Kura Oncology (KURA) 10-Q 2 Nov 23 2023 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2023	Oct. 26, 2023
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2023
Document Fiscal Year Focus	2023
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		74,272,111
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, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 28,740	$ 51,802
Short-term investments	423,853	386,183
Prepaid expenses and other current assets	7,324	8,441
Total current assets	459,917	446,426
Property and equipment, net	2,057	2,540
Operating lease right-of-use assets	7,281	3,842
Other long-term assets	4,516	3,498
Total assets	473,771	456,306
Current liabilities:
Accounts payable and accrued expenses	25,843	21,739
Current operating lease liabilities	1,682	2,318
Total current liabilities	27,525	24,057
Long-term debt, net	9,289	9,158
Long-term operating lease liabilities	6,453	2,548
Other long-term liabilities	567	265
Total liabilities	43,834	36,028
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; 74,251 and 68,314 shares issued and outstanding as of September 30, 2023 and December 31, 2022, respectively	7	7
Additional paid-in capital	1,112,118	997,111
Accumulated other comprehensive loss	(3,535)	(8,032)
Accumulated deficit	(678,653)	(568,808)
Total stockholders'equity	429,937	420,278
Total liabilities and stockholders'equity	$ 473,771	$ 456,306

Condensed Balance Sheets (Una_2

Condensed Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Sep. 30, 2023	Dec. 31, 2022
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	74,251,000	68,314,000
Common stock, shares outstanding	74,251,000	68,314,000

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, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Operating Expenses:
Research and development	$ 29,328	$ 24,973	$ 82,702	$ 70,144
General and administrative	13,145	11,621	36,340	34,565
Total operating expenses	42,473	36,594	119,042	104,709
Other Income (Expense):
Interest and other income, net	4,275	1,090	10,352	1,983
Interest expense	(404)		(1,155)
Total other income, net	3,871	1,090	9,197	1,983
Net Loss	$ (38,602)	$ (35,504)	$ (109,845)	$ (102,726)
Net loss per share, basic	$ (0.50)	$ (0.53)	$ (1.53)	$ (1.54)
Net loss per share, diluted	$ (0.50)	$ (0.53)	$ (1.53)	$ (1.54)
Weighted average number of shares used in computing net loss per share, basic	77,241	66,889	71,845	66,723
Weighted average number of shares used in computing net loss per share, diluted	77,241	66,889	71,845	66,723
Comprehensive Loss:
Net Income (Loss)	$ (38,602)	$ (35,504)	$ (109,845)	$ (102,726)
Other comprehensive income (loss):
Unrealized gain (loss) on marketable securities and foreign currency	1,687	(1,601)	4,497	(7,627)
Comprehensive Loss	$ (36,915)	$ (37,105)	$ (105,348)	$ (110,353)

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, 2021	$ 506,609	$ 7	$ 941,359	$ (1,789)	$ (432,968)
Beginning balance (in shares) at Dec. 31, 2021		66,572
Share-based compensation expense	6,650		6,650
Issuance of common stock under equity plans	303		303
Issuance of common stock under equity plans, shares		64
Other comprehensive income (loss)	(4,859)			(4,859)
Net Income (Loss)	(32,453)				(32,453)
Ending balance at Mar. 31, 2022	476,250	$ 7	948,312	(6,648)	(465,421)
Ending balance (in shares) at Mar. 31, 2022		66,636
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
Net Income (Loss)	(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 Mar. 31, 2022	476,250	$ 7	948,312	(6,648)	(465,421)
Beginning balance (in shares) at Mar. 31, 2022		66,636
Share-based compensation expense	6,508		6,508
Issuance of common stock under equity plans	2,669		2,669
Issuance of common stock under equity plans, shares		202
Other comprehensive income (loss)	(1,167)			(1,167)
Net Income (Loss)	(34,769)				(34,769)
Ending balance at Jun. 30, 2022	449,491	$ 7	957,489	(7,815)	(500,190)
Ending 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 Income (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
Beginning balance at Dec. 31, 2022	420,278	$ 7	997,111	(8,032)	(568,808)
Beginning balance (in shares) at Dec. 31, 2022		68,314
Share-based compensation expense	6,838		6,838
Issuance of common stock under equity plans, shares		125
Other comprehensive income (loss)	2,136			2,136
Net Income (Loss)	(34,069)				(34,069)
Ending balance at Mar. 31, 2023	395,183	$ 7	1,003,949	(5,896)	(602,877)
Ending balance (in shares) at Mar. 31, 2023		68,439
Beginning balance at Dec. 31, 2022	420,278	$ 7	997,111	(8,032)	(568,808)
Beginning balance (in shares) at Dec. 31, 2022		68,314
Net Income (Loss)	(109,845)
Ending balance at Sep. 30, 2023	429,937	$ 7	1,112,118	(3,535)	(678,653)
Ending balance (in shares) at Sep. 30, 2023		74,251
Beginning balance at Mar. 31, 2023	395,183	$ 7	1,003,949	(5,896)	(602,877)
Beginning balance (in shares) at Mar. 31, 2023		68,439
Share-based compensation expense	6,987		6,987
Issuance of common stock under equity plans	431		431
Issuance of common stock under equity plans, shares		43
Issuance of common stock, net of offering costs, (in shares)		5,661
Issuance of common stock, net of offering costs	60,919		60,919
Issuance of pre-funded warrants to purchase common stock, net of offering costs	32,658		32,658
Other comprehensive income (loss)	674			674
Net Income (Loss)	(37,174)				(37,174)
Ending balance at Jun. 30, 2023	459,678	$ 7	1,104,944	(5,222)	(640,051)
Ending balance (in shares) at Jun. 30, 2023		74,143
Share-based compensation expense	7,090		7,090
Issuance of common stock under equity plans	84		84
Issuance of common stock under equity plans, shares		108
Other comprehensive income (loss)	1,687			1,687
Net Income (Loss)	(38,602)				(38,602)
Ending balance at Sep. 30, 2023	$ 429,937	$ 7	$ 1,112,118	$ (3,535)	$ (678,653)
Ending balance (in shares) at Sep. 30, 2023		74,251

