10-Q

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-Q

(Mark One)

☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the quarterly period ended June 30, 2021

OR

☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from                to                

Commission File Number 001-39988

Bolt Biotherapeutics, Inc.

(Exact name of Registrant as specified in its Charter)

Delaware	47-2804636
(State or other jurisdiction of incorporation or organization)	(I.R.S. Employer Identification No.)
900 Chesapeake Drive Redwood City, CA	94063
(Address of principal executive offices)	(Zip Code)

Registrant’s telephone number, including area code: (650) 665-9295

Securities registered pursuant to Section 12(b) of the Act:

Title of each class	Trading Symbol(s)	Name of each exchange on which registered
Common Stock, $0.00001 par value	BOLT	The Nasdaq Global Select Market

Indicate by check mark whether the Registrant: (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the Registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    Yes  ☒    No  ☐

Indicate by check mark whether the Registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the Registrant was required to submit such files).    Yes  ☒    No  ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

Large accelerated filer	☐	Accelerated filer	☐
Non-accelerated filer	☒	Smaller reporting company	☒
Emerging growth company	☒

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.  ☒

Indicate by check mark whether the Registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).    Yes  ☐    No  ☒

As of August 6, 2021, the registrant had 37,201,444 shares of common stock outstanding.

Table of Contents

		Page
PART I FINANCIAL INFORMATION
Item 1.	Financial Statements (unaudited)	1
	Condensed Balance Sheets as of June 30, 2021 and December 31, 2020	1
	Condensed Statements of Operations and Comprehensive Loss for the Three and Six Months Ended June 30, 2021 and 2020	2
	Condensed Statements of Convertible Preferred Stock and Stockholders’ Deficit for the Three and Six Months Ended June 30, 2021 and 2020	3
	Condensed Statements of Cash Flows for the Six Months Ended June 30, 2021 and 2020	5
	Notes to the Condensed Financial Statements	6
Item 2.	Management’s Discussion and Analysis of Financial Condition and Results of Operations	17
Item 3.	Quantitative and Qualitative Disclosures About Market Risk	24
Item 4.	Controls and Procedures	24
PART II OTHER INFORMATION
Item 1.	Legal Proceedings	25
Item 1A.	Risk Factors	25
Item 2.	Unregistered Sales of Equity Securities and Use of Proceeds	25
Item 3.	Defaults Upon Senior Securities	25
Item 4.	Mine Safety Disclosures	25
Item 5.	Other Information	25
Item 6.	Exhibits	26
	Signatures	27

i

SPECIAL Note Regarding Forward-Looking Statements

This Quarterly Report on Form 10-Q contains forward-looking statements within the meaning of Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”). All statements other than statements of historical facts contained in this Quarterly Report are forward-looking statements, including statements regarding:

• any impact of the COVID-19 pandemic, or responses to the pandemic, on our business, collaborations, clinical trials or personnel;

• our expectations regarding the potential benefits of our strategy and technology;

• our expectations regarding the operation of our product candidates, collaborations and related benefits;

• our beliefs regarding our industry;

• our beliefs regarding the success, cost and timing of our product candidate development and collaboration activities and current and future clinical trials and studies;

• our beliefs regarding the potential markets for our product candidates, collaborations and our and our collaborators’ ability to serve those markets;

• our ability to attract and retain key personnel;

• our ability to obtain funding for our operations, including funding necessary to complete further development and any commercialization of our product candidates; and

• regulatory developments in the United States (the “U.S.”) and foreign countries, with respect to our product candidates.

These statements involve known and unknown risks, uncertainties and other important factors that may cause our actual results, performance and achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements.

In some cases, you can identify forward-looking statements by terminology such as “may,” “will,” “should,” “could,” “expects,” “intends,” “plans,” “anticipates,” “believes,” “estimates,” “predicts,” “potential,” “continue,” or the negative of these terms or other comparable terminology. These forward-looking statements are only predictions. We have based these forward-looking statements largely on our current expectations and projections about future events and financial trends that we believe may affect our business, financial condition and results of operations. These forward-looking statements speak only as of the date of this Quarterly Report on Form 10-Q and are subject to a number of risks, uncertainties and assumptions, including those described in Part I, Item 1A, "Risk Factors" in our Annual Report on Form 10-K for the year ended December 31, 2020 filed with the SEC on March 31, 2021. The events and circumstances reflected in our forward-looking statements may not be achieved or occur and actual results could differ materially from those projected in the forward-looking statements. Moreover, we operate in an evolving environment. New risk factors and uncertainties may emerge from time to time, and it is not possible for management to predict all risk factors and uncertainties. Except as required by applicable law, we do not plan to publicly update or revise any forward-looking statements contained herein, whether as a result of any new information, future events, changed circumstances or otherwise.

We have common law trademark rights in the unregistered marks “Bolt Biotherapeutics, Inc.,” “Boltbody,” and the Bolt logo in certain jurisdictions. Solely for convenience, trademarks and tradenames referred to in this Quarterly Report appear without the ^® and ^™ symbols, but those references are not intended to indicate, in any way, that we will not assert, to the fullest extent under applicable law, our rights or that the applicable owner will not assert its rights, to these trademarks and tradenames.

ii

PART I – FINANCIAL INFORMATION

Item 1. Financial Statements

BOLT BIOTHERAPEUTICS, INC.

CONDENSED BALANCE SHEETS

(Unaudited, in thousands, except share and per share amounts)

	June 30,			December 31,
	2021			2020
Assets
Current assets:
Cash and cash equivalents	$	58,302		$	5,542
Short-term investments		186,686			17,296
Prepaid expenses and other current assets		3,163			2,523
Total current assets		248,151			25,361
Property and equipment, net		4,551			4,083
Operating lease right-of-use assets		25,977			12,267
Finance lease right-of-use assets		25			34
Restricted cash		1,565			1,565
Deferred offering costs		—			2,357
Long-term investments		65,938			—
Other assets		867			875
Total assets	$	347,074		$	46,542
Liabilities, convertible preferred stock, and stockholders' equity (deficit)
Current liabilities:
Accounts payable	$	1,614		$	1,598
Accrued expenses and other current liabilities		10,983			6,663
Deferred revenue		4,330			1,502
Operating lease liabilities		2,323			1,501
Total current liabilities		19,250			11,264
Operating lease liabilities, net of current portion		23,160			9,376
Deferred revenue, non-current		8,535			—
Convertible preferred stock purchase right liability, non-current		—			25,224
Other long-term liabilities		233			329
Total liabilities		51,178			46,193
Commitments and contingencies (Note 7)
Convertible preferred stock, $0.00001 par value; 10,000,000 shares and 20,843,367 shares authorized at June 30, 2021 and December 31, 2020, respectively; zero and 15,232,275 shares issued and outstanding at June 30, 2021 and December 31, 2020, respectively.		—			105,296
Stockholders' equity (deficit):
Common stock, $0.00001 par value; 200,000,000 shares and 198,000,000 shares authorized at June 30, 2021 and December 31, 2020, respectively; 37,191,005 and 2,130,139 shares issued and outstanding at June 30, 2021 and December 31, 2020, respectively.		—			—
Additional paid-in capital		452,357			3,452
Accumulated other comprehensive loss		(23	)		—
Accumulated deficit		(156,438	)		(108,399	)
Total stockholders' equity (deficit):		295,896			(104,947	)
Total liabilities, convertible preferred stock, and stockholders' equity (deficit)	$	347,074		$	46,542

The accompanying notes are an integral part of these unaudited condensed financial statements.

1

BOLT BIOTHERAPEUTICS, INC.

CONDENSED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS

(Unaudited, in thousands, except share and per share amounts)

	Three Months Ended June 30,						Six Months Ended June 30,
	2021			2020			2021			2020
Collaboration revenue	$	—		$	67		$	—		$	231
Operating expenses:
Research and development		19,707			9,166			33,834			15,953
General and administrative		4,054			2,011			8,353			4,133
Total operating expense		23,761			11,177			42,187			20,086
Loss from operations		(23,761	)		(11,110	)		(42,187	)		(19,855	)
Other income (expense), net
Interest income, net		176			51			232			163
Change in fair value of preferred stock right liability		—			—			(6,084	)		—
Total other income (expense), net		176			51			(5,852	)		163
Net loss		(23,585	)		(11,059	)		(48,039	)		(19,692	)
Net unrealized gain (loss) on marketable securities		41			11			(23	)		1
Comprehensive loss	$	(23,544	)	$	(11,048	)	$	(48,062	)	$	(19,691	)
Net loss per share, basic and diluted	$	(0.64	)	$	(5.29	)	$	(1.65	)	$	(9.45	)
Weighted-average shares outstanding, basic and diluted		36,595,112			2,089,320			29,088,267			2,083,197

The accompanying notes are an integral part of these unaudited condensed financial statements.

2

BOLT BIOTHERAPEUTICS, INC.

CONDENSED STATEMENTS OF CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS’ EQUITY (DEFICIT)

(Unaudited, in thousands, except share amounts)

	Three Months Ended June 30, 2021
											Accumulated
	Convertible								Additional		Other						Total
	Preferred Stock				Common				Paid-In		Comprehensive			Accumulated			Stockholders'
	Shares		Amount		Shares		Amount		Capital		Loss			Deficit			Equity (Deficit)
Balance at March 31, 2021		—	$	—		36,331,846	$	—	$	436,165	$	(64	)	$	(132,853	)	$	303,248
Issuance of common stock related to stock purchase agreement		—		—		821,045		—		13,638		—			—			13,638
Issuance of common stock under employee stock purchase plan		—		—		29,685		—		420		—			—			420
Issuance of common stock upon exercise of stock options		—		—		8,429		—		23		—			—			23
Vesting of early exercised options and restricted stock awards		—		—		—		—		88		—			—			88
Stock-based compensation		—		—		—		—		2,023		—			—			2,023
Unrealized gain on available-for-sale investments		—		—		—		—		—		41			—			41
Net loss		—		—		—		—		—		—			(23,585	)		(23,585	)
Balance at June 30, 2021		—	$	—		37,191,005	$	—	$	452,357	$	(23	)	$	(156,438	)	$	295,896
	Three Months Ended June 30, 2020
											Accumulated
	Convertible								Additional		Other						Total
	Preferred Stock				Common				Paid-In		Comprehensive			Accumulated			Stockholders'
	Shares		Amount		Shares		Amount		Capital		Loss			Deficit			Equity (Deficit)
Balance at March 31, 2020		10,070,102	$	77,505		1,937,803	$	—	$	2,089	$	(10	)	$	(56,304	)	$	(54,225	)
Issuance of Series C-1 convertible preferred stock, net of issuance costs of $225 and convertible preferred stock purchase right liability of $13,479		5,162,173		27,851		—		—		—		—			—			—
Issuance of common stock upon exercise of stock options		—		—		1,540		—		5		—			—			5
Vesting of early exercised options and restricted stock awards		—		—		—		—		4		—			—			4
Stock-based compensation		—		—		—		—		223		—			—			223
Unrealized gain on available-for-sale investments		—		—		—		—		—		11			—			11
Net loss		—		—		—		—		—		—			(11,059	)		(11,059	)
Balance at June 30, 2020		15,232,275	$	105,356		1,939,343	$	—	$	2,321	$	1		$	(67,363	)	$	(65,041	)

3

BOLT BIOTHERAPEUTICS, INC.

CONDENSED STATEMENTS OF CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS’ EQUITY (DEFICIT)

(Unaudited, in thousands, except share amounts)

	Six Months Ended June 30, 2021
													Accumulated
	Convertible										Additional		Other						Total
	Preferred Stock						Common				Paid-In		Comprehensive			Accumulated			Stockholders'
	Shares			Amount			Shares		Amount		Capital		Loss			Deficit			Equity (Deficit)
Balance at December 31, 2020		15,232,275		$	105,296			2,130,139	$	—	$	3,452	$	—		$	(108,399	)	$	(104,947	)
Issuance of Series C-2 convertible preferred stock, net of issuance cost of $42		5,611,059			51,902			—		—		—		—			—			—
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		(20,843,334	)	$	(188,506	)		20,843,334		—		188,506		—			—			188,506
Issuance of common stock upon initial public offering, net of issuance costs of $22,541		—			—			13,225,000		—		241,959		—			—			241,959
Issuance of common stock upon exercise of common stock warrants		—			—			82,603		—		—		—			—			—
Issuance of common stock related to stock purchase agreement		—			—			821,045		—		13,638		—			—			13,638
Issuance of common stock under employee stock purchase plan		—			—			29,685		—		420								420
Issuance of common stock upon exercise of stock options		—			—			59,199		—		152		—			—			152
Vesting of early exercised options and restricted stock awards		—			—			—		—		98		—			—			98
Stock-based compensation		—			—			—		—		4,132		—			—			4,132
Unrealized loss on available-for-sale investments		—			—			—		—		—		(23	)		—			(23	)
Net loss		—			—			—		—		—		—			(48,039	)		(48,039	)
Balance at June 30, 2021		—		$	—			37,191,005	$	—	$	452,357	$	(23	)	$	(156,438	)	$	295,896
	Six Months Ended June 30, 2020
													Accumulated
	Convertible										Additional		Other						Total
	Preferred Stock						Common				Paid-In		Comprehensive			Accumulated			Stockholders'
	Shares			Amount			Shares		Amount		Capital		Loss			Deficit			Equity (Deficit)
Balance at December 31, 2019		10,070,102		$	77,505			1,921,642	$	—	$	1,825	$	—		$	(47,671	)	$	(45,846	)
Issuance of Series C-1 convertible preferred stock, net of issuance costs of $225 and convertible preferred stock purchase right liability of $13,479		5,162,173			27,851			—		—		—		—			—			—
Issuance of common stock upon exercise of stock options		—			—			17,701		—		39		—			—			39
Vesting of early exercised options and restricted stock awards		—			—			—		—		9		—			—			9
Stock-based compensation		—			—			—		—		448		—			—			448
Unrealized gain on available-for-sale investments		—			—			—		—		—		1			—			1
Net loss		—			—			—		—		—		—			(19,692	)		(19,692	)
Balance at June 30, 2020		15,232,275		$	105,356			1,939,343	$	—	$	2,321	$	1		$	(67,363	)	$	(65,041	)

The accompanying notes are an integral part of these unaudited condensed financial statements.

4

BOLT BIOTHERAPEUTICS, INC.

