0001558370-24-012231 | 10-Q | XBRL Viewer

Basis of Presentation	6 Months Ended
Jun. 30, 2024
Business.
Basis of Presentation	2. Basis of Presentation The Company’s condensed consolidated financial statements include the results of the financial operations of Cara Therapeutics, Inc. and its wholly-owned subsidiary, Cara Royalty Sub, LLC, or Cara Royalty Sub, a Delaware limited liability company which was formed in November 2023 for the purpose of the transactions contemplated by the HCR Agreement described in Note 10, Royalty Purchase and Sale Agreement. All intercompany balances and transactions have been eliminated. The unaudited interim condensed consolidated financial statements included herein have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission, or SEC. Accordingly, they do not include all information and disclosures necessary for a presentation of the Company’s financial position, results of operations and cash flows in conformity with generally accepted accounting principles in the United States of America, or GAAP. In the opinion of management, these unaudited interim condensed consolidated financial statements reflect all adjustments, consisting primarily of normal recurring accruals, necessary for a fair presentation of results for the periods presented. The results of operations for interim periods are not necessarily indicative of the results for the full year. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted from this report, as is permitted by SEC rules and regulations; however, the Company believes that the disclosures are adequate to make the information presented not misleading. The condensed consolidated balance sheet data as of December 31, 2023 were derived from audited financial statements, but do not include all disclosures required by GAAP. These unaudited interim condensed consolidated financial statements should be read in conjunction with the audited financial statements and accompanying notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023. Use of Estimates The preparation of condensed consolidated financial statements in conformity with GAAP requires the Company to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities, as of the date of the condensed consolidated financial statements as well as the reported amounts of revenues and expenses during the reporting period. The more significant estimates include the fair value of marketable securities that are classified as Level 2 of the fair value hierarchy, the amount and periods over which certain revenues will be recognized, including licensing and collaborative revenue recognized from non-refundable up-front and milestone payments and future ex-U.S. royalties and milestones projected in relation to the HCR Agreement, related party accounts receivable reserve, as applicable, inventory valuation and related reserves, research and development, or R&D, clinical costs and accrued research projects included in prepaid expenses and accounts payable and accrued expenses, the amount of non-cash compensation costs related to share-based payments to employees and non-employees, restructuring costs, the amount of lease incentives, as applicable, and the incremental borrowing rate used in lease calculations, and the likelihood of realization of deferred tax assets. The impact from global economic conditions and potential and continuing disruptions to and volatility in the credit and equity markets in the United States and worldwide are highly uncertain and cannot be predicted, including impacts from global health crises, geopolitical tensions, such as the ongoing conflicts between Russia and Ukraine, conflict in the Middle East, and increasing tensions between China and Taiwan, and government actions implemented as a result of the foregoing, fluctuations in inflation, rising interest rates, uncertainty and liquidity concerns in the broader financial services industry, and a potential recession in the United States. Estimates and assumptions about future events and their effects cannot be determined with certainty and therefore require the exercise of judgment. As of the date of issuance of these condensed consolidated financial statements, the Company is not aware of any specific event or circumstance that would require the Company to update its estimates, assumptions and judgments or revise the reported amounts of assets and liabilities or the disclosure of contingent assets and liabilities. These estimates, however, may change as new events occur and additional information is obtained, and are recognized in the condensed consolidated financial statements as soon as they become known. Actual results could differ materially from the Company’s estimates and assumptions. Significant Accounting Policies There have been no material changes to the significant accounting policies previously disclosed in Note 2 to the Consolidated Financial Statements in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023. Accounting Pronouncements Recently Adopted In November 2023, the Financial Accounting Standards Board, or FASB, issued Accounting Standards Update, or ASU, 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, or ASU 2023-07, which expanded the disclosures for reportable segments made by public entities. These amendments within ASU 2023-07 retained the existing disclosure requirements in ASC 280 and expanded upon them to require public entities to disclose significant expenses for reportable segments in both interim and annual reporting periods, as well as items that were previously disclosed only annually on an interim basis, including disclosures related to a reportable segment’s profit or loss and assets. In addition, entities with a single reportable segment must provide all segment disclosures required in ASC 280, including the new disclosures for reportable segments under the amendments in ASU 2023-07. The amendments did not change the existing guidance on how a public entity identified and determined its reportable segments. A public entity should apply the amendments in ASU 2023-07 retrospectively to all prior periods presented in the financial statements. Upon transition, the segment expense categories and amounts disclosed in the prior periods should be based on the significant segment expense categories identified and disclosed in the period of adoption. The amendments in ASU 2023-07 are effective for annual periods for all public entities in fiscal years beginning after December 15, 2023, and in interim periods within fiscal years beginning after December 15, 2024. The Company adopted ASU 2023-07 on January 1, 2024, and expects to comply with any new applicable disclosures in its Annual Report on Form 10-K for the year ended December 31, 2024. The Company does not expect the adoption to have a material effect on its results of operations, financial position, and cash flows. Accounting Pronouncements Not Yet Adopted In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, or ASU 2023-09, which applies to all entities subject to income taxes. ASU 2023-09 requires disaggregated information about a reporting entity’s effective tax rate reconciliation as well as information on income taxes paid. ASU 2023-09 is intended to provide more detailed income tax disclosures. For public business entities (PBEs), the new requirements will be effective for annual periods beginning after December 15, 2024. ASU 2023-09 will be applied on a prospective basis with the option to apply the standard retrospectively. The Company expects to adopt ASU 2023-09 on January 1, 2025, and it does not expect the adoption to have a material effect on its results of operations, financial position, and cash flows.

Basis of Presentation

6 Months Ended

Jun. 30, 2024

2. Basis of Presentation

The Company’s condensed consolidated financial statements include the results of the financial operations of Cara Therapeutics, Inc. and its wholly-owned subsidiary, Cara Royalty Sub, LLC, or Cara Royalty Sub, a Delaware limited liability company which was formed in November 2023 for the purpose of the transactions contemplated by the HCR Agreement described in Note 10, Royalty Purchase and Sale Agreement. All intercompany balances and transactions have been eliminated.

The unaudited interim condensed consolidated financial statements included herein have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission, or SEC. Accordingly, they do not include all information and disclosures necessary for a presentation of the Company’s financial position, results of operations and cash flows in conformity with generally accepted accounting principles in the United States of America, or GAAP. In the opinion of management, these unaudited interim condensed consolidated financial statements reflect all adjustments, consisting primarily of normal recurring accruals, necessary for a fair presentation of results for the periods presented. The results of operations for interim periods are not necessarily indicative of the results for the full year. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted from this report, as is permitted by SEC rules and regulations; however, the Company believes that the disclosures are adequate to make the information presented not misleading. The condensed consolidated balance sheet data as of December 31, 2023 were derived from audited financial statements, but do not include all disclosures required by GAAP. These unaudited interim condensed consolidated financial statements should be read in conjunction with the audited financial statements and accompanying notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023.

Use of Estimates

The preparation of condensed consolidated financial statements in conformity with GAAP requires the Company to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities, as of the date of the condensed consolidated financial statements as well as the reported amounts of revenues and expenses during the reporting period. The more significant estimates include the fair value of marketable securities that are classified as Level 2 of the fair value hierarchy, the amount and periods over which certain revenues will be recognized, including licensing and collaborative revenue recognized from non-refundable up-front and milestone payments and future ex-U.S. royalties and milestones projected in relation to the HCR Agreement, related party accounts receivable reserve, as applicable, inventory valuation and related reserves, research and development, or R&D, clinical costs and accrued research projects included in prepaid expenses and accounts payable and accrued expenses, the amount of non-cash compensation costs related to share-based payments to employees and non-employees, restructuring costs, the amount of lease incentives, as applicable, and the incremental borrowing rate used in lease calculations, and the likelihood of realization of deferred tax assets.

The impact from global economic conditions and potential and continuing disruptions to and volatility in the credit and equity markets in the United States and worldwide are highly uncertain and cannot be predicted, including impacts from global health crises, geopolitical tensions, such as the ongoing conflicts between Russia and Ukraine, conflict in the Middle East, and increasing tensions between China and Taiwan, and government actions implemented as a result of the foregoing, fluctuations in inflation, rising interest rates, uncertainty and liquidity concerns in the broader financial services industry, and a potential recession in the United States. Estimates and assumptions about future events and their effects cannot be determined with certainty and therefore require the exercise of judgment. As of the date of issuance of

these condensed consolidated financial statements, the Company is not aware of any specific event or circumstance that would require the Company to update its estimates, assumptions and judgments or revise the reported amounts of assets and liabilities or the disclosure of contingent assets and liabilities. These estimates, however, may change as new events occur and additional information is obtained, and are recognized in the condensed consolidated financial statements as soon as they become known.

Actual results could differ materially from the Company’s estimates and assumptions.

Significant Accounting Policies

There have been no material changes to the significant accounting policies previously disclosed in Note 2 to the Consolidated Financial Statements in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023.

Accounting Pronouncements Recently Adopted

In November 2023, the Financial Accounting Standards Board, or FASB, issued Accounting Standards Update, or ASU, 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, or ASU 2023-07, which expanded the disclosures for reportable segments made by public entities. These amendments within ASU 2023-07 retained the existing disclosure requirements in ASC 280 and expanded upon them to require public entities to disclose significant expenses for reportable segments in both interim and annual reporting periods, as well as items that were previously disclosed only annually on an interim basis, including disclosures related to a reportable segment’s profit or loss and assets. In addition, entities with a single reportable segment must provide all segment disclosures required in ASC 280, including the new disclosures for reportable segments under the amendments in ASU 2023-07. The amendments did not change the existing guidance on how a public entity identified and determined its reportable segments. A public entity should apply the amendments in ASU 2023-07 retrospectively to all prior periods presented in the financial statements. Upon transition, the segment expense categories and amounts disclosed in the prior periods should be based on the significant segment expense categories identified and disclosed in the period of adoption. The amendments in ASU 2023-07 are effective for annual periods for all public entities in fiscal years beginning after December 15, 2023, and in interim periods within fiscal years beginning after December 15, 2024. The Company adopted ASU 2023-07 on January 1, 2024, and expects to comply with any new applicable disclosures in its Annual Report on Form 10-K for the year ended December 31, 2024. The Company does not expect the adoption to have a material effect on its results of operations, financial position, and cash flows.

Accounting Pronouncements Not Yet Adopted

In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, or ASU 2023-09, which applies to all entities subject to income taxes. ASU 2023-09 requires disaggregated information about a reporting entity’s effective tax rate reconciliation as well as information on income taxes paid. ASU 2023-09 is intended to provide more detailed income tax disclosures. For public business entities (PBEs), the new requirements will be effective for annual periods beginning after December 15, 2024. ASU 2023-09 will be applied on a prospective basis with the option to apply the standard retrospectively. The Company expects to adopt ASU 2023-09 on January 1, 2025, and it does not expect the adoption to have a material effect on its results of operations, financial position, and cash flows.

Stockholders' Equity	6 Months Ended
Jun. 30, 2024
Stockholders' Equity
Stockholders' Equity	11. Stockholders’ Equity On June 7, 2024, the Company filed a Certificate of Amendment to its Certificate of Incorporation, or the Certificate, with the Secretary of State of the State of Delaware, which the Company’s stockholders approved at the Company’s Annual Meeting of Stockholders on June 4, 2024. The Certificate increased the authorized number of shares of common stock of the Company from 100,000,000 shares to 200,000,000 shares. The additional shares of common stock authorized by the Certificate have rights identical to the currently outstanding common stock of the Company and any issuance of common stock authorized by the Certificate would not affect the rights of the holders of currently outstanding common stock of the Company, except for effects incidental to increasing the number of shares of the Company’s common stock outstanding, such as dilution of the earnings per share and voting rights of current holders of common stock. As of June 30, 2024, there were 54,837,764 shares of common stock and no shares of preferred stock issued and outstanding. Each share of common stock entitles the holder to one vote on all matters submitted to a vote of the Company’s stockholders. Common stockholders are entitled to dividends when and if declared by the Board of Directors, subject to the preferential rights of the holders of preferred stock, if any. During the three months ended June 30, 2024, an aggregate of 170,685 time-based restricted stock units of certain employees and the Board of Directors vested and were settled in shares of the Company’s common stock. During the six months ended June 30, 2024, an aggregate of 216,560 time-based restricted stock units of certain employees and the Board of Directors vested and were settled in shares of the Company’s common stock (See Note 15, Stock-Based Compensation). During the three months ended June 30, 2024, no performance-based restricted stock units vested or were settled in shares of the Company’s common stock. During the six months ended June 30, 2024, an aggregate of 140,500 performance-based restricted stock units of certain employees vested and were settled in shares of the Company’s common stock (See Note 15, Stock-Based Compensation). During the three months ended June 30, 2023, an aggregate of 94,454 time-based restricted stock units of certain employees and the Board of Directors vested and were settled in shares of the Company’s common stock. During the six months ended June 30, 2023, an aggregate of 178,247 time-based restricted stock units of certain employees and the Board of Directors were settled in shares of the Company’s common stock (see Note 15, Stock-Based Compensation). During the three and six months ended June 30, 2023, no performance-based restricted stock units vested or were settled in shares of the Company’s common stock.

Stockholders' Equity

6 Months Ended

Jun. 30, 2024

Stockholders' Equity

Stockholders' Equity

11. Stockholders’ Equity

On June 7, 2024, the Company filed a Certificate of Amendment to its Certificate of Incorporation, or the Certificate, with the Secretary of State of the State of Delaware, which the Company’s stockholders approved at the Company’s Annual Meeting of Stockholders on June 4, 2024. The Certificate increased the authorized number of shares of common stock of the Company from 100,000,000 shares to 200,000,000 shares. The additional shares of common stock authorized by the Certificate have rights identical to the currently outstanding common stock of the Company and any issuance of common stock authorized by the Certificate would not affect the rights of the holders of currently

outstanding common stock of the Company, except for effects incidental to increasing the number of shares of the Company’s common stock outstanding, such as dilution of the earnings per share and voting rights of current holders of common stock. As of June 30, 2024, there were 54,837,764 shares of common stock and no shares of preferred stock issued and outstanding.

Each share of common stock entitles the holder to one vote on all matters submitted to a vote of the Company’s stockholders. Common stockholders are entitled to dividends when and if declared by the Board of Directors, subject to the preferential rights of the holders of preferred stock, if any.

During the three months ended June 30, 2024, an aggregate of 170,685 time-based restricted stock units of certain employees and the Board of Directors vested and were settled in shares of the Company’s common stock. During the six months ended June 30, 2024, an aggregate of 216,560 time-based restricted stock units of certain employees and the Board of Directors vested and were settled in shares of the Company’s common stock (See Note 15, Stock-Based Compensation).

During the three months ended June 30, 2024, no performance-based restricted stock units vested or were settled in shares of the Company’s common stock. During the six months ended June 30, 2024, an aggregate of 140,500 performance-based restricted stock units of certain employees vested and were settled in shares of the Company’s common stock (See Note 15, Stock-Based Compensation).

During the three months ended June 30, 2023, an aggregate of 94,454 time-based restricted stock units of certain employees and the Board of Directors vested and were settled in shares of the Company’s common stock. During the six months ended June 30, 2023, an aggregate of 178,247 time-based restricted stock units of certain employees and the Board of Directors were settled in shares of the Company’s common stock (see Note 15, Stock-Based Compensation).

During the three and six months ended June 30, 2023, no performance-based restricted stock units vested or were settled in shares of the Company’s common stock.

- Definition

The entire disclosure for equity.

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+ Details

Revenue Recognition - Disaggregation of Revenue (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Disaggregation of Revenue [Line Items]
Total revenue	$ 991	$ 6,933	$ 3,126	$ 13,098
Other revenue (non-cash)
Disaggregation of Revenue [Line Items]
Total revenue	991	0	1,614	0
Other revenue (non-cash) \| Maruishi Agreement [Member]
Disaggregation of Revenue [Line Items]
Total revenue	632		965
Other revenue (non-cash) \| Affiliated Entity [Member] \| CSL Vifor \| CSL Vifor Kapruvia [Member]
Disaggregation of Revenue [Line Items]
Total revenue	359		649
Collaborative revenue
Disaggregation of Revenue [Line Items]
Total revenue		5,410	788	8,160
Collaborative revenue \| Affiliated Entity [Member] \| CSL Vifor \| CSL Vifor Profit Sharing
Disaggregation of Revenue [Line Items]
Total revenue		5,410	788	8,160
Commercial supply revenue
Disaggregation of Revenue [Line Items]
Total revenue		1,400	640	4,591
Commercial supply revenue \| Affiliated Entity [Member] \| CSL Vifor \| CSL Vifor Korsuva [Member]
Disaggregation of Revenue [Line Items]
Total revenue	0	1,400	640	4,591
Clinical compound revenue
Disaggregation of Revenue [Line Items]
Total revenue			84	99
Clinical compound revenue \| Maruishi Agreement [Member]
Disaggregation of Revenue [Line Items]
Total revenue	0	0	84	99
Royalty revenue
Disaggregation of Revenue [Line Items]
Total revenue		123		248
Royalty revenue \| Affiliated Entity [Member] \| CSL Vifor \| CSL Vifor Kapruvia [Member]
Disaggregation of Revenue [Line Items]
Total revenue	$ 0	$ 123	$ 0	$ 248

Available-for-Sale Marketable Securities - Summary of Available-for-Sale Marketable Securities by Major Type of Security (Detail) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	$ 7,500	$ 49,243
Gross Unrealized Gains		3
Gross Unrealized Losses	(121)	(263)
Estimated fair value	7,379	48,983
U.S. Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost		37,243
Gross Unrealized Gains		3
Estimated fair value		37,246
U.S. Government Agency Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	7,500	7,500
Gross Unrealized Losses	(121)	(262)
Estimated fair value	$ 7,379	7,238
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost		4,500
Gross Unrealized Losses		(1)
Estimated fair value		$ 4,499

- 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.