Condensed Statements of Cash Fl

Condensed Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Operating Activities
Net Income (Loss)	$ (109,845)	$ (102,726)
Adjustments to reconcile net loss to net cash used in operating activities:
Share-based compensation expense	20,915	19,513
Amortization of premium and accretion of discounts on marketable securities, net	(6,687)	2,264
Depreciation expense	635	553
Non-cash interest expense	358
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	574	(4,287)
Operating lease right-of-use and other long-term assets	778	226
Accounts payable and accrued expenses	2,681	758
Other long-term liabilities	75	167
Net cash used in operating activities	(90,516)	(83,532)
Investing Activities
Purchases of marketable securities	(310,135)	(164,532)
Maturities of marketable securities	283,649	245,091
Purchases of property and equipment	(152)	(614)
Net cash (used in) provided by investing activities	(26,638)	79,945
Financing Activities
Proceeds from issuance of common stock and pre-funded warrants, net of offering costs	93,577
Proceeds from issuance of stock under equity plans	515	3,852
Net cash provided by financing activities	94,092	3,852
Net (decrease) increase in cash and cash equivalents	(23,062)	265
Cash and cash equivalents at beginning of period	51,802	90,672
Cash and cash equivalents at end of period	$ 28,740	$ 90,937

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022
Pay vs Performance Disclosure
Net Income (Loss)	$ (38,602)	$ (37,174)	$ (34,069)	$ (35,504)	$ (34,769)	$ (32,453)	$ (109,845)	$ (102,726)

Insider Trading Arrangements

Insider Trading Arrangements	9 Months Ended
	Sep. 30, 2023 shares
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	Trading Plans During the three months ended September 30, 2023, certain of our officers adopted or terminated contracts, instructions or written plans for the purchase or sale of our securities as noted below: Trading Arrangement Action Date Rule 10b5-1* Non-Rule 10b5-1** Total Shares to be Sold Expiration Date Teresa Bair, Chief Legal Officer Adoption September 22, 2023 X ESPP net shares to be purchased May 31, 2024 Kathleen Ford, Chief Operating Officer Adoption August 29, 2023 X 136,261 September 15, 2024 ______________________ * Intended to satisfy the affirmative defense of Rule 10b5-1(c) ** Not intended to satisfy the affirmative defense of Rule 10b5-1(c)
Rule 10b5-1 Arrangement Adopted	true
Rule 10b5-1 Arrangement Terminated	true
Teresa Bair, Chief Legal Officer
Trading Arrangements, by Individual
Name	Teresa Bair, Chief Legal Officer
Rule 10b5-1 Arrangement Adopted	true
Non-Rule 10b5-1 Arrangement Adopted	false
Adoption Date	September 22, 2023
Expiration Date	May 31, 2024
Kathleen Ford, Chief Operating Officer
Trading Arrangements, by Individual
Name	Kathleen Ford, Chief Operating Officer
Rule 10b5-1 Arrangement Adopted	true
Non-Rule 10b5-1 Arrangement Adopted	false
Adoption Date	August 29, 2023
Aggregate Available	136,261
Expiration Date	September 15, 2024

