Kura Oncology (KURA) 10-Q 2 May 24 2024 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2024	Apr. 26, 2024
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
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		76,180,620
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	Mar. 31, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 41,506	$ 37,318
Short-term investments	485,616	386,639
Prepaid expenses and other current assets	10,713	8,524
Total current assets	537,835	432,481
Property and equipment, net	1,709	1,859
Operating lease right-of-use assets	6,698	6,993
Other long-term assets	7,666	7,602
Total assets	553,908	448,935
Current liabilities:
Accounts payable and accrued expenses	30,903	33,757
Current operating lease liabilities	1,363	1,506
Total current liabilities	32,266	35,263
Long-term debt, net	9,376	9,332
Long-term operating lease liabilities	6,231	6,362
Other long-term liabilities	951	705
Total liabilities	48,824	51,662
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; 76,181 and 74,350 shares issued and outstanding as of March 31, 2024 and December 31, 2023, respectively	8	7
Additional paid-in capital	1,276,856	1,119,976
Accumulated other comprehensive loss	(816)	(1,271)
Accumulated deficit	(770,964)	(721,439)
Total stockholders'equity	505,084	397,273
Total liabilities and stockholders'equity	$ 553,908	$ 448,935

Condensed Balance Sheets (Una_2

Condensed Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Mar. 31, 2024	Dec. 31, 2023
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	76,181,000	74,350,000
Common stock, shares outstanding	76,181,000	74,350,000

Condensed Statements of Operati

Condensed Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Operating Expenses:
Research and development	$ 36,268	$ 25,192
General and administrative	18,184	11,374
Total operating expenses	54,452	36,566
Other Income (Expense):
Interest and other income, net	5,325	2,861
Interest expense	(398)	(364)
Total other income, net	4,927	2,497
Net Loss	$ (49,525)	$ (34,069)
Net loss per share, basic	$ (0.59)	$ (0.50)
Net loss per share, diluted	$ (0.59)	$ (0.50)
Weighted average number of shares used in computing net loss per share, basic	83,905	68,403
Weighted average number of shares used in computing net loss per share, diluted	83,905	68,403
Comprehensive Loss:
Net loss	$ (49,525)	$ (34,069)
Other comprehensive income:
Unrealized gain on marketable securities	455	2,136
Comprehensive Loss	$ (49,070)	$ (31,933)

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, 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 (in shares)		125
Other comprehensive income	2,136			2,136
Net 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, 2023	397,273	$ 7	1,119,976	(1,271)	(721,439)
Beginning balance (in shares) at Dec. 31, 2023		74,350
Issuance of pre-funded warrants to purchase common stock, net of offering costs	122,726		122,726
Issuance of common stock, net of offering costs	23,088	$ 1	23,087
Issuance of common stock, net of offering costs, (in shares)		1,377
Share-based compensation expense	8,512		8,512
Issuance of common stock under equity plans	2,555		2,555
Issuance of common stock under equity plans (in shares)		454
Other comprehensive income	455			455
Net loss	(49,525)				(49,525)
Ending balance at Mar. 31, 2024	$ 505,084	$ 8	$ 1,276,856	$ (816)	$ (770,964)
Ending balance (in shares) at Mar. 31, 2024		76,181

Condensed Statements of Cash Fl

Condensed Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Operating Activities
Net loss	$ (49,525)	$ (34,069)
Adjustments to reconcile net loss to net cash used in operating activities:
Amortization of premium and accretion of discounts on marketable securities, net	(3,270)	(1,687)
Share-based compensation expense	8,512	6,838
Depreciation expense	234	206
Non-cash interest expense	122	115
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(2,189)	(2,109)
Accounts payable and accrued expenses	(3,128)	(5,364)
Operating lease right-of-use and other long-term assets	231	185
Other long-term liabilities	169	13
Net cash used in operating activities	(48,844)	(35,872)
Investing Activities
Purchases of marketable securities	(195,063)	(73,835)
Maturities of marketable securities	99,810	85,000
Purchases of property and equipment	(84)	(36)
Net cash (used in) provided by investing activities	(95,337)	11,129
Financing Activities
Proceeds from issuance of common stock and pre-funded warrants, net of offering costs	145,814
Proceeds from issuance of stock under equity plans	2,555
Net cash provided by financing activities	148,369
Net increase (decrease) in cash and cash equivalents	4,188	(24,743)
Cash and cash equivalents at beginning of period	37,318	51,802
Cash and cash equivalents at end of period	$ 41,506	$ 27,059

