Rein Therapeutics (RNTX) 10-Q 15 Aug 22 2022 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2022	Aug. 11, 2022
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q2
Trading Symbol	ALRN
Entity Registrant Name	Aileron Therapeutics, Inc.
Entity Central Index Key	0001420565
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Common Stock, Shares Outstanding		90,823,597
Entity File Number	001-38130
Entity Tax Identification Number	13-4196017
Entity Address, Address Line One	285 Summer Street
Entity Address, Address Line Two	Suite 101
Entity Address, City or Town	Boston
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02210
City Area Code	617
Local Phone Number	995-0900
Entity Shell Company	false
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Document Quarterly Report	true
Document Transition Report	false
Entity Incorporation, State or Country Code	DE
Title of 12(b) Security	Common Stock, $0.001 par value per share
Security Exchange Name	NASDAQ

Condensed Balance Sheets

Condensed Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 7,628	$ 3,600
Investments	24,754	42,333
Prepaid expenses and other current assets	1,143	2,219
Restricted cash	25	25
Total current assets	33,550	48,177
Operating lease, right-of-use asset	98	152
Other non-current assets	24	24
Property and equipment, net	98	128
Total assets	33,770	48,481
Current liabilities:
Accounts payable	1,741	1,210
Accrued expenses and other current liabilities	3,310	3,205
Operating lease liability, current portion	100	93
Total current liabilities	5,151	4,508
Operating lease liability, net of current portion		69
Total liabilities	5,151	4,577
Commitments and contingencies (Note 11)
Stockholders’ equity:
Preferred stock, $0.001 par value; 5,000,000 shares authorized and no shares issued and outstanding at June 30, 2022 and December 31, 2021, respectively
Common stock, $0.001 par value; 300,000,000 shares authorized at June 30, 2022 and December 31, 2021, respectively; 90,823,597 and 90,573,597 shares issued and outstanding at June 30, 2022 and December 31, 2021, respectively	91	91
Additional paid-in capital	290,499	289,282
Accumulated other comprehensive loss	(101)	(13)
Accumulated deficit	(261,870)	(245,456)
Total stockholders’ equity	28,619	43,904
Total liabilities and stockholders’ equity	$ 33,770	$ 48,481

Condensed Balance Sheets (Paren

Condensed Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	300,000,000	300,000,000
Common stock, shares issued	90,823,597	90,573,597
Common stock, shares outstanding	90,823,597	90,573,597

Condensed Statements of Operati

Condensed Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Income Statement [Abstract]
Revenue	$ 0	$ 0	$ 0	$ 0
Operating expenses:
Research and development	5,433	3,853	11,326	8,169
General and administrative	2,608	2,156	5,136	4,829
Total operating expenses	8,041	6,009	16,462	12,998
Loss from operations	(8,041)	(6,009)	(16,462)	(12,998)
Interest income	49	19	70	33
Other income (expense), net	0	304	(22)	304
Net loss	$ (7,992)	$ (5,686)	$ (16,414)	$ (12,661)
Net loss per share - basic	$ (0.09)	$ (0.06)	$ (0.18)	$ (0.15)
Net loss per share - diluted	$ (0.09)	$ (0.06)	$ (0.18)	$ (0.15)
Weighted average common shares outstanding - basic	90,823,597	90,458,550	90,749,011	86,941,002
Weighted average common shares outstanding - diluted	90,823,597	90,458,550	90,749,011	86,941,002
Comprehensive loss:
Net loss	$ (7,992)	$ (5,686)	$ (16,414)	$ (12,661)
Other comprehensive loss:
Unrealized gain (loss) on investments, net of tax of $0	(26)	13	(88)	8
Total other comprehensive income (loss)	(26)	13	(88)	8
Total comprehensive loss	$ (8,018)	$ (5,673)	$ (16,502)	$ (12,653)

Condensed Statements of Opera_2

Condensed Statements of Operations and Comprehensive Loss (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Income Statement [Abstract]
Unrealized gain (loss) on investments, tax	$ 0	$ 0	$ 0	$ 0

Condensed Statement of Stockhol

Condensed Statement of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Accumulated Deficit [Member]
Beginning balance at Dec. 31, 2020	$ 12,162	$ 44	$ 231,412	$ (2)	$ (219,292)
Beginning balance, shares at Dec. 31, 2020		43,804,175
Issuance of common stock	59,088	$ 46	59,042
Issuance of common stock, shares		46,406,382
Issuance costs	(3,482)		(3,482)
Stock-based compensation expense	631		631
Unrealized gain (loss) on investments	(5)			(5)
Net loss	(6,975)				(6,975)
Ending balance at Mar. 31, 2021	61,419	$ 90	287,603	(7)	(226,267)
Ending balance, shares at Mar. 31, 2021		90,210,557
Beginning balance at Dec. 31, 2020	12,162	$ 44	231,412	(2)	(219,292)
Beginning balance, shares at Dec. 31, 2020		43,804,175
Unrealized gain (loss) on investments	8
Net loss	(12,661)
Ending balance at Jun. 30, 2021	56,130	$ 90	287,987	6	(231,953)
Ending balance, shares at Jun. 30, 2021		90,527,914
Beginning balance at Mar. 31, 2021	61,419	$ 90	287,603	(7)	(226,267)
Beginning balance, shares at Mar. 31, 2021		90,210,557
Exercise of stock options, Shares		67,357
Exercise of stock options	47		47
Issuance costs	(24)		(24)
RSU's vested, net of shares withheld/repurchased for tax	0
RSU's vested, net of shares withheld/repurchased for tax, Shares		250,000
Stock-based compensation expense	361		361
Unrealized gain (loss) on investments	13			13
Net loss	(5,686)				(5,686)
Ending balance at Jun. 30, 2021	56,130	$ 90	287,987	6	(231,953)
Ending balance, shares at Jun. 30, 2021		90,527,914
Beginning balance at Dec. 31, 2021	$ 43,904	$ 91	289,282	(13)	(245,456)
Beginning balance, shares at Dec. 31, 2021	90,573,597	90,573,597
RSU's vested, net of shares withheld/repurchased for tax	$ 0
RSU's vested, net of shares withheld/repurchased for tax, Shares		250,000
Stock-based compensation expense	689		689
Unrealized gain (loss) on investments	(62)			(62)
Net loss	(8,422)				(8,422)
Ending balance at Mar. 31, 2022	36,109	$ 91	289,971	(75)	(253,878)
Ending balance, shares at Mar. 31, 2022		90,823,597
Beginning balance at Dec. 31, 2021	$ 43,904	$ 91	289,282	(13)	(245,456)
Beginning balance, shares at Dec. 31, 2021	90,573,597	90,573,597
Exercise of stock options, Shares	0
Unrealized gain (loss) on investments	$ (88)
Net loss	(16,414)
Ending balance at Jun. 30, 2022	$ 28,619	$ 91	290,499	(101)	(261,870)
Ending balance, shares at Jun. 30, 2022	90,823,597	90,823,597
Beginning balance at Mar. 31, 2022	$ 36,109	$ 91	289,971	(75)	(253,878)
Beginning balance, shares at Mar. 31, 2022		90,823,597
Stock-based compensation expense	528		528
Unrealized gain (loss) on investments	(26)			(26)
Net loss	(7,992)				(7,992)
Ending balance at Jun. 30, 2022	$ 28,619	$ 91	$ 290,499	$ (101)	$ (261,870)
Ending balance, shares at Jun. 30, 2022	90,823,597	90,823,597

Statements of Cash Flows

Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Cash flows from operating activities:
Net loss	$ (16,414)	$ (12,661)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization expense	83	42
Forgiveness of paycheck protection program loan		(387)
Net amortization of premiums and discounts on investments	(21)	140
Stock-based compensation expense	1,217	993
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	1,076	1,280
Other assets		(24)
Accounts payable	531	(583)
Operating lease liabilities	(62)	(7)
Accrued expenses and other current liabilities	105	968
Net cash used in operating activities	(13,485)	(10,239)
Cash flows from investing activities:
Purchases of property and equipment		(152)
Purchases of investments	(12,098)	(51,105)
Proceeds from sales or maturities of investments	29,611	9,000
Net cash provided by (used in) investing activities	17,513	(42,257)
Cash flows from financing activities:
Proceeds from issuance of common stock, net of issuance costs		55,583
Proceeds from exercise of stock options		47
Net cash provided by financing activities		55,630
Net increase in cash, cash equivalents and restricted cash	4,028	3,134
Cash, cash equivalents and restricted cash at beginning of period	3,625	7,639
Cash, cash equivalents and restricted cash at end of period	$ 7,653	$ 10,773