Organization and Basis of Prese

Organization and Basis of Presentation	9 Months Ended
	Sep. 30, 2023
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, 2022, as filed with the Securities and Exchange Commission on February 23, 2023, from which we derived our balance sheet as of December 31, 2022. 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. By their nature, estimates are subject to an inherent degree of uncertainty and, as such, actual results may differ from management’s estimates.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Reclassifications The prior period restricted cash balance of approximately $ 0.2 million has been reclassified to other long-term assets in the accompanying unaudited condensed financial statem ents. See Note 6, Leases, for further details. 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. Employee Retention Credit Under the Coronavirus Aid, Relief, and Economic Security Act of 2020, or CARES Act, we were eligible to claim the employee retention credit, which is a refundable tax credit against certain employment taxes. For the nine months ended September 30, 2023 , we recognized $ 2.8 million of employee retention credits related to wages paid to our employees from July 2020 through September 2021 within operating expenses as a reduction to personnel costs in the unaudited condensed statements of operations and comprehensive loss. We file d for the credit with the Internal Revenue Service in the first quarter of 2023. As of September 30, 2023 , an employee retention credit receivable of $ 2.8 million w as included within prepaid expenses and other current assets in the unaudited condensed balance sheets, and we expect to receive such credit in the form of a cash payment during the second half of 2023. 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, which includes the shares related to outstanding pre-funded warrants (see Note 7), but excludes other potential common stock equivalents. Pre-funded warrants are considered outstanding for the purposes of computing basic and diluted net loss per share because shares may be issued for little or no additional consideration, and are fully vested and exercisable. Diluted net loss per share is calculated by dividing net loss by the weighted-average number of common shares and common stock equivalents outstanding for the period. As we have reported net loss for the three and nine months ended September 30, 2023 and 2022, 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, performance-based restricted stock units, warrants 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, 2023 and 2022 totaling approxim ately 12,664,000 and 9,111,000 , 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, 2023
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, U.S. Agency bonds and non-U.S. government debt securities. 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, 2023 Maturities Amortized Unrealized Unrealized Fair Value Cash equivalents: Money market funds 1 or less $ 9,012 $ — $ — $ 9,012 Short-term investments: U.S. Treasury securities 2 or less 292,274 — ( 1,433 ) 290,841 Corporate debt securities 2 or less 80,622 — ( 1,691 ) 78,931 Commercial paper 1 or less 24,294 — ( 14 ) 24,280 U.S. Agency bonds 1 or less 15,273 3 ( 5 ) 15,271 Non-U.S. government debt securities 1 or less 15,000 — ( 470 ) 14,530 Total short-term investments 427,463 3 ( 3,613 ) 423,853 Total $ 436,475 $ 3 $ ( 3,613 ) $ 432,865 December 31, 2022 Maturities Amortized Unrealized Unrealized Fair Value Cash equivalents: Money market funds 1 or less $ 37,878 $ — $ — $ 37,878 U.S. Agency bonds 1 or less 9,956 — — 9,956 Total cash equivalents 47,834 — — 47,834 Short-term investments: U.S. Treasury securities 2 or less 183,051 16 ( 3,018 ) 180,049 Corporate debt securities 2 or less 115,763 — ( 3,931 ) 111,832 Commercial paper 1 or less 52,941 — — 52,941 U.S. Agency bonds 1 or less 16,192 11 ( 160 ) 16,043 Non-U.S. government and supranational debt securities 2 or less 26,268 — ( 950 ) 25,318 Total short-term investments 394,215 27 ( 8,059 ) 386,183 Total $ 442,049 $ 27 $ ( 8,059 ) $ 434,017 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, 2023 and December 31, 2022 , short-term investments of $ 369.7 million and $ 274.3 million, respectively, had maturities less than one year, and short-term investments of $ 54.2 million and $ 111.9 million, respectively, had maturities between one to two years. We had no realized gains or losses for the nine months ended September 30, 2023 and 2022. As of September 30, 2023, 63 av ailable-for-sale securities with a fair market value of $ 404.3 million w ere in gross unrealized loss po sitions, $ 139.2 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, 2023 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, 2023 and December 31, 2022. Unrealized gains and losses that are not credit-related are included in accumulated other comprehensive loss. Accrued interest receivable on available-for-sale securities was $ 1.1 million and $ 0.9 million as of September 30, 2023 and December 31, 2022, respectively. We have not written off any accrued interest receivables for the nine months ended September 30, 2023 and 2022 .

