0001628280-22-021047 | 10-Q | XBRL Viewer

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Cover - shares	6 Months Ended
Cover - shares	Jun. 30, 2022	Jul. 31, 2022
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2022
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	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		154,635,575
Entity Central Index Key	0001437402
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q2
Amendment Flag	false

CONDENSED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 53,408	$ 72,428
Short-term investments	27,604	44,261
Accounts receivable	5,623	502
Inventory	4,529	0
Prepaid commercial manufacturing	17,793	9,406
Prepaid expenses and other current assets	5,150	7,052
Total current assets	114,107	133,649
Right-of-use assets	11,054	12,752
Property and equipment, net	1,541	2,362
Other assets	4,908	1,150
Total assets	131,610	149,913
Current liabilities:
Accounts payable	4,294	4,277
Accrued compensation and benefits	6,405	5,422
Current portion of long-term debt	26,373	32,264
Current portion of operating lease liability	3,691	3,492
Accrued expenses and other current liabilities	7,936	7,366
Total current liabilities	48,699	52,821
Operating lease liability, net of current portion	7,857	9,748
Deferred revenue, non-current	12,421	4,727
Deferred royalty obligation	9,591	0
Total liabilities	78,568	67,296
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 June 30, 2022 and December 31, 2021, respectively.	0	0
Common stock, $0.0001 par value; 300,000,000 shares authorized; 153,797,834 and 130,182,535 shares issued and outstanding as of June 30, 2022 and December 31, 2021, respectively.	15	13
Additional paid-in capital	821,075	795,540
Accumulated deficit	(767,939)	(712,930)
Accumulated other comprehensive loss	(109)	(6)
Total stockholders’ equity	53,042	82,617
Total liabilities and stockholders’ equity	$ 131,610	$ 149,913

CONDENSED BALANCE SHEETS (Parenthetical) - $ / shares	Jun. 30, 2022	Dec. 31, 2021
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)	153,797,834	130,182,535
Common stock, shares outstanding (in shares)	153,797,834	130,182,535

CONDENSED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Revenues:
Total revenues	$ 2,526,000	$ 1,313,000	$ 2,994,000	$ 7,895,000
Operating expenses:
Cost of revenue	138,000	0	223,000	1,000,000
Research and development	9,741,000	26,021,000	18,592,000	46,477,000
Selling, general and administrative	18,862,000	20,124,000	38,201,000	37,255,000
Total operating expenses	28,741,000	46,145,000	57,016,000	84,732,000
Loss from operations	(26,215,000)	(44,832,000)	(54,022,000)	(76,837,000)
Interest expense	(787,000)	(1,202,000)	(1,533,000)	(2,302,000)
Other income, net	70,000	847,000	554,000	798,000
Loss before provision for income taxes	(26,932,000)	(45,187,000)	(55,001,000)	(78,341,000)
Provision for income taxes	6,000	2,000	8,000	3,000
Net loss	$ (26,938,000)	$ (45,189,000)	$ (55,009,000)	$ (78,344,000)
Net loss per common share - basic (in dollars per share)	$ (0.19)	$ (0.45)	$ (0.40)	$ (0.79)
Net loss per common share - diluted (in dollars per share)	$ (0.19)	$ (0.45)	$ (0.40)	$ (0.79)
Shares used in computing net loss per share - basic (in shares)	145,544,372	100,040,083	138,279,945	98,617,564
Shares used in computing net loss per share - diluted (in shares)	145,544,372	100,040,083	138,279,945	98,617,564
Comprehensive loss:
Net loss	$ (26,938,000)	$ (45,189,000)	$ (55,009,000)	$ (78,344,000)
Unrealized losses on available-for-sale securities	(21,000)	11,000	(103,000)	8,000
Comprehensive loss	(26,959,000)	(45,178,000)	(55,112,000)	(78,336,000)
Product sales, net
Revenues:
Total revenues	1,564,000	0	2,014,000	0
Product Supply Revenue
Revenues:
Total revenues	952,000	0	966,000	126,000
License
Revenues:
Total revenues	10,000	3,000	14,000	5,005,000
Collaborative development revenue
Revenues:
Total revenues	$ 0	$ 1,310,000	$ 0	$ 2,764,000

