0000950170-21-001573 | 10-Q | XBRL Viewer

Document and Entity Information - shares	6 Months Ended
Document and Entity Information - shares	Jun. 30, 2021	Aug. 15, 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	ERASCA, INC.
Entity Central Index Key	0001761918
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity File Number	001-40602
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	83-1217027
Entity Address, Address Line One	10835 Road to the Cure
Entity Address, Address Line Two	Suite 140
Entity Address, City or Town	San Diego
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92121
City Area Code	858
Local Phone Number	465-6511
Entity Current Reporting Status	Yes
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Entity Interactive Data Current	No
Entity Common Stock, Shares Outstanding		121,219,865
Document Quarterly Report	true
Document Transition Report	false
Title of 12(b) Security	Common Stock, $0.0001 par value per share
Trading Symbol	ERAS
Security Exchange Name	NASDAQ

Condensed Consolidated Balance Sheets (Unaudited) - USD ($)	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 156,396,000	$ 65,376,000
Short-term investments	37,277,000	53,325,000
Prepaid expenses and other current assets	3,618,000	1,289,000
Total current assets	197,291,000	119,990,000
Long-term investments	5,000,000
Property and equipment, net	2,257,000	1,847,000
Operating lease assets	1,877,000	2,225,000
Restricted cash	408,000	312,000
Other assets	3,550,000	451,000
Total assets	210,383,000	124,825,000
Current liabilities:
Accounts payable	1,507,000	878,000
Accrued expenses and other current liabilities	15,519,000	11,925,000
Operating lease liabilities	888,000	877,000
Total current liabilities	17,914,000	13,680,000
Operating lease liabilities, net of current portion	1,668,000	2,109,000
Preferred stock purchase right liability		1,615,000
Liabilities, Total	19,582,000	17,404,000
Commitments and contingencies (Note 12)
Stockholders' deficit:
Common stock, $0.0001 par value; 156,000,000 and 147,027,681 shares authorized as of June 30, 2021 and December 31, 2020, respectively, 27,300,123 and 25,189,673 shares issued at June 30, 2021 and December 31, 2020, respectively; 24,370,599 and 21,923,173 shares outstanding at June 30, 2021 and December 31, 2020, respectively	3,000	3,000
Additional paid-in capital	11,634,000	1,413,000
Accumulated other comprehensive income (loss)	(1,000)	2,000
Accumulated deficit	(161,633,000)	(115,402,000)
Total stockholders' deficit	(149,997,000)	(113,984,000)
Total liabilities, convertible preferred stock and stockholders' deficit	210,383,000	124,825,000
Convertible Preferred Stock
Current liabilities:
Convertible preferred stock (Series A, B-1 and B-2), $0.0001 par value; 97,622,409 shares authorized as of June 30, 2021 and December 31, 2020; 85,516,454 and 69,584,682 shares issued and outstanding as of June 30, 2021 and December 31, 2020, respectively; aggregate liquidation preference of $350,412 and $230,924 as of June 30, 2021 and December 31, 2020, respectively	$ 340,798,000	$ 221,405,000

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2021	Mar. 31, 2021	Feb. 28, 2021	Dec. 31, 2020	Jun. 30, 2020	Apr. 15, 2020	Mar. 31, 2020	Dec. 31, 2019
Convertible preferred stock, par value	$ 0.0001
Temporary equity, shares authorized	97,622,409
Common stock, par value	$ 0.0001			$ 0.0001		$ 0.0001
Common stock, shares authorized	156,000,000		156,000,000	147,027,681		147,027,681
Common stock, shares issued	27,300,123			25,189,673
Common stock, shares outstanding	24,370,599			21,923,173
Convertible Preferred Stock
Convertible preferred stock, par value	$ 0.0001			$ 0.0001
Temporary equity, shares authorized	97,622,409			97,622,409
Temporary equity, shares issued	85,516,454			69,584,682
Temporary equity, shares outstanding	85,516,454	85,516,454		69,584,682	63,184,682		38,103,681	38,103,681
Temporary equity, liquidation preference	$ 350,412			$ 230,924

Condensed Consolidated 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
Operating expenses:
Research and development	$ 17,598	$ 5,863	$ 29,843	$ 10,417
In-process research and development	5,488		9,168	17,670
General and administrative	5,098	1,421	8,780	3,032
Total operating expenses	28,184	7,284	47,791	31,119
Loss from operations	(28,184)	(7,284)	(47,791)	(31,119)
Other income (expense)
Interest income	31	70	61	255
Other expense	(61)	(33)	(116)	(41)
Change in fair value of preferred stock purchase right liability		1,756	1,615	1,756
Total other income (expense), net	(30)	1,793	1,560	1,970
Net loss	$ (28,214)	$ (5,491)	$ (46,231)	$ (29,149)
Net loss per share, basic and diluted	$ (1.20)	$ (0.26)	$ (2.02)	$ (1.41)
Weighted-average shares of common stock used in computing net loss per share, basic and diluted	23,546,390	20,834,976	22,893,533	20,733,283
Other comprehensive income (loss):
Unrealized gain (loss) on investments, net	$ (2)	$ 8	$ (3)	$ (14)
Comprehensive loss	$ (28,216)	$ (5,483)	$ (46,234)	$ (29,163)

Condensed Consolidated Statements of Convertible Preferred Stock and Stockholders' Deficit (Unaudited) - USD ($) $ in Thousands	Total	Convertible Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Convertible preferred stock, beginning balance, shares at Dec. 31, 2019		38,103,681
Convertible preferred stock, beginning balance, value at Dec. 31, 2019		$ 63,403
Beginning balance, shares at Dec. 31, 2019			22,629,158
Beginning balance at Dec. 31, 2019	$ (13,604)		$ 3	$ 124	$ 11	$ (13,742)
Exercise of stock options, shares			729,166
Stock-based compensation expense	105			105
Net loss	(23,658)					(23,658)
Unrealized gain (loss) on investments, net	(22)				(22)
Convertible preferred stock, ending balance, shares at Mar. 31, 2020		38,103,681
Convertible preferred stock,ending balance, value at Mar. 31, 2020		$ 63,403
Ending balance, shares at Mar. 31, 2020			23,358,324
Ending balance at Mar. 31, 2020	(37,179)		$ 3	229	(11)	(37,400)
Convertible preferred stock, beginning balance, shares at Dec. 31, 2019		38,103,681
Convertible preferred stock, beginning balance, value at Dec. 31, 2019		$ 63,403
Beginning balance, shares at Dec. 31, 2019			22,629,158
Beginning balance at Dec. 31, 2019	(13,604)		$ 3	124	11	(13,742)
Net loss	(29,149)
Convertible preferred stock, ending balance, shares at Jun. 30, 2020		63,184,682
Convertible preferred stock,ending balance, value at Jun. 30, 2020		$ 181,050
Ending balance, shares at Jun. 30, 2020			23,358,324
Ending balance at Jun. 30, 2020	(42,553)		$ 3	338	(3)	(42,891)
Convertible preferred stock, beginning balance, shares at Mar. 31, 2020		38,103,681
Convertible preferred stock, beginning balance, value at Mar. 31, 2020		$ 63,403
Beginning balance, shares at Mar. 31, 2020			23,358,324
Beginning balance at Mar. 31, 2020	(37,179)		$ 3	229	(11)	(37,400)
Issuance of Series B-1 and B-2 convertible preferred stock for cash, shares		25,081,001
Issuance of Series B-1 and B-2 convertible preferred stock for cash		$ 117,647
Stock-based compensation expense	109			109
Net loss	(5,491)					(5,491)
Unrealized gain (loss) on investments, net	8				8
Convertible preferred stock, ending balance, shares at Jun. 30, 2020		63,184,682
Convertible preferred stock,ending balance, value at Jun. 30, 2020		$ 181,050
Ending balance, shares at Jun. 30, 2020			23,358,324
Ending balance at Jun. 30, 2020	$ (42,553)		$ 3	338	(3)	(42,891)
Convertible preferred stock, beginning balance, shares at Dec. 31, 2020		69,584,682
Convertible preferred stock, beginning balance, value at Dec. 31, 2020		$ 221,405
Beginning balance, shares at Dec. 31, 2020	21,923,173		25,189,673
Beginning balance at Dec. 31, 2020	$ (113,984)		$ 3	1,413	2	(115,402)
Issuance of Series B-1 and B-2 convertible preferred stock for cash, shares		15,931,772
Issuance of Series B-1 and B-2 convertible preferred stock for cash		$ 119,393
Issuance of common stock in connection with asset acquisition, shares			500,000
Issuance of common stock in connection with asset acquisition	1,680			1,680
Exercise of stock options, shares			439,610
Exercise of stock options	94			94
Vesting of early exercised stock options	174			174
Stock-based compensation expense	795			795
Net loss	(18,017)					(18,017)
Unrealized gain (loss) on investments, net	(1)				(1)
Convertible preferred stock, ending balance, shares at Mar. 31, 2021		85,516,454
Convertible preferred stock,ending balance, value at Mar. 31, 2021		$ 340,798
Ending balance, shares at Mar. 31, 2021			26,129,283
Ending balance at Mar. 31, 2021	$ (129,259)		$ 3	4,156	1	(133,419)
Convertible preferred stock, beginning balance, shares at Dec. 31, 2020		69,584,682
Convertible preferred stock, beginning balance, value at Dec. 31, 2020		$ 221,405
Beginning balance, shares at Dec. 31, 2020	21,923,173		25,189,673
Beginning balance at Dec. 31, 2020	$ (113,984)		$ 3	1,413	2	(115,402)
Net loss	$ (46,231)
Convertible preferred stock, ending balance, shares at Jun. 30, 2021		85,516,454
Convertible preferred stock,ending balance, value at Jun. 30, 2021		$ 340,798
Ending balance, shares at Jun. 30, 2021	24,370,599		27,300,123
Ending balance at Jun. 30, 2021	$ (149,997)		$ 3	11,634	(1)	(161,633)
Convertible preferred stock, beginning balance, shares at Mar. 31, 2021		85,516,454
Convertible preferred stock, beginning balance, value at Mar. 31, 2021		$ 340,798
Beginning balance, shares at Mar. 31, 2021			26,129,283
Beginning balance at Mar. 31, 2021	(129,259)		$ 3	4,156	1	(133,419)
Issuance of common stock in connection with license agreement, shares			944,945
Issuance of common stock in connection with license agreement	5,488			5,488
Exercise of stock options, shares			225,895
Exercise of stock options	180			180
Vesting of early exercised stock options	174			174
Stock-based compensation expense	1,636			1,636
Net loss	(28,214)					(28,214)
Unrealized gain (loss) on investments, net	$ (2)				(2)
Convertible preferred stock, ending balance, shares at Jun. 30, 2021		85,516,454
Convertible preferred stock,ending balance, value at Jun. 30, 2021		$ 340,798
Ending balance, shares at Jun. 30, 2021	24,370,599		27,300,123
Ending balance at Jun. 30, 2021	$ (149,997)		$ 3	$ 11,634	$ (1)	$ (161,633)

Condensed Consolidated Statements of Convertible Preferred Stock and Stockholders' Deficit (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Jun. 30, 2020
Convertible Preferred Stock
Stock issuance costs	$ 95	$ 403
Preferred stock purchase right liability		$ 7,355

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Cash flows from operating activities:
Net loss			$ (46,231,000)	$ (29,149,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	$ 169,000	$ 134,000	318,000	255,000
Stock-based compensation expense			2,431,000	214,000
In-process research and development expenses	5,488,000		9,168,000	17,670,000
(Accretion) amortization on investments, net			46,000	(20,000)
Change in fair value of preferred stock purchase right liability		(1,756,000)	(1,615,000)	(1,756,000)
Changes in operating assets and liabilities:
Prepaid expenses and other current and long-term assets			(3,498,000)	(240,000)
Accounts payable			580,000	(521,000)
Accrued expenses and other current liabilities			4,984,000	1,458,000
Operating lease assets and liabilities, net			(82,000)	(26,000)
Net cash used in operating activities			(33,899,000)	(12,115,000)
Cash flows from investing activities:
Purchases of investments			(31,911,000)	(39,970,000)
Maturities of investments			42,910,000	19,792,000
In-process research and development			(6,000,000)	(17,670,000)
Purchases of property and equipment			(701,000)	(773,000)
Net cash provided by (used in) investing activities			4,298,000	(38,621,000)
Cash flows from financing activities:
Proceeds from the issuance of convertible preferred stock, net of issuance costs			119,393,000	125,002,000
Proceeds from the exercise of stock options, net of repurchases			1,324,000	490,000
Net cash provided by financing activities			120,717,000	125,492,000
Net increase in cash, cash equivalents and restricted cash			91,116,000	74,756,000
Cash, cash equivalents and restricted cash at beginning of the period			65,688,000	29,583,000	$ 29,583,000
Cash, cash equivalents and restricted cash at end of the period	$ 156,804,000	$ 104,339,000	156,804,000	104,339,000	$ 65,688,000
Supplemental disclosure of cash flow information:
Cash paid for taxes			72,000	51,000
Supplemental disclosure of noncash investing and financing activity:
Issuance of common stock in connection with asset acquisition			1,680,000
Issuance of common stock in connection with license agreement			5,488,000
Amounts accrued for purchases of property and equipment			101,000	4,000
Amounts accrued for deferred offering costs			1,930,000
Vesting of early exercised options			$ 348,000
Preferred stock purchase right liability				$ 7,355,000

Organization and Basis of Presentation

6 Months Ended

Jun. 30, 2021

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Organization and Basis of Presentation

Note 1. Organization and basis of presentation

Organization and nature of operations

Erasca, Inc. (Erasca or the Company) is a clinical-stage precision oncology company singularly focused on discovering, developing, and commercializing therapies for RAS/MAPK pathway-driven cancers. The Company has assembled a wholly-owned or controlled RAS/MAPK pathway-focused pipeline comprising 11 modality-agnostic programs aligned with its three therapeutic strategies of: (i) targeting key upstream and downstream signaling nodes in the RAS/MAPK pathway; (ii) targeting RAS directly; and (iii) targeting escape routes that emerge in response to treatment. The Company was incorporated under the laws of the State of Delaware on July 2, 2018, as Erasca, Inc., and is headquartered in San Diego, California. In September 2020, the Company established a wholly-owned Australian subsidiary, Erasca Australia Pty Ltd (Erasca Australia), in order to conduct clinical activities for its development candidates. In November 2020, the Company entered into an agreement and plan of merger with Asana BioSciences, LLC (Asana) and ASN Product Development, Inc. (the Asana Merger Agreement), pursuant to which Erasca—ASN Product Development, Inc. (ASN) became its wholly-owned subsidiary. In March 2021, the Company established a wholly-owned subsidiary, Erasca Ventures, LLC (Erasca Ventures), to potentially make equity investments in early-stage biotechnology companies that are aligned with the Company’s mission and strategy.

Since inception, the Company has devoted substantially all of its efforts and resources to organizing and staffing the Company, business planning, raising capital, identifying, acquiring and in-licensing the Company’s product candidates, establishing its intellectual property portfolio, conducting research, preclinical studies, and clinical trials, establishing arrangements with third parties for the manufacture of its product candidates and related raw materials, and providing general and administrative support for these operations. As of June 30, 2021, the Company had $193.7 million in cash, cash equivalents, and short-term investments, respectively. As of June 30, 2021, the Company had an accumulated deficit of $161.6 million. The Company has incurred significant operating losses and negative cash flows from operations. From its inception through June 30, 2021, the Company’s financial support has primarily been provided from the sale of its convertible preferred stock.

As the Company continues its expansion, it expects to use its cash, cash equivalents, and short-term investments to fund research and development, working capital, and other general corporate purposes. The Company does not expect to generate any revenues from product sales unless and until the Company successfully completes development and obtains regulatory approval for any of its product candidates, which will not be for at least the next several years, if ever. Accordingly, until such time as the Company can generate significant revenue from sales of its product candidates, if ever, the Company expects to finance its cash needs through equity offerings, debt financings, or other capital sources, including potential collaborations, licenses or other similar arrangements. However, the Company may not be able to secure additional financing or enter into such other arrangements in a timely manner or on favorable terms, if at all. The Company’s failure to raise capital or enter into such other arrangements when needed would have a negative impact on the Company’s financial condition and could force the Company to delay, limit, reduce or terminate its research and development programs or other operations, or grant rights to develop and market product candidates that the Company would otherwise prefer to develop and market itself. The Company believes its cash, cash equivalents, and short-term investments as of June 30, 2021 and the net proceeds of $317.7 million received from the Company’s initial public offering (IPO), which closed on July 20, 2021, will be sufficient for the Company to fund operations for at least one year from the issuance date of these condensed consolidated financial statements.

Initial public offering

On July 20, 2021, the Company completed its initial public offering (IPO) in which the Company issued and sold 21,562,500 shares of common stock (including 2,812,500 shares of common stock in connection with the full exercise of the underwriters’ option to purchase additional shares) at an offering price of $16.00 per share. Proceeds from the IPO, net of underwriting discounts, commissions and estimated offering costs, were $317.7 million. In connection with the completion of the IPO, all outstanding shares of convertible preferred stock were converted into 71,263,685 shares of common stock.

