which excludes shares which are legally outstanding, but subject to repurchase by the Company (in thousands, except share and per share amounts): Three Months Ended September 30, Nine Months Ended September 30, 2022 2021 2022 2021 Numerator: Net loss $ ( 21,759 ) $ ( 23,395 ) $ ( 68,101 ) $ ( 71,434 ) Denominator: Weighted average common shares outstanding 37,645,895 37,214,513 37,533,016 31,837,227 Weighted average common stock outstanding subject to repurchase related to unvested early exercised stock options and restricted stock awards ( 191,555 ) ( 7,720 ) ( 239,895 ) ( 24,847 ) Weighted average warrants to purchase common stock — — — 11,800 Weighted average common shares outstanding - basic and 37,454,340 37,206,793 37,293,121 31,824,180 Net loss per share attributable to common stockholders, basic $ ( 0.58 ) $ ( 0.63 ) $ ( 1.83 ) $ ( 2.24 ) Potentially dilutive shares to be issued under the ESPP as of September 30, 2022 and 2021 were not included in the calculation of dilutive net loss per share because they would be anti-dilutive and were immaterial. In addition, potential dilutive securities not included in the calculation of diluted net loss per share because to do so would be anti-dilutive are as follows (in common stock equivalent shares): As of September 30, 2022 2021 Common stock options issued and outstanding 7,262,069 5,197,275 Common stock outstanding subject to repurchase related to 156,899 4,966 Total 7,418,968 5,202,241

