Kura Oncology (KURA) 10-Q 3 Nov 22 2022 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2022	Oct. 27, 2022
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q3
Trading Symbol	KURA
Entity Registrant Name	KURA ONCOLOGY, INC.
Entity Central Index Key	0001422143
Entity Current Reporting Status	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Shell Company	false
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		66,896,972
Entity File Number	001-37620
Entity Tax Identification Number	61-1547851
Entity Address, Address Line One	12730 High Bluff Drive
Entity Address, Address Line Two	Suite 400
Entity Address, City or Town	San Diego
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92130
City Area Code	858
Local Phone Number	500-8800
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Security Exchange Name	NASDAQ
Entity Incorporation, State or Country Code	DE
Document Quarterly Report	true
Document Transition Report	false

Condensed Balance Sheets (Unaud

Condensed Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 90,937	$ 90,672
Short-term investments	336,838	427,288
Prepaid expenses and other current assets	8,616	4,329
Total current assets	436,391	522,289
Property and equipment, net	2,734	2,673
Restricted cash	210	210
Operating lease right-of-use assets	4,284	5,573
Other long-term assets	4,369	3,306
Total assets	447,988	534,051
Current liabilities:
Accounts payable and accrued expenses	22,441	20,192
Current operating lease liabilities	2,304	2,263
Total current liabilities	24,745	22,455
Long-term operating lease liabilities	3,080	4,612
Other long-term liabilities	542	375
Total liabilities	28,367	27,442
Stockholders' equity:
Preferred stock, $0.0001 par value; 10,000 shares authorized; no shares issued and outstanding
Common stock, $0.0001 par value; 200,000 shares authorized; 66,894 and 66,572 shares issued and outstanding as of September 30, 2022 and December 31, 2021, respectively	7	7
Additional paid-in capital	964,724	941,359
Accumulated other comprehensive loss	(9,416)	(1,789)
Accumulated deficit	(535,694)	(432,968)
Total stockholders' equity	419,621	506,609
Total liabilities and stockholders' equity	$ 447,988	$ 534,051

Condensed Balance Sheets (Una_2

Condensed Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Sep. 30, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	66,894,000	66,572,000
Common stock, shares outstanding	66,894,000	66,572,000

Condensed Statements of Operati

Condensed Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Operating Expenses:
Research and development	$ 24,973	$ 22,367	$ 70,144	$ 63,765
General and administrative	11,621	11,310	34,565	34,455
Total operating expenses	36,594	33,677	104,709	98,220
Other Income (Expense):
Interest and other income, net	1,090	311	1,983	911
Interest expense				(414)
Total other income, net	1,090	311	1,983	497
Net Loss	$ (35,504)	$ (33,366)	$ (102,726)	$ (97,723)
Net loss per share, basic	$ (0.53)	$ (0.50)	$ (1.54)	$ (1.47)
Net loss per share, diluted	$ (0.53)	$ (0.50)	$ (1.54)	$ (1.47)
Weighted average number of shares used in computing net loss per share, basic	66,889	66,353	66,723	66,285
Weighted average number of shares used in computing net loss per share, diluted	66,889	66,353	66,723	66,285
Comprehensive Loss:
Net loss	$ (35,504)	$ (33,366)	$ (102,726)	$ (97,723)
Other comprehensive income (loss):
Unrealized gain (loss) on marketable securities and foreign currency	(1,601)	199	(7,627)	(240)
Comprehensive Loss	$ (37,105)	$ (33,167)	$ (110,353)	$ (97,963)

Condensed Statements of Stockho

Condensed Statements of Stockholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid- In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning balance at Dec. 31, 2020	$ 610,905	$ 7	$ 913,354	$ 46	$ (302,502)
Beginning balance (in shares) at Dec. 31, 2020		66,194
Share-based compensation expense	17,182		17,182
Issuance of common stock under equity plans	3,632		3,632
Issuance of common stock under equity plans, shares		310
Other comprehensive income (loss)	(240)			(240)
Net loss	(97,723)				(97,723)
Ending balance at Sep. 30, 2021	533,756	$ 7	934,168	(194)	(400,225)
Ending balance (in shares) at Sep. 30, 2021		66,504
Beginning balance at Jun. 30, 2021	558,551	$ 7	925,796	(393)	(366,859)
Beginning balance (in shares) at Jun. 30, 2021		66,296
Share-based compensation expense	6,114		6,114
Issuance of common stock under equity plans	2,258		2,258
Issuance of common stock under equity plans, shares		208
Other comprehensive income (loss)	199			199
Net loss	(33,366)				(33,366)
Ending balance at Sep. 30, 2021	533,756	$ 7	934,168	(194)	(400,225)
Ending balance (in shares) at Sep. 30, 2021		66,504
Beginning balance at Dec. 31, 2021	506,609	$ 7	941,359	(1,789)	(432,968)
Beginning balance (in shares) at Dec. 31, 2021		66,572
Share-based compensation expense	19,513		19,513
Issuance of common stock under equity plans	3,852		3,852
Issuance of common stock under equity plans, shares		322
Other comprehensive income (loss)	(7,627)			(7,627)
Net loss	(102,726)				(102,726)
Ending balance at Sep. 30, 2022	419,621	$ 7	964,724	(9,416)	(535,694)
Ending balance (in shares) at Sep. 30, 2022		66,894
Beginning balance at Jun. 30, 2022	449,491	$ 7	957,489	(7,815)	(500,190)
Beginning balance (in shares) at Jun. 30, 2022		66,838
Share-based compensation expense	6,355		6,355
Issuance of common stock under equity plans	880		880
Issuance of common stock under equity plans, shares		56
Other comprehensive income (loss)	(1,601)			(1,601)
Net loss	(35,504)				(35,504)
Ending balance at Sep. 30, 2022	$ 419,621	$ 7	$ 964,724	$ (9,416)	$ (535,694)
Ending balance (in shares) at Sep. 30, 2022		66,894

