0001564590-21-056273 | 10-Q | XBRL Viewer | Sensei Biotherapeutics INC

Print Document View Excel Document

Document and Entity Information - shares	9 Months Ended
Document and Entity Information - shares	Sep. 30, 2021	Nov. 05, 2021
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Entity Registrant Name	Sensei Biotherapeutics, Inc.
Entity Central Index Key	0001829802
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		30,596,828
Entity Shell Company	false
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Title of 12(b) Security	Common Stock, $0.0001 par value per share
Trading Symbol	SNSE
Security Exchange Name	NASDAQ
Entity File Number	001-39980
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	83-1863385
Entity Address, Address Line One	1405 Research Blvd
Entity Address, Address Line Two	Suite 125
Entity Address, City or Town	Rockville
Entity Address, State or Province	MD
Entity Address, Postal Zip Code	20850
City Area Code	240
Local Phone Number	243-8000
Document Quarterly Report	true
Document Transition Report	false

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 9,533	$ 16,596
Marketable securities	147,129
Deferred offering costs		2,105
Prepaid expenses	1,199	1,375
Other current assets	301
Total current assets	158,162	20,076
Property and equipment, net	3,060	1,266
Deposits	27	86
Total assets	161,249	21,428
Current liabilities:
Accounts payable and accrued liabilities	3,614	3,882
Other liabilities	1,650	948
Total current liabilities	5,264	4,830
Debt		567
Other non-current liabilities	777	138
Total liabilities	6,041	5,535
Commitments and contingencies (Note 8)
Stockholders’ equity (deficit):
Common stock, $0.0001 par value; 1,230,000,000 shares authorized as of September 30, 2021, 30,588,495 shares and 1,875,422 shares issued and outstanding at September 30, 2021 and December 31, 2020, respectively	3
Additional paid-in capital	295,114	55,969
Accumulated deficit	(139,840)	(112,412)
Accumulated other comprehensive loss	(69)
Total stockholders’ equity (deficit)	155,208	(56,443)
Total liabilities, convertible preferred stock and stockholders’ equity (deficit)	$ 161,249	21,428
Convertible Preferred Stock Series AA
Temporary Equity
Convertible preferred stock		61,411
Convertible Preferred Stock Series BB
Temporary Equity
Convertible preferred stock		$ 10,925

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) - $ / shares	Sep. 30, 2021	Dec. 31, 2020
Statement Of Financial Position [Abstract]
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	1,230,000,000	1,230,000,000
Common stock, shares issued	30,588,495	1,875,422
Common stock, shares outstanding	30,588,495	1,875,422

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Operating expenses:
Research and development	$ 6,443	$ 3,576	$ 15,706	$ 8,629
General and administrative	3,873	1,788	12,363	5,007
Alvaxa IPR&D				738
Total operating expenses	10,316	5,364	28,069	14,374
Loss from operations	(10,316)	(5,364)	(28,069)	(14,374)
Other income (expense):
Interest income	278		466
Interest expense, including $0 and $645 with related parties in the three months and nine months ended September 30, 2021 and 2020, respectively	(214)	(3)	(364)	(1,635)
Fair value adjustments on embedded debt derivatives, including $0 and $575 with related parties in the three months and nine months ended September 30, 2021 and 2020, respectively				995
Loss on fixed asset disposition			(28)
Gain on debt extinguishment	567		567	45
Net loss	(9,685)	(5,367)	(27,428)	(14,969)
Cumulative dividends on convertible preferred stock				(104)
Net loss attributable to common stockholders	$ (9,685)	$ (5,367)	$ (27,428)	$ (15,073)
Net loss per common share, basic and diluted	$ (0.32)	$ (3.00)	$ (1.03)	$ (9.82)
Weighted-average number of shares used in computing net loss per common share, basic and diluted	30,588,495	1,787,124	26,736,745	1,535,033
Comprehensive loss:
Net loss	$ (9,685)	$ (5,367)	$ (27,428)	$ (14,969)
Other comprehensive items:
Unrealized gain (loss) on marketable securities	32		(69)
Total other comprehensive gain (loss)	32		(69)
Total comprehensive loss	$ (9,653)	$ (5,367)	$ (27,497)	$ (14,969)

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Statement [Abstract]
Interest expense, related party	$ 0	$ 645	$ 0	$ 645
Fair value adjustments on embedded debt derivative with related parties	$ 0	$ 575	$ 0	$ 575

CONDENSED CONSOLIDATED STATEMENTS OF CONVERTIBLE PREFERRED STOCK, COMMON STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) (Unaudited) - USD ($) $ in Thousands	Total	Convertible Preferred Stock (Series A-F)	Convertible Preferred Stock Series AA	Convertible Preferred Stock Series BB	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Beginning balance at Dec. 31, 2019	$ (68,662)					$ 23,650	$ (92,312)
Temporary equity, Beginning balance, shares at Dec. 31, 2019		15,257,663
Temporary equity, Beginning balance at Dec. 31, 2019		$ 47,545
Beginning balance, shares at Dec. 31, 2019					369,491
Stock-based compensation expense	194					194
Conversion of preferred stock into common stock	47,545					47,545
Temporary equity, Conversion of preferred stock into common stock, shares		(15,257,663)
Temporary equity, Conversion of preferred stock into common stock		$ (47,545)
Conversion of preferred stock into common stock, shares					627,871
Conversion of common stock into series AA preferred stock	(17,274)					(17,274)
Temporary equity, Conversion of common stock into series AA preferred stock			210,310,025
Temporary equity, Conversion of common stock into series AA preferred stock, shares			$ 17,274
Conversion of common stock into series AA preferred stock, shares					(148,732)
Preferred stock issued in exchange for note redemption			$ 15,456
Preferred stock issued in exchange for note redemption, shares			188,173,050
Issuance of preferred stock			$ 10,567
Issuance of preferred stock, shares			128,655,262
Issuance of common stock warrants, shares					634,118
Net loss	(4,692)						(4,692)
Ending balance at Mar. 31, 2020	(42,889)					54,115	(97,004)
Temporary equity, Ending balance, shares at Mar. 31, 2020			527,138,337
Temporary equity, Ending balance at Mar. 31, 2020			$ 43,297
Ending balance, shares at Mar. 31, 2020					1,482,748
Beginning balance at Dec. 31, 2019	(68,662)					23,650	(92,312)
Temporary equity, Beginning balance, shares at Dec. 31, 2019		15,257,663
Temporary equity, Beginning balance at Dec. 31, 2019		$ 47,545
Beginning balance, shares at Dec. 31, 2019					369,491
Net loss	(14,969)
Ending balance at Sep. 30, 2020	(51,681)					55,600	(107,281)
Temporary equity, Ending balance, shares at Sep. 30, 2020			630,592,111
Temporary equity, Ending balance at Sep. 30, 2020			$ 51,788
Ending balance, shares at Sep. 30, 2020					1,787,124
Beginning balance at Mar. 31, 2020	(42,889)					54,115	(97,004)
Temporary equity, Beginning balance, shares at Mar. 31, 2020			527,138,337
Temporary equity, Beginning balance at Mar. 31, 2020			$ 43,297
Beginning balance, shares at Mar. 31, 2020					1,482,748
Stock-based compensation expense	163					163
Issuance of common stock related to Alvaxa acquisition	541					541
Issuance of common stock related to Alvaxa acquisition, shares					304,376
Net loss	(4,910)						(4,910)
Ending balance at Jun. 30, 2020	(47,095)					54,819	(101,914)
Temporary equity, Ending balance, shares at Jun. 30, 2020			527,138,337
Temporary equity, Ending balance at Jun. 30, 2020			$ 43,297
Ending balance, shares at Jun. 30, 2020					1,787,124
Stock-based compensation expense	781					781
Issuance of preferred stock			$ 8,491
Issuance of preferred stock, shares			103,453,774
Net loss	(5,367)						(5,367)
Ending balance at Sep. 30, 2020	(51,681)					55,600	(107,281)
Temporary equity, Ending balance, shares at Sep. 30, 2020			630,592,111
Temporary equity, Ending balance at Sep. 30, 2020			$ 51,788
Ending balance, shares at Sep. 30, 2020					1,787,124
Beginning balance at Dec. 31, 2020	(56,443)					55,969	(112,412)
Temporary equity, Beginning balance, shares at Dec. 31, 2020			747,683,172	52,680,306
Temporary equity, Beginning balance at Dec. 31, 2020			$ 61,411	$ 10,925
Beginning balance, shares at Dec. 31, 2020					1,875,422
Stock-based compensation expense	1,349					1,349
Conversion of preferred stock into common stock	95,828				$ 2	95,826
Temporary equity, Conversion of preferred stock into common stock, shares			(747,683,172)	(165,956,208)
Temporary equity, Conversion of preferred stock into common stock			$ (61,411)	$ (34,416)
Conversion of preferred stock into common stock, shares					19,034,069
Issuance of preferred stock				$ 23,491
Issuance of preferred stock, shares				113,275,902
Issuance of common stock, net of issuance costs	138,489				$ 1	138,488
Issuance of common stock, net of issuance costs, shares					8,030,295
Issuance of common stock warrants	1					1
Issuance of common stock warrants, shares					1,648,709
Net loss	(7,972)						(7,972)
Ending balance at Mar. 31, 2021	171,252				$ 3	291,633	(120,384)
Ending balance, shares at Mar. 31, 2021					30,588,495
Beginning balance at Dec. 31, 2020	(56,443)					55,969	(112,412)
Temporary equity, Beginning balance, shares at Dec. 31, 2020			747,683,172	52,680,306
Temporary equity, Beginning balance at Dec. 31, 2020			$ 61,411	$ 10,925
Beginning balance, shares at Dec. 31, 2020					1,875,422
Unrealized gain (loss) on marketable securities	(69)
Net loss	(27,428)
Ending balance at Sep. 30, 2021	155,208				$ 3	295,114	(139,840)	$ (69)
Ending balance, shares at Sep. 30, 2021					30,588,495
Beginning balance at Mar. 31, 2021	171,252				$ 3	291,633	(120,384)
Beginning balance, shares at Mar. 31, 2021					30,588,495
Stock-based compensation expense	1,745					1,745
Unrealized gain (loss) on marketable securities	(101)							(101)
Net loss	(9,771)						(9,771)
Ending balance at Jun. 30, 2021	163,125				$ 3	293,379	(130,155)	(101)
Ending balance, shares at Jun. 30, 2021					30,588,495
Stock-based compensation expense	1,736					1,735
Unrealized gain (loss) on marketable securities	32							32
Net loss	(9,685)						(9,685)
Ending balance at Sep. 30, 2021	$ 155,208				$ 3	$ 295,114	$ (139,840)	$ (69)
Ending balance, shares at Sep. 30, 2021					30,588,495