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2022
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed financial statements as of September 30, 2022 and for the three and nine months ended September 30, 2022 and 2021 have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) for interim financial information and pursuant to applicable rules and regulations of the SEC regarding interim financial reporting. Accordingly, they do not include all of the information and notes required by U.S. GAAP for complete financial statements. These unaudited condensed financial statements include only normal and recurring adjustments and certain immaterial reclassifications, which are normal in nature, that the Company believes are necessary to a fair statement of the Company’s financial position and the results of its operations and cash flows. The balance sheet as of December 31, 2021 was derived from the audited financial statements as of that date. Certain reclassifications on the condensed statement of cash flows have been made to prior period amounts to conform to current period presentation. These interim financial results are not necessarily indicative of results to be expected for the full year or any other period. These unaudited condensed financial statements and the notes accompanying them should be read in conjunction with the Company’s Annual Report on Form 10-K for the year ended December 31, 2021 .
Risks And Uncertainties	Risks and Uncertainties COVID-19 and Macroeconomics The Company is subject to a number of risks similar to other early-stage biopharmaceutical companies, including, but not limited to, changes in any of the following areas that the Company believes could have a material adverse effect on its future financial position or results of operations: risks related to the successful discovery and development of its product candidates, ability to raise additional capital, development of new technological innovations by its competitors, delay or inability to obtain chemical or biological intermediates from such suppliers required for the synthesis of the Company’s product candidates, including due to the impact of the ongoing COVID-19 pandemic, protection of intellectual property rights, litigation or claims against the Company based on intellectual property rights, and regulatory clearance and market acceptance of the Company’s products. In addition to the ongoing COVID-19 pandemic, global economic and business activities continue to face widespread macroeconomic uncertainties, including labor shortages, inflation and monetary supply shifts, recession risks and potential disruptions from the Russia-Ukraine conflict. The Company continues to actively monitor the impact of these macroeconomic factors on its financial condition, liquidity, operations, and workforce. The extent of the impact of these factors on the Company’s operational and financial performance, including its ability to execute its business strategies and initiatives in the expected time frame, will depend on future developments, which are uncertain and cannot be predicted; however, any continued or renewed disruption resulting from these factors could negatively impact the Company’s business. The Company relies on single source manufacturers and suppliers for the supply of its product candidates. Disruption from these manufacturers or suppliers would have a negative impact on the Company’s business, financial position, and results of operations.
Liquidity	Liquidity The Company has incurred net losses and negative cash flows from operations since our inception and anticipates to continue to incur net losses for the foreseeable future. As of September 30, 2022, the Company had cash and cash equivalents and marketable securities of $ 209.6 million and an accumulated deficit of $ 275.1 million. Based upon the Company's current operating plans, the Company believes that its existing cash, cash equivalents and marketable securities will be sufficient to fund its operations for at least the next 12 months following the issuance date of this Quarterly Report on Form 10-Q. In the near term, the Company's primary uses of cash will be to fund the completion of key milestones for BDC-1001 and BDC-3042 and to fund its operations, including research and development activities and employee salaries. This includes significant costs relating to clinical trials and manufacturing the Company's product candidates. The Company's uses of cash in the long term will be similar as the Company advances its research and development activities and pay employee salaries. Most pharmaceutical products require larger clinical trials as development progresses, and the Company expects its funding requirements to grow with the advancement of its programs. The Company's long-term funding requirements will depend on many factors, which are uncertain but include its portfolio prioritization decisions and the success of its collaborations. In turn, the Company's ability to raise additional capital through equity or partnering will depend on the general economic environment in which it operates and its ability to achieve key milestones.
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, liabilities, and the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. On an ongoing basis, the Company evaluates its estimates and assumptions, including those related to revenue recognition, stock-based compensation and accrued liabilities. Management bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ materially from those estimates.
Concentrations of Credit Risk	Concentrations of Credit Risk Financial instruments that potentially subject the Company to concentration of credit risk consist of cash, cash equivalents and marketable securities. As of September 30, 2022 and December 31, 2021 , most of the Company’s funds were invested with a registered investment manager and custodied at one financial institution, with operating cash kept at a separate financial institution, and account balances may at times exceed federally insured limits. Management believes that the Company is not exposed to significant credit risk due to the financial strength of the depository institutions where the funds are held.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments purchased with an original maturity of three months or less to be cash equivalents. As of September 30, 2022 and December 31, 2021 , cash and cash equivalents consisted primarily of bank deposits and money market funds, which were unrestricted as to withdrawal or use.
Marketable Securities	Marketable Securities The Company classifies its marketable securities as available-for-sale and records such assets at estimated fair value in the balance sheets, with unrealized gains and losses that are determined to be temporary, if any, reported as a component of other comprehensive income (loss) within the statements of operations and comprehensive loss and as a separate component of stockholders’ equity (deficit). The Company classifies marketable securities with remaining maturities greater than three months but less than one year as short-term investments, and those with remaining maturities greater than one year are classified as long-term investments. Investments are regularly reviewed for other-than-temporary declines in fair value. The review includes the consideration of the cause of the impairment, including the creditworthiness of the security issuers, the number of investments in an unrealized loss position, the severity and duration of the unrealized losses and whether it is more likely than not that the Company will be required to sell the investments before the recovery of their amortized cost basis. A decline in the fair value of any security below cost that is deemed other than temporary results in a charge to earnings and the establishment of a new cost basis for the security. The Company invests its excess cash balances primarily in corporate debt securities with strong credit ratings. Realized gains and losses are calculated on the specific identification method and recorded as interest income and were immaterial for all periods presented.
Restricted Cash	Restricted Cash As of September 30, 2022 and December 31, 2021 , the Company had $ 1.6 million of long-term restricted cash deposited with a financial institution. The restricted cash is held in separate bank accounts to support letter of credit agreements related to the Company’s facility leases that expire in 2025 and 2031 (see Note 7).
Fair Value Measurements	Fair Value Measurements Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. Cash and cash equivalents, restricted cash, marketable debt securities, accounts payable, accrued expenses and other current liabilities are reported at their respective fair values in the Company's condensed balance sheets. The carrying amount of the remaining financial instruments approximate fair value due to their short-term nature. Refer to Note 3 for the methodologies and assumptions used in valuing financial instruments.
Net Loss Per Share	Net Loss Per Share Basic net loss per share is calculated by dividing the net loss by the weighted-average number of shares of common stock outstanding during the period, without consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss by the weighted-average number of common stock and potentially dilutive securities outstanding for the period. For purposes of the diluted net loss per share calculation, convertible preferred stock, stock options, common stock subject to repurchase related to unvested restricted stock awards and early exercise of stock options are considered potentially dilutive securities. Basic and diluted net loss per share is presented in conformity with the two-class method required for participating securities as the convertible preferred stock is considered a participating security because it participates in dividends with common stock. The Company also considers the shares issued upon the early exercise of stock options subject to repurchase to be participating securities because holders of such shares have non-forfeitable dividend rights in the event a dividend is paid on common stock. The holders of all series of convertible preferred stock and the holders of early exercised shares subject to repurchase do not have a contractual obligation to share in the Company’s losses. As such, the net loss was attributed entirely to common stockholders. Because the Company has reported a net loss for all periods presented, diluted net loss per share is the same as basic net loss per share for all periods presented as potentially dilutive securities were anti-dilutive.
Recent Accounting Standards	Recent Accounting Standards From time to time, new accounting standards are issued by the Financial Accounting Standards Board (the “FASB”), or other standard setting bodies and adopted by the Company as of the specified effective date. There have been no new accounting pronouncements issued nor adopted during the three and nine months ended September 30, 2022 that are of significance to the Company’s financial position or results of operations.