Basis of presentation

The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with US generally accepted accounting principles (US GAAP). Any reference in these notes to applicable guidance is meant to refer to US GAAP as found in the Accounting Standards Codification (ASC) and Accounting Standards Updates (ASU) promulgated by the Financial Accounting Standards Board (FASB).

Principles of consolidation and foreign currency transactions

The Company’s consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries, Erasca Australia, ASN and Erasca Ventures. Erasca Australia was registered under the laws of Australia on September 1, 2020, ASN was incorporated under the laws of the State of Delaware on November 23, 2020 and Erasca Ventures was formed under the laws of the State of Delaware on March 30, 2021. All intercompany balances and transactions have been eliminated. The functional currency of the Company and its wholly-owned subsidiaries is the US dollar. Assets and liabilities that are not denominated in the functional currency are remeasured into US dollars at foreign currency exchange rates in effect at the balance sheet date except for nonmonetary assets, which are remeasured at historical foreign currency exchange rates in effect at the date of transaction. Net realized and unrealized gains and losses from foreign currency transactions and remeasurement are reported in other income (expense), in the consolidated statements of operations and comprehensive loss and were not material for all periods presented.

Summary of Significant Accounting Policies

6 Months Ended

Jun. 30, 2021

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

Note 2. Summary of significant accounting policies

Use of estimates

The preparation of the Company’s consolidated financial statements in conformity with US GAAP requires the Company to make estimates and assumptions that impact the reported amounts of assets, liabilities, expenses, and the disclosure of contingent assets and liabilities in the consolidated financial statements and accompanying notes. Accounting estimates and management judgments reflected in the consolidated financial statements include, but are not limited to, the accrual of research and development expenses, fair value of common stock, preferred stock and freestanding instruments, stock-based compensation expense, and the incremental borrowing rate for determining the operating lease asset and liability. Management evaluates its estimates on an ongoing basis. Although estimates are based on the Company’s historical experience, knowledge of current events, and actions it may undertake in the future, actual results may ultimately materially differ from these estimates and assumptions.

Unaudited interim financial information

The accompanying condensed consolidated balance sheet as of June 30, 2021, the condensed consolidated statements of operations and comprehensive loss for the three and six months ended June 30, 2021 and 2020, the condensed consolidated statements of convertible preferred stock and stockholders’ deficit for the three and six months ended June 30, 2021 and 2020 and the condensed consolidated statements of cash flows for the six months ended June 30, 2021 and 2020 are unaudited. The unaudited condensed consolidated interim financial statements have been prepared on the same basis as the audited annual consolidated financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair statement of the Company’s condensed consolidated financial position as of June 30, 2021 and the condensed consolidated results of its operations and cash flows for the three and six months ended June 30, 2021 and 2020. The condensed consolidated financial data and other information disclosed in these notes related to the three and six months ended June 30, 2021 and 2020 are unaudited. The condensed consolidated results for the three and six months ended

June 30, 2021 are not necessarily indicative of results to be expected for the year ending December 31, 2021, any other interim periods, or any future year or period.

Concentration of credit risk and off-balance sheet risk

Financial instruments which potentially subject the Company to significant concentration of credit risk consist of cash and cash equivalents and investments. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. The Company has not experienced any losses in such accounts, and management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held. The Company’s investment policy includes guidelines for the quality of the related institutions and financial instruments and defines allowable investments that the Company may invest in, which the Company believes minimizes the exposure to concentration of credit risk.

Cash, cash equivalents and restricted cash

Cash and cash equivalents include cash in readily available checking and savings accounts, money market funds, commercial paper, and corporate debt securities. The Company considers all highly liquid investments with an original maturity of three months or less from the date of purchase to be cash equivalents.

The Company had deposited cash of $408,000 and $312,000 as of June 30, 2021 and December 31, 2020, respectively, to secure a letter of credit in connection with the lease of the Company’s facilities (see Note 11). The Company has classified the restricted cash as a noncurrent asset on its condensed consolidated balance sheets.

The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the condensed consolidated balance sheets that sum to the total of the same amounts shown in the condensed consolidated statements of cash flows (in thousands):


	June 30,
	2021		2020
Cash and cash equivalents	$	156,396	$	104,339
Restricted cash		408		—
Total cash, cash equivalents and restricted cash as shown on the condensed consolidated statements of cash flows	$	156,804	$	104,339

Investments

The Company classifies all marketable securities as available-for-sale, as the sale of such securities may be required prior to maturity. Management determines the appropriate classification of its investments in debt securities at the time of purchase. Investments with original maturities beyond three months at the date of purchase and which mature at, or less than 12 months from, the balance sheet date are classified as short-term investments. Available-for-sale securities are carried at fair value, with the unrealized gains and losses reported as accumulated other comprehensive income (loss) until realized. The amortized cost of available-for-sale debt securities is adjusted for amortization of premiums and accretion of discounts to maturity. Such amortization and accretion are included in interest income. The Company regularly reviews all its investments 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 securities in an unrealized loss position, the severity and duration of the unrealized losses, whether the Company has the intent to sell the securities and whether it is more likely than not that the Company will be required to sell the securities before the recovery of their amortized cost basis. When the Company determines that the decline in fair value of an investment is below its accounting basis and the decline is other-than-temporary, the Company reduces the carrying value of the security it holds and records a loss for the amount of such decline. Realized gains and losses and declines in value judged to be other than temporary, if any, on available-for-sale securities are included in other income or expense. The cost of securities sold is based on the specific identification method. Interest and dividends on securities classified as available-for-sale are included in interest income.

Fair value measurements

Certain assets and liabilities are carried at fair value under US GAAP. Fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. 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. Financial assets and liabilities carried at fair value are classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable:

Level 1—Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities.

Level 2—Quoted prices for similar assets and liabilities in active markets, quoted prices in markets that are not active, or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liability.

Level 3—Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity).

Property and equipment, net

Property and equipment are stated at cost less accumulated depreciation. Depreciation and amortization are calculated using the straight-line method over the estimated useful lives of the respective assets, generally three to seven years. Leasehold improvements are amortized over the shorter of the estimated useful lives of the assets or the remaining lease term.

Impairment of long-lived assets

The Company continually evaluates long-lived assets for potential impairment when events or changes in circumstances indicate the carrying value of the assets may not be recoverable. Recoverability is measured by comparing the book values of the assets to the expected future net undiscounted cash flows that the assets are expected to generate. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the book values of the assets exceed their fair value. The Company did not recognize any impairment losses for the three and six months ended June 30, 2021 and 2020.

Leases

The Company leases real estate facilities and equipment under non-cancelable and cancelable operating leases with various expiration dates through fiscal year 2032. At the inception of an arrangement, the Company determines whether the arrangement is or contains a lease based on the unique facts and circumstances present, the existence of an identified asset(s), if any, and the Company’s control over the use of the identified asset(s), if applicable.

Operating leases are included in operating lease assets and in operating lease liabilities in the accompanying condensed consolidated balance sheets. Operating lease assets represent the Company’s right to use an underlying asset for the lease term, and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. Operating lease liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term discounted based on the more readily determinable of (i) the rate implicit in the lease or (ii) the Company’s incremental borrowing rate (which is the estimated rate the Company would be required to pay for a collateralized borrowing equal to the total lease payments over the term of the lease). Because the Company’s operating leases generally do not provide an implicit rate, the Company estimates its incremental borrowing rate based on the information available at lease commencement date for borrowings with a similar term.

The Company’s operating lease assets are measured based on the corresponding operating lease liability adjusted for (i) payments made to the lessor at or before the commencement date, (ii) initial direct costs incurred and (iii) tenant incentives under the lease. The Company does not assume renewals or early terminations unless it is reasonably certain to exercise these options at commencement. The Company elected the practical expedient which allows the Company to not allocate consideration between lease and non-lease components. Variable lease payments are recognized in the period in which the obligations for those payments are incurred. In addition, the Company elected the practical expedient such that it does not recognize lease assets or lease liabilities for leases with a term of 12 months or less of all asset classes. Operating lease expense is recognized on a straight-line basis over the lease term.

Research and development expense

Research and development expenses consist of external and internal costs associated with the Company’s research and development activities, including its discovery and research efforts and the preclinical and clinical development of its product candidates. Research and development costs are expensed as incurred. The Company’s research and development expenses include external costs, consisting of expenses incurred under arrangements with third parties, such as contract research organizations, contract manufacturers, consultants and its scientific advisors; and internal costs, consisting of employee-related expenses, including salaries, benefits, and stock-based compensation for those individuals involved in research and development efforts, the costs of laboratory supplies and acquiring, developing and manufacturing preclinical study materials, and facilities and depreciation, which include direct and allocated expenses for rent of facilities and depreciation of equipment.

The Company records accruals for estimated research and development costs, comprising payments for work performed by third party contractors, laboratories, and others. Some of these contractors bill monthly based on actual services performed, while others bill periodically based upon achieving certain contractual milestones. For the latter, the Company accrues the expenses as goods or services are used or rendered. Non-refundable advance payments for goods or services that will be used or rendered for future research and development activities are deferred and capitalized as prepaid expenses until the related goods are delivered or services are performed.

In-process research and development expense

The Company has acquired rights as part of asset acquisitions or in-licenses to develop and commercialize product candidates. Upfront payments that relate to the acquisition of a new drug compound, as well as pre-commercial milestone payments, are immediately expensed as in-process research and development (IPR&D) in the period in which they are incurred, provided that the new drug compound did not also include processes or activities that would constitute a “business” as defined under US GAAP, the drug has not achieved regulatory approval for marketing and, absent obtaining such approval, has no established alternative future use. The Company accounts for contingent consideration payable upon achievement of certain regulatory, development or sales milestones in such asset acquisitions when the underlying contingency is resolved. Milestone payments made to third parties subsequent to regulatory approval will be capitalized as intangible assets and amortized over the estimated remaining useful life of the related product.

Patent costs

The Company expenses all costs as incurred in connection with patent applications (including direct application fees, and the legal and consulting expenses related to making such applications) and such costs are included in general and administrative expenses in the consolidated statements of operations and comprehensive loss.

Deferred offering costs

The Company capitalizes certain legal, professional accounting and other third-party fees that are directly associated with in-process equity financings as deferred offering costs until such financings are consummated. After consummation of the equity financing, these costs are recorded in stockholders’ deficit as a reduction of proceeds generated as a result of the offering. Should the in-process equity financing be abandoned, the deferred offering costs will be expensed immediately as a charge to operating expenses in the consolidated statements of operations and comprehensive loss. As of June 30, 2021, $2.6 million of

deferred offering costs were recorded in other assets on the Company’s condensed consolidated balance sheet. There were no deferred offering costs as of December 31, 2020.

Common stock valuation

Due to the absence of an active market for the Company’s common stock prior to the IPO, the Company utilized methodologies, approaches and assumptions consistent with the American Institute of Certified Public Accountants’ Audit and Accounting Practice Guide: Valuation of Privately-Held Company Equity Securities Issued as Compensation to estimate the fair value of its common stock. In determining the exercise prices for options granted, the Company has considered the fair value of the common stock as of the grant date. The fair value of the common stock has been determined based upon a variety of factors, including valuations of the Company’s common stock performed with the assistance of independent third-party valuation specialists; the Company’s stage of development and business strategy, including the status of research and development efforts of its product candidates, and the material risks related to its business and industry; the Company’s business conditions and projections; the Company’s results of operations and financial position, including its levels of available capital resources; the valuation of publicly traded companies in the life sciences and biotechnology sectors, as well as recently completed mergers and acquisitions of peer companies; the lack of marketability of the Company’s common stock as a private company; the prices of the Company’s convertible preferred stock sold to investors in arm’s length transactions and the rights, preferences and privileges of its convertible preferred stock relative to those of its common stock; the likelihood of achieving a liquidity event for the holders of the Company’s common stock, such as an initial public offering or a sale of the Company given prevailing market conditions; trends and developments in its industry; the hiring of key personnel and the experience of management; and external market conditions affecting the life sciences and biotechnology industry sectors. Significant changes to the key assumptions underlying the factors used could result in different fair values of common stock at each valuation date.

Stock-based compensation

The Company measures employee and nonemployee stock-based awards based on the fair value on the date of grant and records compensation expense on a straight-line basis over the requisite service period of the award. The Company records the expense for stock-based compensation awards subject to performance-based milestone vesting over the implied service period when management determines that achievement of the milestone is probable. Management evaluates when the achievement of a performance-based milestone is probable based on the expected satisfaction of the performance conditions at each reporting date. All stock-based compensation costs are recorded in the consolidated statements of operations and comprehensive loss based upon the underlying employees or nonemployee’s roles within the Company. Forfeitures are accounted for as they occur.

The fair value of each stock option grant is estimated on the date of grant using the Black-Scholes options-pricing model, which requires inputs based on certain subjective assumptions, including the:

• Fair value of common stock. As there was no active market for the Company’s common stock prior to the IPO, the Company estimated the fair value of common stock on the date of grant based on the then current facts and circumstances.

• Risk-free interest rate. The risk-free interest rate is based on the US Treasury zero-coupon issues in effect at the time of grant for periods corresponding with the expected term of the options.

• Expected volatility. Given that the Company’s common stock was privately held prior to the IPO, there was no active trading market for its common stock. The Company derived the expected volatility from the average historical volatilities over a period approximately equal to the expected term of comparable publicly traded companies within its peer group that were deemed to be representative of future stock price trends. The Company will continue to apply this process until a sufficient amount of historical information regarding the volatility of its own stock price becomes available.

• Expected term. The expected term represents the period that the options granted are expected to be outstanding. The expected term of stock options issued is determined using the simplified method (based on the mid-point between the vesting date and the end of the contractual term) as the Company has concluded that its stock option exercise history does not provide a reasonable basis upon which to estimate expected term.

• Expected dividend yield. The Company has never paid dividends on its common stock and does not anticipate paying any dividends in the foreseeable future. Therefore, the Company used an expected dividend yield of zero.

The fair value of each restricted common stock award is estimated on the date of grant based on the fair value of the Company’s common stock on that same date.

Classification and accretion of convertible preferred stock

The Company’s convertible preferred stock is classified outside of stockholders’ deficit on the consolidated balance sheets because the holders of such shares have liquidation rights in the event of a deemed liquidation that, in certain situations, are not solely within the control of the Company and would require the redemption of the then-outstanding convertible preferred stock. The convertible preferred stock is not redeemable, except in the event of a deemed liquidation. Because the occurrence of a deemed liquidation event is not currently probable, the carrying values of the convertible preferred stock are not being accreted to their redemption values. Subsequent adjustments to the carrying values of the convertible preferred stock would be made only when a deemed liquidation event becomes probable.

Preferred stock purchase right liabilities

The Company has entered into convertible preferred stock financings where, in addition to the initial closing, investors agree to buy, and the Company agrees to sell, additional shares of that convertible preferred stock at a fixed price in the event that certain conditions are met or agreed upon milestones are achieved. The Company evaluates this purchase right and assesses whether it meets the definition of a freestanding instrument and, if so, determines the fair value of the purchase right liability and records it on the balance sheet with the remainder of the proceeds raised allocated to convertible preferred stock. The preferred stock purchase right liability is revalued at each reporting period with changes in the fair value of the liability recorded as change in fair value of preferred stock purchase right liability in the consolidated statements of operations and comprehensive loss. The preferred stock purchase right liability is revalued at settlement and the resultant fair value, if any, is then reclassified to convertible preferred stock at that time.

Income taxes

The Company recognizes deferred tax assets and liabilities for the expected future tax consequences of events that have been recognized in the Company’s consolidated financial statements or tax returns. Under this method, deferred tax assets and liabilities are determined based on differences between the financial statement carrying amounts and the tax bases of the assets and liabilities using the enacted tax rates in effect in the years in which the differences are expected to reverse. A valuation allowance against deferred tax assets is recorded if, based on the weight of the available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized.

The Company accounts for uncertainty in income taxes recognized in the consolidated financial statements by applying a two-step process to determine the amount of tax benefit to be recognized. First, the tax position must be evaluated to determine the likelihood that it will be sustained upon external examination by the taxing authorities. If the tax position is deemed more-likely-than-not to be sustained, the tax position is then assessed to determine the amount of benefit to recognize in the consolidated financial statements. The amount of the benefit that may be recognized is the largest amount that has a greater than 50% likelihood of being realized upon ultimate settlement. The provision for income taxes includes the effects of any resulting tax reserves, or unrecognized tax benefits, that are considered appropriate as well as the related net interest and penalties. As of June 30, 2021, the Company’s tax years since inception are subject to examination by taxing authorities due to the Company’s unutilized net operating losses and tax credits.

Comprehensive income (loss)

The Company reports all components of comprehensive income (loss), including net loss, in the consolidated financial statements in the period in which they are recognized. Comprehensive income (loss) is defined as the change in equity during a period from transactions and other events and circumstances from non-owner sources, including unrealized gains and losses on

investments. Other comprehensive income includes unrealized gains and losses on investments, which was the only difference between net loss and comprehensive loss for the applicable periods.

