0001628280-23-015212 | 10-Q | XBRL Viewer

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CONDENSED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 92,487	$ 96,140
Short-term investments	37,886	27,769
Accounts receivable	12,120	7,733
Inventory	4,823	3,282
Prepaid commercial manufacturing	13,835	13,567
Prepaid expenses and other current assets	5,896	5,112
Total current assets	167,047	153,603
Inventory, non-current	40,124	25,064
Right-of-use assets	7,972	9,295
Property and equipment, net	1,102	1,223
Other assets	774	881
Total assets	217,019	190,066
Current liabilities:
Accounts payable	10,513	10,859
Accrued compensation and benefits	5,074	7,548
Current portion of long-term debt	26,880	26,711
Current portion of operating lease liability	3,998	3,894
Deferred revenue	5,545	4,211
Accrued expenses and other current liabilities	11,053	12,380
Total current liabilities	63,063	65,603
Operating lease liability, net of current portion	4,814	5,855
Deferred revenue, non-current	11,498	9,025
Deferred royalty obligation related to the sale of future royalties	12,223	11,254
Total liabilities	91,598	91,737
Commitments and contingencies (Note 14)
Stockholders’ equity:
Preferred stock, $0.0001 par value; 5,000,000 shares authorized; no shares issued and outstanding as of March 31, 2023 and December 31, 2022, respectively.	0	0
Common stock, $0.0001 par value; 300,000,000 shares authorized; 214,462,050 and 198,575,016 shares issued and outstanding as of March 31, 2023 and December 31, 2022, respectively.	21	20
Additional paid-in capital	932,330	878,500
Accumulated deficit	(806,910)	(780,137)
Accumulated other comprehensive loss	(20)	(54)
Total stockholders’ equity	125,421	98,329
Total liabilities and stockholders’ equity	$ 217,019	$ 190,066

Borrowing (Tables)

3 Months Ended

Mar. 31, 2023

Debt Disclosure [Abstract]

Schedule of Future Debt Payment Obligations

As of March 31, 2023, our future payment obligations related to the 2022 Loan, excluding interest payments and the 2022 final fee, were as follows (in thousands) and may be condensed to the 24 months ending March 1, 2027 if certain conditions noted above to extend the interest-only period are achieved:


Total repayment obligations	$	28,861
Less: Unamortized discount and debt issuance costs	(1,282)
Less: Unaccreted value of final fee	(699)
Long-term debt	26,880
Less: Current portion of long-term debt	(26,880)
Long-term debt, net of current portion	$	—

Fair Value Measurements - Financial Assets and Liabilities Measured on a Recurring Basis (Details) - Recurring - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Assets:
Assets, fair value	$ 122,387	$ 112,082
Liabilities:
Liabilities, fair value	1,726	1,656
Derivative liabilities for exit fees
Liabilities:
Liabilities, fair value	1,726	1,656
Money market funds
Assets:
Assets, fair value	84,501	84,313
Commercial paper
Assets:
Assets, fair value	23,333	25,291
Corporate bonds
Assets:
Assets, fair value		999
U.S. government-sponsored agency bonds
Assets:
Assets, fair value	12,620	1,479
Asset-backed securities
Assets:
Assets, fair value	1,933
Level 1
Assets:
Assets, fair value	84,501	84,313
Liabilities:
Liabilities, fair value	0	0
Level 1 \| Derivative liabilities for exit fees
Liabilities:
Liabilities, fair value	0	0
Level 1 \| Money market funds
Assets:
Assets, fair value	84,501	84,313
Level 1 \| Commercial paper
Assets:
Assets, fair value	0	0
Level 1 \| Corporate bonds
Assets:
Assets, fair value		0
Level 1 \| U.S. government-sponsored agency bonds
Assets:
Assets, fair value	0	0
Level 1 \| Asset-backed securities
Assets:
Assets, fair value	0
Level 2
Assets:
Assets, fair value	37,886	27,769
Liabilities:
Liabilities, fair value	0	0
Level 2 \| Derivative liabilities for exit fees
Liabilities:
Liabilities, fair value	0	0
Level 2 \| Money market funds
Assets:
Assets, fair value	0	0
Level 2 \| Commercial paper
Assets:
Assets, fair value	23,333	25,291
Level 2 \| Corporate bonds
Assets:
Assets, fair value		999
Level 2 \| U.S. government-sponsored agency bonds
Assets:
Assets, fair value	12,620	1,479
Level 2 \| Asset-backed securities
Assets:
Assets, fair value	1,933
Level 3
Assets:
Assets, fair value	0	0
Liabilities:
Liabilities, fair value	1,726	1,656
Level 3 \| Derivative liabilities for exit fees
Liabilities:
Liabilities, fair value	1,726	1,656
Level 3 \| Money market funds
Assets:
Assets, fair value	0	0
Level 3 \| Commercial paper
Assets:
Assets, fair value	0	0
Level 3 \| Corporate bonds
Assets:
Assets, fair value		0
Level 3 \| U.S. government-sponsored agency bonds
Assets:
Assets, fair value	0	$ 0
Level 3 \| Asset-backed securities
Assets:
Assets, fair value	$ 0

Collaboration and Licensing Agreements - Deferred Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Deferred revenue - current
Beginning balance	$ 4,211
Ending balance	5,545
Deferred revenue - non-current
Beginning balance	9,025
Ending balance	11,498
2017 KKC Agreement
Deferred revenue - current
Beginning balance	4,211	$ 0
Increases due to amounts reclassified from non-current, to be recognized in the next twelve months	809
Increases to amounts invoiced, for which cash has not yet been received	525	0
Ending balance	5,545	0
Deferred revenue - non-current
Beginning balance	9,025	4,727
Increases to amounts invoiced, for which cash has not yet been received	3,282	3,829
Increase due to unbilled prepayments recorded during the period	0	7
Decreases due to amounts reclassified as current, to be recognized in the next twelve months	(809)	0
Ending balance	$ 11,498	$ 8,563

Collaboration and Licensing Agreements - Narrative (Details) $ in Thousands, $ in Millions, ¥ in Billions	1 Months Ended				3 Months Ended			65 Months Ended
	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Nov. 30, 2017 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2023 USD ($)	Mar. 31, 2023 CAD ($)	Mar. 31, 2022 USD ($)	Mar. 31, 2023 USD ($)	Mar. 31, 2023 JPY (¥)	Oct. 31, 2022 USD ($)	Apr. 30, 2022 USD ($) payment_tranche
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenues					$ 11,369		$ 468
Cost of revenue					1,537		85
Licensing revenue
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenues					12		4
2017 KKC Agreement \| Licensing revenue
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total revenues								$ 20,000
KKC \| 2017 KKC Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront license fees			$ 30,000
Potential development milestones			$ 55,000
Potential commercialization milestones					64,100			64,100	¥ 8.5
Fee receivable for reduction in royalty rate											$ 40,000
Number of payment tranches for fee receivable for reduction in royalty rate \| payment_tranche											2
KKC \| 2017 KKC Agreement \| Licensing revenue
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Proceeds from milestone payments										$ 35,000
Fosun Pharma \| Fosun Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential development milestones					3,000			3,000
Upfront payment received		$ 12,000
Potential development and commercialization milestones					$ 110,000
Threshold percentage of net sales for tiered royalties					20.00%	20.00%
Knight \| Knight Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential development milestones					$ 700			700
Upfront payment received	$ 2,300
Potential development and commercialization milestones					16,300	$ 22.2
AstraZeneca \| AZ Termination Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Percentage of royalty revenue				10.00%
Percentage of non-royalty revenue				20.00%
Maximum potential payment per agreement				$ 75,000
Aggregate cost of revenue recognized					16,400			16,400
Aggregate amount paid					11,900			$ 11,900
Cost of revenue					$ 1,200		$ 100

Cover - shares	3 Months Ended
Cover - shares	Mar. 31, 2023	Apr. 28, 2023
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2023
Document Transition Report	false
Entity File Number	001-36485
Entity Registrant Name	ARDELYX, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	26-1303944
Entity Address, Address Line One	400 Fifth Avenue
Entity Address, Address Line Two	Suite 210
Entity Address, City or Town	Waltham
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02451
City Area Code	510
Local Phone Number	745-1700
Title of 12(b) Security	Common Stock, par value $0.0001
Trading Symbol	ARDX
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		214,462,429
Entity Central Index Key	0001437402
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q1
Amendment Flag	false

CONDENSED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Revenues:
Total revenues	$ 11,369	$ 468
Operating expenses:
Cost of revenue	1,537	85
Research and development	9,093	8,851
Selling, general and administrative	26,803	19,339
Total operating expenses	37,433	28,275
Loss from operations	(26,064)	(27,807)
Interest expense	(1,028)	(746)
Non-cash interest expense related to the sale of future royalties	(969)	0
Other income, net	1,302	484
Loss before provision for income taxes	(26,759)	(28,069)
Provision for income taxes	14	2
Net loss	$ (26,773)	$ (28,071)
Net loss per common stock - basic (in dollars per share)	$ (0.13)	$ (0.21)
Net loss per common stock - diluted (in dollars per share)	$ (0.13)	$ (0.21)
Shares used in computing net loss per share - basic (in shares)	207,023,127	130,934,795
Shares used in computing net loss per share - diluted (in shares)	207,023,127	130,934,795
Comprehensive loss:
Net loss	$ (26,773)	$ (28,071)
Unrealized gains (losses) on available-for-sale securities	34	(82)
Comprehensive loss	(26,739)	(28,153)
Product sales, net
Revenues:
Total revenues	11,355	450
Product supply revenue
Revenues:
Total revenues	2	14
Licensing revenue
Revenues:
Total revenues	$ 12	$ 4

Stockholders' Equity (Details) - USD ($) $ / shares in Units, shares in Millions	1 Months Ended	3 Months Ended
	Jan. 31, 2023	Mar. 31, 2023	Mar. 31, 2022	Aug. 31, 2021
Subsidiary, Sale of Stock [Line Items]
Proceeds from issuance of common stock in at the market offering, net of issuance costs		$ 50,719,000	$ 5,921,000
Common stock
Subsidiary, Sale of Stock [Line Items]
Maximum aggregate offering price	$ 250,000,000
2021 Open Market Sales Agreement
Subsidiary, Sale of Stock [Line Items]
Commission on sale of stock per agreement (percent)		3.00%
Issuance of common stock in at the market offering (in shares)		15.5
Proceeds from issuance of common stock in at the market offering, net of issuance costs		$ 51,900,000
Weighted-average sales price per share (in dollars per share)		$ 3.35
Total of shares sold		95.2
Total of gross proceeds		$ 150,000,000
2021 Open Market Sales Agreement \| Common stock
Subsidiary, Sale of Stock [Line Items]
Maximum aggregate offering price				$ 150,000,000
Open Market Sales Agreement 2023, At The Market Offering
Subsidiary, Sale of Stock [Line Items]
Commission on sale of stock per agreement (percent)	3.00%
Open Market Sales Agreement 2023, At The Market Offering \| Common stock
Subsidiary, Sale of Stock [Line Items]
Maximum aggregate offering price	$ 150,000,000

Derivative Liabilities (Tables)

3 Months Ended

Mar. 31, 2023

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Schedule of Changes in Fair Value of Derivative Liability

Changes in the fair value of recurring measurements included in Level 3 of the fair value hierarchy are presented as other income, net in our condensed statements of operations and comprehensive loss and were as follows for the three months ended March 31, 2023 and 2022 (in thousands):


	2023		2022
Balance at January 1,	$	1,656	$	698
2022 Exit Fee addition at fair value	—		375
Changes in estimated fair value:
2018 Exit Fee	48		15
2022 Exit Fee	22		—
Balance at March 31,	$	1,726	$	1,088

Leases - Undiscounted Cash Payment Obligations (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Undiscounted cash payment obligations
Remainder of 2023	$ 3,343
2024	4,589
2025	1,321
2026	252
Thereafter	0
Total undiscounted operating lease payments	9,505
Imputed interest expenses	(693)
Total operating lease liabilities	8,812	$ 9,749
Less: Current portion of operating lease liability	(3,998)	(3,894)
Operating lease liability, net of current portion	$ 4,814	$ 5,855

Inventory - Narrative (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Inventory Disclosure [Abstract]
Prepaid commercial manufacturing	$ 13,835	$ 13,567

Derivative Liabilities

3 Months Ended

Mar. 31, 2023

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Derivative Liabilities

DERIVATIVE LIABILITIES

2018 Exit Fee

In May 2018, in connection with entering into the 2018 Loan Agreement, we entered into an agreement pursuant to which we agreed to pay $1.5 million in cash ("2018 Exit Fee") upon any change of control transaction in respect of the Company or if we obtain both (i) FDA approval of XPHOZAH and (ii) FDA approval of IBSRELA, which was obtained on September 12, 2019 (“2018 Exit Fee Agreement”). Notwithstanding the February 2022 prepayment of the 2018 Loan, our obligation to pay the 2018 Exit Fee will expire on May 16, 2028. We concluded that the 2018 Exit Fee is a freestanding derivative which should be accounted for at fair value on a recurring basis. The estimated fair value of the 2018 Exit Fee is recorded as a derivative liability and included in accrued expense and other current liabilities on the accompanying condensed balance sheets. As of March 31, 2023 and December 31, 2022, the estimated fair value of the 2018 Exit Fee was $1.3 million and $1.2 million, respectively.