Fair Value Measurements and F_2

Fair Value Measurements and Fair Value of Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2022
Fair Value Disclosures [Abstract]
Schedule of Marketable Securities Classified as Available-for-sale Securities	Marketable securities, all of which are classified as available-for-sale securities, consisted of the following at September 30, 2022 and December 31, 2021 (in thousands): September 30, 2022 Amortized Unrealized Unrealized Estimated Cost Gains Losses Fair Value Asset-backed securities $ 14,950 $ — $ ( 134 ) $ 14,816 U.S. treasury securities 60,751 — ( 830 ) 59,921 Other government agency securities 5,024 — ( 74 ) 4,950 Commercial paper 53,222 — — 53,222 Corporate debt securities 66,707 — ( 671 ) 66,036 Total $ 200,654 $ — $ ( 1,709 ) $ 198,945 December 31, 2021 Amortized Unrealized Unrealized Estimated Cost Gains Losses Fair Value Asset-backed securities $ 34,058 $ — $ ( 18 ) $ 34,040 U.S. treasury securities 39,985 — ( 171 ) 39,814 Other government agency securities 5,068 — ( 22 ) 5,046 Commercial paper 64,956 — — 64,956 Corporate debt securities 100,438 12 ( 122 ) 100,328 Total $ 244,505 $ 12 $ ( 333 ) $ 244,184
Schedule of Fair Values of Assets and Liabilities Measured at Fair Value on Recurring Basis	At September 30, 2022 and December 31, 2021, the fair values of the Company’s assets, which are measured at fair value on a recurring basis, were determined using the following inputs (in thousands): September 30, 2022 Total (Level 1) (Level 2) (Level 3) Money market funds $ 7,605 $ 7,605 $ — $ — Asset-backed securities 14,816 — 14,816 — U.S. treasury securities 59,921 59,921 — — Other government agency securities 4,950 — 4,950 — Commercial paper 53,222 — 53,222 — Corporate debt securities 66,036 — 66,036 — Total $ 206,550 $ 67,526 $ 139,024 $ — December 31, 2021 Total (Level 1) (Level 2) (Level 3) Money market funds $ 22,917 $ 22,917 $ — $ — Asset-backed securities 34,040 — 34,040 — U.S. treasury securities 39,814 39,814 — — Other government agency securities 5,046 — 5,046 — Commercial paper 64,956 — 64,956 — Corporate debt securities 100,328 — 100,328 — Total $ 267,101 $ 62,731 $ 204,370 $ —

Balance Sheet Components (Table

Balance Sheet Components (Tables)	9 Months Ended
	Sep. 30, 2022
Balance Sheet Related Disclosures [Abstract]
Property and Equipment, Net	Property and equipment, net, consist of the following (in thousands): September 30, December 31, Laboratory equipment $ 9,728 $ 7,889 Office equipment 358 369 Leasehold improvements 272 145 Total property and equipment 10,358 8,403 Less accumulated depreciation and amortization ( 3,453 ) ( 2,245 ) Total $ 6,905 $ 6,158
Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consist of the following (in thousands): September 30, December 31, Accrued research and development $ 9,333 $ 6,300 Accrued compensation 4,093 4,886 Accrued other 1,367 1,198 Total $ 14,793 $ 12,384

Collaborations (Tables)

Collaborations (Tables)	9 Months Ended
	Sep. 30, 2022
Genmab Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Schedule of Changes in Contract Liability	The following table presents changes in the Company contract liability (in thousands): Balance at December 31, 2021 $ 10,574 Addition—amount billed for research and development services 1,326 Revenue recognized ( 3,032 ) Balance at September 30, 2022 $ 8,868
Innovent Biologics
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Schedule of Changes in Contract Liability	The following table presents changes in the Company contract liability (in thousands): Balance at December 31, 2021 $ 5,000 Addition—amount billed for research and development services 900 Revenue recognized ( 1,286 ) Balance at September 30, 2022 $ 4,614