Net loss per share

The Company’s net loss is equivalent to net loss attributable to common stockholders for all periods presented. Basic net loss per share is calculated by dividing the net loss by the weighted-average number of common shares outstanding during the period, without consideration of potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss by the weighted-average number of common shares and potentially dilutive securities outstanding for the period. For purposes of the diluted net loss per share calculation, the convertible preferred stock, options to purchase common stock and common stock subject to repurchase related to unvested restricted stock and options early exercised 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 Company’s participating securities do not have a contractual obligation to share in the Company’s losses. As such, the net loss was attributed entirely to common stockholders. As the Company has reported a net loss for all periods presented, diluted net loss per common share is the same as basic net loss per common share for those periods, since dilutive common shares are not assumed to have been issued if their effect is anti-dilutive.

Segments

The Company has determined that its chief executive officer is the chief operating decision maker (CODM). The Company operates and manages the business as one reporting and one operating segment, which is the business of discovering and developing precision medicines for the benefit of patients with cancer. The Company’s CODM reviews financial information on an aggregate basis for purposes of allocating resources and evaluating financial performance. All of the Company’s assets are located in the United States.

Recently adopted accounting pronouncements

In August 2018, the FASB issued ASU 2018-13, Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement. The primary focus of the standard is to improve the effectiveness of the disclosure requirements for fair value measurements. The Company adopted this guidance on January 1, 2020, with no material impact on its consolidated financial statements or related disclosures.

In August 2018, the FASB issued ASU 2018-15, Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract (ASU 2018-15). The new standard will align the requirements for capitalizing implementation costs for hosting arrangements (services) with costs for internal-use software (assets). As a result, certain implementation costs incurred in hosting arrangements will be deferred and amortized. The Company adopted ASU 2018-15 on January 1, 2021, and the adoption had an immaterial impact on its consolidated financial statements and related disclosures.

Recently issued accounting pronouncements not yet adopted

From time to time, new accounting pronouncements are issued by the FASB or other standard setting bodies that the Company adopts as of the specified effective date. The Company qualifies as an “emerging growth company” as defined in the Jumpstart Our Business Startups Act of 2012 and has elected not to “opt out” of the extended transition related to complying with new or revised accounting standards, which means that when a standard is issued or revised and it has different application dates for public and nonpublic companies, the Company can adopt the new or revised standard at the time nonpublic companies adopt the new or revised standard and can do so until such time that the Company either (i) irrevocably elects to “opt out” of such extended transition period or (ii) no longer qualifies as an emerging growth company.

In June 2016, the FASB issued ASU 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (ASU 2016-13) and also issued subsequent amendments to the initial guidance: ASU 2018-19, ASU 2019-04, ASU 2019-05, and ASU 2019-11. The standard requires that credit losses be reported using an expected losses model rather than the incurred losses model that is currently used, and it establishes additional disclosure requirements related to credit risks. For available-for-sale debt securities with expected credit losses, this standard now requires allowances to be recorded instead of reducing the amortized cost of the investment. This guidance was originally effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years, and early adoption was permitted. In November 2019, the FASB subsequently issued ASU 2019-10, Financial Instruments—Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842): Effective Dates, whereby the effective date of this standard for smaller reporting companies was deferred to fiscal years beginning after December 15, 2022, including interim periods within those fiscal years, and early adoption is still permitted. The Company is currently evaluating the potential impact ASU 2016-13, and related updates, will have on its consolidated financial statements and related disclosures upon adoption.

In August 2020, the FASB issued ASU 2020-06, Debt: Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40) (ASU 2020-06), which simplifies the accounting for convertible instruments and contracts in an entity’s own equity. This guidance is effective for the Company in its annual reporting period beginning after December 15, 2023, including interim periods within that reporting period, with early adoption permitted only as of annual reporting periods beginning after December 15, 2020. The Company is currently assessing the impact this standard will have on its consolidated financial statements and related disclosures upon adoption.

Fair Value Measurements

6 Months Ended

Jun. 30, 2021

Fair Value Disclosures [Abstract]

Fair value measurements

Note 3. Fair value measurements

The following tables summarize the Company’s financial assets and liabilities measured at fair value on a recurring basis and their respective input levels based on the fair value hierarchy (in thousands):


			Fair value measurements as of June 30, 2021 using
			Quoted prices in		Significant		Significant
			active markets		other		unobservable
			for identical		observable		inputs
	June 30, 2021		assets (level 1)		inputs (level 2)		(level 3)
Assets:
Money market funds(1)	$	150,184	$	150,184	$	—	$	—
US treasury securities(2)		5,000		5,000		—		—
US government securities(2)		5,053		—		5,053		—
Corporate debt securities(2)		3,328		—		3,328		—
Commercial paper(2)		22,380		—		22,380		—
Supranational debt securities(2)		1,516		—		1,516		—
US government securities(3)		5,000		—		5,000		—
Total fair value of assets	$	192,461	$	155,184	$	37,277	$	—

(1)

Included as cash and cash equivalents on the condensed consolidated balance sheets.

(2)

Included as short-term investments on the condensed consolidated balance sheets.

(3)

Included as long-term investments on the condensed consolidated balance sheets.

As of June 30, 2021, there were no financial liabilities measured at fair value on a recurring basis.


			Fair value measurements as of December 31, 2020 using
			Quoted prices in		Significant		Significant
			active markets		other		unobservable
	December 31,		for identical		observable		inputs
	2020		assets (level 1)		inputs (level 2)		(level 3)
Assets:
Money market funds(1)	$	57,238	$	57,238	$	—	$	—
Commercial paper(1)		900		—		900		—
US treasury securities(2)		38,492		38,492		—		—
Corporate debt securities(2)		3,793		—		3,793		—
Commercial paper(2)		11,040		—		11,040		—
Total fair value of assets	$	111,463	$	95,730	$	15,733	$	—
Liabilities:
Preferred stock purchase right liability		1,615		—		—		1,615
Total fair value of liabilities	$	1,615	$	—	$	—	$	1,615

(1)

Included as cash and cash equivalents on the consolidated balance sheets.

(2)

Included as short-term investments on the consolidated balance sheets.

The carrying amounts of the Company’s financial instruments, including cash, prepaid and other current assets, accounts payable, and accrued expenses and other current liabilities, approximate fair value due to their short maturities. None of the Company’s non-financial assets or liabilities are recorded at fair value on a non-recurring basis. No transfers between levels have occurred during the periods presented. There are uncertainties on the fair value measurement of the instrument classified under Level 3 due to the use of unobservable inputs and interrelationships between these unobservable inputs, which could result in higher or lower fair value measurements.

Cash equivalents consist of money market funds, commercial paper and corporate debt securities, short-term investments consist of US treasury and government securities, corporate debt securities, commercial paper and supranational debt securities, and long-term investments consist of US government securities. 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, and bid and/or offers.

Preferred stock purchase right liability

As of December 31, 2020, the quantitative elements associated with the Company’s Level 3 inputs impacting the fair value measurement of the preferred stock purchase right liability include the fair value per share of the underlying Series B-1 Preferred Stock, the expected term of the purchase right liability, risk-free interest rate, expected dividend yield and expected volatility of the price of the underlying preferred stock. The most significant assumption in the Black-Scholes option-pricing model impacting the fair value of the preferred stock purchase right liability was the fair value of the Company’s convertible preferred stock as of each measurement date. The Company determined the fair value per share of the underlying preferred stock by taking into consideration its most recent sales of its convertible preferred stock as well as additional factors that the Company deemed relevant. The Company lacks company-specific historical and implied volatility information of its stock. Therefore, it estimated its expected preferred stock volatility based on the historical volatility of publicly traded peer companies for a term equal to the expected term of the purchase right liability. The risk-free interest rate was determined by reference to the US Treasury yield curve for time periods approximately equal to the expected term of the purchase right liability. The Company estimated a 0% dividend yield based on the expected dividend yield and the fact that the Company never paid or declared dividends. The change in fair value of the purchase right liability was a gain of $1.8 million for the three and six months ended June 30, 2020, included in other income (expense) within the condensed consolidated statements of operations and comprehensive loss. Upon the issuance of the shares of the Company’s Series B-2 convertible preferred stock in January 2021, the purchase right liability was revalued with the gain of $1.6 million recorded in change in fair value of the purchase right liability for the six months ended June 30, 2021 within the condensed consolidated statements of operations and comprehensive loss. Significant changes in the assumptions could have a material impact on the value of the preferred stock purchase right liability. The assumptions used in the

Black-Scholes option pricing model to determine the fair value of the preferred stock purchase right liability at settlement date and December 31, 2020 were as follows:


	Settlement Date			December 31, 2020
Fair value of underlying preferred stock	$	6.11		$	6.11
Risk-free interest rate		0.07	%		0.08	%
Expected volatility		74.4	%		71.8	%
Expected term (in years)		0.00			0.08
Expected dividend yield		—	%		—	%

- Definition

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

+ References + Details

Investments

6 Months Ended

Jun. 30, 2021

Investments Debt And Equity Securities [Abstract]

Investments

Note 4. Investments

The following tables summarize the Company’s investments accounted for as available-for-sale securities (in thousands, except years):


	June 30, 2021
	Maturity	Amortized		Unrealized			Unrealized		Estimated
	(in years)	cost		losses			gains		fair value
US treasury securities	1 or less	$	5,000	$	—		$	—	$	5,000
US government securities	1 or less		5,053		—			—		5,053
Corporate debt securities	1 or less		3,328		—			—		3,328
Commercial paper	1 or less		22,380		—			—		22,380
Supranational debt securities	1 or less		1,516		—			—		1,516
US government securities	1-2		5,001		(1	)		—		5,000
Total		$	42,278	$	(1	)	$	—	$	42,277


	December 31, 2020
	Maturity	Amortized		Unrealized			Unrealized		Estimated
	(in years)	cost		losses			gains		fair value
US treasury securities	1 or less	$	38,489	$	—		$	3	$	38,492
Corporate debt securities	1 or less		3,794		(1	)		—		3,793
Commercial paper	1 or less		11,040		—			—		11,040
Total		$	53,323	$	(1	)	$	3	$	53,325

As of June 30, 2021, there were two available-for-sale securities with an estimated fair value of $6.5 million in gross unrealized loss positions. None had been in such position for greater than 12 months. As of December 31, 2020, there were six available-for-sale securities with an estimated fair value of $15.8 million in gross unrealized loss positions. Based on the Company’s review of its investments, the Company believes that the unrealized losses were not other-than-temporary as of June 30, 2021 and December 31, 2020.

Property and Equipment, Net

6 Months Ended

Jun. 30, 2021

Property Plant And Equipment [Abstract]

Property and Equipment, Net

Note 5. Property and equipment, net

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


	June 30,			December 31,
	2021			2020
Leasehold improvements	$	795		$	795
Laboratory equipment		2,083			1,380
Furniture and fixtures		168			165
Office equipment		61			61
Software		70			70
Computer equipment		299			278
Property and equipment		3,476			2,749
Less accumulated depreciation and amortization		(1,219	)		(902	)
Property and equipment, net	$	2,257		$	1,847

Depreciation and amortization expense related to property and equipment was $169,000 and $318,000 for the three and six months ended June 30, 2021, respectively, and $134,000 and $255,000 for the three and six months ended June 30, 2020,

Accrued expenses and other current liabilities

6 Months Ended

Jun. 30, 2021

Payables And Accruals [Abstract]

Accrued Expenses and Other Current Liabilities

Note 6. Accrued expenses and other current liabilities

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


	June 30,		December 31,
	2021		2020
Accrued research and development expenses	$	6,307	$	6,649
Accrued compensation		3,069		2,416
Unvested early exercised stock option liability		3,230		2,526
Accrued offering costs		1,870	—
Accrued legal		468		194
Other accruals		575		140
Total	$	15,519	$	11,925

Asset Acquisitions

6 Months Ended

Jun. 30, 2021

Asset Acquisitions [Abstract]

Asset Acquisitions

Note 7. Asset acquisitions

The following purchased assets were accounted for as asset acquisitions as substantially all of the fair value of the assets acquired were concentrated in a group of similar assets, and the acquired assets did not have outputs or employees. Because the assets had not yet received regulatory approval, the fair value attributable to these assets was recorded as in-process research and development expenses in the Company’s consolidated statements of operations and comprehensive loss.

Asana BioSciences, LLC

In November 2020, the Company entered into the Asana Merger Agreement, pursuant to which ASN became its wholly-owned subsidiary. Asana and ASN had previously entered into a license agreement, which was amended and restated prior to the closing of the merger transaction (the Asana License Agreement, and collectively with the Asana Merger Agreement, the Asana Agreements), pursuant to which ASN acquired an exclusive, worldwide license to certain intellectual property rights relating to inhibitors of ERK1 and ERK2 owned or controlled by Asana to develop and commercialize ERAS-007 and certain other related compounds for all applications. The Company has the right to sublicense (through multiple tiers) the licensed rights under the Asana Agreements, subject to certain conditions. The foregoing license is subject to Asana’s non-exclusive right to practice the licensed rights to research and conduct preclinical pharmacology activities with a specified combination of compounds, subject to certain specified conditions. Pursuant to the Asana License Agreement, neither Asana nor ASN can directly or indirectly exploit certain classes of competing products, subject to specified exceptions. In addition, the Company is required to use commercially reasonable efforts to develop and obtain regulatory approval for ERAS-007 in the United States, at least one major market country in Europe, and either China or Japan.

Under the Asana Merger Agreement, the Company made an upfront payment of $20.0 million and issued 4,000,000 shares of its Series B-2 convertible preferred stock to Asana at a value of $7.50 per share or a total fair value of $30.0 million. The Company is obligated to make future development and regulatory milestone cash payments for a licensed product in an amount of up to $90.0 million. Additionally, upon achieving a development milestone related to demonstration of successful proof-of-concept in a specified clinical trial, the Company will also be required to issue 3,888,889 shares of its common stock to Asana. The Company is not obligated to pay royalties on the net sales of licensed products. The Company recorded IPR&D expense of $50.0 million during the year ended December 31, 2020 in connection with the asset acquisition. No IPR&D expense was recorded during the three and six months ended June 30, 2021 and 2020. As of June 30, 2021 and December 31, 2020, no milestones had been accrued as the underlying contingencies had not yet been resolved.

Upon the Company’s payment to Asana of all merger consideration, including upfront cash and equity payments, the equity payment related to the proof-of-concept development milestone, and all other development milestone payments, with the exception of a specific milestone that does not need to be achieved at such time and will remain subject to payment in the event that such milestone is achieved at a later time, all licensed rights will become fully paid-up, perpetual, and irrevocable. The Asana License Agreement may be terminated by either Asana or the Company in the event of an uncured material breach by the other party. Asana also has the right to terminate the Asana License Agreement if the Company fails to engage in material activities in support of clinical development and commercialization of ERAS-007 for a period of 12 consecutive months, excluding reasons outside of its reasonable control and subject to certain limitations. However, Asana’s right to terminate the Asana License Agreement for any reason ends once the Company has paid to Asana all merger consideration, or if Asana’s equity interest in the Company becomes publicly traded and exceeds a certain threshold value. The Company may terminate the Asana License Agreement at any time upon the provision of prior written notice to Asana.

Emerge Life Sciences, Pte. Ltd.

In March 2021, the Company entered into an asset purchase agreement (ELS Purchase Agreement) with Emerge Life Sciences, Pte. Ltd. (ELS) wherein it purchased all rights, title, and interest (including all patent and other intellectual property rights) to EGFR antibodies directed against the EGFR domain II (EGFR-D2) and domain III (EGFR-D3) as well as a bispecific antibody where one arm is directed against EGFR-D2 and the other is directed against EGFR-D3 (the Antibodies). Under the terms of the ELS Purchase Agreement, the Company made an upfront payment of $2.0 million and issued to ELS 500,000 shares of the Company’s common stock at a value of $3.36 per share or a total fair value of $1.7 million. Under the ELS Purchase Agreement, ELS is committed to performing certain studies on the applicable antibodies to assist in development activities, the costs of which shall be mutually agreed upon and for which the Company will be responsible. The Company recorded IPR&D expense of $0 and $3.7 million during the three and six months ended June 30, 2021 in connection with the asset acquisition.

Pursuant to the ELS Purchase Agreement, at any time between 12 months and 36 months after the effective date of the ELS Purchase Agreement, if the Company reasonably determines that none of the Antibodies should be taken into human clinical trials due to safety, efficacy or CMC issues, then the Company has the option to select another antibody developed and solely owned by ELS that is not the subject of a license, collaboration, or option to a third party (the Option). If the Company elects to exercise the Option, then ELS will provide to the Company a list of all available antibodies that meet the aforementioned requirements, and the Company has the right to select one antibody from the list. Upon the Company’s selection of an antibody, ELS will assign it all rights, title and interest to such antibody (including patent and other intellectual property rights) subject to any pre-existing obligations or restrictions. In the event that the Company wishes to have ELS conduct any studies on such optioned antibody, then after mutual agreement as to the scope of the studies, the Company will be responsible for the cost for such studies.