Organization and Basis of Prese

Organization and Basis of Presentation	3 Months Ended
	Mar. 31, 2024
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 are conducting clinical trials of three product candidates: ziftomenib, tipifarnib and KO-2806. We also have additional programs that are at a discovery stage. We own global commercial rights to all of our programs and product candidates. 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, 2023, as filed with the Securities and Exchange Commission on February 27, 2024, from which we derived our balance sheet as of December 31, 2023. 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	3 Months Ended
	Mar. 31, 2024
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 statements. See Note 6, Leases, for further details. 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 three months ended March 31, 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 filed for the credit with the Internal Revenue Service in the first quarter of 2023. As of March 31, 2024, an employee retention credit receivable of $ 2.8 million was included within prepaid expenses and other current assets on the unaudited condensed balance sheets. 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 in 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, which includes the shares related to outstanding pre-funded warrants, 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 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 months ended March 31, 2024 and 2023, 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 March 31, 2024 and 2023 totaling approxim ately 14,902,000 and 11,284,000 , 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	3 Months Ended
	Mar. 31, 2024
Investments, All Other Investments [Abstract]
Investments	3. Investments We invest in available-for-sale securities consisting of U.S. Treasury securities, corporate debt securities, money market funds, non-U.S. government 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: March 31, 2024 Maturities Amortized Unrealized Unrealized Fair Value Cash equivalents: Money market funds 1 or less $ 22,800 $ — $ — $ 22,800 U.S. Treasury securities 1 or less 7,962 — — 7,962 Total cash equivalents 30,762 — — 30,762 Short-term investments: U.S. Treasury securities 2 or less 431,280 34 ( 493 ) 430,821 Corporate debt securities 1 or less 40,152 — ( 251 ) 39,901 Non-U.S. government debt securities 1 or less 15,000 — ( 106 ) 14,894 Total short-term investments 486,432 34 ( 850 ) 485,616 Total $ 517,194 $ 34 $ ( 850 ) $ 516,378 December 31, 2023 Maturities Amortized Unrealized Unrealized Fair Value Cash equivalents: Money market funds 1 or less $ 13,590 $ — $ — $ 13,590 Short-term investments: U.S. Treasury securities 2 or less 300,388 395 ( 569 ) 300,214 Corporate debt securities 2 or less 64,591 4 ( 825 ) 63,770 Non-U.S. government debt securities 1 or less 15,000 — ( 273 ) 14,727 U.S. Agency bonds 1 or less 7,931 — ( 3 ) 7,928 Total short-term investments 387,910 399 ( 1,670 ) 386,639 Total $ 401,500 $ 399 $ ( 1,670 ) $ 400,229 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 March 31, 2024 and December 31, 2023 , short-term investments of $ 436.7 million and $ 336.6 million, respectively, had maturities less than one year, and short-term investments of $ 48.9 million and $ 50.0 million, respectively, had maturities between one to two years. We had no realized gains or losses for the three months ended March 31, 2024 and 2023. As of March 31, 2024, 63 av ailable-for-sale securities with a fair market value of $ 461.4 million w ere in gross unrealized loss po sitions, $ 92.7 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 March 31, 2024 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 March 31, 2024 and December 31, 2023. 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 $ 1.5 million and $ 1.1 million as of March 31, 2024 and December 31, 2023, respectively. We have not written off any accrued interest receivables for the three months ended March 31, 2024 and 2023 .