Condensed Statements of Cash Fl

Condensed Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Operating Activities
Net loss	$ (102,726)	$ (97,723)
Adjustments to reconcile net loss to net cash used in operating activities:
Share-based compensation expense	19,513	17,182
Amortization of premium and accretion of discounts on marketable securities, net	2,264	3,175
Depreciation expense	553	392
Non-cash interest expense		399
Loss on extinguishment of debt		212
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(4,287)	(1,488)
Other long-term assets	226	(746)
Accounts payable and accrued expenses	758	(2,549)
Other long-term liabilities	167	(39)
Net cash used in operating activities	(83,532)	(81,185)
Investing Activities
Maturities of marketable securities	245,091	229,469
Purchases of marketable securities	(164,532)	(429,320)
Purchases of property and equipment	(614)	(1,045)
Net cash provided by (used in) investing activities	79,945	(200,896)
Financing Activities
Proceeds from issuance of stock under equity plans	3,852	3,632
Repayment of long-term debt		(7,250)
Payment of fees related to extinguishment of debt		(611)
Net cash provided by (used in) financing activities	3,852	(4,229)
Net increase (decrease) in cash, cash equivalents and restricted cash	265	(286,310)
Cash, cash equivalents and restricted cash at beginning of period	90,882	325,703
Cash, cash equivalents and restricted cash at end of period	$ 91,147	$ 39,393

Organization and Basis of Prese

Organization and Basis of Presentation	9 Months Ended
	Sep. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Basis of Presentation	1. Organization and Basis of Presentation The Company Kura Oncology, Inc. is a clinical-stage biopharmaceutical company committed to realizing the promise of precision medicines for the treatment of cancer. Our pipeline consists of small molecule product candidates that target cancer signaling pathways where there is a strong scientific and clinical rationale to improve outcomes, and we intend to pair them with molecular or cellular diagnostics to identify those patients most likely to respond to treatment. We plan to advance our product candidates through a combination of internal development and strategic partnerships while maintaining significant development and commercial rights. References in these Notes to Unaudited Condensed Financial Statements to the “Company,” “we,” “our” or “us,” refer to Kura Oncology, Inc. Basis of Presentation The accompanying unaudited condensed financial statements should be read in conjunction with the audited financial statements and notes thereto in our Annual Report on Form 10-K for the fiscal year ended December 31, 2021, as filed with the Securities and Exchange Commission on February 24, 2022, from which we derived our balance sheet as of December 31, 2021. The accompanying unaudited condensed financial statements have been prepared in accordance with U.S. generally accepted accounting principles, or GAAP, for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, since they are interim statements, the accompanying unaudited condensed financial statements do not include all of the information and notes required by GAAP for complete financial statements. The accompanying unaudited condensed financial statements reflect all adjustments, consisting of normal recurring adjustments, that are, in the opinion of our management, necessary to a fair statement of the results for the interim periods presented. Interim results are not necessarily indicative of results for a full year. The preparation of the unaudited condensed financial statements in accordance with GAAP requires our management to make estimates and assumptions that affect the amounts reported on our unaudited condensed financial statements and accompanying notes. The amounts reported could differ under different estimates and assumptions. On an ongoing basis, we evaluate our estimates and judgments, which are based on historical and anticipated results and trends and on various other assumptions that management believes to be reasonable under the circumstances. Though the impact of the COVID-19 pandemic to our business and operating results presents additional uncertainty, we continue to use the best information available to inform our critical accounting estimates. By their nature, estimates are subject to an inherent degree of uncertainty and, as such, actual results may differ from management’s estimates. The extent to which the COVID-19 pandemic has impacted and may continue to impact our business will depend on future developments, which are highly uncertain and cannot be predicted with any confidence, such as the duration and severity of the COVID-19 pandemic, steps required or mandated by governments to mitigate the impact of COVID-19 or the effectiveness of actions to prevent, contain and treat COVID-19, particularly in the geographies where we, our third-party manufacturers, contract research organizations or current and planned clinical trial sites operate. We cannot presently predict the scope and severity of any potential business disruptions, interruptions or shutdowns. If we or any of the third parties with whom we engage, however, were to experience shutdowns or other business disruptions, our ability to conduct our business in the manner and on the timelines presently planned could be materially and negatively affected, which could have a material adverse impact on our business and our results of operations and financial condition.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2022
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Reclassifications Certain prior period balances have been reclassified to conform to the current period presentation. Restricted Cash Under the terms of an office lease entered into in March 2020, we are required to maintain a standby letter of credit during the term of the lease. As of September 30, 2022 , restricted cash of $ 0.2 million was pledged as collateral for the letter of credit. The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the unaudited condensed balance sheets that sum to the total of the amounts shown in the unaudited condensed statements of cash flows, in thousands: September 30, 2022 December 31, 2021 September 30, 2021 December 31, 2020 Cash and cash equivalents $ 90,937 $ 90,672 $ 39,183 $ 325,493 Restricted cash 210 210 210 210 Total $ 91,147 $ 90,882 $ 39,393 $ 325,703 Allowance for Credit Losses For available-for-sale securities in an unrealized loss position, we first assess whether we intend to sell, or if it is more likely than not that we will be required to sell, the security before recovery of its amortized cost basis. If either of the criteria regarding intent or requirement to sell is met, the security’s amortized cost basis is written down to fair value through earnings. For available-for-sale securities that do not meet the aforementioned criteria, we evaluate whether the decline in fair value has resulted from credit losses or other factors. In making this assessment, we consider the severity of the impairment, any changes in interest rates, market conditions, changes to the underlying credit ratings and forecasted recovery, among other factors. The credit-related portion of unrealized losses, and any subsequent improvements, are recorded in interest income through an allowance account. Any impairment that has not been recorded through an allowance for credit losses is included in other comprehensive income (loss) on the unaudited condensed statements of operations and comprehensive loss. We elected the practical expedient to exclude the applicable accrued interest from both the fair value and amortized costs basis of our available-for-sale securities for purposes of identifying and measuring an impairment. Accrued interest receivable on available-for-sale securities is recorded within prepaid expenses and other current assets on our unaudited condensed balance sheets. Our accounting policy is to not measure an allowance for credit loss for accrued interest receivable and to write-off any uncollectible accrued interest receivable as a reversal of interest income in a timely manner, which we consider to be in the period in which we determine the accrued interest will not be collected by us. Concentration of Credit Risk Financial instruments that potentially subject us to significant concentrations of credit risk consist primarily of cash, cash equivalents and short-term investments. We maintain deposits in federally insured financial institutions in excess of federally insured limits. We have established guidelines to limit our exposure to credit risk by placing investments with high credit quality financial institutions, diversifying our investment portfolio and placing investments with maturities that maintain safety and liquidity. We periodically review and modify these guidelines to maximize trends in yields and interest rates without compromising safety and liquidity. Net Loss per Share Basic net loss per common share is calculated by dividing the net loss by the weighted-average number of common shares outstanding for the period, without consideration for common stock equivalents. Diluted net loss per share is calculated by dividing the net loss by the weighted-average number of common shares and common stock equivalents outstanding for the period determined using the treasury-stock method. As we have reported net loss for the three and nine months ended September 30, 2022 and 2021, dilutive net loss per common share is the same as basic net loss per common share for those periods. Common stock equivalents outstanding are comprised of stock options, restricted stock units, a warrant and employee stock purchase plan rights and are only included in the calculation of diluted earnings per common share when net income is reported and their effect is dilutive. Common stock equivalents outstanding at September 30, 2022 and 2021 totaling approxim ately 9,111,000 and 6,950,000 , respectively, were excluded from the computation of dilutive weighted-average shares outstanding because their effect would be anti-dilutive. Recent Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board or other standard setting bodies that we adopt as of the specified effective date. We have evaluated recently issued accounting pronouncements and, based on our preliminary assessment, we do not believe any will have a material impact on our unaudited condensed financial statements or related footnote disclosures.