Nature of the Business and Basi

Nature of the Business and Basis of Presentation	6 Months Ended
	Jun. 30, 2022
Accounting Policies [Abstract]
Nature of the Business and Basis of Presentation	1 . Nature of the Business and Basis of Presentation Aileron Therapeutics, Inc. (“Aileron” or the “Company”) is a clinical stage chemoprotection oncology company focused on developing medicines to make chemotherapy safer and thereby more effective to save more patients’ lives. ALRN-6924, the Company’s first-in-class MDM2/MDMX dual inhibitor, is designed to activate p53, which in turn upregulates p21, a known inhibitor of the cell replication cycle. ALRN-6924 is the only reported chemoprotective agent in clinical development to employ a biomarker strategy, in which the Company exclusively focuses on treating patients with p53-mutated cancers. The Company’s targeted strategy is designed to selectively protect multiple healthy cell types throughout the body from chemotherapy without protecting cancer cells. The Company is subject to risks common to companies in the biotechnology industry, including but not limited to, new technological innovations, protection of proprietary technology, dependence on key personnel, compliance with government regulations, uncertainties in the clinical development of product candidates and in the ability to obtain needed additional financing. ALRN-6924 will require significant additional research and development efforts, including preclinical and clinical testing and regulatory approval prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel infrastructure and extensive compliance-reporting capabilities. There can be no assurance that the Company’s research and development of ALRN-6924 will be successfully completed, that adequate protection for the Company’s intellectual property will be obtained, that ALRN-6924 will obtain necessary governmental regulatory approval or that if approved, will be commercially viable. Even if the Company’s drug development efforts are successful, it is uncertain when, if ever, the Company will generate significant revenue from product sales. The Company operates in an environment of rapid change in technology and substantial competition from pharmaceutical and biotechnology companies. In addition, the Company is dependent upon the services of its key employees and consultants. The accompanying financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”). Liquidity In accordance with Accounting Standards Update (“ASU”) No. 2014-15, Disclosures of Uncertainties about an Entity’s Ability to Continue as a Going Concern (Subtopic 205-40), management must evaluate whether there are conditions or events, considered in the aggregate, that raise substantial doubt about the company’s ability to continue as a going concern within one year after the date that the financial statements are issued. This evaluation initially does not take into consideration the potential mitigating effect of management’s plans that have not been fully implemented as of the date the financial statements are issued. When substantial doubt exists under this methodology, management evaluates whether the mitigating effect of its plans sufficiently alleviates substantial doubt about the company’s ability to continue as a going concern. The mitigating effect of management’s plans, however, is only considered if both (1) it is probable that the plans will be effectively implemented within one year after the date that the financial statements are issued, and (2) it is probable that the plans, when implemented, will mitigate the relevant conditions or events that raise substantial doubt about the entity’s ability to continue as a going concern within one year after the date that the financial statements are issued. Generally, to be considered probable of being effectively implemented, the plans must have been approved before the date that the financial statements are issued. The Company’s interim financial statements have been prepared on a going concern basis, which contemplates the continuity of operations, realization of assets and the satisfaction of liabilities in the ordinary course of business. Through June 30, 2022 , the Company has financed operations primarily through $ 145,467 in net proceeds from sales of common stock, $ 131,211 from sales of preferred stock prior to its IPO, and $ 34,910 from a collaboration agreement in 2010. As of June 30, 2022, the Company had cash, cash equivalents and investments of $ 32,382 . The Company has incurred losses and negative cash flows from operations and had an accumulated deficit of $ 261,870 as of June 30, 2022. The Company expects to continue to generate losses for the foreseeable future. The Company believes that, based on its current operating plan, its cash, cash equivalents and investments of $ 32,382 as of June 30, 2022 will enable the Company to fund its operating expenses for greater than twelve months from the date of issuance of these financial statements. To execute its business plans beyond the next twelve months, the Company will need substantial funding 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 the sale of common stock in public offering and/or private placements, debt financings or other capital sources, including collaborations with other companies or other strategic transactions. The Company may not be able to obtain financing when needed, on acceptable terms or at all. The terms of any financing may adversely affect the holdings or the rights of the Company’s stockholders. If the Company is unable to obtain funding, the Company could be forced to delay, reduce or eliminate some or all of its clinical programs or future commercialization efforts, which could adversely affect its business prospects. The interim financial statements do not include any adjustments that might result from the outcome of this uncertainty.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2022
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2 . Summary of Significant Accounting Policies Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities as of the date of the financial statements and the reported amounts of expenses during the reporting periods. Significant estimates and assumptions reflected in these financial statements include, but are not limited to, the accrual of research and development expenses and the valuation of common stock based on stock-based awards. Estimates are periodically reviewed in light of changes in circumstances, facts and experience. Actual results could differ from the Company's estimates. Unaudited Interim Financial Information The accompanying unaudited condensed financial statements as of June 30, 2022 and for the three and six months ended June 30, 2022 and 2021 have been prepared by the Company pursuant to the rules and regulations of the United States Securities and Exchange Commission (“SEC”) for interim financial statements. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. However, the Company believes that the disclosures are adequate to make the information presented not misleading. These financial statements should be read in conjunction with the Company’s audited financial statements and the notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2021 that was filed with the SEC on March 28, 2022. The unaudited interim condensed financial statements have been prepared on the same basis as the audited financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair statement of the Company’s financial position as of June 30, 2022, the results of its operations for the three and six months ended June 30, 2022 and 2021 and its cash flows for the six months ended June 30, 2022 and 2021. The financial data and other information disclosed in these notes related to the three and six months ended June 30, 2022 and 2021 are unaudited. The results for the six months ended June 30, 2022 are not necessarily indicative of results to be expected for the year ending December 31, 2022, any other interim periods, or any future year or period. The accompanying balance sheet as of December 31, 2021 has been derived from the Company’s audited financial statements for the year ended December 31, 2021 included in the Company’s Annual Report on Form 10-K that was filed with the SEC on March 28, 2022. Our significant accounting policies are described in Note 2 to the financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2021 that was filed with the SEC on March 28, 2022. Concentration of Credit Risk and of Significant Suppliers Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash, cash equivalents and investments. From time to time, the Company has maintained all of its cash, cash equivalents and investment balances at three accredited financial institutions, in amounts that exceed federally insured limits. The Company generally invests its excess cash in money market funds, commercial paper and corporate notes that are subject to minimal credit and market risks. Management has established guidelines relative to credit ratings and maturities intended to safeguard principal balances and maintain liquidity. The investment portfolio is maintained in accordance with the Company’s investment policy, which defines allowable investments, specifies credit quality standards and limits the credit exposure of any single issuer. The Company is dependent on third-party manufacturers to supply products for research and development activities of its programs, including preclinical and clinical testing. In particular, the Company relies and expects to continue to rely on a small number of manufacturers to supply it with its requirements for the active pharmaceutical ingredients and formulated drugs related to these programs. These programs could be adversely affected by a significant interruption in the supply of active pharmaceutical ingredients and formulated drugs. Risks and Uncertainties The ongoing COVID-19 pandemic and government measures taken in response have had a significant impact, both direct and indirect, on businesses and commerce. The future progression of the pandemic and its effects on our business and operations are uncertain. Potential impacts to the Company’s business include disruptions in supply of the Company’s product candidate and/or procurement of items that are essential for the Company’s research and development activities, including, for example, raw materials used in the manufacturing of ALRN-6924, medical and laboratory supplies used in the Company’s clinical trials or preclinical studies or animals that are used for preclinical testing, in each case, for which there may be shortages because of ongoing efforts to address the COVID-19 pandemic. While the Company believes that it currently has sufficient supply of its product candidate to conduct the Company’s Phase 1b clinical trial in breast cancer, its product candidate, or materials contained therein, come from facilities located in areas impacted by the COVID-19 pandemic. Additionally, the Company has enrolled, and is seeking to enroll, cancer patients in the Company’s clinical trials at sites located both in the United States and Europe, which are areas that continue to be impacted by the COVID-19 pandemic. Enrollment at clinical trial sites has been and may continue to be disrupted as the effects of the COVID-19 pandemic persist. In the event that clinical trial sites close to enrollment in the Company’s trials or shift resources to address COVID-19, this could have a material adverse impact on the Company’s clinical trial plans and timelines. The Company may face difficulties recruiting or retaining patients in its clinical trials if patients are affected by the virus or are fearful of visiting or traveling to the Company’s clinical trial sites because of the COVID-19 pandemic. Any negative impact that the COVID-19 outbreak has on the ability of the Company’s suppliers to provide materials necessary for the Company’s product candidate or on recruiting or retaining patients in the Company’s clinical trials could cause costly delays to clinical trial activities, which could adversely affect the Company’s ability to obtain regulatory approval for and to commercialize the Company’s product candidate, increase the Company’s operating expenses, affect the Company’s ability to raise additional capital, and impact the Company’s operating and financial results. The capital markets have also experienced significant volatility as a result of the pandemic. Future disruptions in the capital markets could negatively impact the Company’s ability to raise capital in the future. Recently Issued Accounting Pronouncements In June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses (ASU 2016-13 or Topic 326): Measurement of Credit Losses on Financial Instruments, which requires the measurement and recognition of expected credit losses for financial assets held at amortized cost. ASU 2016-13 replaces the existing incurred loss impairment model with an expected loss methodology, which will result in more timely recognition of credit losses. The ASU will be effective for the Company's fiscal year beginning January 1, 2023. The Company is currently evaluating the impact of the adoption of ASU 2016-13 and does not expect adoption to have a material effect on the Company’s consolidated financial statements or disclosures. Other accounting standards that have been issued or proposed by the FASB or other standards-setting bodies that do not require adoption until a future date are not expected to have a material impact on the Company’s financial statements upon adoption.