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CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 49,239	$ 51,775
Marketable securities	7,379	48,983
Accounts receivable, net - related party	359	2,765
Inventory, net	1,644	2,821
Income tax receivable	697	697
Other receivables	764	555
Prepaid expenses	3,777	8,154
Restricted cash		408
Total current assets	63,859	116,158
Operating lease right-of-use assets	3,646	4,864
Property and equipment, net	3,490	3,322
Restricted cash, non-current	1,500	1,500
Total assets	72,495	125,844
Current liabilities:
Accounts payable and accrued expenses	13,733	25,592
Operating lease liability, current	168
Total current liabilities	13,901	25,592
Liability related to sales of future royalties and milestones, net	39,676	37,079
Operating lease liability, non-current	7,320	6,088
Total liabilities	60,897	68,759
Commitments and contingencies (Note 17)
Stockholders' equity:
Preferred stock; $0.001 par value; 5,000,000 shares authorized at June 30, 2024 and December 31, 2023, zero shares issued and outstanding at June 30, 2024 and December 31, 2023
Common stock; $0.001 par value; 200,000,000 shares and 100,000,000 shares authorized at June 30, 2024 and December 31, 2023, respectively, 54,837,764 shares and 54,480,704 shares issued and outstanding at June 30, 2024 and December 31, 2023, respectively	54	54
Additional paid-in capital	747,122	742,036
Accumulated deficit	(735,457)	(684,745)
Accumulated other comprehensive loss	(121)	(260)
Total stockholders' equity	11,598	57,085
Total liabilities and stockholders' equity	$ 72,495	$ 125,844

Commitments and Contingencies - Schedule of Future Minimum Lease Payments under Non-cancellable Operating Leases, Reconciliation of Undiscounted Cash Flows to the Operating Lease Liability (Detail) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Operating Lease Liabilities, Payments Due [Abstract]
2024 (Excluding the six months ended June 30, 2024)	$ 108
2025	1,298
2026	1,330
2027	1,363
2028	1,398
Thereafter	8,874
Total future minimum lease payments, undiscounted	14,371
Less imputed interest	(6,883)
Total	7,488
Operating lease liability reported as of June 30, 2024:
Operating lease liability - current	168
Operating lease liability - non-current	7,320	$ 6,088
Total	$ 7,488

Net Loss per Share - Computation of Basic and Diluted Net Loss per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2024	Jun. 30, 2023
Net Loss Per Share
Net loss - basic and diluted	$ (20,016)	$ (30,696)	$ (31,479)	$ (26,665)	$ (50,712)	$ (58,144)
Weighted-average common shares outstanding:
Basic	54,724,692		54,002,988		54,656,391	53,937,875
Diluted	54,724,692		54,002,988		54,656,391	53,937,875
Net loss per share:
Basic	$ (0.37)		$ (0.58)		$ (0.93)	$ (1.08)
Diluted	$ (0.37)		$ (0.58)		$ (0.93)	$ (1.08)

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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-URI https://asc.fasb.org//1943274/2147482740/230-10-45-28

Reference 36: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1A
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482790/220-10-45-1A

Reference 37: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1B
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482790/220-10-45-1B

Reference 38: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(20))
-Publisher FASB
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Reference 39: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(22))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483589/942-220-S99-1

+ Details

Revenue Recognition

6 Months Ended

Jun. 30, 2024

Revenue Recognition

Revenue Recognition

13. Revenue Recognition

The Company has recognized revenue under its license and collaboration agreements from (1) its share of the profit generated by KORSUVA injection sales in the United States during the six months ended June 30, 2024 and the three and six months ended June 30, 2023; (2) commercial supply revenue from the Company’s sales of commercial product

to CSL Vifor during the six months ended June 30, 2024 and the three and six months ended June 30, 2023; (3) royalty revenue from net sales of Kapruvia in Europe during each of the three and six months ended June 30, 2023; (4) clinical compound sales from certain license agreements during each of the six months ended June 30, 2024 and 2023; and (5) other revenue which represents royalty payments earned by the Company under Vifor Agreement No. 2 and the Maruishi Agreement under the HCR Agreement during the three and six months ended June 30, 2024. As of June 30, 2024, the Company has not earned any sales-based milestones under its collaboration agreements.

As of June 30, 2024, the Company had license and collaboration agreements with CSL Vifor, Maruishi and CKDP. The following table provides amounts included in the Company’s Condensed Consolidated Statements of Comprehensive Loss as revenue for each of the three and six months ended June 30, 2024 and 2023, respectively:


	Three Months Ended June 30,				Six Months Ended June 30,
	2024		2023			2024	2023
Collaborative revenue
CSL Vifor (KORSUVA injection profit sharing)	$	—	$	5,410	$	788	$	8,160
Total collaborative revenue	$	—	$	5,410	$	788	$	8,160
Commercial supply revenue
CSL Vifor (KORSUVA injection)	$	—	$	1,400	$	640	$	4,591
Total commercial supply revenue	$	—	$	1,400	$	640	$	4,591
Royalty revenue
CSL Vifor (Kapruvia ex-U.S.)	$	—	$	123	$	—	$	248
Total royalty revenue	$	—	$	123	$	—	$	248
Clinical compound revenue
Maruishi	$	—	$	—	$	84	$	99
Total clinical compound revenue	$	—	$	—	$	84	$	99
Other revenue (non-cash)
CSL Vifor (Kapruvia ex-U.S.)	$	359	$	—	$	649	$	—
Maruishi		632		—		965		—
Total other revenue	$	991	$	—	$	1,614	$	—

Collaborative revenue

Beginning in April 2022, the Company began recording its share of the profit generated by KORSUVA injection sales by CSL Vifor to third parties in the United States. Under the license agreements with CSL Vifor, KORSUVA injection net sales are calculated by CSL Vifor which are net of discounts, rebates, and allowances. These amounts include the use of estimates and judgments, which could be adjusted based on actual results in the future. The Company records its share of the net profits from the sales of KORSUVA injection in the United States on a net basis (since the Company is not the primary obligor and does not retain inventory risk) and presents the revenue earned each period as collaborative revenue.

For the three months ended June 30, 2024, CSL Vifor recorded net sales of KORSUVA injection in the United States of approximately negative $2,664, which resulted in the Company’s profit share amount of negative $1,447. For the three months ended June 30, 2023, CSL Vifor recorded net sales of $11,467, which resulted in the Company’s profit share amount of $5,410. The negative net sales reported by CSL Vifor was primarily due to higher rebates and chargebacks due to price decreases on KORSUVA injection related to the expiration of Transition Drug Add-on Payment Adjustment in April 2024. Based on the terms of the agreement, the negative profit will be offset against net

profits in future periods. However, the Company has recorded a liability in accrued professional fees and other within accounts payable and accrued expenses for $1,447 and a corresponding expense in other general and administrative, or G&A, expense as a result of the negative profit share amount in the second quarter of 2024. For the six months ended June 30, 2024, CSL Vifor recorded net sales of KORSUVA injection in the United States of approximately negative $858. For the six months ended June 30, 2023, CSL Vifor recorded net sales of KORSUVA injection in the United States of approximately $17,141. For the six months ended June 30, 2024 and 2023, the Company recorded associated collaborative revenue of $788 and $8,160, respectively.

Commercial supply revenue

Under the Vifor International Supply Agreement, the Company’s only performance obligation is the delivery of KORSUVA injection to CSL Vifor in accordance with the receipt of purchase orders. Revenue from the sale of commercial supply product to CSL Vifor is recognized as delivery of the product occurs. There was no commercial supply revenue for the three months ended June 30, 2024. The Company had commercial supply revenue of $1,400 for the three months ended June 30, 2023, with associated COGS of $1,418, and $640 and $4,591 for the six months ended June 30, 2024 and 2023, respectively, with associated COGS of $620 and $4,008, respectively.

Royalty revenue

Royalty revenue includes amounts related to the Company’s royalties earned from CSL Vifor on the net sales of Kapruvia in Europe, based on the amount of net sales in a licensed territory during a calendar year. Sales-based royalty payments related to a license of IP are recognized as revenue when the respective sales occur, and the net sales tier is achieved. The Company recognized royalty revenue of approximately $123 and $248 for the three and six months ended June 30, 2023, respectively, which were related to the Company’s royalties on the net sales of Kapruvia in Europe. Beginning on October 1, 2023, royalty revenue is no longer recognized until the Company has fulfilled its obligations under the HCR Agreement (see Note 10, Royalty Purchase and Sale Agreement).

Clinical compound revenue

The Company’s only performance obligation under the supply agreement with Maruishi is to deliver clinical compound to Maruishi in accordance with the receipt of purchase orders. There was no clinical compound revenue for the three months ended June 30, 2024 and 2023. During the six months ended June 30, 2024 and 2023, the Company recognized clinical compound revenue of $84 and $99, respectively, from the sale of clinical compound to Maruishi.

Other revenue

The Company recorded other non-cash revenue of $991 and $1,614 which represents the royalty payments earned by the Company under Vifor Agreement No. 2 and the Maruishi Agreement during the three and six months ended June 30, 2024, respectively, in conjunction with ex-U.S. sales of KORSUVA/Kapruvia, which will be remitted to HCR under the terms of the HCR Agreement. This non-cash revenue will continue to be recorded until the Company has fulfilled its obligations under the HCR Agreement. There was no other revenue recorded for the three and six months ended June 30, 2023 as the HCR Agreement went into effect during the fourth quarter of 2023 (see Note 10, Royalty Purchase and Sale Agreement).

Contract balances

As of June 30, 2024 and December 31, 2023, the Company recorded accounts receivable, net – related party of $359 and $2,765, respectively, which primarily related to royalty payments from CSL Vifor in the current period and its

profit-sharing revenue from sales of KORSUVA injection in the United States by CSL Vifor, its commercial supply of KORSUVA injection to CSL Vifor, and royalty payments from CSL Vifor in the prior period. The Company also recorded $645 and $415 within other receivables which primarily related to royalty payments from Maruishi as of June 30, 2024 and December 31, 2023, respectively. There were no other contract assets or contract liabilities related to the CSL Vifor, Maruishi and CKDP agreements as of June 30, 2024 and December 31, 2023.

The Company routinely assesses the creditworthiness of its license and collaboration partners. The Company has not experienced any losses related to receivables from its license and collaboration partners as of June 30, 2024 and December 31, 2023.

- Definition

The entire disclosure of revenue from contract with customer to transfer good or service and to transfer nonfinancial asset. Includes, but is not limited to, disaggregation of revenue, credit loss recognized from contract with customer, judgment and change in judgment related to contract with customer, and asset recognized from cost incurred to obtain or fulfill contract with customer. Excludes insurance and lease contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-9

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-10

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 15
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-15

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-13

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Name Accounting Standards Codification
-Topic 606
-Publisher FASB
-URI https://asc.fasb.org//606/tableOfContent

+ Details

Stock-Based Compensation - Stock Option Compensation Expense (Detail) - Employee Stock Option [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Compensation expense	$ 1,420	$ 2,881	$ 3,153	$ 5,602
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Compensation expense	275	1,447	779	2,927
General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Compensation expense	$ 1,145	$ 1,434	$ 2,374	$ 2,675

Available-for-Sale Marketable Securities

6 Months Ended

Jun. 30, 2024

Available-for-Sale Marketable Securities

Available-for-Sale Marketable Securities

3. Available-for-Sale Marketable Securities

As of June 30, 2024, the Company’s available-for-sale marketable securities consisted of debt securities issued by U.S. government-sponsored entities. As of December 31, 2023, the Company’s available-for-sale marketable securities consisted of debt securities issued by the U.S. Treasury, U.S. government-sponsored entities and investment grade institutions (corporate bonds).

The following tables summarize the Company’s available-for-sale marketable securities by major type of security as of June 30, 2024 and December 31, 2023:

As of June 30, 2024


			Gross Unrealized				Estimated Fair
Type of Security	Amortized Cost		Gains		Losses		Value
U.S. government agency obligations	$	7,500	$	—	$	(121)	$	7,379
Total available-for-sale marketable securities	$	7,500	$	—	$	(121)	$	7,379

As of December 31, 2023


			Gross Unrealized				Estimated Fair
Type of Security	Amortized Cost		Gains		Losses		Value
U.S. Treasury securities	$	37,243	$	3	$	—	$	37,246
U.S. government agency obligations		7,500		—		(262)		7,238
Corporate bonds		4,500		—		(1)		4,499
Total available-for-sale marketable securities	$	49,243	$	3	$	(263)	$	48,983

The following tables summarize the fair value and gross unrealized losses of the Company’s available-for-sale marketable securities by investment category and disaggregated by the length of time that individual debt securities have been in a continuous unrealized loss position as of June 30, 2024 and December 31, 2023:

As of June 30, 2024


	Less than 12 Months				12 Months or Greater				Total
			Gross				Gross				Gross
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
	Value		Losses		Value		Losses		Value		Losses
U.S. government agency obligations	$	—	$	—	$	7,379	$	(121)	$	7,379	$	(121)
Total	$	—	$	—	$	7,379	$	(121)	$	7,379	$	(121)

As of December 31, 2023


	Less than 12 Months				12 Months or Greater				Total
			Gross				Gross				Gross
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
	Value		Losses		Value		Losses		Value		Losses
U.S. government agency obligations	$	—	$	—	$	7,238	$	(262)	$	7,238	$	(262)
Corporate bonds		—		—		2,000		(1)		2,000		(1)
Total	$	—	$	—	$	9,238	$	(263)	$	9,238	$	(263)

As of June 30, 2024 and December 31, 2023, no allowance for credit losses were recognized on the Company’s available-for-sale debt securities as no portion of the unrealized losses associated with those securities were due to credit losses. The information that the Company considered in reaching the conclusion that an allowance for credit losses was not necessary is as follows:

As of June 30, 2024 and December 31, 2023, the Company held a total of 2 out of 2 positions and 3 out of 9 positions, respectively, that were in an unrealized loss position, 2 of which had been in an unrealized loss position for 12 months or greater as of June 30, 2024. Unrealized losses individually and in aggregate, including any in an unrealized loss position for 12 months or greater, were not considered to be material for each respective period. Based on the Company’s review of these securities, the Company believes that the cost basis of its available-for-sale marketable securities is recoverable.

U.S. government agency obligations. The unrealized losses on the Company’s investments in direct obligations of U.S. government agencies were due to changes in interest rates and non-credit related factors. The credit ratings of these investments in the Company’s portfolio have not been downgraded below investment grade status. The contractual terms of these investments do not permit the issuer to repay principal at a price less than the amortized cost bases of the investments, which is equivalent to the par value on the maturity date. The Company expects to recover the entire amortized cost bases of these securities on the maturity date. The Company does not intend to sell these investments, and it is not “more likely than not” that the Company will be required to sell these investments before recovery of their amortized cost bases. The Company held 2 out of 2 positions for its U.S. government agency obligations that were in unrealized loss positions as of June 30, 2024.

The Company classifies its marketable debt securities based on their contractual maturity dates. As of June 30, 2024, the Company’s marketable debt securities mature at various dates through November 2024. The amortized cost and fair values of marketable debt securities by contractual maturity were as follows:


	As of June 30, 2024				As of December 31, 2023
Contractual maturity	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Less than one year	$	7,500	$	7,379	$	49,243	$	48,983
More than one year		—		—		—		—
Total	$	7,500	$	7,379	$	49,243	$	48,983

All available-for-sale marketable securities are classified as marketable securities, current or marketable securities, non-current depending on the contractual maturity date of the individual available-for-sale security. Other income, net includes interest and dividends, accretion/amortization of discounts/premiums, realized gains and losses on sales of securities and credit loss expense due to declines in the fair value of securities, if any. The cost of securities sold is based on the specific identification method.

There were no sales of available-for-sale marketable securities during each of the three and six months ended June 30, 2024 and 2023.

As of June 30, 2024 and December 31, 2023, accrued interest receivables on the Company’s available-for-sale debt securities were $119 and $139, respectively, and were included within other receivables.

Stock-Based Compensation

6 Months Ended

Jun. 30, 2024

Stock-Based Compensation

Stock-Based Compensation

15. Stock-Based Compensation

2019 Inducement Plan

In October 2019, the Company’s Board of Directors adopted the 2019 Inducement Plan, or the 2019 Plan, which is a non-stockholder approved stock plan adopted pursuant to the “inducement exception” provided under Nasdaq Listing Rule 5635(c)(4), or Rule 5635, for the purpose of awarding (i) non-statutory stock options, (ii) restricted stock awards, (iii) restricted stock unit awards, (iv) other stock awards (collectively, the Inducement Awards) to new employees of the Company, as inducement material to such new employees entering into employment with the Company. In November 2019, the Company filed a Registration Statement on Form S-8 with the SEC covering the offering of up to 300,000 shares of its common stock, par value $0.001, pursuant to the Company’s 2019 Plan. Initial grants of Inducement Awards made to employees vest as to 25% on the first anniversary of the date of grant and the balance ratably over the next 36 months and subsequent grants vest monthly over a period of four years from the grant date.