License Agreements

6 Months Ended

Jun. 30, 2021

License Agreements [Abstract]

License Agreements

Note 8. License agreements

NiKang Therapeutics, Inc.

In February 2020, the Company entered into a license agreement (the NiKang Agreement) with NiKang Therapeutics, Inc. (NiKang) under which the Company was granted an exclusive, worldwide license to certain intellectual property rights owned or controlled by NiKang related to certain SHP2 inhibitors to develop and commercialize ERAS-601 and certain other related compounds for all applications. The Company has the right to sublicense (through multiple tiers) its rights under the NiKang Agreement, subject to certain conditions, and is required to use commercially reasonable efforts to develop and commercialize licensed products. The parties are obligated to negotiate in good faith for a certain period of time to grant NiKang the exclusive commercial distribution rights in greater China once a licensed product reaches a certain development stage.

Under the NiKang Agreement, the Company made an upfront payment of $5.0 million to NiKang and reimbursed NiKang $0.4 million for certain initial manufacturing costs. In addition, the Company paid $7.0 million in April 2020 related to the publication of a US patent application that covered the composition of matter of ERAS-601. The Company is also obligated to pay (i) development and regulatory milestone payments in an aggregate amount of up to $16.0 million for the first licensed product and $12.0 million for a second licensed product, and (ii) commercial milestone payments in an aggregate amount of up to $157.0 million for the first licensed product and $151.0 million for a second licensed product. The Company is also obligated to: (i) pay tiered royalties on net sales of all licensed products in the mid-single digit percentages, subject to certain reductions; and (ii) equally split all net sublicensing revenues earned under sublicense agreements that the Company enters into with any third party

before commencement of the first Phase I clinical trial for a licensed product. As of June 30, 2021 and December 31, 2020, the Company had accrued $0 and $4.0 million related to a development milestone, respectively. The Company recorded IPR&D expense of $0 during the three and six months ended June 30, 2021 and $0 and $12.0 million during the three and six months ended June 30, 2020, respectively, related to the upfront and milestone payments.

The NiKang Agreement will expire upon the last to expire royalty term, which is determined on a licensed product-by-licensed product and country-by-country basis, and is the later of (i) ten years from the date of first commercial sale, (ii) the last to expire valid claim within the licensed patent rights covering such licensed product, or (iii) the expiration of all regulatory exclusivity for the licensed product in such country. Upon expiration of the NiKang Agreement, on a licensed product-by-licensed product and country-by-country basis, the Company will have a fully paid-up, non-exclusive license to conduct research and to develop and commercialize the licensed products.

The NiKang Agreement may be terminated in its entirety by NiKang in the event of the Company’s uncured material breach, which includes its failure to use commercially reasonable efforts to satisfy certain specified clinical development diligence milestones. In addition, NiKang may terminate if the Company, directly or indirectly, commences a legal action challenging the validity or enforceability of any licensed patents. Further, if the Company acquires more than 50% of the equity or assets of a company that owns a competing small molecule that is designed to prevent the same target as set forth in the NiKang Agreement from switching to an enzymatically active state, then the Company must either divest such competing product or terminate the NiKang Agreement. The Company may terminate the NiKang Agreement at any time upon the provision of prior written notice to NiKang. Upon termination of the NiKang Agreement for any reason, all rights and licenses granted to the Company, as well as any sublicenses that the Company granted thereunder, will terminate. In addition, upon any termination (but not expiration) of the NiKang Agreement and upon NiKang’s request, the parties are obligated to meet and negotiate in good faith the terms of a license from the Company to NiKang to allow NiKang’s continued development, manufacture, and commercialization of the licensed products.

Katmai Pharmaceuticals, Inc.

In March 2020, the Company entered into a license agreement (the Katmai Agreement) with Katmai Pharmaceuticals, Inc. (Katmai) under which the Company was granted an exclusive, worldwide, royalty-bearing license to certain patent rights and know-how controlled by Katmai related to the development of small molecule therapeutic and diagnostic products that modulate EGFR and enable the identification, diagnosis, selection, treatment, and/or monitoring of patients for neuro-oncological applications to develop, manufacture, use, and commercialize ERAS-801 and certain other related compounds in all fields of use. The Company has the right to sublicense (through multiple tiers) its rights under the Katmai Agreement, subject to certain limitations and conditions, and is required to use commercially reasonable efforts to develop, manufacture, and commercialize licensed products and to meet certain specified development and launch milestones by certain dates. The Company is obligated to use commercially reasonable efforts to develop the licensed products first for use within the neuro-oncology field before expanding its development efforts to include other indications in the oncology field. Following the first achievement of a clinical proof-of-concept for any indication, the Company has the right to submit a non-binding offer to Katmai for (i) the purchase of all licensed patent rights, know-how, and other assets owned by Katmai that are necessary or useful for the exploitation of the licensed products or (ii) for the purchase of Katmai. Pursuant to the Katmai Agreement, neither Katmai nor the Company can directly or indirectly exploit certain specified classes of competing products.

The license granted under the Katmai Agreement is subject to The Regents of the University of California’s reserved right to (i) use the licensed patent rights and know-how for educational and non-commercial research purposes, and to publish results arising therefrom, and (ii) grant licenses to the licensed know-how to third parties without notice because the licensed know-how is non-exclusively licensed to Katmai by The Regents of the University of California. Further, the license granted under the Katmai Agreement is subject to the rights of the United States government under the Bayh-Dole Act, including (i) a non-exclusive, non-transferable, irrevocable, paid-up license to practice or have practiced the invention claimed by the licensed patent rights throughout the world and (ii) the obligation that any licensed products used or sold in the United States be manufactured substantially in the United States.

Under the Katmai Agreement, the Company made an upfront payment of $5.7 million and Katmai agreed to purchase shares of the Company’s Series B-1 convertible preferred stock and Series B-2 convertible preferred stock having an aggregate value of $2.7 million. In April 2020, Katmai purchased 356,000 shares of the Company’s Series B-1 convertible preferred stock for $1.8 million, and in January 2021, Katmai purchased 118,666 shares of the Company’s Series B-2 convertible preferred stock for $0.9 million. The Company is obligated to make future development and regulatory milestone payments of up to $26.0 million and commercial milestone payments of up to $101.0 million. The Company is also obligated to pay tiered royalties on net sales of each licensed product, at rates ranging from the mid- to high-single digit percentages, subject to a minimum annual royalty

payment in the low six figures and certain permitted deductions. No IPR&D expense was recorded for the three and six months ended June 30, 2021. The Company recorded IPR&D expense of $0 and $5.7 million in connection with the upfront payment during the three and six months ended June 30, 2020, respectively.

The Company’s royalty obligations and the Katmai Agreement will expire, on a licensed product-by-licensed product and country-by-country basis, on the earlier of (i) the ten-year anniversary of the expiration of all valid claims included in the licensed patents covering the composition of matter or method of use of such licensed product in such country or (ii) the twentieth anniversary of the first commercial sale of such licensed product in such country. Upon the expiration of the Katmai Agreement, the Company will have a fully paid-up and irrevocable license.

The Katmai Agreement may be terminated in its entirety by either party (i) in the event of an uncured material breach by the other party or (ii) in the event the other party becomes subject to specified bankruptcy, insolvency, or similar circumstances. Provided that the Company is in full compliance with the Katmai Agreement, the Company may terminate the Katmai Agreement upon written notice to Katmai. Upon termination of the Katmai Agreement for any reason, all rights and licenses granted to the Company thereunder will terminate. Upon termination of the Katmai Agreement, the Company is obligated, among other things, to (i) grant an exclusive license to Katmai under all of the Company’s right, title and interest in all inventions and know-how developed under the Katmai Agreement existing at the time of termination that are specific to the licensed compounds or products, including without limitation all data and results related to Katmai’s exploitation and (ii) transfer to Katmai ownership and possession of all regulatory filings related to the licensed compounds and products. Unless the Katmai Agreement is terminated for the Company’s material breach, the parties will negotiate in good faith the financial terms pursuant to which the foregoing actions will be conducted, provided that the Company’s performance of such actions may not be conditioned upon the conduct or completion of such negotiations. If the parties are unable to agree upon such terms within the specified time period, then the parties will submit all unresolved matters for resolution by arbitration.

LifeArc

In April 2020, the Company entered into a license agreement with LifeArc (the LifeArc Agreement) under which the Company was granted an exclusive, worldwide license to certain materials, know-how, and intellectual property rights owned or controlled by LifeArc to develop, manufacture, use, and commercialize certain ULK inhibitors for all applications. The Company also has the right to sublicense (through multiple tiers) its rights under the LifeArc Agreement, subject to certain conditions. The foregoing license is subject to LifeArc’s retained non-exclusive, irrevocable, worldwide, sublicensable (to its academic collaborators), royalty-free right to use the licensed intellectual property rights within all fields of use for LifeArc’s own non-commercial, non-clinical academic research. Notwithstanding its retained rights, LifeArc will not seek to develop or undertake any other ULK1/2 therapeutic development programs either in-house or via third parties until April 2025. The Company is required to use diligent efforts to achieve certain development and regulatory milestones with respect to submission of an IND, initiation of clinical trials, submission of an NDA, and commencement of commercial sales.

Under the LifeArc Agreement, the Company was granted the license at no upfront cost and a period of three months after the effective date to conduct experiments on LifeArc’s compounds. Upon completion of this initial testing period, the Company had the option to continue the license and make a one-time license payment of $75,000 to LifeArc, which payment was subsequently made. The Company is obligated to make future development milestone payments for a licensed product of up to $11.0 million and sales milestone payments of up to $50.0 million. The Company is also obligated to pay royalties on net sales of all licensed products, in the low-single digit percentages, subject to certain reductions. No IPR&D expense was recorded during the three and six months ended June 30, 2021 and 2020.

The Company’s royalty obligations and the LifeArc Agreement will expire, on a licensed product-by-licensed product and country-by-country basis, on the later of (i) ten years from the date of first commercial sale, (ii) when there is no longer a valid patent claim covering such licensed product, or (iii) expiration of regulatory exclusivity for the licensed product in such country. Upon expiration of the LifeArc Agreement, all rights and licenses granted to the Company and under the LifeArc Agreement will continue on a fully paid-up basis.

The LifeArc Agreement may be terminated in its entirety by either LifeArc or the Company in (i) the event of an uncured material breach by the other party or (ii) in the event the other party becomes subject to an order by a court of competent jurisdiction for winding-up or dissolution or similar circumstances. Further, LifeArc may terminate the LifeArc Agreement by giving written notice to the Company if (i) the Company fails to comply with its diligence obligations and fails to take remedial actions, (ii) the Company fails to agree on a mechanism to cure a persistent breach, or (iii) the Company fails to provide proof of the insurance coverage as required under the LifeArc Agreement. The Company may terminate the agreement at any time upon the provision of written notice to LifeArc.

Upon termination of the LifeArc Agreement for any reason, all rights and licenses granted to the Company, as well as any sublicenses the Company granted thereunder, will terminate. In addition, upon termination of the LifeArc Agreement for any reason other than its natural expiration or termination by the Company for LifeArc’s material breach, LifeArc has an option to negotiate an exclusive, worldwide, sublicensable license to commercialize any patent rights, technical and clinical data, and any development results relating to the licensed products that are owned or controlled by the Company for the purpose of developing, manufacturing and commercializing the licensed products on terms to be negotiated between the parties.

University of California, San Francisco

In December 2018, the Company entered into a license agreement, as amended (the UCSF Agreement), with The Regents of the University of California, San Francisco (the Regents), under which the Company was granted an exclusive, worldwide, royalty-bearing license under certain patent rights claiming novel covalent inhibitors of GTP- and GDP-bound RAS for the development and commercialization of products covered by such patent rights for the prevention, treatment and amelioration of human cancers and other diseases and conditions. The UCSF Agreement was amended in May 2021. The Company has the right to sublicense (through multiple tiers) its rights under the UCSF Agreement, subject to certain conditions. The foregoing license is subject to various retained rights and restrictions, including (i) the Regents’ reserved right to make, use and practice the licensed patent rights and any technology relating thereto for educational and research purposes, (ii) Howard Hughes Medical Institute’s non-exclusive, fully paid-up, irrevocable worldwide license to use the licensed patent rights for research purposes, (iii) Howard Hughes Medical Institute’s statement of policy on research tools, and (iv) the obligations to the US government under the Bayh-Dole Act, including the obligation to report on the utilization of the invention covered by the licensed patent rights and a non-exclusive, non-transferable, irrevocable, paid-up license to practice or have practiced such invention throughout the world. The Company is required to use diligent efforts to proceed with the development and commercialization of licensed products including by achieving certain milestone events within the specified time periods.

Under the UCSF Agreement, the Company made upfront payments of $50,000 to the Regents and pays the Regents an annual license maintenance fee during the term of the license, but such fee will not be due on any anniversary if, on that date, the Company is making royalty payments to the Regents. The Company is obligated to make future development and regulatory milestone payments of up to $6.4 million and a sales milestone payment of $2.0 million for either of the first two licensed products. The Company is also obligated to pay royalties on net sales of all licensed products in the low-single digit percentages, subject to a minimum annual royalty payment in the low six figures, commencing on the year of the first sale of a licensed product and continuing, on a licensed product-by-licensed product and country-by-country basis, until there are no valid claims of the licensed patent rights covering the licensed product in such country.

Additionally, the Company is obligated to pay tiered sublicensing fees, with the first two tiers in the low-to-mid teen percentages and the third tier at 30%, on certain fees the Company receives from any sublicense that the Company grants, depending on the stage of development of a licensed product when such sublicense is granted. Prior to the execution of the amendment, the Company was obligated to make a cash payment to the Regents in the event of the Company’s initial public offering, a change of control transaction or a reverse merger (the Corporate Milestone). In the amendment, the amount of the cash payment payable upon the Company’s achievement of a Corporate Milestone was reduced and the Company agreed to issue the Regents 944,945 shares of the Company’s common stock, which issuance is not contingent upon the achievement of a Corporate Milestone and occurred in May 2021. The Company recorded IPR&D expense of $5.5 million during the three and six months ended June 30, 2021 related to the issuance of these 944,945 common stock shares. No IPR&D expense was recorded during the three and six months ended June 30, 2020.

The UCSF Agreement will expire upon the expiration of the last of the licensed patent rights. The UCSF Agreement may be terminated in its entirety by the Regents (i) for the Company’s uncured breach; (ii) for the Company’s bankruptcy; or (iii) if the Company challenges, directly or indirectly, the validity or enforceability of any licensed patents. Further, if the Company fails to satisfy any diligence milestones, the Regents has the right and option to either terminate the UCSF Agreement or modify the exclusive license granted thereunder to a non-exclusive license. The Company may terminate the UCSF Agreement in its entirety or on a country-by-country basis at any time upon the provision of written notice to the Regents. Upon termination of the UCSF Agreement for any reason, all rights and licenses granted to the Company thereunder will terminate.

Stockholders' Deficit

6 Months Ended

Jun. 30, 2021

Equity [Abstract]

Stockholders' Deficit

Note 9. Stockholders’ deficit

Under its Amended and Restated Certificate of Incorporation dated April 15, 2020, the Company was authorized to issue 147,027,681 shares of its common stock, par value of $0.0001 per share. In February 2021, the Company’s Board of Directors increased the authorized number of shares of its common stock to 156,000,000 shares. As of June 30, 2021, the Company was authorized to issue 97,622,409 shares of its convertible preferred stock, par value of $0.0001 per share, of which 38,103,681 shares are designated as Series A convertible preferred stock, 28,741,400 shares are designated as Series B-1 convertible preferred stock and 30,777,328 shares are designated as Series B-2 convertible preferred stock.

Convertible preferred stock

In 2018, the Company issued 27,953,681 shares of its Series A convertible preferred stock at $1.667 per share. The Company received proceeds of approximately $46.5 million, net of issuance costs.

In 2019, the Company issued 10,150,000 shares of its Series A convertible preferred stock at $1.667 per share. The Company received proceeds of approximately $16.9 million, net of issuance costs.

In April 2020, the Company entered into a Series B convertible preferred stock purchase agreement (the Series B Agreement) under which it issued 27,481,001 shares of its Series B-1 convertible preferred stock at various closing dates in 2020, for cash, at a price of $5.00 per share, for net proceeds of $137.0 million (the Series B-1 Closing). The Series B Agreement contained provisions that potentially obligates the Company to issue 13,175,191 shares of Series B-2 convertible preferred stock at $7.50 per share in an additional closing to certain Series B-1 Closing purchasers, upon the achievement of certain milestones as defined in the Series B Agreement, which purchase right terminates on September 30, 2022 or at certain specified events, including an initial public offering of the Company, if any (the Series B-2 Closing). In the event that a Series B-1 Closing purchaser fails to purchase all of its required shares in the subsequent Series B-2 Closing, each of the Series B-1 convertible preferred shares held by such purchaser will automatically be converted into one-tenth of a share of the Company’s common stock.