The fair value of the derivative liability was determined using a discounted cash flow analysis and is classified as a Level 3 measurement within the fair value hierarchy since our valuation utilized significant unobservable inputs. Specifically, the key assumptions included in the calculation of the estimated fair value of the derivative instrument include: (i) our estimates of both the probability and timing of a potential $1.5 million payment to Solar Capital Ltd. and Western Alliance Bank as a result of the FDA approvals, and (ii) a discount rate which was derived from our estimated cost of debt, adjusted with current LIBOR. Generally, increases or decreases in the probability of occurrence would result in a directionally similar impact in the fair value measurement of the derivative instrument and it is estimated that a 10% increase (decrease), not to exceed 100%, in the probability of occurrence would result in a fair value fluctuation of no more than $0.1 million.

2022 Exit Fee

In February 2022, in connection with entering into the 2022 Loan Agreement, we entered into an agreement, whereby we agreed to pay an exit fee in the amount of 2% of the 2022 Loan funded (“2022 Exit Fee”) upon (i) any change of control transaction or (ii) our achievement of net revenue from the sale of any products equal to or greater than $100.0 million, measured on a six (6) months basis ("Revenue Milestone"), tested monthly at the end of each month. Notwithstanding the prepayment or termination of the 2022 Loan, the 2022 Exit Fee will expire on February 23, 2032. We concluded that the 2022 Exit Fee is a freestanding derivative which should be accounted for at fair value on a recurring basis. The estimated fair value of the 2022 Exit Fee is recorded as a derivative liability and included in accrued expenses and other current liabilities on the accompanying condensed balance sheets. As of March 31, 2023 and December 31, 2022, the estimated fair value of the 2022 Exit Fee was $0.5 million and $0.4 million, respectively.

The fair value of the derivative liability was determined using a discounted cash flow analysis and is classified as a Level 3 measurement within the fair value hierarchy since our valuation utilized significant unobservable inputs. Specifically, the key assumptions included in the calculation of the estimated fair value of the 2022 derivative liability include: (i) our estimates of both the probability and timing of achieving the Revenue Milestone and (ii) the probability and timing of funding the Term B Loan, which is dependent upon (a) approval by the FDA for our NDA for the control of serum phosphorus in adult patients with CKD on dialysis by November 30, 2023, and (b) achievement of certain product revenue milestone targets. Generally, increases or decreases in the probability of occurrence would result in a directionally similar impact in the fair value measurement of the derivative liability and it is estimated that a 10% increase (decrease) in the probability of occurrence would not result in a material fair value fluctuation.


	2023		2022
Balance at January 1,	$	1,656	$	698
2022 Exit Fee addition at fair value	—		375
Changes in estimated fair value:
2018 Exit Fee	48		15
2022 Exit Fee	22		—
Balance at March 31,	$	1,726	$	1,088

Equity Incentive Plans - Narrative (Details) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2023 USD ($) $ / shares shares
Board of directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of common stock for services (in shares)	0
ESPP shares issuable
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of common stock under employee stock purchase plan (in shares)	200,000
Purchase price (in dollars per share) \| $ / shares	$ 0.83
Proceeds from ESPP \| $	$ 0.1

Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2023

Fair Value Disclosures [Abstract]

Schedule of Fair Value of Financial Assets and Liabilities Measured on a Recurring Basis

The following table sets forth the fair value of our financial assets and liabilities that are measured or disclosed on a recurring basis by level within the fair value hierarchy (in thousands):


	March 31, 2023
	Total Fair Value		Level 1		Level 2		Level 3
Assets:
Money market funds	$	84,501	$	84,501	$	—	$	—
Commercial paper	23,333		—		23,333		—
U.S. government-sponsored agency bonds	12,620		—		12,620		—

Asset-backed securities	1,933		—		1,933		—

Total	$	122,387	$	84,501	$	37,886	$	—

Liabilities:
Derivative liabilities for exit fees	$	1,726	$	—	$	—	$	1,726
Total	$	1,726	$	—	$	—	$	1,726


	December 31, 2022
	Total Fair Value		Level 1		Level 2		Level 3
Assets:
Money market funds	$	84,313	$	84,313	$	—	$	—
Commercial paper	25,291		—		25,291		—
Corporate bonds	999		—		999		—
U.S. government-sponsored agency bonds	1,479		—		1,479		—


Total	$	112,082	$	84,313	$	27,769	$	—

Liabilities:
Derivative liability for exit fee	$	1,656	$	—	$	—	$	1,656
Total	$	1,656	$	—	$	—	$	1,656

Cash, Cash Equivalents and Investments (Tables)

3 Months Ended

Mar. 31, 2023

Cash and Cash Equivalents [Abstract]

Schedule of Securities Classified as Cash, Cash Equivalents and Investments

Securities classified as cash, cash equivalents and short-term investments as of March 31, 2023 and December 31, 2022 are summarized below (in thousands):


	March 31, 2023
			Gross Unrealized
	Amortized Cost		Gains		Losses		Fair Value
Cash and cash equivalents:
Cash	$	7,986	$	—	$	—	$	7,986
Money market funds	84,501		—		—		84,501


Total cash and cash equivalents	92,487		—		—		92,487
Short-term investments:
Commercial paper	$	23,353	$	3	$	(23)	$	23,333
U.S. government-sponsored agency bonds	12,618		8		(6)		12,620

Asset backed securities	1,935		—		(2)		1,933
Total short-term investments	37,906		11		(31)		37,886
Total cash, cash equivalents and investments	$	130,393	$	11	$	(31)	$	130,373


	December 31, 2022
			Gross Unrealized
	Amortized Cost		Gains		Losses		Fair Value
Cash and cash equivalents:
Cash	$	11,827	$	—	$	—	$	11,827
Money market funds	84,313		—		—		84,313


Total cash and cash equivalents	96,140		—		—		96,140
Short-term investments
Commercial paper	$	25,336	$	6	$	(51)	$	25,291
Corporate bonds	1,000		—		(1)		999
U.S. government-sponsored agency bonds	1,487		—		(8)		1,479

Total short-term investments	27,823		6		(60)		27,769


Total cash, cash equivalents and investments	$	123,963	$	6	$	(60)	$	123,909

Product Revenue, Net - Gross-to-Net Sales Accruals (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($)
Gross-to-net sales accruals and reserves
Beginning balance	$ 2,844
Provisions	5,760
Credits/payments	(4,320)
Ending balance	4,284
Discounts and Chargebacks
Gross-to-net sales accruals and reserves
Beginning balance	142
Provisions	824
Credits/payments	(726)
Ending balance	240
Rebates, Wholesaler and GPO Fees
Gross-to-net sales accruals and reserves
Beginning balance	1,444
Provisions	2,361
Credits/payments	(1,685)
Ending balance	2,120
Copay and Returns
Gross-to-net sales accruals and reserves
Beginning balance	1,258
Provisions	2,575
Credits/payments	(1,909)
Ending balance	$ 1,924

Equity Incentive Plans - Unrecognized Stock-Based Compensation (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($)
Options to purchase common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized Compensation Expense	$ 21,127
Average Remaining Vesting Period (Years)	3 years 2 months 12 days
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized Compensation Expense	$ 7,309
Average Remaining Vesting Period (Years)	3 years 3 months 18 days
ESPP shares issuable
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized Compensation Expense	$ 292
Average Remaining Vesting Period (Years)	3 months 18 days

Stockholders' Equity	3 Months Ended
Stockholders' Equity	Mar. 31, 2023
Stockholders' Equity Note [Abstract]
Stockholders' Equity	STOCKHOLDERS’ EQUITY At the Market Offerings Agreement In August 2021, we filed an additional prospectus supplement under a Registration Statement which was filed in July 2020 for the offering, issuance and sale by us of up to a maximum aggregate offering price of $150.0 million of our common stock that may be issued and sold, from time to time, under a sales agreement we entered into with Jefferies (the "2021 Open Market Sales Agreement"), pursuant to which we may, from time to time, sell up to $150.0 million in shares of our common stock through Jefferies. Pursuant to the 2021 Open Market Sales Agreement, Jefferies, as our sales agent, received a commission of up to 3% of the gross sales price for shares of common stock sold under the 2021 Open Market Sales Agreement. During the three months ended March 31, 2023 we sold 15.5 million shares and received gross proceeds of $51.9 million at a weighted average sales price of approximately $3.35 per share under the 2021 Open Market Sales Agreement. As of March 31, 2023, we have sold a total of 95.2 million shares and received the maximum gross proceeds of $150.0 million under the 2021 Open Market Sales Agreement. In January 2023, we filed a Form S-3 registration statement, which became effective in January 2023 ("2023 Registration Statement"), containing (i) a base prospectus for the offering, issuance and sale by us of up to a maximum aggregate offering price of $250.0 million of our common stock, preferred stock, debt securities, warrants and/or units, from time to time in one or more offerings; and (ii) a prospectus supplement for the offering, issuance and sale by us of up to a maximum aggregate offering price of $150.0 million of our common stock that may be issued and sold, from time to time, under a sales agreement with Jefferies LLC ("Jefferies"), deemed to be “at-the-market offerings” ("2023 Open Market Sales Agreement"). Pursuant to the 2023 Open Market Sales Agreement, Jefferies, as sales agent, may receive a commission of up to 3.0% of the gross sales price for shares of common stock sold under the 2023 Open Market Sales Agreement. As of March 31, 2023, there have been no sales of our common stock under the 2023 Open Market Sales Agreement.

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-URI https://asc.fasb.org/topic&trid=2208762

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126973232&loc=SL123496158-112644

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 13
-URI https://asc.fasb.org/extlink&oid=126973232&loc=SL123496158-112644

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 14
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=126973232&loc=SL123496171-112644

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
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+ Details

Leases

3 Months Ended

Mar. 31, 2023

Leases [Abstract]

Leases

LEASES

All of our leases are operating leases and each contain customary rent escalation clauses. Certain of the leases have both lease and non-lease components. We have elected to account for each separate lease component and the non-lease components associated with that lease component as a single lease component for all classes of underlying assets.