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2023
Fair Value Disclosures [Abstract]
Fair Value Measurements	4. Fair Value Measurements As of September 30, 2023 and December 31, 2022, 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, U.S. Agency bonds and non-U.S. government debt securities 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, 2023 Total Level 1 Level 2 Cash equivalents: Money market funds $ 9,012 $ 9,012 $ — Short-term investments: U.S. Treasury securities 290,841 290,841 — Corporate debt securities 78,931 — 78,931 Commercial paper 24,280 — 24,280 U.S. Agency bonds 15,271 — 15,271 Non-U.S. government debt securities 14,530 — 14,530 Total short-term investments 423,853 290,841 133,012 Total $ 432,865 $ 299,853 $ 133,012 December 31, 2022 Total Level 1 Level 2 Cash equivalents: Money market funds $ 37,878 $ 37,878 $ — U.S. Agency bonds 9,956 — 9,956 Total cash equivalents 47,834 37,878 9,956 Short-term investments: U.S. Treasury securities 180,049 180,049 — Corporate debt securities 111,832 — 111,832 Commercial paper 52,941 — 52,941 U.S. Agency bonds 16,043 — 16,043 Non-U.S. government and supranational debt securities 25,318 — 25,318 Total short-term investments 386,183 180,049 206,134 Total $ 434,017 $ 217,927 $ 216,090 We believe that our term loan facility bears interest at a rate that approximates prevailing market rates for instruments with similar characteristics and, accordingly, the carrying value of the term loan facility approximates fair value. The fair value of our term loan facility is determined using Level 2 inputs in the fair value hierarchy.

Balance Sheet Detail

Balance Sheet Detail	9 Months Ended
	Sep. 30, 2023
Balance Sheet Related Disclosures [Abstract]
Balance Sheet Detail	5. Balance Sheet Detail Property and equipment consisted of the following, in thousands: September 30, 2023 December 31, 2022 Laboratory and computer equipment $ 1,657 $ 1,568 Leasehold improvements 1,543 1,543 Furniture and fixtures 1,095 1,032 Property and equipment, gross 4,295 4,143 Less: accumulated depreciation ( 2,238 ) ( 1,603 ) Property and equipment, net $ 2,057 $ 2,540 Accounts payable and accrued expenses consisted of the following, in thousands: September 30, 2023 December 31, 2022 Accounts payable $ 1,762 $ 1,533 Accrued clinical trial research and development expenses 4,889 2,440 Accrued other research and development expenses 8,071 5,030 Accrued compensation and benefits 9,068 10,300 Other accrued expenses 2,053 2,436 Total accounts payable and accrued expenses $ 25,843 $ 21,739

Leases

Leases	9 Months Ended
	Sep. 30, 2023
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 July 2031 . 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. On August 30, 2023, we entered into an amendment to the lease agreement for office space in Boston, Massachusetts, or the Amendment, pursuant to which the term of the lease was extended by seven years , or the Extended Term, such that the lease will now expire in July 2031 . The minimum rent payable during the Extended Term is approximately $ 0.1 million per month for the first year, which amount will increase by 2 % per year over the Extended Term. The Amendment provides (i) a rent credit in the amount of approximately $ 0.5 million to be applied as a credit against the rent payments due for the months of August 2023 through July 2024, inclusive, and (ii) a tenant improvement allowance in an amount not to exceed approximately $ 0.8 million, in each case subject to certain conditions. We elected to apply the tenant improvement allowance as a credit against the rent payments due for the months of August 2024 through March 2025, inclusive. Prior to the Amendment, we were required to maintain a standby letter of credit of approximately $ 0.2 million during the term of the lease which was recorded as restricted cash in the prior period unaudited condensed balance sheets. Under the terms of the Amendment, we are required to maintain a cash deposit of approximately $ 0.2 million during the term of the lease which was included within other long-term assets in the unaudited condensed balance sheet as of September 30, 2023. Maturities of lease liabilities as of September 30, 2023 are as follows, in thousands: Year Ending December 31, 2023 (remaining) $ 464 2024 1,545 2025 1,964 2026 1,344 2027 1,371 Thereafter 5,138 Total lease payments 11,826 Less: imputed interest ( 3,691 ) Total operating lease liabilities $ 8,135 As of September 30, 2023 and December 31, 2022, the weighted-average discoun t rate was 10.3 % and 5.5 %, respectively , and the weighted-average remaining lease ter m was 6.3 years and 2.3 years, respectively. Total cash paid for amounts included in the measurement of operating lease lia bilities was $ 1.7 million for both the nine months ended September 30, 2023 and 2022 . During the nine months ended September 30, 2023, operating lease ROU assets of approximately $ 4.7 million were obtained in exchange for operating lease liabilities. No operating lease ROU assets were obtained in exchange for operating lease liabilities for the nine months ended September 30, 2022. Total operating lease expense for the three months ended September 30, 2023 and 2022 was approximately $ 0.5 million in both periods. Total operating lease expense for the nine months ended September 30, 2023 and 2022 was approximately $ 1.5 million in both periods.

