0001789769-24-000103 | 10-Q | XBRL Viewer

Stock-Based Compensation

9 Months Ended

Sep. 30, 2024

Share-Based Payment Arrangement [Abstract]

2021 Equity Incentive Plan

In March 2021, the Company adopted the 2021 Equity Incentive Plan (the “2021 Plan”), which became effective in connection with the Company’s initial public offering (“IPO”). The 2021 Plan was approved by the Board of Directors and stockholders in March 2021. The 2021 Plan is an equity incentive plan pursuant to which the Company may grant the following awards: (i) incentive stock options; (ii) nonstatutory stock options; (iii) stock appreciation rights; (iv) restricted stock awards; (v) restricted stock unit awards; (vi) performance awards; and (vii) other forms of stock awards to employees, directors, and consultants, including employees and consultants of the Company’s affiliates. The 2021 Plan is a successor to the Company’s 2018 Stock Incentive Plan (the “2018 Plan”). Following the effectiveness of the 2021 Plan, no further grants may be made under the 2018 Plan; however, any outstanding equity awards granted under the 2018 Plan will continue to be governed by the terms of the 2018 Plan.

As of September 30, 2024, 185,883 shares of common stock remained available for issuance under the 2021 Plan. As of September 30, 2024, the total number of shares authorized for issuance under the 2021 Plan was 642,722 shares.

The following table sets forth stock-based compensation included in the Company’s statement of operations and comprehensive loss (in thousands):


	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2024		2023		2024		2023
Research and development expense	$	506	$	567	$	1,587	$	999
General and administrative expense	3,562		4,103		11,169		12,614
Total stock-based compensation expense	$	4,068	$	4,670	$	12,756	$	13,613

As of September 30, 2024, there was $21.3 million of total unrecognized compensation cost related to unvested stock options granted under the 2018 Plan and 2021 Plan, which is expected to be recognized over a weighted average period of 2.2 years.

Employee Stock Purchase Plan

In March 2021, the Company adopted the Employee Stock Purchase Plan (the “ESPP”), which became effective in connection with the IPO. The ESPP was adopted by the Board of Directors and stockholders in March 2021, but the Company has not yet commenced offerings to employees under the ESPP. The ESPP initially provides participating employees with the opportunity to purchase up to an aggregate of 61,850 shares of common stock. The number of shares reserved under the ESPP automatically increases on January 1 of each year through and until January 1, 2031, in an amount equal to the lesser of (i) 1% of the total number of shares of common stock outstanding on December 31 of the preceding calendar year, and (ii) 123,700 shares; provided, however, that before the date of any such increase, the Board of Directors may determine that such increase will be less than the amount set forth in clauses (i) and (ii).

Financial Instruments (Tables)

9 Months Ended

Sep. 30, 2024

Investments, Debt and Equity Securities [Abstract]

Schedule of Marketable Securities and Long-Term Investments

Marketable securities and long-term investments classified as available-for-sale on September 30, 2024 and December 31, 2023 consisted of the following (in thousands):


	September 30, 2024
	Maturity	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
U.S. Treasury bills	Less than one year	$	113,496	$	194	$	—	$	113,690
U.S. Treasury bills	Between one and two years	2,559		—		(2)		2,557
Total		$	116,055	$	194	$	(2)	$	116,247


	December 31, 2023
	Maturity	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
U.S. Treasury bills	Less than one year	$	141,075	$	86	$	—	$	141,161
U.S. Treasury bills	Between one and two years	23,134		27		—		23,161
Total		$	164,209	$	113	$	—	$	164,322

- Definition

Tabular disclosure of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

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-Topic 320
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+ Details

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Cash flows from operating activities:
Net loss	$ (62,240)	$ (143,162)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	12,756	13,613
Non-cash lease expense	174	610
Foreign exchange remeasurement gain	(278)	(147)
Impairment of fixed assets	4,285	60,088
Impairment of right-of-use assets	827	7,724
Change in fair value of contingent consideration	(2,500)	(41)
Depreciation	2,869	3,720
In-process research and development expenses	10,000	0
Accretion on invested securities	(3,861)	(4,716)
Non-cash interest expense	754	762
Change in fair value of derivative financial instrument	265	528
Loss on disposals of property and equipment	343	338
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(4,033)	(1,082)
Other long-term assets	(3,115)	275
Accounts payable	(34)	(652)
Operating lease liabilities	(995)	(1,198)
Long term liabilities	0	(12)
Accrued expenses and other current liabilities	(354)	(5,296)
Net cash used in operating activities	(45,137)	(68,648)
Cash flows from investing activities:
Purchase of marketable securities	(106,684)	(250,517)
Maturities of marketable securities	158,700	298,300
Purchases of property, plant and equipment	0	(20,605)
Cash received from held for sale assets	546	0
Acquired in-process research and development	(10,000)	0
Purchase of derivative financial instrument	(1,588)	0
Net cash provided by investing activities	40,974	27,178
Cash flows from financing activities:
Principal payments on loan	0	(587)
Proceeds from exercise of stock options	159	0
Proceeds from note payable	0	8,669
Net cash provided by financing activities	159	8,082
Net decrease in cash, cash equivalents and restricted cash	(4,004)	(33,388)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(29)	(182)
Cash, cash equivalents and restricted cash—beginning of period	10,696	43,716
Cash, cash equivalents and restricted cash—end of period	6,663	10,146
Supplemental disclosure of cash flow information:
Cash paid for interest, net of amounts capitalized	5,241	4,908
Supplemental disclosure of noncash information:
Purchases of property, plant and equipment in accounts payable and accrued expenses and other current liabilities	$ 0	$ 67

Summary of Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2024

Accounting Policies [Abstract]

Schedule of Cash, Cash Equivalents and Restricted Cash

The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the condensed consolidated balance sheets that sum to the amounts shown in the condensed consolidated statements of cash flows (in thousands):


	September 30, 2024		December 31, 2023
Cash and cash equivalents	$	6,663	$	9,195
Restricted cash	—		1,501
Cash, cash equivalents and restricted cash	$	6,663	$	10,696

Schedule of Cash, Cash Equivalents and Restricted Cash


	September 30, 2024		December 31, 2023
Cash and cash equivalents	$	6,663	$	9,195
Restricted cash	—		1,501
Cash, cash equivalents and restricted cash	$	6,663	$	10,696

Balance Sheet Components - Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accrued compensation and benefits	$ 2,401	$ 1,026
Accrued operational expenses	957	1,412
Accrued restructuring costs	3,453	3,136
Accrued research, development and clinical trial expenses	$ 406	$ 1,833
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Total accrued expenses and other current liabilities	Total accrued expenses and other current liabilities
Operating lease liabilities, current	$ 1,761	$ 1,750
Other current liabilities	107	190
Total accrued expenses and other current liabilities	$ 9,085	$ 9,347

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023
Pay vs Performance Disclosure
Net loss	$ (23,021)	$ (14,917)	$ (24,302)	$ (67,432)	$ (18,662)	$ (57,068)	$ (62,240)	$ (143,162)

- Definition

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

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+ Details

Commitments and Contingencies - Lease Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Operating lease cost	$ 172	$ 351	$ 1,097	$ 1,867
Variable lease cost	283	234	649	906
Total lease cost	455	585	1,746	2,773
Cash paid for operating lease liabilities	494	$ 491	1,756	$ 1,806
Operating lease right-of-use assets	1,104		1,104		$ 2,387
Current operating lease liabilities	1,761		1,761		1,750
Non-current operating lease liabilities	$ 1,411		$ 1,411		$ 2,877
Weighted-average remaining lease term (in years)	1 year 11 months 4 days		1 year 11 months 4 days		2 years 7 months 6 days
Weighted-average discount rate	6.75%		6.75%		6.75%

Equity	9 Months Ended
Equity	Sep. 30, 2024
Equity [Abstract]
Equity	Equity Common Stock Each share of common stock has the right to one vote. The holders of common stock are also entitled to receive dividends whenever funds are legally available and if declared by the Company’s Board of Directors (the “Board of Directors”), subject to the prior rights of holders of all classes of stock outstanding having priority rights as to dividends. No cash dividends have been declared by the Board of Directors from inception. As of September 30, 2024 and December 31, 2023, the Company had 6,525,266 and 6,503,913 shares of common stock outstanding, respectively. Preferred Stock Activity The Company’s current amended and restated certificate of incorporation authorizes the Company to issue up to 10,000,000 shares of preferred stock at $0.000001 par value per share. The Board of Directors is authorized to provide for the issuance of the preferred stock in one or more series, and to fix the number of shares and to determine or alter for each such series, such voting powers, full or limited, or no voting powers, and such designation, preferences, and relative, participating, optional, or other rights and such qualifications, limitations, or restrictions thereof, as shall be stated and expressed in subsequent resolution or resolutions adopted by the board providing for the issuance of such shares. As of September 30, 2024 and December 31, 2023, there were no shares of preferred stock issued or outstanding.

- Definition

The entire disclosure for equity.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-13

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (h)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-13

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-14

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 235
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477968/946-235-50-2

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 235
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477968/946-235-50-2

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478448/946-505-50-6

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480237/815-40-50-6

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480008/505-10-S99-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(e)(1))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-1

Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 505
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org/505/tableOfContent

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-13

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (g)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-13

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (i)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-13

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-14

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-14

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 16
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-16

Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 18
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-18

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 18
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-18

Reference 19: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 18
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-18

+ Details

Corporate Restructuring Plan - Schedule of Realignment Non-cash Charges (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2024 USD ($)
Restructuring Reserve [Roll Forward]
Restructuring liability, balance at beginning of period	$ 3,136
Restructuring liability, balance at end of period	3,453
2023 Plan
Restructuring Reserve [Roll Forward]
Restructuring liability, balance at beginning of period	3,136
Additions, net	3,115
Payments	(1,449)
Adjustments	(1,349)
Restructuring liability, balance at end of period	3,453
Employee Benefits \| 2023 Plan
Restructuring Reserve [Roll Forward]
Restructuring liability, balance at beginning of period	0
Additions, net	2,395
Payments	(978)
Adjustments	0
Restructuring liability, balance at end of period	1,417
Contract Terminations \| 2023 Plan
Restructuring Reserve [Roll Forward]
Restructuring liability, balance at beginning of period	3,136
Additions, net	720
Payments	(471)
Adjustments	(1,349)
Restructuring liability, balance at end of period	$ 2,036

Summary of Significant Accounting Policies - Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023	Sep. 30, 2023	Dec. 31, 2022
Accounting Policies [Abstract]
Cash and cash equivalents	$ 6,663	$ 9,195
Restricted cash	0	1,501
Cash, cash equivalents and restricted cash	$ 6,663	$ 10,696	$ 10,146	$ 43,716

Net Loss Per Share (Tables)

9 Months Ended

Sep. 30, 2024

Earnings Per Share [Abstract]

Schedule of Antidilutive Securities Excluded from Calculation of Diluted Net Loss per Share

The following outstanding potentially dilutive shares have been excluded from the calculation of diluted net loss per share for the periods presented due to their anti-dilutive effect:


	September 30,
	2024	2023
Stock options to purchase common stock	1,251,394	868,753

Balance Sheet Components

9 Months Ended

Sep. 30, 2024

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Balance Sheet Components

Prepaid and other current assets

Prepaid and other current assets consist of the following (in thousands):


	September 30, 2024		December 31, 2023
Prepaid general and administration	$	1,397	$	1,033
Prepaid research and development	4,870		300
Other receivable	2,915		3,643
Prepaid contract research organization expenses	443		1,322
Other current assets	1,958		2,604
Total prepaid and other current assets	$	11,583	$	8,902

Property, Plant and Equipment, Net

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


	September 30, 2024		December 31, 2023
Land	$	31,243	$	31,243
Laboratory equipment	—		8,291
Buildings	102,433		102,433
Office and computer equipment	509		831
Leasehold improvements	—		1,424
Manufacturing equipment	—		2,017
Total property, plant and equipment, gross	134,185		146,239
Less: accumulated depreciation	(4,038)		(7,555)
Total property, plant and equipment, net	$	130,147	$	138,684

Depreciation expense was $0.9 million and $1.0 million for the three months ended September 30, 2024 and 2023, respectively, and was $2.9 million and $3.7 million for the nine months ended September 30, 2024 and 2023, respectively, in the condensed consolidated statements of operations and comprehensive loss.