Fair Value of Financial Assets

Fair Value of Financial Assets	6 Months Ended
	Jun. 30, 2022
Fair Value Disclosures [Abstract]
Fair Value of Financial Assets	3 . Fair Value of Financial Assets The following tables present information about the Company’s assets that are measured at fair value on a recurring basis and indicate the level of the fair value hierarchy utilized to determine such fair values: Fair Value Measurements as of Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 4,144 $ — $ — $ 4,144 Investments: Commercial paper — 16,805 — 16,805 Corporate notes — 1,250 — 1,250 Treasury bills — 6,699 — 6,699 Total Fair Value of Financial Instruments as of June 30, 2022 $ 4,144 $ 24,754 $ — $ 28,898 Fair Value Measurements as of Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 2,438 $ — $ — $ 2,438 Investments: Commercial paper — 33,969 — 33,969 Corporate notes — 6,366 — 6,366 Treasury Bills — 1,998 — 1,998 Total Fair Value of Financial Instruments as of December 31, 2021 $ 2,438 $ 42,333 $ — $ 44,771 As of June 30, 2022 and December 31, 2021 , the Company’s cash equivalents and investments were valued based on Level 1 and Level 2 inputs. In determining the fair value of its corporate notes and commercial paper at each date presented above, the Company relied on quoted prices for similar securities in active markets or using other inputs that are observable or can be corroborated by observable market data. The Company’s cash equivalents have original maturities of less than 90 days from the date of purchase. All available-for-sale investments have contractual maturities of less than one year . During the six months ended June 30, 2022 and the year ended December 31, 2021 , there were no transfers in or out of Level 3.

Investments

Investments	6 Months Ended
	Jun. 30, 2022
Investments, Debt and Equity Securities [Abstract]
Investments	4 . Investments As of June 30, 2022 and December 31, 2021, the fair value of available-for-sale investments by type of security was as follows: June 30, 2022 Amortized Gross Gross Fair Investments: Commercial paper $ 16,852 $ — $ ( 47 ) $ 16,805 Corporate notes 1,258 — ( 8 ) 1,250 Treasury Bills 6,745 — ( 46 ) 6,699 Total Investments as of June 30, 2022 $ 24,855 $ — $ ( 101 ) $ 24,754 December 31, 2021 Amortized Gross Gross Fair Investments: Commercial paper $ 33,976 $ — $ ( 7 ) $ 33,969 Corporate notes 6,368 — ( 2 ) 6,366 Treasury bills 2,002 — ( 4 ) 1,998 Total Investments as of December 31, 2021 $ 42,346 $ — $ ( 13 ) $ 42,333

Property and Equipment, Net

Property and Equipment, Net	6 Months Ended
	Jun. 30, 2022
Property, Plant and Equipment [Abstract]
Property and Equipment, Net	5 . Property and Equipment, Net Property and equipment, net consisted of the following: June 30, December 31, Computer equipment and software $ 338 $ 340 Less: Accumulated depreciation and amortization ( 240 ) ( 212 ) Total Property and Equipment, Net $ 98 $ 128 Depreciation and amortization expense for the six months ended June 30, 2022 and 2021 was $ 29 and $ 15 respectively. During the third quarter of 2021, the Company received payment for disposed, fully depreciated assets, resulting in a gain on sale of $ 66 .

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	6 Months Ended
	Jun. 30, 2022
Payables and Accruals [Abstract]
Accrued Expenses and Other Current Liabilities	6. Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consisted of the following: June 30, December 31, External research and development services $ 1,664 $ 1,575 Payroll and payroll-related costs 702 1,182 Professional fees 859 388 Other 85 60 Total Accrued Expenses and Other Liabilities $ 3,310 $ 3,205

Paycheck Protection Loan

Paycheck Protection Loan	6 Months Ended
	Jun. 30, 2022
Debt Disclosure [Abstract]
Paycheck Protection Loan	7. Paycheck Protection Loan On April 30, 2020, the Company received loan proceeds in the amount of approximately $ 384 under the Paycheck Protection Program (“PPP”). The PPP, established as part of the Coronavirus Aid, Relief and Economic Security Act (“CARES Act”), provides for loans to qualifying businesses for amounts up to 2.5 times the average monthly payroll expenses of the qualifying business. The loan and accrued interest are forgivable after eight weeks if the borrower uses the loan proceeds for eligible purposes, including payroll, benefits, rent and utilities. The amount of loan forgiveness may be reduced if the borrower terminates employees or reduces salaries during the eight-week period. The unforgiven portion of the PPP loan is payable over two years at an interest rate of 1 %, with a deferral of payments for the first six months . The Company used the proceeds for purposes consistent with the PPP. The Company determined to account for the PPP loan as debt under Accounting Standards Update (“ASC 470”), “Debt”, and allocated and recorded the loan proceeds between current and non-current liabilities. On May 20, 2021, the Small Business Administration notified the Company that the PPP loan had been forgiven in full. During the year ended December 31, 2021, the Company recognized income for debt extinguishment pursuant to ASC 470-50-15-4 as other income.

Lease

Lease	6 Months Ended
	Jun. 30, 2022
Leases [Abstract]
Lease	8. Lease On March 26, 2021, the Company entered into a sublease agreement (the “Sublease”) by and among the Company, Vittoria Industries North America, Inc. (the “Sublessor”) and Waterfront Equity Partners, LLC (the “Lessor”), under which the Company is leasing approximately 3,365 square feet of office space located at 285 Summer Street, Unit 101, Boston, Massachusetts (the “Premises”). The Sublease is subject and subordinate to a lease agreement, dated as of July 13, 2012, by and between the Sublessor and Lessor (the “Prime Lease”), pursuant to which the Sublessor is leasing the Premises from the Lessor. The term of the Sublease (the “Term”) commenced on April 1, 2021 and terminates upon the earliest to occur of (i) March 31, 2023 , (ii) early termination of the Prime Lease or (iii) termination of the Sublease pursuant to the terms thereof. The Company is obligated to pay monthly base rent under the Sublease to the Sublessor in an approximate amount of $ 12 per month during the Term. The Company recorded a right of use asset of $ 228 and operating lease liabilities of $ 217 upon the inception of the Sublease.