CONDENSED STATEMENTS OF CASH FLOWS

(Unaudited, in thousands)

	Six Months Ended June 30,
	2021			2020
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$	(48,039	)	$	(19,692	)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization		528			211
Stock-based compensation expense		4,132			448
Accretion of premium/discount on marketable securities		1,034			(53	)
Unrealized gain (loss) on marketable securities, net		(23	)		1
Change in fair value of convertible preferred stock purchase rights liabilities		6,084			—
Non-cash lease expense		1,174			885
Changes in operating assets and liabilities:
Prepaid expenses and other assets		(632	)		(382	)
Accounts payable and accrued expenses		4,110			(438	)
Operating lease liabilities		(278	)		(2,821	)
Deferred revenue		11,363			(69	)
Other long-term liabilities		2			7
Net cash used in operating activities		(20,545	)		(21,903	)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of property and equipment		(761	)		(1,213	)
Purchases of marketable securities		(247,768	)		(13,235	)
Maturities of marketable securities		11,406			5,247
Net cash used in investing activities		(237,123	)		(9,201	)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of preferred stock, net of issuance cost		51,902			41,546
Proceeds from initial public offering, net of issuance cost		244,316			—
Proceeds from issuance of common stock related to stock purchase agreement		13,638			—
Proceeds from issuance of common stock		572			39
Net cash provided by financing activities		310,428			41,585
Net increase in cash		52,760			10,481
Cash, cash equivalents and restricted cash at beginning of year		7,107			35,410
Cash, cash equivalents and restricted cash at end of period	$	59,867		$	45,891
Reconciliation of cash, cash equivalents and restricted cash:
Cash and cash equivalents	$	58,302		$	45,307
Restricted cash		1,565			584
Total cash, cash equivalents and restricted cash	$	59,867		$	45,891
Supplemental schedule of non-cash investing and financing activities:
Vesting of early exercised options	$	98		$	9
Purchases of property and equipment included in accounts payable and accrued liabilities	$	226		$	280
Deferred offering costs in accounts payable and accrued liabilities	$	—		$	216
Right of use assets obtained in exchange for operating lease obligations	$	14,884		$	324

The accompanying notes are an integral part of these unaudited condensed financial statements.

5

BOLT BIOTHERAPEUTICS, INC.

NOTES TO CONDENSED FINANCIAL STATEMENTS

(Unaudited)

1. Description of the Business

Bolt Biotherapeutics, Inc. (the “Company”) is a clinical-stage biotechnology company pioneering a new class of immuno-oncology agents that combine the targeting precision of antibodies with the power of both the innate and adaptive immune systems.

Initial Public Offering and Related Transactions

On February 9, 2021, the Company completed its initial public offering (“IPO”) pursuant to a registration statement on Form S-1 (File No. 333-252136) that was declared effective by the Securities and Exchange Commission (the “SEC”) on February 4, 2021, and sold an aggregate of 13,225,000 shares of its common stock, including the full exercise of the underwriters’ option to purchase 1,725,000 shares, at a price per share of $20.00. Proceeds from the IPO, net of underwriting discounts, commissions and offering costs, were approximately $242.0 million.

In addition, each of the following occurred on February 4, 2021, in connection with the completion of the Company’s IPO:

• the conversion of all outstanding shares of convertible preferred stock into 20,843,334 shares of the Company’s common stock; and

• the amendment and restatement of the Company’s certificate of incorporation, authorizing 200,000,000 shares of common stock and 10,000,000 shares of undesignated preferred stock.  

2. Summary of Significant Accounting Policies

Basis of Presentation

The accompanying unaudited condensed financial statements as of June 30, 2021 and for the three and six months ended June 30, 2021 and 2020 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 fairly state the Company’s financial position and the results of its operations and cash flows. The balance sheet as of December 31, 2020 was derived from the audited financial statements as of that date. 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, 2020.

Reverse Stock Split

On January 26, 2021, the Company amended and restated its amended and restated certificate of incorporation to effect a 1-for-7 reverse stock split of the Company’s outstanding common stock and convertible preferred stock. The par value and authorized shares of the common stock were not adjusted as a result of the reverse stock split. All issued and outstanding common stock, options to purchase common stock, early exercised options and per share amounts contained in the financial statements have been retroactively adjusted to give effect to the reverse stock split for all periods presented.

Other Risks and Uncertainties

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 and 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 current COVID-19 pandemic, protection of intellectual property rights, litigation or claims against the Company based on intellectual property rights, regulatory clearance and market acceptance of the Company’s products. 

6

The current COVID-19 pandemic, which is impacting worldwide economic activity, poses the risk that the Company or its employees, contractors, suppliers and other partners may be prevented from conducting business activities for an indefinite period of time, including due to shutdowns that may be requested or mandated by governmental authorities. The extent to which the COVID-19 pandemic will impact the Company’s business will depend on future developments that are highly uncertain and cannot be predicted at this time. The preparation of financial statements in conformity with generally accepted accounting principles requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. The extent to which the COVID-19 pandemic may directly or indirectly impact the Company’s financial statements is highly uncertain and subject to change. Management considered the potential impact of the COVID-19 pandemic on its estimates and assumptions and there was not a material impact to the Company’s condensed financial statements as of and for the three and six months ended June 30, 2021; however, actual results could differ from those estimates and there may be changes to management’s estimates in future periods.

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.

Use of Estimates

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. On an ongoing basis, the Company evaluates its estimates and assumptions, including those related to revenue recognition, the valuation of common stock, stock-based compensation, convertible preferred stock purchase right liabilities 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.

Deferred Offering Costs

The Company capitalized certain legal, accounting and other third-party fees that were directly related to the Company’s IPO. After the completion of the IPO in February 2021, the total deferred offering costs of $4.0 million were offset against the proceeds from the IPO and reclassified to additional paid-in capital in the accompanying the balance sheets. At December 31, 2020, deferred offering costs totaling $2.4 million were included as non-current assets in the accompanying balance sheet.

Concentrations of Credit Risk

Financial instruments that potentially subject the Company to concentration of credit risk consist of cash, cash equivalents and marketable securities. At June 30, 2021 and December 31, 2020, most of the Company’s funds are invested with a registered investment manager and custodied at one financial institution, with working capital 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 June 30, 2021 and December 31, 2020, 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. 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

7

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 June 30, 2021 and December 31, 2020, 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 our 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 to be 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 six months ended June 30, 2021 that are of significance to the Company’s financial position or results of operations.

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 not active or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.

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.

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During the three and six months ended June 30, 2021, 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. Financial liabilities measured at fair value on a recurring basis include the convertible preferred stock purchase rights liabilities described below.

There were no transfers within the hierarchy during the three and six months ended June 30, 2021 and 2020.

Marketable securities, all of which are classified as available-for-sale securities, consisted of the following at June 30, 2021 and December 31, 2020 (in thousands):

	June 30, 2021
	Amortized		Unrealized		Unrealized			Estimated
	Cost		Gains		Losses			Fair Value
Asset-backed securities	$	38,644	$	3	$	(6	)	$	38,641
U.S. treasury securities		29,993		—		(12	)		29,981
Other government agency securities		5,098		—		(5	)		5,093
Commercial paper		90,819		—		—			90,819
Corporate debt securities		88,092		16		(18	)		88,090
Total	$	252,646	$	19	$	(41	)	$	252,624

	December 31, 2020
	Amortized		Unrealized		Unrealized			Estimated
	Cost		Gains		Losses			Fair Value
Asset-backed securities	$	2,639	$	—	$	—		$	2,639
U.S. treasury securities		1,300		—		—			1,300
Commercial paper		6,795		—		—			6,795
Corporate debt securities		6,562		1		(1	)		6,562
Total	$	17,296	$	1	$	(1	)	$	17,296

At June 30, 2021 and December 31, 2020, the fair values of the Company’s assets and liabilities, which are measured at fair value on a recurring basis, were determined using the following inputs (in thousands):

	June 30, 2021
	Total		(Level 1)		(Level 2)		(Level 3)
Money market funds	$	54,700	$	54,700	$	—	$	—
Asset-backed securities		38,641		—		38,641		—
U.S. treasury securities		29,981		—		29,981		—
Other government agency securities		5,093		—		5,093		—
Commercial paper		90,819		—		90,819		—
Corporate debt securities		88,090		—		88,090		—
Total	$	307,324	$	54,700	$	252,624	$	—

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	December 31, 2020
	Total		(Level 1)		(Level 2)		(Level 3)
Money market funds	$	3,921	$	3,921	$	—	$	—
Asset-backed securities		2,640		—		2,640		—
U.S. treasury securities		1,300		1,300		—		—
Commercial paper		6,795		—		6,795		—
Corporate debt securities		6,561		—		6,561		—
Total	$	21,217	$	5,221	$	15,996	$	—
Liabilities:
Preferred stock purchase rights liability	$	25,224	$	—	$	—	$	25,224

Level 3 liabilities that are measured at fair value on a recurring basis consist of the convertible preferred stock purchase right liabilities. The following table provides a summary of changes in the estimated fair value of the financial instruments using significant Level 3 inputs (in thousands):

	Series C Convertible Preferred Stock Purchase Right Liability
Balance at December 31, 2020	$	25,224
Change in fair value		6,084
Reclassification to equity		(31,308	)
Balance at June 30, 2021	$	—

The fair value of the convertible preferred stock purchase right liabilities is estimated using an income-based approach incorporating probability considerations for different scenarios. The main assumptions include the probability and timing of the tranche closing, and the estimated value of the Company’s equity at that time. In January 2021, the Company issued the additional shares of Series C-2 convertible preferred stock and accordingly, this contractual obligation was settled, and the preferred stock purchase right liability was remeasured to its fair value and reclassified to permanent equity. The fair value of the convertible preferred stock purchase right liability immediately prior to settlement was increased to $31.3 million as a result of the estimated probability of the occurrence of the second closing of Series C convertible preferred stock increasing to 80%, timing related to the occurrence of the second closing decreasing to 0.06 years and the increase in the future expected value of the Series C preferred shares to $16.25 per share.

4. License and Equity Agreement

License and Equity Agreement with Related Party

In May 2015 and June 2018, the Company entered into license agreements (the “Stanford Agreement”), as amended, 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. 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.

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5. Balance Sheet Components

Property and Equipment, net

Property and equipment, net, consist of the following (in thousands):

	June 30, 2021			December 31, 2020
Laboratory equipment	$	6,028		$	5,253
Leasehold Improvements		67			—
Office equipment		214			69
Total property and equipment		6,309			5,322
Less accumulated depreciation and amortization		(1,758	)		(1,239	)
Total	$	4,551		$	4,083

Depreciation expense related to property and equipment was $0.2 million and $0.5 million for the three and six months ended June 30, 2021, respectively, and $0.1 million and $0.2 million for the same periods in 2020, respectively.

Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consist of the following (in thousands):

	June 30, 2021		December 31, 2020
Accrued research and development	$	7,054	$	3,199
Accrued compensation		2,414		2,885
Accrued other		1,515		579
Total	$	10,983	$	6,663

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 Development 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 Development Agreement is a contract with a customer and should be accounted for under ASC 606. In conjunction with the Toray Development 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 Development agreement and included in the total consideration for collaboration revenue. In February 2021, in connection with the Company’s IPO, all outstanding shares of Series T convertible preferred stock were converted into shares of the Company’s common stock.

In the Toray Development 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, which is expected to take place through the first half of 2022. As of June 30, 2021 and December 31, 2020, contract liabilities totaling $1.5 million at each period-end were recorded in deferred revenue in current liabilities on the balance sheet. The Toray Development Agreement includes 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 Bolt’s ISAC technology platform, with the goal of discovering and developing next-generation bispecific ISACs for

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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, Bolt received an upfront payment of $10.0 million and is eligible to receive total potential milestone payments of up to $285.0 million per therapeutic candidate exclusively developed and commercialized by Genmab, along with tiered royalties at rates from a mid-single digit to mid-teens percentage, subject to certain customary reductions. 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 “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 $6.1 million of estimated variable consideration related to reimbursements 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 June 30, 2021, contract liabilities totaling $11.4 million was recorded in deferred revenue in current and non-current liabilities on the balance sheet. There was no revenue earned during the three and six months ended June 30, 2021, as no services had been performed under the Genmab Agreement during these periods. 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 and the parties exercise their respective program opt in rights.

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 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. As of June 30, 2021, the operating lease right-of-use assets and operating lease liabilities for the 45,690 square feet of additional space were $18.5 million and $19.2 million, respectively.

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 will expire on July 31, 2022. The second sublease agreement, to sublease 10,500 square feet, commenced in June 2021 and will expire on July 31, 2023. Rent for both subleases are subject to scheduled annual increases and the subtenants are responsible for certain operating expenses and taxes throughout the term under the sublease agreements. The subtenants have no option to extend the sublease term. Sublease income under the two sublease agreements for the three and six months ended June 30, 2021, was approximately $0.2 million and $0.3 million, respectively.

At June 30, 2021 and December 31, 2020, finance right-of-use leases are used to finance capital equipment such as printers or ozone generators and it is immaterial.

The weighted-average remaining lease term and discount rate related to the Company’s lease liabilities as of June 30, 2021 were 8.4 years and 10.8%, 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, 2020 were 6.3 years and 9.5%, 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

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rate based on its estimated credit rating and available market information.

The components of lease expense were as follows (in thousands):

	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Total operating lease cost	$	902	$	603	$	1,669	$	1,196

Supplemental cash flow information related to leases was as follows (in thousands):

	Six Months Ended June 30,
	2021		2020
Operating cash flows from operating leases	$	666	$	3,133

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 June 30, 2021 (in thousands):

	Operating Leases			Sublease Income
2021	$	2,446		$	646
2022		4,994			1,048
2023		4,612			403
2024		4,772			—
2025		4,227			—
Thereafter		19,709			—
Total minimum lease payments/sublease income		40,760			2,097
Less imputed interest		(15,277	)		—
Total	$	25,483		$	2,097

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 June 30, 2021, 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 June 30, 2021, 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.

8. Convertible Preferred Stock

Issuance of Series C-1 and Series C-2 Convertible Preferred Stock

In June 2020, the Company entered into a preferred stock purchase agreement (the “Series C Agreement”) with existing and new investors to raise up to $93.5 million in two separate tranches. The first tranche closed in June 2020 and the Company raised $41.3 million, net of issuance costs of $0.2 million, and issued 5,162,173 shares of Series C-1 convertible preferred stock at $8.05 per share. In addition, the investors agreed to buy and the Company agreed to sell up to 5,611,065 shares of Series C-2 convertible

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preferred stock at a price per share of $9.2575, for potential additional gross proceeds of $51.9 million, upon the achievement of certain milestones as defined in the agreement.