Investments

Investments	9 Months Ended
	Sep. 30, 2022
Investments, All Other Investments [Abstract]
Investments	3. Investments We invest in available-for-sale securities consisting of money market funds, U.S. Treasury securities, corporate debt securities, commercial paper, non-U.S. government debt securities, supranational debt securities and U.S. Agency bonds. Available-for-sale securities are classified as either cash and cash equivalents or short-term investments on our unaudited condensed balance sheets. The following tables summarize, by major security type, our short-term investments that are measured at fair value on a recurring basis, in thousands: September 30, 2022 Maturities Amortized Unrealized Unrealized Fair Value Cash equivalents: Money market funds 1 or less $ 80,905 $ — $ — $ 80,905 Short-term investments: U.S. Treasury securities 2 or less 146,343 — ( 3,403 ) 142,940 Corporate debt securities 2 or less 126,894 — ( 4,687 ) 122,207 Commercial paper 1 or less 37,718 — — 37,718 Non-U.S. government and supranational debt securities 2 or less 26,302 — ( 1,089 ) 25,213 U.S. Agency bonds 1 or less 8,997 — ( 237 ) 8,760 Total short-term investments 346,254 — ( 9,416 ) 336,838 Total $ 427,159 $ — $ ( 9,416 ) $ 417,743 December 31, 2021 Maturities Amortized Unrealized Unrealized Fair Value Cash equivalents: Money market funds 1 or less $ 79,895 $ — $ — $ 79,895 Short-term investments: U.S. Treasury securities 3 or less 135,452 — ( 619 ) 134,833 Corporate debt securities 3 or less 208,064 — ( 892 ) 207,172 Commercial paper 1 or less 53,439 — — 53,439 Non-U.S. government and supranational debt securities 3 or less 23,122 — ( 214 ) 22,908 U.S. Agency bonds 2 or less 8,994 — ( 58 ) 8,936 Total short-term investments 429,071 — ( 1,783 ) 427,288 Total $ 508,966 $ — $ ( 1,783 ) $ 507,183 Short-term investments are classified as current assets, even though the stated maturity date may be one year or more beyond the current balance sheet date, which reflects management’s intention to use the proceeds from sales of these securities to fund our operations, as necessary. As of September 30, 2022 and December 31, 2021, short-term investments of $ 179.2 million and $ 246.9 million, respectively, had maturities less than one year, and short-term investments of $ 157.6 million and $ 180.4 million, respectively, had maturities between one to three years. We had no realized gains or losses for the nine months ended September 30, 2022 and 2021. As of September 30, 2022, 35 av ailable-for-sale securities with a fair market value of $ 299.1 million w ere in gross unrealized loss positio ns, $ 110.6 million of wh ich were in a continuous unrealized loss position for greater than 12 months. We do not intend to sell these available-for-sale securities, and it is not more likely than not that we will be required to sell these securities prior to recovery of their amortized cost basis. Based on our review of these available-for-sale securities, the unrealized losses at September 30, 2022 were primarily due to changes in interest rates and not due to increased credit risks associated with specific securities. W e have no allowance for credit losses as of September 30, 2022 and December 31, 2021. Unrealized gains and losses that are not credit-related are included in accumulated other comprehensive (income) loss. Accrued interest receivable on available-for-sale securities was $ 1.1 million and $ 1.4 million at September 30, 2022 and December 31, 2021, respectively. We have not written off any accrued interest receivables for the nine months ended September 30, 2022 and 2021 .

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2022
Fair Value Disclosures [Abstract]
Fair Value Measurements	4. Fair Value Measurements As of September 30, 2022 and December 31, 2021, we had cash equivalents and short-term investments measured at fair value on a recurring basis. Available-for-sale securities consist of U.S. Treasury securities, which are measured at fair value using Level 1 inputs, and corporate debt securities, commercial paper, non-U.S. government debt securities, supranational debt securities and U.S. Agency bonds which are measured at fair value using Level 2 inputs. We determine the fair value of Level 2 related securities with the aid of valuations provided by third parties using proprietary valuation models and analytical tools. These valuation models and analytical tools use market pricing or prices for similar instruments that are both objective and publicly available, including matrix pricing or reported trades, benchmark yields, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids and/or offers. We validate the fair values of Level 2 financial instruments by comparing these fair values to a third-party pricing source. The following tables summarize, by major security type, our cash equivalents and short-term investments that are measured at fair value on a recurring basis and are categorized using the fair value hierarchy, in thousands: September 30, 2022 Total Level 1 Level 2 Cash equivalents: Money market funds $ 80,905 $ 80,905 $ — Short-term investments: U.S. Treasury securities 142,940 142,940 — Corporate debt securities 122,207 — 122,207 Commercial paper 37,718 — 37,718 Non-U.S. government and supranational debt securities 25,213 — 25,213 U.S. Agency bonds 8,760 — 8,760 Total short-term investments 336,838 142,940 193,898 Total $ 417,743 $ 223,845 $ 193,898 December 31, 2021 Total Level 1 Level 2 Cash equivalents: Money market funds $ 79,895 $ 79,895 $ — Short-term investments: U.S. Treasury securities 134,833 134,833 — Corporate debt securities 207,172 — 207,172 Commercial paper 53,439 — 53,439 Non-U.S. government and supranational debt securities 22,908 — 22,908 U.S. Agency bonds 8,936 — 8,936 Total short-term investments 427,288 134,833 292,455 Total $ 507,183 $ 214,728 $ 292,455