The Company capitalized interest of nil during the three months ended September 30, 2024 and 2023, while during the nine months ended September 30, 2024 and 2023, the Company capitalized nil and $2.4 million, respectively, of interest related to qualifying expenditures for construction work-in-progress for its Tarzana manufacturing facility.

Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consist of the following (in thousands):


	September 30, 2024		December 31, 2023
Accrued compensation and benefits	$	2,401	$	1,026
Accrued operational expenses	957		1,412
Accrued restructuring costs	3,453		3,136
Accrued research, development and clinical trial expenses	406		1,833
Operating lease liabilities, current	1,761		1,750
Other current liabilities	107		190
Total accrued expenses and other current liabilities	$	9,085	$	9,347

Commitments and Contingencies - Schedule of Future Fixed Contractual Lease Payments to be Received (Details) $ in Thousands	Sep. 30, 2024 USD ($)
Commitments and Contingencies Disclosure [Abstract]
2024 (remaining three months)	$ 1,493
2025	8,957
2026	8,957
2027	8,957
2028	8,957
Thereafter	94,795
Total	$ 132,116

Fair Value Measurement - Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Financial Assets
U.S. Treasury bills	$ 113,690	$ 141,161
Fair Value, Recurring
Financial Assets
Derivative financial instrument	790	1,055
Total	120,312	171,061
Financial Liabilities
Contingent consideration	2,358	4,858
Fair Value, Recurring \| U.S. Treasury bills
Financial Assets
U.S. Treasury bills	116,247	164,322
Level 1 \| Fair Value, Recurring
Financial Assets
Derivative financial instrument	0	0
Total	3,275	5,684
Financial Liabilities
Contingent consideration	0	0
Level 1 \| Fair Value, Recurring \| U.S. Treasury bills
Financial Assets
U.S. Treasury bills	0	0
Level 2 \| Fair Value, Recurring
Financial Assets
Derivative financial instrument	790	1,055
Total	117,037	165,377
Financial Liabilities
Contingent consideration	0	0
Level 2 \| Fair Value, Recurring \| U.S. Treasury bills
Financial Assets
U.S. Treasury bills	116,247	164,322
Level 3 \| Fair Value, Recurring
Financial Assets
Derivative financial instrument	0	0
Total	0	0
Financial Liabilities
Contingent consideration	2,358	4,858
Level 3 \| Fair Value, Recurring \| U.S. Treasury bills
Financial Assets
U.S. Treasury bills	0	0
Money market funds \| Fair Value, Recurring
Financial Assets
Money market funds	3,275	5,684
Money market funds \| Level 1 \| Fair Value, Recurring
Financial Assets
Money market funds	3,275	5,684
Money market funds \| Level 2 \| Fair Value, Recurring
Financial Assets
Money market funds	0	0
Money market funds \| Level 3 \| Fair Value, Recurring
Financial Assets
Money market funds	$ 0	$ 0

Commitments and Contingencies - Future Minimum Payments (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2024 (remaining three months)	$ 735
2025	1,591
2026	1,195
Total future lease payments	3,521
Less: imputed interest	349
Total lease liability balance	3,172
Less: current portion of operating lease liabilities	1,761	$ 1,750
Total operating lease liabilities, non-current	$ 1,411	$ 2,877

Corporate Restructuring Plan (Tables)

9 Months Ended

Sep. 30, 2024

Restructuring and Related Activities [Abstract]

Schedule of Total Amount Expected to be Incurred and Liability

The following table summarizes the restructuring and impairment charges by category (in thousands):


	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2024		2023		2024		2023
Asset impairment for leasehold improvements	$	51	$	—	$	343	$	2,644
One-time employee termination benefits	1,449		41		2,427		1,816
Building and construction work in progress impairment	—		41,542		—		41,542
Contract terminations	(1,282)		—		(736)		1,888
Right-of-use asset impairment	640		128		827		7,724
Impairment of long-lived assets held for sale	1,504		4,572		4,285		16,233
Total restructuring and impairment charges	$	2,362	$	46,283	$	7,146	$	71,847

Schedule of Realignment Non-cash Charges

The following table shows the liability related to the Plan (in thousands):


	Employee Benefits		Contract Terminations		Total
Restructuring liability as of December 31, 2023	$	—	$	3,136	$	3,136
Additions, net	2,395		720		3,115
Payments	(978)		(471)		(1,449)
Adjustments	—		(1,349)		(1,349)
Total restructuring liability as of September 30, 2024	$	1,417	$	2,036	$	3,453

License and Collaboration Agreement with ImmuneOnco	9 Months Ended
License and Collaboration Agreement with ImmuneOnco	Sep. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
License and Collaboration Agreement with ImmuneOnco	License and Collaboration Agreement with ImmuneOnco On August 1, 2024, SynBioTx and ImmuneOnco entered into the IO Collaboration Agreement pursuant to which SynBioTx in-licensed certain bispecific antibodies, including SYN-2510/IMM2510 and SYN-27M/IMM27M from ImmuneOnco. Pursuant the IO Collaboration Agreement, SynBioTx paid ImmuneOnco a $10.0 million upfront payment and prepaid ImmuneOnco $5.0 million in development costs in the quarter ended September 30, 2024. ImmuneOnco is eligible to receive additional potential near-term payments of up to $35.0 million, up to $2.1 billion in commercial, development and regulatory milestones (including up to $270.0 million in longer term development and regulatory milestones and up to $1.8 billion in commercial milestones) plus single-digit to low double-digit percentage royalties on global net sales of the licensed products outside of Greater China. The expenses recognized in connection with the IO Collaboration Agreement were $10.0 million and nil for the three and nine months ended September 30, 2024 and 2023, respectively, recorded as a component of In-process research and development on the condensed consolidated statement of operations and comprehensive loss. As of September 30, 2024, no additional milestones had been accrued as the underlying contingencies had not yet been resolved.

Balance Sheet Components - Schedule Of Prepaid and Other Current Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Prepaid general and administration	$ 1,397	$ 1,033
Prepaid research and development	4,870	300
Other receivable	2,915	3,643
Prepaid contract research organization expenses	443	1,322
Other current assets	1,958	2,604
Total prepaid and other current assets	$ 11,583	$ 8,902

Stock-Based Compensation - Narrative (Details) - USD ($) $ in Millions	1 Months Ended	9 Months Ended
	Mar. 31, 2021	Sep. 30, 2024
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future issuance (in shares)		185,883
Shares authorized (in shares)		642,722
Unrecognized compensation cost		$ 21.3
Unrecognized compensation cost, recognition period		2 years 2 months 12 days
Minimum number of additional shares to be authorized (in shares)	123,700
Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized (in shares)	61,850
Percentage of outstanding capital stock	1.00%

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 35
-Paragraph 1D
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480483/718-10-35-1D

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 35
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480483/718-10-35-3

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(ii)
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-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iii)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(01)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(02)
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-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(03)
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-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Name Accounting Standards Codification
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-Paragraph 2
-Subparagraph (c)(1)(iv)(04)
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-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
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Reference 15: http://www.xbrl.org/2003/role/disclosureRef
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Reference 16: http://www.xbrl.org/2003/role/disclosureRef
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Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Name Accounting Standards Codification
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-Paragraph 2
-Subparagraph (c)(2)(iii)(01)
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Reference 19: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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Reference 20: http://www.xbrl.org/2003/role/disclosureRef
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Reference 24: http://www.xbrl.org/2003/role/disclosureRef
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-Topic 718
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-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
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-Subparagraph (f)(2)(iii)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

Reference 27: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Name Accounting Standards Codification
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-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

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-Topic 718
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-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(v)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

+ Details

Balance Sheet Components (Tables)

9 Months Ended

Sep. 30, 2024

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule of Prepaid Expenses and Other Current Assets

Prepaid and other current assets consist of the following (in thousands):


	September 30, 2024		December 31, 2023
Prepaid general and administration	$	1,397	$	1,033
Prepaid research and development	4,870		300
Other receivable	2,915		3,643
Prepaid contract research organization expenses	443		1,322
Other current assets	1,958		2,604
Total prepaid and other current assets	$	11,583	$	8,902

Schedule of Property, Plant and Equipment, Net

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


	September 30, 2024		December 31, 2023
Land	$	31,243	$	31,243
Laboratory equipment	—		8,291
Buildings	102,433		102,433
Office and computer equipment	509		831
Leasehold improvements	—		1,424
Manufacturing equipment	—		2,017
Total property, plant and equipment, gross	134,185		146,239
Less: accumulated depreciation	(4,038)		(7,555)
Total property, plant and equipment, net	$	130,147	$	138,684

Schedule of Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consist of the following (in thousands):


	September 30, 2024		December 31, 2023
Accrued compensation and benefits	$	2,401	$	1,026
Accrued operational expenses	957		1,412
Accrued restructuring costs	3,453		3,136
Accrued research, development and clinical trial expenses	406		1,833
Operating lease liabilities, current	1,761		1,750
Other current liabilities	107		190
Total accrued expenses and other current liabilities	$	9,085	$	9,347

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Sep. 30, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.000001	$ 0.000001
Preferred stock authorized (in shares)	10,000,000	10,000,000
Preferred stock issued (in shares)	0	0
Preferred stock outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.000001	$ 0.000001
Common stock, shares authorized (in shares)	300,000,000	300,000,000
Common stock, shares issued (in shares)	6,525,266	6,503,913
Common stock, shares outstanding (in shares)	6,525,266	6,503,913