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Fair Value Measurements	4. Fair Value Measurements As of March 31, 2024 and December 31, 2023, we had cash equivalents and short-term investments measured at fair value on a recurring basis. Available-for-sale securities consist of money market funds and U.S. Treasury securities, which are measured at fair value using Level 1 inputs, and corporate debt securities, non-U.S. government 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: March 31, 2024 Total Level 1 Level 2 Cash equivalents: Money market funds $ 22,800 $ 22,800 $ — U.S. Treasury securities 7,962 7,962 — Total cash equivalents 30,762 30,762 — Short-term investments: U.S. Treasury securities 430,821 430,821 — Corporate debt securities 39,901 — 39,901 Non-U.S. government debt securities 14,894 — 14,894 Total short-term investments 485,616 430,821 54,795 Total $ 516,378 $ 461,583 $ 54,795 December 31, 2023 Total Level 1 Level 2 Cash equivalents: Money market funds $ 13,590 $ 13,590 $ — Short-term investments: U.S. Treasury securities 300,214 300,214 — Corporate debt securities 63,770 — 63,770 Non-U.S. government debt securities 14,727 — 14,727 U.S. Agency bonds 7,928 — 7,928 Total short-term investments 386,639 300,214 86,425 Total $ 400,229 $ 313,804 $ 86,425 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	3 Months Ended
	Mar. 31, 2024
Balance Sheet Related Disclosures [Abstract]
Balance Sheet Detail	5. Balance Sheet Detail Property and equipment consisted of the following, in thousands: March 31, 2024 December 31, 2023 Laboratory and computer equipment $ 1,632 $ 1,657 Leasehold improvements 1,543 1,543 Furniture and fixtures 1,194 1,111 Property and equipment, gross 4,369 4,311 Less: accumulated depreciation ( 2,660 ) ( 2,452 ) Property and equipment, net $ 1,709 $ 1,859 Accounts payable and accrued expenses consisted of the following, in thousands: March 31, 2024 December 31, 2023 Accounts payable $ 7,529 $ 2,300 Accrued clinical trial research and development expenses 7,381 7,737 Accrued other research and development expenses 6,262 9,265 Accrued compensation and benefits 6,058 13,153 Other accrued expenses 3,673 1,302 Total accounts payable and accrued expenses $ 30,903 $ 33,757

Leases

Leases	3 Months Ended
	Mar. 31, 2024
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 August 2025 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. In August 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. 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. Maturities of lease liabilities as of March 31, 2024 are as follows, in thousands: Year Ending December 31, 2024 (remaining) $ 1,081 2025 1,964 2026 1,344 2027 1,371 2028 1,398 Thereafter 3,740 Total lease payments 10,898 Less: imputed interest ( 3,304 ) Total operating lease liabilities $ 7,594 As of March 31, 2024 and December 31, 2023, the weighted-average discoun t rate was 10.6 % and 10.4 %, respectively , and the weighted-average remaining lease ter m was 6.1 years and 6.2 years, respectively. Total cash paid for amounts included in the measurement of operating lease lia bilities was $ 0.5 million and $ 0.6 million for the three months ended March 31, 2024 and 2023, respectively . No operating lease ROU assets were obtained in exchange for operating lease liabilities for the three months ended March 31, 2024 and 2023. Total operating lease and rent expense for the three months ended March 31, 2024 and 2023 was approximately $ 0.5 million in both periods.

Stockholders' Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2024
Equity [Abstract]
Stockholders' Equity	7. Stockholders’ Equity On January 26, 2024, we completed a private placement in which we sold to certain institutional accredited investors an aggregate of 1,376,813 shares of our common stock at a purchase price of $ 17.25 per share and pre-funded warrants to purchase up to an aggregate of 7,318,886 shares of common stock at a purchase price of $ 17.2499 per pre-funded warrant (representing the $ 17.25 per share purchase price less the exercise price of $ 0.0001 per warrant share), or the Private Placement. Net proceeds from the Private Placement, after deducting expenses, were approximately $ 145.8 million. The common stock and pre-funded warrants met the accounting standards guidance for equity classification, and proceeds were allocated between common stock and pre-funded warrant based on their relative fair value.