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Operating activities
Net loss	$ (27,428)	$ (14,969)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	4,831	1,138
Depreciation and amortization	356	139
Accretion on debt		1,578
Accretion on marketable securities	359
Fair value adjustments on embedded debt derivatives		(995)
Interest on capital lease	6	8
Issuance of common stock for Alvaxa acquisition		541
Loss on fixed asset disposition	28
Gain on debt extinguishment	(567)	(45)
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(125)	(445)
Deposits	59	411
Accounts payable and accrued liabilities	(408)	(2,477)
Accrued interest		50
Other liabilities	498	41
Net cash used in operating activities	(22,391)	(15,025)
Investing activities
Purchases of property and equipment	(1,491)	(890)
Capital proceeds relating to property and equipment	293
Insurance proceeds relating to property and equipment	25
Purchases of short-term investments	(173,816)
Maturities and sales of short-term investments	26,259
Alvaxa IPR&D acquisition		(197)
Net cash used in investing activities	(148,730)	(1,087)
Financing activities
Proceeds from the PPP loan		567
Proceeds from the exercise of common stock warrants and options	1
Capital lease payments	(28)	(31)
Proceeds from issuance of common stock upon initial public offering, net of issuance costs	140,594
Net cash provided by financing activities	164,058	19,594
Net (decrease) increase in cash and cash equivalents	(7,063)	3,482
Cash and cash equivalents at beginning of period	16,596	251
Cash and cash equivalents at end of period	9,533	3,733
Supplemental disclosure of noncash financing and investing information:
Property and equipment additions included in accounts payable and accrued liabilities	103
Issuance costs included in accounts payable and accrued liabilities	534
Interest on financing	6	8
Convertible preferred stock issued in exchange for note redemption		15,456
Conversion of Series A, B, C, D, E, F Convertible Preferred Stock into Common Stock
Supplemental disclosure of noncash financing and investing information:
Conversion of stock		47,545
Conversion of Series AA and BB Convertible Preferred Stock into Common Stock
Supplemental disclosure of noncash financing and investing information:
Conversion of stock	95,826
Conversion of Common Stock into Series AA Convertible Preferred Stock
Supplemental disclosure of noncash financing and investing information:
Conversion of stock		17,274
Series AA Convertible Preferred Stock
Financing activities
Proceeds on the issuance of convertible preferred stock		$ 19,058
Series BB Convertible Preferred Stock
Financing activities
Proceeds on the issuance of convertible preferred stock	$ 23,491

Organization and Operations

9 Months Ended

Sep. 30, 2021

Organization Consolidation And Presentation Of Financial Statements [Abstract]

ORGANIZATION AND OPERATIONS

1. ORGANIZATION AND OPERATIONS

Business

Sensei Biotherapeutics, Inc. (the “Company” or “Sensei”) is a biopharmaceutical company that was incorporated in 1999 as a Maryland corporation until incorporated in Delaware on December 1, 2017. The Company is engaged in the discovery development and delivery of next generation immunotherapies with an initial focus on treatments for cancer.

Liquidity and capital resources

Since its inception, the Company has devoted substantially all of its resources to advancing development of its portfolio of programs, establishing and protecting its intellectual property, conducting research and development activities, organizing and staffing the Company, business planning, raising capital and providing general and administrative support for these operations. The Company is subject to risks and uncertainties common to early-stage companies in the biotechnology industry including, but not limited to, technical risks associated with the successful research, development and manufacturing of product candidates, development by competitors of new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with government regulations and the ability to secure additional capital to fund operations. Current and future programs will require significant research and development efforts, including extensive preclinical and clinical testing and regulatory approval prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel and infrastructure. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales.

Since its inception, the Company has incurred substantial losses and had a net loss of $27.4 million for the nine months ended September 30, 2021. As of September 30, 2021, the Company had an accumulated deficit of $139.8 million. The Company expects to generate operating losses and negative operating cash flows for the foreseeable future.

In February 2021, the Company completed its initial public offering (“IPO”), in which the Company issued and sold 8,030,295 shares of its common stock at a public offering price of $19.00 per share, for aggregate gross proceeds of $152.6 million. The Company received $138.5 million in net proceeds after deducting underwriting discounts and estimated offering expenses payable by the Company.

The Company expects that its cash, cash equivalents and marketable securities, as of September 30, 2021 of $156.7 million will be sufficient to fund its operations for at least the next twelve months from the date of issuance of these financial statements. The Company will need additional financing to support its continuing operations and pursue its growth strategy. Until such time as the Company can generate significant revenue from product sales, if ever, it expects to finance its operations through a combination of equity offerings, debt financings, collaborations, strategic alliances and licensing arrangements. The Company may be unable to raise additional funds or enter into such other agreements when needed on favorable terms or at all. The inability to raise capital as and when needed would have a negative impact on the Company’s financial condition and its ability to pursue its business strategy. The Company will need to generate significant revenue to achieve profitability, and it may never do so.

Reverse stock split

On January 29, 2021, the Company effected a reverse stock split of the Company’s common stock on a 48-for-1 basis (the “Reverse Stock Split”). In connection with the Reverse Stock Split, the conversion ratio for the Company’s Series AA and Series BB convertible preferred stock was proportionately adjusted such that the common stock issuable upon conversion of such preferred stock was decreased in proportion to the Reverse Stock Split. Accordingly, all common stock share and per share amounts, as well as all preferred stock conversion ratios, for all periods presented in these financial statements have been retroactively adjusted, to reflect this reverse stock split and adjustment of the Series AA and BB convertible preferred stock conversion ratios.

Summary of Significant Accounting Policies

9 Months Ended

Sep. 30, 2021

Accounting Policies [Abstract]

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Basis of Presentation and Principles of Consolidation

The Company has prepared the accompanying condensed consolidated financial statements in conformity with generally accepted accounting principles in the United States (“US GAAP”). The condensed consolidated financial statements include those accounts of the Company and its subsidiaries after elimination of all intercompany accounts and transactions.

Unaudited interim financial information

The condensed consolidated financial statements of the Company included herein have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). Certain information and note disclosures normally included in financial statements prepared in accordance with US GAAP have been condensed or omitted from these condensed consolidated financial statements, as is permitted by such rules and regulations. Accordingly, these condensed consolidated financial statements should be read in conjunction with the financial statements and notes thereto included in the Company’s Annual Report on Form 10-K. The results for any interim period are not necessarily indicative of results for any future period.

Use of Estimates

The preparation of condensed consolidated financial statements in conformity with US GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements, and the reported amounts of expenses during the reporting periods presented. Estimates are used for, but are not limited to, depreciation of equipment, the Company’s enterprise value, fair value of financial instruments, the Company’s ability to continue as a going concern and contingencies. Actual results may differ from those estimates.

Cash and cash equivalents

The Company classifies deposits in banks, money market funds and cash invested temporarily in various instruments with maturities of three months or less at the time of purchase as cash and cash equivalents. At September 30, 2021, cash and cash equivalents included cash on deposit at commercial banks and a money market fund that invests in U.S. Government securities.

Marketable securities

Investments consist of marketable securities with original maturities greater than 90 days. The Company has classified its investments with maturities beyond one year as short-term, based on their highly liquid nature and because such marketable securities represent the investment of cash that is available for current operations. The Company considers its investment portfolio of marketable securities to be available-for-sale. Accordingly, these investments are recorded at fair value (level 2). Unrealized gains and losses are reported as the accumulated other comprehensive items in stockholders’ equity. Amortization and accretion of premiums and discounts are recorded in other income (expense). Realized gains or losses on debt securities are included in interest income or interest expense, respectively. If any adjustment to fair value reflects a decline in value of the investment, the Company considers all available evidence to evaluate the extent to which the decline is other than temporary and, if so, marks the investment to market on the Company’s statement of operations and comprehensive loss.

Recently Issued Accounting Standards Updates

In February 2016, the FASB issued Accounting Standards Updates (“ASU”) No. 2016-02, Leases (Topic 842), as amended, with guidance regarding the accounting for and disclosure of leases. The update requires lessees to recognize the liabilities related to all leases, including operating leases on the balance sheet. This update also requires lessees and lessors to disclose key information about their leasing transactions. This update is effective for entities other than public business entities, including emerging growth companies that elected to defer compliance with new or revised financial accounting standards until a company that is not an issuer is required to comply with such standards, for annual reporting periods beginning after December 15, 2021, and interim periods within annual periods beginning after December 15, 2022. Early adoption is permitted. The Company is currently assessing the impact of adopting ASU No. 2016-02 on the condensed consolidated financial statements and related disclosures.

In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820), Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement. This update removed the following disclosure requirements: (1) the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy; (2) the policy for timing of transfers between levels; and (3) the valuation processes for Level 3 fair value measurements. Additionally, this update added the following disclosure requirements: (1) the changes in unrealized gains and losses for the period included in other comprehensive income and loss for recurring Level 3 fair value measurements held at the end of the reporting period; (2) the range and weighted average of

significant unobservable inputs used to develop Level 3 fair value measurements. For certain unobservable inputs, an entity may disclose other quantitative information (such as the median or arithmetic average) in lieu of the weighted average if the entity determines that other quantitative information would be a more reasonable and rational method to reflect the distribution of unobservable inputs used to develop Level 3 fair value measurements. The Company adopted ASU No. 2018-13 on January 1, 2020 and it did not have a material effect on the condensed consolidated financial statements and related disclosures.

In December 2019, the FASB issued ASU No. 2019-12, Simplifying the Accounting for Income Taxes. ASU No. 2019-12 eliminates certain exceptions related to the approach for intra-period tax allocation, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. It also clarifies and simplifies other aspects of the accounting for income taxes. This update is effective for entities other than public business entities, including emerging growth companies that elected to defer compliance with new or revised financial accounting standards until a company that is not an issuer is required to comply with such standards, for annual reporting periods beginning after December 15, 2021, and interim periods within annual periods beginning after December 15, 2022. The Company adopted ASU No. 2019-12 on January 1, 2020 and it did not have a material effect on the condensed consolidated financial statements and related disclosures.