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, 2020		93,599,975
Beginning balance at Dec. 31, 2020	$ 126,112	$ 9	$ 680,872	$ (554,765)	$ (4)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under employee stock purchase plan (in shares)		102,208
Issuance of common stock under employee stock purchase plan	478		478
Issuance of common stock upon exercise of options (in shares)		205,306
Issuance of common stock upon exercise of options	563		563
Issuance of common stock upon vesting of restricted stock units (in shares)		79,784
Issuance of common stock in at the market offering (in shares)		8,979,744
Issuance of common stock in at the market offering	62,446	$ 1	62,445
Stock-based compensation	6,306		6,306
Unrealized (losses) gains on available-for-sale securities	8				8
Net loss	(78,344)			(78,344)
Ending balance (in shares) at Jun. 30, 2021		102,967,017
Ending balance at Jun. 30, 2021	117,569	$ 10	750,664	(633,109)	4
Beginning balance (in shares) at Mar. 31, 2021		98,688,577
Beginning balance at Mar. 31, 2021	130,811	$ 10	718,728	(587,920)	(7)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of options (in shares)		194,799
Issuance of common stock upon exercise of options	543		543
Issuance of common stock upon vesting of restricted stock units (in shares)		44,684
Issuance of common stock in at the market offering (in shares)		4,038,957
Issuance of common stock in at the market offering	28,174		28,174
Stock-based compensation	3,219		3,219
Unrealized (losses) gains on available-for-sale securities	11				11
Net loss	(45,189)			(45,189)
Ending balance (in shares) at Jun. 30, 2021		102,967,017
Ending balance at Jun. 30, 2021	117,569	$ 10	750,664	(633,109)	4
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 exercise of options (in shares)	0
Issuance of common stock upon vesting of restricted stock units (in shares)		2,996,142
Issuance of common stock in at the market offering (in shares)		20,492,057
Issuance of common stock in at the market offering	$ 18,478	$ 2	18,476
Stock-based compensation	6,976		6,976
Unrealized (losses) gains on available-for-sale securities	(103)				(103)
Net loss	(55,009)			(55,009)
Ending balance (in shares) at Jun. 30, 2022		153,797,834
Ending balance at Jun. 30, 2022	53,042	$ 15	821,075	(767,939)	(109)
Beginning balance (in shares) at Mar. 31, 2022		136,330,360
Beginning balance at Mar. 31, 2022	64,190	$ 14	805,265	(741,001)	(88)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon vesting of restricted stock units (in shares)		2,882,673
Issuance of common stock in at the market offering (in shares)		14,584,801
Issuance of common stock in at the market offering	12,557	$ 1	12,556
Stock-based compensation	3,254		3,254
Unrealized (losses) gains on available-for-sale securities	(21)				(21)
Net loss	(26,938)			(26,938)
Ending balance (in shares) at Jun. 30, 2022		153,797,834
Ending balance at Jun. 30, 2022	$ 53,042	$ 15	$ 821,075	$ (767,939)	$ (109)

CONDENSED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
CONDENSED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	Jun. 30, 2022	Jun. 30, 2021
Operating activities
Net loss	$ (55,009)	$ (78,344)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation expense	407	787
Amortization of deferred financing costs	226	316
Amortization of deferred compensation for services	105	145
Amortization of premium on investment securities	16	274
Non-cash lease expense	1,698	1,318
Stock-based compensation	6,976	6,306
Change in derivative liabilities	18	(713)
Debt refinancing costs	102	0
Gain on sale of equipment	(853)	0
Non-cash interest associated with debt discount accretion	151	141
Changes in operating assets and liabilities:
Accounts receivable	(5,121)	0
Inventory	(4,529)	0
Prepaid commercial manufacturing	(12,197)	(8,481)
Prepaid expenses and other assets	1,848	1,102
Accounts payable	17	(3,039)
Accrued compensation and benefits	983	267
Operating lease liabilities	(1,692)	(1,361)
Accrued and other liabilities	259	2,607
Deferred revenue	7,694	182
Net cash used in operating activities	(58,901)	(78,493)
Investing activities
Proceeds from maturities and redemptions of investments	42,300	60,550
Purchases of investments	(25,762)	(48,314)
Proceeds from sale of property and equipment	1,268	0
Purchases of property and equipment	0	(1,517)
Net cash provided by investing activities	17,806	10,719
Financing activities
Proceeds from 2022 Loan, net of issuance costs	26,971	0
Repayment of 2018 Loan, net of settlement costs	(33,038)	0
Proceeds from the sale of future royalties, net of issuance costs	9,581	0
Proceeds from issuance of common stock in at the market offering, net of issuance costs	18,478	62,446
Proceeds from issuance of common stock under equity incentive and stock purchase plans	83	1,041
Net cash provided by financing activities	22,075	63,487
Net decrease in cash and cash equivalents	(19,020)	(4,287)
Cash and cash equivalents at beginning of period	72,428	91,032
Cash and cash equivalents at end of period	53,408	86,745
Supplementary disclosure of cash flow information:
Cash paid for interest	1,360	1,936
Cash paid for income taxes	6	3
Supplementary disclosure of non-cash activities:
Right-of-use assets obtained in exchange for lease obligations	0	14,379
Issuance of derivative in connection with issuance of loan payable	$ 375	$ 0