Commitment and Contingencies (T

Commitment and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2022
Commitments and Contingencies Disclosure [Abstract]
Components of Lease Expense	The components of lease expense were as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2022 2021 2022 2021 Total operating lease cost $ 1,051 $ 1,229 $ 3,226 $ 2,721
Supplemental Cash Flow Information Related to Leases	Supplemental cash flow information related to leases was as follows (in thousands): Nine Months Ended September 30, 2022 2021 Operating cash flows from operating leases $ 3,413 $ 1,884
Schedule by Year for Future Maturities of Operating Lease Liabilities and Sublease Income to be Received	The following is a schedule by year for future maturities of the Company’s operating lease liabilities and sublease income to be received as of September 30, 2022 (in thousands): Operating Leases Sublease Income 2022 $ 1,247 $ 171 2023 4,726 699 2024 4,886 540 2025 4,340 — 2026 3,484 — Thereafter 16,840 — Total minimum lease payments/sublease income 35,523 1,410 Less imputed interest ( 12,282 ) — Total $ 23,241 $ 1,410

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2022
Share-Based Payment Arrangement [Abstract]
Summary of Components of Stock-Based Compensation Expense Recognized	The following table summarizes the components of stock-based compensation expense recognized in the Company’s statement of operations and comprehensive loss (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2022 2021 2022 2021 Research and development $ 834 $ 1,231 $ 3,223 $ 3,328 General and administrative 1,309 995 4,230 3,030 Total $ 2,143 $ 2,226 $ 7,453 $ 6,358

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	9 Months Ended
	Sep. 30, 2022
Earnings Per Share [Abstract]
Computation of Basic and Diluted Net Loss per Share Attributable to Common Stockholders, which excludes Shares Legally Outstanding	The following table sets forth the computation of the Company’s basic and diluted net loss per share attributable to common stockholders, which excludes shares which are legally outstanding, but subject to repurchase by the Company (in thousands, except share and per share amounts): Three Months Ended September 30, Nine Months Ended September 30, 2022 2021 2022 2021 Numerator: Net loss $ ( 21,759 ) $ ( 23,395 ) $ ( 68,101 ) $ ( 71,434 ) Denominator: Weighted average common shares outstanding 37,645,895 37,214,513 37,533,016 31,837,227 Weighted average common stock outstanding subject to repurchase related to unvested early exercised stock options and restricted stock awards ( 191,555 ) ( 7,720 ) ( 239,895 ) ( 24,847 ) Weighted average warrants to purchase common stock — — — 11,800 Weighted average common shares outstanding - basic and 37,454,340 37,206,793 37,293,121 31,824,180 Net loss per share attributable to common stockholders, basic $ ( 0.58 ) $ ( 0.63 ) $ ( 1.83 ) $ ( 2.24 )
Potentially Dilutive Securities not Included in the Calculation of Diluted Net Loss per Share	potential dilutive securities not included in the calculation of diluted net loss per share because to do so would be anti-dilutive are as follows (in common stock equivalent shares): As of September 30, 2022 2021 Common stock options issued and outstanding 7,262,069 5,197,275 Common stock outstanding subject to repurchase related to 156,899 4,966 Total 7,418,968 5,202,241

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Accounting Policies [Abstract]
Cash and cash equivalents and marketable securities	$ 209,600
Accumulated deficit	(275,091)	$ (206,990)
Restricted cash	$ 1,565	$ 1,565

Fair Value Measurements and F_3

Fair Value Measurements and Fair Value of Financial Instruments - Additional Information (Details) - USD ($)	3 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Fair value, asset, transfers into level 3	$ 0	$ 0
Fair value, asset, transfers out of level 3	0	0
Fair value, liability, transfers into level 3	0	0
Fair value, liability, transfers out of level 3	$ 0	$ 0