Marketable Securities

9 Months Ended

Sep. 30, 2021

Investments Debt And Equity Securities [Abstract]

MARKETABLE SECURITIES

3. MARKETABLE SECURITIES

Marketable securities consist of the following (in thousands):

	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Commercial paper	$	52,965	$	3	$	(4	)	$	52,964
Corporate bonds		87,233		14		(77	)		87,170
U.S. Government agencies		7,000		-		(5	)		6,995
Total	$	147,198	$	17	$	(86	)	$	147,129

As of September 30, 2021, all marketable securities held by the Company had remaining contractual maturities of one year or less, except for corporate bonds and U.S. government agencies securities with a fair value of $65.6 million that had maturities of one to three years.

As of September 30, 2021, the marketable securities in a loss position had a maturity of less than one year, except for corporate bonds and U.S. government agencies securities with a fair value of $51.1 million, that had maturities of one to three years.

As of September 30, 2021, $16 thousand and $53 thousand of unrealized losses are associated with marketable securities with contractual maturities of one year or less and more than one year, respectively.

There were no impairments of the Company’s assets measured and carried at fair value during the nine months ended September 30, 2021.

Property and Equipment, Net

9 Months Ended

Sep. 30, 2021

Property Plant And Equipment [Abstract]

PROPERTY AND EQUIPMENT, NET

4. PROPERTY AND EQUIPMENT, NET

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

	September 30, 2021			December 31, 2020
Research equipment	$	3,387		$	1,767
Office equipment and furniture		475			94
Leaseholder improvement		77			-
Total property and equipment		3,939			1,861
Less accumulated depreciation and amortization		(879	)		(595	)
Property and equipment, net	$	3,060		$	1,266

Depreciation and amortization expense for the three months ended September 30, 2021 and 2020 was $136 thousand and $64 thousand, respectively, and for the nine months ended September 30, 2021 and 2020 was $356 thousand and $139 thousand, respectively.

Other Current Liabilities

9 Months Ended

Sep. 30, 2021

Other Liabilities Disclosure [Abstract]

OTHER CURRENT LIABILITIES

5. Other current liabilities

Other current liabilities consist of the following (in thousands):

	September 30, 2021		December 31, 2020
Compensation and benefits	$	1,615	$	916
Other		35		32
Total other current liabilities	$	1,650	$	948

Debt

9 Months Ended

Sep. 30, 2021

Debt Disclosure [Abstract]

DEBT

6. Debt

In May 2020, the Company received $567 thousand in loan funding from the Paycheck Protection Program (“PPP”) pursuant to the Coronavirus Aid, Relief, and Economic Security Act, as amended by the Flexibility Act, and administered by the Small Business Administration. The unsecured loan (the “PPP Loan”) is with Silicon Valley Bank.

Under the terms of the PPP Loan, interest accrues on the outstanding principal at a rate of 1.0% per annum. On August 6, 2021, the Small Business Administration approved the forgiveness for the full amount of the PPP Loan, which included principal of $567 thousand, plus interest. The Company recognized a gain on debt extinguishment in the Other income (expense) on the Consolidated Statement of Operations for the three and nine months ended September 30, 2021.

- Definition

The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-URI http://asc.fasb.org/topic&trid=2208564

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1B
-Subparagraph (h)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1C
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495334-112611

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1I
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495371-112611

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1I
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495371-112611

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(c))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1B
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1C
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495334-112611

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1C
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495334-112611

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1E
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495348-112611

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1I
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495371-112611

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1B
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611

+ Details

Fair Value Measurements

9 Months Ended

Sep. 30, 2021

Fair Value Disclosures [Abstract]

FAIR VALUE MEASUREMENTS

7. FAIR VALUE MEASUREMENTS

The following tables present information about the Company’s financial assets and liabilities measured at fair value on a recurring basis and indicate the level of the fair value hierarchy used to determine such fair values (in thousands):

	Fair value measurements at September 30, 2021
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents
Money market funds	$	7,854	$	-	$	-	$	7,854
Investments:
Commercial paper		-		52,964		-		52,964
Corporate bonds		-		87,170		-		87,170
U.S. Government agencies		-		6,995		-		6,995
Total	$	7,854	$	147,129	$	-	$	154,983

When developing fair value estimates, the Company maximizes the use of observable inputs and minimizes the use of unobservable inputs. When available, the Company uses quoted market prices to measure fair value. The valuation technique used to measure fair value for the Company's Level 1 and Level 2 assets is a market approach, using prices and other relevant information generated by market transactions involving identical or comparable assets. If market prices are not available, the fair value measurement is based on models that use primarily market-based parameters including yield curves, volatilities, credit ratings and currency rates. In certain cases where market rate assumptions are not available, the Company is required to make judgments about assumptions market participants would use to estimate the fair value of a financial instrument.

The Company’s embedded debt derivatives during 2020 are measured at fair value using a probability-weighted discounted cash flow valuation methodology. The determination of the fair value of embedded debt derivatives includes inputs not observable in the market and as such, represents a Level 3 measurement. The methodology utilized requires inputs based on certain subjective assumptions, including probabilities of debt settlement scenarios and a discount rate. This approach results in the classification of these embedded debt derivatives as Level 3 of the fair value hierarchy.

The assumptions utilized to value the embedded debt derivatives during the nine months ended September 30, 2020 prior to the settlement of such instruments included the actual outcome of the underling debt host contract, whether it was settled on a qualified financing prior to the contractual maturity date or settlement at the contractual maturity date. For the nine months ended September 30, 2020, the Company recognized $1.0 million of income in the condensed consolidated statement of operations as other income—fair value adjustments on embedded debt derivatives. The fair value of the embedded debt derivate was zero as of September 30, 2020 .

The following table provides a reconciliation of embedded debt derivatives measured at fair value on a recurring basis using significant unobservable inputs (Level 3) (in thousands):

	Amount
Balance at December 31, 2019	$	3,920
Change in fair value		(995	)
Settlement		(2,925	)
Balance at September 30, 2020	$	—

There were no transfers among Level 1, Level 2 or Level 3 categories in the three or nine months ended September 30, 2021 or September 30, 2020.

- 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

Commitments and Contingencies

9 Months Ended

Sep. 30, 2021

Commitments And Contingencies Disclosure [Abstract]

COMMITMENTS AND CONTINGENCIES

8. COMMITMENTS AND CONTINGENCIES

Operating Lease

As of September 30, 2021, the Company leases office facilities and other equipment under operating leases, which expire at various dates through 2027. Lease expense for the three months ended September 30, 2021 and 2020 was $414 thousand and $295 thousand, respectively, and for the nine months ended September 30, 2021 and 2020 was $920 thousand and $995 thousand, respectively.

The following table presents the future annual minimum payments required under noncancellable operating leases at September 30, 2021 (in thousands):

Remainder of 2021	$	391
2022		1,585
2023		1,606
2024		1,641
2025		1,688
2026		1,415
2027		59
Total operating lease obligations	$	8,385

As of September 30, 2021, the Company has letters of credit agreements outstanding totaling $678 thousand as security for office facility operating leases.

Capital Lease

The Company leases research equipment under a capital finance lease. The capital lease asset is classified within property and equipment, net within the Company’s condensed consolidated balance sheets.

On June 11, 2021, the Company entered into a lease for various research equipment. The terms of the four-year lease specify a monthly payment of $13 thousand, with the option to purchase the equipment for fair market value, to be determined by the lessor, at the end of the lease.

On June 29, 2021, the Company entered into a sale-leaseback arrangement with a third-party company (the “Buyer-lessor”) related to specific equipment of the Company. The equipment was sold for $293 thousand and leased back over an initial term of four years. The monthly lease payments are $7 thousand until the equipment is repurchased or the lease is terminated. At the end of the initial term, the Company has the option to repurchase the equipment at fair market value, not to exceed 15% of the original equipment cost, or to renew the lease for an additional one- or two-year period at a mutually agreed upon rate.

The following table presents the future annual minimum payments under the capitalized lease, together with the present value of net minimum lease payments at September 30, 2021 (in thousands):

Remainder of 2021	$	94
2022		239
2023		239
2024		239
2025		139
Total capital lease obligations	$	950
Less amount representing interest		(52	)

Present value of minimum capital lease obligations	$	898

License Agreements

In the normal course of business, the Company enters into licensing agreements with various parties to obtain the right to make, use, and sell licensed products currently in development.

Litigation

The Company records estimated losses from loss contingencies, such as a loss arising from a litigation, when it determines that it is probable a liability has been incurred and the amount of loss can be reasonably estimated. Litigation is subject to many factors that are difficult to predict so that there can be no assurance, in the event of a material unfavorable result in one or more claims, the Company will not incur material costs.

During 2017, the Company became actively involved in a matter pending in the Ontario (Canada) Superior Court of Justice which names, among multiple other defendants, the Company and two former officers of the Company. The claims pending in this matter allege breach of contract by the Company and seek declaratory and other relief, including monetary damages from the Company, and the individual defendants, including the Company’s former officers. The claims by such plaintiffs were originally made in a lawsuit filed in Ontario during October 2011, but was not pursued by such plaintiffs in any material manner until 2017. The Company believes that there is no merit to the claims alleged against the Company and its former officers, including no alleged breach of contract by the Company, and intends to vigorously defend against the claims pertaining to the Company and its former officers. At the present stage of the suit, management believes the outcome in this matter is not likely to have any material impact on the Company’s results, cash flows, or financial position.

Coronavirus pandemic

On January 30, 2020, the World Health Organization (“WHO”) announced a global health emergency because of a new strain of coronavirus originating in Wuhan, China and the risks to the international community as the virus spreads globally beyond its point of origin. In March 2020, the WHO classified the COVID-19 outbreak as a pandemic, based on the rapid increase in exposure globally. The full impact of the COVID-19 pandemic continues to evolve as of the date of these financial statements. As such, it is uncertain as to the full magnitude that the pandemic will have on the Company’s financial condition, liquidity, and future results of operations. Management is actively monitoring the global situation on its financial condition, liquidity, operations, suppliers, industry, and workforce. Given the daily evolution of the COVID-19 pandemic and the global responses to curb its spread, the Company is not able to estimate the effects of the COVID-19 pandemic on its results of operations, financial condition, or liquidity. Although the Company cannot estimate the length or gravity of the impact of the COVID-19 pandemic at this time, if the pandemic continues, it may have a material adverse effect on the Company’s results of future operations, financial position, and liquidity during the remainder of 2021 and 2022.