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2023
Equity [Abstract]
Stockholders' Equity	7. Stockholders’ Equity In June 2023, we completed a public offering in which we sold an aggregate of 5,660,871 shares of our common stock at a price of $ 11.50 per share and pre-funded warrants to purchase 3,034,782 shares of our common stock at a price of $ 11.4999 per pre-funded warrant. The exercise price of each pre-funded warrant is $ 0.0001 per share and the pre-funded warrants are exercisable from the date of issuance until fully exercised. Net proceeds from the public offering, after deducting underwriting discounts and commissions and offering expenses, were approximately $ 93.6 million. In addition, the underwriters were granted a 30-day option to purchase up to 1,304,347 additional shares of our common stock, or the Overallotment Option, at the $ 11.50 per share public offering price. The common stock, pre-funded warrants, and Overallotment Option met the accounting standards guidance for equity classification. The Overallotment Option expired without being exercised in July 2023. We measured the fair value of the Overallotment Option using the Black-Scholes valuation model, which represents a Level 3 fair value measurement, and determined that the value was not material.

Share-Based Compensation

Share-Based Compensation	9 Months Ended
	Sep. 30, 2023
Share-Based Payment Arrangement [Abstract]
Share-Based Compensation	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, 2023 2022 2023 2022 Research and development $ 3,223 $ 2,492 $ 9,430 $ 7,545 General and administrative 3,867 3,863 11,485 11,968 Total share-based compensation expense $ 7,090 $ 6,355 $ 20,915 $ 19,513 As of September 30, 2023, unrecognized estimated compensation expense related to stock options and restricted stock units was approximate ly $ 42.0 million and $ 10.8 million, resp ectively, which is expected to be recognized over a weighted average period of approxim ately 2.6 years and 2.5 years f or stock options and restricted stock units, respectively. On May 31, 2023, upon approval by our stockholders of an amendment to our Amended and Restated 2014 Equity Incentive Plan, we granted an aggregate of 1,313,100 performance-based restricted stock units, or PSUs, to certain executives. The PSUs vest in six equal tranches upon the achievement of certain milestones and service conditions. As of September 30, 2023, we determined that the vesting of the PSUs was not probable and have not been included in share-based compensation expense or unrecognized estimated compensation expense.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2023
Accounting Policies [Abstract]
Reclassifications	Reclassifications The prior period restricted cash balance of approximately $ 0.2 million has been reclassified to other long-term assets in the accompanying unaudited condensed financial statem ents. See Note 6, Leases, for further details.
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, which includes the shares related to outstanding pre-funded warrants (see Note 7), but excludes other potential common stock equivalents. Pre-funded warrants are considered outstanding for the purposes of computing basic and diluted net loss per share because shares may be issued for little or no additional consideration, and are fully vested and exercisable. Diluted net loss per share is calculated by dividing net loss by the weighted-average number of common shares and common stock equivalents outstanding for the period. As we have reported net loss for the three and nine months ended September 30, 2023 and 2022, 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, performance-based restricted stock units, warrants 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, 2023 and 2022 totaling approxim ately 12,664,000 and 9,111,000 , 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.

Investments (Tables)

Investments (Tables)	9 Months Ended
	Sep. 30, 2023
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, 2023 Maturities Amortized Unrealized Unrealized Fair Value Cash equivalents: Money market funds 1 or less $ 9,012 $ — $ — $ 9,012 Short-term investments: U.S. Treasury securities 2 or less 292,274 — ( 1,433 ) 290,841 Corporate debt securities 2 or less 80,622 — ( 1,691 ) 78,931 Commercial paper 1 or less 24,294 — ( 14 ) 24,280 U.S. Agency bonds 1 or less 15,273 3 ( 5 ) 15,271 Non-U.S. government debt securities 1 or less 15,000 — ( 470 ) 14,530 Total short-term investments 427,463 3 ( 3,613 ) 423,853 Total $ 436,475 $ 3 $ ( 3,613 ) $ 432,865 December 31, 2022 Maturities Amortized Unrealized Unrealized Fair Value Cash equivalents: Money market funds 1 or less $ 37,878 $ — $ — $ 37,878 U.S. Agency bonds 1 or less 9,956 — — 9,956 Total cash equivalents 47,834 — — 47,834 Short-term investments: U.S. Treasury securities 2 or less 183,051 16 ( 3,018 ) 180,049 Corporate debt securities 2 or less 115,763 — ( 3,931 ) 111,832 Commercial paper 1 or less 52,941 — — 52,941 U.S. Agency bonds 1 or less 16,192 11 ( 160 ) 16,043 Non-U.S. government and supranational debt securities 2 or less 26,268 — ( 950 ) 25,318 Total short-term investments 394,215 27 ( 8,059 ) 386,183 Total $ 442,049 $ 27 $ ( 8,059 ) $ 434,017