Share-Based Compensation

Share-Based Compensation	3 Months Ended
	Mar. 31, 2024
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 March 31, 2024 2023 Research and development $ 3,885 $ 3,073 General and administrative 4,627 3,765 Total share-based compensation expense $ 8,512 $ 6,838 As of March 31, 2024, unrecognized estimated compensation expense related to stock options and restricted stock units was approximate ly $ 49.4 million and $ 16.9 million, resp ectively, which is expected to be recognized over a weighted average period of approxim ately 2.7 years and 2.8 years f or stock options and restricted stock units, respectively. In 2023, 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 March 31, 2024, we determined that the vesting of the PSUs was not probable and has not been included in share-based compensation expense or unrecognized estimated compensation expense.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2024
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 statements. See Note 6, Leases, for further details.
Employee Retention Credit	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 three months ended March 31, 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 filed for the credit with the Internal Revenue Service in the first quarter of 2023. As of March 31, 2024, an employee retention credit receivable of $ 2.8 million was included within prepaid expenses and other current assets on the unaudited condensed balance sheets.
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 in 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, 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 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 months ended March 31, 2024 and 2023, 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 March 31, 2024 and 2023 totaling approxim ately 14,902,000 and 11,284,000 , 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)	3 Months Ended
	Mar. 31, 2024
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: March 31, 2024 Maturities Amortized Unrealized Unrealized Fair Value Cash equivalents: Money market funds 1 or less $ 22,800 $ — $ — $ 22,800 U.S. Treasury securities 1 or less 7,962 — — 7,962 Total cash equivalents 30,762 — — 30,762 Short-term investments: U.S. Treasury securities 2 or less 431,280 34 ( 493 ) 430,821 Corporate debt securities 1 or less 40,152 — ( 251 ) 39,901 Non-U.S. government debt securities 1 or less 15,000 — ( 106 ) 14,894 Total short-term investments 486,432 34 ( 850 ) 485,616 Total $ 517,194 $ 34 $ ( 850 ) $ 516,378 December 31, 2023 Maturities Amortized Unrealized Unrealized Fair Value Cash equivalents: Money market funds 1 or less $ 13,590 $ — $ — $ 13,590 Short-term investments: U.S. Treasury securities 2 or less 300,388 395 ( 569 ) 300,214 Corporate debt securities 2 or less 64,591 4 ( 825 ) 63,770 Non-U.S. government debt securities 1 or less 15,000 — ( 273 ) 14,727 U.S. Agency bonds 1 or less 7,931 — ( 3 ) 7,928 Total short-term investments 387,910 399 ( 1,670 ) 386,639 Total $ 401,500 $ 399 $ ( 1,670 ) $ 400,229

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2024
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: March 31, 2024 Total Level 1 Level 2 Cash equivalents: Money market funds $ 22,800 $ 22,800 $ — U.S. Treasury securities 7,962 7,962 — Total cash equivalents 30,762 30,762 — Short-term investments: U.S. Treasury securities 430,821 430,821 — Corporate debt securities 39,901 — 39,901 Non-U.S. government debt securities 14,894 — 14,894 Total short-term investments 485,616 430,821 54,795 Total $ 516,378 $ 461,583 $ 54,795 December 31, 2023 Total Level 1 Level 2 Cash equivalents: Money market funds $ 13,590 $ 13,590 $ — Short-term investments: U.S. Treasury securities 300,214 300,214 — Corporate debt securities 63,770 — 63,770 Non-U.S. government debt securities 14,727 — 14,727 U.S. Agency bonds 7,928 — 7,928 Total short-term investments 386,639 300,214 86,425 Total $ 400,229 $ 313,804 $ 86,425

Balance Sheet Detail (Tables)

Balance Sheet Detail (Tables)	3 Months Ended
	Mar. 31, 2024
Balance Sheet Related Disclosures [Abstract]
Summary of Property and Equipment	Property and equipment consisted of the following, in thousands: March 31, 2024 December 31, 2023 Laboratory and computer equipment $ 1,632 $ 1,657 Leasehold improvements 1,543 1,543 Furniture and fixtures 1,194 1,111 Property and equipment, gross 4,369 4,311 Less: accumulated depreciation ( 2,660 ) ( 2,452 ) Property and equipment, net $ 1,709 $ 1,859
Summary of Accounts Payable and Accrued Expenses	Accounts payable and accrued expenses consisted of the following, in thousands: March 31, 2024 December 31, 2023 Accounts payable $ 7,529 $ 2,300 Accrued clinical trial research and development expenses 7,381 7,737 Accrued other research and development expenses 6,262 9,265 Accrued compensation and benefits 6,058 13,153 Other accrued expenses 3,673 1,302 Total accounts payable and accrued expenses $ 30,903 $ 33,757

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2024
Leases [Abstract]
Schedule of Maturities of Lease Liabilities	Maturities of lease liabilities as of March 31, 2024 are as follows, in thousands: Year Ending December 31, 2024 (remaining) $ 1,081 2025 1,964 2026 1,344 2027 1,371 2028 1,398 Thereafter 3,740 Total lease payments 10,898 Less: imputed interest ( 3,304 ) Total operating lease liabilities $ 7,594