Common Stock

Common Stock	6 Months Ended
	Jun. 30, 2022
Equity [Abstract]
Common Stock	9. Common Stock On June 16, 2021, the Company filed a certificate of amendment to its restated certificate of incorporation which increased the authorized number of shares of common stock from 150,000,000 shares of $ 0.001 par value common stock to 300,000,000 shares of common stock. 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 entitled to receive dividends, as may be declared by the Company’s board of directors, if any, subject to the preferential dividend rights of the preferred stock. As of June 30, 2022 and December 31, 2021 , no dividends had been declared. On January 6, 2021, the Company entered into a securities purchase agreement with certain institutional investors, pursuant to which the Company issued and sold, in a registered direct offering (the “Offering”), an aggregate of 32,630,983 shares of common stock, $ 0.001 par value per share, at a purchase price per share of $ 1.10 (the “Shares”). The aggregate gross proceeds of the Offering were $ 35,894 , before deducting $ 2,887 of fees payable to the placement agent and other offering expenses payable by the Company. The Offering closed on January 8, 2021 . Between January 1, 2021 and January 28, 2021, the Company issued and sold an aggregate 7,174,993 shares of its common stock pursuant to its sales agreement with JonesTrading Institutional Services LLC (“JonesTrading”), resulting in gross proceeds of $ 9,658 , before deducting expenses of $ 290 . The Company terminated its sales agreement with Jones Trading in January 2021. On January 29, 2021, the Company entered into a Capital on Demand™ Sales Agreement (the “ATM Sales Agreement”) with JonesTrading and William Blair & Company, L.L.C. (“William Blair” and, collectively with JonesTrading, the “Agents”), pursuant to which the Company may offer and sell shares of its common stock having an aggregate offering price of up to $ 30,000 from time to time through or to the Agents (the “ATM Offering”). During the year ended December 31, 2021, the Company issued and sold an aggregate of 5,225,406 shares of its common stock pursuant to the ATM Sales Agreement, resulting in gross proceeds of $ 10,922 before deducting expenses of $ 329 . There were no sales under the ATM Sales Agreement during the six months ended June 30, 2022 . Pursuant to a prospectus relating to the ATM Sales Agreement filed by the Company with the SEC on June 21, 2022, the Company may offer and sell shares of its common stock having an aggregate offering price of up to $ 14,024,100 under the ATM Sales Agreement . During the year ended December 31, 2021, the Company issued and sold an aggregate of 1,375,000 shares of its common stock to Lincoln Park Capital, LLC pursuant to a purchase agreement entered into between Lincoln Park Capital, LLC and the Company in September 2020, resulting in gross proceeds of $ 2,614 . There were no sales under the purchase agreement during the six months ended June 30, 2022. On April 2, 2019, the Company issued and sold in a private placement an aggregate of (i) 11,838,582 units, consisting of 11,838,582 shares of its common stock and associated warrants, or the common warrants, to purchase an aggregate of 11,838,582 shares of common stock, for a combined price of $ 2.01 per unit and (ii) 1,096,741 units, consisting of (a) pre-funded warrants to purchase 1,096,741 shares of our common stock and (b) associated common warrants to purchase 1,096,741 shares of common stock, for a combined price of $ 2.01 per unit. The pre-funded warrants had an exercise price of $ 0.01 per share and had no expiration. In July 2019, all outstanding pre-funded warrants were exercised for 1,096,741 shares of common stock. At June 30, 2022 there were warrants outstanding to purchase 12,935,323 shares of common stock with an exercise price of $ 2.00 per share. The Company has assessed the warrants for appropriate equity or liability classification and determined the warrants are freestanding instruments that do not meet the definition of a liability pursuant to ASC 480 and do not meet the definition of a derivative pursuant to ASC 815. The warrants are indexed to the Company’s common stock and meet all other conditions for equity classification under ASC 480 and ASC 815. Accordingly, the warrants are classified as equity and accounted for as a component of additional paid-in capital at the time of issuance.

Stock-Based Awards

Stock-Based Awards	6 Months Ended
	Jun. 30, 2022
Share-Based Payment Arrangement [Abstract]
Stock-Based Awards	10 . Stock-Based Awards 2021 Stock Incentive Plan The Company’s 2021 Stock Incentive Plan (the “2021 Plan”) was approved by the Company’s stockholders on June 15, 2021 and became effective on June 16, 2021. Under the 2021 Plan, the Company may grant incentive stock options, nonstatutory stock options, stock appreciation rights, restricted stock awards, awards of restricted stock units and other stock-based awards. The Company’s employees, officers, directors, consultants and advisors are eligible to receive awards under the 2021 Plan; however, incentive stock options may only be granted to employees. The 2021 Plan is administered by the board of directors or, at the discretion of the board of directors, by a committee of the board. The number of shares of common stock covered by options and the date those options become exercisable, type of options to be granted, exercise prices, vesting and other restrictions are determined at the discretion of the board of directors, or its committee if so delegated. Stock options granted under the 2021 Plan with service-based vesting conditions generally vest over four years and may not have a duration in excess of ten years , although options have been granted with vesting terms of less than four years . The total number of shares of common stock that may be issued under the 2021 Plan was 14,185,751 a s of June 30, 2022 , of which 5,937,751 s hares remained available for grant. The Company initially reserved 12,500,000 shares of common stock, plus the number of shares of common stock subject to then outstanding awards under the Company’s 2017 Stock Incentive Plan (the “2017 Plan”), the Company’s 2016 Stock Incentive Plan (“the 2016 Plan”), and the Company’s 2006 Stock Incentive Plan, as amended (the “2006 Plan”) that expire, terminate or are otherwise surrendered, canceled, forfeited or repurchased by the Company at their original issuance price pursuant to a contractual repurchase right up to 6,280,135 shares. Shares that are expired, terminated, surrendered or canceled without having been fully exercised will be available for future awards. In addition, shares of common stock that are tendered to the Company by a participant to exercise an award are added to the number of shares of common stock available for the grant of awards. The exercise price for stock options granted may not be less than the fair market value of the common stock as of the date of grant. 2017 Stock Incentive Plan The 2017 Plan was approved by the Company’s stockholders on June 16, 2017, and became effective on June 28, 2017. Under the 2017 Plan, the Company could grant incentive stock options, nonstatutory stock options, stock appreciation rights, restricted stock awards, awards of restricted stock units and other stock-based awards. The Company’s employees, officers, directors, consultants and advisors were eligible to receive awards under the 2017 Plan; however, incentive stock options could only be granted to employees. The 2017 Plan is administered by the board of directors or, at the discretion of the board of directors, by a committee of the board. The number of shares of common stock covered by options and the date those options become exercisable, type of options granted, exercise prices, vesting and other restrictions were determined at the discretion of the board of directors, or its committee if so delegated. Stock options granted under the 2017 Plan with service-based vesting conditions generally vest over four years and may not have a duration in excess of ten years , although options have been granted with vesting terms of less than four years . The exercise price for stock options granted may not be less than the fair market value of the common stock as of the date of grant. As of the effective date of the 2021 Plan, the board of directors determined to grant no further awards under the 2017 Plan. Shares that are expired, terminated, surrendered or canceled without having been fully exercised will be available for future awards under the 2021 Plan. In addition, shares of common stock that are tendered to the Company by a participant to exercise an award are added to the number of shares of common stock available for the grant of awards under the 2021 Plan. 2017 Employee Stock Purchase Plan On June 16, 2017, the Company’s stockholders approved the 2017 Employee Stock Purchase Plan (the “2017 ESPP”), which became effective on June 28, 2017. A total of 150,000 shares of common stock were initially reserved for issuance under this plan. Under the 2017 ESPP, the number of shares of common stock that may be issued under the 2017 ESPP will automatically increase on each January 1, beginning with the fiscal year ending December 31, 2018 and continuing for each fiscal year until, and including, the fiscal year ending December 31, 2027, equal to the least of (i) 622,408 shares, (ii) 1 % of the outstanding shares of common stock on such date and (iii) an amount determined by the Company’s board of directors. The compensation committee of the board of directors has determined that the number of shares of common stock that may be issued under the 2017 ESPP would no t be increased on January 1, 2021 or January 1, 2022. The Company has no t issued any shares under the 2017 ESPP. Stock Option Valuation The assumptions that the Company used to determine the grant-date fair value of the stock options granted to employees and directors during the six months ended June 30, 2022 and 2021 were as follows, presented on a weighted average basis: Six Months Ended Six Months Ended Risk-free interest rate 2.46 % 0.96 % Expected term (in years) 5.9 6.2 Expected volatility 94.2 % 91.0 % Expected dividend yield 0 % 0 % Stock Options The following table summarizes the Company’s stock option activity since January 1, 2022: Number of Weighted Weighted Aggregate Outstanding at December 31, 2021 9,375,497 $ 1.79 8.5 $ 4 Granted 3,148,500 0.46 Exercised — 0.00 Canceled, forfeited or expired ( 1,401,565 ) 1.02 Outstanding at June 30, 2022 11,122,432 $ 1.51 8.2 $ — Options exercisable at June 30, 2022 5,099,852 $ 2.21 7.0 $ — Options vested and expected to vest at June 30, 2022 10,902,956 $ 2.21 8.1 $ — The weighted average grant-date fair value of stock options granted during the six months ended June 30, 2022 and 2021 was $ 0.35 and $ 0.97 , respectively. The aggregate fair value of stock options that vested during the six months ended June 30, 2022 and 2021 was $ 2,003 and $ 708 , respectively. The aggregate intrinsic value of stock options is calculated as the difference between the exercise price of the stock options and the fair value of the Company’s common stock for those stock options that had exercise prices lower than the fair value of the Company’s common stock. The aggregate intrinsic value of stock options exercised during the six months ended June 30, 2022 and 2021 was $ 0 . Restricted Stock Units The following table summarizes the Company’s restricted stock activity since January 1, 2022: Weighted-Average Number of Grant Date Fair Value Units per Unit Outstanding, non-vested at December 31, 2021 — $ — Issued 250,000 0.39 Vested ( 250,000 ) 0.39 Canceled/forfeited — — Outstanding, non-vested at June 30, 2022 — — Stock-Based Compensation The Company recorded stock-based compensation expense related to stock options and restricted stock units in the following expense categories of its statements of operations and comprehensive loss: Three Months Ended June 30, Six Months Ended June 30, 2022 2021 2022 2021 Research and development expenses $ 178 $ 103 $ 321 $ 202 General and administrative expenses 350 258 896 791 Total Stock Based Compensation $ 528 $ 361 $ 1,217 $ 993 As of June 30, 2022 , the Company had an aggregate of $ 4,050 of unrecognized stock-based compensation expense, which it expects to recognize over a weighted average period of 2.86 years.