Organization and Basis of Presentation	6 Months Ended
Organization and Basis of Presentation	Jun. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Basis of Presentation	ORGANIZATION AND BASIS OF PRESENTATION Ardelyx, Inc. (the “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 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, 2021. The results for the three and six months ended June 30, 2022 are not necessarily indicative of results to be expected for the entire year ending December 31, 2022, 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, the 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 June 30, 2022, we had cash and investments of approximately $81.0 million. We have incurred operating losses since inception and our accumulated deficit as of June 30, 2022 is $767.9 million. Our current level of cash and investments alone is not sufficient to meet our plans for the next twelve months following the issuance of these financial statements. 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 financial statements. We plan to address our operating cash flow requirements with our current cash and investments, cash generated from sales of IBSRELA, our potential receipt of anticipated milestones from our collaboration partners, our potential receipt of anticipated payments from our Japanese collaboration partner under the second amendment to our License Agreement, our ability to access the capital markets, as well as 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 and 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 1 to our audited financial statements for the fiscal year ended December 31, 2021, included in our Annual Report on Form 10-K. Our significant accounting policies for the three and six months ended June 30, 2022 also included the policies discussed below related to accounts receivable, inventory, revenue and cost of revenue for commercial product sales. With the exception of those noted below, 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, 2021. Accounts Receivable Accounts receivable is reported net of allowances for returns, chargebacks and contractual discounts offered to our customers. Our estimate of the allowance for doubtful accounts is based on an evaluation of the aging of our receivables. Trade receivable balances are written off against the allowance when it is probable that the receivable will not be collected. To date, we have determined that an allowance for doubtful accounts is not required. As of June 30, 2022 our accounts receivable balance is comprised of $4.1 million from our collaborators and $1.5 million from commercial customers. As of December 31, 2021 our accounts receivable balance was comprised of $0.5 million from our collaborators. Inventory Prior to the regulatory approval of drug product candidates, we incurred expenses for the manufacture of drug product that could potentially be available to support the commercial launch of our products. We began to capitalize inventory costs associated with IBSRELA during the fourth quarter of 2021, when our intent to commercialize IBSRELA was established and we commenced preparation for the commercial launch of IBSRELA, which was when it was determined that the inventory had a probable future economic benefit. Inventory is stated at the lower of cost or estimated net realizable value with cost determined under the first-in first-out method. Inventory costs include third-party contract manufacturing, third-party packaging services, freight, labor costs for personnel involved in the manufacturing process, and indirect overhead costs. We primarily use actual costs to determine the cost basis for inventory. The determination of whether inventory costs will be realizable requires management review of the expiration dates of IBSRELA compared to our forecasted sales. If actual market conditions are less favorable than projected by management, write-downs of inventory may be required, which would be recorded as cost of goods sold in the condensed statement of operations and comprehensive loss. Product Sales, Net We account for our commercial product sales, net in accordance with Topic 606 - Revenue from Contracts with Customers. We received approval from the U.S. Food and Drug Administration (“FDA”) in September 2019 to market IBSRELA, the first and only sodium hydrogen exchanger 3 (“NHE3”) inhibitor for the treatment of irritable bowel syndrome with constipation ("IBS-C") in adults, in the United States ("U.S."). We began selling IBSRELA in the U.S. in March 2022. We distribute IBSRELA principally through a limited number of wholesalers and specialty pharmacy providers (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 and privately-negotiated 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. Reserves for Variable Consideration Revenues from product sales are recorded at the net sales price (transaction price), which includes estimates of variable consideration, including rebates, discounts, patient copay assistance programs, and estimated product returns. These estimates are based on the amounts earned or to be claimed for related sales and are classified as reductions of gross accounts receivable if the amount is payable to our Customers or a current liability if the amount is payable to a party other than a Customer. Where appropriate, these estimates are based on factors such as industry data and forecasted customer buying and payment patterns, our historical experience, current contractual and statutory requirements, specific known market events and trends. Overall, these reductions to gross sales reflect our best estimates of the amount of consideration to which we are entitled based on the terms of the contract. Variable consideration is