Balance Sheet Detail

Balance Sheet Detail	9 Months Ended
	Sep. 30, 2022
Balance Sheet Related Disclosures [Abstract]
Balance Sheet Detail	5. Balance Sheet Detail Property and equipment consisted of the following, in thousands: September 30, 2022 December 31, 2021 Laboratory and computer equipment $ 1,556 $ 953 Leasehold improvements 1,543 1,532 Furniture and fixtures 1,032 1,032 Property and equipment, gross 4,131 3,517 Less: accumulated depreciation ( 1,397 ) ( 844 ) Property and equipment, net $ 2,734 $ 2,673 Accounts payable and accrued expenses consisted of the following, in thousands: September 30, 2022 December 31, 2021 Accounts payable $ 1,746 $ 3,236 Accrued clinical trial research and development expenses 5,471 2,619 Accrued other research and development expenses 5,400 5,341 Accrued compensation and benefits 7,966 7,923 Other accrued expenses 1,858 1,073 Total accounts payable and accrued expenses $ 22,441 $ 20,192

Leases

Leases	9 Months Ended
	Sep. 30, 2022
Leases [Abstract]
Leases	6. Leases We currently have three operating leases for administrative and research and development office and lab space in San Diego, California and Boston, Massachusetts that expire between July 2024 and November 2025. Under the terms of the operating leases, we are required to pay our proportionate share of property taxes, insurance and normal maintenance costs. Two of our leases include renewal options for an additional five years , which were not included in the determination of the right-of-use, or ROU, asset or lease liability as the renewal was not reasonably certain at the inception of the lease . Our San Diego corporate headquarters lease and our San Diego lease for lab and office space provided for $ 1.0 million and $ 0.1 million, respectively, in reimbursements for allowable tenant improvements, which effectively reduced the total lease payments owed. Under the terms of our office lease in Boston, we are required to maintain a standby letter of credit of approximately $ 0.2 million during the term of the lease. Maturities of lease liabilities as of September 30, 2022 are as follows, in thousands: Year Ending December 31, 2022 (remaining) $ 586 2023 2,375 2024 1,863 2025 929 Total lease payments 5,753 Less: imputed interest ( 369 ) Total operating lease liabilities $ 5,384 As of September 30, 2022 and December 31, 2021 , the weighted-average discount rate was 5.5 % for both periods, and the weighted-average remaining lease term was 2.6 years and 3.3 years, respectively. Total cash paid for amounts included in the measurement of operating lease liabilities was $ 1.7 million and $ 1.5 million for the nine months ended September 30, 2022 and 2021 , respectively. There were no operating lease ROU assets obtained in exchange for operating lease liabilities for the nine months ended September 30, 2022 and 2021. Total operating lease expense for the three months ended September 30, 2022 and 2021 was approximately $ 0.5 million in both periods. Total operating lease expense for the nine months ended September 30, 2022 and 2021 was approximately $ 1.5 million in both periods.

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2022
Equity [Abstract]
Stockholders' Equity	7. Stockholders’ Equity In February 2022, we terminated the Common Stock Sales Agreement with SVB Leerink LLC and Stifel, Nicolaus & Company, Incorporated and entered into a new Common Stock Sales Agreement with SVB Securities LLC, Credit Suisse Securities (USA) LLC and Cantor Fitzgerald & Co., or the ATM Facility, under which we may offer and sell, from time to time, at our sole discretion, shares of our common stock having an aggregate offering price of up to $ 150.0 million. We have no t sold any shares of our common stock under the ATM Facility.

Share-Based Compensation

Share-Based Compensation	9 Months Ended
	Sep. 30, 2022
Share-Based Payment Arrangement [Abstract]
Share-Based Compensation	8. Share-Based Compensation The following table summarizes share-based compensation expense for all share-based compensation arrangements, in thousands: Three Months Ended Nine Months Ended September 30, September 30, 2022 2021 2022 2021 Research and development $ 2,492 $ 2,059 $ 7,545 $ 5,277 General and administrative 3,863 4,055 11,968 11,905 Total share-based compensation expense $ 6,355 $ 6,114 $ 19,513 $ 17,182 As of September 30, 2022, unrecognized estimated compensation expense related to stock options and restricted stock units was approximate ly $ 48.4 million and $ 10.8 million, re spectively, which is expected to be recognized over a weighted average period of approximatel y 2.6 years for both stock options and restricted stock units.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2022
Subsequent Events [Abstract]
Subsequent Events	9. Subsequent Events Loan and Security Agreement On November 2, 2022, we entered into a loan and security agreement, or Loan Agreement, with several banks and other financial institutions or entities party thereto, or collectively Lenders, and Hercules Capital, Inc., or Hercules, in its capacity as administrative agent and collateral agent for itself and the Lenders, or in such capacity, Agent. Under the terms of the Loan Agreement, we borrowed $ 10.0 million of an initial $ 25.0 million tranche of term loans, or the Tranche 1 Loan, and we may, at our sole discretion, borrow the remaining $ 15.0 million in respect of the Tranche 1 Loan at any time until September 15, 2023 . Thereafter, we may borrow (i) additional tranches of term loans in the amounts of up to $ 35.0 million, or the Tranche 2 Loan, and $ 40.0 million, or the Tranche 3 Loan, respectively, which will become available to us upon our satisfaction of certain terms and conditions set forth in the Loan Agreement, and (ii) a final tranche of term loans in the amount of up to $ 25.0 million, or the Tranche 4 Loan, subject to the Lenders’ investment committee approval in its sole discretion. All of the Term Loans have a maturity date of November 2, 2027 , or the Maturity Date. Repayment of the Term Loans is interest only through (a) initially, November 1, 2024 , (b) if we satisfy the Interest Only Milestone 1 Conditions (as defined in the Loan Agreement), May 1, 2025 , (c) if we satisfy the Interest Only Milestone 2 Conditions (as defined in the Loan Agreement), November 1, 2025 , and (d) if we satisfy the Approval Milestone (as defined in the Loan Agreement), November 1, 2026 . After the interest-only payment period, borrowings under the Loan Agreement are repayable in equal monthly payments of principal and accrued interest until the Maturity Date. The per annum interest rate for the Term Loans is the greater of (i) the prime rate as reported in The Wall Street Journal minus 6.25% plus 8.65% and (ii) 8.65%. At our option, we may prepay all or any portion of the outstanding Term Loans at any time. Prepayments made on or prior to the third anniversary of the date of the Loan Agreement will be subject to a prepayment fee equal to 1.50 % of the principal amount being prepaid. In addition, we paid a $ 125,000 facility charge upon closing and will pay additional facility charges in connection with any borrowing of the Tranche 2 Loan, Tranche 3 Loan or Tranche 4 Loan, in each case in the amount of 0.50 % of the amount of such tranche of loans. The Loan Agreement also provides for an end of term fee in an amount equal to the greater of (i) $ 1,512,500 (which is 6.05 % of the maximum amount of the first tranche of loans) or (ii) 6.05 % of the aggregate principal amount of loan advances actually made under the Loan Agreement, which fee is due and payable on the earliest to occur of (i) the Maturity Date, (ii) the date we prepay the outstanding loans in full, and (iii) the date that the secured obligations become due and payable. Our obligations under the Loan Agreement are secured by substantially all of our assets other than our intellectual property, but including proceeds from the sale, licensing or other disposition of our intellectual property. Our intellectual property is subject to negative covenants, which, among other things, prohibit us from selling, transferring, assigning, mortgaging, pledging, leasing, granting a security interest in or otherwise encumbering our intellectual property, subject to limited exceptions. In addition, in connection with the entry into the Loan Agreement, we issued warrants to certain of the Lenders, or collectively, the Warrants, to acquire up to 26,078 shares of our common stock at an exercise price of $ 14.38 per share, or the Warrant Shares. The Warrants may be exercised through the earlier of (i) the seventh anniversary of November 2, 2022 and (ii) the consummation of certain acquisition transactions involving us, as set forth in the Warrants. The number of Warrant Shares for which the Warrants are exercisable and the associated exercise price are subject to certain customary proportional adjustments for fundamental events, including stock splits and reverse stock splits, as set forth in the Warrants. If we make additional draws on the Tranche 2 Loan, Tranche 3 Loan or Tranche 4 Loan, upon the funding of such additional tranches, the Warrants shall become exercisable for an additional aggregate number of shares of our common stock equal to 1.50 % of each drawn amount divided by $ 14.38 per share, the exercise price per share. Securities Purchase Agreement On November 2, 2022, we entered into a securities purchase agreement with Bristol-Myers Squibb Company, or BMS, pursuant to which BMS has agreed to purchase an aggregate of 1,370,171 shares of common stock in a registered direct offering, at a purchase price of approximately $ 18.25 per share, for gross proceeds of approximately $ 25.0 million. The BMS Offering is anticipated to close on or about November 3, 2022 .