The following table provides additional details of our facility leases presented in our condensed balance sheets (dollars in thousands):


Facilities	March 31, 2023			December 31, 2022
Right-of-use assets	$	7,972		$	9,295

Current portion of lease liabilities	3,998			3,894
Operating lease liability, net of current portion	4,814			5,855
Total	$	8,812		$	9,749

Weighted-average remaining life (years)	2.2			2.4
Weighted-average discount rate	6.8		%	6.8		%

The lease costs, which are included in operating expenses in our condensed statements of operations and comprehensive loss, were as follows (in thousands):


	Three Months Ended March 31,
	2023		2022
Operating lease expense	$	1,064	$	1,064
Cash paid for operating lease	$	1,098	$	1,058

The following table summarizes our undiscounted cash payment obligations for our operating lease liabilities as of March 31, 2023 (in thousands):


Remainder of 2023	$	3,343
2024	4,589
2025	1,321
2026	252

Thereafter	—
Total undiscounted operating lease payments	9,505
Imputed interest expenses	(693)
Total operating lease liabilities	8,812
Less: Current portion of operating lease liability	(3,998)
Operating lease liability, net of current portion	$	4,814

In March 2023, we entered into a sub-lease Agreement (the “Sub-lease”) with Chronus Health, Inc. ("Chronus). The Sub-lease permits use by Chronus of a portion of the space in our facility in Fremont, California. We lease the facility from a different counterparty under a separate head lease that commenced in September 2008 and has been amended multiple times to add space and to extend the lease term through March 2025. We have sub-leased to Chronus approximately 21,644 square feet of the 72,500 square foot building's interior space, plus corresponding exterior support space and parking. The term of the Sub-lease shall expire on February 1, 2025.

In accordance with the Sub-lease we recognized an impairment of long-lived assets totaling $0.4 million during the three months ended March 31, 2023, which consisted primarily of impairment to the Fremont facility right-of-use asset. The Sub-lease commenced in April 2023 and we have recognized no income from the sub-lease as of March 31, 2023.

Organization and Basis of Presentation	3 Months Ended
Organization and Basis of Presentation	Mar. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Basis of Presentation	ORGANIZATION AND BASIS OF PRESENTATION Ardelyx, Inc. (“Company,” “we,” “us” or “our”) is a biopharmaceutical company founded with a mission to discover, develop and commercialize innovative, first-in-class medicines that meet significant unmet medical needs. We developed a unique and innovative platform that enabled the discovery of new biological mechanisms and pathways to develop potent and efficacious therapies that minimize the side effects and drug-drug interactions frequently encountered with traditional, systemically absorbed medicines. The first molecule we discovered and developed was tenapanor, a targeted, first-in-class, oral, small molecule therapy. Tenapanor, branded as IBSRELA, is approved in the U.S. for the treatment of adults with irritable bowel syndrome with constipation (“IBS-C”). In April 2023, we resubmitted a New Drug Application (“NDA”) to the U.S. Food and Drug Administration (“FDA”) for the approval of XPHOZAH (tenapanor) for the control of serum phosphate in adult patients with chronic kidney disease (“CKD”) on dialysis who have had an inadequate response or intolerance to a phosphate binder therapy, under the brand name XPHOZAH. We also have a development stage asset, RDX013 for adult patients with CKD and/or heart failure with hyperkalemia, or elevated serum potassium, and a discovery phase asset, RDX020 for adult patients with metabolic acidosis, a serious electrolyte disorder, in patients with CKD. We operate in one business segment, which is the development and commercialization of biopharmaceutical products. Basis of Presentation These condensed financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and pursuant to the requirements of the Securities and Exchange Commission (“SEC”) for interim reporting. As permitted under those rules and regulations, certain footnotes or other financial information that are normally required by U.S. GAAP have been condensed or omitted. These condensed financial statements have been prepared on the same basis as our most recent annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments necessary to present fairly our financial position, results of operations, changes in stockholders’ equity, and cash flows for the interim periods presented. The accompanying condensed financial statements and related financial information should be read in conjunction with the audited financial statements and the related notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2022. The results for the three months ended March 31, 2023 are not necessarily indicative of results to be expected for the entire year ending December 31, 2023, or for any other interim period or future year. Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and judgments that affect the amounts reported in the financial statements and accompanying notes thereto. On an ongoing basis, management evaluates its estimates, including those related to recognition of revenue, clinical trial accruals, contract manufacturing accruals, utilization of inventory, fair value of assets and liabilities, income taxes and stock-based compensation. Management bases its estimates on historical experience and on various other market-specific and relevant assumptions that management believes to be reasonable under the circumstances. Actual results could materially differ from those estimates. Liquidity As of March 31, 2023, we had cash, cash equivalents and short-term investments of approximately $130.4 million. We have incurred operating losses since inception in 2007 and our accumulated deficit as of March 31, 2023 is $806.9 million. Our current level of cash, cash equivalents and short-term investments alone is not sufficient to meet our plans for the next twelve months following the issuance of these condensed financial statements on May 3, 2023. These factors raise substantial doubt regarding our ability to continue as a going concern for a period of one year from the issuance of these condensed financial statements. We plan to address our operating cash flow requirements with our current cash, cash equivalents and short-term investments, cash generated from product sales of IBSRELA, and if approved, cash generated from sales of XPHOZAH, our potential receipt of anticipated milestones payments from our collaboration partners, our potential receipt of anticipated payments from our Japanese collaboration partner under the second amendment to our License Agreement, with additional financing sources and through the implementation of cash preservation activities to reduce or defer discretionary spending. There are no assurances that our efforts to meet our operating cash flow requirements will be successful. If our current cash, cash equivalents and short-term investments as well as our plans to meet our operating cash flow requirements are not sufficient to fund necessary expenditures and meet our obligations for at least the next twelve months following the issuance of these financial statements, our liquidity, financial condition and business prospects will be materially affected. These financial statements have been prepared on a going concern basis and do not include any adjustments to the amounts and classification of assets and liabilities that may be necessary in the event that we can no longer continue as a going concern. Summary of Significant Accounting Policies Our significant accounting policies are described in Note 2 to our audited financial statements for the fiscal year ended December 31, 2022, included in our Annual Report on Form 10-K. There have been no material changes in our significant accounting policies as previously disclosed in our Annual Report on Form 10-K for the fiscal year ended December 31, 2022. Recent Accounting Pronouncements New Accounting Pronouncements - Recently Adopted We have adopted no new accounting pronouncements subsequent to filing our most recent Annual Report on Form 10-K. Recent Accounting Pronouncements Not Yet Adopted There were various accounting standards and interpretations issued recently, none of which are expected to have a material impact on our financial position, operations or cash flows.

Leases (Tables)

3 Months Ended

Mar. 31, 2023

Leases [Abstract]

Summary of Additional Details of Leases

The following table provides additional details of our facility leases presented in our condensed balance sheets (dollars in thousands):


Facilities	March 31, 2023			December 31, 2022
Right-of-use assets	$	7,972		$	9,295

Current portion of lease liabilities	3,998			3,894
Operating lease liability, net of current portion	4,814			5,855
Total	$	8,812		$	9,749

Weighted-average remaining life (years)	2.2			2.4
Weighted-average discount rate	6.8		%	6.8		%

Summary of Lease Costs

The lease costs, which are included in operating expenses in our condensed statements of operations and comprehensive loss, were as follows (in thousands):


	Three Months Ended March 31,
	2023		2022
Operating lease expense	$	1,064	$	1,064
Cash paid for operating lease	$	1,098	$	1,058

Summary of Undiscounted Cash Payment Obligations for Operating Lease Liabilities

The following table summarizes our undiscounted cash payment obligations for our operating lease liabilities as of March 31, 2023 (in thousands):


Remainder of 2023	$	3,343
2024	4,589
2025	1,321
2026	252

Thereafter	—
Total undiscounted operating lease payments	9,505
Imputed interest expenses	(693)
Total operating lease liabilities	8,812
Less: Current portion of operating lease liability	(3,998)
Operating lease liability, net of current portion	$	4,814

Net Loss Per Share - Computation of Net Loss Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Numerator:
Net loss	$ (26,773)	$ (28,071)
Denominator:
Weighted average common shares outstanding - basic (in shares)	207,023,127	130,934,795
Weighted average common shares outstanding - diluted (in shares)	207,023,127	130,934,795
Net loss per share of common stock - basic (in dollars per share)	$ (0.13)	$ (0.21)
Net loss per share of common stock - diluted (in dollars per share)	$ (0.13)	$ (0.21)

- 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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+ Details

Organization and Basis of Presentation (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($) segment	Dec. 31, 2022 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of segments \| segment	1
Cash and short-term investments	$ 130,373	$ 123,909
Accumulated deficit	$ 806,910	$ 780,137

Cash, Cash Equivalents and Investments - Narrative (Details) - investment	3 Months Ended	12 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Cash and Cash Equivalents [Abstract]
Short-term securities, contractual maturities maximum	1 year	1 year
Investment in continuous unrealized loss position for more than one year	0	0

Inventory

3 Months Ended

Mar. 31, 2023

Inventory Disclosure [Abstract]

Inventory

INVENTORY

We began capitalizing inventory during the fourth quarter of 2021, at which time our intent to commercialize IBSRELA was established and we commenced preparation for the commercial launch of IBSRELA. Inventory as of March 31, 2023 and December 31, 2022 consisted of the following (in thousands):


	March 31, 2023		December 31, 2022
Raw materials	$	21,702	$	22,299
Work in process	22,566		5,324
Finished goods	679		723
Total	$	44,947	$	28,346
Reported as:
Inventory	$	4,823	$	3,282
Inventory, non-current	40,124		25,064
Total	$	44,947	$	28,346

Prepaid commercial manufacturing of $13.8 million and $13.6 million as of March 31, 2023 and December 31, 2022, respectively, consisted of prepayments to third party contract manufacturing organizations for the manufacture of IBSRELA for production orders which we expect work to commence within the next 12 months.

Leases - Additional Details of Leases (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Right-of-use assets and lease liabilities
Right-of-use assets	$ 7,972	$ 9,295
Current portion of lease liabilities	3,998	3,894
Operating lease liability, net of current portion	4,814	5,855
Total operating lease liabilities	$ 8,812	$ 9,749
Additional details
Weighted-average remaining life (years)	2 years 2 months 12 days	2 years 4 months 24 days
Weighted-average discount rate	6.80%	6.80%

Equity Incentive Plans - Stock-Based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Stock-based Compensation [Line Items]
Stock-based compensation expense	$ 2,912	$ 3,722
Selling, general and administrative
Stock-based Compensation [Line Items]
Stock-based compensation expense	2,088	2,508
Research and development
Stock-based Compensation [Line Items]
Stock-based compensation expense	$ 824	$ 1,214

Borrowing - Future Payment Obligations (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Debt Disclosure [Abstract]
Total repayment obligations	$ 28,861
Less: Unamortized discount and debt issuance costs	(1,282)
Less: Unaccreted value of final fee	(699)
Long-term debt	26,880
Less: Current portion of long-term debt	(26,880)	$ (26,711)
Long-term debt, net of current portion	$ 0