Fair Value Measurements and F_4

Fair Value Measurements and Fair Value of Financial Instruments - Schedule of Marketable Securities Classified as Available-for-sale Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	$ 200,654	$ 244,505
Unrealized Gains		12
Unrealized Losses	(1,709)	(333)
Estimated Fair Value	198,945	244,184
Asset Backed Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	14,950	34,058
Unrealized Losses	(134)	(18)
Estimated Fair Value	14,816	34,040
U.S. Treasury Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	60,751	39,985
Unrealized Losses	(830)	(171)
Estimated Fair Value	59,921	39,814
Other Government Agency Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	5,024	5,068
Unrealized Losses	(74)	(22)
Estimated Fair Value	4,950	5,046
Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	53,222	64,956
Estimated Fair Value	53,222	64,956
Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	66,707	100,438
Unrealized Gains		12
Unrealized Losses	(671)	(122)
Estimated Fair Value	$ 66,036	$ 100,328

Fair Value Measurements and F_5

Fair Value Measurements and Fair Value of Financial Instruments - Schedule of Fair Values of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - Recurring Basis - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total asset	$ 206,550	$ 267,101
Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total asset	7,605	22,917
Asset Backed Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total asset	14,816	34,040
U.S. Treasury Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total asset	59,921	39,814
Other Government Agency Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total asset	4,950	5,046
Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total asset	53,222	64,956
Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total asset	66,036	100,328
Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total asset	67,526	62,731
Level 1 | Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total asset	7,605	22,917
Level 1 | U.S. Treasury Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total asset	59,921	39,814
Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total asset	139,024	204,370
Level 2 | Asset Backed Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total asset	14,816	34,040
Level 2 | Other Government Agency Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total asset	4,950	5,046
Level 2 | Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total asset	53,222	64,956
Level 2 | Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total asset	$ 66,036	$ 100,328

License and Equity Agreement -

License and Equity Agreement - Additional Information (Details) - Stanford Agreement - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
License And Equity Agreement [Line Items]
License and milestone fees paid	$ 0	$ 0	$ 55,000	$ 40,000
Additional milestone payment	200,000		200,000
Royalty payments			0
Maximum
License And Equity Agreement [Line Items]
Aggregate millstone payments	400,000		400,000
General and Administrative
License And Equity Agreement [Line Items]
Payments for reimbursement of patent maintenance costs	$ 28,700	$ 26,400	$ 77,900	$ 54,700

Balance Sheet Components - Prop

Balance Sheet Components - Property and Equipment, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 10,358	$ 8,403
Less accumulated depreciation and amortization	(3,453)	(2,245)
Total	6,905	6,158
Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	9,728	7,889
Office Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	358	369
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 272	$ 145

Balance Sheet Components - Addi

Balance Sheet Components - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Balance Sheet Related Disclosures [Abstract]
Depreciation expense	$ 0.4	$ 0.3	$ 1.2	$ 0.8

Balance Sheet Components - Accr

Balance Sheet Components - Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Balance Sheet Related Disclosures [Abstract]
Accrued research and development	$ 9,333	$ 6,300
Accrued compensation	4,093	4,886
Accrued other	1,367	1,198
Total	$ 14,793	$ 12,384

Collaborations - Additional Inf

Collaborations - Additional Information (Details) - USD ($)	1 Months Ended			3 Months Ended		9 Months Ended
	Aug. 31, 2021	May 31, 2021	Mar. 31, 2019	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Consideration in excess of fair value							$ 241,959,000
Collaboration revenue				$ 2,112,000	$ 752,000	$ 4,318,000	$ 752,000
Common Stock
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Common stock sold							13,225,000
Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Potential future milestone payments						2,000,000
Toray Development Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Contract liability				1,500,000		1,500,000		$ 1,500,000
Genmab Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Contract liability				8,868,000		8,868,000		10,574,000
Upfront payment received		$ 10,000,000
Potential future milestone payments		160,000,000
Contract liability, current				2,600,000		2,600,000
Contract liability, non-current				6,300,000		6,300,000
Collaboration revenue				1,400,000	$ 800,000	3,000,000	$ 800,000
Allocated from stock purchase agreement		1,400,000
Variable consideration related to reimbursements for research and development services		$ 7,000,000
Genmab Agreement | Prepaid Expenses and Other Current Assets
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Research and development services receivables						600,000
Genmab Agreement | Common Stock
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Common stock sold		821,045
Consideration in excess of fair value		$ 1,400,000
Purchase price under Stock Purchase Agreement		15,000,000
Genmab Agreement | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Potential future milestone payments		$ 125,000,000
Innovent Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Contract liability				4,614,000		4,614,000		$ 5,000,000
Upfront payment received	$ 5,000,000
Contract liability, current				600,000		600,000
Contract liability, non-current				4,000,000		4,000,000
Collaboration revenue				$ 700,000		1,300,000
Allocated from stock purchase agreement						$ 0
Potential future development milestone payments	111,500,000
Potential future sale milestone payments	297,500,000
Stock purchase agreement expiration term						May 25, 2022
Innovent Agreement | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Variable consideration related to reimbursements for research and development services	41,500,000
Potential license option exercise fee	28,500,000
Innovent Agreement | Maximum | Common Stock
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Aggregate investment under stock purchase agreement	$ 10,000,000
Series T Convertible Preferred Stock | Toray Development Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Common stock sold			717,514
Consideration in excess of fair value			$ 1,500,000