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2022
Accounting Policies [Abstract]
Reclassifications	Reclassifications Certain prior period balances have been reclassified to conform to the current period presentation.
Restricted Cash	Restricted Cash Under the terms of an office lease entered into in March 2020, we are required to maintain a standby letter of credit during the term of the lease. As of September 30, 2022 , restricted cash of $ 0.2 million was pledged as collateral for the letter of credit. The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the unaudited condensed balance sheets that sum to the total of the amounts shown in the unaudited condensed statements of cash flows, in thousands: September 30, 2022 December 31, 2021 September 30, 2021 December 31, 2020 Cash and cash equivalents $ 90,937 $ 90,672 $ 39,183 $ 325,493 Restricted cash 210 210 210 210 Total $ 91,147 $ 90,882 $ 39,393 $ 325,703
Allowance for Credit Losses on Available-for-Sale Debt Securities	Allowance for Credit Losses For available-for-sale securities in an unrealized loss position, we first assess whether we intend to sell, or if it is more likely than not that we will be required to sell, the security before recovery of its amortized cost basis. If either of the criteria regarding intent or requirement to sell is met, the security’s amortized cost basis is written down to fair value through earnings. For available-for-sale securities that do not meet the aforementioned criteria, we evaluate whether the decline in fair value has resulted from credit losses or other factors. In making this assessment, we consider the severity of the impairment, any changes in interest rates, market conditions, changes to the underlying credit ratings and forecasted recovery, among other factors. The credit-related portion of unrealized losses, and any subsequent improvements, are recorded in interest income through an allowance account. Any impairment that has not been recorded through an allowance for credit losses is included in other comprehensive income (loss) on the unaudited condensed statements of operations and comprehensive loss. We elected the practical expedient to exclude the applicable accrued interest from both the fair value and amortized costs basis of our available-for-sale securities for purposes of identifying and measuring an impairment. Accrued interest receivable on available-for-sale securities is recorded within prepaid expenses and other current assets on our unaudited condensed balance sheets. Our accounting policy is to not measure an allowance for credit loss for accrued interest receivable and to write-off any uncollectible accrued interest receivable as a reversal of interest income in a timely manner, which we consider to be in the period in which we determine the accrued interest will not be collected by us.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that potentially subject us to significant concentrations of credit risk consist primarily of cash, cash equivalents and short-term investments. We maintain deposits in federally insured financial institutions in excess of federally insured limits. We have established guidelines to limit our exposure to credit risk by placing investments with high credit quality financial institutions, diversifying our investment portfolio and placing investments with maturities that maintain safety and liquidity. We periodically review and modify these guidelines to maximize trends in yields and interest rates without compromising safety and liquidity.
Net Loss per Share	Net Loss per Share Basic net loss per common share is calculated by dividing the net loss by the weighted-average number of common shares outstanding for the period, without consideration for common stock equivalents. Diluted net loss per share is calculated by dividing the net loss by the weighted-average number of common shares and common stock equivalents outstanding for the period determined using the treasury-stock method. As we have reported net loss for the three and nine months ended September 30, 2022 and 2021, dilutive net loss per common share is the same as basic net loss per common share for those periods. Common stock equivalents outstanding are comprised of stock options, restricted stock units, a warrant and employee stock purchase plan rights and are only included in the calculation of diluted earnings per common share when net income is reported and their effect is dilutive. Common stock equivalents outstanding at September 30, 2022 and 2021 totaling approxim ately 9,111,000 and 6,950,000 , respectively, were excluded from the computation of dilutive weighted-average shares outstanding because their effect would be anti-dilutive.
Recent Accounting Pronouncements	Recent Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board or other standard setting bodies that we adopt as of the specified effective date. We have evaluated recently issued accounting pronouncements and, based on our preliminary assessment, we do not believe any will have a material impact on our unaudited condensed financial statements or related footnote disclosures.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2022
Accounting Policies [Abstract]
Schedule of Reconciliation of Cash, Cash Equivalents and Restricted Cash	The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the unaudited condensed balance sheets that sum to the total of the amounts shown in the unaudited condensed statements of cash flows, in thousands: September 30, 2022 December 31, 2021 September 30, 2021 December 31, 2020 Cash and cash equivalents $ 90,937 $ 90,672 $ 39,183 $ 325,493 Restricted cash 210 210 210 210 Total $ 91,147 $ 90,882 $ 39,393 $ 325,703