Corporate Restructuring Plan - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment charges	$ 2,362	$ 46,283	$ 7,146	$ 71,847
Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring and impairment charges	2,362	$ 46,283	7,146	$ 71,847
Expected restructuring costs remaining	500		500
Restructuring charges	$ 0		$ 1,400

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References + Details

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Operating expenses:
In-process research and development	$ 10,000	$ 0	$ 10,000	$ 0
Research and development	562	8,492	10,739	37,621
General and administrative	10,707	11,941	33,837	36,681
Restructuring and impairment charges	2,362	46,283	7,146	71,847
Total operating expenses	23,631	66,716	61,722	146,149
Loss from operations	(23,631)	(66,716)	(61,722)	(146,149)
Interest income	1,654	2,313	5,635	6,671
Interest expense	(2,007)	(2,003)	(5,988)	(3,229)
Other rental income	1,493	0	1,493	0
Other expense, net	(530)	(1,026)	(1,658)	(455)
Net loss	(23,021)	(67,432)	(62,240)	(143,162)
Other comprehensive loss:
Foreign currency translation	(291)	231	(252)	(210)
Unrealized gain on available-for-sale securities, net	398	39	80	178
Net comprehensive loss	$ (22,914)	$ (67,162)	$ (62,412)	$ (143,194)
Net loss per share, basic (in dollars per share)	$ (3.54)	$ (10.37)	$ (9.57)	$ (22.01)
Net loss per share, diluted (in dollars per share)	$ (3.54)	$ (10.37)	$ (9.57)	$ (22.01)
Weighted-average shares used in computing net loss per share, basic (in shares)	6,506,681	6,503,913	6,504,842	6,503,913
Weighted-average shares used in computing net loss per share, diluted (in shares)	6,506,681	6,503,913	6,504,842	6,503,913

Equity (Details)	Sep. 30, 2024 vote $ / shares shares	Dec. 31, 2023 $ / shares shares
Equity [Abstract]
Common stock, votes per share \| vote	1
Common stock, shares outstanding (in shares)	6,525,266	6,503,913
Preferred stock authorized (in shares)	10,000,000	10,000,000
Common stock, par value (in dollars per share) \| $ / shares	$ 0.000001	$ 0.000001
Convertible preferred stock issued (in shares)	0	0

Balance Sheet Components - Property, Plant and Equipment, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	$ 134,185	$ 146,239
Less: accumulated depreciation	(4,038)	(7,555)
Total property, plant and equipment, net	130,147	138,684
Land
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	31,243	31,243
Laboratory equipment
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	0	8,291
Buildings
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	102,433	102,433
Office and computer equipment
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	509	831
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	0	1,424
Manufacturing equipment
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	$ 0	$ 2,017

Financial Instruments - Schedule of Marketable Securities and Long-Term Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Amortized Cost
Total	$ 116,055	$ 164,209
Unrealized Gains
Total	194	113
Unrealized Losses
Total	(2)	0
Fair Value
Total	116,247	164,322
U.S. Treasury bills
Amortized Cost
Less than one year	113,496	141,075
Between one and two years	2,559	23,134
Unrealized Gains
Less than one year	194	86
Between one and two years	0	27
Unrealized Losses
Less than one year	0	0
Between one and two years	(2)	0
Fair Value
Less than one year	113,690	141,161
Between one and two years	$ 2,557	$ 23,161

Net Loss Per Share (Details) - shares	9 Months Ended
Net Loss Per Share (Details) - shares	Sep. 30, 2024	Sep. 30, 2023
Stock options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares (in shares)	1,251,394	868,753

Cover - shares	9 Months Ended
Cover - shares	Sep. 30, 2024	Nov. 11, 2024
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2024
Document Transition Report	false
Entity File Number	001-40215
Entity Registrant Name	Instil Bio, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	83-2072195
Entity Address, Address Line One	3963 Maple Avenue, Suite 350
Entity Address, City or Town	Dallas
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	75219
City Area Code	972
Local Phone Number	499-3350
Title of 12(b) Security	Common Stock, $0.000001 par value per share
Trading Symbol	TIL
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		6,525,887
Amendment Flag	false
Entity Central Index Key	0001789769
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	Q3
Document Fiscal Year Focus	2024

Summary of Significant Accounting Policies (Policies)	9 Months Ended
Summary of Significant Accounting Policies (Policies)	Sep. 30, 2024
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and include the accounts of the Company and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. The unaudited condensed consolidated financial statements have been prepared on the same basis as the audited annual consolidated financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair statement of the Company’s financial position as of September 30, 2024, the condensed consolidated statements of operations and comprehensive loss for the three and nine months ended September 30, 2024 and 2023, the condensed consolidated statements of stockholders’ equity for the three and nine months ended September 30, 2024 and 2023, and the results of its cash flows for the nine months ended September 30, 2024 and 2023. The financial data and other information disclosed in these notes related to the three and nine months ended September 30, 2024 and 2023 are also unaudited. The results for the three and nine months ended September 30, 2024 are not necessarily indicative of results to be expected for the year ending December 31, 2024, any other periods, or any future year period. The Company has evaluated subsequent events through the date the condensed consolidated financial statements were issued. The accompanying unaudited condensed consolidated financial statements should be read in conjunction with the audited financial statements and the related notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023, as filed with the Securities and Exchange Commission (“SEC”) on March 21, 2024.
Segments	Segments Operating segments are identified as components of an entity for which separate discrete financial information is available and that is regularly reviewed by the chief operating decision-maker in deciding how to allocate resources to an individual segment and in assessing performance. The Company has determined it operates in a single operating segment and has one operating segment.
Cash, Cash Equivalents, Restricted Cash, Marketable Securities, and Long-Term Investments	Cash, Cash Equivalents, Restricted Cash, Marketable Securities, and Long-Term Investments The Company considers all highly liquid investments purchased with original maturities of three months or less from the purchase date to be cash equivalents. Cash equivalents include amounts invested in money market accounts. Restricted cash consists of a cash reserve which serves as collateral for the Company’s construction loan and is classified within current assets on the condensed consolidated balance sheet as of September 30, 2024. There was no restricted cash as of September 30, 2024 and $1.5 million of restricted cash as of December 31, 2023 on the condensed consolidated balance sheet.
Marketable Securities	The Company’s investments in marketable securities and long-term investments have been classified and accounted for as available-for-sale. The Company classifies its maturities as either short-term or long-term based on each instrument’s underlying contractual maturity date, which are carried at their fair values based on the quoted market prices of the securities. Unrealized gains and losses are reported as accumulated other comprehensive income (loss). Realized gains and losses on available-for-sale securities are included in net loss in the period earned or incurred. As of September 30, 2024 and December 31, 2023, marketable securities consisted of U.S. Treasury bills. The Company periodically reviews whether its securities may be other-than-temporarily impaired, including whether or not (i) the Company has the intent to sell the security or (ii) it is more likely than not that the Company will be required to sell the security before its anticipated recovery. If one of these factors is met, the Company will record an impairment loss associated with its impaired investment. The impairment loss will be recorded as a write-down of investments in the condensed consolidated balance sheets and a realized loss within other expense in the condensed consolidated statements of operations and comprehensive loss.
Assets Held for Sale	Assets Held for Sale The Company classifies long-lived assets or disposal groups to be sold as held for sale in the period in which all of the following criteria are met: management, having the authority to approve the action, commits to a plan to sell the asset or disposal group; the asset or disposal group is available for immediate sale in its present condition subject only to terms that are usual and customary for sales of such assets or disposal group; the sale of the asset or disposal group is probable, and transfer of the asset or disposal group is expected to qualify for recognition as a completed sale within one year, except if events or circumstances beyond the Company’s control extend the period of time required to sell the asset or disposal group beyond one year; the asset or disposal group is being actively marketed for sale at a price that is reasonable in relation to its current fair value; and actions required to complete the plan to sell have been initiated. The Company initially measures a long-lived asset or disposal group that is held for sale at the lower of its carrying value or fair value less any costs to sell. Fair value is estimated by the Company through evaluations of quoted market prices received for other comparable held for sale assets sold by the Company. Any loss resulting from this measurement is recognized in the period in which the held for sale criteria are met. Conversely, gains are not recognized on the sale of a long-lived asset or disposal group until the date of sale. The Company assesses the fair value of a long-lived asset or disposal group less any costs to sell each reporting period it remains classified as held for sale and reports any subsequent changes as an adjustment to the carrying value of the asset or disposal group, as long as the new carrying value does not exceed the carrying value of the asset at the time it was initially classified as held for sale. Upon determining that a long-lived asset or disposal group meets the criteria to be classified as held for sale, the Company ceases depreciation and reports long-lived assets in the line item “assets held for sale” in its condensed consolidated balance sheet.
Business Combinations	Business Combinations The Company evaluates acquisitions of assets and related liabilities and other similar transactions to assess whether or not the transaction should be accounted for as a business combination or asset acquisition by first applying a screen to determine if substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or group of similar identifiable assets. If the screen is met, the transaction is accounted for as an asset acquisition. If the screen is not met, further determination is required as to whether or not the Company has acquired inputs and processes that have the ability to create outputs which would meet the requirements of a business. The Company accounts for its business combinations using the acquisition method of accounting which requires recognition and measurement of all identifiable assets acquired and liabilities assumed at their full fair value as of the date it obtains control. The Company has determined the fair value of assets acquired and liabilities assumed based upon management’s estimates of the fair values of assets acquired and liabilities assumed in the acquisitions. Goodwill represents the excess of the purchase price over the fair value of the net tangible and identifiable intangible assets acquired. The Company accounts for contingent consideration at the acquisition-date fair value as part of the consideration transferred in the transaction. While management has used its best estimates and assumptions to measure the fair value of the identifiable assets acquired and liabilities assumed at the acquisition date, these estimates are inherently uncertain and subject to refinement. As a result, during the measurement period, not to exceed one year from the date of acquisition, any changes in the estimated fair values of the net assets recorded for the acquisitions will result in an adjustment to goodwill. Upon the conclusion of the measurement period or final determination of the values of assets acquired or liabilities assumed, whichever comes first, the Company records any subsequent adjustments to the consolidated statements of operations and comprehensive loss. Acquisition-related costs, such as legal and consulting fees, are expensed as incurred. The Company accounts for an asset acquisition by recognizing net assets based on the cost to the acquiring entity on a relative fair value basis, which includes transaction costs in addition to consideration given. Goodwill is not recognized in an asset acquisition; any excess consideration transferred over the fair value of the net assets acquired is allocated to the non-monetary identifiable assets and liabilities assumed based on relative fair values. Acquired in-process research and development is expensed as incurred provided there is no alternative future use.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company reviews its long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable or that the useful life is shorter than originally estimated. Recoverability of assets is measured by comparing the carrying amount of an asset to future undiscounted net cash flows expected to be generated by the asset over its remaining useful life. If such assets are impaired, the impairment recognized is measured by the amount by which the carrying amount of the assets exceeds the fair value of the assets. If the useful life is shorter than originally estimated, the Company depreciates or amortizes the remaining carrying value over the revised shorter useful life. Assets to be disposed of by sale are reflected at the lower of their carrying amount or fair value less costs to sell. To date, the Company has recorded impairment losses on long-lived assets associated with a sustained decrease in the Company’s stock price and in connection with the Plan as defined below in Note 11. The Company recognized a non-cash impairment charge of $0.1 million and $0.3 million during the three and nine months ended September 30, 2024, respectively, and nil and $2.6 million for the three and nine months ended September 30, 2023, respectively, related to leasehold improvements. Additionally, the Company recognized impairment charges of $41.5 million for the three and nine months ended September 30, 2023 relating to real estate. These impairment charges were recorded in the condensed consolidated statements of operations and comprehensive loss in the line item “restructuring and impairment charges.” See Notes 7 and 11 for more information.
Research and Development	Research and Development Research and development costs are expensed as incurred. Clinical trial and other development costs incurred by third parties are expensed as the contracted work is performed. The Company accrues for costs incurred as the services are being provided by monitoring the status of the trial or project and the invoices received from its external service providers. The Company adjusts its accrual as actual costs become known. Where contingent milestone payments are due to third parties under research and development arrangements or license agreements, the milestone payment obligations are expensed when the milestone results are achieved.
Recent Accounting Pronouncements Not Yet Adopted	Recent Accounting Pronouncements Not Yet Adopted In November 2023, the FASB issued ASU No. 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures which requires public entities to disclose information about their reportable segments’ significant expenses on an interim and annual basis. ASU 2023-07 is effective for annual periods beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024, with early adoption permitted. The Company is currently evaluating the impact of this ASU 2023-07 on its consolidated financial statements and related disclosures. In December 2023, the FASB issued ASU 2023-09 “Income Taxes (Topics 740): Improvements to Income Tax Disclosures” to expand the disclosure requirements for income taxes, specifically related to the rate reconciliation and income taxes paid. ASU 2023-09 is effective for annual periods beginning after December 15, 2024, with early adoption permitted. The Company is currently evaluating the impact of this ASU 2023-09 on its consolidated financial statements and related disclosures. In November 2024, the FASB issued ASU no. 2024-03, Income Statement-Reporting Comprehensive Income-Expense Disaggregation Disclosures (Subtopic 220-40). The amendments in this update require disclosure, in the notes to the financial statements, of specific expense categories present within expense captions presented on the face of the income statement within continuing operations of public business entities. The amendments in this update are effective for annual periods beginning after December 15, 2026 and interim periods beginning after December 15, 2027. A variety of proposed or otherwise potential accounting standards are currently being studied by standard-setting organizations and certain regulatory agencies. Because of the tentative and preliminary nature of such proposed standards, the Company has not yet determined the effect, if any, that the implementation of such proposed standards would have on its condensed consolidated financial statements.