The Company determined its obligation to issue additional shares of its Series B-2 convertible preferred stock in the Series B-1 Closing represented a freestanding financial instrument that required liability accounting. This freestanding preferred stock purchase right liability for the Series B-2 Closing was recorded at fair value and is remeasured at each reporting period. As of the Series B-1 Closing, the estimated fair value of the preferred stock purchase right liability was $9.0 million. The Company records any changes in the fair value of the Series B-2 convertible preferred stock purchase right liability as changes in the fair value of convertible preferred stock purchase right liability in the accompanying consolidated statements of operations and comprehensive loss, and recorded a gain of $7.4 million for the year ended December 31, 2020. To satisfy its obligation, in January 2021, the Company sold 13,175,191 shares of its Series B-2 convertible preferred stock and an additional 2,756,581 shares of its Series B-2 convertible preferred stock at a price of $7.50 per share and received aggregate net proceeds of $119.4 million.

Also in 2020, the Company issued 4,000,000 shares of its Series B-2 convertible preferred stock at $7.50 per share in connection with an asset acquisition (see Note 7).

Convertible preferred stock consisted of the following (in thousands, except share data):


	June 30, 2021
	Preferred		Preferred shares						Common stock
	shares		issued and		Carrying		Liquidation		issuable upon
	authorized		outstanding		value		preference		conversion
Series A preferred stock		38,103,681		38,103,681	$	63,403	$	63,519		31,753,064
Series B-1 preferred stock		28,741,400		27,481,001		128,002		137,405		22,900,819
Series B-2 preferred stock		30,777,328		19,931,772		149,393		149,488		16,609,802
Total		97,622,409		85,516,454	$	340,798	$	350,412		71,263,685


	December 31, 2020
	Preferred		Preferred shares						Common stock
	shares		issued and		Carrying		Liquidation		issuable upon
	authorized		outstanding		value		preference		conversion
Series A preferred stock		38,103,681		38,103,681	$	63,403	$	63,519		31,753,064
Series B-1 preferred stock		28,741,400		27,481,001		128,002		137,405		22,900,819
Series B-2 preferred stock		30,777,328		4,000,000		30,000		30,000		3,333,333
Total		97,622,409		69,584,682	$	221,405	$	230,924		57,987,216

Convertible preferred stock rights and preferences

The rights and preferences for convertible preferred stock are detailed in the Company’s final prospectus filed with the Securities and Exchange Commission pursuant to Rule 424(b)(4) under the Securities Act of 1933, as amended, on July 16, 2021.

Common stock

The Company had 156,000,000 and 147,027,681 shares of its common stock authorized as of June 30, 2021 and December 31, 2020, respectively. The Company had 27,300,123 and 25,189,673 shares of its common stock issued and 24,370,599 and 21,923,173 shares of common stock outstanding as of June 30, 2021 and December 31, 2020, respectively. As of June 30, 2021 and December 31, 2020, the fair value of common stock was $9.28 and $3.36, respectively.

Shares of common stock subject to repurchase

During 2018, the Company issued 1,458,332 shares of restricted stock for cash at a price of $0.0001 per share. The restricted stock vests 25% one year from the vesting commencement date and monthly thereafter over a three-year period and is subject to repurchase by the Company in the event of any voluntary or involuntary termination of services to the Company prior to vesting. Any shares subject to repurchase by the Company are not deemed, for accounting purposes, to be outstanding until those shares vest. As of June 30, 2021 and December 31, 2020, 394,966 shares and 577,259 shares of common stock, respectively, were subject to repurchase by the Company. The unvested stock liability related to these awards is immaterial for all periods presented. For the three and six months ended June 30, 2021, 91,146 and 182,293 shares vested, respectively. For the three and six months ended June 30, 2020, 91,146 and 182,292 shares vested, respectively.

Stock-based Compensation

6 Months Ended

Jun. 30, 2021

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-based Compensation

Note 10. Stock-based compensation

In July 2018, the Company adopted the 2018 Equity Incentive Plan (the Plan), which expires ten years from its effective date. The Plan provides for the grant of incentive stock options, non-statutory stock options, restricted stock awards, restricted stock unit awards, and other stock awards to employees, consultants and directors of the Company. As of June 30, 2021 and December 31, 2020, a total of 21,545,845 and 13,212,511 shares of common stock, respectively, were authorized for issuance under the Plan.

Options granted under the Plan are exercisable at various dates as determined upon grant and will expire no more than ten years from their date of grant. Stock options generally vest over a four-year term. The exercise price of each option shall be determined by the Company’s Board of Directors based on the estimated fair value of the Company’s stock on the date of the option grant. The exercise price shall not be less than 100% of the fair market value of the Company’s common stock at the time the option is granted. For holders of more than 10% of the Company’s total combined voting power of all classes of stock, incentive stock options may not be granted at less than 110% of the fair market value of the Company’s common stock on the date of grant and for a term that exceeds five years. Early exercise is permitted for certain grants.

Stock options

A summary of the Company’s stock option activity under the Plan is as follows (in thousands, except share and per share data and years):


						Weighted-
				Weighted-		average remaining		Aggregate
				average		contractual		intrinsic
	Shares			exercise price		term (years)		value
Outstanding at December 31, 2020		6,541,422		$	0.98		9.23	$	15,571
Granted		7,658,023			4.92
Exercised		(665,505	)		1.99				1,984
Canceled		(8,333	)		5.81
Outstanding at June 30, 2021		13,525,607		$	3.16		9.24	$	82,735
Options exercisable at June 30, 2021		1,902,188		$	1.97		8.87	$	13,903

The weighted-average grant date fair value of options granted for the three and six months ended June 30, 2021 was $4.59 and $3.45, respectively, and for the three and six months ended June 30, 2020 was $0 and $0.45, respectively. As of June 30, 2021, the unrecognized compensation cost related to unvested stock option grants was $29.3 million and is expected to be recognized as expense over approximately 3.68 years. The aggregate fair value of stock options that vested for the three and six months ended June 30, 2021 was $0.5 million and $0.8 million, respectively, and for the three and six months ended June 30, 2020 was $0.1 million.

Certain individuals were granted the ability to early exercise their stock options. The shares of common stock issued from the early exercise of unvested stock options are restricted and continue to vest in accordance with the original vesting schedule. The Company has the option to repurchase any unvested shares at the original purchase price upon any voluntary or involuntary termination. The shares purchased by the employees and non-employees pursuant to the early exercise of stock options are not deemed, for accounting purposes, to be outstanding until those shares vest. The cash received in exchange for exercised and unvested shares related to stock options granted is recorded as a liability for the early exercise of stock options on the accompanying consolidated balance sheets and will be transferred into common stock and additional paid-in capital as the shares vest. As of June 30, 2021 and December 31, 2020, there were 2,149,221 shares and 2,131,510 shares subject to repurchase by the Company, respectively. As of June 30, 2021 and December 31, 2020, the Company recorded $3.2 million and $2.5 million of liabilities associated with shares issued with repurchase rights, respectively, which is recorded in accrued expenses and other current liabilities.

In January 2019, the Company granted 250,000 options that vest based on a performance milestone. For the three and six months ended June 30, 2021, the Company recognized $22,000 and $115,000 of stock-based compensation associated with the performance-based options as the performance milestone was determined to be probable as of March 31, 2021. As of December 31, 2020, the milestone for the performance-based options was not probable of achievement, and therefore, no compensation expense for performance-based options had been recognized.

The assumptions used in the Black-Scholes option pricing model to determine the fair value of the employee and nonemployee stock option grants were as follows:


	Three months ended June 30,		Six months ended June 30,
	2021	2020(1)	2021	2020
Risk-free interest rate	1.02%-1.09%	--%	0.59%-1.09%	1.22%
Expected volatility	82.08%-82.54%	--%	82.08%-83.88%	74.72%
Expected term (in years)	6.08	0.00	6.08	6.25
Expected dividend yield	--%	--%	--%	--%

(1)

No stock options were granted during the three months ended June 30, 2020.

Restricted stock

The Company granted 1,795,827 shares of its restricted stock in 2018, which vest 25% one year from the vesting commencement date and monthly thereafter over a three-year period. The weighted-average grant date fair value of restricted stock granted in 2018 was $0. No shares of restricted stock were granted during the three and six months ended June 30, 2021 and 2020. The restricted stock shares are subject to forfeiture upon the stockholders’ termination of employment or service to the Company. Any shares subject to forfeiture are not deemed, for accounting purposes, to be outstanding until those shares vest. As such, the Company recognizes the measurement date fair value of the restricted stock over the vesting period as compensation expense. As of June 30, 2021 and December 31, 2020, 385,337 shares and 557,731 shares of common stock, respectively, were subject to forfeiture.

The summary of the Company’s restricted stock activity during the six months ended June 30, 2021 is as follows:


	Number of			Weighted-
	restricted			average
	stock shares			grant date
	outstanding			fair Value
Nonvested at December 31, 2020		557,731		$	0.001
Vested		(172,394	)		0.001
Nonvested at June 30, 2021		385,337		$	0.001

At June 30, 2021, the total unrecognized compensation related to unvested restricted stock awards granted was $0.

Stock-based compensation expense

The allocation of stock-based compensation for all stock awards was as follows (in thousands):


	Three months ended June 30,				Six months ended June 30,
	2021		2020		2021		2020
Research and development	$	925	$	52	$	1,416	$	101
General and administrative		711		57		1,015		113
Total	$	1,636	$	109	$	2,431	$	214

Common stock reserved for future issuance

Common stock reserved for future issuance consisted of the following as of June 30, 2021 and December 31, 2020:


	June 30,		December 31,
	2021		2020
Conversion of preferred stock outstanding		71,263,685		57,987,216
Conversion of preferred stock in future issuance (B-2)	—			10,979,319
Stock options issued and outstanding		13,525,607		6,541,422
Awards available for future grant		2,998,389		2,314,746
Total		87,787,681		77,822,703

Leases

6 Months Ended

Jun. 30, 2021

Leases [Abstract]

Leases

Note 11. Leases

Operating leases

The Company has facility leases for office space under non-cancellable and cancelable operating leases with various expiration dates through 2032 and equipment under a non-cancellable operating lease with a term expiring in 2022. Operating lease cost was approximately $380,000 and $742,000, including variable lease costs of $123,000 and $228,000, and short-term lease costs of $30,000 and $59,000 during the three and six months ended June 30, 2021, respectively. Operating lease cost was approximately $321,000 and $661,000, including variable lease costs of $78,000 and $175,000, and short-term lease costs of $22,000 and $41,000 during the three and six months ended June 30, 2020, respectively. The Company paid $535,000 and $470,000 in cash for operating leases that were included in the operating activities section of the consolidated statements of cash flows for the six months ended June 30, 2021 and 2020, respectively.

The weighted-average remaining lease term and the weighted-average discount rate of the Company’s operating leases was 2.71 years and 7.8% at June 30, 2021, respectively. The weighted-average remaining lease term and the weighted-average discount rate of the Company’s operating leases was 3.16 years and 7.8% at December 31, 2020, respectively. The weighted-average remaining lease term does not include any renewal options at the election of the Company.

The Company’s lease agreements do not contain any material residual value guarantees or material restrictive covenants.

Facility leases

In 2018, the Company entered into a lease agreement for approximately 11,000 square feet of office space in San Diego, California which was subsequently amended resulting in a total of approximately 16,153 square feet of office space leased. The amended space is accounted for as a separate lease. The non-cancellable operating leases expire in May 2024. The Company’s lease payments consist primarily of fixed rental payments for the right to use the underlying leased assets over the lease terms. The Company is responsible for operating expenses over base operating expenses as defined in the original lease agreement.

In September 2020, the Company entered into a lease agreement for 59,407 square feet of laboratory and office space in San Diego, California (2020 Lease), which represented a portion of a new facility that is under construction. The construction and design of the asset is the primary responsibility of the lessor. The Company is involved in certain aspects of construction and design for certain interior features and leasehold improvements that will be beneficial to the Company to better suit its business needs and intended purpose of the space. The lease will be accounted for as an operating lease and has a target commencement date of August 2021. The lease has an initial term of 10.5 years and includes aggregate monthly payments to the lessor of approximately $39.5 million beginning in January 2023 with a rent escalation clause, and a tenant improvement allowance of approximately $13.4 million. The lease is cancellable at the Company’s request after the 84th month with 12 months written notice and a lump-sum cancellation payment of $1.9 million. As discussed in Note 2, the Company provided a letter of credit to the lessor for $312,000, which expires October 31, 2031.

In March 2021, the Company entered into the first amendment to the 2020 Lease to expand the rented premises by 18,421 square feet for additional consideration of $96,000 per month starting in January 2023 with a rent escalation clause and to receive an additional $3.4 million tenant improvement allowance. The payment associated with the option to cancel the lease after the 84th month was increased to $2.5 million, and the letter of credit provided to the lessor was increased to $408,000.

Future minimum lease payments under non-cancelable operating leases with initial lease terms in excess of one year as of June 30, 2021 are as follows (in thousands):


Year ending December 31,
2021 (6 months remaining)	$	538
2022		969
2023		937
2024		401
Total lease payments	$	2,845
Less: Amount representing interest		(288	)
Operating lease liabilities	$	2,557

As of June 30, 2021, the Company had commitments of $51.6 million for a cancelable operating lease of a new real estate facility that has not yet commenced, and therefore are not included in the operating lease assets or liabilities. This operating lease commenced in August 2021 with a lease term of 10.5 years.

Commitments and Contingencies

6 Months Ended

Jun. 30, 2021

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

Note 12. Commitments and contingencies

As of June 30, 2021 and December 31, 2020, there was no litigation against the Company.

Income Taxes

6 Months Ended

Jun. 30, 2021

Income Tax Disclosure [Abstract]

Income Taxes

Note 13. Income taxes

No provision for federal, state or foreign income taxes has been recorded for the three and six months ended June 30, 2021 and 2020. The Company has incurred net operating losses for all the periods presented and has not reflected any benefit of such net operating loss carryforwards in the accompanying consolidated financial statements due to uncertainty around utilizing these tax attributes within their respective carryforward periods. The Company has recorded a full valuation allowance against all of its deferred tax assets as it is not more likely than not that such assets will be realized in the near future. The Company’s policy is to recognize interest expense and penalties related to income tax matters as tax expense. For the three and six months ended June 30, 2021 and 2020, the Company has not recognized any interest or penalties related to income taxes.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References + Details

Net Loss Per Share

6 Months Ended

Jun. 30, 2021

Earnings Per Share [Abstract]

Net Loss Per Share

Note 14. Net loss per share

The following table summarizes the computation of basic and diluted net loss per share of the Company (in thousands, except share and per share data):


	Three months ended June 30,						Six months ended June 30,
	2021			2020			2021			2020
Net loss	$	(28,214	)	$	(5,491	)	$	(46,231	)	$	(29,149	)
Weighted-average shares of common stock used in computing net loss per share, basic and diluted		23,546,390			20,834,976			22,893,533			20,733,283
Net loss per share, basic and diluted	$	(1.20	)	$	(0.26	)	$	(2.02	)	$	(1.41	)

The Company’s potentially dilutive securities, which include its convertible preferred stock, options to purchase common stock and common stock subject to repurchase related to unvested restricted stock and options early exercised, have been excluded from the computation of diluted net loss per share as the effect would be to reduce the net loss per share. Therefore, the weighted-average number of common shares outstanding used to calculate both basic and diluted net loss per share is the same. The Company excluded the following potential common shares, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share for the periods indicated because including them would have had an anti-dilutive effect:


	Three months ended June 30,				Six months ended June 30,
	2021		2020		2021		2020
Convertible preferred stock issued		71,263,685		52,653,884		71,263,685		52,653,884
Conversion of convertible preferred stock in future issuance (B-2)	—			8,312,653	—			8,312,653
Options to purchase common stock		13,525,607		3,390,918		13,525,607		3,390,918
Restricted stock subject to future vesting		780,303		1,706,689		780,303		1,706,689
Options early exercised subject to future vesting		2,149,221		729,166		2,149,221		729,166
Total potentially dilutive shares		87,718,816		66,793,310		87,718,816		66,793,310

Retirement Plan

6 Months Ended

Jun. 30, 2021

Compensation And Retirement Disclosure [Abstract]

Retirement Plan

Note 15. Retirement plan

The Company sponsors an employee savings plan that qualifies as a deferred salary arrangement under Section 401(k) of the IRC. Participating employees may defer up to the Internal Revenue Service annual contribution limit. Beginning in 2021, the Company provides a safe harbor contribution of 3.0% of the employee’s compensation, not to exceed eligible limits. For the three and six months ended June 30, 2021, the Company incurred $105,000 and $232,000 in expenses related to the safe harbor contribution, respectively. No expenses were incurred for the three and six months ended June 30, 2020 related to the safe harbor contribution.

- Definition

The entire disclosure for retirement benefits.

+ References

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+ Details

COVID-19 pandemic

6 Months Ended

Jun. 30, 2021

Risks and Uncertainties [Abstract]

COVID-19 Pandemic

Note 16. COVID-19 pandemic

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. During the three and six months ended June 30, 2021 and 2020, the Company has not experienced significant impact from the pandemic. 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.