Net Loss per Share

Net Loss per Share	6 Months Ended
	Jun. 30, 2022
Earnings Per Share [Abstract]
Net Loss per Share	11 . Net Loss per Share The Company’s potential dilutive securities as of June 30, 2022 and 2021, which include stock options and warrants, have been excluded from the computation of diluted net loss per share whenever the effect of including them would be to reduce the net loss per share. In periods where there is a net loss, the weighted average number of shares of common stock outstanding used to calculate both basic and diluted net loss per share is the same. The following potential shares of common stock, presented based on amounts outstanding at each period end, were excluded from the calculation of diluted net loss per share for the periods indicated because including them would have had an anti-dilutive effect: Six Months Ended June 30, 2022 2021 Warrants to purchase common stock 12,935,323 12,935,323 Stock options to purchase common stock 11,122,432 9,618,672 Total 24,057,755 22,553,995

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2022
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	12 . Commitments and Contingencies Intellectual Property Licenses Harvard and Dana-Farber Agreement In August 2006, the Company entered into an exclusive license agreement with President and Fellows of Harvard College (“Harvard”) and Dana-Farber Cancer Institute (“DFCI”). The agreement granted the Company an exclusive worldwide license, with the right to sublicense, under specified patents and patent applications to develop, obtain regulatory approval for and commercialize specified product candidates based on cell-permeating peptides. Under the agreement, the Company is obligated to use commercially reasonable efforts to develop and commercialize one or more licensed products and to achieve specified milestone events by specified dates. In connection with entering into the agreement, the Company paid an upfront license fee and issued to Harvard and DFCI shares of its common stock. In February 2010, the agreement was amended and restated (the “Harvard/DFCI agreement”) under which additional patent rights were added to the scope of the license agreement and the annual license maintenance fees were increased. Under the Harvard/DFCI agreement, the Company is obligated to make aggregate milestones payments of up to $ 7,700 per licensed therapeutic product upon the Company’s achievement of specified clinical, regulatory and sales milestones with respect to such product and up to $ 700 per licensed diagnostic product upon the Company’s achievement of specified regulatory and sales milestones with respect to such product. In addition, the Company is obligated to pay royalties of low single-digit percentages on annual net sales of licensed products sold by the Company, its affiliates or its sublicensees. The royalties are payable on a product-by-product and country-by-country basis, and may be reduced in specified circumstances. In addition, the agreement obligates the Company to pay a percentage, up to the mid-twenties, of fees received by the Company in connection with its sublicense of the licensed products. In accordance with the terms of the agreement, the Company’s sublicense payment obligations may be subject to specified reductions. The Company has not recorded a liability for the aforementioned payments given the achievement of specified clinical, regulatory and sales milestones is not probable as of June 30, 2022. The Harvard/DFCI agreement requires the Company to pay annual license maintenance fees of $ 110 . Any payments made in connection with the annual license maintenance fees will be credited against any royalties due. The Company incurred license maintenance fees of $ 110 and $ 145 during each of the six months ended June 30, 2022 and 2021 . The Company did no t make any milestone payments during the three and six months ended June 30, 2022 and 2021, respectively. As of June 30, 2022 , no additional milestones had been achieved and no liabilities for additional milestone payments had been recorded in the Company’s accompanying unaudited condensed financial statements. As of June 30, 2022 , the Company had not developed a commercial product using the licensed technologies and no royalties under the agreement had been paid or were due. Under the Harvard/DFCI agreement, the Company is responsible for all patent expenses related to the prosecution and maintenance of the licensed patents and applications in-licensed under the agreement as well as cost reimbursement of amounts incurred for all documented patent-related expenses. The agreement will expire on a product-by-product and country-by-country basis upon the last to expire of any valid patent claim pertaining to licensed products covered under the agreement. Umicore Agreement In December 2006, the Company entered into a license agreement with Materia, Inc. (“Materia”), under which it was granted a non-exclusive worldwide license, with the right to sublicense, under specified patent and patent applications to utilize Materia’s catalysts to develop, obtain regulatory approval for and commercialize specified peptides owned or controlled by Materia and the right to manufacture specified compositions owned or controlled by Materia. In February 2017, Materia assigned the license agreement (the “Umicore agreement”) to Umicore Precious Metals Chemistry USA, LLC (“Umicore”), and Umicore agreed to continue to supply the Company under the agreement. Under the Umicore agreement, the Company is obligated to make aggregate milestone payments to Umicore of up to $ 6,400 upon the Company’s achievement of specified clinical, regulatory and sales milestones with respect to each licensed product. In addition, the Company is obligated to pay tiered royalties ranging in the low single-digit percentages on annual net sales of licensed products sold by the Company or its sublicensees. The royalties are payable on a product-by-product and country-by-country basis and may be reduced in specified circumstances. The Company has not recorded a liability for the aforementioned payments given the achievement of specified regulatory approval and commercial sales milestones is not probable as of June 30, 2022. The Umicore agreement requires the Company to pay annual license fees of $ 50 . The Company incurred license fees of $ 50 during the six months ended June 30, 2022 and 2021 , respectively and did no t make any milestone payments during the same period. As of June 30, 2022 , no additional milestones had been achieved and no liabilities for additional milestone payments had been recorded in the Company’s financial statements. The Umicore agreement expires upon the expiration of the Company’s obligation to pay royalties in each territory covered under the agreement. Indemnification Agreements In the ordinary course of business, the Company may provide indemnification of varying scope and terms to vendors, lessors, business partners and other parties with respect to certain matters including, but not limited to, losses arising out of breach of such agreements or from intellectual property infringement claims made by third parties. In addition, the Company has entered into indemnification agreements with members of its board of directors and officers that will require the Company, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors or officers. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is, in many cases, unlimited. To date, the Company has not incurred any material costs as a result of such indemnifications. The Company is not aware of any claims for indemnification that would have a material effect on its financial position, results of operations or cash flows, and it had not accrued any liabilities related to such obligations in its financial statements as of June 30, 2022 or December 31, 2021 .