- Definition

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

+ References + Details

CONDENSED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Income
Beginning balance (in shares) at Dec. 31, 2021		130,182,535
Beginning balance at Dec. 31, 2021	$ 82,617	$ 13	$ 795,540	$ (712,930)	$ (6)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under employee stock purchase plan (in shares)		127,100
Issuance of common stock under employee stock purchase plan	83		83
Issuance of common stock upon vesting of restricted stock units (in shares)		113,469
Issuance of common stock in at the market offering (in shares)		5,907,256
Issuance of common stock in at the market offering	5,921	$ 1	5,920
Stock-based compensation	3,722		3,722
Unrealized gains (losses) on available-for-sale securities	(82)				(82)
Net loss	(28,071)			(28,071)
Ending balance (in shares) at Mar. 31, 2022		136,330,360
Ending balance at Mar. 31, 2022	64,190	$ 14	805,265	(741,001)	(88)
Beginning balance (in shares) at Dec. 31, 2022		198,575,016
Beginning balance at Dec. 31, 2022	98,329	$ 20	878,500	(780,137)	(54)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under employee stock purchase plan (in shares)		165,969
Issuance of common stock under employee stock purchase plan	$ 138		138
Issuance of common stock upon exercise of options (in shares)	36,000	36,001
Issuance of common stock upon exercise of options	$ 62		62
Issuance of common stock upon vesting of restricted stock units (in shares)		207,773
Issuance of common stock in at the market offering (in shares)		15,477,291
Issuance of common stock in at the market offering	50,719	$ 1	50,718
Stock-based compensation	2,912		2,912
Unrealized gains (losses) on available-for-sale securities	34				34
Net loss	(26,773)			(26,773)
Ending balance (in shares) at Mar. 31, 2023		214,462,050
Ending balance at Mar. 31, 2023	$ 125,421	$ 21	$ 932,330	$ (806,910)	$ (20)

Subsequent Events	3 Months Ended
Subsequent Events	Mar. 31, 2023
Subsequent Events [Abstract]
Subsequent Events	SUBSEQUENT EVENTS[

Deferred Royalty Obligation Related To The Sale Of Future Royalties	3 Months Ended
	Mar. 31, 2023
Advance Royalties [Abstract]
Deferred Royalty Obligation Related To The Sale Of Future Royalties	DEFERRED ROYALTY OBLIGATION RELATED TO THE SALE OF FUTURE ROYALTIES In June 2022, we and HealthCare Royalty Partners IV, L.P. (“HCR”) entered into a Royalty and Sales Milestone Interest Acquisition Agreement (“HCR Agreement”). Under the terms of the HCR Agreement, HCR has agreed to pay us up to $20.0 million in exchange for the royalty payments and commercial milestone payments (collectively the “Royalty Interest Payments”) that we may receive under our 2017 License Agreement with Kyowa Kirin based upon Kyowa Kirin's net sales of tenapanor in Japan for hyperphosphatemia. As consideration for the sale of the Royalty Interest Payments, HCR paid to us a $10.0 million upfront payment, and we are eligible to receive a $5.0 million payment following Kyowa Kirin's receipt of regulatory approval to market tenapanor for hyperphosphatemia in Japan, and another $5.0 million payment in the event net sales by Kyowa Kirin in Japan exceed a certain annual target level by the end of 2025. The HCR Agreement is effective until terminated by the mutual agreement of the parties and contains customary representations and warranties and customary affirmative and negative covenants, including, among others, requirements as to prosecution, maintenance, defense and enforcement of certain patent rights in Japan, restrictions regarding our ability to forgive, release or reduce any Royalty Interest Payments due to us under the 2017 Kyowa Kirin Agreement, to create or incur any liens with respect to the Royalty Interest Payments, the 2017 Kyowa Kirin Agreement or certain patents, or to sell, license or transfer certain patents in the field and territory described in the 2017 Kyowa Kirin Agreement. In addition, the HCR Agreement contains customary events of default with respect to which we may incur indemnification obligations to HCR for any losses incurred by HCR and related parties as a result of the event of default, subject to a specified limitation of liability cap. Under the HCR Agreement, an event of default will occur if, among other things, any of the representations and warranties included in the HCR Agreement proves not to have been true and correct in all material respects, at the time it was made, we breach any of our covenants under the HCR Agreement, subject to specified cure periods with respect to certain breaches, we are in breach or default under the 2017 Kyowa Kirin Agreement in any manner which is likely to cause a material adverse effect on the Royalty Interest Payments, the occurrence of a termination of the 2017 Kyowa Kirin Agreement under certain circumstances or we or our assets become subject to certain legal proceedings, such as bankruptcy proceedings, or we are unable to pay our debts as they become due. We received the $10.0 million upfront payment from HCR during June 2022 and recorded it as a deferred royalty obligation related to the sale of future royalties ("deferred royalty obligation") on our balance sheet. Due to our ongoing manufacturing obligations under the 2017 Kyowa Kirin Agreement, we account for the proceeds as imputed debt and therefore will recognize royalties received under the arrangement as non-cash royalty revenue. Non-cash interest expense will be recognized over the life of the HCR Agreement using the effective interest method based on the imputed interest rate derived from estimated amounts and timing of future royalty payments to be received from Kyowa Kirin. As part of the sale, we incurred approximately $0.4 million in transaction costs, which, along with the deferred royalty obligation, are being amortized to non-cash interest expense over the estimated life of the HCR Agreement using the effective interest method. As future royalties are remitted to us by Kyowa Kirin, and subsequently from us to HCR, the balance of the deferred royalty obligation will be effectively repaid over the life of the HCR Agreement. There are a number of factors that could materially affect the fair value of the deferred royalty obligation. Such factors include, but are not limited to, the amount and timing of potential future royalty payments to be received from Kyowa Kirin under the 2017 Kyowa Kirin agreement, changing standards of care, the introduction of competing products, manufacturing or other delays, intellectual property matters, adverse events that result in governmental health authority imposed restrictions on the use of the drug products, significant changes in foreign exchange rates as the royalties remitted to HCR are made in U.S. dollars while the underlying sales of the products by Kyowa Kirin are made in Japanese yen, and other events or circumstances that could result in reduced royalty payments from Kyowa Kirin, which are not within our control, and all of which would result in a reduction of non-cash royalty revenues and the non-cash interest expense over the life of the deferred royalty obligation. We periodically assess the estimated royalty payments from Kyowa Kirin and, to the extent that the amount or timing of such payments is materially different than our original estimates, we prospectively adjust the imputed interest rate and the related amortization of the deferred royalty obligation. As of March 31, 2023, our effective interest rate used to amortize the liability is 34.4%. During the three months ended March 31, 2023, we recognized approximately $1.0 million of non-cash interest expense for the amortization of the deferred royalty obligation. As of March 31, 2023, we have received no royalty payments from Kyowa Kirin and, therefore, the deferred royalty obligation has not begun to be reduced.

Inventory (Tables)

3 Months Ended

Mar. 31, 2023

Inventory Disclosure [Abstract]

Schedule of Current Inventory

Inventory as of March 31, 2023 and December 31, 2022 consisted of the following (in thousands):


	March 31, 2023		December 31, 2022
Raw materials	$	21,702	$	22,299
Work in process	22,566		5,324
Finished goods	679		723
Total	$	44,947	$	28,346
Reported as:
Inventory	$	4,823	$	3,282
Inventory, non-current	40,124		25,064
Total	$	44,947	$	28,346

Schedule of Noncurrent Inventory

Inventory as of March 31, 2023 and December 31, 2022 consisted of the following (in thousands):


	March 31, 2023		December 31, 2022
Raw materials	$	21,702	$	22,299
Work in process	22,566		5,324
Finished goods	679		723
Total	$	44,947	$	28,346
Reported as:
Inventory	$	4,823	$	3,282
Inventory, non-current	40,124		25,064
Total	$	44,947	$	28,346

Derivative Liabilities - Narrative (Details) - USD ($) $ in Millions		1 Months Ended
	Feb. 23, 2022	Feb. 28, 2022	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	May 31, 2018
2018 Exit Fee
Derivative [Line Items]
Agreed amount for exit fee upon change of control or regulatory approval						$ 1.5
Estimated fair value			$ 1.3	$ 1.2
2018 Exit Fee \| Level 3
Derivative [Line Items]
Fair value analysis, percentage change in probability of occurrence			10.00%
Fair value analysis, effect on fair value based on 10% change in probability of occurrence			$ 0.1
2022 Exit Fee
Derivative [Line Items]
Estimated fair value			$ 0.5	$ 0.4
Exit fee (percent)		2.00%
Exit fee, net product revenue threshold	$ 100.0	$ 100.0
2022 Exit Fee \| Level 3
Derivative [Line Items]
Fair value analysis, percentage change in probability of occurrence					10.00%

CONDENSED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
CONDENSED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	Mar. 31, 2023	Mar. 31, 2022
Operating activities
Net loss	$ (26,773)	$ (28,071)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization expense	(3)	463
Non-cash lease expense	902	842
Stock-based compensation	2,912	3,722
Change in derivative liabilities	70	15
Debt refinancing costs	0	102
Gain on sale of equipment	0	(710)
Impairment of long-lived assets	429	0
Non-cash interest expense	1,044	109
Changes in operating assets and liabilities:
Accounts receivable	(4,387)	(3,892)
Inventory	(16,601)	(3,487)
Prepaid commercial manufacturing	(268)	(9,393)
Prepaid expenses and other assets	(774)	9,086
Accounts payable	(346)	753
Accrued compensation and benefits	(2,474)	882
Operating lease liabilities	(937)	(836)
Accrued and other liabilities	(1,396)	(1,041)
Deferred revenue	3,807	3,836
Net cash used in operating activities	(44,795)	(27,620)
Investing activities
Proceeds from maturities and redemptions of investments	11,000	27,300
Purchases of investments	(20,763)	(25,763)
Proceeds from sale of property and equipment	0	795
Purchases of property and equipment	(14)	0
Net cash (used in) provided by investing activities	(9,777)	2,332
Financing activities
Proceeds from 2022 Loan, net of issuance costs	0	26,971
Payments for 2018 Loan, net of costs	0	(33,038)
Proceeds from issuance of common stock in at the market offering, net of issuance costs	50,719	5,921
Proceeds from issuance of common stock under equity incentive and stock purchase plans	200	83
Net cash provided by (used in) financing activities	50,919	(63)
Net decrease in cash and cash equivalents	(3,653)	(25,351)
Cash and cash equivalents at beginning of period	96,140	72,428
Cash and cash equivalents at end of period	92,487	47,077
Supplementary disclosure of cash flow information:
Cash paid for interest	860	741
Cash paid for income taxes	0	1
Supplementary disclosure of non-cash activities:
Issuance of derivative in connection with issuance of loan payable	$ 0	$ 375

Derivative Liabilities - Changes in Fair Value (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
2018 Exit Fee
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 1,200
Ending balance	1,300
2022 Exit Fee
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	400
Ending balance	500
Exit Fee derivative liability
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	1,656	$ 698
2022 Exit Fee addition at fair value	0	375
Ending balance	1,726	1,088
Exit Fee derivative liability \| 2018 Exit Fee
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Changes in estimated fair value	48	15
Exit Fee derivative liability \| 2022 Exit Fee
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Changes in estimated fair value	$ 22	$ 0

Cash, Cash Equivalents and Investments

3 Months Ended

Mar. 31, 2023

Cash and Cash Equivalents [Abstract]

Cash, Cash Equivalents and Investments

CASH, CASH EQUIVALENTS AND INVESTMENTS

Securities classified as cash, cash equivalents and short-term investments as of March 31, 2023 and December 31, 2022 are summarized below (in thousands):


	March 31, 2023
			Gross Unrealized
	Amortized Cost		Gains		Losses		Fair Value
Cash and cash equivalents:
Cash	$	7,986	$	—	$	—	$	7,986
Money market funds	84,501		—		—		84,501


Total cash and cash equivalents	92,487		—		—		92,487
Short-term investments:
Commercial paper	$	23,353	$	3	$	(23)	$	23,333
U.S. government-sponsored agency bonds	12,618		8		(6)		12,620

Asset backed securities	1,935		—		(2)		1,933
Total short-term investments	37,906		11		(31)		37,886
Total cash, cash equivalents and investments	$	130,393	$	11	$	(31)	$	130,373


	December 31, 2022
			Gross Unrealized
	Amortized Cost		Gains		Losses		Fair Value
Cash and cash equivalents:
Cash	$	11,827	$	—	$	—	$	11,827
Money market funds	84,313		—		—		84,313


Total cash and cash equivalents	96,140		—		—		96,140
Short-term investments
Commercial paper	$	25,336	$	6	$	(51)	$	25,291
Corporate bonds	1,000		—		(1)		999
U.S. government-sponsored agency bonds	1,487		—		(8)		1,479

Total short-term investments	27,823		6		(60)		27,769


Total cash, cash equivalents and investments	$	123,963	$	6	$	(60)	$	123,909

Cash equivalents consist of money market funds with original maturities of three months or less at the time of purchase, and the carrying amount is a reasonable approximation of fair value. We invest our cash in high quality securities of financial and commercial institutions. These securities are carried at fair value, which is based on readily available market information, with unrealized gains and losses included in accumulated other comprehensive loss within stockholders’ equity on our condensed balance sheets. We use the specific identification method to determine the amount of realized gains or losses on sales of marketable securities. Realized gains or losses have been insignificant and are included in other income, net, in the statement of operations and comprehensive loss.