2014 Equity Incentive Plan

The Company’s 2014 Equity Incentive Plan, or the 2014 Plan, is administered by the Company’s Board of Directors or a duly authorized committee thereof, referred to as the Plan administrator. The 2014 Plan provides for the grant of incentive stock options, non-statutory stock options, restricted stock awards, restricted stock unit awards, stock appreciation rights, performance stock awards and other forms of equity compensation, collectively referred to as Stock Awards. Additionally, the 2014 Plan provides for the grant of performance cash awards. Incentive stock options may be granted only to employees. All other awards may be granted to employees, including officers, non-employee directors, and consultants. No incentive stock options may be granted under the 2014 Plan after the tenth anniversary of the effective date of the 2014 Plan. Stock Awards granted under the 2014 Plan vest at the rate specified by the Plan administrator. Initial grants of Stock Awards made to employees and non-employee consultants generally vest as to 25% on the first anniversary of the date of grant and the balance ratably over the next 36 months and subsequent grants generally vest monthly over a period of four years from the grant date, or upon the probable achievement of corporate goals. Stock options initially granted to members of the Company’s Board of Directors generally vest over a period of three years in equal quarterly installments from the date of the grant, subject to the option holder’s continued service as a director through such date. Subsequent grants to directors that are made automatically at Annual Meetings of Stockholders vest fully on the earlier of the first anniversary of the date of grant and the next Annual Meeting of Stockholders. The Plan administrator determines the term of Stock Awards granted under the 2014 Plan up to a maximum of ten years.

The aggregate number of shares of the Company’s common stock reserved for issuance under the 2014 Plan has automatically increased on January 1 of each year, beginning on January 1, 2015 and continued to increase on January 1 of each year through and including January 1, 2024, by 3% of the total number of shares of the Company’s capital stock outstanding on December 31 of the preceding calendar year, or a lesser number of shares determined by the Company’s Board of Directors. On January 1, 2024, the aggregate number of shares of common stock that may be issued pursuant to Stock Awards under the 2014 Plan automatically increased from 12,203,023 to 13,837,444. The maximum number of shares that may be issued pursuant to the exercise of incentive stock options under the 2014 Plan is 30,000,000 shares.

Restricted Stock Units

Under the 2014 Plan, there were 903,883 restricted stock units granted during each of the three and six months ended June 30, 2024. During the three and six months ended June 30, 2023, the Company granted 194,172 and 601,172 restricted stock units, respectively. No restricted stock units were granted under the 2019 Inducement Plan during the three and six months ended June 30, 2024 and 2023.

The weighted-average grant date fair value per share of restricted stock units granted to non-employee members of the Company’s Board of Directors during each of the three and six months ended June 30, 2024 was $0.66. The weighted-average grant date fair value per share of restricted stock units granted to employees and non-employee members of the Company’s Board of Directors during the three and six months ended June 30, 2023 was $3.09 and $7.81, respectively.

As of June 30, 2024, the Company’s restricted stock units consist of time-based restricted stock units. All remaining performance-based restricted stock units either vested or were forfeited in the first quarter of 2024. For time-based restricted stock units, the Company recognizes compensation expense associated with these restricted stock units ratably over the award’s vesting period following the grant date. For performance-based restricted stock units, vesting was contingent on the achievement of certain performance targets, subject to the recipient’s continuous service through each performance target. Recognition of compensation expense associated with these performance-based awards began when, and to the extent, the performance criteria were probable of achievement and the employee had met the service conditions.

During the three and six months ended June 30, 2024 and 2023, the Company recognized compensation expense relating to restricted stock units as follows:


	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2024			2023		2024	2023
Research and development	$	(6)	$	116	$	249	$	295
General and administrative		327		445		1,684		898
Total restricted stock unit expense	$	321	$	561	$	1,933	$	1,193

A summary of restricted stock unit activity related to employees and non-employee members of the Company’s Board of Directors as of and for the six months ended June 30, 2024 is presented below:


		Weighted
	Number of	Average Grant
	Units	Date Fair Value
Outstanding, December 31, 2023	566,324	$	9.27
Awarded	903,883		0.66
Vested and released	(357,060)		7.58
Forfeited	(136,348)		10.57
Outstanding, June 30, 2024	976,799	$	1.74
Restricted stock units exercisable (vested and deferred), June 30, 2024	—

Stock Options

Under the 2014 Plan, the Company granted 1,170,000 and 349,767 stock options during the three months ended June 30, 2024 and 2023, respectively, and 3,045,125 and 1,798,921 stock options during the six months ended June 30, 2024 and 2023, respectively. No stock options were granted under the 2019 Inducement Plan during the three and six months ended June 30, 2024 and 2023. The fair values of stock options granted during the three and six months ended June 30, 2024 and 2023 were estimated as of the dates of grant using the Black-Scholes option pricing model with the following assumptions:


	Three Months Ended		Six Months Ended
	June 30,		June 30,
	2024	2023	2024	2023
Risk-free interest rate	4.34%	3.38% - 3.89%	4.12% - 4.34%	3.38% - 4.22%
Expected volatility	89.8%	80.3% - 81.3%	89.6% - 89.8%	76.3% - 81.3%
Expected dividend yield	0%	0%	0%	0%
Expected life of employee and Board options (in years)	6.25	6.25	6.25	6.25

The weighted-average grant date fair value per share of options granted to employees and non-employee members of the Company’s Board of Directors for their Board service during the three months ended June 30, 2024 and 2023 was $0.66 and $2.43, respectively, and during the six months ended June 30, 2024 and 2023 was $0.86 and $6.18, respectively. No options were granted to non-employee consultants during the three and six months ended June 30, 2024 and 2023.

During the three and six months ended June 30, 2024 and 2023, the Company recognized compensation expense relating to stock options as follows:


	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2024		2023		2024		2023
Research and development	$	275	$	1,447	$	779	$	2,927
General and administrative		1,145		1,434		2,374		2,675
Total stock option expense	$	1,420	$	2,881	$	3,153	$	5,602

A summary of stock option award activity related to employees, non-employee members of the Company’s Board of Directors and non-employee consultants as of and for the six months ended June 30, 2024 is presented below:


		Weighted
	Number of	Average Exercise
	Shares	Price
Outstanding, December 31, 2023	7,897,647	$	12.99
Granted	3,045,125		0.86
Exercised	—		—
Forfeited	(3,139,154)		4.81
Expired	(1,735,737)		14.15
Outstanding, June 30, 2024	6,067,881	$	10.80
Options exercisable, June 30, 2024	3,797,495

The Company does not expect to realize any tax benefits from its stock option activity or the recognition of stock-based compensation expense because the Company currently has net operating losses and has a full valuation allowance against its deferred tax assets. Accordingly, no amounts related to excess tax benefits have been reported in cash flows from operations for each of the three and six months ended June 30, 2024 and 2023.

Stock-Based Compensation - Summary of Assumptions Used in Black-Scholes Option Pricing Model (Detail)	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	4.34%
Risk-free interest rate, minimum		3.38%	4.12%	3.38%
Risk-free interest rate, maximum		3.89%	4.34%	4.22%
Expected volatility	89.80%
Expected volatility, minimum		80.30%	89.60%	76.30%
Expected volatility, maximum		81.30%	89.80%	81.30%
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
Employee and Board of Directors Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life of options (in years)	6 years 3 months	6 years 3 months	6 years 3 months	6 years 3 months

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Operating activities
Net loss	$ (50,712)	$ (58,144)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	5,086	6,795
Non-cash interest expense on liability related to sales of future royalties and milestones, net of issuance costs accretion	3,892
Loss on inventory write-down	1,489
Depreciation and amortization	119	118
Noncash lease expense	525	759
Accretion of available-for-sale marketable securities, net	(543)	(56)
Changes in operating assets and liabilities:
Accounts receivable, net - related party	2,406	(6,864)
Inventory	(312)	(1,037)
Other receivables	(209)	76
Prepaid expenses	4,377	1,291
Accounts payable and accrued expenses	(11,102)	2,935
Operating lease liability		(936)
Reimbursement of lease incentive	2,094
Net cash used in operating activities	(42,890)	(55,063)
Investing activities
Proceeds from maturities of available-for-sale marketable securities	74,500	72,265
Proceeds from redemptions of available-for-sale marketable securities, at par		4,000
Purchases of available-for-sale marketable securities	(32,213)	(25,754)
Purchases of property and equipment	(1,046)
Net cash provided by investing activities	41,241	50,511
Financing activities
Payments to royalty purchase and sale agreement	(1,295)
Proceeds from the exercise of stock options		560
Net cash (used in) provided by financing activities	(1,295)	560
Net decrease in cash, cash equivalents and restricted cash	(2,944)	(3,992)
Cash, cash equivalents and restricted cash at beginning of period	53,683	64,149
Cash, cash equivalents and restricted cash at end of period	50,739	$ 60,157
Noncash investing and financing activities
Accrual for leasehold improvements	$ 19

Royalty Purchase and Sale Agreement (Details) - HCR Agreement [Member] $ in Thousands	1 Months Ended		3 Months Ended		6 Months Ended
	Dec. 31, 2023 USD ($)	Nov. 30, 2023 USD ($)	Jun. 30, 2024 USD ($)	Dec. 31, 2023 USD ($) agreement	Jun. 30, 2024 USD ($)
Royalty Purchase And Sale Agreement [Line Items]
Maximum consideration for royalties sold or agreed to sell				$ 40,000
Original upfront payment amount		$ 17,500
Net proceeds after transaction costs and advisory fees		$ 16,915
Net proceeds after advisory fees	$ 19,770
Original Milestone payment amount	$ 20,000
Additional Issuance costs				211
Net proceeds from the royalty purchase and sale agreement				36,474
Additional milestone payments to be earned			$ 2,500		$ 2,500
Issuance costs related to royalty purchase and sale agreement				$ 1,025
Payments			$ 610		$ 1,295
If the 2029 Threshold is achieved on or prior to December 31, 2029
Royalty Purchase And Sale Agreement [Line Items]
Threshold number of times of aggregate payments made by HCR, considered for termination of agreement \| agreement				2
If the 2029 Threshold is not achieved on or prior to December 31, 2029
Royalty Purchase And Sale Agreement [Line Items]
Threshold number of times of aggregate payments made by HCR, considered for termination of agreement \| agreement				2.8

Fair Value Measurements

6 Months Ended

Jun. 30, 2024

Fair Value Measurements

Fair Value Measurements

5. Fair Value Measurements

As of June 30, 2024 and December 31, 2023, the Company’s financial instruments consisted of cash, cash equivalents, available-for-sale marketable securities, accounts receivable, net – related party, prepaid expenses, restricted cash, accounts payable and accrued liabilities, and liability related to the sales of future royalties and milestones. The fair values of cash, cash equivalents, accounts receivable, net – related party, prepaid expenses, restricted cash, accounts payable and accrued liabilities approximate their carrying values due to the short-term nature of these financial instruments. The fair value of the liability related to the sales of future royalties and milestones also approximates the carrying value. Available-for-sale marketable securities are reported at their fair values, based upon pricing of securities with the same or similar investment characteristics as provided by third-party pricing services.

The Company validates the prices provided by its third-party pricing services by reviewing their pricing methods, obtaining market values from other pricing sources, and comparing them to the share prices presented by the third-party pricing services. After completing its validation procedures, the Company did not adjust or override any fair value measurements provided by its third-party pricing services as of June 30, 2024 or December 31, 2023.

The following tables summarize the Company’s financial assets measured at fair value on a recurring basis as of June 30, 2024 and December 31, 2023.

Fair value measurement as of June 30, 2024:


			Quoted prices in		Significant other		Significant
Financial assets			active markets for		observable		unobservable
			identical assets		inputs		inputs
Type of Instrument	Total		(Level 1)		(Level 2)		(Level 3)
Cash and cash equivalents:
Money market funds and checking accounts	$	49,239	$	49,239	$	—	$	—
Available-for-sale marketable securities:
U.S. government agency obligations		7,379		—		7,379		—
Restricted cash:
Commercial money market account		1,500		1,500		—		—
Total financial assets	$	58,118	$	50,739	$	7,379	$	—

Fair value measurement as of December 31, 2023:


			Quoted prices in		Significant other		Significant
Financial assets			active markets for		observable		unobservable
			identical assets		inputs		inputs
Type of Instrument	Total		(Level 1)		(Level 2)		(Level 3)
Cash and cash equivalents:
Money market funds and checking accounts	$	51,775	$	51,775	$	—	$	—
Available-for-sale marketable securities:
U.S. Treasury securities		37,246		—		37,246		—
U.S. government agency obligations		7,238		—		7,238		—
Corporate bonds		4,499		—		4,499		—
Restricted cash:
Commercial money market account		1,908		1,908		—		—
Total financial assets	$	102,666	$	53,683	$	48,983	$	—

There were no purchases, sales or maturities of Level 3 financial assets and no unrealized gains or losses related to Level 3 available-for-sale marketable securities during each of the three and six months ended June 30, 2024 and 2023. There were no transfers of financial assets into or out of Level 3 classification during each the three and six months ended June 30, 2024 and 2023.

- 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 + Details

Net Loss per Share - Computation of Denominators Used in Net Loss per Share (Detail) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Basic:
Weighted average common shares outstanding - Basic	54,724,692	54,002,988	54,656,391	53,937,875
Diluted:
Weighted average common shares outstanding - Basic	54,724,692	54,002,988	54,656,391	53,937,875
Common stock equivalents	0	0	0	0
Denominator for diluted net loss per share	54,724,692	54,002,988	54,656,391	53,937,875

Restricted Cash - Schedule of Reconciliation of Cash, Cash Equivalents and Restricted Cash (Detail) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023	Jun. 30, 2023	Dec. 31, 2022
Restricted Cash
Cash and cash equivalents	$ 49,239	$ 51,775
Restricted cash, current assets		408
Restricted cash, long-term assets	1,500	1,500
Total cash, cash equivalents, and restricted cash shown in the Condensed Consolidated Statements of Cash Flows	$ 50,739	$ 53,683	$ 60,157	$ 64,149

Net Loss Per Share - Additional Information (Detail) - shares	Jun. 30, 2024	Dec. 31, 2023	Jun. 30, 2023
Number of options outstanding	6,067,881	7,897,647
Employee Stock Option
Number of options outstanding	6,067,881		8,134,597
Restricted Stock Units [Member]
Number of restricted stock units outstanding	976,799		791,853

Inventory, net

6 Months Ended

Jun. 30, 2024

Inventory, net

Inventory, net

7. Inventory, net

Inventory, net consists of the following:


	June 30, 2024		December 31, 2023
Raw materials	$	2,124	$	2,639
Work-in-process		1,009		708
		3,133		3,347
Less Inventory Reserve for Obsolescence		(1,489)		(526)
Total	$	1,644	$	2,821

As of June 30, 2024 and December 31, 2023, inventory balances include inventory costs subsequent to regulatory approval of KORSUVA injection on August 23, 2021. During the three and six months ended June 30, 2024, the Company wrote down $1,489 of commercial supply inventory due to obsolescence.