Share-Based Compensation (Table

Share-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2024
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 March 31, 2024 2023 Research and development $ 3,885 $ 3,073 General and administrative 4,627 3,765 Total share-based compensation expense $ 8,512 $ 6,838

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
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	14,902,000	11,284,000
Restricted cash	$ 0.2

Investments - Investments Measu

Investments - Investments Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Schedule Of Available For Sale Securities [Line Items]
Short-term investments, Estimated Fair Value	$ 485,616	$ 386,639
Fair Value Measurements on Recurring Basis
Schedule Of Available For Sale Securities [Line Items]
Cash equivalents, Amortized Cost	30,762
Cash equivalents, Estimated Fair Value	30,762
Short-term investments, Amortized Cost	486,432	387,910
Short-term investments, Unrealized Gains	34	399
Short-term investments, Unrealized Losses	(850)	(1,670)
Short-term investments, Estimated Fair Value	485,616	386,639
Cash equivalents and Short-term investments, Amortized Cost	517,194	401,500
Cash equivalents and Short-term investments, Unrealized Gains	34	399
Cash equivalents and Short-term investments, Unrealized Losses	(850)	(1,670)
Cash equivalents and Short-term investments, Estimated Fair Value	516,378	400,229
Fair Value Measurements on Recurring Basis | Money Market Funds
Schedule Of Available For Sale Securities [Line Items]
Cash equivalents, Amortized Cost	22,800	13,590
Cash equivalents, Estimated Fair Value	$ 22,800	$ 13,590
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]
Cash equivalents, Amortized Cost	$ 7,962
Cash equivalents, Estimated Fair Value	7,962
Short-term investments, Amortized Cost	431,280	$ 300,388
Short-term investments, Unrealized Gains	34	395
Short-term investments, Unrealized Losses	(493)	(569)
Short-term investments, Estimated Fair Value	$ 430,821	$ 300,214
Fair Value Measurements on Recurring Basis | U.S. Treasury Securities | Maximum
Schedule Of Available For Sale Securities [Line Items]
Maturities (years)	1 year
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	$ 40,152	$ 64,591
Short-term investments, Unrealized Gains		4
Short-term investments, Unrealized Losses	(251)	(825)
Short-term investments, Estimated Fair Value	$ 39,901	$ 63,770
Fair Value Measurements on Recurring Basis | Corporate Debt Securities | Maximum
Schedule Of Available For Sale Securities [Line Items]
Maturities (years)	1 year	2 years
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	$ 15,000
Short-term investments, Unrealized Losses	(106)	(273)
Short-term investments, Estimated Fair Value	$ 14,894	$ 14,727
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	1 year
Fair Value Measurements on Recurring Basis | U.S. Agency Bonds
Schedule Of Available For Sale Securities [Line Items]
Short-term investments, Amortized Cost		$ 7,931
Short-term investments, Unrealized Losses		(3)
Short-term investments, Estimated Fair Value		$ 7,928
Fair Value Measurements on Recurring Basis | U.S. Agency Bonds | Maximum
Schedule Of Available For Sale Securities [Line Items]
Maturities (years)		1 year

Investments - Additional Inform

Investments - Additional Information (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($) Security	Dec. 31, 2023 USD ($)
Investments, All Other Investments [Abstract]
Short-term investments with maturities less than one year	$ 436,700	$ 336,600
Short-term investments with maturities between one to two years	$ 48,900	50,000
Short-term investments maturities, description	As of March 31, 2024 and December 31, 2023, short-term investments of $436.7 million and $336.6 million, respectively, had maturities less than one year, and short-term investments of $48.9 million and $50.0 million, respectively, had maturities between one to two years.
Allowance for credit losses	$ 0	0
Available for sale securities gross unrealized loss positions	461,400
Available for sale securities gross unrealized loss positions greater than 12 months	$ 92,700
Number of available-for-sale securities | Security	63
Accrued interest receivable on available-for-sale securities	$ 1,500	$ 1,100