All of the short-term available-for sale securities held as of March 31, 2023 and December 31, 2022 had contractual maturities of less than one year. Our available-for-sale securities are subject to a periodic impairment review. We consider a debt security to be impaired when its fair value is less than its carrying cost, in which case we would further review the investment to determine whether it is other-than-temporarily impaired. When we evaluate an investment for other-than-temporary impairment, we review factors such as the length of time and extent to which fair value has been below cost basis, the financial condition of the issuer and any changes thereto, intent to sell, and whether it is more likely than not we will be required to sell the investment before the recovery of its cost basis. If an investment is other-than-temporarily impaired or subject to credit losses, we write it down through the statement of operations and comprehensive loss to its fair value and establish that value as a new cost basis for the investment. Our unrealized losses as of March 31, 2023 and December 31, 2022 were not material. We determined that none of our available-for-sale securities were other-than-temporarily impaired as of March 31, 2023 and December 31, 2022, and no investment was in a continuous unrealized loss position for more than one year. As such, we believe that it is more likely than not that the investments will be held until maturity or a forecasted recovery of fair value.

Borrowing

3 Months Ended

Mar. 31, 2023

Debt Disclosure [Abstract]

Borrowing

BORROWING

Solar Capital and Western Alliance Bank Loan Agreement

In May 2018, we entered into a loan and security agreement (as amended on October 9, 2020, March 1, 2021, May 5, 2021, and July 29, 2021) (the "2018 Loan Agreement") with Solar Capital Ltd. and Western Alliance Bank (collectively the “2018 Lenders”). The 2018 Loan Agreement provided for a loan facility for up to $50.0 million with a maturity date of November 1, 2022 (the “2018 Loan”). As of the Closing Date for the 2022 Loan, as discussed below, we owed $25.0 million in principal payments from the 2018 Loan, which we repaid in full at that time.

As discussed in Note 9. Derivative Liability, in connection with entering into the 2018 Loan Agreement, we entered into an agreement pursuant to which we agreed to pay $1.5 million in cash upon the occurrence of certain conditions (the "2018 Exit Fee"). Our obligations for the 2018 Exit Fee remain outstanding following the full repayment of the 2018 Loan in February 2022.

SLR Investment Corp. Loan Agreement

On February 23, 2022 (“Closing Date”), we entered into a loan and security agreement (“2022 Loan Agreement”) with SLR Investment Corp. as collateral agent (“Agent”), and the lenders listed in the 2022 Loan Agreement (collectively the “2022 Lenders”). The 2022 Loan Agreement was subsequently amended on August 1, 2022 and February 9, 2023. We concluded that the Loan amendments were modifications to the 2022 Loan Agreement and are accounted for accordingly. The 2022 Loan Agreement as amended provides for a senior secured loan facility, with $27.5 million (“Term A Loan”) funded on the Closing Date and an additional $22.5 million which we may borrow on or prior to December 20, 2023; provided that (i) we have received approval by the FDA for our NDA for XPHOZAH by November 30, 2023, and (ii) we have achieved certain product revenue milestone targets described in the 2022 Loan Agreement (“Term B Loan”, and collectively, the Term A Loan and the Term B Loan, the “2022 Loan”). The 2022 Term A Loan funds were used to repay the 2018 Loan with the 2018 Lenders. The 2022 Loan has a maturity date of March 1, 2027.

Borrowings under the 2022 Loan as amended bear interest at a floating per annum interest rate with 7.95% plus the greater of (a) one percent (1.00%) per annum and (b)(i) 0.022% plus (ii) 1-month CME Term SOFR reference rate as published by the CME Term SOFR Administrator on the CME Term SOFR Administrator’s Website. We are permitted to make interest-only payments on the 2022 Loan through March 31, 2024, which date will be extended to March 31, 2025 if we receive approval by the FDA for our NDA for XPHOZAH on or prior to November 30, 2023 or achieve a defined net product revenue threshold for 2023. Accordingly, beginning on April 1, 2024 or April 1, 2025, we will be required to make monthly payments of interest plus repayment of the 2022 Loan in consecutive equal monthly installments of principal over 36 months or 24 months, respectively. We were obligated to pay $0.2 million, upon the closing of the Term A Loan, and we are obligated to pay $0.1 million on the earliest of (i) the funding date of the Term B Loan, (ii) July 25, 2023, and (iii) the prepayment, refinancing, substitution, or replacement of the Term A Loan on or prior to July 25, 2023. We are obligated to pay a final fee equal to 4.95% of the aggregate original principal amount of the 2022 Loan funded upon the earliest to occur of the maturity date, the acceleration of the 2022 Loan, and the prepayment, refinancing, substitution, or replacement of the 2022 Loan. We may voluntarily prepay the outstanding 2022 Loan balance, subject to a prepayment premium of (i) 3% of the outstanding principal amount of the 2022 Loan if prepaid prior to or on the first anniversary of the Closing Date, (ii) 2% of the outstanding principal amount of the 2022 Loan if prepaid after the first anniversary of the Closing Date through and including the second anniversary of the Closing Date, or (iii) 1% of the outstanding principal amount of the 2022 Loan if prepaid after the second anniversary of the Closing Date and prior to the maturity date. The 2022 Loan is secured by substantially all of our assets, except for our intellectual property and certain other customary exclusions. Additionally, in connection with the 2022 Loan, we entered into an agreement, whereby we agreed to pay an exit fee in the amount of 2% of the 2022 Loan funded (“2022 Exit Fee”) upon (i) any change of control transaction or (ii) our achievement of net revenue from the sale of any products equal to or greater than $100.0 million, measured on a six (6) months basis, tested monthly at the end of each month. Notwithstanding the prepayment or termination of the 2022 Loan, the 2022 Exit Fee will expire 10 years from the Closing Date.

The 2022 Loan Agreement contains customary representations and warranties and customary affirmative and negative covenants, including, among others, requirements as to financial reporting and insurance and restrictions on our ability to dispose of our business or property, to change our line of business, to liquidate or dissolve, to enter into any change in control transaction, to merge or consolidate with any other entity or to acquire all or substantially all the capital stock or property of another entity, to incur additional indebtedness, to incur liens on our property, to pay any dividends or other distributions on capital stock other than dividends payable solely in capital stock or to redeem capital stock. We have agreed to not allow our cash and cash equivalents to be less than the eighty percent (80%) of the outstanding 2022 Term Loan balance for any period in which our net revenue from the sale of any products, calculated on a trailing six (6) month basis and tested monthly, is less than sixty percent (60%) of the outstanding 2022 Loan balance.

In addition, the 2022 Loan Agreement contains customary events of default that entitle the Agent to cause our indebtedness under the 2022 Loan Agreement to become immediately due and payable, and to exercise remedies against us and the collateral securing the 2022 Term Loan, including our cash. Under the 2022 Loan Agreement, an event of default will occur if, among other things, we fail to make payments under the 2022 Loan Agreement, we breach any of our covenants under the 2022 Loan Agreement, subject to specified cure periods with respect to certain breaches, certain Lenders determine that a material adverse change has occurred, we or our assets become subject to certain legal proceedings, such as bankruptcy proceedings, we are unable to pay our debts as they become due or we default on contracts with third parties which would permit the holder of indebtedness to accelerate the maturity of such indebtedness or that could have a material adverse change on us. Upon the occurrence and for the duration of an event of default, an additional default interest rate equal to 4% per annum will apply to all obligations owed under the 2022 Loan Agreement. We have classified the 2022 Loan balance as a current liability as of March 31, 2023 due to the determination of the existence of substantial doubt about our ability to continue operating as a going concern discussed in Note 1. Organization and Basis of Presentation: Liquidity and our assessment that the material adverse change clause under the 2022 Loan Agreement is not within our control. The lenders have not invoked the material adverse change clause as of the date of issuance of these condensed financial statements.


Total repayment obligations	$	28,861
Less: Unamortized discount and debt issuance costs	(1,282)
Less: Unaccreted value of final fee	(699)
Long-term debt	26,880
Less: Current portion of long-term debt	(26,880)
Long-term debt, net of current portion	$	—

- Definition

The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-URI https://asc.fasb.org/topic&trid=2208564

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
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-Paragraph 1B
-Subparagraph (h)
-URI https://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(c))
-URI https://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

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+ Details

Contingencies (Details)			4 Months Ended
Contingencies (Details)	Jul. 19, 2022 claim	Aug. 12, 2021 claim defendant	Mar. 29, 2022 claim defendant	Mar. 31, 2023 USD ($)
Contingencies [Line Items]
Contingent liabilities \| $				$ 0
Strezsak v. Ardelyx, Inc.
Contingencies [Line Items]
Number of lawsuits \| claim	2	2
Number of defendants \| defendant		2
Go v. Raab
Contingencies [Line Items]
Number of lawsuits \| claim			2
Number of defendants \| defendant			2

Equity Incentive Plans

3 Months Ended

Mar. 31, 2023

Share-Based Payment Arrangement [Abstract]

Equity Incentive Plans

EQUITY INCENTIVE PLANS

Stock-Based Compensation

Stock-based compensation expense recognized for stock options, restricted stock units ("RSUs"), and our employee stock purchase program (the "ESPP") are recorded as operating expenses in our condensed statements of operations and comprehensive loss, as follows (in thousands):


	Three Months Ended March 31,
	2023		2022
Selling, general and administrative	$	2,088	$	2,508
Research and development	824		1,214

Total	$	2,912	$	3,722

As of March 31, 2023, our total unrecognized stock-based compensation expense, net of estimated forfeitures, and average remaining vesting period, included the following (dollars in thousands):


	Unrecognized Compensation Expense		Average Remaining Vesting Period (Years)
Stock option grants	$	21,127	3.2
RSU grants	$	7,309	3.3
ESPP	$	292	0.3

Stock Options

A summary of our stock option activity and related information for the three months ended March 31, 2023 is as follows (in thousands, except dollar amounts):


	Number of Shares	Weighted-Average Exercise Price per Share
Balance at December 31, 2022	13,963	$	4.83
Options granted	6,472	$	2.78
Options exercised	(36)	$	1.65
Options forfeited or canceled	(56)	$	5.84
Balance at March 31, 2023	20,343	$	4.18
Exercisable at March 31, 2023	9,185	$	5.97

Restricted Stock Units

A summary of our RSUs activity and related information for the three months ended March 31, 2023 is as follows (in thousands, except dollar amounts):


	Number of RSUs	Weighted-Average Grant Date Fair Value Per Share
Non-vested restricted stock units at December 31, 2022	1,406	$	2.17
Granted	1,784	$	2.78
Vested	(208)	$	2.68
Forfeited	—	$	—
Non-vested restricted stock units at March 31, 2023	2,982	$	2.50

Employee Stock Purchase Plan

During the three months ended March 31, 2023, we sold approximately 0.2 million shares of our common stock under the ESPP. The shares were purchased by employees at an average purchase price of $0.83 per share resulting in proceeds to us of approximately $0.1 million.