Net Loss Per Share

9 Months Ended

Sep. 30, 2024

Earnings Per Share [Abstract]

Net Loss Per Share

The following outstanding potentially dilutive shares have been excluded from the calculation of diluted net loss per share for the periods presented due to their anti-dilutive effect:


	September 30,
	2024	2023
Stock options to purchase common stock	1,251,394	868,753

Fair Value Measurement (Tables)

9 Months Ended

Sep. 30, 2024

Fair Value Disclosures [Abstract]

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis

The following tables provide information by level for assets and liabilities that are measured at fair value on a recurring and nonrecurring basis:


	September 30, 2024
	Level 1		Level 2		Level 3		Total
	(In thousands)
Financial Assets
Money market funds	$	3,275	$	—	$	—	$	3,275
U.S. Treasury bills	—		116,247		—		116,247
Derivative financial instrument	—		790		—		790
Total	$	3,275	$	117,037	$	—	$	120,312
Financial Liabilities
Contingent consideration	$	—	$	—	$	2,358	$	2,358

	December 31, 2023
	Level 1		Level 2		Level 3		Total
	(In thousands)
Financial Assets
Money market funds	$	5,684	$	—	$	—	$	5,684
U.S. Treasury bills	—		164,322		—		164,322
Derivative financial instrument	—		1,055		—		1,055
Total	$	5,684	$	165,377	$	—	$	171,061
Financial Liabilities
Contingent consideration	$	—	$	—	$	4,858	$	4,858

Organization and Description of Business	9 Months Ended
Organization and Description of Business	Sep. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Description of Business	Organization and Description of Business Instil Bio, Inc. (the “Company”) is headquartered in Dallas, Texas and was incorporated in the state of Delaware in August 2018. The Company is a clinical-stage biopharmaceutical company focused on developing a pipeline of novel therapies. In particular, the Company seeks to in-license or acquire and develop novel therapeutic candidates in diseases with significant unmet medical need. In August 2024, the Company’s wholly owned subsidiary, SynBioTx, Inc. (“SynBioTx”), in-licensed certain bispecific antibodies, including SYN-2510/IMM2510, a bispecific antibody targeting both programmed death-ligand 1 (PD-L1) and vascular endothelial growth factor (VEGF), as well as SYN-27M/IMM27M, a monoclonal antibody targeting cytotoxic T-lymphocyte associated antigen 4 (CTLA-4), from ImmuneOnco Biopharmaceuticals (Shanghai) Inc. (“ImmuneOnco”). Pursuant to the license and collaboration agreement with ImmuneOnco (the “IO Collaboration Agreement”), SynBioTx has an exclusive license to research, develop, manufacture and commercialize these product candidates outside of China, including mainland China, Hong Kong, Macau and Taiwan (“Greater China”). ImmuneOnco retains development and commercialization rights in Greater China. The Company also has a proprietary (FRα) co-stimulatory antigen receptor (“CoStAR”) tumor infiltrating lymphocyte (“TIL”) cell therapy technology for the treatment of cancer, which the Company is seeking to advance via collaboration. In December 2023, the Company entered into an agreement with a third-party collaborator to develop an autologous FRα CoStAR TIL (the “CoStAR-TIL Collaboration Product”) for a potential investigator-initiated trial (“IIT”) in non-small cell lung cancer in China. The collaborator has an option to exclusively license the CoStAR-TIL Collaboration Product in China and Taiwan.

Stock-Based Compensation - Schedule of Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	$ 4,068	$ 4,670	$ 12,756	$ 13,613
Research and development expense
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	506	567	1,587	999
General and administrative expense
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	$ 3,562	$ 4,103	$ 11,169	$ 12,614

Commitments and Contingencies - Net Carrying Amount of the Liability Component of the Loan (Details) - Secured Mortgage Loan - Loans Payable - USD ($)	Sep. 30, 2024	Dec. 31, 2023	Jun. 30, 2022
Debt Instrument [Line Items]
Principal amount	$ 82,837,000	$ 82,837,000	$ 52,100,000
Unamortized debt issuance cost	(664,000)	(1,410,000)
Net carrying amount	$ 82,173,000	$ 81,427,000

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
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Reference 13: http://www.xbrl.org/2003/role/disclosureRef
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Reference 14: http://www.xbrl.org/2003/role/disclosureRef
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1D

Reference 17: http://www.xbrl.org/2003/role/disclosureRef
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-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1D
-Subparagraph (c)
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-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1D

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
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Reference 19: http://www.xbrl.org/2003/role/disclosureRef
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Reference 20: http://www.xbrl.org/2003/role/disclosureRef
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Reference 22: http://www.xbrl.org/2003/role/disclosureRef
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Reference 23: http://www.xbrl.org/2003/role/disclosureRef
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Reference 24: http://www.xbrl.org/2003/role/disclosureRef
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Reference 25: http://www.xbrl.org/2003/role/disclosureRef
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Reference 26: http://www.xbrl.org/2009/role/commonPracticeRef
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-Section 45
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Reference 27: http://www.xbrl.org/2009/role/commonPracticeRef
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-URI https://asc.fasb.org/1943274/2147482900/835-30-50-1

+ Details

- Definition

Amount, after deduction of unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation.

+ References + Details

Fair Value Measurement - Narrative (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Prepaid expenses and other current assets	Prepaid expenses and other current assets
Secured Mortgage Loan \| Level 2 \| Loans Payable
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of loan	$ 77.7

- Definition

Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2E
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2E

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 6: http://www.xbrl.org/2003/role/exampleRef
-Topic 470
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Reference 7: http://www.xbrl.org/2003/role/exampleRef
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
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-Subparagraph (c)
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-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1D

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482907/825-10-50-10

+ Details

Balance Sheet Components - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 0.9	$ 1.0	$ 2.9	$ 3.7
Construction in Progress
Property, Plant and Equipment [Line Items]
Interest related to qualifying expenditures	$ 0.0	$ 0.0	$ 0.0	$ 2.4

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 6,663	$ 9,195
Restricted cash	0	1,501
Marketable securities	113,690	141,161
Prepaid expenses and other current assets	11,583	8,902
Assets held for sale	637	0
Total current assets	132,573	160,759
Property, plant and equipment, net	130,147	138,684
Operating lease right-of-use assets	1,104	2,387
Long-term investments	2,557	23,161
Other long-term assets	6,181	639
Total assets	272,562	325,630
Current liabilities:
Accounts payable	1,195	1,212
Accrued expenses and other current liabilities	9,085	9,347
Total current liabilities	10,280	10,559
Contingent consideration, net of current portion	2,358	4,858
Operating lease liabilities, non-current	1,411	2,877
Loan payable	82,173	81,427
Other long-term liabilities	8	80
Total liabilities	96,230	99,801
Commitments and contingencies (Note 7)
Stockholders’ equity:
Preferred stock, par value $0.000001 per share; 10,000,000 shares authorized; zero shares issued and outstanding as of September 30, 2024, and December 31, 2023	0	0
Common stock, par value $0.000001 per share; 300,000,000 shares authorized; 6,525,266 and 6,503,913 shares issued and outstanding as of September 30, 2024, and December 31, 2023	0	0
Additional paid-in capital	820,073	807,158
Accumulated other comprehensive loss	(520)	(348)
Accumulated deficit	(643,221)	(580,981)
Total stockholders’ equity	176,332	225,829
Total liabilities and stockholders’ equity	$ 272,562	$ 325,630
Common stock, shares outstanding (in shares)	6,525,266	6,503,913
Common stock, shares issued (in shares)	6,525,266	6,503,913

Commitments and Contingencies - Schedule of Lease Income Related to the Operating Lease (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Commitments and Contingencies Disclosure [Abstract]
Other rental income	$ 1,493	$ 0	$ 1,493	$ 0