Document and Entity Information - shares	6 Months Ended
Document and Entity Information - shares	Jun. 30, 2024	Aug. 09, 2024
Document And Entity Information [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2024
Document Transition Report	false
Entity File Number	001-36279
Entity Registrant Name	CARA THERAPEUTICS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	75-3175693
Entity Address, Postal Zip Code	06901
Entity Address, Address Line One	400 Atlantic Street
Entity Address, Address Line Two	Suite 500
Entity Address, City or Town	Stamford
Entity Address, State or Province	CT
City Area Code	203
Local Phone Number	406-3700
Title of 12(b) Security	Common Stock, par value $0.001 per share
Trading Symbol	CARA
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	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		54,846,639
Entity Central Index Key	0001346830
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q2
Amendment Flag	false

Fair Value Measurements - Summary of Financial Assets Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Financial assets
Available-for-sale marketable securities	$ 7,379	$ 48,983
Recurring [Member]
Financial assets
Total financial assets	58,118	102,666
U.S. Treasury Securities [Member]
Financial assets
Available-for-sale marketable securities		37,246
U.S. Treasury Securities [Member] \| Recurring [Member]
Financial assets
Available-for-sale marketable securities		37,246
U.S. Government Agency Obligations [Member]
Financial assets
Available-for-sale marketable securities	7,379	7,238
U.S. Government Agency Obligations [Member] \| Recurring [Member]
Financial assets
Available-for-sale marketable securities	7,379	7,238
Corporate Bonds [Member]
Financial assets
Available-for-sale marketable securities		4,499
Corporate Bonds [Member] \| Recurring [Member]
Financial assets
Available-for-sale marketable securities		4,499
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Recurring [Member]
Financial assets
Total financial assets	50,739	53,683
Significant Other Observable Inputs (Level 2) [Member] \| Recurring [Member]
Financial assets
Total financial assets	7,379	48,983
Significant Other Observable Inputs (Level 2) [Member] \| U.S. Treasury Securities [Member] \| Recurring [Member]
Financial assets
Available-for-sale marketable securities		37,246
Significant Other Observable Inputs (Level 2) [Member] \| U.S. Government Agency Obligations [Member] \| Recurring [Member]
Financial assets
Available-for-sale marketable securities	7,379	7,238
Significant Other Observable Inputs (Level 2) [Member] \| Corporate Bonds [Member] \| Recurring [Member]
Financial assets
Available-for-sale marketable securities		4,499
Money Market Funds [Member] \| Recurring [Member]
Financial assets
Cash and cash equivalents	49,239	51,775
Restricted cash	1,500	1,908
Money Market Funds [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Recurring [Member]
Financial assets
Cash and cash equivalents	49,239	51,775
Restricted cash	$ 1,500	$ 1,908

Prepaid expenses - Additional Information (Detail) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Prepaid expenses
Prepaid expenses	$ 3,777	$ 8,154
Prepaid R&D clinical costs	2,458	7,245
Prepaid insurance	1,021	492
Other prepaid costs	$ 298	$ 417

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Income Taxes
Company's effective tax rate	0.00%	0.00%	0.00%	0.00%
Income tax receivable related to R&D credit	$ 697		$ 697
Percentage of eligible annual research and development credit for cash	65.00%		65.00%
Benefit from income taxes	$ 0	$ 0	$ 0	$ 0

- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References + Details

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS
Other comprehensive income tax	$ 0	$ 0	$ 0	$ 0

- Definition

Amount of tax expense (benefit) allocated to other comprehensive income (loss).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 12
-SubTopic 10
-Topic 220
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482790/220-10-45-12

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482765/220-10-50-4

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 830
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481674/830-30-50-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 830
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 17
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481694/830-30-45-17

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 830
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 20
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481694/830-30-45-20

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(19))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483586/944-220-S99-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-10

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 11
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482659/740-20-45-11

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(21))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483621/220-10-S99-2

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(23))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483589/942-220-S99-1

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482659/740-20-45-2

+ Details

Stock-Based Compensation - Restricted Stock Unit Activity (Details) - Restricted Stock Units [Member] - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Non-employee Directors [Member]
Weighted Average Grant Date Fair Value
Weighted-average grant date fair value, awarded	$ 0.66		$ 0.66
Employees And Non-Employee Members Of Board Of Directors [Member]
Weighted Average Grant Date Fair Value
Weighted-average grant date fair value, awarded		$ 3.09		$ 7.81
2014 Equity Incentive Plan [Member]
Number of Units
Awarded	903,883	194,172	903,883	601,172
2014 Equity Incentive Plan [Member] \| Employees And Non-Employee Members Of Board Of Directors [Member]
Number of Units
Outstanding, Beginning Balance			566,324
Awarded			903,883
Vested and released			(357,060)
Forfeited			(136,348)
Outstanding, Ending Balance	976,799		976,799
Weighted Average Grant Date Fair Value
Weighted-average grant date fair value, outstanding, Beginning Balance			$ 9.27
Weighted-average grant date fair value, awarded			0.66
Weighted-average grant date fair value, vested and released			7.58
Weighted-average grant date fair value, forfeited			10.57
Weighted-average grant date fair value, outstanding, Ending Balance	$ 1.74		$ 1.74

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2024	Jun. 30, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ (20,016)	$ (30,696)	$ (31,479)	$ (26,665)	$ (50,712)	$ (58,144)

- Definition

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

+ References

+ Details

Collaboration and Licensing Agreements

6 Months Ended

Jun. 30, 2024

Collaboration and Licensing Agreements.

Collaboration and Licensing Agreements

12. Collaboration and Licensing Agreements

Vifor (International) Ltd. (Vifor International)

In October 2020, the Company entered into a license agreement with Vifor International, or Vifor Agreement No. 1, under which the Company granted Vifor International an exclusive license solely in the United States to use, distribute, offer for sale, promote, sell and otherwise commercialize difelikefalin injection for all therapeutic uses relating to the inhibition, prevention or treatment of itch associated with pruritus in hemodialysis and peritoneal dialysis patients in the United States. Under Vifor Agreement No. 1, the Company retains all rights with respect to the clinical development of, and activities to gain regulatory approvals of, difelikefalin injection in the United States.

After the assignment of rights of Vifor Agreement No. 1 from Vifor International to Vifor Fresenius Medical Care Renal Pharma Ltd. in May 2022, Vifor Agreement No. 1 provides full commercialization rights in dialysis clinics to CSL Vifor in the United States under a profit-sharing arrangement. Pursuant to the profit-sharing arrangement, the Company is generally entitled to 60% of the net profits (as defined in Vifor Agreement No. 1) from sales of difelikefalin injection in the United States and CSL Vifor is entitled to 40% of such net profits (excluding sales to Fresenius Medical Center dialysis clinics, compensation for which is governed by Vifor Agreement No. 2, as defined below), subject to potential temporary adjustment in future years based on certain conditions. Under Vifor Agreement No. 1, in consideration of CSL Vifor’s conduct of the marketing, promotion, selling and distribution of difelikefalin injection in the United States, the Company pays a marketing and distribution fee to CSL Vifor based on the level of annual net

sales. This fee as well as CSL Vifor’s cost of goods sold, or COGS, are deducted from net sales in calculating the net profits that are subject to the profit-sharing arrangement under Vifor Agreement No. 1.

In addition, pursuant to Vifor Agreement No. 1, the Company is eligible to receive payments of up to $240,000 upon the achievement of certain sales-based milestones.

The Company retains the rights to make and have made difelikefalin injection, or the Licensed Product, on a non-exclusive basis, in the United States for commercial sale of the Licensed Product for use in all therapeutic areas to prevent, inhibit or treat itch associated with pruritus in hemodialysis and peritoneal-dialysis patients, or the Field, anywhere in the world and for supply of Licensed Product to CSL Vifor under the terms of a supply agreement, or the Vifor International Supply Agreement, which was executed in September 2021. The supply price is the Company’s COGS, as calculated under GAAP, plus an agreed upon margin. The Vifor International Supply Agreement will co-terminate with Vifor Agreement No. 1. The Company also retains the rights to import, distribute, promote, sell and otherwise commercialize the Licensed Product on an exclusive basis outside of the Field either in or outside of the United States.

The Vifor International Supply Agreement is accounted for as a customer option that is not a material right because the selling price of the Licensed Product under the Vifor International Supply Agreement is the Company’s COGS plus an agreed upon margin, which is commensurate with the “COGS plus” model that the Company would charge other parties under similar agreements (the standalone selling price) and not at a discount. Therefore, the sale of commercial supply to CSL Vifor is not a performance obligation under Vifor Agreement No. 1 but rather the Vifor International Supply Agreement is a separate agreement from Vifor Agreement No. 1. The only performance obligation under the Vifor International Supply Agreement is the delivery of the Licensed Product to CSL Vifor for commercialization.

Vifor Fresenius Medical Care Renal Pharma Ltd.

In May 2018, the Company entered into a license agreement with Vifor Fresenius Medical Care Renal Pharma Ltd., or Vifor Agreement No. 2, under which the Company granted Vifor Fresenius Medical Care Renal Pharma Ltd. an exclusive, royalty-bearing license, or the Vifor License, to seek regulatory approval to commercialize, import, export, use, distribute, offer for sale, promote, sell and otherwise commercialize the Licensed Product in the Field worldwide (excluding the United States, Japan and South Korea), or the Territory.

The Company is eligible to receive from Vifor Fresenius Medical Care Renal Pharma Ltd. additional commercial milestone payments in the aggregate of up to $440,000, all of which are sales related. The Company is also eligible to receive tiered double-digit royalty payments based on annual net sales, as defined in Vifor Agreement No. 2, of difelikefalin injection in the licensed territories. The Company retained full commercialization rights for difelikefalin injection for the treatment of chronic kidney disease associated pruritus in the United States except in the dialysis clinics of FMCNA, where Vifor Fresenius Medical Care Renal Pharma Ltd. will promote difelikefalin injection under a profit-sharing arrangement (as defined in Vifor Agreement No. 2), based on net FMCNA clinic sales (as defined in Vifor Agreement No. 2) and the Company and Vifor Fresenius Medical Care Renal Pharma Ltd. are each entitled to 50% of such net profits, subject to potential adjustments in a calendar year based on certain conditions.

The Company retains the rights to make and have made the Licensed Product in the Territory for commercial sale by Vifor Fresenius Medical Care Renal Pharma Ltd. in the Field in or outside the Territory and for supply of Licensed Product to Vifor Fresenius Medical Care Renal Pharma Ltd. under the terms of a supply agreement, or the Vifor Supply Agreement, which was executed in May 2020. The supply price is the Company’s COGS, as calculated under GAAP, plus an agreed upon margin. The Vifor Supply Agreement will co-terminate with Vifor Agreement No. 2.

The Vifor Supply Agreement is accounted for as a customer option that is not a material right because the selling price of the Licensed Product under the Vifor Supply Agreement is the Company’s COGS plus an agreed upon margin, which is commensurate with the “COGS plus” model that the Company would charge other parties under similar agreements (the standalone selling price) and not at a discount. Therefore, the sale of compound to Vifor Fresenius Medical Care Renal Pharma Ltd. is not a performance obligation under Vifor Agreement No. 2 but rather the Vifor Supply Agreement is a separate agreement from Vifor Agreement No. 2. The only performance obligation under the Vifor Supply Agreement is the delivery of the Licensed Product to Vifor Fresenius Medical Care Renal Pharma Ltd. for commercialization.

Maruishi Pharmaceutical Co., Ltd. (Maruishi)

In April 2013, the Company entered into a license agreement with Maruishi, or the Maruishi Agreement, under which the Company granted Maruishi an exclusive license to develop, manufacture, and commercialize drug products containing difelikefalin for acute pain and/or uremic pruritus in Japan. Maruishi has the right to grant sub-licenses in Japan, which entitles the Company to receive sub-license fees, net of prior payments made by Maruishi to the Company. Under the Maruishi Agreement, the Company and Maruishi are required to use commercially reasonable efforts, at their own expense, to develop, obtain regulatory approval for and commercialize difelikefalin in the United States and Japan, respectively. In addition, the Company provided Maruishi specific clinical development services for difelikefalin used in Maruishi’s field of use.

Under the terms of the Maruishi Agreement, the Company is eligible to receive milestone payments upon the achievement of defined clinical and regulatory events as well as tiered, low double-digit royalties with respect to any sales of the licensed product sold in Japan by Maruishi, if any, and share in any sub-license fees.

In September 2022, Maruishi submitted a New Drug Application in Japan for approval of difelikefalin injection for the treatment of pruritus in hemodialysis patients. In September 2023, Maruishi received manufacturing and marketing approval from Japan’s Ministry of Health, Labour and Welfare for KORSUVA IV Injection Syringe for the treatment of pruritus in hemodialysis patients. In November 2023, the Company entered into an API supply agreement with Maruishi for difelikefalin.

Chong Kun Dang Pharmaceutical Corporation (CKDP)

In April 2012, the Company entered into a license agreement with CKDP, or the CKDP Agreement, in South Korea, under which the Company granted CKDP an exclusive license to develop, manufacture and commercialize drug products containing difelikefalin in South Korea. The Company and CKDP are each required to use commercially reasonable efforts, at their respective expense, to develop, obtain regulatory approval for and commercialize difelikefalin in the United States and South Korea, respectively.

Under the terms of the CKDP Agreement, the Company is eligible to receive milestone payments upon the achievement of defined clinical and regulatory events as well as tiered royalties, with percentages ranging from the high single digits to the high teens, based on net sales of products containing difelikefalin in South Korea, if any, and share in any sub-license fees.

Accumulated Other Comprehensive Loss (Tables)

6 Months Ended

Jun. 30, 2024

Accumulated Other Comprehensive Loss

Summary of Changes in Accumulated Other Comprehensive (Loss) Income, Net of Tax, from Unrealized Gains (Losses) on Available-for-Sale Marketable Securities


	Total Accumulated
	Other Comprehensive
	Loss
Balance, December 31, 2023	$	(260)
Other comprehensive income before reclassifications		139
Amount reclassified from accumulated other comprehensive loss		—
Net current period other comprehensive income		139
Balance, June 30, 2024	$	(121)

Balance, December 31, 2022	$	(1,672)
Other comprehensive income before reclassifications		942
Amount reclassified from accumulated other comprehensive loss		—
Net current period other comprehensive income		942
Balance, June 30, 2023	$	(730)

Stock-Based Compensation - Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Stock-Based Compensation
Number of Options, Outstanding, Beginning Balance			7,897,647
Number of Options, Granted			3,045,125
Number of Options, Forfeited			(3,139,154)
Number of Options, Expired			(1,735,737)
Number of Options, Outstanding, Ending Balance	6,067,881		6,067,881
Number of Options, Options exercisable	3,797,495		3,797,495
Weighted-Average Exercise Price, Outstanding, Beginning Balance			$ 12.99
Weighted-Average Exercise Price, Granted			0.86
Weighted-Average Exercise Price, Forfeited			4.81
Weighted-Average Exercise Price, Expired			14.15
Weighted-Average Exercise Price, Outstanding, Ending Balance	$ 10.80		$ 10.80
Excess tax benefits from stock option activity or stock-based compensation expense recognized in cash flows from operations	$ 0	$ 0	$ 0	$ 0

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Jun. 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

Net Loss per Share (Tables)

6 Months Ended

Jun. 30, 2024

Net Loss Per Share

Computation of Denominators Used in Net Loss per Share

The denominators used in the net loss per share computations are as follows:


	Three Months Ended		Six Months Ended
	June 30,		June 30,
	2024	2023	2024	2023
Basic:
Weighted average common shares outstanding	54,724,692	54,002,988	54,656,391	53,937,875
Diluted:
Weighted average common shares outstanding - Basic	54,724,692	54,002,988	54,656,391	53,937,875
Common stock equivalents*	—	—	—	—
Denominator for diluted net loss per share	54,724,692	54,002,988	54,656,391	53,937,875

*	No amounts were considered as their effects would be anti-dilutive.

Computation of Basic and Diluted Net Loss per Share

Basic and diluted net loss per share are computed as follows:


	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2024		2023		2024		2023
Net loss - basic and diluted	$	(20,016)	$	(31,479)	$	(50,712)	$	(58,144)
Weighted-average common shares outstanding:
Basic and diluted		54,724,692		54,002,988		54,656,391		53,937,875
Net loss per share, basic and diluted:	$	(0.37)	$	(0.58)	$	(0.93)	$	(1.08)

Commitments and Contingencies (Tables)

6 Months Ended

Jun. 30, 2024

Commitments and Contingencies


Total expense recorded in the three months ended March 31, 2024	$	2,401
Payments made in the three months ended March 31, 2024		(1,702)
Remaining amounts to be paid as of March 31, 2024		699
Total expense recorded in the three months ended June 30, 2024		2,581
Payments made in the three months ended June 30, 2024		(301)
Remaining amounts to be paid as of June 30, 2024	$	2,979

Schedule of Other Information related to Stamford Lease, Lease Amendment and New Lease


	Three Months Ended June 30,						Six Months Ended June 30,
	2024			2023			2024			2023
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash outflows relating to operating leases	$	—		$	496		$	—		$	990
ROU assets obtained in exchange for new operating lease liabilities	$	—		$	—		$	—		$	—
Remaining lease term - operating leases (years)		10.3			0.5			10.3			0.5
Discount rate - operating leases		12.8	%		7.0	%		12.8	%		7.0	%

Schedule of Future Minimum Lease Payments under Non-cancellable Operating Leases, Reconciliation of Undiscounted Cash Flows to the Operating Lease Liabilities


Year Ending December 31,
2024 (Excluding the six months ended June 30, 2024)	$	108
2025		1,298
2026		1,330
2027		1,363
2028		1,398
Thereafter		8,874
Total future minimum lease payments, undiscounted		14,371
Less imputed interest		(6,883)
Total	$	7,488

Operating lease liability reported as of June 30, 2024:
Operating lease liability - current	$	168
Operating lease liability - non-current		7,320
Total	$	7,488

Restricted Cash (Tables)

6 Months Ended

Jun. 30, 2024

Restricted Cash

Schedule of Reconciliation of Cash, Cash Equivalents and Restricted Cash


	June 30, 2024		December 31, 2023
Cash and cash equivalents	$	49,239	$	51,775
Restricted cash, current assets		—		408
Restricted cash, long-term assets		1,500		1,500
Total cash, cash equivalents, and restricted cash shown in the Condensed Consolidated Statements of Cash Flows	$	50,739	$	53,683

Commitments and Contingencies - Additional Information (Detail) $ in Thousands			1 Months Ended		3 Months Ended		6 Months Ended
	Jul. 28, 2023 USD ($)	May 11, 2023 USD ($)	Jul. 31, 2021	Jul. 31, 2019 agreement	Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($)	Dec. 31, 2023 USD ($)
Other Commitments [Line Items]
Accounts payable and accrued expenses					$ 13,733		$ 13,733		$ 25,592
Operating lease liabilities					7,488		7,488
Operating lease right-of-use assets					3,646		3,646		4,864
Research and development					9,308	$ 30,310	31,272	$ 54,644
New Corporate Headquarters Office Space
Other Commitments [Line Items]
Lease, annual fixed rent		$ 1,300
Lease, fixed rent, annual increase, percent		2.50%
Option to extend		true
Operating Lease, renewable term		5 years
Discount rate - operating leases		12.83%
Operating lease liabilities	$ 6,672
Lessee, operating lease, incentives	2,900
Operating lease right-of-use assets	$ 6,779
Lease incentives reimbursed					368		2,094
Lease incentives remaining to be reimbursed					0		0
Operating Lease, expense					256		525
New Corporate Headquarters Office Space \| Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Other Commitments [Line Items]
Lessee, operating lease, discount rate, basis spread on variable rate		7.75%
Lessee, operating lease, discount rate, variable rate basis, floor		2.75%
New Corporate Headquarters Office Space \| Research and Development
Other Commitments [Line Items]
Operating Lease, expense					195		368
New Corporate Headquarters Office Space \| General and Administrative
Other Commitments [Line Items]
Operating Lease, expense					61		157
Patheon and Patheon Manufacturing Services LLC
Other Commitments [Line Items]
Reduced demand payment for manufacturing commitments									$ 1,700
Accounts payable and accrued expenses					246		246
Old Stamford Operating Lease
Other Commitments [Line Items]
Operating lease cost					0	406	0	813
Old Stamford Operating Lease \| Research and Development
Other Commitments [Line Items]
Operating lease cost						284		569
Old Stamford Operating Lease \| General and Administrative
Other Commitments [Line Items]
Operating lease cost						122		244
New Stamford Lease
Other Commitments [Line Items]
Letter of credit amount outstanding					1,500		1,500
Non-Exclusive License Agreement \| Enteris Biopharma, Inc.
Other Commitments [Line Items]
Payment of milestone payment					$ 0	$ 0	$ 0	$ 0
MSA \| Patheon and Patheon Manufacturing Services LLC
Other Commitments [Line Items]
Number of related product agreements \| agreement				2
API Commercial Supply Agreement - PPL
Other Commitments [Line Items]
Agreement renewal term			5 years