Equity

9 Months Ended

Sep. 30, 2021

Equity [Abstract]

EQUITY

9. Equity

Each share of common stock entitles the holder to one vote on all matters submitted to a vote of the Company’s stockholders. Common stockholders are not entitled to receive dividends, unless declared by the board of directors.

Series BB Convertible Preferred Stock Issuance

In January 2021, the Company issued and sold 113,275,902 shares of Series BB convertible preferred stock at $0.207383 per share in exchange for $23.5 million in gross proceeds.

Initial Public Offering

In February 2021, the Company completed its IPO in which the Company issued and sold 8,030,295 shares of its common stock, including 1,030,243 shares pursuant to the partial exercise of the underwriters’ option to purchase additional shares, at a public offering price of $19.00 per share, for aggregate gross proceeds of $152.6 million. The Company received approximately $138.5 million in net proceeds after deducting underwriting discounts and estimated offering expenses payable by the Company.

Upon closing of the IPO on February 8, 2021, all of the Company’s outstanding preferred stock converted into an aggregate of 19,034,069 shares of common stock.

On February 8, 2021, in connection with the IPO, the Company filed an Amended and Restated Certificate of Incorporation (the “Amended Certificate”) with the Secretary of State of the State of Delaware. The Amended Certificate, among other things: (i) authorized 250,000,000 shares of common stock; (ii) eliminated all references to the previously existing series of preferred stock; and (iii) authorized 10,000,000 shares of undesignated preferred stock that may be issued from time to time by the Company’s board of directors in one or more series.

Common Stock Warrants

The following is a summary of the common stock warrant activity related to common stock warrants issued in conjunction with equity and debt fundraising events for the nine months ended September 30, 2021:

	Number of Common Stock Warrants			Weighted- Average Exercise Price			Weighted- Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2020		412,262		$	9.60			6.71	$	1,380
Granted		1,648,709		$	0.01
Exercised		(1,648,709	)	$	(0.01	)
Expired		—
Outstanding at September 30, 2021		412,262		$	9.60			5.96	$	2,561

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496158-112644

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496158-112644

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 14
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496171-112644

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 14
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496171-112644

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 18
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496189-112644

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496158-112644

Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-URI http://asc.fasb.org/topic&trid=2208762

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 18
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496189-112644

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (h)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496158-112644

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 14
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496171-112644

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 18
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496189-112644

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 16
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496180-112644

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=123467817&loc=SL123496158-112644

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(e)(1))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

+ Details

Stock-Based Compensation

9 Months Ended

Sep. 30, 2021

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

STOCK-BASED COMPENSATION

10. STOCK-BASED COMPENSATION

2018 Equity Incentive Plan

The Company’s 2018 Stock Incentive Plan (the “2018 Plan”), provided for the Company to grant qualified incentive options, nonqualified options, stock grants and other stock-based awards to employees and non-employees to purchase the Company’s common stock. Upon the effectiveness of the 2021 Plan (as defined below), no further issuances will be made under the 2018 Plan.

2021 Stock Option and Incentive Plan

The 2021 Equity Incentive Plan (the “2021 Plan”) was approved by the board of directors on January 27, 2021, and the Company’s stockholders on January 28, 2021 and became effective on the execution of the underwriting agreement related to the IPO. The 2021 Plan provides for the grant of incentive stock options to employees, including employees of any parent or subsidiary corporations, and for the grant of nonstatutory stock options, stock appreciation rights, restricted stock awards, restricted stock unit awards, performance awards and other forms of stock awards to employees, directors, and consultants, including employees and consultants of the Company’s affiliates. The number of shares initially reserved for issuance under the 2021 Plan was 5,000,000, which will automatically increase on January 1 of each calendar year, starting on January 1, 2022 through January 1, 2031, in an amount equal to 4.0% of the total number of shares of the Company’s capital stock outstanding on the last day of the calendar month before the date of each automatic increase, or a lesser number of shares determined by the board of directors.

2021 Employee Stock Purchase Plan

The 2021 Employee Stock Purchase Plan (the “2021 ESPP”) was approved by the Company’s board of directors on January 27, 2021 and became effective on the execution of the underwriting agreement related to the IPO. A total of 333,333 shares of common stock were initially reserved for this issuance under the 2021 ESPP, which will automatically increase on January 1 of each calendar

year, beginning on January 1, 2022 through January 1, 2031, by an amount equal to 1.0% of the total shares of common stock outstanding on December 31st of the preceding calendar year, or the Evergreen Measurement Date; provided, that the number of shares added to the share reserve will be reduced automatically to the extent necessary to avoid causing the share reserve to exceed a number of shares equal to 1.0% of the shares of common stock outstanding on the applicable Evergreen Measurement Date and the board of directors may act prior to the first day of any calendar year to provide that there will be no January 1 increase in the share reserve for such calendar year or that the increase in the share reserve for such calendar year will be a lesser number of shares of the Company’s common stock than would otherwise occur. The purchase price of the shares under the 2021 ESPP, in the absence of a contrary designation, will be 85% of the lower of the fair market value of our common stock on the first trading day of the offering period or on the purchase date. As of September 30, 2021, the Company had not issued any shares under the 2021 ESPP. As of September 30, 2021, 333,333 shares were available to be issued under the 2021 ESPP. The Company recognized no share-based compensation expense related to the ESPP through September 30, 2021.

Stock Options

During 2021, the Company granted options to purchase shares of common stock to employees, consultants, and nonexecutive directors pursuant to the 2018 Plan and 2021 Plan, respectively. The Company uses the Black-Scholes option-pricing model to estimate the fair value of the stock options on the grant dates at a weighted average fair value of $12.58. There were 1,388,736 options available for grant under the 2021 Plan at September 30, 2021.

The following is a summary of the stock option award activity during the nine months ended September 30, 2021:

	Number of Stock Options			Weighted- Average Exercise Price			Weighted- Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2020		1,947,123		$	5.70			9.56	$	10,284
Granted		1,620,159		$	16.51
Exercised		—		$	—
Forfeited		(303,082	)	$	(5.91	)
Expired		—		$	—
Outstanding at September 30, 2021		3,264,200		$	11.04			9.02	$	14,804
Exercisable at September 30, 2021		793,677		$	10.66			8.55	$	6,310
Options expected to vest as of September 30, 2021		2,470,523		$	11.16			9.23	$	8,494

The total fair value of options vested during the nine months ended September 30, 2021 was $2.5 million.

At September 30, 2021, there was approximately $19.7 million of unrecognized stock-based compensation expense associated with the stock options, which is expected to be recognized over a weighted-average period of 3.15 years.

Common Stock Warrants

The following is a summary of the employee-issued common stock warrant activity during the nine months ended September 30, 2021:

	Number of Common Stock Warrants		Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2020		57,212	$	7.62		3.64	$	98
Granted		—	$	—
Exercised		—	$	—
Expired		—	$	—
Outstanding and exercisable at September 30, 2021		57,212	$	7.62		2.89	$	269

As of September 30, 2021 there was no unrecognized stock-based compensation expense associated with the common stock warrants.

For the nine months ended September 30, 2021, the Company utilized the Black-Scholes option-pricing model for estimating the fair value of the stock options granted. The following table presents the assumptions and the Company’s methodology for developing each of the assumptions used:

	Nine Months Ended September 30,
	2021	2020
Volatility	89.31%-98.04%	90.0%
Expected life (years)	5.52-6.08	0.5-4.0
Risk-free interest rate	0.4%–1.2%	0.11%-0.18%
Dividend rate	—%	—%

•

Volatility—The Company estimates the expected volatility of its common stock at the date of grant based on the historical volatility of comparable public companies over the expected term.

•

Expected life—The expected life is estimated as the contractual term.

•

Risk-free interest rate—The risk-free rate for periods within the estimated life of the stock award is based on the U.S. Treasury yield curve in effect at the time of grant.

•

Dividend rate—The assumed dividend yield is based upon the Company’s expectation of not paying dividends in the foreseeable future.

Stock-based compensation expense was recorded in the following line items in the condensed consolidated statements of operations for the three and nine months ended September 30, 2021 and 2020 (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Research and development	$	691	$	340	$	1,839	$	441
General and administrative		1,045		441		2,991		697
Total stock-based compensation expense	$	1,736	$	781	$	4,830	$	1,138

Employee Retirement Plan

9 Months Ended

Sep. 30, 2021

Compensation And Retirement Disclosure [Abstract]

EMPLOYEE RETIREMENT PLAN

11. EMPLOYEE RETIREMENT PLAN

The Company maintains a defined contribution 401(k) profit-sharing plan (the “Plan”) for all employees. Under the Plan, participants may make voluntary contributions up to the maximum amount allowable by law. The Plan is based on employees’ salary deferral, and the Company matches employees’ contributions up to 4% of the employees’ base salary. Employees are 100% vested in the Company’s match contributions. During the three months ended September 30, 2021 and 2020, the Company accrued expense of $62 thousand and $26 thousand, respectively. During the nine months ended September 30, 2021 and 2020, the Company accrued expenses of $167 thousand and $78 thousand, respectively.

- Definition

The entire disclosure for retirement benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 55
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=123450688&loc=d3e4179-114921

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section S99
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=21916913&loc=d3e273930-122802

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(i)
-URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (o)
-URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (p)
-URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 70
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-URI http://asc.fasb.org/topic&trid=2235017

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 60
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6414203&loc=d3e39689-114964

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(iv)(03)
-URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (q)
-URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (r)(1)
-URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(iii)
-URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (l)
-URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (r)(2)
-URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920

+ Details

Related-Party Transactions

9 Months Ended

Sep. 30, 2021

RELATED-PARTY TRANSACTIONS

12. RELATED-PARTY TRANSACTIONS

Debt

During March 2020, a principal owner of the Company purchased the 2019 Special Note directly from the original holder.