The commitment made by the investors to invest in the second tranche of the Series C Agreement was considered a separate freestanding financial instrument and was recorded as a Convertible Preferred Stock Purchase Right Liability in the amount of $13.5 million upon the issuance of the first tranche of the Series C-1 convertible preferred stock in June 2020. The commitment was accounted for at fair value during the period it was outstanding with changes in fair value recorded as other income (expense) in the statement of operations and comprehensive loss. During the three months ended March 31, 2021, changes in fair value of this liability totaling $6.1 million have been recorded in other income (expense) in the statement of operations and comprehensive loss. In January 2021, the Company issued the additional 5,611,059 shares of Series C-2 convertible preferred stock for net proceeds of $51.9 million and accordingly, this contractual obligation was settled and the preferred stock purchase right liability was remeasured to its fair value and reclassified to permanent equity. In February 2021, all outstanding shares of convertible preferred stock were converted into the Company’s common stock in connection with the IPO.

9. COMMON STOCK

Common Stock Warrants

In July 2018, the Company issued 249,218 warrants to purchase common stock to the Series B investors in the first tranche. The warrants were deemed to be freestanding instruments indexed to the Company’s common stock and met the requirements for equity classification. The warrants had an expiration date of July 26, 2028 and were exercisable at the option of the warrant holder for $0.07 per share. In February 2021, all outstanding warrants were exercised to purchase 82,603 shares of the Company’s common stock in connection with the IPO.

10. STOCK-BASED COMPENSATION

Approval of 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, 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. During the three and six months ended June 30, 2021, 29,685 shares had been issued under the 2021 ESPP.

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 $0.6 million for the three and six months ended June 30, 2021, respectively. The weighted-average grant date fair value of the Performance Awards was $3.24 per share. 

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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 June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Research and development	$	1,077	$	98	$	2,097	$	198
General and administrative		946		125		2,035		250
Total	$	2,023	$	223	$	4,132	$	448

Early Exercise Liability

Some of the options granted under the 2015 Plan may be exercised prior to the time that the options have vested, provided that such shares remain subject to repurchase until such time as they have vested. The right to repurchase these shares lapses over the vesting periods, which are generally four years. As of June 30, 2021 and December 31, 2020, there were 10,904 and 47,180, respectively, unvested shares representing an early exercise liability of approximately $28,000 and $0.1 million, respectively. The unvested shares purchased by the employees are not deemed, for accounting purposes, to be outstanding.

11. 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 June 30,						Six Months Ended June 30,
	2021			2020			2021			2020
Numerator:
Net loss	$	(23,585	)	$	(11,059	)	$	(48,039	)	$	(19,692	)
Denominator:
Weighted average common shares outstanding		36,617,390			1,937,510			29,104,021			1,935,575
Weighted average common stock outstanding subject to repurchase related to unvested early exercised stock options and restricted stock awards		(22,279	)		(20,213	)		(33,553	)		(24,401	)
Weighted average warrants to purchase common stock		—			172,023			17,798			172,023
Weighted average common shares outstanding - basic and    diluted		36,595,112			2,089,320			29,088,267			2,083,197
Net loss per share attributable to common stockholders, basic    and diluted	$	(0.64	)	$	(5.29	)	$	(1.65	)	$	(9.45	)

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Potentially 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):

	Three and Six Months Ended
	2021		2020
Convertible preferred stock		—		15,232,275
Common stock options issued and outstanding		5,091,714		1,992,801
Common stock outstanding subject to repurchase related to    unvested early exercised stock options and restricted    stock awards		10,904		16,132
Total		5,102,618		17,241,208

The ESPP did not exist in 2020, and the potentially dilutive shares to be issued under the ESPP as of June 30, 2021 were not included in the calculation of dilutive net loss per share because they would be anti-dilutive and were immaterial.

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Item 2. Management’s Discussion and Analysis of Financial Condition and Results of Operations.

The following discussion and analysis of our financial condition as of June 30, 2021 and results of operations for the three and six months ended June 30, 2021 and 2020 should be read in conjunction with our condensed financial statements and related notes thereto included elsewhere in this Quarterly Report on Form 10-Q and in our other SEC filings, including our Annual Report on Form 10-K for the year ended December 31, 2020, filed with the SEC on March 31, 2021. Except as otherwise indicated herein or as the context otherwise requires, references in this Quarterly Report on Form 10-Q to “Bolt” “the Company,” “we,” “us” and “our” refer to Bolt Biotherapeutics, Inc.

Overview

We are a clinical-stage biotechnology company pioneering a new class of immuno-oncology agents that combine the targeting precision of antibodies with the power of both the innate and adaptive immune systems. Our proprietary Boltbody™ ISAC approach uses immunostimulants to engage and activate myeloid cells, including macrophages and dendritic cells, that directly kill tumor cells via phagocytosis and expose tumor neoantigens to the adaptive immune system. This leads to recruitment of cytotoxic T cells and additional tumor-killing myeloid cells thereby converting immunologically “cold” tumors to “hot” tumors. We believe that this process leads to the development of systemic immunological memory with epitope spreading to neoantigens that is critical to achieving a long-term anti-tumor response. Our lead product candidate BDC-1001 is a HER2 Boltbody ISAC comprised of a HER2-targeting biosimilar of trastuzumab conjugated to one of our proprietary TLR7/8 agonists for the treatment of patients with HER2-expressing solid tumors, including those with HER2-low tumors. We have demonstrated robust single-agent, anti-tumor activity in multiple preclinical models, including elimination of large tumors (~500 mm3), as well as tumors that are refractory to trastuzumab or ado-trastuzumab emtansine. In our preclinical safety studies, BDC-1001 was well tolerated and no adverse safety signals were observed. We believe these findings are encouraging for the therapeutic potential of BDC-1001. We initiated a Phase 1/2 trial of BDC-1001 in the first quarter of 2020 for the treatment of patients with HER2-expressing solid tumors. We are currently in the dose-escalation portion of the trial and expect to move into Phase 2 dose-expansion cohorts in 2021 in key solid tumor indications with unmet medical need. We believe that our preliminary Phase 1/2 data provide us with clinical proof of concept for our HER2 Boltbody ISAC approach. We are also advancing additional Boltbody ISAC product candidates targeting carcinoembryonic antigen (“CEA”) and PD-L1, both of which are currently in preclinical development. We anticipate advancing our CEA Boltbody ISAC BDC-2034 into the clinic in 2022. We expect to designate our next clinical candidate in the second half of 2021.

Since our inception in January 2015, we have focused primarily on organizing and staffing our company, business planning, licensing, developing intellectual property, raising capital, developing our product candidates and conducting preclinical studies and early clinical trials. We have not recorded any revenue from product sales. To date, our only revenue has been derived from our collaboration with Toray. In March 2019, we entered into the Toray Development Agreement, to jointly develop and commercialize a Boltbody ISAC utilizing Toray’s proprietary antibody. Prior to the completion of our initial public offering in February 2021, we funded our operations primarily through private placements of our convertible preferred stock for gross proceeds of $173.7 million, including Toray’s purchase of 717,514 shares of Series T convertible preferred stock for gross proceeds of $10.0 million and the January 2021 issuance and sale of 5,611,059 shares of Series C-2 preferred stock for net proceeds of $51.9 million. In February 2021, we completed our initial public offering of 13,225,000 shares of our common stock at a price to the public of $20.00 per share, including the exercise in full by the underwriters of their option to purchase 1,725,000 additional shares of our common stock. Including the option exercise, the aggregate net proceeds to us from the offering was approximately $242.0 million, net of underwriting discounts, commissions and other offering expenses. In May 2021, we entered into an oncology research and development collaboration with Genmab to evaluate Genmab antibodies and bispecific antibody engineering technologies in combination with Bolt’s proprietary Boltbody ISAC technology platform, with the goal of discovering and developing next-generation bispecific ISACs for the treatment of cancer. The research collaboration will evaluate multiple bispecific ISAC product candidate concepts with the potential 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, we received an upfront payment of $10.0 million, and under a separate SPA, Genmab invested $15.0 million in our common stock.

We have incurred operating losses since our inception. Our net losses were $48.0 million, $60.7 million and $30.5 million for the six months ended June 30, 2021 and the years ended December 31, 2020 and 2019, respectively. As of June 30, 2021, we had an accumulated deficit of $156.4 million. Substantially all of our net losses have resulted from costs incurred in connection with our research and development programs and from general and administrative costs associated with our operations. We expect to continue to incur significant expenses and increasing operating losses for the foreseeable future, and we further expect our expenses will increase substantially as we:

• conduct our ongoing and planned clinical trials;

• continue our research and development programs;

• expand our clinical, regulatory, quality and manufacturing capabilities;

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• seek regulatory approvals for our product candidates; and

• operate as a public company.

Our net losses may fluctuate significantly from quarter-to-quarter and year-to-year, depending on the timing of our planned clinical trials and preclinical studies, and our expenditures on other research and development activities.

Components of Results of Operations

Revenue

To date our only revenue has been collaboration revenue derived from our collaboration with Toray. We are collaborating with Toray to develop a Boltbody ISAC that incorporates a proprietary Toray antibody against a novel tumor antigen target. We are jointly responsible for early-stage development and for providing technical and regulatory support, and Toray will pay for the program expenses through the end of Phase 1 development. In conjunction with the collaboration, Toray purchased 717,514 shares of our Series T convertible preferred stock for $10.0 million. We evaluated the collaboration together with Toray’s purchase of Series T convertible preferred stock and allocated $1.5 million from the stock purchase proceeds to deferred revenue, which we recognize, together with payments received from Toray for reimbursement based on agreed-upon full-time equivalent rates and out of pocket costs, as collaboration revenue over time as we fulfill our performance obligation to Toray.

In May 2021, we entered into an oncology research and development collaboration with Genmab to evaluate Genmab antibodies and bispecific antibody engineering technologies in combination with Bolt’s proprietary Boltbody ISAC technology platform, with the goal of discovering and developing next-generation bispecific ISACs for the treatment of cancer. The research collaboration 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. In conjunction with the collaboration, Genmab purchased 821,045 shares of our common stock for $15.0 million. We evaluated the collaboration together with Genmab’s purchase of our common stock and allocated $1.4 million from the stock purchase proceeds to deferred revenue, which we will recognize, together with payments received from Genmab for reimbursement based on agreed-upon full-time equivalent rates and out of pocket costs, as collaboration revenue over time as we fulfill our performance obligation to Genmab.

We expect that any collaboration revenue we generate from our current collaborations, and from any future collaboration partners, will fluctuate in the future as a result of the timing and results of development activities and the timing and amount paid, including upfront and milestone payments, and other factors.

We have not generated any revenue from product sales, and we do not expect to generate any revenue from product sales unless and until we obtain regulatory approval of and commercialize one of our product candidates.

Operating Expenses

Research and Development

Research and development expenses have related primarily to early research and discovery activities and to preclinical and clinical development of our product candidates. Research and development expenses are recognized as incurred and payments made prior to the receipt of goods or services to be used in research and development are capitalized until the goods or services are received.

Research and development expenses include:

• costs related to manufacturing our product candidates for clinical trials and preclinical studies, including fees paid to third-party manufacturers;

• salaries, payroll taxes, employee benefits and stock-based compensation charges for those individuals involved in research and development efforts;

• external research and development expenses, including lab materials and supplies and payments to contract research organizations (“CROs”), investigative sites and consultants to conduct our clinical trials and preclinical and non-clinical studies; and 

• facilities and other allocated expenses which include direct and allocated expenses for rent, insurance and other supplies.

Our direct research and development expenses consist principally of external costs, such as fees paid to CROs and consultants in connection with our preclinical and toxicology studies and costs related to manufacturing materials for our preclinical studies. Since our inception and through June 30, 2021, the vast majority of our third-party expenses related to the research and development of BDC-1001. With the exception of our collaboration with Toray, we do not allocate employee costs and costs associated with our

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discovery efforts, laboratory supplies and facilities, including other indirect costs, to specific product candidates because these costs are associated with multiple programs and, as such, are not separately classified. We use internal resources primarily to conduct our research as well as for managing our preclinical development, process development, manufacturing and clinical development activities. We deploy our personnel across all of our research and development activities and, as our employees work across multiple programs, we do not currently track our costs by product candidate.

We plan to substantially increase our research and development expenses for the foreseeable future as we continue the development of our product candidates, particularly as product candidates in later stages of development generally have higher development costs than those in earlier stages of development. We cannot determine with certainty the timing of initiation, the duration or the completion costs of future clinical trials and preclinical studies of our product candidates due to the inherently unpredictable nature of clinical and preclinical development. Clinical and preclinical development timelines, the probability of success and development costs can differ materially from expectations.

We anticipate that we will make determinations as to which product candidates and development programs to pursue and how much funding to direct to each product candidate or program on an ongoing basis in response to the results of ongoing and future preclinical studies and clinical trials, regulatory developments and our ongoing assessments as to each product candidate’s commercial potential. We will need to raise substantial additional capital in the future. In addition, we cannot forecast which product candidates may be subject to future collaborations, when such arrangements will be secured, if at all, and to what degree such arrangements would affect our development plans and capital requirements.

Our future clinical development costs may vary significantly based on factors such as:

• the number and scope of preclinical and IND-enabling studies;

• per-patient trial costs;

• the number of trials required for approval;

• the number of sites included in the trials;

• the countries in which the trials are conducted;

• the length of time required to enroll eligible patients;

• the number of patients who participate in the trials;

• the number of doses that patients receive;

• the drop-out or discontinuation rates of patients;

• potential additional safety monitoring requested by regulatory agencies;

• the duration of patient participation in the trials and through all follow-up;

• the cost and timing of manufacturing our product candidates;

• the phase of development of our product candidates; and

• the safety and efficacy profile of our product candidates.

General and Administrative

General and administrative expenses consist primarily of salaries and employee-related costs, including stock-based compensation, for personnel in executive, finance and other administrative functions. Other significant costs include legal fees relating to intellectual property and corporate matters, professional fees for accounting and consulting services and facility-related costs.

We expect our general and administrative expenses will increase for the foreseeable future to support our increased research and development activities and increased costs of operating as a public company. These increased costs will likely include higher expenses related to audit, legal, regulatory and tax-related services associated with maintaining compliance with Nasdaq and SEC requirements, director and officer insurance premiums and investor relations costs associated with operating as a public company.

Change in Fair Value of Preferred Stock Purchase Right Liability

In connection with the issuance of our Series C-1 convertible preferred stock in June 2020, the investors agreed to buy, and we agreed to sell, additional shares of such preferred convertible stock at the original issue price upon the achievement of pre-defined milestones. These contractual obligations were required to be accounted for as liabilities and remeasured to fair value at each reporting

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date, with any change in the fair value reported as a component of other income (expense). In January 2021, with the completion of the Series C-2 convertible preferred stock, this contractual obligation was settled, and the preferred stock purchase right liability was remeasured to fair value on the purchase date and reclassified to permanent equity.