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2023
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, 2023 Total Level 1 Level 2 Cash equivalents: Money market funds $ 9,012 $ 9,012 $ — Short-term investments: U.S. Treasury securities 290,841 290,841 — Corporate debt securities 78,931 — 78,931 Commercial paper 24,280 — 24,280 U.S. Agency bonds 15,271 — 15,271 Non-U.S. government debt securities 14,530 — 14,530 Total short-term investments 423,853 290,841 133,012 Total $ 432,865 $ 299,853 $ 133,012 December 31, 2022 Total Level 1 Level 2 Cash equivalents: Money market funds $ 37,878 $ 37,878 $ — U.S. Agency bonds 9,956 — 9,956 Total cash equivalents 47,834 37,878 9,956 Short-term investments: U.S. Treasury securities 180,049 180,049 — Corporate debt securities 111,832 — 111,832 Commercial paper 52,941 — 52,941 U.S. Agency bonds 16,043 — 16,043 Non-U.S. government and supranational debt securities 25,318 — 25,318 Total short-term investments 386,183 180,049 206,134 Total $ 434,017 $ 217,927 $ 216,090

Balance Sheet Detail (Tables)

Balance Sheet Detail (Tables)	9 Months Ended
	Sep. 30, 2023
Balance Sheet Related Disclosures [Abstract]
Summary of Property and Equipment	Property and equipment consisted of the following, in thousands: September 30, 2023 December 31, 2022 Laboratory and computer equipment $ 1,657 $ 1,568 Leasehold improvements 1,543 1,543 Furniture and fixtures 1,095 1,032 Property and equipment, gross 4,295 4,143 Less: accumulated depreciation ( 2,238 ) ( 1,603 ) Property and equipment, net $ 2,057 $ 2,540
Summary of Accounts Payable and Accrued Expenses	Accounts payable and accrued expenses consisted of the following, in thousands: September 30, 2023 December 31, 2022 Accounts payable $ 1,762 $ 1,533 Accrued clinical trial research and development expenses 4,889 2,440 Accrued other research and development expenses 8,071 5,030 Accrued compensation and benefits 9,068 10,300 Other accrued expenses 2,053 2,436 Total accounts payable and accrued expenses $ 25,843 $ 21,739

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2023
Leases [Abstract]
Schedule of Maturities of Lease Liabilities	Maturities of lease liabilities as of September 30, 2023 are as follows, in thousands: Year Ending December 31, 2023 (remaining) $ 464 2024 1,545 2025 1,964 2026 1,344 2027 1,371 Thereafter 5,138 Total lease payments 11,826 Less: imputed interest ( 3,691 ) Total operating lease liabilities $ 8,135

Share-Based Compensation (Table

Share-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2023
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, 2023 2022 2023 2022 Research and development $ 3,223 $ 2,492 $ 9,430 $ 7,545 General and administrative 3,867 3,863 11,485 11,968 Total share-based compensation expense $ 7,090 $ 6,355 $ 20,915 $ 19,513

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Summary Of Significant Accounting Policies [Line Items]
Employee retention credit recognized during period	$ 2.8
Employee retention credit receivable during period	$ 2.8
Total potentially dilutive securities	12,664,000	9,111,000
Restricted cash	$ 0.2