Consulting Agreement

During 2020, the Company entered into an agreement with a principal owner of the Company to provide consulting services to the Company in exchange for $1,500 thousand. Under the terms of the agreement, the Company recorded expense of $1,125 thousand in 2020, with the $1,500 thousand payment made in January 2021. The contract was completed and the remaining balance of $375 thousand under the agreement was recorded as an expense in January 2021.

Income Taxes

9 Months Ended

Sep. 30, 2021

Income Tax Disclosure [Abstract]

INCOME TAXES

13. INCOME TAXES

The Company recorded no provision for income taxes for the three and nine months ended September 30, 2021 and 2020.

Deferred tax assets and deferred tax liabilities are recognized based on temporary differences between the financial reporting and tax bases of assets and liabilities using statutory rates. Management of the Company has evaluated the positive and negative evidence bearing upon the realizability of its deferred tax assets, which are comprised principally of net operating loss carryforwards and research and development credits. Under the applicable accounting standards, management has considered the Company’s history of losses and concluded that it is more likely than not that the Company will not recognize the benefits of federal and state deferred tax assets. Accordingly, a full valuation allowance has been established against the Company’s otherwise recognizable net deferred tax assets.

- 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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 21
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32857-109319

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 11.C)
-URI http://asc.fasb.org/extlink&oid=122134291&loc=d3e330215-122817

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 17
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32809-109319

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I.5.Q1)
-URI http://asc.fasb.org/extlink&oid=122134291&loc=d3e330036-122817

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32705-109319

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 270
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6424409&loc=d3e44925-109338

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-URI http://asc.fasb.org/topic&trid=2144680

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6424122&loc=d3e41874-109331

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(2))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

+ Details

Net Loss Per Share

9 Months Ended

Sep. 30, 2021

Earnings Per Share [Abstract]

NET LOSS PER SHARE

14. NET LOSS PER SHARE

Basic and diluted net loss per share attributable to common stockholders is calculated as follows (in thousands except share and per share amounts):

	Three Months Ended September 30,						Nine Months Ended September 30,
	2021			2020			2021			2020
Net loss	$	(9,685	)	$	(5,367	)	$	(27,428	)	$	(14,969	)
Cumulative dividends on convertible preferred stock		—			—			—			(104	)
Net loss attributable to common stockholders	$	(9,685	)	$	(5,367	)	$	(27,428	)	$	(15,073	)
Net loss per share—basic and diluted	$	(0.32	)	$	(3.00	)	$	(1.03	)	$	(9.82	)
Weighted-average number of shares used in computing net loss per share—basic and diluted		30,588,495			1,787,124			26,736,745			1,535,033

The following outstanding potentially dilutive securities have been excluded from the calculation of diluted net loss per share, as their effect is anti-dilutive:

	For the Three Months Ended September 30,				For the Nine Months Ended September 30,
	2021		2020		2021		2020
Convertible preferred stock		—		630,592,111		—		630,592,111
Stock options to purchase common stock		3,264,200		1,660,864		3,264,200		1,660,864
Warrants issued to employees and contractor to purchase common stock		57,212		57,420		57,212		57,420
Warrants issued related to convertible notes and other equity agreements		412,262		412,262		412,262		412,262

Summary of Significant Accounting Policies (Policies)	9 Months Ended
Summary of Significant Accounting Policies (Policies)	Sep. 30, 2021
Accounting Policies [Abstract]
Basis of Presentation and Principles of Consolidation	Basis of Presentation and Principles of Consolidation The Company has prepared the accompanying condensed consolidated financial statements in conformity with generally accepted accounting principles in the United States (“US GAAP”). The condensed consolidated financial statements include those accounts of the Company and its subsidiaries after elimination of all intercompany accounts and transactions.
Unaudited interim financial information	Unaudited interim financial information The condensed consolidated financial statements of the Company included herein have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). Certain information and note disclosures normally included in financial statements prepared in accordance with US GAAP have been condensed or omitted from these condensed consolidated financial statements, as is permitted by such rules and regulations. Accordingly, these condensed consolidated financial statements should be read in conjunction with the financial statements and notes thereto included in the Company’s Annual Report on Form 10-K. The results for any interim period are not necessarily indicative of results for any future period.
Use of Estimates	Use of Estimates The preparation of condensed consolidated financial statements in conformity with US GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements, and the reported amounts of expenses during the reporting periods presented. Estimates are used for, but are not limited to, depreciation of equipment, the Company’s enterprise value, fair value of financial instruments, the Company’s ability to continue as a going concern and contingencies. Actual results may differ from those estimates.
Cash and Cash Equivalents	Cash and cash equivalents The Company classifies deposits in banks, money market funds and cash invested temporarily in various instruments with maturities of three months or less at the time of purchase as cash and cash equivalents. At September 30, 2021, cash and cash equivalents included cash on deposit at commercial banks and a money market fund that invests in U.S. Government securities.
Marketable Securities	Marketable securities Investments consist of marketable securities with original maturities greater than 90 days. The Company has classified its investments with maturities beyond one year as short-term, based on their highly liquid nature and because such marketable securities represent the investment of cash that is available for current operations. The Company considers its investment portfolio of marketable securities to be available-for-sale. Accordingly, these investments are recorded at fair value (level 2). Unrealized gains and losses are reported as the accumulated other comprehensive items in stockholders’ equity. Amortization and accretion of premiums and discounts are recorded in other income (expense). Realized gains or losses on debt securities are included in interest income or interest expense, respectively. If any adjustment to fair value reflects a decline in value of the investment, the Company considers all available evidence to evaluate the extent to which the decline is other than temporary and, if so, marks the investment to market on the Company’s statement of operations and comprehensive loss.
Recently Issued Accounting Standards Updates	Recently Issued Accounting Standards Updates In February 2016, the FASB issued Accounting Standards Updates (“ASU”) No. 2016-02, Leases (Topic 842), as amended, with guidance regarding the accounting for and disclosure of leases. The update requires lessees to recognize the liabilities related to all leases, including operating leases on the balance sheet. This update also requires lessees and lessors to disclose key information about their leasing transactions. This update is effective for entities other than public business entities, including emerging growth companies that elected to defer compliance with new or revised financial accounting standards until a company that is not an issuer is required to comply with such standards, for annual reporting periods beginning after December 15, 2021, and interim periods within annual periods beginning after December 15, 2022. Early adoption is permitted. The Company is currently assessing the impact of adopting ASU No. 2016-02 on the condensed consolidated financial statements and related disclosures. In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820), Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement. This update removed the following disclosure requirements: (1) the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy; (2) the policy for timing of transfers between levels; and (3) the valuation processes for Level 3 fair value measurements. Additionally, this update added the following disclosure requirements: (1) the changes in unrealized gains and losses for the period included in other comprehensive income and loss for recurring Level 3 fair value measurements held at the end of the reporting period; (2) the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. For certain unobservable inputs, an entity may disclose other quantitative information (such as the median or arithmetic average) in lieu of the weighted average if the entity determines that other quantitative information would be a more reasonable and rational method to reflect the distribution of unobservable inputs used to develop Level 3 fair value measurements. The Company adopted ASU No. 2018-13 on January 1, 2020 and it did not have a material effect on the condensed consolidated financial statements and related disclosures. In December 2019, the FASB issued ASU No. 2019-12, Simplifying the Accounting for Income Taxes. ASU No. 2019-12 eliminates certain exceptions related to the approach for intra-period tax allocation, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. It also clarifies and simplifies other aspects of the accounting for income taxes. This update is effective for entities other than public business entities, including emerging growth companies that elected to defer compliance with new or revised financial accounting standards until a company that is not an issuer is required to comply with such standards, for annual reporting periods beginning after December 15, 2021, and interim periods within annual periods beginning after December 15, 2022. The Company adopted ASU No. 2019-12 on January 1, 2020 and it did not have a material effect on the condensed consolidated financial statements and related disclosures.

Marketable Securities (Tables)

9 Months Ended

Sep. 30, 2021

Investments Debt And Equity Securities [Abstract]

Summary of Marketable Securities

Marketable securities consist of the following (in thousands):

	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Commercial paper	$	52,965	$	3	$	(4	)	$	52,964
Corporate bonds		87,233		14		(77	)		87,170
U.S. Government agencies		7,000		-		(5	)		6,995
Total	$	147,198	$	17	$	(86	)	$	147,129

Property and Equipment, Net (Tables)

9 Months Ended

Sep. 30, 2021

Property Plant And Equipment [Abstract]

Summary of Property and Equipment, Net

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

	September 30, 2021			December 31, 2020
Research equipment	$	3,387		$	1,767
Office equipment and furniture		475			94
Leaseholder improvement		77			-
Total property and equipment		3,939			1,861
Less accumulated depreciation and amortization		(879	)		(595	)
Property and equipment, net	$	3,060		$	1,266

Other Current Liabilities (Tables)

9 Months Ended

Sep. 30, 2021

Other Liabilities Disclosure [Abstract]

Summary of Other Current Liabilities

Other current liabilities consist of the following (in thousands):

	September 30, 2021		December 31, 2020
Compensation and benefits	$	1,615	$	916
Other		35		32
Total other current liabilities	$	1,650	$	948

Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2021

Fair Value Disclosures [Abstract]

Schedule of Financial Assets And Liabilities Measured at Fair Value on Recurring Basis

	Fair value measurements at September 30, 2021
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents
Money market funds	$	7,854	$	-	$	-	$	7,854
Investments:
Commercial paper		-		52,964		-		52,964
Corporate bonds		-		87,170		-		87,170
U.S. Government agencies		-		6,995		-		6,995
Total	$	7,854	$	147,129	$	-	$	154,983

Schedule of Reconciliation of Embedded Debt Derivatives Measured Fair Value on Recurring Basis

The following table provides a reconciliation of embedded debt derivatives measured at fair value on a recurring basis using significant unobservable inputs (Level 3) (in thousands):

	Amount
Balance at December 31, 2019	$	3,920
Change in fair value		(995	)
Settlement		(2,925	)
Balance at September 30, 2020	$	—

Commitments and Contingencies (Tables)

9 Months Ended

Sep. 30, 2021

Commitments And Contingencies Disclosure [Abstract]

Schedule of Future Annual Minimum Payments Under Noncancellable Operating Lease

The following table presents the future annual minimum payments required under noncancellable operating leases at September 30, 2021 (in thousands):