Results of Operations

Comparison of the Three and Six Months Ended June 30, 2021 and 2020

	Three Months Ended June 30,									Six Months Ended June 30,
	2021			2020			Change			2021			2020			Change
	(Unaudited, in thousands)									(Unaudited, in thousands)
Collaboration revenue	$	—		$	67		$	(67	)	$	—		$	231		$	(231	)
Operating expenses:
Research and development		19,707			9,166			10,541			33,834			15,953			17,881
General and administrative		4,054			2,011			2,043			8,353			4,133			4,220
Total operating expenses		23,761			11,177			12,584			42,187			20,086			22,101
Loss from operations		(23,761	)		(11,110	)		(12,651	)		(42,187	)		(19,855	)		(22,332	)
Other income (expense), net:
Interest income, net		176			51			125			232			163			69
Change in fair value of preferred stock purchase right    liability		—			—			—			(6,084	)		—			(6,084	)
Other income (expense), net		176			51			125			(5,852	)		163			(6,015	)
Net loss and comprehensive loss	$	(23,585	)	$	(11,059	)	$	(12,526	)	$	(48,039	)	$	(19,692	)	$	(28,347	)

Collaboration Revenue

Revenue was nil for the three and six months ended June 30, 2021, and $67,000 and $0.2 million for the three and six months ended June 30, 2020, respectively. Revenue in 2020 was generated from the execution of the Toray Development Agreement in March 2019 and the recognition of revenue over time as we fulfill our performance obligations to Toray. We did not perform any services towards satisfying the performance obligation as defined in the Toray Development Agreement or Genmab Agreement during the first half of 2021. We expect to perform services to further our collaborations with Toray and Genmab in the remainder of 2021.

Research and Development Expenses

Research and development expenses were $19.7 million and $33.8 million for the three and six months ended June 30, 2021, respectively, and $9.2 million and $16.0 million for three and six months ended June 30, 2020, respectively. The increase of $10.5 million between the comparable three months periods was primarily due to a $5.8 million increase in manufacturing expenses related to BDC-1001 and BDC-2034, a $2.3 million increase in personnel-related expenses due to an increase in headcount, a $1.3 million increase in facility-related expenses, and a $1.1 million increase in clinical trial expenses. The increase of $17.9 million between the comparable six-month periods was primarily due to a $9.6 million increase in manufacturing expenses related to BDC-1001 and BDC-2034, a $4.9 million increase in personnel-related expenses due to increase in headcount, a $2.2 million increase in facility-related expenses, and a $0.7 million increase in clinical trial expenses.

General and Administrative Expenses

General and administrative expenses were $4.1 million and $8.4 million for the three and six months ended June 30, 2021, respectively, and $2.0 million and $4.1 million for three and six months ended June 30, 2020, respectively. The increase of $2.1 million between the comparable three months periods was primarily due to a $1.7 million increase in personnel-related expenses due to increase in and headcount and increase in professional services expenses related to consulting services, legal fees and other professional services. The increase of $4.2 million between the comparable six-month periods was primarily due to a $3.0 million increase in personnel-related expenses due to an increase in headcount and increase in professional services expenses related to accounting services, legal fees and other professional services.

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Other Income, Net

Interest Income, Net

Interest income was $0.2 million for each of the three and six months ended June 30, 2021, and $51,000 and $0.2 million for the three and six months ended June 30, 2020, respectively. The interest income, net was primarily comprised of interest income from marketable securities.

Change in Fair Value of Convertible Preferred Stock Purchase Right Liability

The change in fair value of convertible preferred stock purchase right liability was nil and $6.0 million for the three and six months ended June 30, 2021, and nil for each of the three and six months ended June 30, 2020. The balance in 2021 derived from the outstanding Series C-2 preferred stock purchase right liability from the Series C Agreement completed in June 2020. Upon the exercise of the preferred stock purchase right with the completion of the Series C-2 Closing in January 2021, we remeasured the Series C-2 preferred stock purchase right liability to fair value and reclassified to permanent equity on the balance sheets.

Liquidity and Capital Resources

Sources of Liquidity

We have incurred net losses and negative cash flows from operations since our inception and anticipate we will continue to incur net losses for the foreseeable future. As of June 30, 2021, we had cash and cash equivalents, and marketable securities of $310.9 million and an accumulated deficit of $156.4 million. Our net losses were $48.0 million, $60.7 million, and $30.5 million for the six months ended June 30, 2021 and years ended December 31, 2020 and 2019, respectively, and we expect to incur additional losses in the future.

The following table sets forth a summary of our cash flows for each of the periods indicated:

	Six Months Ended June 30,
	2021			2020
	(Unaudited, in thousands)
Net cash provided by (used in)
Operating activities	$	(20,545	)	$	(21,903	)
Investing activities		(237,123	)		(9,201	)
Financing activities		310,428			41,585
Net increase (decrease) in cash, cash equivalents and restricted    cash	$	52,760		$	10,481

Operating Activities

Net cash used in operating activities was $20.5 million and $21.9 million for the six months ended June 30, 2021 and 2020, respectively. Net cash used in operating activities for the six months ended June 30, 2021 was primarily due to our net loss of $48.0 million, adjusted for $12.9 million of non-cash charges and a $14.6 million change in operating assets and liabilities. The non-cash charges were primarily comprised of $6.1 million related to the change in fair value of Series C convertible preferred stock purchase right liabilities, $4.1 million for stock-based compensation, $1.2 million of non-cash lease-related expense, $0.5 million for depreciation and amortization expense, and $1.0 million for accretion of discount on marketable securities. The change in net operating assets was primarily due to a $11.4 million increase in deferred revenue related to Genmab Agreement and an increase in accounts payable and accrued expenses, offset by an increase in our prepaid expense and other current assets and a decrease in operating lease liabilities. Net cash used in operating activities for the same period in 2020 was primarily due to our net loss of $19.7 million, adjusted for $1.5 million of non-cash charges and a $3.7 million change in operating assets and liabilities. The non-cash charges were primarily comprised of $0.9 million of non-cash lease related expense, $0.4 million for stock-based compensation, and $0.2 million for depreciation and amortization expense. The change in net operating assets was primarily due to decreases in our operating lease liabilities and accounts payable and accrued expenses, as well as an increase in prepaid expenses and other assets.

Investing Activities

Net cash used in investing activities was $237.1 million and $9.2 million for six months ended June 30, 2021 and 2020, respectively. The net cash used in investing activities for the six months ended June 30, 2021 was primarily due to $247.8 million purchases of marketable securities and $0.8 million in purchases of property and equipment, offset by $11.4 million in maturity of marketable securities. The net cash used in investment activities for the same period in 2020 was due to $13.2 million in purchases of

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marketable securities and $1.2 million in purchases of property and equipment, offset by $5.2 million in maturities of marketable securities.

Financing Activities

Net cash provided by financing activities was $310.4 million and $41.6 million for the six months ended June 30, 2021 and 2020, respectively. The net cash provided by financing activities for the six months ended June 30, 2021 was primarily due to net proceeds of $244.3 million in connection with our IPO that was completed in February 2021, $51.9 million of net proceeds from the issuance of 5,611,059 shares of Series C-2 preferred stock in January 2021, $13.6 million of net proceeds from issuance of common stock related to Genmab SPA, and $0.6 million of net proceeds from the issuance of common stock from the 2021 ESPP and exercise of stock options. Net cash provided by financing activities for the same period in 2020 was primarily due to a $41.5 million net proceeds from the issuance of 5,162,173 shares of Series C-1 preferred stock in June 2020 and net proceeds from the issuance of common stock from the exercise of stock options.

Funding Requirements

Based upon our current operating plans, we believe that our existing cash, cash equivalents and marketable securities will be sufficient to fund our operations for at least the next 12 months. However, our forecast of the period of time through which our financial resources will be adequate to support our operations is a forward-looking statement that involves risks and uncertainties, and actual results could vary materially. We have based this estimate on assumptions that may prove to be wrong, and we could deplete our capital resources sooner than we expect. Additionally, the process of testing product candidates in clinical trials is costly, and the timing of progress and expenses in these trials is uncertain.

Our future capital requirements will depend on many factors, including:

• the type, number, scope, progress, expansions, results, costs and timing of our clinical trials;

• preclinical studies for our product candidates or other potential product candidates or indications which we are pursuing or may choose to pursue in the future;

• the outcome, timing and costs of regulatory review of our product candidates;

• the costs and timing of manufacturing for our product candidates, including commercial manufacturing;

• our efforts to enhance operational systems and hire additional personnel to satisfy our obligations as a public company, including enhanced internal controls over financial reporting;

• the costs associated with hiring additional personnel and consultants as our preclinical and clinical activities increase;

• the costs and timing of establishing or securing sales and marketing capabilities if any product candidate is approved;

• our ability to achieve sufficient market acceptance, coverage and adequate reimbursement from third party payors and adequate market share and revenue for any approved products;

• patients’ willingness to pay out-of-pocket for any approved products in the absence of coverage and/or adequate reimbursement from third-party payors;

• the terms and timing of establishing and maintaining collaborations, licenses and other similar arrangements;

• the costs of obtaining, maintaining, defending and enforcing our patent and other intellectual property rights; and

• costs associated with any product candidates, products or technologies that we may in-license or acquire.

Until such time as we can generate significant revenue from sales of our product candidates, if ever, we expect to finance our cash needs through public or private equity or debt financings or other capital sources, including potential collaborations, licenses and other similar arrangements. However, we may be unable to raise additional funds or enter into such other arrangements when needed on favorable terms or at all. To the extent that we raise additional capital through the sale of equity or convertible debt securities, the ownership interest of our stockholders will be or could be diluted, and the terms of these securities may include liquidation or other preferences that adversely affect the rights of our common stockholders. Debt financing and equity financing, if available, may involve agreements that include covenants limiting or restricting our ability to take specific actions, such as incurring additional debt, making capital expenditures or declaring dividends. If we raise funds through collaborations, or other similar arrangements with third parties, we may have to relinquish valuable rights to our product candidates, future revenue streams or research programs or may have to grant licenses on terms that may not be favorable to us and/or may reduce the value of our common stock. If we are unable to raise additional funds through equity or debt financings when needed, we may be required to delay, limit, reduce or terminate our product

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development or future commercialization efforts or grant rights to develop and market our product candidates even if we would otherwise prefer to develop and market such product candidates ourselves.

Contractual Obligations and Commitments

Contract Supply Agreement

In March 2019, we entered into a supply agreement with EirGenix, Inc. (“EirGenix”), pursuant to which EirGenix agreed to supply us, on a non-exclusive basis, bulk drug substance of EG12014, its monoclonal antibody being developed as a biosimilar of trastuzumab, which we use in the manufacture of our BDC-1001 HER2 Boltbody ISAC. Under this agreement, we are required to make milestone payments to EirGenix up to an aggregate of $2.0 million based on achievement of certain regulatory milestones by our HER2 Boltbody ISAC.

License and Collaboration Agreements

In May 2015 and June 2018, we entered into license agreements with Stanford, pursuant to which Stanford granted us worldwide exclusive licenses under certain patents related to our proprietary Boltbody ISAC technology and myeloid modulation for cancer immunotherapy, respectively. Under these agreements, we are obligated to pay annual license maintenance fees, which are nominal and will be creditable against any royalties payable to Stanford under such agreement in the applicable year. We are required in each agreement to make milestone payments up to an aggregate of $0.4 million for the first licensed product under such agreement that meets certain patent issuance, clinical and regulatory milestones, and an additional milestone payment of $0.2 million for each additional regulatory approval. We also agreed in each agreement to pay Stanford tiered royalties on our and our sublicensees’ net sales of licensed products, at low single-digit percentage rates, subject to certain customary reductions. Our royalty obligations continue for the term of each agreement, and we are required to pay royalties on any licensed products made, used, imported or offered for sale during the term of such agreement but sold after the term of the agreement. In addition, we are obligated in each agreement to pay Stanford a sub-teen double digit to low teen double-digit percentage, based on the date of sublicensing, of certain consideration we receive as a result of granting sublicenses to the licensed patents. Pursuant to each agreement, we will reimburse Stanford’s patent expenses, including reasonable costs incurred in assisting us with prosecuting and maintaining licensed patents.

Off-Balance Sheet Arrangements

During the periods presented, we did not have any off-balance sheet arrangements as defined under the rules and regulations of the SEC.

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Item 3. Quantitative and Qualitative Disclosures About Market Risk

We are a smaller reporting company as defined by Rule 12b-2 of the Exchange Act and are not required to provide the information under this item.

Item 4. Controls and Procedures.

Evaluation of Disclosure Controls and Procedures

Based on their evaluation as of June 30, 2021, our management, including our Chief Executive Officer and Chief Financial Officer, has concluded that our disclosure controls and procedures (as defined in Rule 13a-15(e) under the Exchange Act) were not effective to provide reasonable assurance because of the material weakness in our internal control over financial reporting described below.

Material Weakness

A material weakness was identified in our internal control over financial reporting.

A material weakness is a deficiency, or a combination of deficiencies, in internal control over financial reporting, such that there is a reasonable possibility that a material misstatement of our annual or interim financial statements will not be prevented or detected on a timely basis.

We have the following material weakness in our internal control over financial reporting:

• We did not design or maintain an effective control environment commensurate with the financial reporting requirements. Specifically, we lacked a sufficient number of professionals with an appropriate level of accounting knowledge, training and experience to appropriately analyze, record and disclose accounting matters timely and accurately while maintaining appropriate segregation of duties. Without such professionals, we did not design and maintain formal accounting policies, procedures and controls to achieve complete, accurate and timely financial accounting, reporting and disclosures, including controls over the preparation and review of account reconciliations and journal entries.

The above material weakness did not result in a material misstatement of our previously issued financial statements, however, it could result in a misstatement of our account balances or disclosures that would result in a material misstatement of our annual or interim financial statements that would not be prevented or detected.

Remediation Activities

In order to address the material weakness in internal control over financial reporting described above, management, with direction from the Audit Committee, has begun the process of remediation to address control deficiencies that led to the material weakness. Specifically, management has:

• Increased the number of accounting personnel;

• Initiated a comprehensive risk assessment to identify, design and implement control activities; and

• Begun reviewing and enhancing business policies, procedures and related internal controls to standardize business processes.