Investments - Investments Measu

Investments - Investments Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Schedule Of Available For Sale Securities [Line Items]
Short-term investments, Fair Value	$ 423,853	$ 386,183
Fair Value Measurements on Recurring Basis
Schedule Of Available For Sale Securities [Line Items]
Cash equivalents, Amortized Cost		47,834
Cash equivalents, Fair Value		47,834
Short-term investments, Amortized Cost	427,463	394,215
Short-term investments, Unrealized Gains	3	27
Short-term investments, Unrealized Losses	(3,613)	(8,059)
Short-term investments, Fair Value	423,853	386,183
Cash equivalents and Short-term investments, Amortized Cost	436,475	442,049
Cash equivalents and Short-term investments, Unrealized Gains	3	27
Cash equivalents and Short-term investments, Unrealized Losses	(3,613)	(8,059)
Cash equivalents and Short-term investments, Estimated Fair Value	432,865	434,017
Fair Value Measurements on Recurring Basis | Money Market Funds
Schedule Of Available For Sale Securities [Line Items]
Cash equivalents, Amortized Cost	9,012	37,878
Cash equivalents, Fair Value	$ 9,012	$ 37,878
Fair Value Measurements on Recurring Basis | Money Market Funds | Maximum
Schedule Of Available For Sale Securities [Line Items]
Maturities (years)	1 year	1 year
Fair Value Measurements on Recurring Basis | U.S. Treasury Securities
Schedule Of Available For Sale Securities [Line Items]
Short-term investments, Amortized Cost	$ 292,274	$ 183,051
Short-term investments, Unrealized Gains		16
Short-term investments, Unrealized Losses	(1,433)	(3,018)
Short-term investments, Fair Value	$ 290,841	$ 180,049
Fair Value Measurements on Recurring Basis | U.S. Treasury Securities | Maximum
Schedule Of Available For Sale Securities [Line Items]
Maturities (years)	2 years	2 years
Fair Value Measurements on Recurring Basis | Corporate Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Short-term investments, Amortized Cost	$ 80,622	$ 115,763
Short-term investments, Unrealized Losses	(1,691)	(3,931)
Short-term investments, Fair Value	$ 78,931	$ 111,832
Fair Value Measurements on Recurring Basis | Corporate Debt Securities | Maximum
Schedule Of Available For Sale Securities [Line Items]
Maturities (years)	2 years	2 years
Fair Value Measurements on Recurring Basis | Commercial Paper
Schedule Of Available For Sale Securities [Line Items]
Short-term investments, Amortized Cost	$ 24,294	$ 52,941
Short-term investments, Unrealized Losses	(14)
Short-term investments, Fair Value	$ 24,280	$ 52,941
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 | U.S. Agency Bonds
Schedule Of Available For Sale Securities [Line Items]
Cash equivalents, Amortized Cost		$ 9,956
Cash equivalents, Fair Value		9,956
Short-term investments, Amortized Cost	$ 15,273	16,192
Short-term investments, Unrealized Gains	3	11
Short-term investments, Unrealized Losses	(5)	(160)
Short-term investments, Fair Value	$ 15,271	$ 16,043
Fair Value Measurements on Recurring Basis | U.S. Agency Bonds | Maximum
Schedule Of Available For Sale Securities [Line Items]
Maturities (years)		1 year
Maturities (years)	1 year	1 year
Fair Value Measurements on Recurring Basis | Non-U.S. government debt securities
Schedule Of Available For Sale Securities [Line Items]
Short-term investments, Amortized Cost	$ 15,000
Short-term investments, Unrealized Losses	(470)
Short-term investments, Fair Value	$ 14,530
Fair Value Measurements on Recurring Basis | Non-U.S. government debt securities | Maximum
Schedule Of Available For Sale Securities [Line Items]
Maturities (years)	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		$ 26,268
Short-term investments, Unrealized Losses		(950)
Short-term investments, Fair Value		$ 25,318
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

Investments - Additional Inform

Investments - Additional Information (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2023 USD ($) Security	Dec. 31, 2022 USD ($)
Investments, All Other Investments [Abstract]
Short-term investments with maturities less than one year	$ 369,700	$ 274,300
Short-term investments with maturities between one and two years	$ 54,200	111,900
Short-term investments maturities, description	As of September 30, 2023 and December 31, 2022, short-term investments of $369.7 million and $274.3 million, respectively, had maturities less than one year, and short-term investments of $54.2 million and $111.9 million, respectively, had maturities between one to two years.
Allowance for credit losses	$ 0	0
Available for sale securities gross unrealized loss positions	404,300
Available for sale securities gross unrealized loss positions greater than 12 months	$ 139,200
Number of available-for-sale securities | Security	63
Accrued interest receivable on available-for-sale securities	$ 1,100	$ 900