included in the transaction price only to the extent that it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is subsequently resolved. Actual amounts of consideration ultimately received may differ from our estimates. If actual results in the future vary from our estimates, we adjust these estimates, which would affect product revenue and earnings in the period such variances become known. As we gain more historical experience, estimates will be more heavily based on the expected utilization from historical data we have accumulated since the IBSRELA product launch. Rebates: Rebates include mandated discounts under the Medicaid Drug Rebate Program ("Medicaid") and the Medicare Coverage Gap Program ("Medicare"). Rebates are amounts owed after the final dispensing of products to a benefit plan participant and are based upon contractual agreements or legal requirements with the public-sector benefit providers. These estimates for rebates are recorded in the same period the related gross revenue is recognized, resulting in a reduction of product revenue and the establishment of a current liability which is included in accrued expenses on the condensed balance sheets. We estimate our Medicaid and Medicare rebates based upon the estimated payor mix, and statutory discount rates. Our estimates for payor mix are guided by payor information received from specialty pharmacies, expected utilization for wholesaler sales to pharmacies, and available industry payor information. Chargebacks: Chargebacks are discounts that occur when certain contracted purchasers purchase directly from our wholesalers at a discounted price. The wholesaler, in turn, charges back the difference between the price initially paid to us by the wholesaler and the discounted price paid to the wholesaler by the contracted purchaser. Amounts for estimated chargebacks are established in the same period that the related gross revenue is recognized, resulting in a reduction of product revenue and accounts receivable. The accrual for wholesaler chargebacks is estimated based on known chargeback rates, known sales to wholesalers, and estimated utilization by types of contracted purchasers. Discounts and Fees: Our payment terms are generally 30 to 60 days. Wholesalers and specialty pharmacies are offered various forms of consideration, including service fees. Wholesalers may also receive prompt pay discounts for payment within a specified period. We expect prompt pay discounts to be earned when offered and therefore, we deduct the full amount of these discounts and service fees from product sales when revenue is recognized, resulting in a reduction of product revenue and accounts receivable. Other Reserves: Patients who have commercial insurance may receive co-pay assistance when product is dispensed by pharmacies to patients. We estimate the amount of co-pay assistance provided to eligible patients based on the terms of the program and redemption information provided by third-party claims processing organizations and are recorded in accounts payable and accrued expenses and other current liabilities on the condensed balance sheets. Cost of Revenue Cost of revenue consists of the cost of commercial goods sold to our Customers, international partners under product supply agreements, and royalty expense based on sales of tenapanor. We capitalize inventory costs associated with the production of our products after regulatory approval or when, based on management’s judgment, future commercialization is considered probable and the future economic benefit is expected to be realized. Otherwise, such costs are expensed as research and development. A portion of the costs of IBSRELA units recognized as revenue during the three and six months ended June 30, 2022 were expensed prior to 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. Cost of revenue includes payments due to AstraZeneca, which under the terms of a termination agreement entered into in 2015 (the "AZ Termination Agreement") is entitled to (i) future royalties at a 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 our collaboration partners as a result of the development and commercialization of tenapanor or certain other NHE3 inhibitors. We have agreed to pay AstraZeneca up to a maximum of $75.0 million in the aggregate for (i) and (ii). We recognize these expenses as cost of revenue when we recognize the corresponding revenue that gives rise to payments due to AstraZeneca. To date, we have recognized an aggregate of $11.9 million as cost of revenue under the AZ Termination Agreement. Non-cash Interest Expense on Deferred Royalty Obligation The net proceeds we receive from the sale of certain future royalties are amortized to non-cash interest expense over the estimated life of the associated agreement using the effective interest method. As we earn royalties and remit those royalties pursuant to the agreement, the balance of the deferred royalty obligation will be effectively repaid over the life of agreement. To determine the amortization of our deferred royalty obligation, we are required to estimate the total amount of future royalty payments we expect to earn. There are a number of factors that could materially affect the amount and timing of royalty payments, most of which are not within our control. We periodically assess the amount of royalty payments we expect to receive which are subject to the agreement 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. Recent Accounting Pronouncements New Accounting Pronouncements - Recently Adopted We have adopted no new accounting pronouncements other than those disclosed in 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 a have a material impact on our financial position, operations or cash flows.