Financial Instruments - Narrative (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Investments, Debt and Equity Securities [Abstract]
U.S. Treasury bills	$ 113,690	$ 141,161
Long-term investments	$ 2,557	$ 23,161

- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 103
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482078/820-10-55-103

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Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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Reference 8: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
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-Paragraph 1
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
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-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479130/326-30-45-1

+ Details

Commitments and Contingencies - Interest Expense Related to the Loan (Details) - Secured Mortgage Loan - Loans Payable - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Interest Expense Related to the Loan [Line Items]
Contractual interest expense	$ 1,758	$ 1,754	$ 5,241	$ 2,482
Amortization of debt issuance cost	249	249	747	747
Total interest expense related to the Loan	$ 2,007	$ 2,003	$ 5,988	$ 3,229

Commitments and Contingencies

9 Months Ended

Sep. 30, 2024

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

Leases

Company as a Lessee: Operating Lease Obligations

The Company currently leases office spaces and laboratory spaces located in Greater Los Angeles, California, Dallas, Texas, and the United Kingdom. The Company’s leased facilities have original lease terms ranging from 2 to 5 years that predominately require the Company to provide a security deposit, while certain leases provide the right for the Company to renew the lease upon the expiration of the initial lease term, and various leases have scheduled rent increases on an annual basis. The exercise of lease renewal options for the Company’s existing leases is at the Company’s sole discretion, and not included in the measurement of right of use asset or lease liability as they are not reasonably certain to be exercised. Certain leases have leasehold improvements and are being amortized over the shorter of the estimated useful life of the improvements or the remaining life of the lease. Such improvements incurred by the Company will revert to the landlord at the expiration of the lease and will be removed from Company’s condensed consolidated balance sheets.

The Company’s lease costs consist of the following (in thousands):


	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2024		2023		2024		2023
Operating lease cost	$	172	$	351	$	1,097	$	1,867
Variable lease cost	283		234		649		906
Total lease cost	$	455	$	585	$	1,746	$	2,773

The following table summarizes cash flow information related to the Company’s lease obligations (in thousands):


	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2024		2023		2024		2023
Cash paid for operating lease liabilities	$	494	$	491	$	1,756	$	1,806

The following table summarizes the Company’s lease assets and liabilities (in thousands):


	September 30, 2024		December 31, 2023
Operating lease right-of-use assets	$	1,104	$	2,387
Current operating lease liabilities	$	1,761	$	1,750
Non-current operating lease liabilities	$	1,411	$	2,877

The following table summarizes other supplemental information related to the Company’s lease obligations:


	September 30, 2024		December 31, 2023
Weighted-average remaining lease term (in years)	1.93		2.60
Weighted-average discount rate	6.75	%	6.75	%

Future minimum lease payments under operating lease liabilities were (in thousands):


	September 30, 2024
2024 (remaining three months)	$	735
2025	1,591
2026	1,195
Total future lease payments	3,521
Less: imputed interest	349
Total lease liability balance	3,172
Less: current portion of operating lease liabilities	1,761
Total operating lease liabilities, non-current	$	1,411

During the nine months ended September 30, 2024 and 2023, the Company evaluated its remaining right-of-use assets for impairment, as the Plan (as defined below in Note 11) has resulted in a cessation of use for several locations. The Company determined these assets were impaired, and has recognized an impairment loss of $0.6 million and $0.1 million for the three months ended September 30, 2024 and 2023, respectively, and $0.8 million and $7.2 million for the nine months ended September 30, 2024 and 2023 respectively, which are recorded in the line item “restructuring and impairment charges” in the condensed consolidated statements of operations and comprehensive loss.

Company as Lessor: Tarzana Facility Lease with AstraZeneca

On July 10, 2024, Complex Therapeutics LLC entered into a lease (the “Lease”) with AstraZeneca Pharmaceuticals LP (“Tenant”) pursuant to which Tenant is leasing the Property located in Tarzana, CA. The Lease

has an initial term of approximately 15 years, beginning on July 10, 2024 (the “Commencement Date”) and ending on July 31, 2039, with Tenant having two consecutive options to extend the term for a five-year period each and a one-time option to terminate the Lease on the tenth anniversary of the Commencement Date, which, if exercised, obligates Tenant to pay Complex Therapeutics LLC a termination fee. The initial base rent is $0.6 million per month ($7.5 million annually) and the base rent will escalate by 3% per annum. Tenant is also required to pay certain operating expenses and tax expenses as additional rent. There is rent abatement during the first year of the Lease such that Tenant will pay no rent or reduced rent during this period. Tenant also has a right of first offer to purchase the premises that are subject to the Lease.

The Lease is classified as an operating lease and revenue will be recognized on a straight-line basis and will be recorded within the condensed consolidated statements of operations and comprehensive loss in the line item “Other rental income” as this is not a part of the Company’s core operations rental income has been presented in other income rather than as revenue on the statement of operations and comprehensive loss. Lease income related to the operating lease was as follows (in thousands):


	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2024		2023		2024		2023
Rental income related to fixed lease income	$	1,493	$	—	$	1,493	$	—

Approximate future fixed contractual lease payments to be received under a non-cancelable operating lease in effect as of September 30, 2024, are as follows (in thousands):


	September 30, 2024
2024 (remaining three months)	$	1,493
2025	8,957
2026	8,957
2027	8,957
2028	8,957
Thereafter	94,795
Total	$	132,116

Legal Proceedings

From time to time, the Company may have certain contingent liabilities that arise in the ordinary course of its business activities. The Company accrues a liability for such matters when it is probable that future expenditures will be made and that such expenditures can be reasonably estimated. Significant judgment is required to determine both probability and the estimated amount. The Company does not expect that the resolution of these matters will have a material adverse effect on its financial position, results of operations or cash flows.

Debt

In June 2022, the Company’s wholly owned subsidiary, Complex Therapeutics Mezzanine LLC, and the Company’s wholly owned indirect subsidiary, Complex Therapeutics LLC, entered into a mortgage construction loan and mezzanine construction loan (together, the “Loan”) secured by its Tarzana, California land and building (the “Property”). The initial principal amount of the Loan was $52.1 million, with additional future principal of up to $32.9 million to fund ongoing Property construction costs. Construction has been completed and on July 10, 2024, Complex Therapeutics LLC entered into the Lease. If the Company does not refinance or sell the Property prior to July 2025, when the Loan will be payable, the Company intends to use its option to extend the Loan until July 2026; the Company also has an another option to extend the Loan until July 2027. As of September 30, 2024, the outstanding principal amount under the Loan was $82.8 million and unamortized debt issuance costs were $0.7 million. During the year ended December 31, 2023, $0.6 million in additional principal was paid in accordance

with the Loan. The Loan is guaranteed by the Company and secured by the Property, and bears interest at the one-month Secured Overnight Financing Rate, plus 5.25% per annum. The Company discontinued capitalizing interest in June 2023 as the building was substantially complete at such time. The Loan contains customary negative and affirmative covenants that include limitations on the ability of the Company to enter into significant contracts and incur additional debt. The Company is also required to maintain consolidated net worth and liquid assets of at least $85.0 million as of September 30, 2024 and December 31, 2023 as defined in the loan agreement. As of September 30, 2024, the Company was in compliance with the covenants of the Loan. The Company is also required to maintain certain insurance coverage on the Property. In connection with the Loan, the Company entered into an interest rate swap to effectively limit its maximum interest rate, as discussed in Note 4.

The net carrying amount of the liability component of the Loan was as follows (in thousands):


	September 30, 2024		December 31, 2023
Principal amount	$	82,837	$	82,837
Unamortized debt issuance cost	(664)		(1,410)
Net carrying amount	$	82,173	$	81,427

The following table sets forth the interest expense recognized related to the Loan (in thousands):


	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2024		2023		2024		2023
Contractual interest expense	$	1,758	$	1,754	$	5,241	$	2,482
Amortization of debt issuance cost	249		249		747		747
Total interest expense related to the Loan	$	2,007	$	2,003	$	5,988	$	3,229

Other Commitments

In the normal course of business, the Company enters into contracts and various purchase agreements commitments with third-party vendors for clinical research services, products and other services from third parties for operating purposes. These agreements generally provide for termination or cancellation, other than for costs already incurred. As of September 30, 2024 and December 31, 2023, the Company had no outstanding liabilities, respectively, in commitments for employee benefits as part of the Plan. As of September 30, 2024 and December 31, 2023, the Company had $2.0 million and $3.1 million, respectively, in commitments for contract terminations as part of the Plan (see Note 11).

The Company has entered into an agreement with a third-party collaborator to develop the CoStAR-TIL Collaboration Product with the aim of enrolling patients in IITs in China. Milestone payments of $2.6 million were made during the nine months ended September 30, 2024 and were recorded within research and development expense in the condensed consolidated statements of operations and comprehensive loss, and upon successful completion of future milestones, the Company may be required to pay up to $3.4 million for clinical development.

Commitments and Contingencies

Leases

Company as a Lessee: Operating Lease Obligations

The Company’s lease costs consist of the following (in thousands):


	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2024		2023		2024		2023
Operating lease cost	$	172	$	351	$	1,097	$	1,867
Variable lease cost	283		234		649		906
Total lease cost	$	455	$	585	$	1,746	$	2,773

The following table summarizes cash flow information related to the Company’s lease obligations (in thousands):


	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2024		2023		2024		2023
Cash paid for operating lease liabilities	$	494	$	491	$	1,756	$	1,806

The following table summarizes the Company’s lease assets and liabilities (in thousands):


	September 30, 2024		December 31, 2023
Operating lease right-of-use assets	$	1,104	$	2,387
Current operating lease liabilities	$	1,761	$	1,750
Non-current operating lease liabilities	$	1,411	$	2,877

The following table summarizes other supplemental information related to the Company’s lease obligations:


	September 30, 2024		December 31, 2023
Weighted-average remaining lease term (in years)	1.93		2.60
Weighted-average discount rate	6.75	%	6.75	%

Future minimum lease payments under operating lease liabilities were (in thousands):


	September 30, 2024
2024 (remaining three months)	$	735
2025	1,591
2026	1,195
Total future lease payments	3,521
Less: imputed interest	349
Total lease liability balance	3,172
Less: current portion of operating lease liabilities	1,761
Total operating lease liabilities, non-current	$	1,411

Company as Lessor: Tarzana Facility Lease with AstraZeneca


	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2024		2023		2024		2023
Rental income related to fixed lease income	$	1,493	$	—	$	1,493	$	—

Approximate future fixed contractual lease payments to be received under a non-cancelable operating lease in effect as of September 30, 2024, are as follows (in thousands):


	September 30, 2024
2024 (remaining three months)	$	1,493
2025	8,957
2026	8,957
2027	8,957
2028	8,957
Thereafter	94,795
Total	$	132,116

Legal Proceedings

Debt

The net carrying amount of the liability component of the Loan was as follows (in thousands):