Management will continue to review and make necessary changes to the overall design of our internal control environment, as well as policies and procedures to improve the overall effectiveness of internal control over financial reporting. The material weakness will not be considered remediated, however, until the applicable controls operate for a sufficient period of time and management has concluded, through testing, that these controls are operating effectively.

Changes in Internal Control over Financial Reporting

There was no change in our internal control over financial reporting during the three months ended June 30, 2021 that has materially affected, or is reasonably likely to materially affect, our internal control over financial reporting.

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PART II OTHER INFORMATION

Item 1. Legal Proceedings.

From time to time, we may become involved in legal proceedings arising in the ordinary course of our business. There are currently no claims or actions pending against us, the ultimate disposition of which we believe could have a material adverse effect on our results of operations, financial condition or cash flows.

Item 1A. Risk Factors.

As of the date of this Quarterly Report on Form 10-Q, there have been no material changes from the risk factors previously disclosed by us in Item 1A of our Annual Report on Form 10-K for the year ended December 31, 2020 that was filed with the SEC on March 31, 2021. Any of such factors could result in a significant or material adverse effect on our result of operations or financial conditions. Additional risk factors not presently known to us or that we currently deem immaterial may also impair our business or results of operations. We may disclose changes to such factors or disclose additional factors from time to time in our future filings with the SEC.

Item 2. Unregistered Sales of Equity Securities and Use of Proceeds

Recent Sales of Unregistered Securities.

During the three months ended June 30, 2021, we issued and sold the following unregistered securities:  

(1) In June 2021, pursuant to a stock purchase agreement, we issued an aggregate of 821,045 shares of our common stock at a purchase price of approximately $18.2694 per share, for aggregate consideration of $15.0 million.

The offers, sales and issuances of the securities described in paragraph (1) above were deemed to be exempt from registration under the Securities Act in reliance on Section 4(a)(2) of the Securities Act and Rule 506 promulgated under Regulation D promulgated thereunder as transactions by an issuer not involving a public offering. The recipients of securities in each of these transactions acquired the securities for investment only and not with a view to or for sale in connection with any distribution thereof and appropriate legends were affixed to the securities issued in these transactions. Each of the recipients of securities in these transactions was an accredited investor within the meaning of Rule 501 of Regulation D under the Securities Act and had adequate access, through employment, business or other relationships, to information about our company. No underwriters were involved in these transactions.

Use of Proceeds

On February 9, 2021, we completed our IPO pursuant to a registration statement on Form S-1 (File No. 333-252136) that was declared effective by the SEC on February 4, 2021 and sold an aggregate of 13,225,000 shares of our common stock, including the exercise in full by the underwriters of their option to purchase 1,725,000 additional shares of our common stock, at a price of $20.00 per share. After deducting underwriting discounts, commissions and offering costs paid by us, the net proceeds from the offering were approximately $242.0 million.

The net proceeds from the offering have been invested according to our approved investment policy in a mix of money market funds and high-quality, fixed income securities with a weighted average maturity of less than 13 months. Our investment policy emphasizes preservation of principal, availability of cash to meet cash flow requirements and maximizing total net returns after satisfying the first two conditions. There has been no material change in the expected use of the net proceeds from our initial public offering as described in our final prospectus filed with the SEC pursuant to Rule 424(b).

Item 3.Defaults Upon Senior Securities

None.

Item 4. Mine Safety Disclosures.

Not applicable.

Item 5. Other Information.

None.

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Item 6. Exhibits The following is a list of Exhibits filed, furnished or incorporated by reference as part of the Quarterly Report on Form 10-Q:

EXHIBIT INDEX

		Incorporated By Reference
Exhibit Number	Description of Exhibit	Form	File No.	Exhibit	Filing Date	Filed Herewith
3.1	Amended and Restated Certificate of Incorporation of the Registrant, as currently in effect.	8-K	001-39988	3.1	2/9/2021
3.2	Amended and Restated Bylaws of the Registrant, as currently in effect.	S-1	333-252136	3.4	1/15/2021
4.1	Reference is made to Exhibits 3.1 and 3.2.
4.2	Form of common stock certificate of the Registrant.	S-1	333-252136	4.1	1/15/2021
4.3	Description of Securities.	10-K	001-39988	4.3	3/31/2021
31.1	Certification of Principal Executive Officer Pursuant to Rules 13a-14(a) and 15d-14(a) under the Securities Exchange Act of 1934, as Adopted Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.					X
31.2	Certification of Principal Financial Officer Pursuant to Rules 13a-14(a) and 15d-14(a) under the Securities Exchange Act of 1934, as Adopted Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.					X
32.1†	Certification of Principal Executive Officer Pursuant to 18 U.S.C. Section 1350, as Adopted Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.					X
32.2†	Certification of Principal Financial Officer Pursuant to 18 U.S.C. Section 1350, as Adopted Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.					X
101.INS	Inline XBRL Instance Document – the instance document does not appear in the Interactive Data File because XBRL tags are embedded within the Inline XBRL document.
101.SCH	Inline XBRL Taxonomy Extension Schema Document
101.CAL	Inline XBRL Taxonomy Extension Calculation Linkbase Document
101.DEF	Inline XBRL Taxonomy Extension Definition Linkbase Document
101.LAB	Inline XBRL Taxonomy Extension Label Linkbase Document
101.PRE	Inline XBRL Taxonomy Extension Presentation Linkbase Document
104	Cover Page Interactive Data File (embedded within the Inline XBRL document)

† The certifications attached as Exhibit 32.1 and Exhibit 32.2 that accompany this Form 10-Q, are deemed furnished and not filed with the Securities and Exchange Commission and are not to be incorporated by reference into any filing of Bolt Biotherapeutics, Inc. under the Securities Act of 1933, as amended, or the Securities Exchange Act of 1934, as amended, whether made before or after the date of this Form 10-Q, irrespective of any general incorporation language contained in such filing.

26

SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Date: August 12, 2021	BOLT BIOTHERAPEUTICS, INC.
	By:	/s/ Randall C. Schatzman, Ph.D.
		Randall C. Schatzman, Ph.D. Chief Executive Officer
		(Principal Executive Officer)
Date: August 12, 2021
	By:	/s/ William P. Quinn
		William P. Quinn Chief Financial Officer (Principal Financial and Accounting Officer)

27

EX-31.1

Exhibit 31.1

CERTIFICATIONS

I, Randall C. Schatzman, Ph.D., certify that:

1.           I have reviewed this Quarterly Report on Form 10-Q of Bolt Biotherapeutics, Inc.;

2.           Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3.           Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

4.           The registrant's other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) for the registrant and have:

a) Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b) Evaluated the effectiveness of the registrant's disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

c) Disclosed in this report any change in the registrant's internal control over financial reporting that occurred during the registrant's most recent fiscal quarter (the registrant's fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant's internal control over financial reporting; and

5.           The registrant's other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant's auditors and the audit committee of the registrant's board of directors (or persons performing the equivalent functions):

a) All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant's ability to record, process, summarize and report financial information; and

b) Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant's internal control over financial reporting.

Date: August 12, 2021	By:	/s/ Randall C. Schatzman, Ph.D.
		Randall C. Schatzman, Ph.D.
		Chief Executive Officer
		(Principal Executive Officer)

EX-31.2

Exhibit 31.2

CERTIFICATIONS

I, William P. Quinn, certify that:

1.           I have reviewed this Quarterly Report on Form 10-Q of Bolt Biotherapeutics, Inc.;

2.           Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3.           Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

4.           The registrant's other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) for the registrant and have:

a) Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b) Evaluated the effectiveness of the registrant's disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

c) Disclosed in this report any change in the registrant's internal control over financial reporting that occurred during the registrant's most recent fiscal quarter (the registrant's fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant's internal control over financial reporting; and

5.           The registrant's other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant's auditors and the audit committee of the registrant's board of directors (or persons performing the equivalent functions):

a) All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant's ability to record, process, summarize and report financial information; and

b) Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant's internal control over financial reporting.

Date: August 12, 2021	By:	/s/ William P. Quinn
		William P. Quinn
		Chief Financial Officer
		(Principal Financial Officer)

EX-32.1

Exhibit 32.1

CERTIFICATIONS

In connection with the Quarterly Report on Form 10-Q of Bolt Biotherapeutics, Inc. (the "Company") for the period ended June 30, 2021 as filed with the Securities and Exchange Commission on the date hereof (the "Report"), the undersigned, Randall C. Schatzman, Ph.D., Chief Executive Officer of the Company, hereby certifies, pursuant to 18 U.S.C. Section 1350, that to his knowledge:

(1)   the Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended; and

(2)   the information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

Date: August 12, 2021	By:	/s/ Randall C. Schatzman, Ph.D.
		Randall C. Schatzman, Ph.D.
		Chief Executive Officer
		(Principal Executive Officer)

EX-32.2

Exhibit 32.2

CERTIFICATION PURSUANT TO 18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report on Form 10-Q of Bolt Biotherapeutics, Inc. (the "Company") for the period ended June 30, 2021 as filed with the Securities and Exchange Commission on the date hereof (the "Report"), the undersigned, William P. Quinn, Chief Financial Officer of the Company, hereby certifies, pursuant to 18 U.S.C. Section 1350, that to his knowledge:

(1)   the Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended; and

(2)   the information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

Date: August 12, 2021	By:	/s/ William P. Quinn
		William P. Quinn
		Chief Financial Officer
		(Principal Financial Officer)

XML

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2021	Aug. 06, 2021
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
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		37,201,444
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

XML

CONDENSED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 58,302	$ 5,542
Short-term investments	186,686	17,296
Prepaid expenses and other current assets	3,163	2,523
Total current assets	248,151	25,361
Property and equipment, net	4,551	4,083
Operating lease right-of-use assets	25,977	12,267
Finance lease right-of-use assets	25	34
Restricted cash	1,565	1,565
Deferred offering costs		2,357
Long-term investments	65,938
Other assets	867	875
Total assets	347,074	46,542
Current liabilities:
Accounts payable	1,614	1,598
Accrued expenses and other current liabilities	10,983	6,663
Deferred revenue	4,330	1,502
Operating lease liabilities	2,323	1,501
Total current liabilities	19,250	11,264
Operating lease liabilities, net of current portion	23,160	9,376
Deferred revenue, non-current	8,535
Convertible preferred stock purchase right liability, non-current		25,224
Other long-term liabilities	233	329
Total liabilities	51,178	46,193
Commitments and contingencies (Note 7)
Convertible preferred stock, $0.00001 par value; 10,000,000 shares and 20,843,367 shares authorized at June 30, 2021 and December 31, 2020, respectively; zero and 15,232,275 shares issued and outstanding at June 30, 2021 and December 31, 2020, respectively.		105,296
Stockholders' equity (deficit):
Additional paid-in capital	452,357	3,452
Accumulated other comprehensive loss	(23)
Accumulated deficit	(156,438)	(108,399)
Total stockholders' equity (deficit):	295,896	(104,947)
Total liabilities, convertible preferred stock, and stockholders' equity (deficit)	$ 347,074	$ 46,542

XML

CONDENSED BALANCE SHEETS (Unaudited) (Parenthetical) - $ / shares	Jun. 30, 2021	Dec. 31, 2020
Statement Of Financial Position [Abstract]
Convertible preferred stock, par value per share	$ 0.00001	$ 0.00001
Convertible preferred stock, shares authorized	10,000,000	20,843,367
Convertible preferred stock, shares issued	0	15,232,275
Convertible preferred stock, shares outstanding	0	15,232,275
Common stock, par value per share	$ 0.00001	$ 0.00001
Common stock, shares authorized	200,000,000	198,000,000
Common stock, shares, issued	37,191,005	2,130,139
Common stock, shares, outstanding	37,191,005	2,130,139

XML

CONDENSED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Income Statement [Abstract]
Collaboration revenue	$ 0	$ 67	$ 0	$ 231
Operating expenses:
Research and development	19,707	9,166	33,834	15,953
General and administrative	4,054	2,011	8,353	4,133
Total operating expense	23,761	11,177	42,187	20,086
Loss from operations	(23,761)	(11,110)	(42,187)	(19,855)
Other income (expense), net
Interest income, net	176	51	232	163
Change in fair value of preferred stock right liability			(6,084)
Total other income (expense), net	176	51	(5,852)	163
Net loss	(23,585)	(11,059)	(48,039)	(19,692)
Net unrealized gain (loss) on marketable securities	41	11	(23)	1
Comprehensive loss	$ (23,544)	$ (11,048)	$ (48,062)	$ (19,691)
Net loss per share, basic and diluted	$ (0.64)	$ (5.29)	$ (1.65)	$ (9.45)
Weighted-average shares outstanding, basic and diluted	36,595,112	2,089,320	29,088,267	2,083,197

XML

CONDENSED STATEMENTS OF CONVERTIBLE 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, 2019	$ (45,846)			$ 1,825		$ (47,671)
Beginning Balance, Shares at Dec. 31, 2019			1,921,642
Beginning Balance at Dec. 31, 2019		$ 77,505
Beginning Balance, Shares at Dec. 31, 2019		10,070,102
Issuance of Series C-1 convertible preferred stock, net of issuance costs of $225 and convertible preferred stock purchase right liability of $13,479		$ 27,851
Issuance of Series C-1 convertible preferred stock, net of issuance costs of $225 and convertible preferred stock purchase right liability of $13,479, Shares		5,162,173
Issuance of common stock upon exercise of stock options	39			39
Issuance of common stock upon exercise of stock options, Shares			17,701
Vesting of early exercised options and restricted stock awards	9			9
Stock-based compensation	448			448
Unrealized gain (loss) on available-for-sale investments	1				$ 1
Net loss	(19,692)					(19,692)
Ending Balance at Jun. 30, 2020	(65,041)			2,321	1	(67,363)
Ending Balance, Shares at Jun. 30, 2020		15,232,275
Ending Balance at Jun. 30, 2020		$ 105,356
Ending Balance, Shares at Jun. 30, 2020			1,939,343
Beginning Balance at Mar. 31, 2020	(54,225)			2,089	(10)	(56,304)
Beginning Balance, Shares at Mar. 31, 2020			1,937,803
Beginning Balance at Mar. 31, 2020		$ 77,505
Beginning Balance, Shares at Mar. 31, 2020		10,070,102
Issuance of Series C-1 convertible preferred stock, net of issuance costs of $225 and convertible preferred stock purchase right liability of $13,479		$ 27,851
Issuance of Series C-1 convertible preferred stock, net of issuance costs of $225 and convertible preferred stock purchase right liability of $13,479, Shares		5,162,173
Issuance of common stock upon exercise of stock options	5			5
Issuance of common stock upon exercise of stock options, Shares			1,540
Vesting of early exercised options and restricted stock awards	4			4
Stock-based compensation	223			223
Unrealized gain (loss) on available-for-sale investments	11				11
Net loss	(11,059)					(11,059)
Ending Balance at Jun. 30, 2020	(65,041)			2,321	1	(67,363)
Ending Balance, Shares at Jun. 30, 2020		15,232,275
Ending Balance at Jun. 30, 2020		$ 105,356
Ending Balance, Shares at Jun. 30, 2020			1,939,343
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	$ 105,296
Beginning Balance, Shares at Dec. 31, 2020	15,232,275	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, Shares		(20,843,334)
Temporary equity, Conversion of convertible preferred stock to common stock		$ (188,506)
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 upon exercise of common stock warrants, Shares			82,603
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	152			152
Issuance of common stock upon exercise of stock options, Shares			59,199
Vesting of early exercised options and restricted stock awards	98			98
Stock-based compensation	4,132			4,132
Unrealized gain (loss) on available-for-sale investments	(23)				(23)
Net loss	(48,039)					(48,039)
Ending Balance at Jun. 30, 2021	$ 295,896			452,357	(23)	(156,438)
Ending Balance, Shares at Jun. 30, 2021	0
Ending Balance, Shares at Jun. 30, 2021			37,191,005
Beginning Balance at Mar. 31, 2021	$ 303,248			436,165	(64)	(132,853)
Beginning Balance, Shares at Mar. 31, 2021			36,331,846
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	23			23
Issuance of common stock upon exercise of stock options, Shares			8,429
Vesting of early exercised options and restricted stock awards	88			88
Stock-based compensation	2,023			2,023
Unrealized gain (loss) on available-for-sale investments	41				41
Net loss	(23,585)					(23,585)
Ending Balance at Jun. 30, 2021	$ 295,896			$ 452,357	$ (23)	$ (156,438)
Ending Balance, Shares at Jun. 30, 2021	0
Ending Balance, Shares at Jun. 30, 2021			37,191,005