Fair Value Measurements - Sched

Fair Value Measurements - Schedule Of Fair Value Measurements, By Major Security Type (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	$ 423,853	$ 386,183
Fair Value Measurements on Recurring Basis
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents		47,834
Short-term investments	423,853	386,183
Cash equivalents and short-term investments	432,865	434,017
Fair Value Measurements on Recurring Basis | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents		37,878
Short-term investments	290,841	180,049
Cash equivalents and short-term investments	299,853	217,927
Fair Value Measurements on Recurring Basis | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents		9,956
Short-term investments	133,012	206,134
Cash equivalents and short-term investments	133,012	216,090
Fair Value Measurements on Recurring Basis | Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	9,012	37,878
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	9,012	37,878
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	290,841	180,049
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	290,841	180,049
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	78,931	111,832
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	78,931	111,832
Fair Value Measurements on Recurring Basis | Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	24,280	52,941
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	24,280	52,941
Fair Value Measurements on Recurring Basis | U S Agency Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents		9,956
Short-term investments	15,271	16,043
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]
Cash equivalents		9,956
Short-term investments	15,271	16,043
Fair Value Measurements on Recurring Basis | Non-U.S. government debt securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	14,530
Fair Value Measurements on Recurring Basis | Non-U.S. government debt securities | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	$ 14,530
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		25,318
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		$ 25,318

Balance Sheet Detail - Summary

Balance Sheet Detail - Summary of Property and Equipment (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 4,295	$ 4,143
Less: accumulated depreciation	(2,238)	(1,603)
Property and equipment, net	2,057	2,540
Laboratory and Computer Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	1,657	1,568
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	1,543	1,543
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 1,095	$ 1,032

Balance Sheet Detail - Summar_2

Balance Sheet Detail - Summary of Current Accrued Expenses (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Accrued Liabilities, Current [Abstract]
Accounts payable	$ 1,762	$ 1,533
Accrued clinical trial research and development expenses	4,889	2,440
Accrued other research and development expenses	8,071	5,030
Accrued compensation and benefits	9,068	10,300
Other accrued expenses	2,053	2,436
Total accounts payable and accrued expenses	$ 25,843	$ 21,739

Leases - Additional Information

Leases - Additional Information (Detail) - USD ($)		1 Months Ended		3 Months Ended		9 Months Ended
	Aug. 30, 2023	May 31, 2020	Mar. 31, 2020	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	May 31, 2022
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 July 2031.
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				10.30%		10.30%		5.50%
Weighted-average remaining lease term				6 years 3 months 18 days		6 years 3 months 18 days		2 years 3 months 18 days
Total cash paid for amounts included in the measurement of lease liabilities						$ 1,700,000	$ 1,700,000
ROU assets obtained in exchange for operating lease liabilities						4,700,000	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]
Lessee, operating lease, expiration period	On August 30, 2023, we entered into an amendment to the lease agreement for office space in Boston, Massachusetts, or the Amendment, pursuant to which the term of the lease was extended by seven years, or the Extended Term, such that the lease will now expire in July 2031
Operating lease, existence of option to extend	true	true
Lease agreement additional extended lease term	7 years		5 years
Operating lease expense minimum rent payable per month	$ 100,000
Percentage of increase in operating lease rent expense per year	2%
Rent credit to be applied as credit, in equal monthly installments	$ 500,000
Tenant improvement allowance	800,000
Cash deposit during the term of lease	$ 200,000

Leases - Schedule of Maturities

Leases - Schedule of Maturities of Lease Liabilities (Detail) $ in Thousands	Sep. 30, 2023 USD ($)
Leases [Abstract]
2023 (remaining)	$ 464
2024	1,545
2025	1,964
2026	1,344
2027	1,371
Thereafter	5,138
Total lease payments	11,826
Less: imputed interest	(3,691)
Total operating lease liabilities	$ 8,135

Stockholder's Equity - Addition

Stockholder's Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	9 Months Ended
	Jun. 30, 2023	Sep. 30, 2023
Class of Stock [Line Items]
Common stock, shares issued	5,660,871
Common stock, issued price per share	$ 11.5
Proceeds from issuance of common stock and pre-funded warrants, net of offering costs	$ 93,600	$ 93,577
Pre-funded Warrants
Class of Stock [Line Items]
Warrants issued	3,034,782
Warrants issued price per warrants	$ 11.4999
Warrants exercisable exercise price	0.0001
Overallotment Option
Class of Stock [Line Items]
Common stock, issued price per share	$ 11.5
Option to purchase additional shares of common stock	1,304,347

Share-Based Compensation - Addi

Share-Based Compensation - Additional Information (Detail) - USD ($) $ in Millions		9 Months Ended
	May 31, 2023	Sep. 30, 2023
Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized estimated stock option compensation expenses		$ 42
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 6 months
Performance Based Restricted Stock Units | Amended and Restated 2014 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
PSUs Granted	1,313,100

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, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense	$ 7,090	$ 6,355	$ 20,915	$ 19,513
Research and development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense	3,223	2,492	9,430	7,545
General and administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense	$ 3,867	$ 3,863	$ 11,485	$ 11,968