	September 30, 2024		December 31, 2023
Principal amount	$	82,837	$	82,837
Unamortized debt issuance cost	(664)		(1,410)
Net carrying amount	$	82,173	$	81,427

The following table sets forth the interest expense recognized related to the Loan (in thousands):


	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2024		2023		2024		2023
Contractual interest expense	$	1,758	$	1,754	$	5,241	$	2,482
Amortization of debt issuance cost	249		249		747		747
Total interest expense related to the Loan	$	2,007	$	2,003	$	5,988	$	3,229

Other Commitments

Commitments and Contingencies

Leases

Company as a Lessee: Operating Lease Obligations

The Company’s lease costs consist of the following (in thousands):


	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2024		2023		2024		2023
Operating lease cost	$	172	$	351	$	1,097	$	1,867
Variable lease cost	283		234		649		906
Total lease cost	$	455	$	585	$	1,746	$	2,773

The following table summarizes cash flow information related to the Company’s lease obligations (in thousands):


	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2024		2023		2024		2023
Cash paid for operating lease liabilities	$	494	$	491	$	1,756	$	1,806

The following table summarizes the Company’s lease assets and liabilities (in thousands):


	September 30, 2024		December 31, 2023
Operating lease right-of-use assets	$	1,104	$	2,387
Current operating lease liabilities	$	1,761	$	1,750
Non-current operating lease liabilities	$	1,411	$	2,877

The following table summarizes other supplemental information related to the Company’s lease obligations:


	September 30, 2024		December 31, 2023
Weighted-average remaining lease term (in years)	1.93		2.60
Weighted-average discount rate	6.75	%	6.75	%

Future minimum lease payments under operating lease liabilities were (in thousands):


	September 30, 2024
2024 (remaining three months)	$	735
2025	1,591
2026	1,195
Total future lease payments	3,521
Less: imputed interest	349
Total lease liability balance	3,172
Less: current portion of operating lease liabilities	1,761
Total operating lease liabilities, non-current	$	1,411

Company as Lessor: Tarzana Facility Lease with AstraZeneca


	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2024		2023		2024		2023
Rental income related to fixed lease income	$	1,493	$	—	$	1,493	$	—

Approximate future fixed contractual lease payments to be received under a non-cancelable operating lease in effect as of September 30, 2024, are as follows (in thousands):


	September 30, 2024
2024 (remaining three months)	$	1,493
2025	8,957
2026	8,957
2027	8,957
2028	8,957
Thereafter	94,795
Total	$	132,116

Legal Proceedings

Debt

The net carrying amount of the liability component of the Loan was as follows (in thousands):


	September 30, 2024		December 31, 2023
Principal amount	$	82,837	$	82,837
Unamortized debt issuance cost	(664)		(1,410)
Net carrying amount	$	82,173	$	81,427

The following table sets forth the interest expense recognized related to the Loan (in thousands):


	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2024		2023		2024		2023
Contractual interest expense	$	1,758	$	1,754	$	5,241	$	2,482
Amortization of debt issuance cost	249		249		747		747
Total interest expense related to the Loan	$	2,007	$	2,003	$	5,988	$	3,229

Other Commitments

Corporate Restructuring Plan - Schedule of Total Amount Expected to be Incurred and Liability (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Restructuring Cost and Reserve [Line Items]
Right-of-use asset impairment			$ 827	$ 7,724
Impairment of long-lived assets held for sale	$ 1,504	$ 4,572	4,285	16,233
Restructuring and impairment charges	2,362	46,283	7,146	71,847
Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0		1,400
Right-of-use asset impairment	640	128	827	7,724
Impairment of long-lived assets held for sale	1,500	4,600	4,300	16,200
Restructuring and impairment charges	2,362	46,283	7,146	71,847
Restructuring Plan \| One-time employee termination benefits
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1,449	41	2,427	1,816
Restructuring Plan \| Contract Terminations
Restructuring Cost and Reserve [Line Items]
Restructuring charges	(1,282)	0	(736)	1,888
Restructuring Plan \| Asset impairment for leasehold improvements
Restructuring Cost and Reserve [Line Items]
Asset Impairment Charges	51	0	343	2,644
Restructuring Plan \| Building and construction work in progress impairment
Restructuring Cost and Reserve [Line Items]
Asset Impairment Charges	$ 0	$ 41,542	$ 0	$ 41,542

Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2024

Share-Based Payment Arrangement [Abstract]

Schedule of Stock-Based Compensation Expense

The following table sets forth stock-based compensation included in the Company’s statement of operations and comprehensive loss (in thousands):


	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2024		2023		2024		2023
Research and development expense	$	506	$	567	$	1,587	$	999
General and administrative expense	3,562		4,103		11,169		12,614
Total stock-based compensation expense	$	4,068	$	4,670	$	12,756	$	13,613

License and Collaboration Agreement with ImmuneOnco (Details) - SynBioTx, Inc - USD ($) $ in Millions		3 Months Ended		9 Months Ended
	Aug. 01, 2024	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront payment	$ 10.0
Development costs		$ 5.0
Collaboration agreement costs incurred		$ 10.0	$ 0.0	$ 10.0	$ 0.0
Maximum \| License Agreement Terms
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Licensing agreement compensation	35.0
Maximum \| Commercial, development and regulatory milestones
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Licensing agreement compensation	2,100.0
Maximum \| Long-Term regulatory milestones
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Licensing agreement compensation	270.0
Maximum \| Commercial Milestones
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Licensing agreement compensation	$ 1,800.0

Commitments and Contingencies - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023	Jul. 10, 2024	Jun. 30, 2022
Lessee, Lease, Description [Line Items]
Impairment loss	$ 600,000	$ 100,000	$ 800,000	$ 7,200,000
Additional milestone payments, contingent amount			2,600,000
Milestone contingent amount payable			3,400,000
Complex Therapeutics LLC
Lessee, Lease, Description [Line Items]
Term of contract (in years)						15 years
Renewal term (in years)						5 years
Base rent, per month						$ 600,000
Base rent, per annually						$ 7,500,000
Rents increase in percentage						3.00%
Restructuring Plan
Lessee, Lease, Description [Line Items]
Restructuring charges	0		1,400,000
Contract Terminations \| Restructuring Plan
Lessee, Lease, Description [Line Items]
Restructuring charges	(1,282,000)	$ 0	(736,000)	$ 1,888,000
Non Cancelable Purchase Commitments with Contract Research Organizations \| Contract Terminations \| Restructuring Plan
Lessee, Lease, Description [Line Items]
Restructuring charges			2,000,000		$ 3,100,000
Secured Mortgage Loan
Lessee, Lease, Description [Line Items]
Repayments of debt					600,000
Secured Mortgage Loan \| Loans Payable
Lessee, Lease, Description [Line Items]
Initial principal amount	82,837,000		82,837,000		82,837,000		$ 52,100,000
Debt issuance costs	664,000		$ 664,000		1,410,000
Basis interest			5.25%
Covenant, minimum net worth	$ 85,000,000		$ 85,000,000		$ 85,000,000
Minimum
Lessee, Lease, Description [Line Items]
Original lease terms	2 years		2 years
Maximum
Lessee, Lease, Description [Line Items]
Original lease terms	5 years		5 years
Maximum \| Secured Mortgage Loan \| Loans Payable
Lessee, Lease, Description [Line Items]
Additional future principal (up to)							$ 32,900,000

Summary of Significant Accounting Policies

9 Months Ended

Sep. 30, 2024

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

Basis of Presentation

The accompanying condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and include the accounts of the Company and its wholly owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation.

The unaudited condensed consolidated financial statements have been prepared on the same basis as the audited annual consolidated financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair statement of the Company’s financial position as of September 30, 2024, the condensed consolidated statements of operations and comprehensive loss for the three and nine months ended September 30, 2024 and 2023, the condensed consolidated statements of stockholders’ equity for the three and nine months ended September 30, 2024 and 2023, and the results of its cash flows for the nine months ended September 30, 2024 and 2023. The financial data and other information disclosed in these notes related to the three and nine months ended September 30, 2024 and 2023 are also unaudited. The results for the three and nine months ended September 30, 2024 are not necessarily indicative of results to be expected for the year ending December 31, 2024, any other periods, or any future year period. The Company has evaluated subsequent events through the date the condensed consolidated financial statements were issued.

The accompanying unaudited condensed consolidated financial statements should be read in conjunction with the audited financial statements and the related notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023, as filed with the Securities and Exchange Commission (“SEC”) on March 21, 2024.

Reverse Stock Split

Effective December 7, 2023, the Company effected a 1-for-20 reverse stock split of its outstanding shares of common stock. Where applicable, all share and per share amounts in this Quarterly Report have been adjusted to reflect the effect of the reverse stock split.

Segments

Operating segments are identified as components of an entity for which separate discrete financial information is available and that is regularly reviewed by the chief operating decision-maker in deciding how to allocate resources to an individual segment and in assessing performance. The Company has determined it operates in a single operating segment and has one operating segment.

Cash, Cash Equivalents, Restricted Cash, Marketable Securities, and Long-Term Investments

The Company considers all highly liquid investments purchased with original maturities of three months or less from the purchase date to be cash equivalents. Cash equivalents include amounts invested in money market accounts.

Restricted cash consists of a cash reserve which serves as collateral for the Company’s construction loan and is classified within current assets on the condensed consolidated balance sheet as of September 30, 2024. There was no restricted cash as of September 30, 2024 and $1.5 million of restricted cash as of December 31, 2023 on the condensed consolidated balance sheet.

The Company’s investments in marketable securities and long-term investments have been classified and accounted for as available-for-sale. The Company classifies its maturities as either short-term or long-term based on each instrument’s underlying contractual maturity date, which are carried at their fair values based on the quoted market prices of the securities. Unrealized gains and losses are reported as accumulated other comprehensive income (loss). Realized gains and losses on available-for-sale securities are included in net loss in the period earned or incurred. As of September 30, 2024 and December 31, 2023, marketable securities consisted of U.S. Treasury bills.

The Company periodically reviews whether its securities may be other-than-temporarily impaired, including whether or not (i) the Company has the intent to sell the security or (ii) it is more likely than not that the Company will be required to sell the security before its anticipated recovery. If one of these factors is met, the Company will record an impairment loss associated with its impaired investment. The impairment loss will be recorded as a write-down of investments in the condensed consolidated balance sheets and a realized loss within other expense in the condensed consolidated statements of operations and comprehensive loss.