Investments (Tables)

Investments (Tables)	9 Months Ended
	Sep. 30, 2022
Investments, All Other Investments [Abstract]
Investments Measured at Fair Value on Recurring Basis	The following tables summarize, by major security type, our short-term investments that are measured at fair value on a recurring basis, in thousands: September 30, 2022 Maturities Amortized Unrealized Unrealized Fair Value Cash equivalents: Money market funds 1 or less $ 80,905 $ — $ — $ 80,905 Short-term investments: U.S. Treasury securities 2 or less 146,343 — ( 3,403 ) 142,940 Corporate debt securities 2 or less 126,894 — ( 4,687 ) 122,207 Commercial paper 1 or less 37,718 — — 37,718 Non-U.S. government and supranational debt securities 2 or less 26,302 — ( 1,089 ) 25,213 U.S. Agency bonds 1 or less 8,997 — ( 237 ) 8,760 Total short-term investments 346,254 — ( 9,416 ) 336,838 Total $ 427,159 $ — $ ( 9,416 ) $ 417,743 December 31, 2021 Maturities Amortized Unrealized Unrealized Fair Value Cash equivalents: Money market funds 1 or less $ 79,895 $ — $ — $ 79,895 Short-term investments: U.S. Treasury securities 3 or less 135,452 — ( 619 ) 134,833 Corporate debt securities 3 or less 208,064 — ( 892 ) 207,172 Commercial paper 1 or less 53,439 — — 53,439 Non-U.S. government and supranational debt securities 3 or less 23,122 — ( 214 ) 22,908 U.S. Agency bonds 2 or less 8,994 — ( 58 ) 8,936 Total short-term investments 429,071 — ( 1,783 ) 427,288 Total $ 508,966 $ — $ ( 1,783 ) $ 507,183

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2022
Fair Value Disclosures [Abstract]
Schedule Of Fair Value Measurements, By Major Security Type	The following tables summarize, by major security type, our cash equivalents and short-term investments that are measured at fair value on a recurring basis and are categorized using the fair value hierarchy, in thousands: September 30, 2022 Total Level 1 Level 2 Cash equivalents: Money market funds $ 80,905 $ 80,905 $ — Short-term investments: U.S. Treasury securities 142,940 142,940 — Corporate debt securities 122,207 — 122,207 Commercial paper 37,718 — 37,718 Non-U.S. government and supranational debt securities 25,213 — 25,213 U.S. Agency bonds 8,760 — 8,760 Total short-term investments 336,838 142,940 193,898 Total $ 417,743 $ 223,845 $ 193,898 December 31, 2021 Total Level 1 Level 2 Cash equivalents: Money market funds $ 79,895 $ 79,895 $ — Short-term investments: U.S. Treasury securities 134,833 134,833 — Corporate debt securities 207,172 — 207,172 Commercial paper 53,439 — 53,439 Non-U.S. government and supranational debt securities 22,908 — 22,908 U.S. Agency bonds 8,936 — 8,936 Total short-term investments 427,288 134,833 292,455 Total $ 507,183 $ 214,728 $ 292,455

Balance Sheet Detail (Tables)

Balance Sheet Detail (Tables)	9 Months Ended
	Sep. 30, 2022
Balance Sheet Related Disclosures [Abstract]
Summary of Property and Equipment	Property and equipment consisted of the following, in thousands: September 30, 2022 December 31, 2021 Laboratory and computer equipment $ 1,556 $ 953 Leasehold improvements 1,543 1,532 Furniture and fixtures 1,032 1,032 Property and equipment, gross 4,131 3,517 Less: accumulated depreciation ( 1,397 ) ( 844 ) Property and equipment, net $ 2,734 $ 2,673
Summary of Accounts Payable and Accrued Expenses	Accounts payable and accrued expenses consisted of the following, in thousands: September 30, 2022 December 31, 2021 Accounts payable $ 1,746 $ 3,236 Accrued clinical trial research and development expenses 5,471 2,619 Accrued other research and development expenses 5,400 5,341 Accrued compensation and benefits 7,966 7,923 Other accrued expenses 1,858 1,073 Total accounts payable and accrued expenses $ 22,441 $ 20,192

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2022
Leases [Abstract]
Schedule of Maturities of Lease Liabilities	Maturities of lease liabilities as of September 30, 2022 are as follows, in thousands: Year Ending December 31, 2022 (remaining) $ 586 2023 2,375 2024 1,863 2025 929 Total lease payments 5,753 Less: imputed interest ( 369 ) Total operating lease liabilities $ 5,384

Share-Based Compensation (Table

Share-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2022
Share-Based Payment Arrangement [Abstract]
Summary of Share-based Compensation Expense	The following table summarizes share-based compensation expense for all share-based compensation arrangements, in thousands: Three Months Ended Nine Months Ended September 30, September 30, 2022 2021 2022 2021 Research and development $ 2,492 $ 2,059 $ 7,545 $ 5,277 General and administrative 3,863 4,055 11,968 11,905 Total share-based compensation expense $ 6,355 $ 6,114 $ 19,513 $ 17,182

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021	Dec. 31, 2020
Summary Of Significant Accounting Policies [Line Items]
Restricted cash pledged as collateral	$ 210	$ 210	$ 210	$ 210
Total potentially dilutive securities	9,111,000	6,950,000
Collateral Pledged
Summary Of Significant Accounting Policies [Line Items]
Restricted cash pledged as collateral	$ 200

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Schedule of Reconciliation of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021	Sep. 30, 2021	Dec. 31, 2020
Accounting Policies [Abstract]
Cash and cash equivalents	$ 90,937	$ 90,672	$ 39,183	$ 325,493
Restricted cash	210	210	210	210
Total	$ 91,147	$ 90,882	$ 39,393	$ 325,703