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2022
Accounting Policies [Abstract]
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities as of the date of the financial statements and the reported amounts of expenses during the reporting periods. Significant estimates and assumptions reflected in these financial statements include, but are not limited to, the accrual of research and development expenses and the valuation of common stock based on stock-based awards. Estimates are periodically reviewed in light of changes in circumstances, facts and experience. Actual results could differ from the Company's estimates.
Unaudited Interim Financial Information	Unaudited Interim Financial Information The accompanying unaudited condensed financial statements as of June 30, 2022 and for the three and six months ended June 30, 2022 and 2021 have been prepared by the Company pursuant to the rules and regulations of the United States Securities and Exchange Commission (“SEC”) for interim financial statements. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. However, the Company believes that the disclosures are adequate to make the information presented not misleading. These financial statements should be read in conjunction with the Company’s audited financial statements and the notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2021 that was filed with the SEC on March 28, 2022. The unaudited interim condensed financial statements have been prepared on the same basis as the audited financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair statement of the Company’s financial position as of June 30, 2022, the results of its operations for the three and six months ended June 30, 2022 and 2021 and its cash flows for the six months ended June 30, 2022 and 2021. The financial data and other information disclosed in these notes related to the three and six months ended June 30, 2022 and 2021 are unaudited. The results for the six months ended June 30, 2022 are not necessarily indicative of results to be expected for the year ending December 31, 2022, any other interim periods, or any future year or period. The accompanying balance sheet as of December 31, 2021 has been derived from the Company’s audited financial statements for the year ended December 31, 2021 included in the Company’s Annual Report on Form 10-K that was filed with the SEC on March 28, 2022. Our significant accounting policies are described in Note 2 to the financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2021 that was filed with the SEC on March 28, 2022.
Concentration of Credit Risk and of Significant Suppliers	Concentration of Credit Risk and of Significant Suppliers Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash, cash equivalents and investments. From time to time, the Company has maintained all of its cash, cash equivalents and investment balances at three accredited financial institutions, in amounts that exceed federally insured limits. The Company generally invests its excess cash in money market funds, commercial paper and corporate notes that are subject to minimal credit and market risks. Management has established guidelines relative to credit ratings and maturities intended to safeguard principal balances and maintain liquidity. The investment portfolio is maintained in accordance with the Company’s investment policy, which defines allowable investments, specifies credit quality standards and limits the credit exposure of any single issuer. The Company is dependent on third-party manufacturers to supply products for research and development activities of its programs, including preclinical and clinical testing. In particular, the Company relies and expects to continue to rely on a small number of manufacturers to supply it with its requirements for the active pharmaceutical ingredients and formulated drugs related to these programs. These programs could be adversely affected by a significant interruption in the supply of active pharmaceutical ingredients and formulated drugs.
Risks and Uncertainties	Risks and Uncertainties The ongoing COVID-19 pandemic and government measures taken in response have had a significant impact, both direct and indirect, on businesses and commerce. The future progression of the pandemic and its effects on our business and operations are uncertain. Potential impacts to the Company’s business include disruptions in supply of the Company’s product candidate and/or procurement of items that are essential for the Company’s research and development activities, including, for example, raw materials used in the manufacturing of ALRN-6924, medical and laboratory supplies used in the Company’s clinical trials or preclinical studies or animals that are used for preclinical testing, in each case, for which there may be shortages because of ongoing efforts to address the COVID-19 pandemic. While the Company believes that it currently has sufficient supply of its product candidate to conduct the Company’s Phase 1b clinical trial in breast cancer, its product candidate, or materials contained therein, come from facilities located in areas impacted by the COVID-19 pandemic. Additionally, the Company has enrolled, and is seeking to enroll, cancer patients in the Company’s clinical trials at sites located both in the United States and Europe, which are areas that continue to be impacted by the COVID-19 pandemic. Enrollment at clinical trial sites has been and may continue to be disrupted as the effects of the COVID-19 pandemic persist. In the event that clinical trial sites close to enrollment in the Company’s trials or shift resources to address COVID-19, this could have a material adverse impact on the Company’s clinical trial plans and timelines. The Company may face difficulties recruiting or retaining patients in its clinical trials if patients are affected by the virus or are fearful of visiting or traveling to the Company’s clinical trial sites because of the COVID-19 pandemic. Any negative impact that the COVID-19 outbreak has on the ability of the Company’s suppliers to provide materials necessary for the Company’s product candidate or on recruiting or retaining patients in the Company’s clinical trials could cause costly delays to clinical trial activities, which could adversely affect the Company’s ability to obtain regulatory approval for and to commercialize the Company’s product candidate, increase the Company’s operating expenses, affect the Company’s ability to raise additional capital, and impact the Company’s operating and financial results. The capital markets have also experienced significant volatility as a result of the pandemic. Future disruptions in the capital markets could negatively impact the Company’s ability to raise capital in the future.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements In June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses (ASU 2016-13 or Topic 326): Measurement of Credit Losses on Financial Instruments, which requires the measurement and recognition of expected credit losses for financial assets held at amortized cost. ASU 2016-13 replaces the existing incurred loss impairment model with an expected loss methodology, which will result in more timely recognition of credit losses. The ASU will be effective for the Company's fiscal year beginning January 1, 2023. The Company is currently evaluating the impact of the adoption of ASU 2016-13 and does not expect adoption to have a material effect on the Company’s consolidated financial statements or disclosures. Other accounting standards that have been issued or proposed by the FASB or other standards-setting bodies that do not require adoption until a future date are not expected to have a material impact on the Company’s financial statements upon adoption.

Fair Value of Financial Assets

Fair Value of Financial Assets (Tables)	6 Months Ended
	Jun. 30, 2022
Fair Value Disclosures [Abstract]
Summary of Assets Measured at Fair Value on Recurring Basis	The following tables present information about the Company’s assets that are measured at fair value on a recurring basis and indicate the level of the fair value hierarchy utilized to determine such fair values: Fair Value Measurements as of Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 4,144 $ — $ — $ 4,144 Investments: Commercial paper — 16,805 — 16,805 Corporate notes — 1,250 — 1,250 Treasury bills — 6,699 — 6,699 Total Fair Value of Financial Instruments as of June 30, 2022 $ 4,144 $ 24,754 $ — $ 28,898 Fair Value Measurements as of Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 2,438 $ — $ — $ 2,438 Investments: Commercial paper — 33,969 — 33,969 Corporate notes — 6,366 — 6,366 Treasury Bills — 1,998 — 1,998 Total Fair Value of Financial Instruments as of December 31, 2021 $ 2,438 $ 42,333 $ — $ 44,771

Investments (Tables)

Investments (Tables)	6 Months Ended
	Jun. 30, 2022
Investments, Debt and Equity Securities [Abstract]
Summary of Fair Value of Available for Sale Investments	As of June 30, 2022 and December 31, 2021, the fair value of available-for-sale investments by type of security was as follows: June 30, 2022 Amortized Gross Gross Fair Investments: Commercial paper $ 16,852 $ — $ ( 47 ) $ 16,805 Corporate notes 1,258 — ( 8 ) 1,250 Treasury Bills 6,745 — ( 46 ) 6,699 Total Investments as of June 30, 2022 $ 24,855 $ — $ ( 101 ) $ 24,754 December 31, 2021 Amortized Gross Gross Fair Investments: Commercial paper $ 33,976 $ — $ ( 7 ) $ 33,969 Corporate notes 6,368 — ( 2 ) 6,366 Treasury bills 2,002 — ( 4 ) 1,998 Total Investments as of December 31, 2021 $ 42,346 $ — $ ( 13 ) $ 42,333

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	6 Months Ended
	Jun. 30, 2022
Property, Plant and Equipment [Abstract]
Summary of Property and Equipment, Net	Property and equipment, net consisted of the following: June 30, December 31, Computer equipment and software $ 338 $ 340 Less: Accumulated depreciation and amortization ( 240 ) ( 212 ) Total Property and Equipment, Net $ 98 $ 128

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	6 Months Ended
	Jun. 30, 2022
Payables and Accruals [Abstract]
Summary of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consisted of the following: June 30, December 31, External research and development services $ 1,664 $ 1,575 Payroll and payroll-related costs 702 1,182 Professional fees 859 388 Other 85 60 Total Accrued Expenses and Other Liabilities $ 3,310 $ 3,205

Stock-Based Awards (Tables)

Stock-Based Awards (Tables)	6 Months Ended
	Jun. 30, 2022
Share-Based Payment Arrangement [Abstract]
Valuation Assumptions of Stock Options Granted	The assumptions that the Company used to determine the grant-date fair value of the stock options granted to employees and directors during the six months ended June 30, 2022 and 2021 were as follows, presented on a weighted average basis: Six Months Ended Six Months Ended Risk-free interest rate 2.46 % 0.96 % Expected term (in years) 5.9 6.2 Expected volatility 94.2 % 91.0 % Expected dividend yield 0 % 0 %
Summary of Stock Option Activity	The following table summarizes the Company’s stock option activity since January 1, 2022: Number of Weighted Weighted Aggregate Outstanding at December 31, 2021 9,375,497 $ 1.79 8.5 $ 4 Granted 3,148,500 0.46 Exercised — 0.00 Canceled, forfeited or expired ( 1,401,565 ) 1.02 Outstanding at June 30, 2022 11,122,432 $ 1.51 8.2 $ — Options exercisable at June 30, 2022 5,099,852 $ 2.21 7.0 $ — Options vested and expected to vest at June 30, 2022 10,902,956 $ 2.21 8.1 $ —
Summary of Restricted Stock Unit Activity	The following table summarizes the Company’s restricted stock activity since January 1, 2022: Weighted-Average Number of Grant Date Fair Value Units per Unit Outstanding, non-vested at December 31, 2021 — $ — Issued 250,000 0.39 Vested ( 250,000 ) 0.39 Canceled/forfeited — — Outstanding, non-vested at June 30, 2022 — —
Summary of Stock Based Compensation Expense	The Company recorded stock-based compensation expense related to stock options and restricted stock units in the following expense categories of its statements of operations and comprehensive loss: Three Months Ended June 30, Six Months Ended June 30, 2022 2021 2022 2021 Research and development expenses $ 178 $ 103 $ 321 $ 202 General and administrative expenses 350 258 896 791 Total Stock Based Compensation $ 528 $ 361 $ 1,217 $ 993