	September 30, 2024		December 31, 2023
Cash and cash equivalents	$	6,663	$	9,195
Restricted cash	—		1,501
Cash, cash equivalents and restricted cash	$	6,663	$	10,696

Assets Held for Sale

The Company classifies long-lived assets or disposal groups to be sold as held for sale in the period in which all of the following criteria are met: management, having the authority to approve the action, commits to a plan to sell the asset or disposal group; the asset or disposal group is available for immediate sale in its present condition subject only to terms that are usual and customary for sales of such assets or disposal group; the sale of the asset or disposal group is probable, and transfer of the asset or disposal group is expected to qualify for recognition as a completed sale within one year, except if events or circumstances beyond the Company’s control extend the period

of time required to sell the asset or disposal group beyond one year; the asset or disposal group is being actively marketed for sale at a price that is reasonable in relation to its current fair value; and actions required to complete the plan to sell have been initiated.

The Company initially measures a long-lived asset or disposal group that is held for sale at the lower of its carrying value or fair value less any costs to sell. Fair value is estimated by the Company through evaluations of quoted market prices received for other comparable held for sale assets sold by the Company. Any loss resulting from this measurement is recognized in the period in which the held for sale criteria are met. Conversely, gains are not recognized on the sale of a long-lived asset or disposal group until the date of sale. The Company assesses the fair value of a long-lived asset or disposal group less any costs to sell each reporting period it remains classified as held for sale and reports any subsequent changes as an adjustment to the carrying value of the asset or disposal group, as long as the new carrying value does not exceed the carrying value of the asset at the time it was initially classified as held for sale. Upon determining that a long-lived asset or disposal group meets the criteria to be classified as held for sale, the Company ceases depreciation and reports long-lived assets in the line item “assets held for sale” in its condensed consolidated balance sheet. To date, the Company has recorded impairment losses on assets held for sale associated with the Plan as defined below in Note 11. During the three and nine months ended September 30, 2024, the Company recognized non-cash impairment charges for assets held for sale of $1.5 million and $4.3 million, respectively, while during the three and nine months ended September 30, 2023 charges were $4.6 million and $16.2 million, respectively. The non-cash impairment charge was recorded in the condensed consolidated statements of operations and comprehensive loss in the line item “restructuring and impairment charges.”

Business Combinations

The Company evaluates acquisitions of assets and related liabilities and other similar transactions to assess whether or not the transaction should be accounted for as a business combination or asset acquisition by first applying a screen to determine if substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or group of similar identifiable assets. If the screen is met, the transaction is accounted for as an asset acquisition. If the screen is not met, further determination is required as to whether or not the Company has acquired inputs and processes that have the ability to create outputs which would meet the requirements of a business.

The Company accounts for its business combinations using the acquisition method of accounting which requires recognition and measurement of all identifiable assets acquired and liabilities assumed at their full fair value as of the date it obtains control. The Company has determined the fair value of assets acquired and liabilities assumed based upon management’s estimates of the fair values of assets acquired and liabilities assumed in the acquisitions. Goodwill represents the excess of the purchase price over the fair value of the net tangible and identifiable intangible assets acquired. The Company accounts for contingent consideration at the acquisition-date fair value as part of the consideration transferred in the transaction.

While management has used its best estimates and assumptions to measure the fair value of the identifiable assets acquired and liabilities assumed at the acquisition date, these estimates are inherently uncertain and subject to refinement. As a result, during the measurement period, not to exceed one year from the date of acquisition, any changes in the estimated fair values of the net assets recorded for the acquisitions will result in an adjustment to goodwill. Upon the conclusion of the measurement period or final determination of the values of assets acquired or liabilities assumed, whichever comes first, the Company records any subsequent adjustments to the consolidated statements of operations and comprehensive loss. Acquisition-related costs, such as legal and consulting fees, are expensed as incurred.

The Company accounts for an asset acquisition by recognizing net assets based on the cost to the acquiring entity on a relative fair value basis, which includes transaction costs in addition to consideration given. Goodwill is not recognized in an asset acquisition; any excess consideration transferred over the fair value of the net assets acquired is allocated to the non-monetary identifiable assets and liabilities assumed based on relative fair values. Acquired in-process research and development is expensed as incurred provided there is no alternative future use.

Impairment of Long-Lived Assets

The Company reviews its long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable or that the useful life is shorter than originally estimated. Recoverability of assets is measured by comparing the carrying amount of an asset to future undiscounted net cash flows expected to be generated by the asset over its remaining useful life. If such assets are impaired, the impairment recognized is measured by the amount by which the carrying amount of the assets exceeds the fair value of the assets. If the useful life is shorter than originally estimated, the Company depreciates or amortizes the remaining carrying value over the revised shorter useful life. Assets to be disposed of by sale are reflected at the lower of their carrying amount or fair value less costs to sell. To date, the Company has recorded impairment losses on long-lived assets associated with a sustained decrease in the Company’s stock price and in connection with the Plan as defined below in Note 11. The Company recognized a non-cash impairment charge of $0.1 million and $0.3 million during the three and nine months ended September 30, 2024, respectively, and nil and $2.6 million for the three and nine months ended September 30, 2023, respectively, related to leasehold improvements. Additionally, the Company recognized impairment charges of $41.5 million for the three and nine months ended September 30, 2023 relating to real estate. These impairment charges were recorded in the condensed consolidated statements of operations and comprehensive loss in the line item “restructuring and impairment charges.” See Notes 7 and 11 for more information.

Research and Development

Research and development costs are expensed as incurred. Clinical trial and other development costs incurred by third parties are expensed as the contracted work is performed. The Company accrues for costs incurred as the services are being provided by monitoring the status of the trial or project and the invoices received from its external service providers. The Company adjusts its accrual as actual costs become known. Where contingent milestone payments are due to third parties under research and development arrangements or license agreements, the milestone payment obligations are expensed when the milestone results are achieved.

Recent Accounting Pronouncements Not Yet Adopted

In November 2023, the FASB issued ASU No. 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures which requires public entities to disclose information about their reportable segments’ significant expenses on an interim and annual basis. ASU 2023-07 is effective for annual periods beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024, with early adoption permitted. The Company is currently evaluating the impact of this ASU 2023-07 on its consolidated financial statements and related disclosures.

In December 2023, the FASB issued ASU 2023-09 “Income Taxes (Topics 740): Improvements to Income Tax Disclosures” to expand the disclosure requirements for income taxes, specifically related to the rate reconciliation and income taxes paid. ASU 2023-09 is effective for annual periods beginning after December 15, 2024, with early adoption permitted. The Company is currently evaluating the impact of this ASU 2023-09 on its consolidated financial statements and related disclosures.

In November 2024, the FASB issued ASU no. 2024-03, Income Statement-Reporting Comprehensive Income-Expense Disaggregation Disclosures (Subtopic 220-40). The amendments in this update require disclosure, in the notes to the financial statements, of specific expense categories present within expense captions presented on the face of the income statement within continuing operations of public business entities. The amendments in this update are effective for annual periods beginning after December 15, 2026 and interim periods beginning after December 15, 2027.

A variety of proposed or otherwise potential accounting standards are currently being studied by standard-setting organizations and certain regulatory agencies. Because of the tentative and preliminary nature of such

proposed standards, the Company has not yet determined the effect, if any, that the implementation of such proposed standards would have on its condensed consolidated financial statements.

Commitments and Contingencies (Tables)

9 Months Ended

Sep. 30, 2024

Commitments and Contingencies Disclosure [Abstract]

Schedule of Lease Cost

The Company’s lease costs consist of the following (in thousands):


	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2024		2023		2024		2023
Operating lease cost	$	172	$	351	$	1,097	$	1,867
Variable lease cost	283		234		649		906
Total lease cost	$	455	$	585	$	1,746	$	2,773

The following table summarizes cash flow information related to the Company’s lease obligations (in thousands):


	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2024		2023		2024		2023
Cash paid for operating lease liabilities	$	494	$	491	$	1,756	$	1,806

The following table summarizes the Company’s lease assets and liabilities (in thousands):


	September 30, 2024		December 31, 2023
Operating lease right-of-use assets	$	1,104	$	2,387
Current operating lease liabilities	$	1,761	$	1,750
Non-current operating lease liabilities	$	1,411	$	2,877

The following table summarizes other supplemental information related to the Company’s lease obligations:


	September 30, 2024		December 31, 2023
Weighted-average remaining lease term (in years)	1.93		2.60
Weighted-average discount rate	6.75	%	6.75	%

Schedule of Future Minimum Lease Payments

Future minimum lease payments under operating lease liabilities were (in thousands):


	September 30, 2024
2024 (remaining three months)	$	735
2025	1,591
2026	1,195
Total future lease payments	3,521
Less: imputed interest	349
Total lease liability balance	3,172
Less: current portion of operating lease liabilities	1,761
Total operating lease liabilities, non-current	$	1,411

Schedule of Lease Income Related to the Operating Lease


	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2024		2023		2024		2023
Rental income related to fixed lease income	$	1,493	$	—	$	1,493	$	—

Schedule of Future Fixed Contractual Lease Payments to be Received

Approximate future fixed contractual lease payments to be received under a non-cancelable operating lease in effect as of September 30, 2024, are as follows (in thousands):


	September 30, 2024
2024 (remaining three months)	$	1,493
2025	8,957
2026	8,957
2027	8,957
2028	8,957
Thereafter	94,795
Total	$	132,116

Schedule of Net Carrying Amount of the Liability Component of the Loan

The net carrying amount of the liability component of the Loan was as follows (in thousands):


	September 30, 2024		December 31, 2023
Principal amount	$	82,837	$	82,837
Unamortized debt issuance cost	(664)		(1,410)
Net carrying amount	$	82,173	$	81,427

Schedule of Interest Expense Related to the Loan

The following table sets forth the interest expense recognized related to the Loan (in thousands):


	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2024		2023		2024		2023
Contractual interest expense	$	1,758	$	1,754	$	5,241	$	2,482
Amortization of debt issuance cost	249		249		747		747
Total interest expense related to the Loan	$	2,007	$	2,003	$	5,988	$	3,229

- Definition

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-SubTopic 10
-Topic 210
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 69B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481568/470-20-55-69B

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 69E
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481568/470-20-55-69E

Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-04(a))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-3

Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482925/835-30-45-2

Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-3

Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477734/942-470-50-3

Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
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-Section 50
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-8

Reference 9: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 505
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-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-6

Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-7

+ Details

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Sep. 30, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Summary of Significant Accounting Policies - Narrative (Details) $ in Thousands		3 Months Ended		9 Months Ended
	Dec. 07, 2023	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($) segment	Sep. 30, 2023 USD ($)	Dec. 31, 2023 USD ($)
Subsidiary or Equity Method Investee [Line Items]
Stock split	0.05
Number of segments \| segment				1
Restricted cash		$ 0		$ 0		$ 1,501
Impairment charges				4,285	$ 60,088
Impairment of long-lived assets held for sale		1,504	$ 4,572	4,285	16,233
Restructuring Plan
Subsidiary or Equity Method Investee [Line Items]
Impairment of long-lived assets held for sale		1,500	4,600	4,300	16,200
Leasehold improvements
Subsidiary or Equity Method Investee [Line Items]
Impairment charges		$ 100	0	$ 300	2,600
Land
Subsidiary or Equity Method Investee [Line Items]
Impairment charges			$ 41,500		$ 41,500