Subsequent Events

6 Months Ended

Jun. 30, 2021

Subsequent Events [Abstract]

Subsequent Events

Note 17. Subsequent events

Reverse stock split

On July 9, 2021, the Company effected a one-for-1.2 reverse stock split of its issued and outstanding shares of common stock and a proportional adjustment to the existing conversion ratios for each series of the Company’s Preferred Stock. Accordingly, all share and per share amounts for all periods presented in the accompanying consolidated financial statements and notes thereto have been adjusted retroactively, where applicable, to reflect this reverse stock split and adjustment of the preferred stock conversion ratios. The par value and the number of authorized shares of the convertible preferred stock and common stock were not adjusted in connection with the reverse stock split.

Initial public offering

On July 20, 2021, the Company completed its IPO in which the Company issued and sold 21,562,500 shares of common stock (including 2,812,500 shares of common stock in connection with the full exercise of the underwriters’ option to purchase additional shares) at an offering price of $16.00 per share. Proceeds from the IPO, net of underwriting discounts, commissions and estimated offering costs, were $317.7 million. In connection with the completion of the IPO, all outstanding shares of convertible preferred stock were converted into 71,263,685 shares of common stock.

Erasca Foundation

In May 2021, the Company established the Erasca Foundation to provide support such as direct research grants, hardship grants, patient advocacy, patient education in underserved populations, and funding for other initiatives to positively impact society. In July 2021, the Company issued 1,093,557 shares of its common stock to the Erasca Foundation.

Amendment of certificate of incorporation

In connection with the IPO, on July 20, 2021, the Company amended and restated its certificate of incorporation to, among other things, (i) increase the number of authorized shares of common stock from 156,000,000 to 800,000,000 and (ii) authorize 80,000,000 shares of undesignated preferred stock with a par value of $0.0001.

2021 Incentive award plan

In July 2021, the Company’s board of directors adopted and the Company’s stockholders approved the Company’s 2021 Incentive Award Plan (the 2021 Plan), which became effective in connection with the IPO. Under the 2021 Plan, the Company may grant stock options, restricted stock, restricted stock units, stock appreciation rights, and other stock or cash-based awards to individuals who are then employees, officers, directors or non-entity consultants of the Company. A total of 15,150,000 shares of common stock were initially reserved for issuance under the 2021 Plan. In addition, the number of shares of common stock available for issuance under the 2021 Plan will be increased annually on the first day of each fiscal year during the term of the 2021 Plan, beginning with the 2022 fiscal year, by an amount equal to the lesser of (a) 5% of the shares of common stock outstanding on the final day of the immediately preceding calendar year or (b) such smaller number of shares as determined by the Company’s board of directors.

Employee stock purchase plan

In July 2021, the Company’s board of directors adopted and the Company’s stockholders approved the Company’s 2021 Employee Stock Purchase Plan (the ESPP), which became effective in connection with the IPO. The ESPP permits participants to contribute up to a specified percentage of their eligible compensation during defined rolling six-month periods to purchase the Company’s common stock. The purchase price of the shares will be 85% of the lower of the fair market value of the Company’s common stock on the first day of trading of the offering period or on the applicable purchase date. A total of 1,260,000 shares of common stock was initially reserved for issuance under the ESPP.

UCSF Agreement amendment

In connection with the UCSF Agreement amendment, in August 2021, following the achievement of the Corporate Milestone, the Company made a cash payment to the Regents in the amount of $1.7 million.

Summary of Significant Accounting Policies (Policies)

6 Months Ended

Jun. 30, 2021

Accounting Policies [Abstract]

Use of Estimates

Use of estimates

Unaudited Interim Financial Information

Unaudited interim financial information

June 30, 2021 are not necessarily indicative of results to be expected for the year ending December 31, 2021, any other interim periods, or any future year or period.

Concentration of Credit Risk and Off-Balance Sheet Risk

Concentration of credit risk and off-balance sheet risk

Cash, Cash Equivalents and Restricted Cash

Cash, cash equivalents and restricted cash


	June 30,
	2021		2020
Cash and cash equivalents	$	156,396	$	104,339
Restricted cash		408		—
Total cash, cash equivalents and restricted cash as shown on the condensed consolidated statements of cash flows	$	156,804	$	104,339

Investments

Fair Value Measurements

Fair value measurements

Level 1—Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities.

Level 3—Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity).

Property and Equipment, Net

Property and equipment, net

Impairment of Long-Lived Assets

Impairment of long-lived assets

Leases

Research and Development Expense

Research and development expense

In-Process Research and Development Expense

In-process research and development expense

Patent Costs

Patent costs

Deferred Offering Costs

Deferred offering costs

deferred offering costs were recorded in other assets on the Company’s condensed consolidated balance sheet. There were no deferred offering costs as of December 31, 2020.

Common Stock Valuation

Common stock valuation

Share-based Compensation

Stock-based compensation

• Risk-free interest rate. The risk-free interest rate is based on the US Treasury zero-coupon issues in effect at the time of grant for periods corresponding with the expected term of the options.

The fair value of each restricted common stock award is estimated on the date of grant based on the fair value of the Company’s common stock on that same date.

Classification and Accretion of Convertible Preferred Stock

Classification and accretion of convertible preferred stock

Preferred Stock Purchase Right Liabilities

Preferred stock purchase right liabilities

Income Taxes

Income taxes

Comprehensive Income (Loss)

Comprehensive income (loss)

investments. Other comprehensive income includes unrealized gains and losses on investments, which was the only difference between net loss and comprehensive loss for the applicable periods.

Net Loss Per Share

Net loss per share

Segments

Recently Adopted Accounting Pronouncements and Recently Issued Accounting Pronouncements Not Yet Adopted

Recently adopted accounting pronouncements

Recently issued accounting pronouncements not yet adopted

Summary of Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2021

Accounting Policies [Abstract]

Reconciliation of Cash, Cash Equivalents and Restricted Cash


	June 30,
	2021		2020
Cash and cash equivalents	$	156,396	$	104,339
Restricted cash		408		—
Total cash, cash equivalents and restricted cash as shown on the condensed consolidated statements of cash flows	$	156,804	$	104,339

Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2021

Fair Value Disclosures [Abstract]

Summary of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis


			Fair value measurements as of June 30, 2021 using
			Quoted prices in		Significant		Significant
			active markets		other		unobservable
			for identical		observable		inputs
	June 30, 2021		assets (level 1)		inputs (level 2)		(level 3)
Assets:
Money market funds(1)	$	150,184	$	150,184	$	—	$	—
US treasury securities(2)		5,000		5,000		—		—
US government securities(2)		5,053		—		5,053		—
Corporate debt securities(2)		3,328		—		3,328		—
Commercial paper(2)		22,380		—		22,380		—
Supranational debt securities(2)		1,516		—		1,516		—
US government securities(3)		5,000		—		5,000		—
Total fair value of assets	$	192,461	$	155,184	$	37,277	$	—

(1)

Included as cash and cash equivalents on the condensed consolidated balance sheets.

(2)

Included as short-term investments on the condensed consolidated balance sheets.

(3)

Included as long-term investments on the condensed consolidated balance sheets.

As of June 30, 2021, there were no financial liabilities measured at fair value on a recurring basis.


			Fair value measurements as of December 31, 2020 using
			Quoted prices in		Significant		Significant
			active markets		other		unobservable
	December 31,		for identical		observable		inputs
	2020		assets (level 1)		inputs (level 2)		(level 3)
Assets:
Money market funds(1)	$	57,238	$	57,238	$	—	$	—
Commercial paper(1)		900		—		900		—
US treasury securities(2)		38,492		38,492		—		—
Corporate debt securities(2)		3,793		—		3,793		—
Commercial paper(2)		11,040		—		11,040		—
Total fair value of assets	$	111,463	$	95,730	$	15,733	$	—
Liabilities:
Preferred stock purchase right liability		1,615		—		—		1,615
Total fair value of liabilities	$	1,615	$	—	$	—	$	1,615

(1)

Included as cash and cash equivalents on the consolidated balance sheets.

(2)

Included as short-term investments on the consolidated balance sheets.

Summary of Assumptions Used to Determine Fair Value of Preferred Stock Purchase Right Liability

The assumptions used in the

Black-Scholes option pricing model to determine the fair value of the preferred stock purchase right liability at settlement date and December 31, 2020 were as follows:


	Settlement Date			December 31, 2020
Fair value of underlying preferred stock	$	6.11		$	6.11
Risk-free interest rate		0.07	%		0.08	%
Expected volatility		74.4	%		71.8	%
Expected term (in years)		0.00			0.08
Expected dividend yield		—	%		—	%

Investments (Tables)

6 Months Ended

Jun. 30, 2021

Investments Debt And Equity Securities [Abstract]

Summary of Investments Accounted for Available-for-Sale-Securities

The following tables summarize the Company’s investments accounted for as available-for-sale securities (in thousands, except years):


	June 30, 2021
	Maturity	Amortized		Unrealized			Unrealized		Estimated
	(in years)	cost		losses			gains		fair value
US treasury securities	1 or less	$	5,000	$	—		$	—	$	5,000
US government securities	1 or less		5,053		—			—		5,053
Corporate debt securities	1 or less		3,328		—			—		3,328
Commercial paper	1 or less		22,380		—			—		22,380
Supranational debt securities	1 or less		1,516		—			—		1,516
US government securities	1-2		5,001		(1	)		—		5,000
Total		$	42,278	$	(1	)	$	—	$	42,277


	December 31, 2020
	Maturity	Amortized		Unrealized			Unrealized		Estimated
	(in years)	cost		losses			gains		fair value
US treasury securities	1 or less	$	38,489	$	—		$	3	$	38,492
Corporate debt securities	1 or less		3,794		(1	)		—		3,793
Commercial paper	1 or less		11,040		—			—		11,040
Total		$	53,323	$	(1	)	$	3	$	53,325

Property and Equipment, Net (Tables)

6 Months Ended

Jun. 30, 2021

Property Plant And Equipment [Abstract]

Schedule of Property and Equipment, Net

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


	June 30,			December 31,
	2021			2020
Leasehold improvements	$	795		$	795
Laboratory equipment		2,083			1,380
Furniture and fixtures		168			165
Office equipment		61			61
Software		70			70
Computer equipment		299			278
Property and equipment		3,476			2,749
Less accumulated depreciation and amortization		(1,219	)		(902	)
Property and equipment, net	$	2,257		$	1,847

Accrued Expenses and Other Current Liabilities (Tables)

6 Months Ended

Jun. 30, 2021

Payables And Accruals [Abstract]

Schedule of Accrued Expenses and Other Current Liabilities

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


	June 30,		December 31,
	2021		2020
Accrued research and development expenses	$	6,307	$	6,649
Accrued compensation		3,069		2,416
Unvested early exercised stock option liability		3,230		2,526
Accrued offering costs		1,870	—
Accrued legal		468		194
Other accruals		575		140
Total	$	15,519	$	11,925

Stockholders' Deficit (Tables)

6 Months Ended

Jun. 30, 2021

Equity [Abstract]

Schedule of Convertible Preferred Stock

Convertible preferred stock consisted of the following (in thousands, except share data):


	June 30, 2021
	Preferred		Preferred shares						Common stock
	shares		issued and		Carrying		Liquidation		issuable upon
	authorized		outstanding		value		preference		conversion
Series A preferred stock		38,103,681		38,103,681	$	63,403	$	63,519		31,753,064
Series B-1 preferred stock		28,741,400		27,481,001		128,002		137,405		22,900,819
Series B-2 preferred stock		30,777,328		19,931,772		149,393		149,488		16,609,802
Total		97,622,409		85,516,454	$	340,798	$	350,412		71,263,685


	December 31, 2020
	Preferred		Preferred shares						Common stock
	shares		issued and		Carrying		Liquidation		issuable upon
	authorized		outstanding		value		preference		conversion
Series A preferred stock		38,103,681		38,103,681	$	63,403	$	63,519		31,753,064
Series B-1 preferred stock		28,741,400		27,481,001		128,002		137,405		22,900,819
Series B-2 preferred stock		30,777,328		4,000,000		30,000		30,000		3,333,333
Total		97,622,409		69,584,682	$	221,405	$	230,924		57,987,216

Stock-based Compensation (Tables)

6 Months Ended

Jun. 30, 2021

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Stock Option Activity

A summary of the Company’s stock option activity under the Plan is as follows (in thousands, except share and per share data and years):


						Weighted-
				Weighted-		average remaining		Aggregate
				average		contractual		intrinsic
	Shares			exercise price		term (years)		value
Outstanding at December 31, 2020		6,541,422		$	0.98		9.23	$	15,571
Granted		7,658,023			4.92
Exercised		(665,505	)		1.99				1,984
Canceled		(8,333	)		5.81
Outstanding at June 30, 2021		13,525,607		$	3.16		9.24	$	82,735
Options exercisable at June 30, 2021		1,902,188		$	1.97		8.87	$	13,903

Assumptions used to Determine Fair Value of Stock Option Grants

The assumptions used in the Black-Scholes option pricing model to determine the fair value of the employee and nonemployee stock option grants were as follows:


	Three months ended June 30,		Six months ended June 30,
	2021	2020(1)	2021	2020
Risk-free interest rate	1.02%-1.09%	--%	0.59%-1.09%	1.22%
Expected volatility	82.08%-82.54%	--%	82.08%-83.88%	74.72%
Expected term (in years)	6.08	0.00	6.08	6.25
Expected dividend yield	--%	--%	--%	--%

(1)

No stock options were granted during the three months ended June 30, 2020.

Summary of Restricted Stock Activity

The summary of the Company’s restricted stock activity during the six months ended June 30, 2021 is as follows:


	Number of			Weighted-
	restricted			average
	stock shares			grant date
	outstanding			fair Value
Nonvested at December 31, 2020		557,731		$	0.001
Vested		(172,394	)		0.001
Nonvested at June 30, 2021		385,337		$	0.001

Schedule of Stock-based Compensation Expense

The allocation of stock-based compensation for all stock awards was as follows (in thousands):


	Three months ended June 30,				Six months ended June 30,
	2021		2020		2021		2020
Research and development	$	925	$	52	$	1,416	$	101
General and administrative		711		57		1,015		113
Total	$	1,636	$	109	$	2,431	$	214

Summary of Common Stock Reserved for Future Issuance

Common stock reserved for future issuance consisted of the following as of June 30, 2021 and December 31, 2020:


	June 30,		December 31,
	2021		2020
Conversion of preferred stock outstanding		71,263,685		57,987,216
Conversion of preferred stock in future issuance (B-2)	—			10,979,319
Stock options issued and outstanding		13,525,607		6,541,422
Awards available for future grant		2,998,389		2,314,746
Total		87,787,681		77,822,703

Leases (Tables)

6 Months Ended

Jun. 30, 2021

Leases [Abstract]

Schedule of Future Minimum Lease Payments under Non-cancelable Operating Leases

Future minimum lease payments under non-cancelable operating leases with initial lease terms in excess of one year as of June 30, 2021 are as follows (in thousands):


Year ending December 31,
2021 (6 months remaining)	$	538
2022		969
2023		937
2024		401
Total lease payments	$	2,845
Less: Amount representing interest		(288	)
Operating lease liabilities	$	2,557

Net Loss Per Share (Tables)

6 Months Ended

Jun. 30, 2021

Earnings Per Share [Abstract]

Summary of Computation of Basic and Diluted Net Loss Per Share

The following table summarizes the computation of basic and diluted net loss per share of the Company (in thousands, except share and per share data):


	Three months ended June 30,						Six months ended June 30,
	2021			2020			2021			2020
Net loss	$	(28,214	)	$	(5,491	)	$	(46,231	)	$	(29,149	)
Weighted-average shares of common stock used in computing net loss per share, basic and diluted		23,546,390			20,834,976			22,893,533			20,733,283
Net loss per share, basic and diluted	$	(1.20	)	$	(0.26	)	$	(2.02	)	$	(1.41	)

Anti-dilutive Securities Excluded from Calculation of Diluted Net Loss Per Share


	Three months ended June 30,				Six months ended June 30,
	2021		2020		2021		2020
Convertible preferred stock issued		71,263,685		52,653,884		71,263,685		52,653,884
Conversion of convertible preferred stock in future issuance (B-2)	—			8,312,653	—			8,312,653
Options to purchase common stock		13,525,607		3,390,918		13,525,607		3,390,918
Restricted stock subject to future vesting		780,303		1,706,689		780,303		1,706,689
Options early exercised subject to future vesting		2,149,221		729,166		2,149,221		729,166
Total potentially dilutive shares		87,718,816		66,793,310		87,718,816		66,793,310

Organization and Basis of Presentation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	Jul. 20, 2021	Jul. 20, 2021	Jun. 30, 2021	Dec. 31, 2020
Organization And Basis Of Presentation [Line Items]
Cash, cash equivalents, and short-term investments			$ 193,700
Accumulated deficit			$ (161,633)	$ (115,402)
IPO \| Subsequent Event \| Common Stock
Organization And Basis Of Presentation [Line Items]
Net proceeds received from initial public offering (IPO)	$ 317,700	$ 317,700
Stock issued and sold		21,562,500
Price per share	$ 16.00	$ 16.00
Convertible preferred stock converted into shares of common stock		71,263,685
Underwriters Option to Purchase Additional Shares \| Subsequent Event \| Common Stock
Organization And Basis Of Presentation [Line Items]
Stock issued and sold		2,812,500