Net Loss per Share (Tables)

Net Loss per Share (Tables)	6 Months Ended
	Jun. 30, 2022
Earnings Per Share [Abstract]
Summary of Potential Common Shares Excluded from Calculation of Diluted Net Loss per Share	The following potential shares of common stock, presented based on amounts outstanding at each period end, were excluded from the calculation of diluted net loss per share for the periods indicated because including them would have had an anti-dilutive effect: Six Months Ended June 30, 2022 2021 Warrants to purchase common stock 12,935,323 12,935,323 Stock options to purchase common stock 11,122,432 9,618,672 Total 24,057,755 22,553,995

Nature of the Business and Ba_2

Nature of the Business and Basis of Presentation - Additional Information (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Class of Stock [Line Items]
Proceeds from collaboration agreement	$ 34,910
Cash, cash equivalents and investments	32,382
Accumulated deficit	(261,870)	$ (245,456)
Common Stock [Member]
Class of Stock [Line Items]
Proceeds from sales of stock	145,467
Preferred Stock [Member]
Class of Stock [Line Items]
Proceeds from sales of stock	$ 131,211

Fair Value of Financial Asset_2

Fair Value of Financial Assets - Summary of Assets Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments	$ 24,754	$ 42,333
Commercial Paper [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments	16,805	33,969
Corporate Notes [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments	1,250	6,366
Treasury Bills [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments	6,699	1,998
Recurring [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total Fair Value of Financial Instruments	28,898	44,771
Recurring [Member] | Level 1 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total Fair Value of Financial Instruments	4,144	2,438
Recurring [Member] | Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total Fair Value of Financial Instruments	24,754	42,333
Recurring [Member] | Commercial Paper [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments	16,805	33,969
Recurring [Member] | Commercial Paper [Member] | Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments	16,805	33,969
Recurring [Member] | Corporate Notes [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments	1,250	6,366
Recurring [Member] | Corporate Notes [Member] | Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments	1,250	6,366
Recurring [Member] | Treasury Bills [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments	6,699	1,998
Recurring [Member] | Treasury Bills [Member] | Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Investments	6,699	1,998
Recurring [Member] | Money Market Funds [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents	4,144	2,438
Recurring [Member] | Money Market Funds [Member] | Level 1 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents	$ 4,144	$ 2,438

Fair Value of Financial Asset_3

Fair Value of Financial Assets - Additional Information (Detail) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Available-for-sale investments, maximum contractual maturity period	1 year
Fair Value, assets transfers into (out of) Level 3	$ 0	$ 0

Investments - Summary of Fair V

Investments - Summary of Fair Value of Available for Sale Investments (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Schedule of Available-for-sale Securities [Line Items]
Investments, Amortized Cost	$ 24,855	$ 42,346
Investments, Gross Unrealized Loss	(101)	(13)
Investments, Fair Value	24,754	42,333
Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Amortized Cost	16,852	33,976
Investments, Gross Unrealized Loss	(47)	(7)
Investments, Fair Value	16,805	33,969
Corporate Notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Amortized Cost	1,258	6,368
Investments, Gross Unrealized Loss	(8)	(2)
Investments, Fair Value	1,250	6,366
Treasury Bills [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Amortized Cost	6,745	2,002
Investments, Gross Unrealized Loss	(46)	(4)
Investments, Fair Value	$ 6,699	$ 1,998

Property and Equipment, Net - S

Property and Equipment, Net - Summary of Property and Equipment, Net (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Property Plant And Equipment [Line Items]
Less: Accumulated depreciation and amortization	$ (240)	$ (212)
Total Property and Equipment, Net	98	128
Computer Equipment and Software [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 338	$ 340

Property and Equipment, Net - A

Property and Equipment, Net - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Sep. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Property Plant And Equipment [Line Items]
Depreciation and amortization expense		$ 29	$ 15
Fully Depreciated Assets [Member]
Property Plant And Equipment [Line Items]
Gain (loss) on disposal of property and equipment	$ 66

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities - Summary of Accrued Expenses and Other Current Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Payables and Accruals [Abstract]
External research and development services	$ 1,664	$ 1,575
Payroll and payroll-related costs	702	1,182
Professional fees	859	388
Other	85	60
Total Accrued Expenses and Other Liabilities	$ 3,310	$ 3,205

Paycheck Protection Loan - Addi

Paycheck Protection Loan - Additional Information (Detail) - Paycheck Protection Program CARES Act [Member] $ in Thousands		6 Months Ended
	Apr. 30, 2020 USD ($)	Jun. 30, 2022
Debt Instrument [Line Items]
Proceeds from loan	$ 384
Number of times for loans to qualifying businesses average monthly payroll costs	2.5
Term of unforgiven portion of loan	2 years
Interest rate	1%
Term of deferral payments	6 months
Debt instrument, description		The PPP, established as part of the Coronavirus Aid, Relief and Economic Security Act (“CARES Act”), provides for loans to qualifying businesses for amounts up to 2.5 times the average monthly payroll expenses of the qualifying business. The loan and accrued interest are forgivable after eight weeks if the borrower uses the loan proceeds for eligible purposes, including payroll, benefits, rent and utilities. The amount of loan forgiveness may be reduced if the borrower terminates employees or reduces salaries during the eight-week period. The unforgiven portion of the PPP loan is payable over two years at an interest rate of 1%, with a deferral of payments for the first six months. The Company used the proceeds for purposes consistent with the PPP.
Minimum [Member]
Debt Instrument [Line Items]
Term of loan and accrued interest forgivable	56 days

Lease - Additional Information

Lease - Additional Information (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2022 USD ($)	Dec. 31, 2021 USD ($)	Mar. 26, 2021 ft²
Lessee Lease Description [Line Items]
Operating lease, right-of-use asset	$ 98	$ 152
Sublease [Member]
Lessee Lease Description [Line Items]
Lease commencement date	Apr. 01, 2021
Lease termination date	Mar. 31, 2023
Amount of obligated to pay monthly base rent to sub lessor during the term	$ 12
Operating lease, right-of-use asset	228
Operating lease, liability	$ 217
Sublease [Member] | Boston, Massachusetts [Member]
Lessee Lease Description [Line Items]
Area of land | ft²			3,365