Accounts Payable and Accrued Expenses

6 Months Ended

Jun. 30, 2024

Accounts Payable and Accrued Expenses

Accounts Payable and Accrued Expenses

9. Accounts Payable and Accrued Expenses

Accounts payable and accrued expenses consist of the following:


	June 30, 2024		December 31, 2023
Accounts payable	$	6,755	$	11,583
Accrued research projects		1,010		4,343
Accrued compensation and benefits		1,214		6,519
Accrued professional fees and other		4,754		3,147
Total	$	13,733	$	25,592

Royalty Purchase and Sale Agreement - Summarizes the Activity of the HCR Agreement (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2024
Royalty Purchase And Sale Agreement [Line Items]
Royalty purchase and sale agreement balance at December 31, 2023		$ 37,079
Non-cash interest expense	$ 1,910	3,892
Balance at June 30, 2024	39,676	39,676
HCR Agreement [Member]
Royalty Purchase And Sale Agreement [Line Items]
Royalty purchase and sale agreement balance at December 31, 2023		37,079
Payments	(610)	(1,295)
Non-cash interest expense		3,892
Balance at June 30, 2024	$ 39,676	$ 39,676
Effective interest rate	20.95%	20.95%

Income Taxes

6 Months Ended

Jun. 30, 2024

Income Taxes

Income Taxes

16. Income Taxes

The Company has recognized a full tax valuation allowance against its deferred tax assets as of June 30, 2024 and December 31, 2023. The tax benefit related to the exercise of stock options is recognized as a deferred tax asset that is offset by a corresponding valuation allowance. As such, the Company’s effective tax rate is zero for each of the three and six months ended June 30, 2024 and 2023.

Historically, the Company’s benefit from income taxes related to state R&D tax credits exchanged for cash pursuant to the Connecticut R&D Tax Credit Exchange Program, which permits qualified small businesses engaged in R&D activities within Connecticut to exchange their unused R&D tax credits for a cash amount equal to 65% of the value of the exchanged credits. The Company has not exchanged its R&D tax credit for cash during the three and six months ended June 30, 2024, and it was not eligible to exchange its R&D tax credit for cash during the three and six months ended June 30, 2023. Therefore, there was no benefit from income taxes for either of the three and six months ended June 30, 2024 and 2023. As of June 30, 2024, the Company recorded $697 within income tax receivable which related to the 2020 R&D credit.

The Inflation Reduction Act of 2022 included tax legislation that became effective early in 2023. Significant legislation for corporate taxpayers includes a corporate alternative minimum tax of 15.0% for companies with $1,000,000 or more in average net financial statement profits over the three previous years, as well as a 1.0% indirect excise tax on the repurchase of shares by a publicly traded company. The Company does not expect this legislation to have an effect on its tax provision as of June 30, 2024; however, the Company will continue to evaluate the effect on the tax provision each reporting period.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-13

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(2))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//740/tableOfContent

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-14

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 21
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-21

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 270
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482526/740-270-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 17
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-17

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I.5.Q1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479360/740-10-S99-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 11.C)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479360/740-10-S99-2

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482603/740-30-50-2

+ Details

Available-for-Sale Marketable Securities - Additional Information (Detail) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2024 USD ($) position	Dec. 31, 2023 USD ($) position
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale allowance for credit loss \| $	$ 0	$ 0
Available-for-sale unrealized credit losses \| $	$ 0	$ 0
Number of available-for-sale marketable securities in unrealized loss positions	2	3
Total number of positions	2	9
Number of positions of available-for-sale in unrealized loss position for 12 months or greater	2
U.S. Government Agency Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Number of available-for-sale marketable securities in unrealized loss positions	2
Total number of positions	2

- 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

Commitments and Contingencies - Schedule of Other Information related to Stamford Lease and New Stamford Lease (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Commitments and Contingencies
Operating cash outflows relating to operating leases		$ 496		$ 990
ROU assets obtained in exchange for new operating lease liabilities
Remaining lease term - operating leases (years)	10 years 3 months 18 days	6 months	10 years 3 months 18 days	6 months
Discount rate - operating leases	12.80%	7.00%	12.80%	7.00%

Commitments and Contingencies

6 Months Ended

Jun. 30, 2024

Commitments and Contingencies

Commitments and Contingencies

17. Commitments and Contingencies

License Agreement with Enteris Biopharma, Inc.

In August 2019, the Company entered into a non-exclusive license agreement, or the Enteris License Agreement, with Enteris Biopharma, Inc., or Enteris, pursuant to which Enteris granted to the Company a non-exclusive, royalty-bearing license, including the right to grant sublicenses, under certain proprietary technology and patent rights related to or covering formulations for oral delivery of peptide active pharmaceutical ingredients with functional excipients to enhance permeability and/or solubility, known as Enteris’s Peptelligence^® technology, to develop, manufacture and commercialize products using such technology worldwide, excluding Japan and South Korea.

The Company is also obligated, pursuant to the Enteris License Agreement, to pay Enteris (1) milestone payments upon the achievement of certain development, regulatory and commercial milestones and (2) low-single digit royalty percentages on net sales of licensed products, subject to reductions in specified circumstances. During the three and six months ended June 30, 2024 and 2023, no milestone payments or royalties were paid to Enteris by the Company in relation to the Enteris License Agreement.

Manufacturing Agreements

In July 2021, the Company entered into an API Commercial Supply Agreement with Polypeptide Laboratories S.A., or PPL, that defines each party’s responsibilities with respect to PPL’s manufacture and supply of the active pharmaceutical ingredient difelikefalin, or API, for the difelikefalin injection product candidate. Under the API Commercial Supply Agreement, PPL shall manufacture API at its facility for sale and supply to the Company, in the amounts as set forth in purchase orders to be provided by the Company. The Company will be required to purchase its requirements of API for each year of the term of the agreement, based on internal forecasts.

The API Commercial Supply Agreement will continue until the fifth anniversary of the approval by the FDA of the new drug application for KORSUVA injection, unless the API Commercial Supply Agreement is earlier terminated, and will automatically be extended for successive five-year periods unless either party gives notice to the other party of its intention to terminate.

In July 2019, the Company entered into a Master Manufacturing Services Agreement, or MSA, with Patheon UK Limited, or Patheon. The MSA governs the general terms under which Patheon, or one of its affiliates, will provide non-exclusive manufacturing services to the Company for the drug products specified by the Company from time to time. Pursuant to the MSA, the Company has agreed to order from Patheon at least a certain percentage of its commercial requirements for a product under a related Product Agreement. Each Product Agreement that the Company may enter into from time to time will be governed by the terms of the MSA, unless expressly modified in such Product Agreement.

In July 2019, the Company entered into two related Product Agreements under the MSA, one with each of Patheon and Patheon Manufacturing Services LLC, or Patheon Greenville, to govern the terms and conditions of the manufacture of commercial supplies of difelikefalin injection, the Company’s lead product candidate. Pursuant to the Product Agreements, Patheon and Patheon Greenville will manufacture commercial supplies of difelikefalin injection at the Monza, Italy and Greenville, North Carolina manufacturing sites, respectively, from active pharmaceutical ingredient supplied by the Company. Patheon and Patheon Greenville will be responsible for supplying the other required raw materials and packaging components, and will also provide supportive manufacturing services such as quality control testing for raw materials, packaging components and finished product.

In December 2023, the Company entered into an agreement with Patheon to reimburse Patheon approximately $1,700 for forecasted manufacturing commitments that are no longer needed due to the reduced demand expectations of KORSUVA in the United States. As of June 30, 2024, $246 remained within accounts payable and accrued expenses on its Condensed Consolidated Balance Sheet. In connection with the agreement with Patheon, the Company agreed to schedule additional manufacturing commitments in 2024.

Restructuring Actions

In January 2024, the Company announced a workforce reduction of up to 50% of its employees in order to reduce its operating expenses and focus its efforts on development of oral difelikefalin in chronic pruritus associated with NP. As a result, the Company made estimates and judgements regarding its future plans, including future employee termination costs to be incurred in conjunction with involuntary separations when such separations are probable and estimable. In the first quarter of 2024, the Company recorded a pre-tax severance expense of $2,401, which was included within restructuring expenses on the Condensed Consolidated Statements of Comprehensive Loss for the six months ended June 30, 2024. The remaining amounts to be paid as of June 30, 2024 are included within accounts payable and accrued expenses on the Condensed Consolidated Balance Sheet.

In connection with the streamlined operating plan approved by the Board of Directors in June 2024 (see Note 1, Business), the Board of Directors also approved a second reduction in the Company’s workforce by approximately 70%, which the Company substantially completed by June 30, 2024. As a result, the Company made additional estimates and judgments regarding its future plans, including future employee termination costs to be incurred in conjunction with involuntary separations when such separations are probable and estimable. During the three months ended June 30, 2024, the Company recorded a pre-tax severance expense of $2,581, which was included within restructuring expenses on the Condensed Consolidated Statements of Comprehensive Loss for each of the three and six months ended June 30, 2024. The remaining amounts to be paid as of June 30, 2024 are included within accounts payable and accrued expenses on the Condensed Consolidated Balance Sheet.

The detail of activity related to the Company’s restructuring action is as follows:


Total expense recorded in the three months ended March 31, 2024	$	2,401
Payments made in the three months ended March 31, 2024		(1,702)
Remaining amounts to be paid as of March 31, 2024		699
Total expense recorded in the three months ended June 30, 2024		2,581
Payments made in the three months ended June 30, 2024		(301)
Remaining amounts to be paid as of June 30, 2024	$	2,979

Leases (Original Corporate Headquarters in 2015 & Amendment for Additional Space in 2020)

Lease expense was recognized on a straight-line basis over the lease term of the Company’s previous lease agreements for its original headquarters, and additional office space, in Stamford, Connecticut. As a result, $406 and $813 of operating lease cost, or lease expense, was recognized for the three and six months ended June 30, 2023, respectively, consisting of $284 relating to R&D lease expense and $122 relating to G&A lease expense for the three months ended June 30, 2023, and $569 relating to R&D lease expense and $244 relating to G&A lease expense for the six months ended June 30, 2023. There was no lease expense recognized on these former lease agreements for the three and six months ended June 30, 2024 since these agreements terminated in December 2023.

Lease (New Corporate Headquarters in May 2023)

On May 11, 2023, the Company entered into the New Lease for the Company’s new principal executive offices. The initial term of the New Lease commenced on November 1, 2023, or the Commencement Date, and will expire on the last day of the calendar month in which occurs the tenth anniversary of the Rent Commencement Date, as defined below, or the Term.

In connection with the signing of the New Lease, the Company entered into a standby letter of credit agreement for $1,500 which serves as a security deposit for the leased office space. This standby letter of credit is secured with restricted cash in a money market account and is included within long-term assets as of June 30, 2024 (refer to Note 6, Restricted Cash).

The annual fixed rent rate under the New Lease is initially $1.3 million (considered by the Company to be at market rate as of the signing of the New Lease), which will commence on November 1, 2024, or the Rent Commencement Date, and will increase 2.5% annually thereafter. The Company expects to begin paying rent in November 2024.

The Company is also responsible for the payment of Additional Rent, as defined in the New Lease, including its share of the operating and tax expenses for the building. As a result, the New Lease contains both a lease (the right to use

the asset) and a non-lease component (common area maintenance services) which are accounted for separately. The Company allocates the consideration to the lease and non-lease component on a relative standalone price basis.

The Company has the option to extend the Term under the New Lease for an additional five years on the same terms and conditions (other than with respect to the annual fixed rent at the annual fair market rental rate, as defined in the New Lease) as set forth in the New Lease. This renewable term is not included as part of the lease term as defined in ASC 842 since it is not reasonably certain that the Company will exercise that option on the Commencement Date.

Since the New Lease does not provide an implicit interest rate, the Company used an incremental borrowing rate equal to the 3-month Secured Overnight Financing Rate, or SOFR, plus 7.75% per annum subject to a 3-month SOFR floor of 2.75%, which is based on the rate that the Company could obtain in the market for a fully collateralized loan equal to the term of the New Lease, or 12.83%.

On July 28, 2023, the Company recorded a lease liability and a right-of-use asset, or the ROU asset, for the New Lease since it obtained control of the premises to begin work on its leasehold improvements prior to the Commencement Date. The initial lease liability of $6,672 was recorded as the sum of the present value of the future minimum lease payments over the term of the lease. Lease incentives of $2,900 were not included within lease payments since the timing of these costs being incurred and reimbursed to the Company was uncertain, and they were neither paid nor payable as of July 28, 2023. These lease incentives reduced the lease liability and ROU asset by the costs incurred once the Company actually incurred the costs and the amounts qualified for reimbursement. The reduction to the lease liability was reversed once the Company was reimbursed for the qualified costs. The reduction to the ROU asset will be recognized prospectively over the remainder of the lease term. The ROU asset of $6,779 was initially recorded as the amount of the lease liability plus prepaid rent paid in May 2023. During the three and six months ended June 2024, the Company was reimbursed $368 and $2,094 of qualified reimbursable lease incentives. As a result, there were no lease incentives remaining to be reimbursed to the Company as of June 30, 2024.

Beginning on July 28, 2023 and during the entire term of the New Lease, interest expense is calculated using the effective interest method and the ROU asset (including prepaid rent) will be amortized on a straight-line basis over the lease term, and both will be recorded as lease expense. As a result, lease expense of $256 and $525 for the New Lease was recorded for the three and six months ended June 30, 2024, consisting of $195 relating to R&D lease expense and $61 relating to G&A lease expense for the three months ended June 30, 2024, and $368 relating to R&D expense and $157 relating to G&A expense for the six months ended June 30, 2024.

Other information related to the leases (both previous and new) was as follows:


	Three Months Ended June 30,						Six Months Ended June 30,
	2024			2023			2024			2023
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash outflows relating to operating leases	$	—		$	496		$	—		$	990
ROU assets obtained in exchange for new operating lease liabilities	$	—		$	—		$	—		$	—
Remaining lease term - operating leases (years)		10.3			0.5			10.3			0.5
Discount rate - operating leases		12.8	%		7.0	%		12.8	%		7.0	%

Future minimum lease payments under non-cancellable operating leases, as well as a reconciliation of these undiscounted cash flows to the operating lease liabilities as of June 30, 2024, were as follows:


Year Ending December 31,
2024 (Excluding the six months ended June 30, 2024)	$	108
2025		1,298
2026		1,330
2027		1,363
2028		1,398
Thereafter		8,874
Total future minimum lease payments, undiscounted		14,371
Less imputed interest		(6,883)
Total	$	7,488

Operating lease liability reported as of June 30, 2024:
Operating lease liability - current	$	168
Operating lease liability - non-current		7,320
Total	$	7,488

Stockholders' Equity - Additional Information (Detail)	3 Months Ended		6 Months Ended		12 Months Ended
Stockholders' Equity - Additional Information (Detail)	Jun. 30, 2024 Vote $ / shares shares	Jun. 30, 2023 shares	Jun. 30, 2024 Vote $ / shares shares	Jun. 30, 2023 shares	Dec. 31, 2023 Vote $ / shares shares	Jun. 07, 2024 shares	Jun. 06, 2024 shares
Sale Of Stock [Line Items]
Common stock, shares authorized	200,000,000		200,000,000		100,000,000	200,000,000	100,000,000
Common stock, par value \| $ / shares	$ 0.001		$ 0.001		$ 0.001
Preferred stock, shares authorized	5,000,000		5,000,000		5,000,000
Preferred stock, par value \| $ / shares	$ 0.001		$ 0.001		$ 0.001
Common stock, shares issued	54,837,764		54,837,764		54,480,704
Common stock, shares outstanding	54,837,764		54,837,764		54,480,704
Preferred stock, shares issued	0		0		0
Preferred stock, shares outstanding	0		0		0
Number of votes for each share of common stock \| Vote	1		1		1
Performance Restricted Stock Units [Member] \| Common Stock
Sale Of Stock [Line Items]
Restricted stock units, vested	0	0	140,500	0
Time-based Restricted Stock Units [Member] \| Common Stock
Sale Of Stock [Line Items]
Restricted stock units, vested	170,685	94,454	216,560	178,247

Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2024

Summary of Assumptions Used in Black-Scholes Option Pricing Model


	Three Months Ended		Six Months Ended
	June 30,		June 30,
	2024	2023	2024	2023
Risk-free interest rate	4.34%	3.38% - 3.89%	4.12% - 4.34%	3.38% - 4.22%
Expected volatility	89.8%	80.3% - 81.3%	89.6% - 89.8%	76.3% - 81.3%
Expected dividend yield	0%	0%	0%	0%
Expected life of employee and Board options (in years)	6.25	6.25	6.25	6.25

Summary of Stock Option Activity


		Weighted
	Number of	Average Exercise
	Shares	Price
Outstanding, December 31, 2023	7,897,647	$	12.99
Granted	3,045,125		0.86
Exercised	—		—
Forfeited	(3,139,154)		4.81
Expired	(1,735,737)		14.15
Outstanding, June 30, 2024	6,067,881	$	10.80
Options exercisable, June 30, 2024	3,797,495

Employees And Non-Employee Members Of Board Of Directors [Member]

Summary of Restricted Stock Unit Activity


		Weighted
	Number of	Average Grant
	Units	Date Fair Value
Outstanding, December 31, 2023	566,324	$	9.27
Awarded	903,883		0.66
Vested and released	(357,060)		7.58
Forfeited	(136,348)		10.57
Outstanding, June 30, 2024	976,799	$	1.74
Restricted stock units exercisable (vested and deferred), June 30, 2024	—

Employee Stock Option [Member]

Summary of Compensation Expense Recognized


	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2024		2023		2024		2023
Research and development	$	275	$	1,447	$	779	$	2,927
General and administrative		1,145		1,434		2,374		2,675
Total stock option expense	$	1,420	$	2,881	$	3,153	$	5,602

Restricted Stock Units [Member]

Summary of Compensation Expense Recognized


	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2024			2023		2024	2023
Research and development	$	(6)	$	116	$	249	$	295
General and administrative		327		445		1,684		898
Total restricted stock unit expense	$	321	$	561	$	1,933	$	1,193

Restricted Cash

6 Months Ended

Jun. 30, 2024

Restricted Cash

Restricted Cash

6. Restricted Cash

In May 2023, the Company entered into a lease agreement with 400 Atlantic Joint Venture LLC and SLJ Atlantic Stamford LLC (tenants-in-common), or the Landlord, for the lease of 26,374 square feet of office space located at 400 Atlantic Street, Stamford, Connecticut 06901 for its new principal executive offices, or the New Lease. The Company is required to maintain a stand-by letter of credit as a security deposit under the New Lease for its office space in Stamford, Connecticut (refer to Note 17, Commitments and Contingencies: Leases). The fair value of the letter of credit approximates its contract value. The Company’s bank requires the Company to maintain a restricted cash balance to serve as collateral for the letter of credit issued to the landlords by the bank. As of June 30, 2024, the restricted cash balance for the New Lease was invested in a commercial money market account.