Cash, Cash Equivalents and Investments

6 Months Ended

Jun. 30, 2022

Cash and Cash Equivalents [Abstract]

Cash, Cash Equivalents and Investments

CASH, CASH EQUIVALENTS AND INVESTMENTS

Securities classified as cash, cash equivalents and investments as of June 30, 2022 and December 31, 2021 are summarized below (in thousands):


	June 30, 2022
			Gross Unrealized
	Amortized Cost		Gains		Losses		Fair Value
Cash and cash equivalents:
Cash	$	2,975	$	—	$	—	$	2,975
Money market funds	50,433		—		—		50,433


Total cash and cash equivalents	53,408		—		—		53,408
Short-term investments:
Commercial paper	$	16,931	$	—	$	(49)	$	16,882
U.S. government-sponsored agency bonds	8,768		—		(45)		8,723
Corporate bonds	1,011		—		(12)		999
Asset-backed securities	1,003		—		(3)		1,000
Total short-term investments	27,713		—		(109)		27,604
Total cash equivalents and investments	$	81,121	$	—	$	(109)	$	81,012


	December 31, 2021
			Gross Unrealized
	Amortized Cost		Gains		Losses		Fair Value
Cash and cash equivalents:
Cash	$	1,253	$	—	$	—	$	1,253
Money market funds	71,175		—		—		71,175


Total cash and cash equivalents	72,428		—		—		72,428
Short-term investments
Commercial paper	$	31,936	$	1	$	(2)	$	31,935
Corporate bonds	7,025		—		(3)		7,022

Asset backed securities	5,306		—		(2)		5,304
Total short-term investments	44,267		1		(7)		44,261


Total cash equivalents and investments	$	116,695	$	1	$	(7)	$	116,689

Cash equivalents consist of money market funds and other debt securities 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 income (loss) within stockholders’ equity on our 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 (expense), net, in the statement of operations and comprehensive loss.

All short-term available-for-sale securities held as of June 30, 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, we write it down through the statement of operations and comprehensive loss to its fair value and establishes that value as a new cost basis for the investment. We did not identify any of our available-for-sale securities as other-than-temporarily impaired in any of the periods presented. As of June 30, 2022, no investment was in a continuous unrealized loss position for more than one year and we believe that it is more likely than not that the investments will be held until maturity or a forecasted recovery of fair value.

Fair Value Measurements

6 Months Ended

Jun. 30, 2022

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):


	June 30, 2022
	Total Fair Value		Level 1		Level 2		Level 3
Assets:
Money market funds	$	50,433	$	50,433	$	—	$	—
Commercial paper	16,882		—		16,882		—
U.S. government-sponsored agency bonds	8,723		—		8,723		—
Corporate bonds	999		—		999		—
Asset-backed securities	1,000		—		1,000		—

Total	$	78,037	$	50,433	$	27,604	$	—

Liabilities:
Derivative liabilities for exit fees	$	1,091	$	—	$	—	$	1,091
Total	$	1,091	$	—	$	—	$	1,091


	December 31, 2021
	Total Fair Value		Level 1		Level 2		Level 3
Assets:
Money market funds	$	71,175	$	71,175	$	—	$	—
Commercial paper	31,935		—		31,935		—
Corporate bonds	7,022		—		7,022		—

Asset-backed securities	5,304		—		5,304		—

Total	$	115,436	$	71,175	$	44,261	$	—

Liabilities:
Derivative liability for exit fee	$	698	$	—	$	—	$	698
Total	$	698	$	—	$	—	$	698

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 2022 Exit Fee, as defined and discussed in Note 9. Derivative Liability, are classified as Level 3.