Remainder of 2021	$	391
2022		1,585
2023		1,606
2024		1,641
2025		1,688
2026		1,415
2027		59
Total operating lease obligations	$	8,385

Schedule of Future Annual Minimum Payments Under Capitalized Lease

The following table presents the future annual minimum payments under the capitalized lease, together with the present value of net minimum lease payments at September 30, 2021 (in thousands):

Remainder of 2021	$	94
2022		239
2023		239
2024		239
2025		139
Total capital lease obligations	$	950
Less amount representing interest		(52	)

Present value of minimum capital lease obligations	$	898

Equity (Tables)

9 Months Ended

Sep. 30, 2021

Summary of Common Stock Warrant Activity

The following is a summary of the employee-issued common stock warrant activity during the nine months ended September 30, 2021:

	Number of Common Stock Warrants		Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2020		57,212	$	7.62		3.64	$	98
Granted		—	$	—
Exercised		—	$	—
Expired		—	$	—
Outstanding and exercisable at September 30, 2021		57,212	$	7.62		2.89	$	269

Warrant | Equity and Debt Fundraising Events

Summary of Common Stock Warrant Activity

	Number of Common Stock Warrants			Weighted- Average Exercise Price			Weighted- Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2020		412,262		$	9.60			6.71	$	1,380
Granted		1,648,709		$	0.01
Exercised		(1,648,709	)	$	(0.01	)
Expired		—
Outstanding at September 30, 2021		412,262		$	9.60			5.96	$	2,561

Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2021

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Stock Option Award Activity

The following is a summary of the stock option award activity during the nine months ended September 30, 2021:

	Number of Stock Options			Weighted- Average Exercise Price			Weighted- Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2020		1,947,123		$	5.70			9.56	$	10,284
Granted		1,620,159		$	16.51
Exercised		—		$	—
Forfeited		(303,082	)	$	(5.91	)
Expired		—		$	—
Outstanding at September 30, 2021		3,264,200		$	11.04			9.02	$	14,804
Exercisable at September 30, 2021		793,677		$	10.66			8.55	$	6,310
Options expected to vest as of September 30, 2021		2,470,523		$	11.16			9.23	$	8,494

Summary of Common Stock Warrant Activity

The following is a summary of the employee-issued common stock warrant activity during the nine months ended September 30, 2021:

	Number of Common Stock Warrants		Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2020		57,212	$	7.62		3.64	$	98
Granted		—	$	—
Exercised		—	$	—
Expired		—	$	—
Outstanding and exercisable at September 30, 2021		57,212	$	7.62		2.89	$	269

Summary of Fair Value Assumptions and Methodology

The following table presents the assumptions and the Company’s methodology for developing each of the assumptions used:

	Nine Months Ended September 30,
	2021	2020
Volatility	89.31%-98.04%	90.0%
Expected life (years)	5.52-6.08	0.5-4.0
Risk-free interest rate	0.4%–1.2%	0.11%-0.18%
Dividend rate	—%	—%

Summary of Stock-Based Compensation Expense

	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Research and development	$	691	$	340	$	1,839	$	441
General and administrative		1,045		441		2,991		697
Total stock-based compensation expense	$	1,736	$	781	$	4,830	$	1,138

Net Loss Per Share (Tables)

9 Months Ended

Sep. 30, 2021

Earnings Per Share [Abstract]

Schedule of Basic and Diluted Net Loss Per Share

Basic and diluted net loss per share attributable to common stockholders is calculated as follows (in thousands except share and per share amounts):

	Three Months Ended September 30,						Nine Months Ended September 30,
	2021			2020			2021			2020
Net loss	$	(9,685	)	$	(5,367	)	$	(27,428	)	$	(14,969	)
Cumulative dividends on convertible preferred stock		—			—			—			(104	)
Net loss attributable to common stockholders	$	(9,685	)	$	(5,367	)	$	(27,428	)	$	(15,073	)
Net loss per share—basic and diluted	$	(0.32	)	$	(3.00	)	$	(1.03	)	$	(9.82	)
Weighted-average number of shares used in computing net loss per share—basic and diluted		30,588,495			1,787,124			26,736,745			1,535,033

Potentially Dilutive Securities Excluded from Calculation of Diluted Net Loss Per Share

The following outstanding potentially dilutive securities have been excluded from the calculation of diluted net loss per share, as their effect is anti-dilutive:

	For the Three Months Ended September 30,				For the Nine Months Ended September 30,
	2021		2020		2021		2020
Convertible preferred stock		—		630,592,111		—		630,592,111
Stock options to purchase common stock		3,264,200		1,660,864		3,264,200		1,660,864
Warrants issued to employees and contractor to purchase common stock		57,212		57,420		57,212		57,420
Warrants issued related to convertible notes and other equity agreements		412,262		412,262		412,262		412,262

Organization and Operations - Additional Information (Details) $ / shares in Units, $ in Thousands		1 Months Ended	3 Months Ended						9 Months Ended
	Jan. 29, 2021	Feb. 28, 2021 USD ($) $ / shares shares	Sep. 30, 2021 USD ($)	Jun. 30, 2021 USD ($)	Mar. 31, 2021 USD ($) shares	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)
Subsidiary Sale Of Stock [Line Items]
Net loss			$ (9,685)	$ (9,771)	$ (7,972)	$ (5,367)	$ (4,910)	$ (4,692)	$ (27,428)	$ (14,969)
Accumulated deficit			(139,840)						(139,840)		$ (112,412)
Cash, cash equivalents and marketable securities			$ 156,700						$ 156,700
Reverse stock split description									On January 29, 2021, the Company effected a reverse stock split of the Company’s common stock on a 48-for-1 basis (the “Reverse Stock Split”).
Reverse stock split conversion ratio	0.020833
Common Stock
Subsidiary Sale Of Stock [Line Items]
Common stock shares issued and sold \| shares					8,030,295
IPO \| Common Stock
Subsidiary Sale Of Stock [Line Items]
Common stock shares issued and sold \| shares		8,030,295
Share price per share \| $ / shares		$ 19.00
Proceeds from issuance initial public offering		$ 152,600
Net proceeds after deducting underwriting discounts and estimated offering expenses		$ 138,500

Summary of Significant Accounting Policies - Additional Information (Details)	Sep. 30, 2021
ASU 2018-13
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Change in accounting principle, accounting standards update, adopted	true
Change in accounting principle, accounting standards update, adoption date	Jan. 01, 2020
Change in accounting principle, accounting standards update, immaterial effect	true
ASU 2019-12
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Change in accounting principle, accounting standards update, adopted	true
Change in accounting principle, accounting standards update, adoption date	Jan. 01, 2020
Change in accounting principle, accounting standards update, immaterial effect	true

- Definition

Indicates (true false) whether accounting standards update was adopted.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 65
-Paragraph 15
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121322162&loc=SL121327923-165333

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=124431687&loc=d3e22499-107794

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 20
-Section 65
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=121483254&loc=SL120254523-199619

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 10
-Section 65
-Paragraph 4
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=122640432&loc=SL121648383-210437

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S65
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=124359872&loc=SL124427846-239511

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 20
-Section 65
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=124402435&loc=SL124402458-218513

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 65
-Paragraph 8
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123459177&loc=SL121830611-158277

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 10
-Section 65
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=122640432&loc=SL121648383-210437

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 926
-SubTopic 20
-Section 65
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=120154821&loc=SL120154904-197079

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 926
-SubTopic 20
-Section 65
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=120154821&loc=SL120154904-197079

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 65
-Paragraph 7
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123597120&loc=SL122642865-165497

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 65
-Paragraph 7
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123597120&loc=SL122642865-165497

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 65
-Paragraph 5
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123597120&loc=SL120254526-165497

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 65
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=123597120&loc=SL120254526-165497

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 65
-Paragraph 15
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=121322162&loc=SL121327923-165333

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 65
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121322162&loc=SL121327923-165333

Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 10
-Section 65
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=122640432&loc=SL120254519-210437

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 10
-Section 65
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123341672&loc=SL120154346-209984

Reference 19: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 848
-SubTopic 10
-Section 65
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=122150657&loc=SL122150809-237846

Reference 20: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 20
-Section 65
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=124402435&loc=SL124402458-218513

Reference 21: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 40
-Section 65
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=124501264&loc=SL117420844-207641

Reference 22: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 40
-Section 65
-Paragraph 1
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=123482062&loc=SL123482106-238011

Reference 23: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 65
-Paragraph 6
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123597120&loc=SL121967933-165497

Reference 24: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 10
-Section 65
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=122640432&loc=SL120320025-210437

Reference 25: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 105
-SubTopic 10
-Section 65
-Paragraph 6
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=124434974&loc=SL124442142-165695

Reference 26: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 65
-Paragraph 6
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123597120&loc=SL121967933-165497

Reference 27: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 10
-Section 65
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=122640432&loc=SL120320025-210437

Reference 28: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 105
-SubTopic 10
-Section 65
-Paragraph 6
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=124434974&loc=SL124442142-165695

Reference 29: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 40
-Section 65
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=124501264&loc=SL117420844-207641

Reference 30: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 40
-Section 65
-Paragraph 1
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=123482062&loc=SL123482106-238011

Reference 31: http://www.xbrl.org/2003/role/disclosureRef
-Topic 848
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 2
-Publisher FASB
-Subparagraph (a)

Reference 32: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 45
-Paragraph 24
-URI http://asc.fasb.org/extlink&oid=124436220&loc=d3e21930-107793

Reference 33: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 45
-Paragraph 23
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=124436220&loc=d3e21914-107793

+ Details

- Definition

Date accounting standards update was adopted, in YYYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S65
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=124359872&loc=SL124427846-239511

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 20
-Section 65
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=124402435&loc=SL124402458-218513

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 40
-Section 65
-Paragraph 1
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=123482062&loc=SL123482106-238011

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 65
-Paragraph 7
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123597120&loc=SL122642865-165497

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 65
-Paragraph 5
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123597120&loc=SL120254526-165497

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 20
-Section 65
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=124402435&loc=SL124402458-218513

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 10
-Section 65
-Paragraph 4
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=122640432&loc=SL121648383-210437

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 10
-Section 65
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=122640432&loc=SL120320025-210437

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 105
-SubTopic 10
-Section 65
-Paragraph 6
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=124434974&loc=SL124442142-165695