As of June 30, 2024, the Company had $1,500 of restricted cash related to the New Lease in long-term assets. After the first and second anniversaries of the rent commencement date, the face amount of the letter of credit relating to the New Lease can be reduced by $500 each period if the Company is not in default of its lease obligations. As of December

31, 2023, the Company had $408 of restricted cash related to its previous lease (which was terminated in December 2023 and became unrestricted in January 2024) in current assets and $1,500 of restricted cash related to the New Lease in long-term assets.

The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the Condensed Consolidated Balance Sheets that sum to the total of the same such amounts shown in the Condensed Consolidated Statements of Cash Flows.


	June 30, 2024		December 31, 2023
Cash and cash equivalents	$	49,239	$	51,775
Restricted cash, current assets		—		408
Restricted cash, long-term assets		1,500		1,500
Total cash, cash equivalents, and restricted cash shown in the Condensed Consolidated Statements of Cash Flows	$	50,739	$	53,683

Revenue Recognition (Tables)

6 Months Ended

Jun. 30, 2024

Revenue Recognition

Schedule of disaggregation of revenue


	Three Months Ended June 30,				Six Months Ended June 30,
	2024		2023			2024	2023
Collaborative revenue
CSL Vifor (KORSUVA injection profit sharing)	$	—	$	5,410	$	788	$	8,160
Total collaborative revenue	$	—	$	5,410	$	788	$	8,160
Commercial supply revenue
CSL Vifor (KORSUVA injection)	$	—	$	1,400	$	640	$	4,591
Total commercial supply revenue	$	—	$	1,400	$	640	$	4,591
Royalty revenue
CSL Vifor (Kapruvia ex-U.S.)	$	—	$	123	$	—	$	248
Total royalty revenue	$	—	$	123	$	—	$	248
Clinical compound revenue
Maruishi	$	—	$	—	$	84	$	99
Total clinical compound revenue	$	—	$	—	$	84	$	99
Other revenue (non-cash)
CSL Vifor (Kapruvia ex-U.S.)	$	359	$	—	$	649	$	—
Maruishi		632		—		965		—
Total other revenue	$	991	$	—	$	1,614	$	—

Commitments and Contingencies - Restructuring activity (Detail) - USD ($) $ in Thousands		1 Months Ended	3 Months Ended
	Jun. 14, 2024	Jan. 31, 2024	Jun. 30, 2024	Mar. 31, 2024
Commitments and Contingencies
Restructuring and related cost, percentage of workforce reduction	70.00%	50.00%
Total expense recorded in the three months ended for the period			$ 2,581	$ 2,401
Payments made in the three months ended for the period			(301)	(1,702)
Remaining amounts to be paid as of period			$ 2,979	$ 699

Royalty Purchase and Sale Agreement (Tables)

6 Months Ended

Jun. 30, 2024

Royalty Purchase and Sale Agreement

Schedule of activity of the HCR agreement

The following table summarizes the activity of the HCR Agreement (in thousands):


Royalty purchase and sale agreement balance at December 31, 2023	$	37,079
Payments		(1,295)
Non-cash interest expense		3,892
Balance at June 30, 2024	$	39,676

Effective interest rate		20.95	%

Fair Value Measurements - Additional Information (Detail) - Significant Unobservable Inputs (Level 3) [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Purchases of financial assets	$ 0	$ 0	$ 0	$ 0
Sales of financial assets	0	0	0	0
Maturities of financial assets	0	0	0	0
Unrealized gains	0	0	0	0
Unrealized losses	0	0	0	0
Transfer of financial assets into or out of level 3 of fair value	$ 0	$ 0	$ 0	$ 0

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Jun. 30, 2024	Jun. 07, 2024	Jun. 06, 2024	Dec. 31, 2023
CONDENSED CONSOLIDATED BALANCE SHEETS
Preferred stock, par value	$ 0.001			$ 0.001
Preferred stock, shares authorized	5,000,000			5,000,000
Preferred stock, shares issued	0			0
Preferred stock, shares outstanding	0			0
Common stock, par value	$ 0.001			$ 0.001
Common stock, shares authorized	200,000,000	200,000,000	100,000,000	100,000,000
Common stock, shares issued	54,837,764			54,480,704
Common stock, shares outstanding	54,837,764			54,480,704

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Loss	Total
Balance, Value at Dec. 31, 2022	$ 53	$ 726,630	$ (566,232)	$ (1,672)	$ 158,779
Balance, Shares at Dec. 31, 2022	53,797,341
Stock-based compensation expense		2,972			2,972
Shares issued upon exercise of stock options, value	$ 1	559			560
Shares issued upon exercise of stock options, shares	93,218
Shares issued upon vesting of restricted stock units, value		381			381
Shares issued upon vesting of restricted stock units, shares	83,793
Net loss			(26,665)		(26,665)
Other comprehensive income				571	571
Balance, Value at Mar. 31, 2023	$ 54	730,542	(592,897)	(1,101)	136,598
Balance, Shares at Mar. 31, 2023	53,974,352
Balance, Value at Dec. 31, 2022	$ 53	726,630	(566,232)	(1,672)	158,779
Balance, Shares at Dec. 31, 2022	53,797,341
Net loss					(58,144)
Other comprehensive income				942
Balance, Value at Jun. 30, 2023	$ 54	733,984	(624,376)	(730)	108,932
Balance, Shares at Jun. 30, 2023	54,068,806
Balance, Value at Mar. 31, 2023	$ 54	730,542	(592,897)	(1,101)	136,598
Balance, Shares at Mar. 31, 2023	53,974,352
Stock-based compensation expense		3,116			3,116
Shares issued upon vesting of restricted stock units, value		326			326
Shares issued upon vesting of restricted stock units, shares	94,454
Net loss			(31,479)		(31,479)
Other comprehensive income				371	371
Balance, Value at Jun. 30, 2023	$ 54	733,984	(624,376)	(730)	108,932
Balance, Shares at Jun. 30, 2023	54,068,806
Balance, Value at Dec. 31, 2023	$ 54	742,036	(684,745)	(260)	57,085
Balance, Shares at Dec. 31, 2023	54,480,704
Stock-based compensation expense		1,660			1,660
Shares issued upon vesting of restricted stock units, value		1,685			1,685
Shares issued upon vesting of restricted stock units, shares	186,375
Net loss			(30,696)		(30,696)
Other comprehensive income				69	69
Balance, Value at Mar. 31, 2024	$ 54	745,381	(715,441)	(191)	29,803
Balance, Shares at Mar. 31, 2024	54,667,079
Balance, Value at Dec. 31, 2023	$ 54	742,036	(684,745)	(260)	57,085
Balance, Shares at Dec. 31, 2023	54,480,704
Net loss					(50,712)
Other comprehensive income				139
Balance, Value at Jun. 30, 2024	$ 54	747,122	(735,457)	(121)	11,598
Balance, Shares at Jun. 30, 2024	54,837,764
Balance, Value at Mar. 31, 2024	$ 54	745,381	(715,441)	(191)	29,803
Balance, Shares at Mar. 31, 2024	54,667,079
Stock-based compensation expense		1,507			1,507
Shares issued upon vesting of restricted stock units, value		234			234
Shares issued upon vesting of restricted stock units, shares	170,685
Net loss			(20,016)		(20,016)
Other comprehensive income				70	70
Balance, Value at Jun. 30, 2024	$ 54	$ 747,122	$ (735,457)	$ (121)	$ 11,598
Balance, Shares at Jun. 30, 2024	54,837,764

- Definition

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

+ References

+ Details

- Definition

Amount after tax and reclassification adjustments of other comprehensive income (loss).

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

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+ Details

Accumulated Other Comprehensive Loss

6 Months Ended

Jun. 30, 2024

Accumulated Other Comprehensive Loss

Accumulated Other Comprehensive Loss

4. Accumulated Other Comprehensive Loss

The following table summarizes the changes in accumulated other comprehensive loss, net of tax, from unrealized gains on available-for-sale marketable securities, the Company’s only component of accumulated other comprehensive loss, for the six months ended June 30, 2024 and 2023, respectively.


	Total Accumulated
	Other Comprehensive
	Loss
Balance, December 31, 2023	$	(260)
Other comprehensive income before reclassifications		139
Amount reclassified from accumulated other comprehensive loss		—
Net current period other comprehensive income		139
Balance, June 30, 2024	$	(121)

Balance, December 31, 2022	$	(1,672)
Other comprehensive income before reclassifications		942
Amount reclassified from accumulated other comprehensive loss		—
Net current period other comprehensive income		942
Balance, June 30, 2023	$	(730)

Amounts reclassified out of accumulated other comprehensive loss into net loss are determined by specific identification. There were no reclassifications out of accumulated other comprehensive loss and into net loss for each of the three and six months ended June 30, 2024 and 2023.

Related Party Transactions

6 Months Ended

Jun. 30, 2024

Related Party Transactions

Related Party Transactions

18. Related Party Transactions

As of June 30, 2024, Vifor International owned 7,396,770, or 13.5%, of the Company’s common stock. CSL Vifor and its affiliates are considered related parties as of June 30, 2024 and December 31, 2023 (see Note 12, Collaboration and Licensing Agreements).

As of June 30, 2024 and December 31, 2023, amounts due from CSL Vifor of $359 and $2,765, respectively, primarily relating to royalty payments from CSL Vifor in the current period and the Company’s share of the profit generated by sales of KORSUVA injection in the United States by CSL Vifor, its commercial supply of KORSUVA injection to CSL Vifor, and royalty payments from CSL Vifor in the prior period were included within accounts receivable, net – related party.

The Company’s collaborative revenue of $788 and $8,160 from its share of the profit generated by sales of KORSUVA injection in the United States by CSL Vifor was included within collaborative revenue for the six months ended June 30, 2024 and 2023, respectively. The Company’s collaborative revenue of $5,410 from its share of the profit generated by sales of KORSUVA injection in the United States by CSL Vifor was included within collaborative revenue for the three months ended June 30, 2023. The Company also recorded a liability in accrued professional fees and other within accounts payable and accrued expenses for $1,447 and a corresponding expense in other G&A expense as a result of the negative profit share amount in the second quarter of 2024.

Sales of KORSUVA injection to CSL Vifor of $640 and $4,591 were included within commercial supply revenue for the six months ended June 30, 2024 and 2023, respectively. Sales of KORSUVA injection to CSL Vifor of $1,400 were included within commercial supply revenue for the three months ended June 30, 2023.

The Company recorded $123 and $248 as royalty revenue based on net sales of Kapruvia outside of the United States during the three and six months ended June 30, 2023, respectively. There was no royalty revenue recorded during the three and six months ended June 30, 2024.

The Company recorded $359 and $649 as other revenue from its royalty payments from CSL Vifor for the three and six months ended June 30, 2024, respectively. There was no other revenue recorded for the three and six months ended June 30, 2023.

- Definition

The entire disclosure for related party transactions. Examples of related party transactions include transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners; and (d) affiliates.

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-URI https://asc.fasb.org//1943274/2147483326/850-10-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(2)(g)(3))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-1

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(2)(c))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(2)(e))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-1

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//850/tableOfContent

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483326/850-10-50-6

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483326/850-10-50-1

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483326/850-10-50-1

+ Details

Inventory, net (Tables)

6 Months Ended

Jun. 30, 2024

Inventory, net

Schedule of Inventory, net

Inventory, net consists of the following:


	June 30, 2024		December 31, 2023
Raw materials	$	2,124	$	2,639
Work-in-process		1,009		708
		3,133		3,347
Less Inventory Reserve for Obsolescence		(1,489)		(526)
Total	$	1,644	$	2,821

Available-for-Sale Marketable Securities - Schedule of Fair Values and Continuous Unrealized Loss Positions of Available-for-Sale Marketable Securities (Detail) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale marketable securities, continuous unrealized loss position, 12 Months or Greater, Fair Value	$ 7,379	$ 9,238
Available-for-sale marketable securities, continuous unrealized loss position, 12 Months or Greater, Gross Unrealized Losses	(121)	(263)
Available-for-sale marketable securities, continuous unrealized loss position, Fair Value	7,379	9,238
Available-for-sale marketable securities, continuous unrealized loss position, Gross Unrealized Losses	(121)	(263)
U.S. Government Agency Obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale marketable securities, continuous unrealized loss position, 12 Months or Greater, Fair Value	7,379	7,238
Available-for-sale marketable securities, continuous unrealized loss position, 12 Months or Greater, Gross Unrealized Losses	(121)	(262)
Available-for-sale marketable securities, continuous unrealized loss position, Fair Value	7,379	7,238
Available-for-sale marketable securities, continuous unrealized loss position, Gross Unrealized Losses	$ (121)	(262)
Corporate Bonds [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale marketable securities, continuous unrealized loss position, 12 Months or Greater, Fair Value		2,000
Available-for-sale marketable securities, continuous unrealized loss position, 12 Months or Greater, Gross Unrealized Losses		(1)
Available-for-sale marketable securities, continuous unrealized loss position, Fair Value		2,000
Available-for-sale marketable securities, continuous unrealized loss position, Gross Unrealized Losses		$ (1)

- 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

Prepaid expenses

6 Months Ended

Jun. 30, 2024

Prepaid expenses

Prepaid expenses

8. Prepaid expenses

As of June 30, 2024, prepaid expenses were $3,777, consisting of $2,458 of prepaid R&D clinical costs, $1,021 of prepaid insurance and $298 of other prepaid costs. As of December 31, 2023, prepaid expenses were $8,154, consisting of $7,245 of prepaid R&D clinical costs, $492 of prepaid insurance, and $417 of other prepaid costs.

Collaboration and Licensing Agreements - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended			3 Months Ended		6 Months Ended
	May 31, 2022	Oct. 31, 2020	May 31, 2018	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	May 17, 2018
Collaboration and Licensing Agreements:
Revenue from contract with customer				$ 991	$ 6,933	$ 3,126	$ 13,098
Vifor Fresenius Medical Care Renal Pharma Ltd Agreement No 2
Collaboration and Licensing Agreements:
Percentage of net profit sharing			50.00%
CSL Vifor Maximum \| Vifor Fresenius Medical Care Renal Pharma Ltd Agreement No 1
Collaboration and Licensing Agreements:
Potential sales-based milestone payments		$ 240,000
CSL Vifor \| Vifor Fresenius Medical Care Renal Pharma Ltd Agreement No 1
Collaboration and Licensing Agreements:
Percentage of net profit sharing	40.00%
Affiliated Entity \| CSL Vifor \| Vifor Fresenius Medical Care Renal Pharma Ltd Agreement No 1
Collaboration and Licensing Agreements:
Percentage of net profit sharing	60.00%
Affiliated Entity \| Vifor Fresenius Medical Care Renal Pharma Ltd. \| Maximum \| Regulatory and Commercial Milestones [Member]
Collaboration and Licensing Agreements:
Potential milestone payments								$ 440,000

Net Loss per Share

6 Months Ended

Jun. 30, 2024

Net Loss Per Share

Net Loss Per Share

14. Net Loss Per Share

The Company computes basic net loss per share by dividing net loss by the weighted-average number of shares of common stock outstanding. Diluted net loss per share includes the potential dilutive effect of common stock equivalents as if such securities were exercised during the period, when the effect is dilutive. Common stock equivalents may include outstanding stock options or restricted stock units, which are included using the treasury stock method when dilutive. For each of the three and six months ended June 30, 2024 and 2023, the Company excluded the effects of potentially dilutive shares that were outstanding during those respective periods from the denominator as their inclusion would be anti-dilutive due to the Company’s net losses during those periods.