XML

CONDENSED STATEMENTS OF CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Common Stock
Stock issuance cost		$ 22,541
Convertible Preferred Stock
Stock issuance cost		$ 42
Purchase right liability	$ 13,479		$ 13,479
Series C-1 Convertible Preferred Stock
Stock issuance cost	$ 225		$ 225

XML

CONDENSED STATEMENTS OF CASH FLOWS (Unaudited) $ in Thousands	6 Months Ended
	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (48,039)	$ (19,692)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	528	211
Stock-based compensation expense	4,132	448
Accretion of premium/discount on marketable securities	1,034	(53)
Unrealized gain (loss) on marketable securities, net	(23)	1
Change in fair value of convertible preferred stock purchase rights liabilities	6,084
Non-cash lease expense	1,174	885
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(632)	(382)
Accounts payable and accrued expenses	4,110	(438)
Operating lease liabilities	(278)	(2,821)
Deferred revenue	11,363	(69)
Other long-term liabilities	2	7
Net cash used in operating activities	(20,545)	(21,903)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of property and equipment	(761)	(1,213)
Purchases of marketable securities	(247,768)	(13,235)
Maturities of marketable securities	11,406	5,247
Net cash used in investing activities	(237,123)	(9,201)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of preferred stock, net of issuance cost	51,902	41,546
Proceeds from initial public offering, net of issuance cost	244,316
Proceeds from issuance of common stock related to stock purchase agreement	13,638
Proceeds from issuance of common stock	572	39
Net cash provided by financing activities	310,428	41,585
Net increase in cash	52,760	10,481
Cash, cash equivalents and restricted cash at beginning of year	7,107	35,410
Cash, cash equivalents and restricted cash at end of period	59,867	45,891
Reconciliation of cash, cash equivalents and restricted cash:
Cash and cash equivalents	58,302	45,307
Restricted cash	1,565	584
Total cash, cash equivalents and restricted cash	59,867	45,891
Supplemental schedule of non-cash investing and financing activities:
Vesting of early exercised options	98	9
Purchases of property and equipment included in accounts payable and accrued liabilities	226	280
Deferred offering costs in accounts payable and accrued liabilities		216
Right of use assets obtained in exchange for operating lease obligations	$ 14,884	$ 324

XML

Description of the Business

6 Months Ended

Jun. 30, 2021

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 biotechnology company pioneering a new class of immuno-oncology agents that combine the targeting precision of antibodies with the power of both the innate and adaptive immune systems.

Initial Public Offering and Related Transactions

On February 9, 2021, the Company completed its initial public offering (“IPO”) pursuant to a registration statement on Form S-1 (File No. 333-252136) that was declared effective by the Securities and Exchange Commission (the “SEC”) on February 4, 2021, and sold an aggregate of 13,225,000 shares of its common stock, including the full exercise of the underwriters’ option to purchase 1,725,000 shares, at a price per share of $20.00. Proceeds from the IPO, net of underwriting discounts, commissions and offering costs, were approximately $242.0 million.

In addition, each of the following occurred on February 4, 2021, in connection with the completion of the Company’s IPO:

• the conversion of all outstanding shares of convertible preferred stock into 20,843,334 shares of the Company’s common stock; and

• the amendment and restatement of the Company’s certificate of incorporation, authorizing 200,000,000 shares of common stock and 10,000,000 shares of undesignated preferred stock.  

XML

Summary of Significant Accounting Policies

6 Months Ended

Jun. 30, 2021

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 June 30, 2021 and for the three and six months ended June 30, 2021 and 2020 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 fairly state the Company’s financial position and the results of its operations and cash flows. The balance sheet as of December 31, 2020 was derived from the audited financial statements as of that date. 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, 2020.

Reverse Stock Split

On January 26, 2021, the Company amended and restated its amended and restated certificate of incorporation to effect a 1-for-7 reverse stock split of the Company’s outstanding common stock and convertible preferred stock. The par value and authorized shares of the common stock were not adjusted as a result of the reverse stock split. All issued and outstanding common stock, options to purchase common stock, early exercised options and per share amounts contained in the financial statements have been retroactively adjusted to give effect to the reverse stock split for all periods presented.

Other Risks and Uncertainties

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 and 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 current COVID-19 pandemic, protection of intellectual property rights, litigation or claims against the Company based on intellectual property rights, regulatory clearance and market acceptance of the Company’s products. 

The current COVID-19 pandemic, which is impacting worldwide economic activity, poses the risk that the Company or its employees, contractors, suppliers and other partners may be prevented from conducting business activities for an indefinite period of time, including due to shutdowns that may be requested or mandated by governmental authorities. The extent to which the COVID-19 pandemic will impact the Company’s business will depend on future developments that are highly uncertain and cannot be predicted at this time. The preparation of financial statements in conformity with generally accepted accounting principles requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. The extent to which the COVID-19 pandemic may directly or indirectly impact the Company’s financial statements is highly uncertain and subject to change. Management considered the potential impact of the COVID-19 pandemic on its estimates and assumptions and there was not a material impact to the Company’s condensed financial statements as of and for the three and six months ended June 30, 2021; however, actual results could differ from those estimates and there may be changes to management’s estimates in future periods.

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.

Use of Estimates

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. On an ongoing basis, the Company evaluates its estimates and assumptions, including those related to revenue recognition, the valuation of common stock, stock-based compensation, convertible preferred stock purchase right liabilities 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.

Deferred Offering Costs

The Company capitalized certain legal, accounting and other third-party fees that were directly related to the Company’s IPO. After the completion of the IPO in February 2021, the total deferred offering costs of $4.0 million were offset against the proceeds from the IPO and reclassified to additional paid-in capital in the accompanying the balance sheets. At December 31, 2020, deferred offering costs totaling $2.4 million were included as non-current assets in the accompanying balance sheet.

Concentrations of Credit Risk

Financial instruments that potentially subject the Company to concentration of credit risk consist of cash, cash equivalents and marketable securities. At June 30, 2021 and December 31, 2020, most of the Company’s funds are invested with a registered investment manager and custodied at one financial institution, with working capital 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 June 30, 2021 and December 31, 2020, 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. 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 June 30, 2021 and December 31, 2020, 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 our 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 to be 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 six months ended June 30, 2021 that are of significance to the Company’s financial position or results of operations.

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Fair Value Measurements and Fair Value of Financial Instruments

6 Months Ended

Jun. 30, 2021

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 not active or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.

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 six months ended June 30, 2021, 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. Financial liabilities measured at fair value on a recurring basis include the convertible preferred stock purchase rights liabilities described below.

There were no transfers within the hierarchy during the three and six months ended June 30, 2021 and 2020.

Marketable securities, all of which are classified as available-for-sale securities, consisted of the following at June 30, 2021 and December 31, 2020 (in thousands):

	June 30, 2021
	Amortized		Unrealized		Unrealized			Estimated
	Cost		Gains		Losses			Fair Value
Asset-backed securities	$	38,644	$	3	$	(6	)	$	38,641
U.S. treasury securities		29,993		—		(12	)		29,981
Other government agency securities		5,098		—		(5	)		5,093
Commercial paper		90,819		—		—			90,819
Corporate debt securities		88,092		16		(18	)		88,090
Total	$	252,646	$	19	$	(41	)	$	252,624

	December 31, 2020
	Amortized		Unrealized		Unrealized			Estimated
	Cost		Gains		Losses			Fair Value
Asset-backed securities	$	2,639	$	—	$	—		$	2,639
U.S. treasury securities		1,300		—		—			1,300
Commercial paper		6,795		—		—			6,795
Corporate debt securities		6,562		1		(1	)		6,562
Total	$	17,296	$	1	$	(1	)	$	17,296

At June 30, 2021 and December 31, 2020, the fair values of the Company’s assets and liabilities, which are measured at fair value on a recurring basis, were determined using the following inputs (in thousands):

	June 30, 2021
	Total		(Level 1)		(Level 2)		(Level 3)
Money market funds	$	54,700	$	54,700	$	—	$	—
Asset-backed securities		38,641		—		38,641		—
U.S. treasury securities		29,981		—		29,981		—
Other government agency securities		5,093		—		5,093		—
Commercial paper		90,819		—		90,819		—
Corporate debt securities		88,090		—		88,090		—
Total	$	307,324	$	54,700	$	252,624	$	—

	December 31, 2020
	Total		(Level 1)		(Level 2)		(Level 3)
Money market funds	$	3,921	$	3,921	$	—	$	—
Asset-backed securities		2,640		—		2,640		—
U.S. treasury securities		1,300		1,300		—		—
Commercial paper		6,795		—		6,795		—
Corporate debt securities		6,561		—		6,561		—
Total	$	21,217	$	5,221	$	15,996	$	—
Liabilities:
Preferred stock purchase rights liability	$	25,224	$	—	$	—	$	25,224

Level 3 liabilities that are measured at fair value on a recurring basis consist of the convertible preferred stock purchase right liabilities. The following table provides a summary of changes in the estimated fair value of the financial instruments using significant Level 3 inputs (in thousands):

	Series C Convertible Preferred Stock Purchase Right Liability
Balance at December 31, 2020	$	25,224
Change in fair value		6,084
Reclassification to equity		(31,308	)
Balance at June 30, 2021	$	—

The fair value of the convertible preferred stock purchase right liabilities is estimated using an income-based approach incorporating probability considerations for different scenarios. The main assumptions include the probability and timing of the tranche closing, and the estimated value of the Company’s equity at that time. In January 2021, the Company issued the additional shares of Series C-2 convertible preferred stock and accordingly, this contractual obligation was settled, and the preferred stock purchase right liability was remeasured to its fair value and reclassified to permanent equity. The fair value of the convertible preferred stock purchase right liability immediately prior to settlement was increased to $31.3 million as a result of the estimated probability of the occurrence of the second closing of Series C convertible preferred stock increasing to 80%, timing related to the occurrence of the second closing decreasing to 0.06 years and the increase in the future expected value of the Series C preferred shares to $16.25 per share.

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License and Equity Agreement

6 Months Ended

Jun. 30, 2021

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 (the “Stanford Agreement”), as amended, 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. 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.

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Balance Sheet Components

6 Months Ended

Jun. 30, 2021

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):

	June 30, 2021			December 31, 2020
Laboratory equipment	$	6,028		$	5,253
Leasehold Improvements		67			—
Office equipment		214			69
Total property and equipment		6,309			5,322
Less accumulated depreciation and amortization		(1,758	)		(1,239	)
Total	$	4,551		$	4,083

Depreciation expense related to property and equipment was $0.2 million and $0.5 million for the three and six months ended June 30, 2021, respectively, and $0.1 million and $0.2 million for the same periods in 2020, respectively.

Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consist of the following (in thousands):

	June 30, 2021		December 31, 2020
Accrued research and development	$	7,054	$	3,199
Accrued compensation		2,414		2,885
Accrued other		1,515		579
Total	$	10,983	$	6,663

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Collaborations

6 Months Ended

Jun. 30, 2021

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 Development 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 Development Agreement is a contract with a customer and should be accounted for under ASC 606. In conjunction with the Toray Development 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 Development agreement and included in the total consideration for collaboration revenue. In February 2021, in connection with the Company’s IPO, all outstanding shares of Series T convertible preferred stock were converted into shares of the Company’s common stock.

In the Toray Development 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, which is expected to take place through the first half of 2022. As of June 30, 2021 and December 31, 2020, contract liabilities totaling $1.5 million at each period-end were recorded in deferred revenue in current liabilities on the balance sheet. The Toray Development Agreement includes 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 Bolt’s 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, Bolt received an upfront payment of $10.0 million and is eligible to receive total potential milestone payments of up to $285.0 million per therapeutic candidate exclusively developed and commercialized by Genmab, along with tiered royalties at rates from a mid-single digit to mid-teens percentage, subject to certain customary reductions. 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 “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 $6.1 million of estimated variable consideration related to reimbursements 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 June 30, 2021, contract liabilities totaling $11.4 million was recorded in deferred revenue in current and non-current liabilities on the balance sheet. There was no revenue earned during the three and six months ended June 30, 2021, as no services had been performed under the Genmab Agreement during these periods. 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 and the parties exercise their respective program opt in rights.

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Commitment and Contingencies

6 Months Ended

Jun. 30, 2021

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 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. As of June 30, 2021, the operating lease right-of-use assets and operating lease liabilities for the 45,690 square feet of additional space were $18.5 million and $19.2 million, respectively.

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 will expire on July 31, 2022. The second sublease agreement, to sublease 10,500 square feet, commenced in June 2021 and will expire on July 31, 2023. Rent for both subleases are subject to scheduled annual increases and the subtenants are responsible for certain operating expenses and taxes throughout the term under the sublease agreements. The subtenants have no option to extend the sublease term. Sublease income under the two sublease agreements for the three and six months ended June 30, 2021, was approximately $0.2 million and $0.3 million, respectively.