Issuance of Common Stock for Services

Under Our Amended and Restated Non-Employee Director Compensation Program, members of our board of directors may elect to receive shares of our stock in lieu of their cash fees. During the three months ended March 31, 2023, we issued no shares of our common stock to members of the board of directors in accordance with the program.

CONDENSED BALANCE SHEETS (Parenthetical) - $ / shares	Mar. 31, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	300,000,000	300,000,000
Common stock, shares issued (in shares)	214,462,050	198,575,016
Common stock, shares outstanding (in shares)	214,462,050	198,575,016

Net Loss Per Share (Tables)

3 Months Ended

Mar. 31, 2023

Earnings Per Share [Abstract]

Schedule of Computation of Net Loss Per Common Share

The following table sets forth the computation of net loss per common share (in thousands, except per share amounts):


	Three Months Ended March 31,
Numerator:	2023		2022
Net loss	$	(26,773)	$	(28,071)
Denominator:
Weighted average common shares outstanding - basic and diluted	207,023		130,935
Net loss per share of common stock - basic and diluted	$	(0.13)	$	(0.21)

Schedule of Anti-Dilutive Securities Not Considered in Diluted Net Loss Per Common Share Calculation

For the periods presented, the total numbers of securities that could potentially dilute net income per share in the future that were not considered in the diluted net loss per share calculations because the effect would have been anti-dilutive were as follows (in thousands):


	Three Months Ended March 31,
	2023	2022
Options to purchase common stock	19,855	13,266

Restricted stock units	2,931	4,412

ESPP shares issuable	205	154
Total	22,991	17,832

Product Revenue, Net - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Disaggregation of Revenue [Line Items]
Revenue	$ 11,369	$ 468
Gross product revenue \| Customer \| Cardinal Health
Disaggregation of Revenue [Line Items]
Concentration risk (percent)		22.20%
Gross product revenue \| Customer \| AmerisourceBergen Drug Corporation
Disaggregation of Revenue [Line Items]
Concentration risk (percent)		21.60%
Gross product revenue \| Customer \| McKesson Corporation
Disaggregation of Revenue [Line Items]
Concentration risk (percent)		20.80%
IBSRELA
Disaggregation of Revenue [Line Items]
Revenue	$ 11,400	$ 500

- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (a)
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-URI https://asc.fasb.org/extlink&oid=126920106&loc=SL49130543-203045

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-Name Accounting Standards Codification
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-Paragraph 1
-Subparagraph (SAB Topic 11.L)
-URI https://asc.fasb.org/extlink&oid=6472922&loc=d3e499488-122856

+ Details

Deferred Royalty Obligation Related To The Sale Of Future Royalties (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
	Jun. 30, 2022	Mar. 31, 2023	Mar. 31, 2022
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Amortization of the deferred royalty obligation		$ 969	$ 0
Proceeds from royalties received		0
Healthcare royalty partners IV, L.P \| License
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Royalty payments and commercial milestone payments	$ 20,000
Upfront payment	10,000
Payment to be received	$ 5,000
Transaction costs		$ 400
Amortization, effective interest rate, percent		34.40%

Product Revenue, Net (Tables)

3 Months Ended

Mar. 31, 2023

Revenue from Contract with Customer [Abstract]

Schedule of Chargebacks, Discounts and Reserve Balances

The activities and ending reserve balances for each significant category of discounts and allowances, which constitute variable consideration, were as follows (in thousands):


	Discounts and Chargebacks		Rebates, Wholesaler and GPO Fees		Copay and Returns		Total
Balance as of December 31, 2022	$	142	$	1,444	$	1,258	$	2,844
Provisions	824		2,361		2,575		5,760
Credits/payments	(726)		(1,685)		(1,909)		(4,320)
Balance as of March 31, 2023	$	240	$	2,120	$	1,924	$	4,284

Equity Incentive Plans - Restricted Stock Units (Details) - Restricted stock units shares in Thousands	3 Months Ended
	Mar. 31, 2023 $ / shares shares
Number of RSUs
Outstanding balance, beginning (in shares) \| shares	1,406
Granted (in shares) \| shares	1,784
Vested (in shares) \| shares	(208)
Forfeited (in shares) \| shares	0
Outstanding balance, ending (in shares) \| shares	2,982
Weighted-Average Grant Date Fair Value Per Share
Outstanding balance, beginning (in dollars per share) \| $ / shares	$ 2.17
Granted (in dollars per share) \| $ / shares	2.78
Vested (in dollars per share) \| $ / shares	2.68
Forfeited (in dollars per share) \| $ / shares	0
Outstanding balance, ending (in dollars per share) \| $ / shares	$ 2.50

Net Loss Per Share

3 Months Ended

Mar. 31, 2023

Earnings Per Share [Abstract]

Net Loss Per Share

NET LOSS PER SHARE

Basic net loss per share is calculated by dividing net loss by the weighted-average number of common shares outstanding during the period, less shares subject to repurchase, and excludes any dilutive effects of stock-based awards and warrants. Diluted net loss per common share is computed giving effect to all potential dilutive common shares, including common stock issuable upon exercise of stock options, and unvested restricted common stock and stock units. As we had net losses for the three months ended March 31, 2023 and 2022, all potential common shares were determined to be anti-dilutive.

The following table sets forth the computation of net loss per common share (in thousands, except per share amounts):


	Three Months Ended March 31,
Numerator:	2023		2022
Net loss	$	(26,773)	$	(28,071)
Denominator:
Weighted average common shares outstanding - basic and diluted	207,023		130,935
Net loss per share of common stock - basic and diluted	$	(0.13)	$	(0.21)


	Three Months Ended March 31,
	2023	2022
Options to purchase common stock	19,855	13,266

Restricted stock units	2,931	4,412

ESPP shares issuable	205	154
Total	22,991	17,832

Product Revenue, Net

3 Months Ended

Mar. 31, 2023

Revenue from Contract with Customer [Abstract]

Product Revenue, Net

PRODUCT REVENUE, NET

We received approval from the FDA in September 2019 to market IBSRELA in the U.S. We began selling IBSRELA in the U.S. in March 2022. We recorded net revenue for IBSRELA of $11.4 million and $0.5 million during the three months ended March 31, 2023 and 2022, respectively. We distribute IBSRELA principally through major wholesalers, specialty pharmacies and group purchasing organizations ("GPOs") (collectively, our "Customers"). Our Customers subsequently sell IBSRELA to pharmacies and patients. Separately, we enter into arrangements with third parties that provide for government-mandated rebates, chargebacks and discounts. Revenue from product sales is recognized when our performance obligations are satisfied, which is when Customers obtain control of our product and occurs upon delivery.

Sales to Cardinal Health, AmerisourceBergen Drug Corporation, and McKesson Corporation made up 22.2%, 21.6%, and 20.8%, respectively, of our product sales, net during the three months ended March 31, 2023.

The activities and ending reserve balances for each significant category of discounts and allowances, which constitute variable consideration, were as follows (in thousands):


	Discounts and Chargebacks		Rebates, Wholesaler and GPO Fees		Copay and Returns		Total
Balance as of December 31, 2022	$	142	$	1,444	$	1,258	$	2,844
Provisions	824		2,361		2,575		5,760
Credits/payments	(726)		(1,685)		(1,909)		(4,320)
Balance as of March 31, 2023	$	240	$	2,120	$	1,924	$	4,284

- 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
-Publisher FASB
-Name Accounting Standards Codification
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+ Details

Equity Incentive Plans - Stock Options (Details)	3 Months Ended
Equity Incentive Plans - Stock Options (Details)	Mar. 31, 2023 $ / shares shares
Number of Shares
Options outstanding balance, beginning (in shares) \| shares	13,963,000
Options granted (in shares) \| shares	6,472,000
Options exercised (in shares) \| shares	(36,000)
Options forfeited or canceled (in shares) \| shares	(56,000)
Options outstanding balance, ending (in shares) \| shares	20,343,000
Options exercisable (in shares) \| shares	9,185,000
Weighted-Average Exercise Price per Share
Options outstanding balance, beginning (in dollars per share) \| $ / shares	$ 4.83
Options granted (in dollars per share) \| $ / shares	2.78
Options exercised (in dollars per share) \| $ / shares	1.65
Options forfeited or canceled (in dollars per share) \| $ / shares	5.84
Options outstanding balance, ending (in dollars per share) \| $ / shares	4.18
Options exercisable (in dollars per share) \| $ / shares	$ 5.97

Organization and Basis of Presentation (Policies)

3 Months Ended

Mar. 31, 2023

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Basis of Presentation

These condensed financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and pursuant to the requirements of the Securities and Exchange Commission (“SEC”) for interim reporting. As permitted under those rules and regulations, certain footnotes or other financial information that are normally required by U.S. GAAP have been condensed or omitted. These condensed financial statements have been prepared on the same basis as our most recent annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments necessary to present fairly our financial position, results of operations, changes in stockholders’ equity, and cash flows for the interim periods presented.

The accompanying condensed financial statements and related financial information should be read in conjunction with the audited financial statements and the related notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2022. The results for the three months ended March 31, 2023 are not necessarily indicative of results to be expected for the entire year ending December 31, 2023, or for any other interim period or future year.

Use of Estimates

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and judgments that affect the amounts reported in the financial statements and accompanying notes thereto. On an ongoing basis, management evaluates its estimates, including those related to recognition of revenue, clinical trial accruals, contract manufacturing accruals, utilization of inventory, fair value of assets and liabilities, income taxes and stock-based compensation. Management bases its estimates on historical experience and on various other market-specific and relevant assumptions that management believes to be reasonable under the circumstances. Actual results could materially differ from those estimates.

Recent Accounting Pronouncements

New Accounting Pronouncements - Recently Adopted

We have adopted no new accounting pronouncements subsequent to filing our most recent Annual Report on Form 10-K.

Recent Accounting Pronouncements Not Yet Adopted

There were various accounting standards and interpretations issued recently, none of which are expected to have a material impact on our financial position, operations or cash flows.

Fair Value Measurements

The three-level hierarchy for the inputs to valuation techniques is briefly summarized as follows:


Level 1 –			Valuations are based on quoted prices in active markets for identical assets or liabilities and readily accessible by us at the reporting date.

Level 2 –			Valuations based on inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

Level 3 –			Valuations based on unobservable inputs for which there is little or no market data, which require us to develop our own assumptions.

Note 9. Derivative Liabilities, are classified as Level 3.

The carrying amounts reflected in the condensed balance sheets for cash equivalents, short-term investments, accounts receivable, prepaid expenses and other current assets, accounts payable and accrued expenses approximate their fair values at both March 31, 2023 and December 31, 2022, due to their short-term nature.

Based on our procedures under the expected credit loss model, including an assessment of unrealized losses in our portfolio, we concluded that any unrealized losses on our marketable securities were not attributable to credit and, therefore, we have not recorded an allowance for credit losses for these securities as of March 31, 2023 and December 31, 2022.

Fair Value of Debt

The principal amount outstanding under our term loan facilities is subject to a variable interest rate. Therefore, we believe the carrying amount of the term loan facility approximates fair value as of March 31, 2023 and December 31, 2022. See Note 8. Borrowing for a description of the Level 2 inputs used to estimate the fair value of the liability.