The denominators used in the net loss per share computations are as follows:


	Three Months Ended		Six Months Ended
	June 30,		June 30,
	2024	2023	2024	2023
Basic:
Weighted average common shares outstanding	54,724,692	54,002,988	54,656,391	53,937,875
Diluted:
Weighted average common shares outstanding - Basic	54,724,692	54,002,988	54,656,391	53,937,875
Common stock equivalents*	—	—	—	—
Denominator for diluted net loss per share	54,724,692	54,002,988	54,656,391	53,937,875

*	No amounts were considered as their effects would be anti-dilutive.

Basic and diluted net loss per share are computed as follows:


	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2024		2023		2024		2023
Net loss - basic and diluted	$	(20,016)	$	(31,479)	$	(50,712)	$	(58,144)
Weighted-average common shares outstanding:
Basic and diluted		54,724,692		54,002,988		54,656,391		53,937,875
Net loss per share, basic and diluted:	$	(0.37)	$	(0.58)	$	(0.93)	$	(1.08)

As of June 30, 2024, 6,067,881 stock options and 976,799 restricted stock units were outstanding, which could potentially dilute basic earnings per share in the future, but were not included in the computation of diluted net loss per share because to do so would have been anti-dilutive as a result of the net loss for the period.

As of June 30, 2023, 8,134,597 stock options and 791,853 restricted stock units were outstanding, which could potentially dilute basic earnings per share in the future, but were not included in the computation of diluted net loss per share because to do so would have been anti-dilutive as a result of the net loss for the period.

Inventory, net - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2024
Inventory, net
Inventory write-down	$ 1,489	$ 1,489

Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2024

Fair Value Measurements

Summary of Financial Assets Measured at Fair Value on Recurring Basis

Fair value measurement as of June 30, 2024:


			Quoted prices in		Significant other		Significant
Financial assets			active markets for		observable		unobservable
			identical assets		inputs		inputs
Type of Instrument	Total		(Level 1)		(Level 2)		(Level 3)
Cash and cash equivalents:
Money market funds and checking accounts	$	49,239	$	49,239	$	—	$	—
Available-for-sale marketable securities:
U.S. government agency obligations		7,379		—		7,379		—
Restricted cash:
Commercial money market account		1,500		1,500		—		—
Total financial assets	$	58,118	$	50,739	$	7,379	$	—

Fair value measurement as of December 31, 2023:


			Quoted prices in		Significant other		Significant
Financial assets			active markets for		observable		unobservable
			identical assets		inputs		inputs
Type of Instrument	Total		(Level 1)		(Level 2)		(Level 3)
Cash and cash equivalents:
Money market funds and checking accounts	$	51,775	$	51,775	$	—	$	—
Available-for-sale marketable securities:
U.S. Treasury securities		37,246		—		37,246		—
U.S. government agency obligations		7,238		—		7,238		—
Corporate bonds		4,499		—		4,499		—
Restricted cash:
Commercial money market account		1,908		1,908		—		—
Total financial assets	$	102,666	$	53,683	$	48,983	$	—

Available-for-Sale Marketable Securities - Schedule of Amortized Cost and Fair Values of Marketable Debt Securities by Contractual Maturity (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Debt Securities [Abstract]
Amortized Cost of marketable debt securities, contractual maturity, less than one year	$ 7,500		$ 7,500		$ 49,243
Amortized cost	7,500		7,500		49,243
Fair value of marketable debt securities, contractual maturities, less than one year	7,379		7,379		48,983
Total fair Value of marketable debt securities, contractual maturity	7,379		7,379		48,983
Proceeds from sale of available-for-sale marketable securities	0	$ 0	0	$ 0
Interest receivable	$ 119		$ 119		$ 139

Available-for-Sale Marketable Securities (Tables)

6 Months Ended

Jun. 30, 2024

Available-for-Sale Marketable Securities

Summary of Available-for-Sale Marketable Securities by Major Type of Security

As of June 30, 2024


			Gross Unrealized				Estimated Fair
Type of Security	Amortized Cost		Gains		Losses		Value
U.S. government agency obligations	$	7,500	$	—	$	(121)	$	7,379
Total available-for-sale marketable securities	$	7,500	$	—	$	(121)	$	7,379

As of December 31, 2023


			Gross Unrealized				Estimated Fair
Type of Security	Amortized Cost		Gains		Losses		Value
U.S. Treasury securities	$	37,243	$	3	$	—	$	37,246
U.S. government agency obligations		7,500		—		(262)		7,238
Corporate bonds		4,500		—		(1)		4,499
Total available-for-sale marketable securities	$	49,243	$	3	$	(263)	$	48,983

Schedule of Fair Values and Continuous Unrealized Loss Positions of Available-for-Sale Marketable Securities

As of June 30, 2024


	Less than 12 Months				12 Months or Greater				Total
			Gross				Gross				Gross
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
	Value		Losses		Value		Losses		Value		Losses
U.S. government agency obligations	$	—	$	—	$	7,379	$	(121)	$	7,379	$	(121)
Total	$	—	$	—	$	7,379	$	(121)	$	7,379	$	(121)

As of December 31, 2023


	Less than 12 Months				12 Months or Greater				Total
			Gross				Gross				Gross
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
	Value		Losses		Value		Losses		Value		Losses
U.S. government agency obligations	$	—	$	—	$	7,238	$	(262)	$	7,238	$	(262)
Corporate bonds		—		—		2,000		(1)		2,000		(1)
Total	$	—	$	—	$	9,238	$	(263)	$	9,238	$	(263)

Schedule of Amortized Cost and Fair Values of Marketable Debt Securities by Contractual Maturity


	As of June 30, 2024				As of December 31, 2023
Contractual maturity	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Less than one year	$	7,500	$	7,379	$	49,243	$	48,983
More than one year		—		—		—		—
Total	$	7,500	$	7,379	$	49,243	$	48,983

Business

6 Months Ended

Jun. 30, 2024

Business.

Business

1. Business

Cara Therapeutics, Inc., or the Company, is a biopharmaceutical corporation formed on July 2, 2004. The Company has been focused on leading a new treatment paradigm to improve the lives of patients suffering from chronic pruritus. The Company’s primary activities to date have been organizing and staffing the Company, developing its lead product and product candidates, including conducting preclinical studies and clinical trials of difelikefalin-based product candidates, and raising capital.

On June 14, 2024, the Board of Directors of the Company approved a streamlined operating plan exploring strategic alternatives focused on maximizing shareholder value after the Company announced its decision to discontinue the clinical program in notalgia paresthetica, or NP, on June 12, 2024. The Company’s decision to discontinue the clinical program in NP followed the outcome from the dose-finding Part A of the KOURAGE-1 study evaluating the efficacy and safety of oral difelikefalin for moderate-to-severe pruritus in adult patients with NP in which oral difelikefalin did not demonstrate a meaningful clinical benefit at any dose compared to placebo. The Company’s decision was not related to any safety or medical issues, or negative regulatory feedback related to the Company’s NP program. In connection with the streamlined operating plan, the Board of Directors also approved a second reduction in the Company’s workforce by approximately 70%, which the Company substantially completed by June 30, 2024 (see Note 17, Commitments and Contingencies – Restructuring Actions).

In August 2021, the Company received U.S. Food and Drug Administration, or FDA, approval for KORSUVA®(difelikefalin) injection, or KORSUVA injection, for the treatment of moderate-to-severe pruritus associated with chronic kidney disease in adults undergoing hemodialysis. Commercial launch of KORSUVA injection began in the United States in April 2022 and the Company began recording the associated profit-sharing revenues in the second quarter of 2022.

In April 2022, the European Commission granted marketing authorization to difelikefalin injection under the brand name Kapruvia® (difelikefalin), or Kapruvia, for the treatment of moderate-to-severe pruritus associated with chronic kidney disease in adult hemodialysis patients. The marketing authorization approved Kapruvia for use in all member states of the European Union, or EU, as well as Iceland, Liechtenstein, and Norway. Kapruvia was also approved in the United Kingdom in April 2022. Commercial launches in Austria, Germany, Sweden, France, the Netherlands, Finland, and Norway have commenced. In August 2022, as part of the Access Consortium, difelikefalin injection was approved in Switzerland under the brand name Kapruvia, as well as Singapore and Canada under the brand name KORSUVA. Commercial launch in Switzerland has also commenced. In November 2022, difelikefalin injection was approved in the last Access Consortium country, Australia, under the brand name KORSUVA. Difelikefalin injection was also approved in the United Arab Emirates, Kuwait, Israel, Japan, and Saudi Arabia under the brand name KORSUVA in January 2023, May 2023, June 2023, September 2023, and January 2024, respectively. The Company expects additional approvals and commercial launches over the next 12-18 months. On November 1, 2023, the Company entered into a Purchase and Sale Agreement, or the HCR Agreement, with HCRX Investments Holdco, L.P. and Healthcare Royalty Partners IV, L.P., or collectively HCR, pursuant to which HCR will receive current and future royalty and milestone payments for Kapruvia and KORSUVA (ex U.S. only) up to certain capped amounts in exchange for certain payments made to the Company (see Note 10, Royalty Purchase and Sale Agreement).

In 2018, the Company entered into a license and collaboration agreement with a joint venture between Vifor Pharma Group and Fresenius Medical Care Renal Pharmaceutical Ltd., or Vifor Fresenius Medical Care Renal Pharma Ltd., that provides full commercialization rights of Kapruvia, and where applicable KORSUVA, to Vifor Fresenius Medical Care Renal Pharma Ltd. worldwide (excluding the United States, Japan and South Korea). In 2020, the Company entered into a second licensing and collaboration agreement, along with stock purchase agreements, with Vifor (International) Ltd., or Vifor International, that provides full commercialization rights of KORSUVA injection to Vifor International in

dialysis clinics in the United States under a profit-sharing arrangement (see Note 12, Collaboration and Licensing Agreements).

In May 2022, Vifor International assigned its rights and obligations under the license agreement and a supply agreement, as permitted under the agreements, to Vifor Fresenius Medical Care Renal Pharma Ltd. The Company’s rights and obligations under these agreements were unaffected by this assignment and the assignment did not affect the Company’s economic rights under the agreements with Vifor International.

In August 2022, Vifor Pharma Group (which includes Vifor International) was acquired by CSL Limited and subsequently renamed CSL Vifor as part of the acquisition. The acquisition of Vifor Pharma Group did not affect any of the Company’s rights and obligations pursuant to these agreements.

The Company also has a license agreement with Maruishi Pharmaceutical Co. Ltd., or Maruishi, under which the Company granted Maruishi an exclusive license to develop, manufacture, and commercialize drug products containing difelikefalin for acute pain and/or uremic pruritus in Japan. In September 2023, Maruishi received manufacturing and marketing approval from Japan’s Ministry of Health, Labour and Welfare for KORSUVA IV Injection Syringe for the treatment of pruritus in hemodialysis patients (see Note 12, Collaboration and Licensing Agreements). In the fourth quarter of 2023, the Company entered into the HCR Agreement pursuant to which HCR will receive current and future royalty and milestone payments for KORSUVA (Japan) up to certain capped amounts in exchange for certain payments to the Company (see Note 10, Royalty Purchase and Sale Agreement).

As of June 30, 2024, the Company has raised aggregate net proceeds of approximately $520,700 from several rounds of equity financing, including its initial public offering, or IPO, which closed in February 2014 and four follow-on public offerings of common stock, which closed in July 2019, July 2018, April 2017 and August 2015, respectively, the issuance of common stock pursuant to its open market sales agreement with Jefferies LLC as sales agent in 2023, and the issuance of convertible preferred stock and debt prior to the IPO. The Company has also earned approximately $288,600 under its license and supply agreements for difelikefalin, primarily with CSL Vifor, Maruishi, and Chong Kun Dang Pharmaceutical Corp., or CKDP, and an earlier product candidate for which development efforts ceased in 2007. Under the terms of the HCR Agreement, the Company received net proceeds of $36,474 for the sale of future ex-U.S. royalties and milestones under Vifor Agreement No. 2 (as defined below) and the Maruishi Agreement in November and December 2023. The Company has also received aggregate net proceeds of approximately $98,000 from the issuance and sale of the Company’s common stock to Vifor International in connection with the Company’s license agreement with CSL Vifor (see Note 12, Collaboration and Licensing Agreements).

As of June 30, 2024, the Company had unrestricted cash and cash equivalents and marketable securities of $56,618 and an accumulated deficit of $735,457. The Company has incurred substantial net losses and negative cash flows from operating activities in nearly every fiscal period since inception and expects this trend to continue for the foreseeable future. The Company recognized net losses of $20,016 and $31,479 for the three months ended June 30, 2024 and 2023, respectively, and $50,712 and $58,144 for the six months ended June 30, 2024 and 2023, respectively, and had net cash used in operating activities of $42,890 and $55,063 for the six months ended June 30, 2024 and 2023, respectively.

The Company is subject to risks and uncertainties including, should it resume development of its product candidate or future product candidates, risks and uncertainties common to other life science companies including, but not limited to, uncertainty of product development and commercialization, lack of marketing and sales history, development by its competitors of new technological innovations, dependence on key personnel, market acceptance of products, product liability, protection of proprietary technology, ability to raise additional financing, and compliance with FDA and other government regulations. Should the Company resume development of its product candidate or any future product

candidate, even if the Company’s development efforts are successful, it is uncertain when, if ever, the Company would generate additional recurring product revenue or achieve profitability.

Accounts Payable and Accrued Expenses (Tables)

6 Months Ended

Jun. 30, 2024

Accounts Payable and Accrued Expenses

Schedule of Accounts Payable and Accrued Expenses

Accounts payable and accrued expenses consist of the following:


	June 30, 2024		December 31, 2023
Accounts payable	$	6,755	$	11,583
Accrued research projects		1,010		4,343
Accrued compensation and benefits		1,214		6,519
Accrued professional fees and other		4,754		3,147
Total	$	13,733	$	25,592

Royalty Purchase and Sale Agreement

6 Months Ended

Jun. 30, 2024

Royalty Purchase and Sale Agreement

Royalty Purchase and Sale Agreement

10. Royalty Purchase and Sale Agreement

During the fourth quarter of 2023, the Company, through its wholly-owned subsidiary Cara Royalty Sub, entered into the HCR Agreement with HCR, pursuant to which Cara Royalty Sub sold, or agreed to sell, to HCR certain of its rights to receive royalty payments, or the Royalties, due and payable to Cara Royalty Sub (as assignee of the Company) under the Maruishi Agreement and Vifor Agreement No. 2. (as defined below), collectively the Covered License Agreements, in exchange for up to $40,000. The Company has retained all of its rights, title and interest in, to and under the Covered License Agreements that relate to any non-intravenous formulation of difelikefalin.

Under the terms of the HCR Agreement, Cara Royalty Sub received an upfront payment of $16,915 in November 2023, representing the $17,500 to which the Company was initially entitled, net of advisory fees and certain of HCR’s transaction-related expenses which the Company agreed to reimburse. In December 2023, Cara Royalty Sub received an additional payment of $19,770, representing the $20,000 milestone it achieved for Kapruvia (difelikefalin) pricing in Germany being approved above a certain threshold amount per dose, net of advisory fees. There were additional issuance costs of $211 related to the HCR Agreement resulting in aggregate net proceeds of $36,474. An additional $2,500 milestone payment is due to Cara Royalty Sub upon achievement of a 2024 sales milestone of KORSUVA in Japan.

The HCR Agreement will automatically expire, and the payment of Royalties to HCR will cease, when HCR has received payments of Royalties equal to two times the aggregate amount of payments made by HCR under the HCR Agreement if achieved on or prior to December 31, 2029, or 2.8 times the aggregate amount of payments made by HCR under the HCR Agreement, if not achieved on or prior to December 31, 2029. After the HCR Agreement expires, all rights to receive the Royalties return to Cara Royalty Sub.

Issuance costs pursuant to the HCR Agreement consisting primarily of advisory and legal fees totaled $1,025 including the amount of HCR’s transaction-related expenses that the Company reimbursed. The effective interest rate includes cash flow projections for future royalty and milestone payments, which are sensitive to certain assumptions, including market size, market penetration and sales price, that are forward looking and could be affected by future market conditions. During the three and six months ended June 30, 2024, $610 and $1,295, respectively, were repaid to HCR under the HCR Agreement.