At June 30, 2021 and December 31, 2020, finance right-of-use leases are used to finance capital equipment such as printers or ozone generators and it is immaterial.

The weighted-average remaining lease term and discount rate related to the Company’s lease liabilities as of June 30, 2021 were 8.4 years and 10.8%, 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, 2020 were 6.3 years and 9.5%, 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 June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Total operating lease cost	$	902	$	603	$	1,669	$	1,196

Supplemental cash flow information related to leases was as follows (in thousands):

	Six Months Ended June 30,
	2021		2020
Operating cash flows from operating leases	$	666	$	3,133

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 June 30, 2021 (in thousands):

	Operating Leases			Sublease Income
2021	$	2,446		$	646
2022		4,994			1,048
2023		4,612			403
2024		4,772			—
2025		4,227			—
Thereafter		19,709			—
Total minimum lease payments/sublease income		40,760			2,097
Less imputed interest		(15,277	)		—
Total	$	25,483		$	2,097

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 June 30, 2021, 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 June 30, 2021, 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.

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Convertible Preferred Stock

6 Months Ended

Jun. 30, 2021

Equity [Abstract]

Convertible Preferred Stock

8. Convertible Preferred Stock

Issuance of Series C-1 and Series C-2 Convertible Preferred Stock

In June 2020, the Company entered into a preferred stock purchase agreement (the “Series C Agreement”) with existing and new investors to raise up to $93.5 million in two separate tranches. The first tranche closed in June 2020 and the Company raised $41.3 million, net of issuance costs of $0.2 million, and issued 5,162,173 shares of Series C-1 convertible preferred stock at $8.05 per share. In addition, the investors agreed to buy and the Company agreed to sell up to 5,611,065 shares of Series C-2 convertible

preferred stock at a price per share of $9.2575, for potential additional gross proceeds of $51.9 million, upon the achievement of certain milestones as defined in the agreement.

The commitment made by the investors to invest in the second tranche of the Series C Agreement was considered a separate freestanding financial instrument and was recorded as a Convertible Preferred Stock Purchase Right Liability in the amount of $13.5 million upon the issuance of the first tranche of the Series C-1 convertible preferred stock in June 2020. The commitment was accounted for at fair value during the period it was outstanding with changes in fair value recorded as other income (expense) in the statement of operations and comprehensive loss. During the three months ended March 31, 2021, changes in fair value of this liability totaling $6.1 million have been recorded in other income (expense) in the statement of operations and comprehensive loss. In January 2021, the Company issued the additional 5,611,059 shares of Series C-2 convertible preferred stock for net proceeds of $51.9 million and accordingly, this contractual obligation was settled and the preferred stock purchase right liability was remeasured to its fair value and reclassified to permanent equity. In February 2021, all outstanding shares of convertible preferred stock were converted into the Company’s common stock in connection with the IPO.

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Common Stock

6 Months Ended

Jun. 30, 2021

Equity [Abstract]

Common Stock

9. COMMON STOCK

Common Stock Warrants

In July 2018, the Company issued 249,218 warrants to purchase common stock to the Series B investors in the first tranche. The warrants were deemed to be freestanding instruments indexed to the Company’s common stock and met the requirements for equity classification. The warrants had an expiration date of July 26, 2028 and were exercisable at the option of the warrant holder for $0.07 per share. In February 2021, all outstanding warrants were exercised to purchase 82,603 shares of the Company’s common stock in connection with the IPO.

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Stock-Based Compensation

6 Months Ended

Jun. 30, 2021

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-Based Compensation

10. STOCK-BASED COMPENSATION

Approval of 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, 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. During the three and six months ended June 30, 2021, 29,685 shares had been issued under the 2021 ESPP.

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 $0.6 million for the three and six months ended June 30, 2021, respectively. The weighted-average grant date fair value of the Performance Awards was $3.24 per share. 

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 June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Research and development	$	1,077	$	98	$	2,097	$	198
General and administrative		946		125		2,035		250
Total	$	2,023	$	223	$	4,132	$	448

Early Exercise Liability

Some of the options granted under the 2015 Plan may be exercised prior to the time that the options have vested, provided that such shares remain subject to repurchase until such time as they have vested. The right to repurchase these shares lapses over the vesting periods, which are generally four years. As of June 30, 2021 and December 31, 2020, there were 10,904 and 47,180, respectively, unvested shares representing an early exercise liability of approximately $28,000 and $0.1 million, respectively. The unvested shares purchased by the employees are not deemed, for accounting purposes, to be outstanding.

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Net Loss Per Share

6 Months Ended

Jun. 30, 2021

Earnings Per Share [Abstract]

Net Loss Per Share

11. 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 June 30,						Six Months Ended June 30,
	2021			2020			2021			2020
Numerator:
Net loss	$	(23,585	)	$	(11,059	)	$	(48,039	)	$	(19,692	)
Denominator:
Weighted average common shares outstanding		36,617,390			1,937,510			29,104,021			1,935,575
Weighted average common stock outstanding subject to repurchase related to unvested early exercised stock options and restricted stock awards		(22,279	)		(20,213	)		(33,553	)		(24,401	)
Weighted average warrants to purchase common stock		—			172,023			17,798			172,023
Weighted average common shares outstanding - basic and    diluted		36,595,112			2,089,320			29,088,267			2,083,197
Net loss per share attributable to common stockholders, basic    and diluted	$	(0.64	)	$	(5.29	)	$	(1.65	)	$	(9.45	)

Potentially 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):

	Three and Six Months Ended
	2021		2020
Convertible preferred stock		—		15,232,275
Common stock options issued and outstanding		5,091,714		1,992,801
Common stock outstanding subject to repurchase related to    unvested early exercised stock options and restricted    stock awards		10,904		16,132
Total		5,102,618		17,241,208

The ESPP did not exist in 2020, and the potentially dilutive shares to be issued under the ESPP as of June 30, 2021 were not included in the calculation of dilutive net loss per share because they would be anti-dilutive and were immaterial.

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Summary of Significant Accounting Policies (Policies)

6 Months Ended

Jun. 30, 2021

Accounting Policies [Abstract]

Basis of Presentation

Basis of Presentation

The accompanying unaudited condensed financial statements as of June 30, 2021 and for the three and six months ended June 30, 2021 and 2020 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 fairly state the Company’s financial position and the results of its operations and cash flows. The balance sheet as of December 31, 2020 was derived from the audited financial statements as of that date. 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, 2020.

Reverse Stock Split

Reverse Stock Split

On January 26, 2021, the Company amended and restated its amended and restated certificate of incorporation to effect a 1-for-7 reverse stock split of the Company’s outstanding common stock and convertible preferred stock. The par value and authorized shares of the common stock were not adjusted as a result of the reverse stock split. All issued and outstanding common stock, options to purchase common stock, early exercised options and per share amounts contained in the financial statements have been retroactively adjusted to give effect to the reverse stock split for all periods presented.

Other Risks and Uncertainties

Other Risks and Uncertainties

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 and 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 current COVID-19 pandemic, protection of intellectual property rights, litigation or claims against the Company based on intellectual property rights, regulatory clearance and market acceptance of the Company’s products. 

The current COVID-19 pandemic, which is impacting worldwide economic activity, poses the risk that the Company or its employees, contractors, suppliers and other partners may be prevented from conducting business activities for an indefinite period of time, including due to shutdowns that may be requested or mandated by governmental authorities. The extent to which the COVID-19 pandemic will impact the Company’s business will depend on future developments that are highly uncertain and cannot be predicted at this time. The preparation of financial statements in conformity with generally accepted accounting principles requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. The extent to which the COVID-19 pandemic may directly or indirectly impact the Company’s financial statements is highly uncertain and subject to change. Management considered the potential impact of the COVID-19 pandemic on its estimates and assumptions and there was not a material impact to the Company’s condensed financial statements as of and for the three and six months ended June 30, 2021; however, actual results could differ from those estimates and there may be changes to management’s estimates in future periods.

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.

Use of Estimates

Use of Estimates

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. On an ongoing basis, the Company evaluates its estimates and assumptions, including those related to revenue recognition, the valuation of common stock, stock-based compensation, convertible preferred stock purchase right liabilities 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.

Deferred Offering Costs

Deferred Offering Costs

The Company capitalized certain legal, accounting and other third-party fees that were directly related to the Company’s IPO. After the completion of the IPO in February 2021, the total deferred offering costs of $4.0 million were offset against the proceeds from the IPO and reclassified to additional paid-in capital in the accompanying the balance sheets. At December 31, 2020, deferred offering costs totaling $2.4 million were included as non-current assets in the accompanying balance sheet.

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. At June 30, 2021 and December 31, 2020, most of the Company’s funds are invested with a registered investment manager and custodied at one financial institution, with working capital 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 June 30, 2021 and December 31, 2020, 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. 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 June 30, 2021 and December 31, 2020, 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 our 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 to be 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 six months ended June 30, 2021 that are of significance to the Company’s financial position or results of operations.

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Fair Value Measurements and Fair Value of Financial Instruments (Tables)

6 Months Ended

Jun. 30, 2021

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 June 30, 2021 and December 31, 2020 (in thousands):

	June 30, 2021
	Amortized		Unrealized		Unrealized			Estimated
	Cost		Gains		Losses			Fair Value
Asset-backed securities	$	38,644	$	3	$	(6	)	$	38,641
U.S. treasury securities		29,993		—		(12	)		29,981
Other government agency securities		5,098		—		(5	)		5,093
Commercial paper		90,819		—		—			90,819
Corporate debt securities		88,092		16		(18	)		88,090
Total	$	252,646	$	19	$	(41	)	$	252,624

	December 31, 2020
	Amortized		Unrealized		Unrealized			Estimated
	Cost		Gains		Losses			Fair Value
Asset-backed securities	$	2,639	$	—	$	—		$	2,639
U.S. treasury securities		1,300		—		—			1,300
Commercial paper		6,795		—		—			6,795
Corporate debt securities		6,562		1		(1	)		6,562
Total	$	17,296	$	1	$	(1	)	$	17,296

Schedule of Fair Values of Assets and Liabilities Measured at Fair Value on Recurring Basis

At June 30, 2021 and December 31, 2020, the fair values of the Company’s assets and liabilities, which are measured at fair value on a recurring basis, were determined using the following inputs (in thousands):

	June 30, 2021
	Total		(Level 1)		(Level 2)		(Level 3)
Money market funds	$	54,700	$	54,700	$	—	$	—
Asset-backed securities		38,641		—		38,641		—
U.S. treasury securities		29,981		—		29,981		—
Other government agency securities		5,093		—		5,093		—
Commercial paper		90,819		—		90,819		—
Corporate debt securities		88,090		—		88,090		—
Total	$	307,324	$	54,700	$	252,624	$	—

	December 31, 2020
	Total		(Level 1)		(Level 2)		(Level 3)
Money market funds	$	3,921	$	3,921	$	—	$	—
Asset-backed securities		2,640		—		2,640		—
U.S. treasury securities		1,300		1,300		—		—
Commercial paper		6,795		—		6,795		—
Corporate debt securities		6,561		—		6,561		—
Total	$	21,217	$	5,221	$	15,996	$	—
Liabilities:
Preferred stock purchase rights liability	$	25,224	$	—	$	—	$	25,224

Schedule of Changes in Estimated Fair Value of Financial Instruments

The following table provides a summary of changes in the estimated fair value of the financial instruments using significant Level 3 inputs (in thousands):

	Series C Convertible Preferred Stock Purchase Right Liability
Balance at December 31, 2020	$	25,224
Change in fair value		6,084
Reclassification to equity		(31,308	)
Balance at June 30, 2021	$	—

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Balance Sheet Components (Tables)

6 Months Ended

Jun. 30, 2021

Balance Sheet Related Disclosures [Abstract]

Property and Equipment, Net

Property and equipment, net, consist of the following (in thousands):

	June 30, 2021			December 31, 2020
Laboratory equipment	$	6,028		$	5,253
Leasehold Improvements		67			—
Office equipment		214			69
Total property and equipment		6,309			5,322
Less accumulated depreciation and amortization		(1,758	)		(1,239	)
Total	$	4,551		$	4,083

Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consist of the following (in thousands):

	June 30, 2021		December 31, 2020
Accrued research and development	$	7,054	$	3,199
Accrued compensation		2,414		2,885
Accrued other		1,515		579
Total	$	10,983	$	6,663

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Commitment and Contingencies (Tables)

6 Months Ended

Jun. 30, 2021

Commitments And Contingencies Disclosure [Abstract]

Components of Lease Expense

The components of lease expense were as follows (in thousands):

	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Total operating lease cost	$	902	$	603	$	1,669	$	1,196

Supplemental Cash Flow Information Related to Leases

Supplemental cash flow information related to leases was as follows (in thousands):

	Six Months Ended June 30,
	2021		2020
Operating cash flows from operating leases	$	666	$	3,133

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 June 30, 2021 (in thousands):

	Operating Leases			Sublease Income
2021	$	2,446		$	646
2022		4,994			1,048
2023		4,612			403
2024		4,772			—
2025		4,227			—
Thereafter		19,709			—
Total minimum lease payments/sublease income		40,760			2,097
Less imputed interest		(15,277	)		—
Total	$	25,483		$	2,097

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Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2021

Disclosure Of Compensation Related Costs Sharebased Payments [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 June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Research and development	$	1,077	$	98	$	2,097	$	198
General and administrative		946		125		2,035		250
Total	$	2,023	$	223	$	4,132	$	448

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Net Loss Per Share (Tables)

6 Months Ended

Jun. 30, 2021

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 June 30,						Six Months Ended June 30,
	2021			2020			2021			2020
Numerator:
Net loss	$	(23,585	)	$	(11,059	)	$	(48,039	)	$	(19,692	)
Denominator:
Weighted average common shares outstanding		36,617,390			1,937,510			29,104,021			1,935,575
Weighted average common stock outstanding subject to repurchase related to unvested early exercised stock options and restricted stock awards		(22,279	)		(20,213	)		(33,553	)		(24,401	)
Weighted average warrants to purchase common stock		—			172,023			17,798			172,023
Weighted average common shares outstanding - basic and    diluted		36,595,112			2,089,320			29,088,267			2,083,197
Net loss per share attributable to common stockholders, basic    and diluted	$	(0.64	)	$	(5.29	)	$	(1.65	)	$	(9.45	)

Potentially Dilutive Securities not Included in the Calculation of Diluted Net Loss per Share

Potentially 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):