Summary of Significant Accounting Policies - Additional Information (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2021 USD ($) Segment	Jun. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Restricted cash	$ 408,000		$ 408,000		$ 312,000
Impairment losses	0	$ 0	0	$ 0
Deferred offering costs	$ 2,600,000		2,600,000		$ 0
Expected dividend yield			$ 0
Number of operating segment \| Segment			1
Number of reporting segment \| Segment			1
ASU 2018-13
Summary Of Significant Accounting Policies [Line Items]
Change in Accounting Principle, Accounting Standards Update, Adopted [true false]	true		true
Change in Accounting Principle, Accounting Standards Update, Adoption Date	Jan. 01, 2020		Jan. 01, 2020
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false]	true		true
ASU 2018-15
Summary Of Significant Accounting Policies [Line Items]
Change in Accounting Principle, Accounting Standards Update, Adopted [true false]	true		true
Change in Accounting Principle, Accounting Standards Update, Adoption Date	Jan. 01, 2021		Jan. 01, 2021
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false]	true		true
Minimum
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives of assets			3 years
Maximum
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives of assets			7 years

Summary of Significant Accounting Policies - Reconciliation of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020
Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	$ 156,396	$ 65,376	$ 104,339
Restricted cash	408
Total cash, cash equivalents and restricted cash as shown on the condensed consolidated statements of cash flows	$ 156,804		$ 104,339

Fair Value Measurements - Summary of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - Fair Value, Recurring - USD ($)
$ in Thousands

Jun. 30, 2021

Dec. 31, 2020

Assets:

Total fair value of assets

$ 192,461

$ 111,463

Liabilities:

Total fair value of liabilities

1,615

Preferred Stock Purchase Right Liability

Liabilities:

Total fair value of liabilities

1,615

Money Market Funds | Cash and Cash Equivalents

Assets:

Total fair value of assets

150,184

^[1]

57,238

^[2]

US Treasury Securities | Short-Term Investments

Assets:

Total fair value of assets

5,000

^[3]

38,492

^[4]

US Government Securities | Short-Term Investments

Assets:

Total fair value of assets

^[3]

5,053

US Government Securities | Long-Term Investments

Assets:

Total fair value of assets

^[5]

5,000

Corporate Debt Securities | Short-Term Investments

Assets:

Total fair value of assets

3,328

^[3]

3,793

^[4]

Commercial Paper | Cash and Cash Equivalents

Assets:

Total fair value of assets

^[2]

900

Commercial Paper | Short-Term Investments

Assets:

Total fair value of assets

22,380

^[3]

11,040

^[4]

Supranational Debt Securities | Short-Term Investments

Assets:

Total fair value of assets

^[3]

1,516

Quoted Prices in Active Markets for Identical Assets (Level 1)

Assets:

Total fair value of assets

155,184

95,730

Quoted Prices in Active Markets for Identical Assets (Level 1) | Money Market Funds | Cash and Cash Equivalents

Assets:

Total fair value of assets

150,184

^[1]

57,238

^[2]

Quoted Prices in Active Markets for Identical Assets (Level 1) | US Treasury Securities | Short-Term Investments

Assets:

Total fair value of assets

5,000

^[3]

38,492

^[4]

Significant Other Observable Inputs (Level 2)

Assets:

Total fair value of assets

37,277

15,733

Significant Other Observable Inputs (Level 2) | US Government Securities | Short-Term Investments

Assets:

Total fair value of assets

^[3]

5,053

Significant Other Observable Inputs (Level 2) | US Government Securities | Long-Term Investments

Assets:

Total fair value of assets

^[5]

5,000

Significant Other Observable Inputs (Level 2) | Corporate Debt Securities | Short-Term Investments

Assets:

Total fair value of assets

3,328

^[3]

3,793

^[4]

Significant Other Observable Inputs (Level 2) | Commercial Paper | Cash and Cash Equivalents

Assets:

Total fair value of assets

^[2]

900

Significant Other Observable Inputs (Level 2) | Commercial Paper | Short-Term Investments

Assets:

Total fair value of assets

22,380

^[3]

11,040

^[4]

Significant Other Observable Inputs (Level 2) | Supranational Debt Securities | Short-Term Investments

Assets:

Total fair value of assets

^[3]

$ 1,516

Significant Unobservable Inputs (Level 3)

Liabilities:

Total fair value of liabilities

1,615

Significant Unobservable Inputs (Level 3) | Preferred Stock Purchase Right Liability

Liabilities:

Total fair value of liabilities

$ 1,615

[1]	Included as cash and cash equivalents on the condensed consolidated balance sheets.
[2]	Included as cash and cash equivalents on the consolidated balance sheets.
[3]	Included as short-term investments on the condensed consolidated balance sheets.
[4]	Included as short-term investments on the consolidated balance sheets.
[5]	Included as long-term investments on the condensed consolidated balance sheets.

Fair Value Measurements - Additional Information (Details) - USD ($)	3 Months Ended	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Financial liabilities measured at fair value on recurring basis		$ 0
Measurement at fair value, transfers among Level 1, Level 2 or Level 3		0
Preferred Stock Purchase Right Liability
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Change in fair value of purchase right liability	$ 1,800,000	$ 1,600,000	$ 1,800,000

Fair Value Measurements - Summary of Assumptions Used to Determine Fair Value of Preferred Stock Purchase Right Liability (Details) - Black-Scholes Option Pricing Model - Preferred Stock Purchase Right Liability	6 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Fair Value of Underlying Preferred Stock
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Measurement input	0.0611	0.0611
Risk-free Interest Rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Measurement input	0.0007	0.0008
Expected Volatility
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Measurement input	0.744	0.718
Expected Term (in years)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Expected term (in years)	0 years	29 days
Expected Dividend Yield
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Measurement input	0	0

Investments - Summary of Investments Accounted for Available-for-Sale-Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities, Amortized cost	$ 42,278	$ 53,323
Available for sale securities, Unrealized losses	(1)	(1)
Available for sale securities, Unrealized gains		3
Available for sale securities, Estimated fair value	42,277	53,325
Short-Term Investments \| US Treasury Securities
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities, Amortized cost	5,000	38,489
Available for sale securities, Unrealized gains		3
Available for sale securities, Estimated fair value	$ 5,000	$ 38,492
Short-Term Investments \| US Treasury Securities \| Maximum
Schedule Of Available For Sale Securities [Line Items]
Maturity	1 year	1 year
Short-Term Investments \| US Government Securities
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities, Amortized cost	$ 5,053
Available for sale securities, Estimated fair value	$ 5,053
Short-Term Investments \| US Government Securities \| Maximum
Schedule Of Available For Sale Securities [Line Items]
Maturity	1 year
Short-Term Investments \| Corporate Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities, Amortized cost	$ 3,328	$ 3,794
Available for sale securities, Unrealized losses		(1)
Available for sale securities, Estimated fair value	$ 3,328	$ 3,793
Short-Term Investments \| Corporate Debt Securities \| Maximum
Schedule Of Available For Sale Securities [Line Items]
Maturity	1 year	1 year
Short-Term Investments \| Commercial Paper
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities, Amortized cost	$ 22,380	$ 11,040
Available for sale securities, Estimated fair value	$ 22,380	$ 11,040
Short-Term Investments \| Commercial Paper \| Maximum
Schedule Of Available For Sale Securities [Line Items]
Maturity	1 year	1 year
Short-Term Investments \| Supranational Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities, Amortized cost	$ 1,516
Available for sale securities, Estimated fair value	$ 1,516
Short-Term Investments \| Supranational Debt Securities \| Maximum
Schedule Of Available For Sale Securities [Line Items]
Maturity	1 year
Long-Term Investments \| US Government Securities
Schedule Of Available For Sale Securities [Line Items]
Available for sale securities, Amortized cost	$ 5,001
Available for sale securities, Unrealized losses	(1)
Available for sale securities, Estimated fair value	$ 5,000
Long-Term Investments \| US Government Securities \| Minimum
Schedule Of Available For Sale Securities [Line Items]
Maturity	1 year
Long-Term Investments \| US Government Securities \| Maximum
Schedule Of Available For Sale Securities [Line Items]
Maturity	2 years

Investments - Additional Information (Details) $ in Millions	Jun. 30, 2021 USD ($) Position	Dec. 31, 2020 USD ($) Position
Investments Debt And Equity Securities [Abstract]
Available of sale securities, unrealized loss position, Number of positions	2	6
Available for sale securities, gross unrealized loss position \| $	$ 6.5	$ 15.8
Available of sale securities, unrealized loss position, greater than 12 months, Number of positions	0

Property and Equipment, Net - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Property Plant And Equipment [Line Items]
Property and equipment	$ 3,476	$ 2,749
Less accumulated depreciation and amortization	(1,219)	(902)
Property and equipment, net	2,257	1,847
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment	795	795
Laboratory Equipment
Property Plant And Equipment [Line Items]
Property and equipment	2,083	1,380
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property and equipment	168	165
Office Equipment
Property Plant And Equipment [Line Items]
Property and equipment	61	61
Software
Property Plant And Equipment [Line Items]
Property and equipment	70	70
Computer Equipment
Property Plant And Equipment [Line Items]
Property and equipment	$ 299	$ 278

Property and Equipment, Net - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Property Plant And Equipment [Abstract]
Depreciation and amortization expense	$ 169,000	$ 134,000	$ 318,000	$ 255,000

Accrued Expenses and Other Current Liabilities - Schedule of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Payables And Accruals [Abstract]
Accrued research and development expenses	$ 6,307	$ 6,649
Accrued compensation	3,069	2,416
Unvested early exercised stock option liability	3,230	2,526
Accrued offering costs	1,870
Accrued legal	468	194
Other accruals	575	140
Total	$ 15,519	$ 11,925

Asset Acquisitions - Additional Information (Details) - USD ($)	1 Months Ended		3 Months Ended		6 Months Ended		12 Months Ended
	Mar. 31, 2021	Nov. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Asset Acquisitions [Line Items]
In-process research and development			$ 5,488,000		$ 9,168,000	$ 17,670,000
Asana Merger Agreement
Asset Acquisitions [Line Items]
Upfront payment made		$ 20,000,000.0
Future development and regulatory milestone cash payments maximum		$ 90,000,000.0
Additional shares required to issue upon achieving development milestone		3,888,889
In-process research and development			0	$ 0	0	$ 0	$ 50,000,000.0
Milestones accrued			0		0		$ 0
Asana Merger Agreement \| Series B-2 Convertible Preferred Stock
Asset Acquisitions [Line Items]
Shares issued		4,000,000
Value per share		$ 7.50
Total fair value		$ 30,000,000.0
ELS Purchase Agreement
Asset Acquisitions [Line Items]
Upfront payment made	$ 2,000,000.0
In-process research and development			$ 0		$ 3,700,000
ELS Purchase Agreement \| Common Stock
Asset Acquisitions [Line Items]
Shares issued	500,000
Value per share	$ 3.36
Total fair value	$ 1,700,000

License Agreements - Additional Information (Details) - USD ($)	1 Months Ended					3 Months Ended		6 Months Ended
	May 31, 2021	Jan. 31, 2021	Apr. 30, 2020	Mar. 31, 2020	Feb. 29, 2020	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
License Agreements [Line Items]
In-process research and development						$ 5,488,000		$ 9,168,000	$ 17,670,000
License Agreement \| NiKang Therapeutics, Inc.
License Agreements [Line Items]
Upfront payment					$ 5,000,000.0
Reimbursement of certain initial manufacturing costs					$ 400,000
Payment for US patent application			$ 7,000,000.0
Accrued development milestone payment						0		0		$ 4,000,000.0
In-process research and development						0	$ 0	0	12,000,000.0
Ownership percentage of equity or assets					50.00%
License Agreement \| NiKang Therapeutics, Inc. \| First Licensed Product \| Maximum
License Agreements [Line Items]
Development and regulatory milestone payments obligation					$ 16,000,000.0
Commercial milestone payments obligation					157,000,000.0
License Agreement \| NiKang Therapeutics, Inc. \| Second Licensed Product
License Agreements [Line Items]
Development and regulatory milestone payments obligation					12,000,000.0
Commercial milestone payments obligation					$ 151,000,000.0
License Agreement \| Katmai Pharmaceuticals, Inc.
License Agreements [Line Items]
Upfront payment				$ 5,700,000
In-process research and development						0	0	0	5,700,000
License Agreement \| Katmai Pharmaceuticals, Inc. \| Series B-1 Convertible Preferred Stock and Series B-2 Convertible Preferred Stock
License Agreements [Line Items]
Stock issued, value				2,700,000
License Agreement \| Katmai Pharmaceuticals, Inc. \| Series B-1 Convertible Preferred Stock
License Agreements [Line Items]
Stock issued, value			$ 1,800,000
Stock issued and sold			356,000
License Agreement \| Katmai Pharmaceuticals, Inc. \| Series B-2 Convertible Preferred Stock
License Agreements [Line Items]
Stock issued, value		$ 900,000
Stock issued and sold		118,666
License Agreement \| Katmai Pharmaceuticals, Inc. \| Maximum
License Agreements [Line Items]
Development and regulatory milestone payments obligation				26,000,000.0
Commercial milestone payments obligation				101,000,000.0
License Agreement \| LifeArc
License Agreements [Line Items]
Upfront payment				0
In-process research and development						0	0	0	0
One-time license payment				75,000
License Agreement \| LifeArc \| Maximum
License Agreements [Line Items]
Development and regulatory milestone payments obligation				11,000,000.0
Sales milestone payments obligation				$ 50,000,000.0
License Agreement \| The Regents
License Agreements [Line Items]
Upfront payment	$ 50,000
In-process research and development						$ 5,500,000	$ 0	$ 5,500,000	$ 0
Sales milestone payments obligation	$ 2,000,000.0
Percentage of third tier sublicensing fees	30.00%
License Agreement \| The Regents \| Common Stock
License Agreements [Line Items]
Stock issued and sold	944,945
License Agreement \| The Regents \| Maximum
License Agreements [Line Items]
Development and regulatory milestone payments obligation	$ 6,400,000

Stockholders' Deficit - Additional Information (Details) $ / shares in Units, $ in Thousands	1 Months Ended		3 Months Ended		6 Months Ended		12 Months Ended
	Jan. 31, 2021 USD ($) $ / shares shares	Apr. 30, 2020 USD ($) $ / shares shares	Jun. 30, 2021 USD ($) $ / shares shares	Jun. 30, 2020 shares	Jun. 30, 2021 USD ($) $ / shares shares	Jun. 30, 2020 USD ($) shares	Dec. 31, 2020 USD ($) $ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares	Feb. 28, 2021 shares	Apr. 15, 2020 $ / shares shares
Class of Stock [Line Items]
Common stock, shares authorized			156,000,000		156,000,000		147,027,681			156,000,000	147,027,681
Common stock, par value \| $ / shares			$ 0.0001		$ 0.0001		$ 0.0001				$ 0.0001
Convertible preferred stock, shares authorized			97,622,409		97,622,409
Convertible preferred stock, par value \| $ / shares			$ 0.0001		$ 0.0001
Proceeds from issuance of convertible preferred stock \| $					$ 119,393	$ 125,002
Preferred stock purchase right liability \| $							$ 1,615
Shares issued and sold			27,300,123		27,300,123		25,189,673
Common stock, shares outstanding			24,370,599		24,370,599		21,923,173
Fair value of common stock \| $ / shares			$ 9.28		$ 9.28		$ 3.36
Shares of common stock subject to repurchase			394,966		394,966		577,259
Number of shares vested			91,146	91,146	182,293	182,292
Common stock, voting rights					The restricted stock vests 25% one year from the vesting commencement date and monthly thereafter over a three-year period and is subject to repurchase by the Company in the event of any voluntary or involuntary termination of services to the Company prior to vesting.
Restricted Stock
Class of Stock [Line Items]
Shares issued									1,458,332
Share price per share \| $ / shares									$ 0.0001
Stock vesting period									3 years
Restricted Stock \| One Year from the Vesting Commencement Date and Monthly Thereafter Over Three-year Vesting Period
Class of Stock [Line Items]
Stock vesting percentage									25.00%
Series B Agreement
Class of Stock [Line Items]
Purchase agreement termination date		Sep. 30, 2022
Series B-1 convertible preferred shares converted into common stock		0.1
Series A Convertible Preferred Stock
Class of Stock [Line Items]
Convertible preferred stock, shares authorized			38,103,681		38,103,681		38,103,681
Convertible preferred stock, shares issued			38,103,681		38,103,681		38,103,681	10,150,000	27,953,681
Convertible preferred stock, issue price per share \| $ / shares								$ 1.667	$ 1.667
Proceeds from issuance of convertible preferred stock \| $								$ 16,900	$ 46,500
Series B-1 Convertible Preferred Stock
Class of Stock [Line Items]
Convertible preferred stock, shares authorized			28,741,400		28,741,400		28,741,400
Convertible preferred stock, shares issued			27,481,001		27,481,001		27,481,001
Series B-1 Convertible Preferred Stock \| Series B Agreement
Class of Stock [Line Items]
Convertible preferred stock, shares issued		27,481,001
Convertible preferred stock, issue price per share \| $ / shares		$ 5.00
Proceeds from issuance of convertible preferred stock \| $		$ 137,000
Series B-2 Convertible Preferred Stock
Class of Stock [Line Items]
Convertible preferred stock, shares authorized			30,777,328		30,777,328		30,777,328
Convertible preferred stock, shares issued			19,931,772		19,931,772		4,000,000
Convertible preferred stock, issue price per share \| $ / shares	$ 7.50						$ 7.50
Proceeds from issuance of convertible preferred stock \| $	$ 119,400
Preferred stock purchase right liability \| $			$ 9,000		$ 9,000
Gain (loss) for changes in fair value of convertible preferred stock purchase right liability \| $							$ 7,400
Convertible preferred stock, shares issued during period	13,175,191
Convertible preferred stock, additional shares issued	2,756,581
Convertible preferred stock shares issued in connection with asset acquisition							4,000,000
Series B-2 Convertible Preferred Stock \| Series B Agreement
Class of Stock [Line Items]
Convertible preferred stock, shares issued		13,175,191
Convertible preferred stock, issue price per share \| $ / shares		$ 7.50