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 105
-SubTopic 10
-Section 65
-Paragraph 6
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=124434974&loc=SL124442142-165695

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 10
-Section 65
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=122640432&loc=SL120320025-210437

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 926
-SubTopic 20
-Section 65
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=120154821&loc=SL120154904-197079

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 65
-Paragraph 7
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123597120&loc=SL122642865-165497

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 65
-Paragraph 6
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123597120&loc=SL121967933-165497

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 40
-Section 65
-Paragraph 1
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=123482062&loc=SL123482106-238011

Reference 16: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=124431687&loc=d3e22583-107794

Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 40
-Section 65
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=124501264&loc=SL117420844-207641

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 40
-Section 65
-Paragraph 1
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=123482062&loc=SL123482106-238011

Reference 19: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 40
-Section 65
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=124501264&loc=SL117420844-207641

Reference 20: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 848
-SubTopic 10
-Section 65
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=122150657&loc=SL122150809-237846

Reference 21: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 65
-Paragraph 15
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121322162&loc=SL121327923-165333

Reference 22: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 40
-Section 65
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=123482062&loc=SL123482106-238011

Reference 23: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 10
-Section 65
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123341672&loc=SL120154346-209984

Reference 24: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 65
-Paragraph 8
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123459177&loc=SL121830611-158277

Reference 25: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 20
-Section 65
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=121483254&loc=SL120254523-199619

Reference 26: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 10
-Section 65
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=122640432&loc=SL121648383-210437

Reference 27: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 926
-SubTopic 20
-Section 65
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=120154821&loc=SL120154904-197079

Reference 28: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 65
-Paragraph 6
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123597120&loc=SL121967933-165497

Reference 29: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 65
-Paragraph 15
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=121322162&loc=SL121327923-165333

Reference 30: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 65
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121322162&loc=SL121327923-165333

Reference 31: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 10
-Section 65
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=122640432&loc=SL120254519-210437

Reference 32: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 65
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=123597120&loc=SL120254526-165497

Reference 33: http://www.xbrl.org/2003/role/disclosureRef
-Topic 848
-SubTopic 10
-Name Accounting Standards Codification
-Section 65
-Paragraph 2
-Publisher FASB
-Subparagraph (a)

Reference 34: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 45
-Paragraph 24
-URI http://asc.fasb.org/extlink&oid=124436220&loc=d3e21930-107793

Reference 35: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 45
-Paragraph 23
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=124436220&loc=d3e21914-107793

+ Details

Marketable Securities - Summary of Marketable Securities (Details) $ in Thousands	Sep. 30, 2021 USD ($)
Marketable Securities [Line Items]
Fair Value	$ 147,129
Marketable Securities
Marketable Securities [Line Items]
Amortized Cost	147,198
Unrealized Gains	17
Unrealized Losses	(86)
Fair Value	147,129
Marketable Securities \| Commercial Paper
Marketable Securities [Line Items]
Amortized Cost	52,965
Unrealized Gains	3
Unrealized Losses	(4)
Fair Value	52,964
Marketable Securities \| Corporate Bonds
Marketable Securities [Line Items]
Amortized Cost	87,233
Unrealized Gains	14
Unrealized Losses	(77)
Fair Value	87,170
Marketable Securities \| U.S. Government Agencies
Marketable Securities [Line Items]
Amortized Cost	7,000
Unrealized Losses	(5)
Fair Value	$ 6,995

Marketable Securities - Additional Information (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2021 USD ($)
Marketable Securities [Line Items]
Marketable securities, fair value	$ 147,129
Impairment of investments	0
Corporate Bonds and U.S. Government Agencies
Marketable Securities [Line Items]
Marketable securities, fair value	65,600
Marketable securities, unrealized loss position, fair value	51,100
Corporate Bonds
Marketable Securities [Line Items]
Marketable securities, unrealized loss position, fair value	16
Commercial Paper and U.S. Government Agencies
Marketable Securities [Line Items]
Marketable securities, unrealized loss position, fair value	$ 53
Minimum \| Corporate Bonds and U.S. Government Agencies
Marketable Securities [Line Items]
Marketable securities remaining maturity term	1 year
Marketable securities unrealized loss position, maturity term	1 year
Minimum \| Commercial Paper and U.S. Government Agencies
Marketable Securities [Line Items]
Marketable securities unrealized loss position, maturity term	1 year
Maximum \| Commercial Paper
Marketable Securities [Line Items]
Marketable securities remaining maturity term	1 year
Marketable securities unrealized loss position, maturity term	1 year
Maximum \| Corporate Bonds and U.S. Government Agencies
Marketable Securities [Line Items]
Marketable securities remaining maturity term	3 years
Marketable securities unrealized loss position, maturity term	3 years
Maximum \| Corporate Bonds
Marketable Securities [Line Items]
Marketable securities unrealized loss position, maturity term	1 year

Property and Equipment, Net - Summary of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Property Plant And Equipment [Line Items]
Total property and equipment	$ 3,939	$ 1,861
Less accumulated depreciation and amortization	(879)	(595)
Property and equipment, net	3,060	1,266
Research Equipment
Property Plant And Equipment [Line Items]
Total property and equipment	3,387	1,767
Office Equipment and Furniture
Property Plant And Equipment [Line Items]
Total property and equipment	475	$ 94
Leaseholder Improvement
Property Plant And Equipment [Line Items]
Total property and equipment	$ 77

Property and Equipment, Net - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Property Plant And Equipment [Abstract]
Depreciation and amortization expense	$ 136	$ 64	$ 356	$ 139

Other Current Liabilities - Summary of Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Other Liabilities Disclosure [Abstract]
Compensation and benefits	$ 1,615	$ 916
Other	35	32
Total other current liabilities	$ 1,650	$ 948

Debt - Additional Information (Details) - PPP Loan - USD ($) $ in Thousands	Aug. 06, 2021	May 31, 2020
Debt Instrument [Line Items]
Debt instrument, face amount		$ 567
Debt instrument, interest rate		1.00%
Debt Forgiveness
Debt Instrument [Line Items]
Debt instrument, face amount	$ 567

Fair Value Measurements - Schedule of Financial Assets And Liabilities Measured at Fair Value on Recurring Basis (Details) - Fair Value Measurements Recurring Basis $ in Thousands	Sep. 30, 2021 USD ($)
Assets:
Total	$ 154,983
Level 1
Assets:
Total	7,854
Level 2
Assets:
Total	147,129
Money Market Funds
Assets:
Cash equivalents fair value disclosure	7,854
Money Market Funds \| Level 1
Assets:
Cash equivalents fair value disclosure	7,854
Commercial Paper
Assets:
Investments fair value disclosure	52,964
Commercial Paper \| Level 2
Assets:
Investments fair value disclosure	52,964
Corporate Bonds
Assets:
Investments fair value disclosure	87,170
Corporate Bonds \| Level 2
Assets:
Investments fair value disclosure	87,170
U.S. Government Agencies
Assets:
Investments fair value disclosure	6,995
U.S. Government Agencies \| Level 2
Assets:
Investments fair value disclosure	$ 6,995

Fair Value Measurements - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value adjustments on embedded debt derivatives				$ 995,000
Fair value of embedded derivative		$ 0		0
Fair value, transfer of liabilities, from level 1 to level 2	$ 0	0	$ 0	0
Fair value, transfer of liabilities from level 2 to level 1	0	0	0	0
Fair value, transfer of assets into level 3	0	0	0	0
Fair value, transfer of assets out of level 3	0	0	0	0
Fair value, transfer of liabilities into level 3	0	0	0	0
Fair value, transfer of liabilities out of level 3	$ 0	$ 0	$ 0	0
Other income
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Fair value adjustments on embedded debt derivatives				$ 1,000,000.0

Fair Value Measurements - Schedule of Reconciliation of Embedded Debt Derivatives Measured Fair Value on Recurring Basis (Details) - Fair Value of Recurring - Level 3 $ in Thousands	9 Months Ended
	Sep. 30, 2020 USD ($)
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Balance at December 31, 2019	$ 3,920
Change in fair value	(995)
Settlement	$ (2,925)

Commitments and Contingencies - Additional Information (Details)			3 Months Ended		9 Months Ended		12 Months Ended
	Jun. 29, 2021 USD ($)	Jun. 11, 2021 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Dec. 31, 2017 USD ($) Officer
Sale Leaseback Transaction [Line Items]
Lease expiration year					2027
Operating lease, expense			$ 414,000	$ 295,000	$ 920,000	$ 995,000
Letters of credit agreements outstanding amount			$ 678,000		678,000
Finance lease, principal payments	$ 7,000	$ 13,000			$ 28,000	$ 31,000
Finance lease, term	4 years	4 years
Lease payment, term	monthly	monthly
Sale of equipment	$ 293,000
Number of former officers \| Officer							2
Loss contingency allegations claims							$ 0
Loss contingency, allegations					The Company believes that there is no merit to the claims alleged against the Company and its former officers, including no alleged breach of contract by the Company, and intends to vigorously defend against the claims pertaining to the Company and its former officers.
Maximum
Sale Leaseback Transaction [Line Items]
Percentage of equipment cost	15.00%
Additional renew of lease term	2 years
Minimum
Sale Leaseback Transaction [Line Items]
Additional renew of lease term	1 year

Commitments and Contingencies - Schedule of Future Annual Minimum Payments Under Noncancellable Operating Lease (Details) $ in Thousands	Sep. 30, 2021 USD ($)
Commitments And Contingencies Disclosure [Abstract]
Remainder of 2021	$ 391
2022	1,585
2023	1,606
2024	1,641
2025	1,688
2026	1,415
2027	59
Total operating lease obligations	$ 8,385

Commitments and Contingencies - Schedule of Future Annual Minimum Payments Under Capitalized Lease (Details) $ in Thousands	Sep. 30, 2021 USD ($)
Commitments And Contingencies Disclosure [Abstract]
Remainder of 2021	$ 94
2022	239
2023	239
2024	239
2025	139
Total capital lease obligations	950
Less amount representing interest	(52)
Present value of minimum capital lease obligations	$ 898

Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions		1 Months Ended
	Feb. 08, 2021	Feb. 28, 2021	Jan. 31, 2021	Sep. 30, 2021	Dec. 31, 2020
Class Of Stock [Line Items]
Common stock, shares authorized				1,230,000,000	1,230,000,000
IPO
Class Of Stock [Line Items]
Common stock shares issued and sold		8,030,295
Partial exercise of the underwriters option to purchase additional shares		1,030,243
Sale of Stock, Price Per Share		$ 19.00
Aggregate gross proceeds from issuance of initial public offering		$ 152.6
Net proceeds after deducting underwriting discounts		$ 138.5
Outstanding preferred stock converted into aggregate shares of common stock	19,034,069
Common stock, shares authorized	250,000,000
Preferred stock, shares authorized	10,000,000
Series BB Convertible Preferred Stock Issuance
Class Of Stock [Line Items]
Convertible preferred stock shares issued and sold			113,275,902
Convertible preferred stock per share			$ 0.207383
Proceeds on the issuance of convertible preferred stock			$ 23.5

Equity - Summary of Common Stock Warrant activity (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Class Of Stock [Line Items]
Number of Common Stock Warrants Outstanding, Beginning Balance	57,212
Number of Common Stock Warrants Outstanding, Ending Balance		57,212
Weighted-Average Exercise Price Outstanding, Beginning Balance	$ 7.62
Weighted-Average Exercise Price Outstanding, Ending Balance		$ 7.62
Weighted-Average Remaining Contractual Term, Outstanding		3 years 7 months 20 days
Aggregate Intrinsic Value Outstanding		$ 98
Warrant \| Equity and Debt Fundraising Events
Class Of Stock [Line Items]
Number of Common Stock Warrants Outstanding, Beginning Balance	412,262
Number of Common Stock Warrants, Granted	1,648,709
Number of Common Stock Warrants, Exercised	(1,648,709)
Number of Common Stock Warrants Outstanding, Ending Balance	412,262	412,262
Weighted-Average Exercise Price Outstanding, Beginning Balance	$ 9.60
Weighted Average Exercise Price, Granted	0.01
Weighted Average Exercise Price, Exercised	(0.01)
Weighted-Average Exercise Price Outstanding, Ending Balance	$ 9.60	$ 9.60
Weighted-Average Remaining Contractual Term, Outstanding	5 years 11 months 15 days	6 years 8 months 15 days
Aggregate Intrinsic Value Outstanding	$ 2,561	$ 1,380

Stock-Based Compensation - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Recognized share-based compensation expense	$ 1,736,000	$ 781,000	$ 4,830,000	$ 1,138,000
Grant dates at weighted average fair value			$ 16.51
Options available for grant			1,620,159
Options vested			$ 2,500,000
Unrecognized stock-based compensation expense	19,700,000		$ 19,700,000
Weighted-average period			3 years 1 month 24 days
Common Stock Warrants
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized stock-based compensation expense	$ 0		$ 0
2021 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares reserved for issuance	5,000,000		5,000,000
Number of capital stock outstanding percentage			4.00%
Grant dates at weighted average fair value			$ 12.58
Options available for grant			1,388,736
2021 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares reserved for issuance	333,333		333,333
Percentage of number of shares of capital stock outstanding on last day of preceding year			1.00%
Recognized share-based compensation expense			$ 0
Purchase price of fair value common stock, percent			85.00%
2018 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Grant dates at weighted average fair value			$ 12.58

Stock-Based Compensation - Summary of Stock Option Award Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Stock Options, Outstanding balance	1,947,123
Number of Stock Options, Granted	1,620,159
Number of Stock Options, Forfeited	(303,082)
Number of Stock Options, Outstanding balance	3,264,200	1,947,123
Number of Stock Options, Exercisable	793,677
Number of Stock Options, Options expected to vest	2,470,523
Weighted-Average Exercise Price, Outstanding balance	$ 5.70
Grant dates at weighted average fair value	16.51
Weighted-Average Exercise Price, Forfeited	(5.91)
Weighted-Average Exercise Price,Outstanding balance	11.04	$ 5.70
Weighted-Average Exercise Price, Exercisable	10.66
Weighted-Average Exercise Price, Options expected to vest	$ 11.16
Weighted-Average Remaining Contractual Term, Outstanding balance	9 years 7 days	9 years 6 months 21 days
Weighted-Average Remaining Contractual Term, Exercisable	8 years 6 months 18 days
Weighted-Average Remaining Contractual Term, Options expected to vest	9 years 2 months 23 days
Aggregate Intrinsic Value, Outstanding	$ 14,804	$ 10,284
Aggregate Intrinsic Value, Exercisable	6,310
Aggregate Intrinsic Value, Options expected to vest	$ 8,494

Stock-Based Compensation - Summary of Employee-issued Common Stock Warrant Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Common Stock Warrants Outstanding, Beginning Balance	57,212
Number of Common Stock Warrants Outstanding and Exercisable, Ending Balance	57,212
Weighted-Average Exercise Price Outstanding, Beginning Balance	$ 7.62
Weighted-Average Exercise Price Outstanding and Exercisable, Ending Balance	$ 7.62
Weighted-Average Remaining Contractual Term Outstanding		3 years 7 months 20 days
Weighted-Average Remaining Contractual Term Outstanding and Exercisable	2 years 10 months 20 days
Aggregate Intrinsic Value Outstanding	$ 98
Aggregate Intrinsic Value Outstanding and Exercisable	$ 269

Stock-Based Compensation - Summary of Fair Value Assumptions and Methodology (Details)	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Volatility, Minimum	89.31%
Volatility		90.00%
Volatility, Maximum	98.04%
Risk-free interest rate, Minimum	0.40%	0.11%
Risk-free interest rate, Maximum	1.20%	0.18%
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected life (years)	5 years 6 months 7 days	6 months
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected life (years)	6 years 29 days	4 years

Stock-Based Compensation - Summary of Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 1,736	$ 781	$ 4,830	$ 1,138
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	691	340	1,839	441
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 1,045	$ 441	$ 2,991	$ 697

Employee Retirement Plan - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Defined Benefit Plan Disclosure [Line Items]
Company's matching contributions vesting percentage			100.00%
Accrued expense	$ 62	$ 26	$ 167	$ 78
Maximum
Defined Benefit Plan Disclosure [Line Items]
Percentage of company matching contributions of employee's base salary			4.00%

Related-Party Transactions - Additional Information (Details) - Consulting Agreement - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Jan. 31, 2021	Dec. 31, 2020
Related Party Transaction [Line Items]
Consulting services fee		$ 1,500
Consultation service fee payment		$ 1,125
Payment for consulting services	$ 1,500
Remaining consultation fee recorded as expense	$ 375

Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Provision for income taxes	$ 0	$ 0	$ 0	$ 0

- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References + Details

Net Loss Per Share - Schedule of Basic and Diluted Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share [Abstract]
Net loss	$ (9,685)	$ (9,771)	$ (7,972)	$ (5,367)	$ (4,910)	$ (4,692)	$ (27,428)	$ (14,969)
Cumulative dividends on convertible preferred stock								(104)
Net loss attributable to common stockholders	$ (9,685)			$ (5,367)			$ (27,428)	$ (15,073)
Net loss per common share, basic and diluted	$ (0.32)			$ (3.00)			$ (1.03)	$ (9.82)
Weighted-average number of shares used in computing net loss per common share, basic and diluted	30,588,495			1,787,124			26,736,745	1,535,033

- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(22))
-URI http://asc.fasb.org/extlink&oid=120399700&loc=SL114874048-224260

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8933-108599

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=124431687&loc=d3e22595-107794

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(18))
-URI http://asc.fasb.org/extlink&oid=120400993&loc=SL114874131-224263

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 40
-Section 65
-Paragraph 1
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=123482062&loc=SL123482106-238011

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=124431353&loc=SL124452729-227067

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(5))
-URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442552-122756

Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(20))
-URI http://asc.fasb.org/extlink&oid=123367319&loc=SL114868664-224227

Reference 9: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3602-108585

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=124431687&loc=d3e22499-107794

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(iv))
-URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442526-122756

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(iii)(A))
-URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442526-122756

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(i))
-URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442552-122756

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(i))
-URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442526-122756

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=124431687&loc=d3e22663-107794

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iv))
-URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442552-122756

Reference 17: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(ii))
-URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442526-122756

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 28
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=123596393&loc=d3e14064-108612

Reference 19: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=124431687&loc=d3e22583-107794

Reference 20: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(g)(1)(ii))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

Reference 21: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 60B
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=125511455&loc=SL5780133-109256

Reference 22: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571

Reference 23: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=124431687&loc=d3e22658-107794

Reference 24: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 1A
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=124509347&loc=SL7669619-108580

Reference 25: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 31
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8924-108599

Reference 26: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 11
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=124431687&loc=d3e22694-107794

Reference 27: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 11
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=124431687&loc=d3e22694-107794

Reference 28: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=109222650&loc=SL51721683-107760

Reference 29: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 1B
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=124509347&loc=SL7669625-108580

Reference 30: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8736-108599

Reference 31: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(5))
-URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442526-122756

Reference 32: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iii)(B))
-URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442552-122756

Reference 33: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iii)(A))
-URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442552-122756

Reference 34: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8906-108599

Reference 35: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8933-108599

+ Details

- Definition

Amount, after deduction of tax, noncontrolling interests, dividends on preferred stock and participating securities; of income (loss) available to common shareholders.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=124431687&loc=d3e22595-107794

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=125511455&loc=d3e1448-109256

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 11
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=124431687&loc=d3e22694-107794

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=125511455&loc=d3e1377-109256

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=124432515&loc=d3e3550-109257

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8736-108599

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 11
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=124431687&loc=d3e22694-107794

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 60B
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=125511455&loc=SL5780133-109256

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8933-108599

Reference 10: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 31
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8924-108599

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8906-108599

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=124431687&loc=d3e22583-107794

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8933-108599

+ Details

Net Loss Per Share - Potentially Dilutive Securities Excluded from Calculation of Diluted Net Loss Per Share (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Convertible Preferred Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from calculation of diluted net loss per share		630,592,111		630,592,111
Stock Options to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from calculation of diluted net loss per share	3,264,200	1,660,864	3,264,200	1,660,864
Warrants Issued to Employees and Contractor to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from calculation of diluted net loss per share	57,212	57,420	57,212	57,420
Warrants Issued Related to Convertible Notes and Other Equity Agreements
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from calculation of diluted net loss per share	412,262	412,262	412,262	412,262