	Three and Six Months Ended
	2021		2020
Convertible preferred stock		—		15,232,275
Common stock options issued and outstanding		5,091,714		1,992,801
Common stock outstanding subject to repurchase related to    unvested early exercised stock options and restricted    stock awards		10,904		16,132
Total		5,102,618		17,241,208

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Description of the Business - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands			6 Months Ended
	Feb. 09, 2021	Feb. 04, 2021	Jun. 30, 2021	Dec. 31, 2020
Subsidiary Sale Of Stock [Line Items]
Proceeds from stock sold, net of underwriting discounts, commissions and offering costs			$ 244,316
Common stock, shares authorized		200,000,000	200,000,000	198,000,000
Preferred stock, shares authorized		10,000,000
Common Stock
Subsidiary Sale Of Stock [Line Items]
Aggregate stock sold			13,225,000
Outstanding shares of convertible preferred stock converted into common stock		20,843,334	20,843,334
IPO | Common Stock
Subsidiary Sale Of Stock [Line Items]
Aggregate stock sold	13,225,000
Sale of stock, price per share	$ 20.00
Proceeds from stock sold, net of underwriting discounts, commissions and offering costs	$ 242,000
Underwriters’ Option | Common Stock
Subsidiary Sale Of Stock [Line Items]
Aggregate stock sold	1,725,000

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Summary of Significant Accounting Policies - Additional Information (Details) $ in Thousands		6 Months Ended
	Jan. 26, 2021	Jun. 30, 2021 USD ($)	Feb. 28, 2021 USD ($)	Dec. 31, 2020 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Deferred offering costs noncurrent				$ 2,400
Deferred offering costs to offset against proceeds from IPO			$ 4,000
Restricted cash		$ 1,565		$ 1,565
Common Stock and Convertible Preferred Stock
Summary Of Significant Accounting Policies [Line Items]
Reverse stock split		1-for-7
Reverse stock split ratio	0.142857

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Fair Value Measurements and Fair Value of Financial Instruments - Additional Information (Details) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended
	Jan. 31, 2021	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value, assets, level 1 to level 2 transfers		$ 0	$ 0	$ 0	$ 0
Fair value, assets, level 2 to level 1 transfers		0	0	0	0
Fair value, liabilities, level 1 to level 2 transfers		0	0	0	0
Fair value, liabilities, level 2 to level 1 transfers		0	0	0	0
Fair value, asset, transfers into level 3		0	0	0	0
Fair value, asset, transfers out of level 3		0	0	0	0
Fair value, liability, transfers into level 3		0	0	0	0
Fair value, liability, transfers out of level 3		$ 0	$ 0	$ 0	$ 0
Series C-2 Convertible Preferred Stock
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of convertible preferred stock purchase right liability	$ 31,300,000
Percentage of increase in convertible preferred stock	80.00%
Period of timing related to occurrence	21 days
Increase in future expected value of share	$ 16.25

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Fair Value Measurements and Fair Value of Financial Instruments - Schedule of Marketable Securities Classified as Available-for-sale Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	$ 252,646	$ 17,296
Unrealized Gains	19	1
Unrealized Losses	(41)	(1)
Estimated Fair Value	252,624	17,296
Asset Backed Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	38,644	2,639
Unrealized Gains	3
Unrealized Losses	(6)
Estimated Fair Value	38,641	2,639
U.S. Treasury Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	29,993	1,300
Unrealized Losses	(12)
Estimated Fair Value	29,981	1,300
Other Government Agency Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	5,098
Unrealized Losses	(5)
Estimated Fair Value	5,093
Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	90,819	6,795
Estimated Fair Value	90,819	6,795
Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized Cost	88,092	6,562
Unrealized Gains	16	1
Unrealized Losses	(18)	(1)
Estimated Fair Value	$ 88,090	$ 6,562

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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	Jun. 30, 2021	Dec. 31, 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total asset	$ 307,324	$ 21,217
Liabilities:
Preferred stock purchase rights liability		25,224
Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total asset	54,700	3,921
Asset Backed Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total asset	38,641	2,640
U.S. Treasury Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total asset	29,981	1,300
Other Government Agency Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total asset	5,093
Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total asset	90,819	6,795
Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total asset	88,090	6,561
Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total asset	54,700	5,221
Level 1 | Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total asset	54,700	3,921
Level 1 | U.S. Treasury Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total asset		1,300
Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total asset	252,624	15,996
Level 2 | Asset Backed Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total asset	38,641	2,640
Level 2 | U.S. Treasury Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total asset	29,981
Level 2 | Other Government Agency Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total asset	5,093
Level 2 | Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total asset	90,819	6,795
Level 2 | Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total asset	$ 88,090	6,561
Level 3
Liabilities:
Preferred stock purchase rights liability		$ 25,224

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Fair Value Measurements and Fair Value of Financial Instruments - Schedule of Changes in Estimated Fair Value of Financial Instruments (Details) - Recurring Basis $ in Thousands	6 Months Ended
	Jun. 30, 2021 USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Balance at December 31, 2020	$ 25,224
Change in fair value	6,084
Reclassification to equity	$ (31,308)

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License and Equity Agreement - Additional Information (Details) - Stanford Agreement	74 Months Ended
	Jun. 30, 2021 USD ($)
License And Equity Agreement [Line Items]
Additional milestone payment	$ 200,000
Royalty payments	0
Maximum
License And Equity Agreement [Line Items]
Aggregate millstone payments	$ 400,000

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Balance Sheet Components - Property and Equipment, Net (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 6,309	$ 5,322
Less accumulated depreciation and amortization	(1,758)	(1,239)
Total	4,551	4,083
Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	6,028	5,253
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	67
Office Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 214	$ 69

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Balance Sheet Components - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Balance Sheet Related Disclosures [Abstract]
Depreciation expense	$ 0.2	$ 0.1	$ 0.5	$ 0.2

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Balance Sheet Components - Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Balance Sheet Related Disclosures [Abstract]
Accrued research and development	$ 7,054	$ 3,199
Accrued compensation	2,414	2,885
Accrued other	1,515	579
Total	$ 10,983	$ 6,663

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Collaborations - Additional Information (Details) - USD ($)	1 Months Ended		3 Months Ended		6 Months Ended
	May 31, 2021	Mar. 31, 2019	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Consideration in excess of fair value					$ 241,959,000
Collaboration revenue			$ 0	$ 67,000	$ 0	$ 231,000
Common Stock
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Issuance of shares					13,225,000
Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Potential future milestone payments					$ 2,000,000.0
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			$ 11,400,000		$ 11,400,000
Upfront payment received	$ 10,000,000.0
Allocated from Genmab SPA	1,400,000
Variable consideration related to reimbursements for research and development services	$ 6,100,000
Genmab Agreement | Common Stock
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Issuance of shares	821,045
Consideration in excess of fair value	$ 1,400,000
Purchase price under Stock Purchase Agreement	15,000,000.0
Genmab Agreement | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Potential future milestone payments	$ 285,000,000.0
Series T Convertible Preferred Stock | Toray Development Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Issuance of shares		717,514
Consideration in excess of fair value		$ 1,500,000

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Commitments and Contingencies - Additional Information (Details)		1 Months Ended	3 Months Ended	6 Months Ended
	Aug. 07, 2020 USD ($) ft²	Jun. 30, 2021 USD ($) ft²	Jun. 30, 2021 USD ($)	Jun. 30, 2021 USD ($) ft²	Dec. 31, 2020 USD ($)
Commitments And Contingencies [Line Items]
Operating lease right-of-use assets		$ 25,977,000	$ 25,977,000	$ 25,977,000	$ 12,267,000
Operating lease liabilities		$ 25,483,000	$ 25,483,000	25,483,000
Sublease income				$ 2,097,000
Weighted-average remaining lease term		8 years 4 months 24 days	8 years 4 months 24 days	8 years 4 months 24 days	6 years 3 months 18 days
Weighted-average discount rate		10.80%	10.80%	10.80%	9.50%
Maximum
Commitments And Contingencies [Line Items]
Potential future milestone payments				$ 2,000,000.0
Chesapeake Master Lease
Commitments And Contingencies [Line Items]
Operating lease, area of property available | ft²	71,646
Operating lease, area of property, additional space available | ft²	45,690			45,690
Operating lease, area of property, extension space available | ft²	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 | ft²	10,000
Operating lease, area of property, additional space remaining | ft²		35,690
Operating lease right-of-use assets		$ 18,500,000	$ 18,500,000	$ 18,500,000
Operating lease liabilities		$ 19,200,000	19,200,000	$ 19,200,000
Sublease, area of property leased | ft²	10,000
Sublease expiration date	Jul. 31, 2022			Jul. 31, 2023
Sublease, area of property expected to be leased | ft²				10,500
Operating sublease, option to extend, description				The subtenants have no option to extend the sublease term.
Operating sublease, option to extend	false
Sublease income			$ 200,000	$ 300,000

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Commitments and Contingencies - Components of Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Commitments And Contingencies Disclosure [Abstract]
Total operating lease cost	$ 902	$ 603	$ 1,669	$ 1,196

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Commitments and Contingencies - Supplemental Cash Flow Information Related to Leases (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Commitments And Contingencies Disclosure [Abstract]
Operating cash flows from operating leases	$ 666	$ 3,133

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Commitments and Contingencies - Schedule by Year for Future Maturities of Operating Lease Liabilities and Sublease Income to be Received (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2021 USD ($)
Operating Leases
Operating Leases, 2021	$ 2,446
Operating Leases, 2022	4,994
Operating Leases, 2023	4,612
Operating Leases, 2024	4,772
Operating Leases, 2025	4,227
Operating Leases, Thereafter	19,709
Operating Leases, Total minimum lease payments	40,760
Less imputed interest	(15,277)
Operating lease liabilities	25,483
Sublease Income
Sublease Income, 2021	646
Sublease Income, 2022	1,048
Sublease Income, 2023	403
Total Sublease Income	2,097
Sublease Income, Total	$ 2,097

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Convertible Preferred Stock - Additional Information (Details)	1 Months Ended		3 Months Ended	6 Months Ended
	Jan. 31, 2021 USD ($) shares	Jun. 30, 2020 USD ($) Tranche $ / shares shares	Mar. 31, 2021 USD ($)	Jun. 30, 2021 USD ($) shares	Jun. 30, 2020 USD ($) $ / shares shares	Dec. 31, 2020 USD ($) shares
Class Of Stock [Line Items]
Convertible preferred stock value						$ 105,296,000
Convertible preferred stock, shares issued | shares				0		15,232,275
Proceeds from issuance of preferred stock, net of issuance cost				$ 51,902,000	$ 41,546,000
Series C-2 Convertible Preferred Stock
Class Of Stock [Line Items]
Fair value of convertible preferred stock purchase right liability	$ 31,300,000
Series C Agreement
Class Of Stock [Line Items]
Convertible preferred stock, authorized amount		$ 93,500,000			93,500,000
Number of tranches | Tranche		2
First Tranche Series C Agreement
Class Of Stock [Line Items]
Convertible preferred stock value		$ 41,300,000			$ 41,300,000
Net of issuance costs		$ 200,000
First Tranche Series C Agreement | Series C-1 Convertible Preferred Stock
Class Of Stock [Line Items]
Convertible preferred stock, shares issued | shares		5,162,173			5,162,173
Stock issued, price per share | $ / shares		$ 8.05			$ 8.05
First Tranche Series C Agreement | Series C-2 Convertible Preferred Stock
Class Of Stock [Line Items]
Convertible preferred stock, shares issuable | shares		5,611,065			5,611,065
Stock price per share | $ / shares		$ 9.2575			$ 9.2575
Potential gross proceeds from issuance		$ 51,900,000
Second Tranche Series C Agreement
Class Of Stock [Line Items]
Changes in fair value of this liability			$ 6,100,000
Second Tranche Series C Agreement | Series C-1 Convertible Preferred Stock
Class Of Stock [Line Items]
Fair value of convertible preferred stock purchase right liability		$ 13,500,000			$ 13,500,000
Second Tranche Series C Agreement | Series C-2 Convertible Preferred Stock
Class Of Stock [Line Items]
Convertible preferred stock, shares issued | shares	5,611,059
Proceeds from issuance of preferred stock, net of issuance cost	$ 51,900,000

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Common Stock - Additional Information (Details) - USD ($)	1 Months Ended
	Jul. 31, 2018	Feb. 28, 2021
Class Of Warrant Or Right [Line Items]
Warrants issued to purchase common stock	$ 249,218
Warrants expiration date	Jul. 26, 2028
Warrant exercise price	$ 0.07
Common Stock
Class Of Warrant Or Right [Line Items]
Number of common stock purchased upon exercise of warrants		82,603

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Stock-Based Compensation - Additional Information (Details) - USD ($)	1 Months Ended		3 Months Ended	6 Months Ended
	Jan. 31, 2021	Sep. 30, 2020	Jun. 30, 2021	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense				$ 4,132,000	$ 448,000
Performance and Service Based Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares granted		526,018
Vesting period		48 months
Stock-based compensation expense			$ 100,000	$ 600,000
Weighted-average grant date fair value of awards		$ 3.24
Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of common stock under employee stock purchase plan, Shares			29,685	29,685
2021 Plan | Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares authorized for issuance	8,075,000
2021 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Purchase price of stock as percentage of fair market value	85.00%
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			29,685	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	15.00%
2015 Plan | Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unvested shares			10,904	10,904		47,180
Repurchase right vesting period				4 years
Early exercise liability			$ 28,000	$ 28,000		$ 100,000

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Stock-Based Compensation - Summary of Components of Stock-Based Compensation Expense Recognized (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 2,023	$ 223	$ 4,132	$ 448
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	1,077	98	2,097	198
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 946	$ 125	$ 2,035	$ 250

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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		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Numerator:
Net loss	$ (23,585)	$ (11,059)	$ (48,039)	$ (19,692)
Denominator:
Weighted average common shares outstanding	36,617,390	1,937,510	29,104,021	1,935,575
Weighted average common stock outstanding subject to repurchase related to unvested early exercised stock options and restricted stock awards	(22,279)	(20,213)	(33,553)	(24,401)
Weighted average warrants to purchase common stock		172,023	17,798	172,023
Weighted average common shares outstanding - basic and diluted	36,595,112	2,089,320	29,088,267	2,083,197
Net loss per share attributable to common stockholders, basic and diluted	$ (0.64)	$ (5.29)	$ (1.65)	$ (9.45)

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Net Loss Per Share - Potentially Dilutive Securities not Included in the Calculation of Diluted Net Loss per Share (Details) - shares	3 Months Ended	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
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	5,102,618	17,241,208
Convertible Preferred Stock
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		15,232,275
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	5,091,714	1,992,801
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	10,904	16,132