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive (Loss) Income	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2022		6,503,913
Beginning balance at Dec. 31, 2022	$ 363,605	$ 0	$ 788,992	$ (493)	$ (424,894)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	4,530		4,530
Net loss	(57,068)				(57,068)
Other comprehensive income (loss)	87			87
Ending balance (in shares) at Mar. 31, 2023		6,503,913
Ending balance at Mar. 31, 2023	311,154	$ 0	793,522	(406)	(481,962)
Beginning balance (in shares) at Dec. 31, 2022		6,503,913
Beginning balance at Dec. 31, 2022	363,605	$ 0	788,992	(493)	(424,894)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(143,162)
Ending balance (in shares) at Sep. 30, 2023		6,503,913
Ending balance at Sep. 30, 2023	234,024	$ 0	802,605	(525)	(568,056)
Beginning balance (in shares) at Mar. 31, 2023		6,503,913
Beginning balance at Mar. 31, 2023	311,154	$ 0	793,522	(406)	(481,962)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	4,413		4,413
Net loss	(18,662)				(18,662)
Other comprehensive income (loss)	(389)			(389)
Ending balance (in shares) at Jun. 30, 2023		6,503,913
Ending balance at Jun. 30, 2023	296,516	$ 0	797,935	(795)	(500,624)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	4,670		4,670
Net loss	(67,432)				(67,432)
Other comprehensive income (loss)	270			270
Ending balance (in shares) at Sep. 30, 2023		6,503,913
Ending balance at Sep. 30, 2023	$ 234,024	$ 0	802,605	(525)	(568,056)
Beginning balance (in shares) at Dec. 31, 2023	6,503,913	6,503,913
Beginning balance at Dec. 31, 2023	$ 225,829	$ 0	807,158	(348)	(580,981)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	4,515		4,515
Net loss	(24,302)				(24,302)
Other comprehensive income (loss)	(215)			(215)
Ending balance (in shares) at Mar. 31, 2024		6,503,913
Ending balance at Mar. 31, 2024	$ 205,827	$ 0	811,673	(563)	(605,283)
Beginning balance (in shares) at Dec. 31, 2023	6,503,913	6,503,913
Beginning balance at Dec. 31, 2023	$ 225,829	$ 0	807,158	(348)	(580,981)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ (62,240)
Ending balance (in shares) at Sep. 30, 2024	6,525,266	6,525,266
Ending balance at Sep. 30, 2024	$ 176,332	$ 0	820,073	(520)	(643,221)
Beginning balance (in shares) at Mar. 31, 2024		6,503,913
Beginning balance at Mar. 31, 2024	205,827	$ 0	811,673	(563)	(605,283)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	4,173		4,173
Net loss	(14,917)				(14,917)
Other comprehensive income (loss)	(64)			(64)
Ending balance (in shares) at Jun. 30, 2024		6,503,913
Ending balance at Jun. 30, 2024	195,019	$ 0	815,846	(627)	(620,200)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares of common stock issued in connection with incentive stock plan (in shares)		21,353
Shares of common stock issued in connection with incentive stock plan	159		159
Stock-based compensation	4,068		4,068
Net loss	(23,021)				(23,021)
Other comprehensive income (loss)	$ 107			107
Ending balance (in shares) at Sep. 30, 2024	6,525,266	6,525,266
Ending balance at Sep. 30, 2024	$ 176,332	$ 0	$ 820,073	$ (520)	$ (643,221)

- Definition

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

+ References

+ Details

- Definition

Amount of equity (deficit) attributable to parent. Excludes temporary equity and equity attributable to noncontrolling interest.

+ References

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+ Details

Fair Value Measurement

9 Months Ended

Sep. 30, 2024

Fair Value Disclosures [Abstract]

Fair Value Measurement

The fair value of cash and cash equivalents approximates carrying value since cash and cash equivalents consist of short-term highly liquid investments with maturities of less than three months at the time of purchase. Cash and cash equivalents are quoted market prices in active markets for identical assets and are therefore classified as Level 1 assets. Money market funds are open-end mutual funds that invest in cash, government securities, and/or repurchase agreements that are collateralized fully. To the extent that these funds are valued based upon the reported net asset value, they are categorized in Level 1 of the fair value hierarchy.

Short-term and long-term marketable securities comprised U.S. Treasury bills that are classified within Level 2 of the fair value hierarchy are valued based on other observable inputs, including broker or dealer quotations, alternative pricing sources or U.S. Government Treasury yield of appropriate term.

The following tables provide information by level for assets and liabilities that are measured at fair value on a recurring and nonrecurring basis:


	September 30, 2024
	Level 1		Level 2		Level 3		Total
	(In thousands)
Financial Assets
Money market funds	$	3,275	$	—	$	—	$	3,275
U.S. Treasury bills	—		116,247		—		116,247
Derivative financial instrument	—		790		—		790
Total	$	3,275	$	117,037	$	—	$	120,312
Financial Liabilities
Contingent consideration	$	—	$	—	$	2,358	$	2,358

	December 31, 2023
	Level 1		Level 2		Level 3		Total
	(In thousands)
Financial Assets
Money market funds	$	5,684	$	—	$	—	$	5,684
U.S. Treasury bills	—		164,322		—		164,322
Derivative financial instrument	—		1,055		—		1,055
Total	$	5,684	$	165,377	$	—	$	171,061
Financial Liabilities
Contingent consideration	$	—	$	—	$	4,858	$	4,858

There were no transfers in or out of Level 1, 2 and 3 measurements for the nine months ended September 30, 2024 and the year ended December 31, 2023. As of September 30, 2024 and December 31, 2023, there were no securities within Level 3 of the fair value hierarchy. The derivative financial instrument above relates to the interest rate swap discussed in Note 7, and is included in prepaid expenses and current assets in the condensed consolidated balance sheets.

As of September 30, 2024, the fair value of the Company’s Loan (as defined in Note 7) was $77.7 million. The fair value was determined on the basis of its net present value and is considered Level 2 in the fair value hierarchy.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References

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+ Details

Corporate Restructuring Plan

9 Months Ended

Sep. 30, 2024

Restructuring and Related Activities [Abstract]

Corporate Restructuring Plan

In December 2022, the Board of Directors approved a strategic reprioritization of the Company’s preclinical and clinical development programs (referred to as the “2022 Plan”). In January 2023, the Board approved an additional restructuring plan (referred to as the “2023 Plan”) and the Company announced the consolidation of the ITIL-306 Phase 1 clinical trial and related manufacturing of CoStAR-TIL to its operations in Manchester, UK and stopped recruiting for the ITIL-306 clinical trial.

In January 2024, the Board of Directors approved a comprehensive restructuring plan, which included the closure of the Company’s UK manufacturing facility and clinical trial operations, as well as the cessation of the ITIL-306 clinical trial. In September 2024, the Board of Directors approved additional UK restructuring actions, which has resulted in the elimination of the majority of the remaining UK workforce, with the remaining reduction and restructuring activities anticipated to be largely completed by the end of 2024. Collectively, these actions are referred to as the “2024 Plan.”

The 2022 Plan, 2023 Plan and 2024 Plan are collectively referred to as the “Plan”.

Restructuring and Impairment Charges

As a result of the Plan, the Company recorded charges of $2.4 million and $7.1 million within the condensed consolidated statements of operations and comprehensive loss in the line item “restructuring and impairment charges” for the three and nine months ended September 30, 2024, respectively, and $46.3 million and $71.8 million for the three and nine months ended September 30, 2023, respectively.

The Company estimates that it will incur additional charges of up to $0.5 million by the end of 2024, including employee termination costs, severance and other benefits, and contract termination costs. The charges that the Company expects to incur in connection with the 2024 Plan are subject to a number of assumptions, and actual results may differ materially.

These charges relate to asset impairments, contract terminations, severance payments and other employee-related costs incurred. The following table summarizes the restructuring and impairment charges by category (in thousands):


	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2024		2023		2024		2023
Asset impairment for leasehold improvements	$	51	$	—	$	343	$	2,644
One-time employee termination benefits	1,449		41		2,427		1,816
Building and construction work in progress impairment	—		41,542		—		41,542
Contract terminations	(1,282)		—		(736)		1,888
Right-of-use asset impairment	640		128		827		7,724
Impairment of long-lived assets held for sale	1,504		4,572		4,285		16,233
Total restructuring and impairment charges	$	2,362	$	46,283	$	7,146	$	71,847

Restructuring Liability

As a result of the Plan, the restructuring liability was recorded in the condensed consolidated balance sheets under “Accrued expenses and other current liabilities” and was measured at the amount expected to be paid, or that was paid. During the three and nine months ended September 30, 2024, the Company paid nil and $1.4 million of restructuring costs, respectively, and expects to pay the remainder of the restructuring costs by the end of 2024. The following table shows the liability related to the Plan (in thousands):


	Employee Benefits		Contract Terminations		Total
Restructuring liability as of December 31, 2023	$	—	$	3,136	$	3,136
Additions, net	2,395		720		3,115
Payments	(978)		(471)		(1,449)
Adjustments	—		(1,349)		(1,349)
Total restructuring liability as of September 30, 2024	$	1,417	$	2,036	$	3,453

Financial Instruments

9 Months Ended

Sep. 30, 2024

Investments, Debt and Equity Securities [Abstract]

Financial Instruments

Marketable securities and long-term investments classified as available-for-sale on September 30, 2024 and December 31, 2023 consisted of the following (in thousands):


	September 30, 2024
	Maturity	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
U.S. Treasury bills	Less than one year	$	113,496	$	194	$	—	$	113,690
U.S. Treasury bills	Between one and two years	2,559		—		(2)		2,557
Total		$	116,055	$	194	$	(2)	$	116,247


	December 31, 2023
	Maturity	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
U.S. Treasury bills	Less than one year	$	141,075	$	86	$	—	$	141,161
U.S. Treasury bills	Between one and two years	23,134		27		—		23,161
Total		$	164,209	$	113	$	—	$	164,322

As of September 30, 2024 and December 31, 2023, marketable securities that had contractual maturities less than one year are classified as current because management considers these marketable securities to be available for current operations. As of September 30, 2024 and December 31, 2023, marketable securities that had contractual maturities between one and two years are classified as long-term because management considers these marketable securities to be available for operations beyond one year. The Company does not intend to sell its marketable securities and it is not likely that the Company will be required to sell these securities before recovery of their amortized cost basis. There were $113.7 million of marketable securities and $2.6 million of long-term investments maturing in less than two years classified as available-for-sale as of September 30, 2024. There were $141.2 million of marketable securities and $23.2 million of long-term investments maturing in less than two years classified as available-for-sale as of December 31, 2023.