The carrying value of the deferred royalty obligation related to the sale of future royalties approximates its fair value as of March 31, 2023 and December 31, 2022 and is based on our current estimates of future royalties and commercialization milestones expected to be paid to us by Kyowa Kirin Co., Ltd. ("Kyowa Kirin") over the life of the agreement. See Note 7. Deferred Royalty Obligation Related to the Sale of Future Royalties for a description of the Level 3 inputs used to estimate the fair value of the liability.

Equity Incentive Plans (Tables)

3 Months Ended

Mar. 31, 2023

Share-Based Payment Arrangement [Abstract]

Summary of Stock-Based Compensation Expense Recognized


	Three Months Ended March 31,
	2023		2022
Selling, general and administrative	$	2,088	$	2,508
Research and development	824		1,214

Total	$	2,912	$	3,722

Summary of Total Unrecognized Stock-Based Compensation Expense, Net of Estimated Forfeitures

As of March 31, 2023, our total unrecognized stock-based compensation expense, net of estimated forfeitures, and average remaining vesting period, included the following (dollars in thousands):


	Unrecognized Compensation Expense		Average Remaining Vesting Period (Years)
Stock option grants	$	21,127	3.2
RSU grants	$	7,309	3.3
ESPP	$	292	0.3

Schedule of Stock Option Activity

A summary of our stock option activity and related information for the three months ended March 31, 2023 is as follows (in thousands, except dollar amounts):


	Number of Shares	Weighted-Average Exercise Price per Share
Balance at December 31, 2022	13,963	$	4.83
Options granted	6,472	$	2.78
Options exercised	(36)	$	1.65
Options forfeited or canceled	(56)	$	5.84
Balance at March 31, 2023	20,343	$	4.18
Exercisable at March 31, 2023	9,185	$	5.97

Schedule of Restricted Stock Units Activity

A summary of our RSUs activity and related information for the three months ended March 31, 2023 is as follows (in thousands, except dollar amounts):


	Number of RSUs	Weighted-Average Grant Date Fair Value Per Share
Non-vested restricted stock units at December 31, 2022	1,406	$	2.17
Granted	1,784	$	2.78
Vested	(208)	$	2.68
Forfeited	—	$	—
Non-vested restricted stock units at March 31, 2023	2,982	$	2.50

Cash, Cash Equivalents and Investments - Securities Classified as Cash, Cash Equivalents and Investments (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Cash and cash equivalents:
Fair Value	$ 92,487	$ 96,140
Short-term investments:
Amortized Cost	37,906	27,823
Gross Unrealized Gains	11	6
Gross Unrealized Losses	(31)	(60)
Fair Value	37,886	27,769
Long-term investments:
Total cash equivalents and investments, Cost	130,393	123,963
Total cash equivalents and investments, Gross Unrealized Gains	11	6
Total cash equivalents and investments, Gross Unrealized Losses	(31)	(60)
Total cash equivalents and investments, Fair Value	130,373	123,909
Commercial paper
Short-term investments:
Amortized Cost	23,353	25,336
Gross Unrealized Gains	3	6
Gross Unrealized Losses	(23)	(51)
Fair Value	23,333	25,291
U.S. government-sponsored agency bonds
Short-term investments:
Amortized Cost	12,618	1,487
Gross Unrealized Gains	8	0
Gross Unrealized Losses	(6)	(8)
Fair Value	12,620	1,479
Corporate bonds
Short-term investments:
Amortized Cost		1,000
Gross Unrealized Gains		0
Gross Unrealized Losses		(1)
Fair Value		999
Asset backed securities
Short-term investments:
Amortized Cost	1,935
Gross Unrealized Gains	0
Gross Unrealized Losses	(2)
Fair Value	1,933
Cash
Cash and cash equivalents:
Fair Value	7,986	11,827
Money market funds
Cash and cash equivalents:
Fair Value	$ 84,501	$ 84,313

Leases - Lease Costs (Details) - USD ($) $ in Thousands	3 Months Ended
Leases - Lease Costs (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Mar. 31, 2022
Lease costs
Operating lease expense	$ 1,064	$ 1,064
Cash paid for operating lease	$ 1,098	$ 1,058

Fair Value Measurements - Narrative (Details) - USD ($)	Mar. 31, 2023	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Allowance for credit loss on available for-sale debt securities	$ 0	$ 0

Collaboration and Licensing Agreements

3 Months Ended

Mar. 31, 2023

Collaboration and Licensing Agreements

Collaboration and Licensing Agreements

COLLABORATION AND LICENSING AGREEMENTS

Kyowa Kirin Co., Ltd. (“Kyowa Kirin”)

In November 2017, we entered into an exclusive license agreement with Kyowa Kirin (“2017 Kyowa Kirin Agreement”), under which we granted Kyowa Kirin an exclusive license to develop and commercialize certain NHE3 inhibitors including tenapanor in Japan for the treatment of cardiorenal diseases and conditions, excluding cancer. We retained the rights to tenapanor outside of Japan, and also retained the rights to tenapanor in Japan for indications other than those stated above. Pursuant to the 2017 Kyowa Kirin Agreement, Kyowa Kirin is responsible for all costs and expenses incurred in the development and commercialization of tenapanor for all licensed indications in Japan. We are responsible for supplying the tenapanor drug substance for Kyowa Kirin’s use in development and commercialization throughout the term of the 2017 Kyowa Kirin Agreement, provided that Kyowa Kirin may exercise an option to manufacture the tenapanor drug substance under certain conditions. In October 2022, we entered into a Commercial Supply Agreement with Kyowa Kirin to further define the obligations of the parties with respect to the commercial supply of tenapanor drug substance (“2022 Kyowa Kirin Supply Agreement”). As detailed below under the heading “Deferred revenue’ we have received advanced payments from Kyowa Kirin for the manufacturing of tenapanor drug substance that will be used to satisfy Kyowa Kirin needs.

We assessed these arrangements in accordance with Accounting Standards Update (“ASU”) No. 2014-09, Revenue from Contracts with Customers (Topic 606) and related amendments (“ASC 606”) and concluded that the contract counterparty, Kyowa Kirin, is a customer. Under the terms of the 2017 Kyowa Kirin Agreement, we received $30.0 million in upfront license fees, which was recognized as revenue when the agreement was executed. Based on our assessment, management determined that the license and the manufacturing supply services were its material performance obligations at the inception of the 2017 Kyowa Kirin Agreement, and as such, each of the performance obligations is distinct.

Under the terms of the 2017 Kyowa Kirin Agreement, Kyowa Kirin paid us an up-front license fee of $30.0 million. We may be entitled to receive up to $55.0 million in total development and regulatory milestones, of which $20.0 million has been received and recognized as revenue as of March 31, 2023. We may also be eligible to receive approximately ¥8.5 billion for commercialization milestones, or approximately $64.1 million at the currency exchange rate on March 31, 2023, as well as reimbursement of costs plus a reasonable overhead for the supply of product and royalties on net sales throughout the term of the agreement. As discussed in Note 7. Deferred Royalty Obligation Related to the Sale of Future Royalties, the future royalties and commercial milestone payments we may receive under the 2017 Kyowa Kirin Agreement will be remitted to HealthCare Royalty Partners IV, L.P. pursuant to a Royalty and Sales Milestone Interest Acquisition Agreement. The variable consideration related to the remaining milestone payments was fully constrained at March 31, 2023.

In April 2022, we entered into a second amendment to the 2017 Kyowa Kirin Agreement ("2022 Amendment"). Under the terms of the 2022 Amendment, we and Kyowa Kirin have agreed to a reduction in the royalty rate payable to us by Kyowa Kirin upon net sales of tenapanor for hyperphosphatemia in Japan. The royalty rate will be reduced from the high teens to low double digits for a two-year period of time following the first commercial sale in Japan, and then to mid-single digits for the remainder of the royalty term. As discussed in Note 7. Deferred Royalty Obligation Related to the Sale of Future Royalties, the future commercial milestones and royalties we may receive under the 2017 Kyowa Kirin Agreement will be remitted to HealthCare Royalty Partners IV, L.P. pursuant to a Royalty and Sales Milestone Interest Acquisition Agreement. As consideration for the reduction in the royalty rate, Kyowa Kirin agreed to pay us up to an additional $40.0 million payable in two tranches, with the first payment due following Kyowa Kirin's filing with the Japanese Ministry of Health, Labour and Welfare of its application for marketing approval for tenapanor and the second payment due following Kyowa Kirin’s receipt of regulatory approval to market tenapanor for hyperphosphatemia in Japan.

In October 2022, we announced that Kyowa Kirin submitted an NDA to the Japanese Ministry of Health, Labour and Welfare for tenapanor for the improvement of hyperphosphatemia in adult patients with CKD on dialysis, which resulted in payment to us from Kyowa Kirin for an aggregate of $35.0 million for milestone payments and payments under the 2022 Amendment. We received these payments during the fourth quarter of 2022 and recorded them as licensing revenue on our statement of operations and comprehensive loss. The remaining variable consideration related to the reduction in the royalty rate was fully constrained at March 31, 2023.

During the three months ended March 31, 2023 and 2022, we did not recognize a material amount of revenue pursuant to the 2017 Kyowa Kirin Agreement.

Shanghai Fosun Pharmaceutical Industrial Development Co. Ltd. (“Fosun Pharma”)

In December 2017, we entered into an exclusive license agreement with Fosun Pharma ("Fosun Agreement") for the development, commercialization and distribution of tenapanor in China for both hyperphosphatemia and IBS-C. We assessed these arrangements in accordance with ASC 606 and concluded that the contract counterparty, Fosun Pharma, is a customer. Under the terms of the Fosun Agreement, we received $12.0 million in up-front license fees which was recognized as revenue when the agreement was executed. Based on our assessment, we determined that the license and the manufacturing supply services represented the material performance obligations at the inception of the agreement and, as such, each of the performance obligations are distinct.

We may be entitled to receive development and commercialization milestones of up to $110.0 million, of which $3.0 million has been received and recognized as revenue as of March 31, 2023, as well as reimbursement of cost plus a reasonable overhead for the supply of product and tiered royalties on net sales ranging from the mid-teens to 20%. The variable consideration related to the remaining development milestone payments was fully constrained at March 31, 2023.

During the three months ended March 31, 2023 and 2022, we did not recognize a material amount of revenue pursuant to the Fosun Agreement.

Knight Therapeutics, Inc. (“Knight“)

In March 2018, we entered into an exclusive license agreement with Knight Therapeutics, Inc., ("Knight Agreement") for the development, commercialization and distribution of tenapanor in Canada for hyperphosphatemia and IBS-C. We assessed this arrangement in accordance with ASC 606 and concluded that the contract counterparty, Knight, is a customer. Based on our assessment, we determined that the license and the manufacturing supply services were the material performance obligations at the inception of the agreement and, as such, each of the performance obligations are distinct.

Under the terms of the Knight Agreement, we received a $2.3 million non-refundable, one-time upfront payment in March 2018 and may be eligible to receive additional development and commercialization milestone payments worth up to CAD 22.2 million, or approximately $16.3 million at the currency exchange rate on March 31, 2023, of which $0.7 million has been received and recognized as revenue as of March 31, 2023. We are also eligible to receive royalties ranging from the mid-single digits to the low twenties throughout the term of the agreement, and a transfer price for manufacturing services. The variable consideration related to the remaining development milestone payments was fully constrained at March 31, 2023.

During the three months ended March 31, 2023 and 2022, we did not recognize a material amount of revenue pursuant to the Knight Agreement.