The following table summarizes the activity of the HCR Agreement (in thousands):


Royalty purchase and sale agreement balance at December 31, 2023	$	37,079
Payments		(1,295)
Non-cash interest expense		3,892
Balance at June 30, 2024	$	39,676

Effective interest rate		20.95	%

Stock-Based Compensation - Restricted Stock Unit Compensation Expense (Detail) - Restricted Stock Units [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Compensation expense	$ 321	$ 561	$ 1,933	$ 1,193
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Compensation expense	(6)	116	249	295
General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Compensation expense	$ 327	$ 445	$ 1,684	$ 898

Revenue Recognition - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Collaboration Arrangement [Line Items]
Accounts receivable, net - related party	$ 359		$ 359		$ 2,765
Total revenue	991	$ 6,933	3,126	$ 13,098
Accrued professional fees and other	4,754		4,754		3,147
Other receivables	764		764		555
Commercial supply revenue
Collaboration Arrangement [Line Items]
Total revenue		1,400	640	4,591
Royalty revenue
Collaboration Arrangement [Line Items]
Total revenue		123		248
Collaborative revenue
Collaboration Arrangement [Line Items]
Total revenue		5,410	788	8,160
Clinical compound revenue
Collaboration Arrangement [Line Items]
Total revenue			84	99
Other revenue (non-cash)
Collaboration Arrangement [Line Items]
Total revenue	991	0	1,614	0
CSL Vifor, Maruishi and CKDP Agreements [Member]
Collaboration Arrangement [Line Items]
Other contract Assets	0		0		0
Other contract liabilities	0		0		0
Maruishi Agreement [Member]
Collaboration Arrangement [Line Items]
Other receivables	645		645		415
Maruishi Agreement [Member] \| Clinical compound revenue
Collaboration Arrangement [Line Items]
Total revenue	0	0	84	99
Maruishi Agreement [Member] \| Other revenue (non-cash)
Collaboration Arrangement [Line Items]
Total revenue	632		965
Affiliated Entity [Member] \| CSL Vifor
Collaboration Arrangement [Line Items]
Accounts receivable, net - related party	359		359		$ 2,765
Affiliated Entity [Member] \| CSL Vifor \| CSL Vifor Profit Sharing
Collaboration Arrangement [Line Items]
Negative profit share for the Company	1,447
Affiliated Entity [Member] \| CSL Vifor \| CSL Vifor Profit Sharing \| Collaborative revenue
Collaboration Arrangement [Line Items]
Total revenue		5,410	788	8,160
Accrued professional fees and other	1,447		1,447
Affiliated Entity [Member] \| CSL Vifor \| CSL Vifor Korsuva [Member]
Collaboration Arrangement [Line Items]
Net sales	(2,664)	11,467	(858)	17,141
Affiliated Entity [Member] \| CSL Vifor \| CSL Vifor Korsuva [Member] \| Commercial supply revenue
Collaboration Arrangement [Line Items]
Total revenue	0	1,400	640	4,591
Affiliated Entity [Member] \| CSL Vifor \| CSL Vifor Korsuva [Member] \| Commercial Supply Revenue With Associated Costs Of Goods Sold [Member]
Collaboration Arrangement [Line Items]
Cost of goods sold		1,418	620	4,008
Affiliated Entity [Member] \| CSL Vifor \| CSL Vifor Kapruvia [Member] \| Royalty revenue
Collaboration Arrangement [Line Items]
Total revenue	0	$ 123	0	$ 248
Affiliated Entity [Member] \| CSL Vifor \| CSL Vifor Kapruvia [Member] \| Other revenue (non-cash)
Collaboration Arrangement [Line Items]
Total revenue	$ 359		$ 649

Restricted Cash - Additional Information (Detail) $ in Thousands	Jun. 30, 2024 USD ($)	Dec. 31, 2023 USD ($)	May 31, 2023 ft²
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash, current assets		$ 408
Restricted cash, long-term assets	$ 1,500	1,500
Old Stamford Lease [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted cash, current assets		408
New Stamford Lease [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Lease for office space area (square feet) \| ft²			26,374
Restricted cash, long-term assets	1,500	$ 1,500
Letters of credit, face amount that can be reduced	$ 500

Business - Additional Information (Detail) $ in Thousands		1 Months Ended	3 Months Ended					6 Months Ended
Business - Additional Information (Detail) $ in Thousands	Jun. 14, 2024	Jan. 31, 2024	Jun. 30, 2024 USD ($) item	Mar. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Jun. 30, 2023 USD ($)	Mar. 31, 2023 USD ($)	Jun. 30, 2024 USD ($) item	Jun. 30, 2023 USD ($)
Nature Of Business [Line Items]
Date of formation								Jul. 02, 2004
Restructuring and related cost, percentage of workforce reduction	70.00%	50.00%
Proceeds from equity and debt financing			$ 520,700					$ 520,700
Number of follow-on public offerings \| item			4					4
Unrestricted cash and cash equivalents and marketable securities			$ 56,618					$ 56,618
Accumulated deficit			735,457		$ 684,745			735,457
Net loss			(20,016)	$ (30,696)		$ (31,479)	$ (26,665)	(50,712)	$ (58,144)
Net cash used in operating activities								$ (42,890)	$ (55,063)
HCR Agreement [Member]
Nature Of Business [Line Items]
Net proceeds from the royalty purchase and sale agreement					$ 36,474
Minimum [Member]
Nature Of Business [Line Items]
Expected approvals and commercial launches period								12 months
Maximum [Member]
Nature Of Business [Line Items]
Expected approvals and commercial launches period								18 months
CSL Vifor, Maruishi and CKDP \| License and supply agreements for difelikefalin
Nature Of Business [Line Items]
Payments received in connection with license and supply agreements			$ 288,600					$ 288,600
Affiliated Entity [Member] \| Vifor International Ltd.
Nature Of Business [Line Items]
Proceeds from the sale of common stock under license agreement with Vifor International								$ 98,000

Basis of Presentation (Policies)	6 Months Ended
Basis of Presentation (Policies)	Jun. 30, 2024
Business.
Use of Estimates	Use of Estimates The preparation of condensed consolidated financial statements in conformity with GAAP requires the Company to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities, as of the date of the condensed consolidated financial statements as well as the reported amounts of revenues and expenses during the reporting period. The more significant estimates include the fair value of marketable securities that are classified as Level 2 of the fair value hierarchy, the amount and periods over which certain revenues will be recognized, including licensing and collaborative revenue recognized from non-refundable up-front and milestone payments and future ex-U.S. royalties and milestones projected in relation to the HCR Agreement, related party accounts receivable reserve, as applicable, inventory valuation and related reserves, research and development, or R&D, clinical costs and accrued research projects included in prepaid expenses and accounts payable and accrued expenses, the amount of non-cash compensation costs related to share-based payments to employees and non-employees, restructuring costs, the amount of lease incentives, as applicable, and the incremental borrowing rate used in lease calculations, and the likelihood of realization of deferred tax assets. The impact from global economic conditions and potential and continuing disruptions to and volatility in the credit and equity markets in the United States and worldwide are highly uncertain and cannot be predicted, including impacts from global health crises, geopolitical tensions, such as the ongoing conflicts between Russia and Ukraine, conflict in the Middle East, and increasing tensions between China and Taiwan, and government actions implemented as a result of the foregoing, fluctuations in inflation, rising interest rates, uncertainty and liquidity concerns in the broader financial services industry, and a potential recession in the United States. Estimates and assumptions about future events and their effects cannot be determined with certainty and therefore require the exercise of judgment. As of the date of issuance of these condensed consolidated financial statements, the Company is not aware of any specific event or circumstance that would require the Company to update its estimates, assumptions and judgments or revise the reported amounts of assets and liabilities or the disclosure of contingent assets and liabilities. These estimates, however, may change as new events occur and additional information is obtained, and are recognized in the condensed consolidated financial statements as soon as they become known. Actual results could differ materially from the Company’s estimates and assumptions.
Significant Accounting Policies	Significant Accounting Policies There have been no material changes to the significant accounting policies previously disclosed in Note 2 to the Consolidated Financial Statements in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023.
Accounting Pronouncements Recently Issued	Accounting Pronouncements Recently Adopted In November 2023, the Financial Accounting Standards Board, or FASB, issued Accounting Standards Update, or ASU, 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, or ASU 2023-07, which expanded the disclosures for reportable segments made by public entities. These amendments within ASU 2023-07 retained the existing disclosure requirements in ASC 280 and expanded upon them to require public entities to disclose significant expenses for reportable segments in both interim and annual reporting periods, as well as items that were previously disclosed only annually on an interim basis, including disclosures related to a reportable segment’s profit or loss and assets. In addition, entities with a single reportable segment must provide all segment disclosures required in ASC 280, including the new disclosures for reportable segments under the amendments in ASU 2023-07. The amendments did not change the existing guidance on how a public entity identified and determined its reportable segments. A public entity should apply the amendments in ASU 2023-07 retrospectively to all prior periods presented in the financial statements. Upon transition, the segment expense categories and amounts disclosed in the prior periods should be based on the significant segment expense categories identified and disclosed in the period of adoption. The amendments in ASU 2023-07 are effective for annual periods for all public entities in fiscal years beginning after December 15, 2023, and in interim periods within fiscal years beginning after December 15, 2024. The Company adopted ASU 2023-07 on January 1, 2024, and expects to comply with any new applicable disclosures in its Annual Report on Form 10-K for the year ended December 31, 2024. The Company does not expect the adoption to have a material effect on its results of operations, financial position, and cash flows. Accounting Pronouncements Not Yet Adopted In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, or ASU 2023-09, which applies to all entities subject to income taxes. ASU 2023-09 requires disaggregated information about a reporting entity’s effective tax rate reconciliation as well as information on income taxes paid. ASU 2023-09 is intended to provide more detailed income tax disclosures. For public business entities (PBEs), the new requirements will be effective for annual periods beginning after December 15, 2024. ASU 2023-09 will be applied on a prospective basis with the option to apply the standard retrospectively. The Company expects to adopt ASU 2023-09 on January 1, 2025, and it does not expect the adoption to have a material effect on its results of operations, financial position, and cash flows.

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Revenue:
Total revenue	$ 991	$ 6,933	$ 3,126	$ 13,098
Operating expenses:
Cost of goods sold		1,418	620	4,008
Research and development	9,308	30,310	31,272	54,644
General and administrative	6,408	7,545	13,224	14,436
Restructuring	2,581		4,982
Total operating expenses	18,297	39,273	50,098	73,088
Operating loss	(17,306)	(32,340)	(46,972)	(59,990)
Other income, net	689	861	1,641	1,846
Loss on inventory write-down	(1,489)		(1,489)
Non-cash interest expense on liability related to sales of future royalties and milestones	(1,910)		(3,892)
Net loss	$ (20,016)	$ (31,479)	$ (50,712)	$ (58,144)
Net loss per share:
Basic	$ (0.37)	$ (0.58)	$ (0.93)	$ (1.08)
Diluted	$ (0.37)	$ (0.58)	$ (0.93)	$ (1.08)
Weighted average shares:
Basic	54,724,692	54,002,988	54,656,391	53,937,875
Diluted	54,724,692	54,002,988	54,656,391	53,937,875
Other comprehensive income, net of tax of $0:
Change in unrealized gains on available-for-sale marketable securities	$ 70	$ 371	$ 139	$ 942
Total comprehensive loss	(19,946)	(31,108)	(50,573)	(57,202)
Collaborative revenue
Revenue:
Total revenue		5,410	788	8,160
Commercial supply revenue
Revenue:
Total revenue		1,400	640	4,591
Royalty revenue
Revenue:
Total revenue		$ 123		248
Clinical compound revenue
Revenue:
Total revenue			84	$ 99
Other revenue
Revenue:
Total revenue	$ 991		$ 1,614

Accumulated Other Comprehensive Loss - Summary of Changes in Accumulated Other Comprehensive (Loss) Income, Net of Tax, from Unrealized Gains (Losses) on Available-for-Sale Marketable Securities (Detail) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2024	Jun. 30, 2023
Accumulated Other Comprehensive Loss [Line Items]
Balance, Value	$ 29,803	$ 57,085	$ 136,598	$ 158,779	$ 57,085	$ 158,779
Amount reclassified from accumulated other comprehensive loss	0		0		0	0
Net current period other comprehensive income	70	69	371	571
Balance, Value	11,598	29,803	108,932	136,598	11,598	108,932
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Loss [Line Items]
Balance, Value	(191)	(260)	(1,101)	(1,672)	(260)	(1,672)
Other comprehensive income before reclassifications					139	942
Net current period other comprehensive income	70	69	371	571	139	942
Balance, Value	$ (121)	$ (191)	$ (730)	$ (1,101)	$ (121)	$ (730)

- 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

- Definition

Amount after tax and reclassification adjustments of other comprehensive income (loss).

+ References

+ Details

- Definition

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

+ References

+ Details

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023	Dec. 31, 2015	Jan. 01, 2024	Nov. 20, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, par value	$ 0.001		$ 0.001		$ 0.001
Common stock, shares outstanding	54,837,764		54,837,764		54,480,704
Common stock, shares issued	54,837,764		54,837,764		54,480,704
Number of options outstanding	6,067,881		6,067,881		7,897,647
Options granted			3,045,125
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 1,420	$ 2,881	$ 3,153	$ 5,602
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 321	$ 561	$ 1,933	$ 1,193
Non-employee Directors [Member] \| Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units, grant date fair value	$ 0.66		$ 0.66
Employees And Non-Employee Members Of Board Of Directors [Member] \| Share-based Payment Arrangement, Employee [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of options granted	$ 0.66	$ 2.43	$ 0.86	$ 6.18
Employees And Non-Employee Members Of Board Of Directors [Member] \| Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units, grant date fair value		$ 3.09		$ 7.81
Non-employee Consultants [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted	0	0	0	0
2014 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, number of shares authorized					12,203,023		13,837,444
Number of stock options that may be granted after the tenth anniversary of the 2014 Plan			0
Annual increases in number of shares reserved for issuance as a percentage of shares of capital stock outstanding through January 1, 2024						3.00%
Options granted	1,170,000	349,767	3,045,125	1,798,921
2014 Equity Incentive Plan [Member] \| Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awarded	903,883	194,172	903,883	601,172
2014 Equity Incentive Plan [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Term of awards granted			10 years
2014 Equity Incentive Plan [Member] \| Maximum [Member] \| Incentive Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, number of shares authorized						30,000,000
2014 Equity Incentive Plan [Member] \| Director [Member] \| Incentive Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of awards granted			3 years
2014 Equity Incentive Plan [Member] \| Employee And Nonemployee Consultants [Member] \| Share-Based Compensation Award, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of vested shares on first anniversary of grant date			25.00%
2014 Equity Incentive Plan [Member] \| Employee And Nonemployee Consultants [Member] \| Share-based Compensation Award, Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of awards granted			36 months
2014 Equity Incentive Plan [Member] \| Employee And Nonemployee Consultants [Member] \| Share Based Compensation Subsequent Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of awards granted			4 years
2014 Equity Incentive Plan [Member] \| Employees And Non-Employee Members Of Board Of Directors [Member] \| Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awarded			903,883
Restricted stock units, grant date fair value			$ 0.66
2019 Inducement Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, par value								$ 0.001
Awarded	0	0	0	0	0
2019 Inducement Plan [Member] \| Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awarded	0	0	0	0
2019 Inducement Plan [Member] \| Share-Based Compensation Award, Tranche One [Member] \| Share-based Payment Arrangement, Employee [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of vested shares on first anniversary of grant date			25.00%
2019 Inducement Plan [Member] \| Share-based Compensation Award, Tranche Two [Member] \| Share-based Payment Arrangement, Employee [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of awards granted			36 months
2019 Inducement Plan [Member] \| Share Based Compensation Subsequent Awards [Member] \| Share-based Payment Arrangement, Employee [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of awards granted			4 years
2019 Inducement Plan [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, number of shares authorized								300,000

Accounts Payable and Accrued Expenses - Schedule of Accounts Payable and Accrued Expenses (Detail) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Accounts Payable and Accrued Expenses
Accounts payable	$ 6,755	$ 11,583
Accrued research projects	1,010	4,343
Accrued compensation and benefits	1,214	6,519
Accrued professional fees and other	4,754	3,147
Total	$ 13,733	$ 25,592

Inventory, net - Schedule of Inventories (Detail) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Inventory, net
Raw materials	$ 2,124	$ 2,639
Work-in-process	1,009	708
Inventory gross	3,133	3,347
Less Inventory Reserve for Obsolescence	(1,489)	(526)
Total	$ 1,644	$ 2,821

Related Party Transactions (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Collaboration and licensing agreements
Accounts due from related parties	$ 359		$ 359		$ 2,765
Revenue from contract with customer	991	$ 6,933	3,126	$ 13,098
Accrued professional fees and other	$ 4,754		4,754		3,147
Commercial supply revenue
Collaboration and licensing agreements
Revenue from contract with customer		1,400	640	4,591
Collaborative revenue
Collaboration and licensing agreements
Revenue from contract with customer		5,410	$ 788	8,160
Royalty revenue
Collaboration and licensing agreements
Revenue from contract with customer		123		248
Affiliated Entity \| Vifor International Ltd.
Collaboration and licensing agreements
Shares owned as a result of upfront and milestone payments	7,396,770		7,396,770
Related party ownership percentage	13.50%		13.50%
Affiliated Entity \| CSL Vifor
Collaboration and licensing agreements
Accounts due from related parties	$ 359		$ 359		$ 2,765
Affiliated Entity \| CSL Vifor \| Commercial supply revenue
Collaboration and licensing agreements
Revenue from related parties		1,400	640	4,591
Affiliated Entity \| CSL Vifor \| Other Non-Cash Revenue
Collaboration and licensing agreements
Revenue from related parties	359	0	649	0
Affiliated Entity \| CSL Vifor \| CSL Vifor Profit Sharing \| Collaborative revenue
Collaboration and licensing agreements
Revenue from contract with customer		5,410	788	8,160
Accrued professional fees and other	1,447		1,447
Affiliated Entity \| CSL Vifor \| CSL Vifor Kapruvia \| Royalty revenue
Collaboration and licensing agreements
Revenue from contract with customer	$ 0	$ 123	$ 0	$ 248