Collaborations - Schedule of Ch

Collaborations - Schedule of Changes in Contract Liability (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2022 USD ($)
Genmab Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Beginning Balance	$ 10,574
Addition - amount billed for research and development services	1,326
Revenue recognized	(3,032)
Ending Balance	8,868
Innovent Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Beginning Balance	5,000
Addition - amount billed for research and development services	900
Revenue recognized	(1,286)
Ending Balance	$ 4,614

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details)		1 Months Ended		3 Months Ended		9 Months Ended
	Aug. 07, 2020 USD ($) ft²	Aug. 31, 2022 ft²	Jun. 30, 2021 ft²	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($) ft²	Sep. 30, 2021 USD ($)	Dec. 31, 2021
Commitments And Contingencies [Line Items]
Sublease income | $						$ 1,410,000
Weighted-average remaining lease term				7 years 7 months 6 days		7 years 7 months 6 days		8 years
Weighted-average discount rate				10.90%		10.90%		10.70%
Maximum
Commitments And Contingencies [Line Items]
Potential future milestone payments | $						$ 2,000,000
Chesapeake Master Lease
Commitments And Contingencies [Line Items]
Operating lease, area of property available	71,646
Operating lease, area of property, additional space available	45,690
Operating lease, area of property, extension space available	25,956		25,956
Operating lease, initial term of contract	10 years
Operating lease, option to extend	true
Operating lease, extended additional term	8 years
Tenant improvement allowance | $	$ 4,800,000
Operating lease, area of property subleased	10,000
Operating lease, area of property, additional space remaining			35,690
Sublease, area of property leased	10,000	11,655
Sublease expiration date	Aug. 31, 2022					Jul. 31, 2023
Increase decrease in operating lease sublease area of property leased		13,743
Sublease, area of property expected to be leased						10,500
Operating sublease, option to extend, description						The subtenant has an early termination option with the early termination date no earlier than September 30, 2024, and no option to extend the sublease term.
Operating sublease, option to extend		false
Sublease income | $				$ 200,000	$ 200,000	$ 700,000	$ 500,000
Chesapeake Master Lease | Maximum
Commitments And Contingencies [Line Items]
Sublease expiration date		Sep. 30, 2024

Commitments and Contingencies_2

Commitments and Contingencies - Components of Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Total operating lease cost	$ 1,051	$ 1,229	$ 3,226	$ 2,721

Commitments and Contingencies_3

Commitments and Contingencies - Supplemental Cash Flow Information Related to Leases (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Operating cash flows from operating leases	$ 3,413	$ 1,884

Commitments and Contingencies_4

Commitments and Contingencies - Schedule by Year for Future Maturities of Operating Lease Liabilities and Sublease Income to be Received (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2022 USD ($)
Operating Leases
Operating Leases, 2022	$ 1,247
Operating Leases, 2023	4,726
Operating Leases, 2024	4,886
Operating Leases, 2025	4,340
Operating Leases, 2026	3,484
Operating Leases, Thereafter	16,840
Operating Leases, Total minimum lease payments	35,523
Less imputed interest	(12,282)
Operating lease liabilities	23,241
Sublease Income
Sublease Income, 2022	171
Sublease Income, 2023	699
Sublease Income, 2024	540
Total Sublease Income	1,410
Sublease Income, Total	$ 1,410

Convertible Preferred Stock - A

Convertible Preferred Stock - Additional Information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2022	Dec. 31, 2021
Class Of Stock [Line Items]
Convertible preferred stock value		$ 0	$ 0
Proceeds from issuance of preferred stock, net of issuance cost	$ 51,902