Investments - Investments Measu

Investments - Investments Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2022	Dec. 31, 2021
Schedule Of Available For Sale Securities [Line Items]
Short-term investments, Fair Value	$ 336,838	$ 427,288
Fair Value Measurements on Recurring Basis
Schedule Of Available For Sale Securities [Line Items]
Short-term investments, Amortized Cost	346,254	429,071
Short-term investments, Unrealized Losses	(9,416)	(1,783)
Short-term investments, Fair Value	336,838	427,288
Cash equivalents and Short-term investments, Amortized Cost	427,159	508,966
Cash equivalents and Short-term investments, Unrealized Losses	(9,416)	(1,783)
Cash equivalents and Short-term investments, Estimated Fair Value	$ 417,743	$ 507,183
Fair Value Measurements on Recurring Basis | Money Market Funds
Schedule Of Available For Sale Securities [Line Items]
Maturities (years)	1 or less	1 or less
Cash equivalents, Amortized Cost	$ 80,905	$ 79,895
Cash equivalents, Fair Value	80,905	79,895
Fair Value Measurements on Recurring Basis | U.S. Treasury Securities
Schedule Of Available For Sale Securities [Line Items]
Short-term investments, Amortized Cost	146,343	135,452
Short-term investments, Unrealized Losses	(3,403)	(619)
Short-term investments, Fair Value	$ 142,940	$ 134,833
Fair Value Measurements on Recurring Basis | U.S. Treasury Securities | Maximum
Schedule Of Available For Sale Securities [Line Items]
Maturities (years)	2 years	3 years
Fair Value Measurements on Recurring Basis | Corporate Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Short-term investments, Amortized Cost	$ 126,894	$ 208,064
Short-term investments, Unrealized Losses	(4,687)	(892)
Short-term investments, Fair Value	$ 122,207	$ 207,172
Fair Value Measurements on Recurring Basis | Corporate Debt Securities | Maximum
Schedule Of Available For Sale Securities [Line Items]
Maturities (years)	2 years	3 years
Fair Value Measurements on Recurring Basis | Commercial Paper
Schedule Of Available For Sale Securities [Line Items]
Short-term investments, Amortized Cost	$ 37,718	$ 53,439
Short-term investments, Fair Value	$ 37,718	$ 53,439
Fair Value Measurements on Recurring Basis | Commercial Paper | Maximum
Schedule Of Available For Sale Securities [Line Items]
Maturities (years)	1 year	1 year
Fair Value Measurements on Recurring Basis | Non U S Government And Supranational Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Short-term investments, Amortized Cost	$ 26,302	$ 23,122
Short-term investments, Unrealized Losses	(1,089)	(214)
Short-term investments, Fair Value	$ 25,213	$ 22,908
Fair Value Measurements on Recurring Basis | Non U S Government And Supranational Debt Securities | Maximum
Schedule Of Available For Sale Securities [Line Items]
Maturities (years)	2 years	3 years
Fair Value Measurements on Recurring Basis | U.S. Agency Bonds
Schedule Of Available For Sale Securities [Line Items]
Short-term investments, Amortized Cost	$ 8,997	$ 8,994
Short-term investments, Unrealized Losses	(237)	(58)
Short-term investments, Fair Value	$ 8,760	$ 8,936
Fair Value Measurements on Recurring Basis | U.S. Agency Bonds | Maximum
Schedule Of Available For Sale Securities [Line Items]
Maturities (years)	1 year	2 years

Investments - Additional Inform

Investments - Additional Information (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2022 USD ($) Security	Dec. 31, 2021 USD ($)
Investments, All Other Investments [Abstract]
Short-term investments with maturities less than one year	$ 179,200	$ 246,900
Short-term investments with maturities between one to three years	$ 157,600	180,400
Short-term investments maturities, description	As of September 30, 2022 and December 31, 2021, short-term investments of $179.2 million and $246.9 million, respectively, had maturities less than one year, and short-term investments of $157.6 million and $180.4 million, respectively, had maturities between one to three years.
Allowance for credit losses	$ 0	0
Available for sale securities gross unrealized loss positions	299,100
Available for sale securities gross unrealized loss positions greater than 12 months	$ 110,600
Number of available-for-sale securities | Security	35
Accrued interest receivable on available-for-sale securities	$ 1,100	$ 1,400

Fair Value Measurements - Sched

Fair Value Measurements - Schedule Of Fair Value Measurements, By Major Security Type (Detail) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	$ 336,838	$ 427,288
Fair Value Measurements on Recurring Basis
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	336,838	427,288
Cash equivalents and short-term investments	417,743	507,183
Fair Value Measurements on Recurring Basis | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	142,940	134,833
Cash equivalents and short-term investments	223,845	214,728
Fair Value Measurements on Recurring Basis | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	193,898	292,455
Cash equivalents and short-term investments	193,898	292,455
Fair Value Measurements on Recurring Basis | Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	80,905	79,895
Fair Value Measurements on Recurring Basis | Money Market Funds | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	80,905	79,895
Fair Value Measurements on Recurring Basis | U.S. Treasury Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	142,940	134,833
Fair Value Measurements on Recurring Basis | U.S. Treasury Securities | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	142,940	134,833
Fair Value Measurements on Recurring Basis | Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	122,207	207,172
Fair Value Measurements on Recurring Basis | Corporate Debt Securities | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	122,207	207,172
Fair Value Measurements on Recurring Basis | Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	37,718	53,439
Fair Value Measurements on Recurring Basis | Commercial Paper | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	37,718	53,439
Fair Value Measurements on Recurring Basis | Non U S Government And Supranational Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	25,213	22,908
Fair Value Measurements on Recurring Basis | Non U S Government And Supranational Debt Securities | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	25,213	22,908
Fair Value Measurements on Recurring Basis | U S Agency Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	8,760	8,936
Fair Value Measurements on Recurring Basis | U S Agency Bonds | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	$ 8,760	$ 8,936

Balance Sheet Detail - Summary

Balance Sheet Detail - Summary of Property and Equipment (Detail) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 4,131	$ 3,517
Less: accumulated depreciation	(1,397)	(844)
Property and equipment, net	2,734	2,673
Laboratory and Computer Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	1,556	953
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	1,543	1,532
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 1,032	$ 1,032

Balance Sheet Detail - Summar_2

Balance Sheet Detail - Summary of Current Accrued Expenses (Detail) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Accrued Liabilities, Current [Abstract]
Accounts payable	$ 1,746	$ 3,236
Accrued clinical trial research and development expenses	5,471	2,619
Accrued other research and development expenses	5,400	5,341
Accrued compensation and benefits	7,966	7,923
Other accrued expenses	1,858	1,073
Total accounts payable and accrued expenses	$ 22,441	$ 20,192