Stockholders' Deficit - Schedule of Convertible Preferred Stock (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Temporary Equity [Line Items]
Preferred shares authorized	97,622,409
Common stock issuable upon conversion	87,787,681		77,822,703
Series A Convertible Preferred Stock
Temporary Equity [Line Items]
Preferred shares authorized	38,103,681		38,103,681
Preferred shares issued	38,103,681		38,103,681			10,150,000	27,953,681
Preferred shares outstanding	38,103,681		38,103,681
Carrying value	$ 63,403		$ 63,403
Liquidation preference	$ 63,519		$ 63,519
Common stock issuable upon conversion	31,753,064		31,753,064
Series B-1 Convertible Preferred Stock
Temporary Equity [Line Items]
Preferred shares authorized	28,741,400		28,741,400
Preferred shares issued	27,481,001		27,481,001
Preferred shares outstanding	27,481,001		27,481,001
Carrying value	$ 128,002		$ 128,002
Liquidation preference	$ 137,405		$ 137,405
Common stock issuable upon conversion	22,900,819		22,900,819
Series B-2 Convertible Preferred Stock
Temporary Equity [Line Items]
Preferred shares authorized	30,777,328		30,777,328
Preferred shares issued	19,931,772		4,000,000
Preferred shares outstanding	19,931,772		4,000,000
Carrying value	$ 149,393		$ 30,000
Liquidation preference	$ 149,488		$ 30,000
Common stock issuable upon conversion	16,609,802		3,333,333
Convertible Preferred Stock
Temporary Equity [Line Items]
Preferred shares authorized	97,622,409		97,622,409
Preferred shares issued	85,516,454		69,584,682
Preferred shares outstanding	85,516,454	85,516,454	69,584,682	63,184,682	38,103,681	38,103,681
Carrying value	$ 340,798	$ 340,798	$ 221,405	$ 181,050	$ 63,403	$ 63,403
Liquidation preference	$ 350,412		$ 230,924
Common stock issuable upon conversion	71,263,685		57,987,216

Stock-based Compensation - Additional Information (Details) - USD ($)	1 Months Ended		3 Months Ended		6 Months Ended		12 Months Ended
	Jan. 31, 2021	Jul. 31, 2018	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation, shares subject to repurchase			2,149,221		2,149,221		2,131,510
Share-based compensation, options granted that vest based on performance milestone				0
Stock-based compensation			$ 1,636,000	$ 109,000	$ 2,431,000	$ 214,000
Accrued Expenses and Other Current Liabilities
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation, liabilities associated with shares issued with repurchase rights			$ 3,200,000		$ 3,200,000		$ 2,500,000
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average grant date fair value of options granted			$ 4.59	$ 0	$ 3.45	$ 0.45
Unrecognized compensation cost related to unvested stock option grants			$ 29,300,000		$ 29,300,000
Unrecognized compensation cost expected to be recognized as expense, period					3 years 8 months 4 days
Aggregate fair value of stock options vested			500,000	$ 100,000	$ 800,000	$ 100,000
Share-based compensation, options granted that vest based on performance milestone	250,000				7,658,023
Performance-based Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation			$ 22,000		$ 115,000		$ 0
Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock vesting period								3 years
Restricted stock granted			0	0	0	0		1,795,827
Weighted-average grant date fair value of restricted stock granted								$ 0
Share-based Compensation, common stock shares subject to forfeiture			385,337		385,337		557,731
Total unrecognized compensation related to unvested restricted stock awards granted			$ 0		$ 0
Restricted Stock \| One Year from the Vesting Commencement Date and Monthly Thereafter Over Three-year Vesting Period
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock vesting percentage								25.00%
Share-based compensation, vesting rights description					The Company granted 1,795,827 shares of its restricted stock in 2018, which vest 25% one year from the vesting commencement date and monthly thereafter over a three-year period.
Restricted Stock \| 25% One Year from Vesting Commencement Date
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock vesting period								1 year
Restricted Stock \| Monthly Thereafter Over Three-year Vesting Period
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock vesting period								3 years
2018 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation, plan expiration period		10 years
Shares of common stock, authorized for issuance			21,545,845		21,545,845		13,212,511
2018 Equity Incentive Plan \| Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock vesting period					4 years
2018 Equity Incentive Plan \| Stock Options \| Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation, options grant in period, term					5 years
2018 Equity Incentive Plan \| Stock Options \| Minimum \| At the Time Option is Granted
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of fair market value of common stock					100.00%
2018 Equity Incentive Plan \| Stock Options \| Minimum \| For Holders of More Than 10% of Company's Total Combined Voting Power of All Classes of Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of fair market value of common stock					110.00%
2018 Equity Incentive Plan \| Stock Options \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation, plan expiration period					10 years

Stock-based Compensation - Summary of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended	6 Months Ended	12 Months Ended
	Jan. 31, 2021	Jun. 30, 2020	Jun. 30, 2021	Dec. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares Granted		0
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares Outstanding at December 31, 2020	6,541,422		6,541,422
Shares Granted	250,000		7,658,023
Shares Exercised			(665,505)
Shares Canceled			(8,333)
Shares Outstanding at June 30, 2021			13,525,607	6,541,422
Shares Options exercisable at June 30, 2021			1,902,188
Weighted-average exercise price, Outstanding at December 31, 2020	$ 0.98		$ 0.98
Weighted-average exercise price, Granted			4.92
Weighted-average exercise price, Exercised			1.99
Weighted-average exercise price, Canceled			5.81
Weighted-average exercise price, Outstanding at June 30, 2021			3.16	$ 0.98
Weighted-average exercise price, Options exercisable at June 30, 2021			$ 1.97
Weighted-average remaining contractual term (years), Outstanding			9 years 2 months 26 days	9 years 2 months 23 days
Weighted-average remaining contractual term (years), Options exercisable at June 30, 2021			8 years 10 months 13 days
Aggregate intrinsic value, Outstanding at December 31, 2020	$ 15,571		$ 15,571
Aggregate intrinsic value, Exercised			1,984
Aggregate intrinsic value, Outstanding at June 30, 2021			82,735	$ 15,571
Aggregate intrinsic value, Options exercisable at June 30, 2021			$ 13,903

Stock-based Compensation - Assumptions used to Determine Fair Value of Stock Option Grants (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Risk-free interest rate		0.00%		1.22%
Risk-free interest rate, minimum	1.02%		0.59%
Risk-free interest rate, maximum	1.09%		1.09%
Expected volatility		0.00%		74.72%
Expected volatility, minimum	82.08%		82.08%
Expected volatility, maximum	82.54%		83.88%
Expected term (in years)	6 years 29 days	0 years	6 years 29 days	6 years 3 months
Expected dividend yield	0.00%	0.00%	0.00%	0.00%

Stock-based Compensation - Assumptions used to Determine Fair Value of Stock Option Grants (Parenthetical) (Details)	3 Months Ended
	Jun. 30, 2020 shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Shares Granted	0

Stock-based Compensation - Summary of Restricted Stock Activity (Details) - Restricted Stock	6 Months Ended
	Jun. 30, 2021 $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of restricted stock shares outstanding, Nonvested at December 31, 2020 \| shares	557,731
Number of restricted stock shares outstanding, Vested \| shares	(172,394)
Number of restricted stock shares outstanding, Nonvested at June 30, 2021 \| shares	385,337
Weighted average grant date fair value, Nonvested at December 31, 2020 \| $ / shares	$ 0.001
Weighted-average grant date fair value, Vested \| $ / shares	0.001
Weighted-average grant date fair value, Nonvested at June 30, 2021 \| $ / shares	$ 0.001

Stock-based Compensation - Schedule of Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	$ 1,636	$ 109	$ 2,431	$ 214
Research and Development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	925	52	1,416	101
General and Administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation	$ 711	$ 57	$ 1,015	$ 113

Stock-based Compensation - Summary of Common Stock Reserved for Future Issuance (Details) - shares	Jun. 30, 2021	Dec. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance	87,787,681	77,822,703
Convertible Preferred Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance	71,263,685	57,987,216
Conversion of Preferred Stock in Future Issuance (B-2)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance	0	10,979,319
Stock Options Issued and Outstanding
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance	13,525,607	6,541,422
Awards Available for Future Grant
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for future issuance	2,998,389	2,314,746

Leases - Additional Information (Details)	1 Months Ended		3 Months Ended		6 Months Ended
Leases - Additional Information (Details)	Mar. 31, 2021 USD ($) ft²	Sep. 30, 2020 USD ($) ft²	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2018 ft²
Lessee Lease Description [Line Items]
Operating leases cancelable expiration dates					2032
Operating leases Noncancelable expiration dates					2022
Operating lease cost			$ 380,000	$ 321,000	$ 742,000	$ 661,000
Variable lease costs			123,000	78,000	228,000	175,000
Short-term lease costs			$ 30,000	$ 22,000	59,000	41,000
Cash paid for operating leases					$ 535,000	$ 470,000
Operating lease, weighted-average remaining lease term			2 years 8 months 15 days		2 years 8 months 15 days		3 years 1 month 28 days
Operating lease, weighted-average discount rate			7.80%		7.80%		7.80%
Office space leases, in square feet \| ft²								16,153
Lease expiration date					May 31, 2024
Lease commencement date					2021-08
Operating lease initial term			10 years 6 months		10 years 6 months
Letter of credit provided to lessor			$ 408,000		$ 408,000		$ 312,000
Lessee operating lease not yet commenced commitment amount					$ 51,600,000
2020 Lease
Lessee Lease Description [Line Items]
Office space leases, in square feet \| ft²		59,407
Lease commencement date		2021-08
Operating lease initial term		10 years 6 months
Operating lease, lease payments to lessor		$ 39,500,000
Tenant improvement allowance		$ 13,400,000
Term for cancellation of lease		84 months
Notice period for cancellation of lease		12 months
Operating lease cancellation payment		$ 1,900,000
2020 Lease \| Letter of Credit
Lessee Lease Description [Line Items]
Letter of credit provided to lessor		$ 312,000
Line of credit facility, expiration date		Oct. 31, 2031
First Amendment to 2020 Lease
Lessee Lease Description [Line Items]
Office space leases, in square feet \| ft²	18,421
Operating lease, lease payments to lessor	$ 96,000
Tenant improvement allowance	$ 3,400,000
Term for cancellation of lease	84 months
Operating lease cancellation payment	$ 2,500,000
First Amendment to 2020 Lease \| Letter of Credit
Lessee Lease Description [Line Items]
Letter of credit provided to lessor	$ 408,000
California
Lessee Lease Description [Line Items]
Office space leases, in square feet \| ft²								11,000

Leases - Schedule of Future Minimum Lease Payments under Non-cancelable Operating Leases (Details) $ in Thousands	Jun. 30, 2021 USD ($)
Leases [Abstract]
2021 (6 months remaining)	$ 538
2022	969
2023	937
2024	401
Total lease payments	2,845
Less: Amount representing interest	(288)
Operating lease liabilities	$ 2,557

Commitments and Contingencies - Additional Information (Details) - Litigation	6 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Commitments And Contingencies Disclosure [Abstract]
Number of litigations filed	0	0

Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Income Taxes [Line Items]
Provision for federal income taxes	$ 0	$ 0	$ 0	$ 0
Provision for state income taxes	0	0	0	0
Provision for foreign income taxes	0	0	0	0
Interest or penalties related to income taxes	$ 0	$ 0	$ 0	$ 0

Net Loss Per Share - Summary of Computation of Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
Earnings Per Share [Abstract]
Net loss	$ (28,214)	$ (18,017)	$ (5,491)	$ (23,658)	$ (46,231)	$ (29,149)
Weighted-average shares of common stock used in computing net loss per share, basic and diluted	23,546,390		20,834,976		22,893,533	20,733,283
Net loss per share, basic and diluted	$ (1.20)		$ (0.26)		$ (2.02)	$ (1.41)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

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+ Details

Net Loss Per Share - Anti-dilutive Securities Excluded from Calculation of Diluted Net Loss Per Share (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation of diluted net loss per share	87,718,816	66,793,310	87,718,816	66,793,310
Conversion of convertible preferred stock in future issuance (B-2)
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation of diluted net loss per share		8,312,653		8,312,653
Options to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation of diluted net loss per share	13,525,607	3,390,918	13,525,607	3,390,918
Restricted Stock Subject to Future Vesting
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation of diluted net loss per share	780,303	1,706,689	780,303	1,706,689
Options Early Exercised Subject to Future Vesting
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation of diluted net loss per share	2,149,221	729,166	2,149,221	729,166
Convertible Preferred Stock Issued
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from calculation of diluted net loss per share	71,263,685	52,653,884	71,263,685	52,653,884

Retirement Plan - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Compensation And Retirement Disclosure [Abstract]
Safe harbor contribution percentage			3.00%
Safe harbor contribution expense	$ 105,000	$ 0	$ 232,000	$ 0

Subsequent Events - Additional Information (Details) $ / shares in Units, $ in Millions				1 Months Ended
	Jul. 20, 2021 USD ($) $ / shares shares	Jul. 20, 2021 USD ($) $ / shares shares	Jul. 09, 2021	Aug. 31, 2021 USD ($)	Jul. 31, 2021 shares	May 31, 2021 shares	Jun. 30, 2021 shares	Feb. 28, 2021 shares	Dec. 31, 2020 shares	Apr. 15, 2020 shares
Subsequent Event [Line Items]
Common stock, shares authorized							156,000,000	156,000,000	147,027,681	147,027,681
Common stock reserved for future issuance							87,787,681		77,822,703
The Regents \| License Agreement \| Scenario Forecast
Subsequent Event [Line Items]
Cash payments in license agreement upon achievement of corporate milestone \| $				$ 1.7
IPO
Subsequent Event [Line Items]
Common stock, shares authorized							156,000,000
Common Stock \| The Regents \| License Agreement
Subsequent Event [Line Items]
Stock issued						944,945
Subsequent Event
Subsequent Event [Line Items]
Reverse stock split ratio			0.01
Reverse stock split, description			On July 9, 2021, the Company effected a one-for-1.2 reverse stock split of its issued and outstanding shares of common stock and a proportional adjustment to the existing conversion ratios for each series of the Company’s Preferred Stock.
Subsequent Event \| IPO
Subsequent Event [Line Items]
Undesignated preferred stock authorized	80,000,000	80,000,000
Undesignated preferred stock par value \| $ / shares	$ 0.0001	$ 0.0001
Common stock, shares authorized	800,000,000	800,000,000
Subsequent Event \| 2021 Incentive Award Plan
Subsequent Event [Line Items]
Common stock reserved for future issuance					15,150,000
Percentage of outstanding common stock maximum					5.00%
Subsequent Event \| ESPP
Subsequent Event [Line Items]
Common stock reserved for future issuance					1,260,000
Subsequent Event \| ESPP \| Minimum
Subsequent Event [Line Items]
Purchase price of common stock percent					85.00%
Subsequent Event \| Common Stock \| IPO
Subsequent Event [Line Items]
Stock issued	21,562,500
Shares issue, price per share \| $ / shares	$ 16.00	$ 16.00
Net proceeds received from initial public offering (IPO) \| $	$ 317.7	$ 317.7
Shares issued upon conversion of preferred stock	71,263,685	71,263,685
Subsequent Event \| Common Stock \| Underwriters Option to Purchase Additional Shares
Subsequent Event [Line Items]
Stock issued	2,812,500
Subsequent Event \| Erasca Foundation \| Common Stock
Subsequent Event [Line Items]
Stock issued					1,093,557