Common Stock - Additional Infor

Common Stock - Additional Information (Details) - USD ($) $ in Thousands		9 Months Ended
	Mar. 30, 2022	Sep. 30, 2022	Sep. 30, 2021
Class Of Warrant Or Right [Line Items]
Aggregate offering price			$ 241,959
Common Stock
Class Of Warrant Or Right [Line Items]
Common stock sold			13,225,000
Shelf Registration and At-The-Market Equity Offering | Common Stock
Class Of Warrant Or Right [Line Items]
Common stock sold		0
Shelf Registration and At-The-Market Equity Offering | Maximum
Class Of Warrant Or Right [Line Items]
Aggregate offering price	$ 250,000
Shelf Registration and At-The-Market Equity Offering | Cowen and Company, LLC ("Cowen") | Common Stock
Class Of Warrant Or Right [Line Items]
Percentage of gross proceeds from sale of common stock	3%
Shelf Registration and At-The-Market Equity Offering | Cowen and Company, LLC ("Cowen") | Maximum | Common Stock
Class Of Warrant Or Right [Line Items]
Aggregate offering price	$ 75,000

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended			3 Months Ended		9 Months Ended
	Dec. 31, 2021	Dec. 31, 2021	Jan. 31, 2021	Sep. 30, 2020	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Jan. 01, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense							$ 7,453	$ 6,358
Performance and Service Based Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares issued				526,018
Vesting period				48 months
Stock-based compensation expense					$ 100	$ 100	$ 200	$ 700
Weighted-average grant date fair value of awards				$ 3.24
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares issued		336,000
Vesting period		3 years
Weighted-average grant date fair value of awards		$ 4.51
Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of common stock under employee stock purchase plan, Shares							136,711	29,685
2021 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance									1,869,984
2021 Plan | Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares authorized for issuance			8,075,000
Percentage equal to number of shares of common stock outstanding	5%
2021 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage equal to number of shares of common stock outstanding	1%
Common stock reserved for issuance					840,000		840,000		373,996
Purchase price of stock as percentage of fair market value			85%
2021 Employee Stock Purchase Plan | Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares authorized for issuance			840,000
Plan offering period			2 years
Issuance of common stock under employee stock purchase plan, Shares							136,711	29,685
2021 Employee Stock Purchase Plan | Common Stock | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of eligible compensation for payroll deductions to purchase stock			15%

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Components of Stock-Based Compensation Expense Recognized (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 2,143	$ 2,226	$ 7,453	$ 6,358
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	834	1,231	3,223	3,328
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 1,309	$ 995	$ 4,230	$ 3,030

Net Loss Per Share - Computatio

Net Loss Per Share - Computation of Basic and Diluted Net Loss per Share Attributable to Common Stockholders, which excludes Shares Legally Outstanding (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Numerator:
Net loss	$ (21,759)	$ (23,395)	$ (68,101)	$ (71,434)
Denominator:
Weighted average common shares outstanding	37,645,895	37,214,513	37,533,016	31,837,227
Weighted average common stock outstanding subject to repurchase related to unvested early exercised stock options and restricted stock awards	(191,555)	(7,720)	(239,895)	(24,847)
Weighted average warrants to purchase common stock				11,800
Weighted average common shares outstanding - basic	37,454,340	37,206,793	37,293,121	31,824,180
Weighted average common shares outstanding - diluted	37,454,340	37,206,793	37,293,121	31,824,180
Net loss per share attributable to common stockholders, basic	$ (0.58)	$ (0.63)	$ (1.83)	$ (2.24)
Net loss per share attributable to common stockholders, diluted	$ (0.58)	$ (0.63)	$ (1.83)	$ (2.24)

Net Loss Per Share - Potentiall

Net Loss Per Share - Potentially Dilutive Securities not Included in the Calculation of Diluted Net Loss per Share (Details) - shares	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities not included in the calculation of diluted net loss per share	7,418,968	5,202,241
Common Stock Options Issued and Outstanding
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities not included in the calculation of diluted net loss per share	7,262,069	5,197,275
Common Stock Outstanding Subject to Repurchase Related to Unvested Early Exercised Stock Options and Restricted Stock Awards
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities not included in the calculation of diluted net loss per share	156,899	4,966