Leases - Additional Information

Leases - Additional Information (Detail) - USD ($)	1 Months Ended		3 Months Ended		9 Months Ended
	May 31, 2020	Mar. 31, 2020	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	May 31, 2022	Dec. 31, 2021
Lessee Lease Description [Line Items]
Lessee, operating lease, expiration period					We currently have three operating leases for administrative and research and development office and lab space in San Diego, California and Boston, Massachusetts that expire between July 2024 and November 2025.
Lease option to extend, description					Two of our leases include renewal options for an additional five years, which were not included in the determination of the right-of-use, or ROU, asset or lease liability as the renewal was not reasonably certain at the inception of the lease
Weighted-average discount rate			5.50%		5.50%			5.50%
Weighted-average remaining lease term			2 years 7 months 6 days		2 years 7 months 6 days			3 years 3 months 18 days
Total cash paid for amounts included in the measurement of lease liabilities					$ 1,700,000	$ 1,500,000
ROU assets obtained in exchange for operating lease liabilities					0	0
ASC 842
Lessee Lease Description [Line Items]
Total operating lease rent expense			$ 500,000	$ 500,000	1,500,000	$ 1,500,000
San Diego Corporate Headquarters Lease
Lessee Lease Description [Line Items]
Operating lease, existence of option to extend		true
Lease agreement additional extended lease term	5 years
Tenant improvement allowance	$ 1,000,000
San Diego Lease for Lab and Office Space
Lessee Lease Description [Line Items]
Tenant improvement allowance							$ 100,000
Office Lease in Boston | Letter of Credit
Lessee Lease Description [Line Items]
Letter of Credit			$ 200,000		$ 200,000
Boston Lease
Lessee Lease Description [Line Items]
Operating lease, existence of option to extend	true
Lease agreement additional extended lease term		5 years

Leases - Schedule of Maturities

Leases - Schedule of Maturities of Lease Liabilities (Detail) $ in Thousands	Sep. 30, 2022 USD ($)
Leases [Abstract]
2022 (remaining)	$ 586
2023	2,375
2024	1,863
2025	929
Total lease payments	5,753
Less: imputed interest	(369)
Operating Lease Liability	$ 5,384

Stockholder's Equity - Addition

Stockholder's Equity - Additional Information (Detail) - SVB Securities LLC, Credit Suisse Securities (USA) LLC and Cantor Fitzgerald & Co. - ATM Facility - USD ($) $ in Millions	1 Months Ended	9 Months Ended
	Feb. 28, 2022	Sep. 30, 2022
Class of Stock [Line Items]
Common stock, shares issued		0
Maximum
Class of Stock [Line Items]
Aggregate offering price	$ 150

Share-Based Compensation - Summ

Share-Based Compensation - Summary of Share-based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense	$ 6,355	$ 6,114	$ 19,513	$ 17,182
Research and development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense	2,492	2,059	7,545	5,277
General and administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense	$ 3,863	$ 4,055	$ 11,968	$ 11,905

Share-Based Compensation - Addi

Share-Based Compensation - Additional Information (Detail) $ in Millions	9 Months Ended
	Sep. 30, 2022 USD ($)
Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized estimated stock option compensation expenses	$ 48.4
Weighted average service period	2 years 7 months 6 days
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized estimated restricted stock units compensation expenses	$ 10.8
Weighted average service period	2 years 7 months 6 days

Subsequent Events - Additional

Subsequent Events - Additional Information (Details) - USD ($)		9 Months Ended
	Nov. 02, 2022	Sep. 30, 2022
Securities Purchase Agreement
Subsequent Event [Line Items]
Stock offering, Transaction date		Nov. 03, 2022
Term Loan | Loan and Security Agreement
Subsequent Event [Line Items]
Tranche 1 availability end date		Nov. 02, 2027
Principal and interest payments start date		Nov. 01, 2024
Term loan facility per annum interest rate terms		The per annum interest rate for the Term Loans is the greater of (i) the prime rate as reported in The Wall Street Journal minus 6.25% plus 8.65% and (ii) 8.65%.
Interest Only Milestone 1 Conditions | Loan and Security Agreement
Subsequent Event [Line Items]
Repayment of term loan facility start date		May 01, 2025
Interest Only Milestone 2 Conditions | Loan and Security Agreement
Subsequent Event [Line Items]
Repayment of term loan facility start date		Nov. 01, 2025
Approval Milestone | Loan and Security Agreement
Subsequent Event [Line Items]
Repayment of term loan facility start date		Nov. 01, 2026
Subsequent Event | Loan and Security Agreement
Subsequent Event [Line Items]
Warrant issued	26,078
Warrants exercisable exercise price	$ 14.38
Subsequent Event | Securities Purchase Agreement
Subsequent Event [Line Items]
Common stock, shares issued	1,370,171
Common stock, issued price per share	$ 18.25
Proceeds from issuances of common stock, gross	$ 25,000,000
Subsequent Event | Tranche 1 Loan | Loan and Security Agreement
Subsequent Event [Line Items]
Maximum borrowing capacity under term loans	25,000,000
Remaining borrowing capacity under term loans	$ 15,000,000
Tranche 1 availability end date	Sep. 15, 2023
Subsequent Event | Tranche 1 draw | Loan and Security Agreement
Subsequent Event [Line Items]
Principal amount outstanding on loan	$ 10,000,000
Subsequent Event | Tranche 2 Loan | Loan and Security Agreement
Subsequent Event [Line Items]
Maximum borrowing capacity under term loans	35,000,000
Subsequent Event | Tranche 3 Loan | Loan and Security Agreement
Subsequent Event [Line Items]
Maximum borrowing capacity under term loans	40,000,000
Subsequent Event | Tranche 4 Loan | Loan and Security Agreement
Subsequent Event [Line Items]
Maximum borrowing capacity under term loans	$ 25,000,000
Subsequent Event | Additional Tranche | Loan and Security Agreement
Subsequent Event [Line Items]
Warrants exercisable exercise price	$ 14.38
Percentage of additional warrant	1.50%
Subsequent Event | Term Loan | Loan and Security Agreement
Subsequent Event [Line Items]
Commitment fees	$ 125,000
Percentage of prepayment fee to be paid due to early payment	1.50%
Percentage of facility charge	0.50%
Final payment	$ 1,512,500
Final payment percentage	6.05%
Subsequent Event | Term Loan | Loan and Security Agreement | Maximum
Subsequent Event [Line Items]
Final payment percentage	6.05%