AstraZeneca AB (“AstraZeneca”)

In June 2015, we entered into a termination agreement with AstraZeneca (the “AstraZeneca Termination Agreement”) pursuant to which we have agreed to pay AstraZeneca (i) future royalties at a royalty rate of 10% of net sales of tenapanor or other NHE3 products by us or our licensees, and (ii) 20% of non-royalty revenue received from a new collaboration partner should we elect to license, or otherwise provide rights to develop and commercialize tenapanor or other NHE3 products, up to a maximum of $75.0 million in aggregate for (i) and (ii). As of March 31, 2023, to date in aggregate, we have recognized $16.4 million of the $75.0 million, which has been recorded as cost of revenue, and have paid AstraZeneca $11.9 million. During the three months ended March 31, 2023, we recognized and recorded $1.2 million as cost of revenue related to the AstraZeneca Termination Agreement. During the three months ended March 31, 2022 we recognized $0.1 million as cost of revenue related to the AstraZeneca Termination Agreement.

Deferred Revenue

The following tables present changes in our current and non-current deferred revenue balances during the reporting period, which are all attributable to the 2017 Kyowa Kirin Agreement (in thousands):


Deferred revenue - current	2023		2022
Balance at January 1,	$	4,211	$	—

Increases due to amounts reclassified from non-current, to be recognized in the next twelve months	809
Increases to amounts invoiced, for which cash has not yet been received	525		—



Balance at March 31,	$	5,545	$	—


Deferred revenue - non-current	2023		2022
Balance at January 1,	$	9,025	$	4,727

Increases to amounts invoiced, for which cash has not yet been received	3,282		3,829
Increase due to unbilled prepayments recorded during the period	—		7
Decreases due to amounts reclassified as current, to be recognized in the next twelve months	(809)		—

Balance at March 31,	$	11,498	$	8,563

Inventory - Schedule (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Inventory Disclosure [Abstract]
Raw materials	$ 21,702	$ 22,299
Work in process	22,566	5,324
Finished goods	679	723
Inventory	4,823	3,282
Inventory, non-current	40,124	25,064
Total	$ 44,947	$ 28,346

Fair Value Measurements

3 Months Ended

Mar. 31, 2023

Fair Value Disclosures [Abstract]

Fair Value Measurements

FAIR VALUE MEASUREMENTS

Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs.

The three-level hierarchy for the inputs to valuation techniques is briefly summarized as follows:


Level 1 –			Valuations are based on quoted prices in active markets for identical assets or liabilities and readily accessible by us at the reporting date.

Level 2 –			Valuations based on inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

Level 3 –			Valuations based on unobservable inputs for which there is little or no market data, which require us to develop our own assumptions.

The following table sets forth the fair value of our financial assets and liabilities that are measured or disclosed on a recurring basis by level within the fair value hierarchy (in thousands):


	March 31, 2023
	Total Fair Value		Level 1		Level 2		Level 3
Assets:
Money market funds	$	84,501	$	84,501	$	—	$	—
Commercial paper	23,333		—		23,333		—
U.S. government-sponsored agency bonds	12,620		—		12,620		—

Asset-backed securities	1,933		—		1,933		—

Total	$	122,387	$	84,501	$	37,886	$	—

Liabilities:
Derivative liabilities for exit fees	$	1,726	$	—	$	—	$	1,726
Total	$	1,726	$	—	$	—	$	1,726


	December 31, 2022
	Total Fair Value		Level 1		Level 2		Level 3
Assets:
Money market funds	$	84,313	$	84,313	$	—	$	—
Commercial paper	25,291		—		25,291		—
Corporate bonds	999		—		999		—
U.S. government-sponsored agency bonds	1,479		—		1,479		—


Total	$	112,082	$	84,313	$	27,769	$	—

Liabilities:
Derivative liability for exit fee	$	1,656	$	—	$	—	$	1,656
Total	$	1,656	$	—	$	—	$	1,656

Where quoted prices are available in an active market, securities are classified as Level 1. We classify money market funds as Level 1. When quoted market prices are not available for the specific security, we estimate fair value by using benchmark yields, reported trades, broker/dealer quotes and issuer spreads. We classify U.S. government-sponsored agency bonds, U.S. treasury notes, corporate bonds, commercial paper, and asset-backed securities as Level 2. In certain cases, where there is limited activity or less transparency around inputs to valuation, securities or derivative liabilities, such as the 2018 Exit Fee and the 2022 Exit Fee, as defined and discussed in Note 9. Derivative Liabilities, are classified as Level 3.

Fair Value of Debt

- 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

Collaboration and Licensing Agreements (Tables)

3 Months Ended

Mar. 31, 2023

Collaboration and Licensing Agreements

Schedule of Deferred Revenue Balances

The following tables present changes in our current and non-current deferred revenue balances during the reporting period, which are all attributable to the 2017 Kyowa Kirin Agreement (in thousands):


Deferred revenue - current	2023		2022
Balance at January 1,	$	4,211	$	—

Increases due to amounts reclassified from non-current, to be recognized in the next twelve months	809
Increases to amounts invoiced, for which cash has not yet been received	525		—



Balance at March 31,	$	5,545	$	—


Deferred revenue - non-current	2023		2022
Balance at January 1,	$	9,025	$	4,727

Increases to amounts invoiced, for which cash has not yet been received	3,282		3,829
Increase due to unbilled prepayments recorded during the period	—		7
Decreases due to amounts reclassified as current, to be recognized in the next twelve months	(809)		—

Balance at March 31,	$	11,498	$	8,563

Borrowing - Narrative (Details) - USD ($)		1 Months Ended
Borrowing - Narrative (Details) - USD ($)	Feb. 23, 2022	Feb. 28, 2022	Mar. 31, 2023	May 31, 2018
Debt Instrument [Line Items]
Principal outstanding			$ 28,861,000
2018 Term Loan \| Loan Agreement
Debt Instrument [Line Items]
Term loan face amount				$ 50,000,000
Principal outstanding				25,000,000
2022 Term Loan \| Loan Agreement
Debt Instrument [Line Items]
Final fee due upon maturity, acceleration, prepayment, or termination (percent)	4.95%
Loan agreement covenant, cash and cash equivalents as percentage of outstanding loan balance, minimum	80.00%
Loan agreement, covenant, cash and cash equivalents as percentage of outstanding loan balance, calculation period	6 months
Loan agreement covenant, net product revenue as percentage of outstanding loan balance, minimum	60.00%
Additional default interest rate	4.00%
2022 Term Loan \| Loan Agreement \| SOFR
Debt Instrument [Line Items]
Floating per annum rate (percent)	7.95%
2022 Term Loan \| Loan Agreement \| Prior to first anniversary of closing date
Debt Instrument [Line Items]
Prepayment premium (as a percent)	3.00%
2022 Term Loan \| Loan Agreement \| After first anniversary through second anniversary of closing date
Debt Instrument [Line Items]
Prepayment premium (as a percent)	2.00%
2022 Term Loan \| Loan Agreement \| After second anniversary to maturity date
Debt Instrument [Line Items]
Prepayment premium (as a percent)	1.00%
Term Loan A \| Loan Agreement
Debt Instrument [Line Items]
Proceeds from the sale of future royalties, net of issuance costs	$ 27,500,000
Payment term	36 months
Closing fee	$ 200,000
Term Loan B \| Loan Agreement
Debt Instrument [Line Items]
Remaining funding based on milestone achievement	$ 22,500,000
Payment term	24 months
Future obligation upon loan funding or other events	$ 100,000
Term B Loan \| Loan Agreement \| SOFR
Debt Instrument [Line Items]
Addition to floating per annum rate (percent)	1.00%
Addition plus to floating per annum rate (percent)	0.022%
2018 Exit Fee
Debt Instrument [Line Items]
Agreed amount for exit fee upon occurrence of certain conditions				$ 1,500,000
2022 Exit Fee
Debt Instrument [Line Items]
Exit fee (percent)		2.00%
Exit fee, net product revenue threshold	$ 100,000,000	$ 100,000,000
Exit fee, term (in years)	10 years

Contingencies	3 Months Ended
Contingencies	Mar. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Contingencies	CONTINGENCIES On July 30 and August 12, 2021, two putative securities class action lawsuits were commenced in the U.S. District Court for the Northern District of California naming as defendants Ardelyx and two current officers captioned Strezsak v. Ardelyx, Inc., et al., Case No. 4:21-cv-05868-HSG, and Siegel v. Ardelyx, Inc., et al., Case No. 5:21-cv-06228-HSG (together, the “Securities Class Actions”). The complaints allege that the defendants violated Sections 10(b) and 20(a) of the Securities Exchange Act of 1934, as amended, and Rule 10b-5 thereunder, by making false and misleading statements and omissions of material fact related to tenapanor. The plaintiffs seek damages and interest, and an award of costs, including attorneys’ fees. On July 19, 2022, the court consolidated the two putative class actions and appointed a lead plaintiff and lead counsel. The lead plaintiff filed an amended complaint on September 29, 2022. Defendants filed a motion to dismiss the amended complaint on December 2, 2022. In January and February 2023, in lieu of filing a response to defendant’s motion to dismiss, plaintiffs filed a motion seeking leave to further amend their complaint and defendants filed an opposition to the motion for leave to further amend the complaint. On April 6, 2023, the court granted plaintiff’s motion for leave to further amend the complaint. With the second amended complaint, the plaintiffs seek to represent all persons who purchased or otherwise acquired Ardelyx securities between March 6, 2020 and July 19, 2021. The parties have stipulated to a schedule for the filing of Defendants second motion to dismiss on June 2, 2023, and a hearing on the motion to dismiss to held on September 14, 2023. We believe the plaintiff’s claims are without merit and we have not recorded any accrual for a contingent liability associated with these legal proceedings. On December 7, 2021 and March 29, 2022, two verified shareholders derivative lawsuits were filed in the U.S. District Court for the Northern District of California purportedly on behalf of Ardelyx against certain of Ardelyx’s executive officers and members of our board of directors, captioned Go v. Raab, et al., Case No. 4:21-cv-09455-HSG, and Morris v. Raab, et al., Case No. 4:22-cv-01988-JSC. The complaints allege that the defendants violations of Section 14(a) of the Securities Exchange Act of 1934, as amended, breaches of fiduciary duties, unjust enrichment, abuse of control, gross mismanagement, and waste of corporate assets, for personally making and/or causing Ardelyx to make materially false and misleading statements regarding the Company’s business, operations and prospects. The complaint seeks contribution under Sections 10(b) and 21D of the Securities Exchange Act of 1934 from two executive officers. On January 19, and April 27, 2022, the court granted the parties’ stipulation to stay the Go and Morris actions, respectively, until resolution of the anticipated motion(s) to dismiss in the Securities Class Actions. On October 25, 2022, the parties filed a stipulation to consolidate and stay the Go and Morris actions, and on October 27, 2022, the court consolidated the Go and Morris action and stayed the consolidated action pending resolution of the anticipated motion(s) to dismiss in the Securities Class Action. We believe the plaintiff’s claims are without merit and we have not recorded any accrual for a contingent liability associated with these legal proceedings. From time to time, we may be involved in legal proceedings arising in the ordinary course of business. As of March 31, 2023, there is no litigation pending that would reasonably be expected to have a material adverse effect on our results of operations and financial condition, and no contingent liabilities were accrued as of March 31, 2023.

Net Loss Per Share - Anti Dilutive Securities Excluded from Computation of Diluted Net Loss Per Share (Details) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	22,991	17,832
Options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	19,855	13,266
Restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	2,931	4,412
ESPP shares issuable
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	205	154

Leases - Narrative (Details) - Facility, Fremont California $ in Millions	3 Months Ended
	Mar. 31, 2023 USD ($) ft²
Lessee, Lease, Description [Line Items]
Operating lease, impairment loss \| $	$ 0.4
Minimum
Lessee, Lease, Description [Line Items]
Office space area (sq ft)	21,644
Maximum
Lessee, Lease, Description [Line Items]
Office space area (sq ft)	72,500