Common Stock - Additional Infor

Common Stock - Additional Information (Detail) - USD ($)				1 Months Ended		3 Months Ended	6 Months Ended	12 Months Ended
	Jan. 29, 2021	Jan. 06, 2021	Apr. 02, 2019	Jan. 28, 2021	Jul. 31, 2019	Mar. 31, 2021	Jun. 30, 2022	Dec. 31, 2021	Jun. 21, 2022	Dec. 31, 2020
Class of Stock [Line Items]
Common stock, shares authorized							300,000,000	300,000,000		150,000,000
Common stock, par value							$ 0.001	$ 0.001		$ 0.001
Common stock, dividends declared							$ 0	$ 0
Stock issued during period, value						$ 59,088,000
Common and Pre-funded Warrants [Member]
Class of Stock [Line Items]
Aggregate number of common stock shares issued and sold			1,096,741
Pre-funded Warrants [Member]
Class of Stock [Line Items]
Aggregate number of common stock shares issued and sold			1,096,741
Warrants outstanding exercised					1,096,741
Warrants exercise price			$ 0.01
Common Stock [Member]
Class of Stock [Line Items]
Gross proceeds from common stock shares issued and sold							$ 145,467,000
Stock issued during period, value						$ 46,000
Common Warrants [Member]
Class of Stock [Line Items]
Aggregate number of common stock shares issued and sold			1,096,741
Warrants outstanding							12,935,323
Warrants exercise price							$ 2
Common Warrants [Member] | Common and Pre-funded Warrants [Member]
Class of Stock [Line Items]
Purchase price per share			$ 2.01
Private Placement [Member]
Class of Stock [Line Items]
Aggregate number of common stock shares issued and sold			11,838,582
Private Placement [Member] | Common Stock [Member]
Class of Stock [Line Items]
Aggregate number of common stock shares issued and sold			11,838,582
Private Placement [Member] | Common Warrants [Member]
Class of Stock [Line Items]
Aggregate number of common stock shares issued and sold			11,838,582
Purchase price per share			$ 2.01
Securities Purchase Agreement [Member] | Direct Public Offering [Member]
Class of Stock [Line Items]
Common stock, par value		$ 0.001
Aggregate number of common stock shares issued and sold		32,630,983
Expenses fees payable		$ 2,887,000
Gross proceeds from common stock shares issued and sold		$ 35,894,000
Securities Purchase Agreement [Member] | Direct Public Offering [Member] | Common Stock [Member]
Class of Stock [Line Items]
Purchase price per share		$ 1.10
Offering closed date		Jan. 08, 2021
Sales Agreement [Member] | Jones Trading Institutional Services LLC [Member]
Class of Stock [Line Items]
Aggregate number of common stock shares issued and sold				7,174,993
Expenses fees payable				$ 290,000
Gross proceeds from common stock shares issued and sold				$ 9,658,000
ATM Sales Agreement [Member]
Class of Stock [Line Items]
Aggregate number of common stock shares issued and sold							0	5,225,406
Common stock offering price									$ 14,024,100,000
Expenses fees payable								$ 329,000
Gross proceeds from common stock shares issued and sold								$ 10,922,000
ATM Sales Agreement [Member] | Jones Trading Institutional Services LLC and William Blair & Company, LLC [Member] | Maximum [Member]
Class of Stock [Line Items]
Stock issued during period, value	$ 30,000,000
Purchase Agreement [Member] | Jones Trading Institutional Services LLC [Member]
Class of Stock [Line Items]
Aggregate number of common stock shares issued and sold							0	1,375,000
Gross proceeds from common stock shares issued and sold								$ 2,614,000

Stock-Based Awards - Additional

Stock-Based Awards - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands				6 Months Ended
	Jan. 01, 2022	Jan. 01, 2021	Jun. 16, 2017	Jun. 30, 2022	Jun. 30, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average grant-date fair value of stock options				$ 0.35	$ 0.97
Aggregate fair value of stock options vested				$ 2,003	$ 708
Aggregate intrinsic value of stock options exercised				0	$ 0
Aggregate unrecognized stock-based compensation expense				$ 4,050
Unrecognized stock-based compensation expense, weighted average period expects for recognition				2 years 10 months 9 days
2021 Stock Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option granted vesting period				4 years
Number of shares, available for grant				14,185,751
Number of shares remained available for grant				5,937,751
2021 Stock Incentive Plan [Member] | Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option granted vesting period				4 years
Stock option expiration period				10 years
2017 Stock Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option granted vesting period				4 years
Stock reserved for future issuance				12,500,000
2017 Stock Incentive Plan [Member] | Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option granted vesting period				4 years
Stock option expiration period				10 years
2006 Stock Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Contractual repurchase right, shares				6,280,135
2017 Employee Stock Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, available for grant				0
Stock reserved for future issuance			150,000
Maximum annual increase in common stock reserved for future issuance			622,408
Percentage of common stock shares outstanding			1%
Increase to shares authorized for issuance	0	0
Stock incentive plan description				On June 16, 2017, the Company’s stockholders approved the 2017 Employee Stock Purchase Plan (the “2017 ESPP”), which became effective on June 28, 2017. A total of 150,000 shares of common stock were initially reserved for issuance under this plan. Under the 2017 ESPP, the number of shares of common stock that may be issued under the 2017 ESPP will automatically increase on each January 1, beginning with the fiscal year ending December 31, 2018 and continuing for each fiscal year until, and including, the fiscal year ending December 31, 2027, equal to the least of (i) 622,408 shares, (ii) 1% of the outstanding shares of common stock on such date and (iii) an amount determined by the Company’s board of directors. The compensation committee of the board of directors has determined that the number of shares of common stock that may be issued under the 2017 ESPP would not be increased on January 1, 2021 or January 1, 2022. The Company has not issued any shares under the 2017 ESPP.

Stock-Based Awards - Valuation

Stock-Based Awards - Valuation Assumptions of Stock Options Granted (Detail)	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Share-Based Payment Arrangement [Abstract]
Risk-free interest rate	2.46%	0.96%
Expected term (in years)	5 years 10 months 24 days	6 years 2 months 12 days
Expected volatility	94.20%	91%
Expected dividend yield	0%	0%

Stock-Based Awards - Summary of

Stock-Based Awards - Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Share-Based Payment Arrangement [Abstract]
Number of Options, Beginning balance	9,375,497
Number of Options, Granted	3,148,500
Number of Options, Exercised	0
Number of Options, Canceled, forfeited or expired	(1,401,565)
Number of Options, Ending balance	11,122,432	9,375,497
Number of Options, Options exercisable	5,099,852
Number of Options, Options vested and expected to vest	10,902,956
Weighted Average Exercise Price, Beginning balance	$ 1.79
Weighted Average Exercise Price, Granted	0.46
Weighted Average Exercise Price, Exercised	0
Weighted Average Exercise Price, Canceled, forfeited or expired	1.02
Weighted Average Exercise Price, Ending balance	1.51	$ 1.79
Weighted Average Exercise Price, Options exercisable	2.21
Weighted Average Exercise Price, Options vested and expected to vest	$ 2.21
Weighted-Average Remaining Term, Outstanding	8 years 2 months 12 days	8 years 6 months
Weighted Average Remaining Term, Options exercisable	7 years
Weighted Average Remaining Term, Options vested and expected to vest	8 years 1 month 6 days
Aggregate Intrinsic Value		$ 4

Stock-Based Awards - Summary _2

Stock-Based Awards - Summary of Restricted Stock Unit Activity (Detail) - 2017 Stock Incentive Plan [Member] - Restricted Stock Units [Member]	6 Months Ended
	Jun. 30, 2022 $ / shares shares
Units
Issued | shares	250,000
Vested | shares	(250,000)
Weighted-Average Grant Date Fair Value per Unit
Issued | $ / shares	$ 0.39
Vested | $ / shares	$ 0.39

Stock-Based Awards - Summary _3

Stock-Based Awards - Summary of Stock Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total Stock Based Compensation	$ 528	$ 361	$ 1,217	$ 993
Research and Development [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total Stock Based Compensation	178	103	321	202
General and Administrative [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total Stock Based Compensation	$ 350	$ 258	$ 896	$ 791

Net Loss per Share - Summary of

Net Loss per Share - Summary of Potential Common Shares Excluded from Calculation of Diluted Net Loss per Share (Detail) - shares	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential common shares excluded from calculation of diluted net loss per share	24,057,755	22,553,995
Warrants to Purchase Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential common shares excluded from calculation of diluted net loss per share	12,935,323	12,935,323
Stock Options to Purchase Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential common shares excluded from calculation of diluted net loss per share	11,122,432	9,618,672

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail)	3 Months Ended		6 Months Ended
	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2022 USD ($) Milestone	Jun. 30, 2021 USD ($)	Feb. 28, 2010 USD ($)	Dec. 31, 2006 USD ($)
Harvard and Dana-Farber Agreement [Member]
Other Commitments [Line Items]
Milestone payments	$ 0	$ 0	$ 0	$ 0
Additional milestones achieved | Milestone			0
Additional liabilities for milestone payments	0		$ 0
Payments for royalties			0
Harvard and Dana-Farber Agreement [Member] | Therapeutic Product [Member]
Other Commitments [Line Items]
Aggregate milestones payments					$ 7,700,000
Harvard and Dana-Farber Agreement [Member] | Diagnostic Product [Member]
Other Commitments [Line Items]
Aggregate milestones payments					$ 700,000
Harvard and Dana-Farber Agreement [Member] | License [Member]
Other Commitments [Line Items]
Annual license maintenance fees			110,000	145,000
Harvard and Dana-Farber Agreement [Member] | License and Maintenance [Member]
Other Commitments [Line Items]
Annual license maintenance fees			110,000
Umicore Agreement [Member]
Other Commitments [Line Items]
Aggregate milestones payments						$ 6,400,000
Milestone payments			$ 0	0
Additional milestones achieved | Milestone			0
Additional liabilities for milestone payments	$ 0		$ 0
Umicore Agreement [Member] | License [Member]
Other Commitments [Line Items]
Annual license maintenance fees			50,000	$ 50,000
Umicore Agreement [Member] | License and Maintenance [Member]
Other Commitments [Line Items]
Annual license maintenance fees			$ 50,000