Fair Value Measurements - Sched

Fair Value Measurements - Schedule Of Fair Value Measurements, By Major Security Type (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	$ 485,616	$ 386,639
Fair Value Measurements on Recurring Basis
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	30,762
Short-term investments	485,616	386,639
Cash equivalents and short-term investments	516,378	400,229
Fair Value Measurements on Recurring Basis | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	30,762
Short-term investments	430,821	300,214
Cash equivalents and short-term investments	461,583	313,804
Fair Value Measurements on Recurring Basis | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	54,795	86,425
Cash equivalents and short-term investments	54,795	86,425
Fair Value Measurements on Recurring Basis | Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	22,800	13,590
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	22,800	13,590
Fair Value Measurements on Recurring Basis | U.S. Treasury Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	7,962
Short-term investments	430,821	300,214
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]
Cash equivalents	7,962
Short-term investments	430,821	300,214
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	39,901	63,770
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	39,901	63,770
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	14,894	14,727
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	$ 14,894	14,727
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		7,928
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		$ 7,928

Balance Sheet Detail - Summary

Balance Sheet Detail - Summary of Property and Equipment (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 4,369	$ 4,311
Less: accumulated depreciation	(2,660)	(2,452)
Property and equipment, net	1,709	1,859
Laboratory and Computer Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	1,632	1,657
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	$ 1,194	$ 1,111

Balance Sheet Detail - Summar_2

Balance Sheet Detail - Summary of Current Accrued Expenses (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Accrued Liabilities, Current [Abstract]
Accounts payable	$ 7,529	$ 2,300
Accrued clinical trial research and development expenses	7,381	7,737
Accrued other research and development expenses	6,262	9,265
Accrued compensation and benefits	6,058	13,153
Other accrued expenses	3,673	1,302
Total accounts payable and accrued expenses	$ 30,903	$ 33,757

Leases - Additional Information

Leases - Additional Information (Detail)	1 Months Ended	3 Months Ended
	Aug. 31, 2023 USD ($)	Mar. 31, 2024 USD ($) Lease	Mar. 31, 2023 USD ($)	Dec. 31, 2023
Lessee Lease Description [Line Items]
Number of operating leases | Lease		3
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 August 2025 and July 2031.
Number of leases that include renewal option | Lease		2
Lease agreement additional extended lease term		5 years
Weighted-average discount rate		10.60%		10.40%
Weighted-average remaining lease term		6 years 1 month 6 days		6 years 2 months 12 days
Total cash paid for amounts included in the measurement of lease liabilities		$ 500,000	$ 600,000
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
San Diego Corporate Headquarters Lease
Lessee Lease Description [Line Items]
Reimbursements for tenant improvements		1,000,000
Office Lease in Boston | Letter of Credit
Lessee Lease Description [Line Items]
Letter of Credit		200,000
San Diego Lease for Lab and Office Space
Lessee Lease Description [Line Items]
Reimbursements for tenant improvements		$ 100,000
Boston Lease
Lessee Lease Description [Line Items]
Lessee, operating lease, option to extend, description	In August 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
Lease agreement additional extended lease term	7 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
Lease 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	Mar. 31, 2024 USD ($)
Leases [Abstract]
2024 (remaining)	$ 1,081
2025	1,964
2026	1,344
2027	1,371
2028	1,398
Thereafter	3,740
Total lease payments	10,898
Less: imputed interest	(3,304)
Total operating lease liabilities	$ 7,594

Stockholder's Equity - Addition

Stockholder's Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended
	Jan. 26, 2024	Mar. 31, 2024
Class of Stock [Line Items]
Common stock, shares issued	1,376,813
Common stock, issued purchase price per share	$ 17.25
Net proceeds from the private placement, after deducting expenses	$ 145,800	$ 145,814
Pre-funded Warrants
Class of Stock [Line Items]
Common stock, issued purchase price per share	$ 17.25
Pre-funded warrants issued	7,318,886
Pre-funded warrants issued price per warrants	$ 17.2499
Pre-funded warrants exercise price per share	$ 0.0001

Share-Based Compensation - Addi

Share-Based Compensation - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2024	Dec. 31, 2023
Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized estimated stock option compensation expenses	$ 49.4
Weighted average period remaining for amortization of unrecognized compensation cost	2 years 8 months 12 days
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized estimated restricted stock units compensation expenses	$ 16.9
Weighted average period remaining for amortization of unrecognized compensation cost	2 years 9 months 18 days
Performance Based Restricted Stock Units
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
	Mar. 31, 2024	Mar. 31, 2023
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense	$ 8,512	$ 6,838
Research and development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense	3,885	3,073
General and administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense	$ 4,627	$ 3,765