The carrying amounts reflected in the 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 June 30, 2022 and December 31, 2021, due to their short-term nature.

Fair Value of Debt

The interest rates of our deferred royalty obligation and term loan facility approximate the rate at which we could obtain alternative financing. Therefore, the carrying amount of the deferred royalty obligation and the term loan facility approximated their fair values at June 30, 2022 and December 31, 2021. See Note 7. Deferred Royalty Obligation and Note 8. Borrowing for a description of the Level 3 inputs used to estimate the fair value of each respective liability.

- 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

Inventory

6 Months Ended

Jun. 30, 2022

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 consisted of the following (in thousands):


	June 30, 2022
Raw materials	$	460
Work in process	3,606
Finished goods	463
Total	$	4,529

Prepaid commercial manufacturing of $17.8 million and $9.4 million as of June 30, 2022 and December 31, 2021, respectively, consist 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. Prepayments for commercial manufacturing of $3.8 million as of June 30, 2022 that are expected to be converted into inventory after 12 months are included in other assets on our Condensed Balance Sheets.

Product Revenue, Net

6 Months Ended

Jun. 30, 2022

Revenue from Contract with Customer [Abstract]

Product Revenue, Net

PRODUCT REVENUE, NET

We received approval from the FDA in September 2019 to market IBSRELA, the first and only NHE3 inhibitor for the treatment of IBS-C in adults, in the U.S. We began selling IBSRELA in the U.S. in March 2022. We recorded net revenue for IBSRELA of $1.6 million and $2.0 million during the three and six months ended June 30, 2022, respectively.

Sales to AmerisourceBergen Drug Corporation, Cardinal Health, and McKesson Corporation made up 40.2%, 22.7%, and 24.6% of our gross product revenue during the three months ended June 30, 2022 and 35.1%, 21.7%, and 22.5% during the six months ended June 30, 2022.

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		Other Fees, Copay and Returns		Total
Balance as of December 31, 2021	$	—	$	—	$	—	$	—
Activity related to 2022 sales	84		329		322		735
Credits/deductions issued	(41)		(15)		(133)		(189)
Balance as of June 30, 2022	$	43	$	314	$	189	$	546

There were no product sales or gross-to-net accruals during the three and six months ended June 30, 2021.

- 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
-Topic 606
-URI https://asc.fasb.org/topic&trid=49130388

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 10
-URI https://asc.fasb.org/extlink&oid=126920106&loc=SL49130551-203045

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (b)(2)
-URI https://asc.fasb.org/extlink&oid=126920106&loc=SL49130556-203045

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126920106&loc=SL49130554-203045

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI https://asc.fasb.org/extlink&oid=126920106&loc=SL49130550-203045

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-Subparagraph (e)
-URI https://asc.fasb.org/extlink&oid=126920106&loc=SL49130554-203045

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126920106&loc=SL49130554-203045

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (d)
-URI https://asc.fasb.org/extlink&oid=126920106&loc=SL49130554-203045

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 15
-URI https://asc.fasb.org/extlink&oid=126920106&loc=SL49130558-203045

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=126920106&loc=SL49130554-203045

+ Details

Collaboration and Licensing Agreements

6 Months Ended

Jun. 30, 2022

Collaboration and Licensing Agreements

Collaboration and Licensing Agreements

COLLABORATION AND LICENSING AGREEMENTS

Kyowa Kirin Co., Ltd. (“KKC”)

2019 KKC Agreement

In November 2019, we entered into a research collaboration and option agreement with KKC (the “2019 KKC Agreement”) for research associated with identifying two preclinical compounds that are ready for designation as development compounds (“DCs”), with one compound inhibiting the first undisclosed target (“Program 1”), and a second inhibiting the second undisclosed target (“Program 2”). Pursuant to the 2019 KKC Agreement, upon completion of the research and designation by the research steering committee of one or more DCs, KKC has the right to execute one or more separate collaborative agreements relating to the development and commercialization of one or both DCs in certain specified territories.

Under the terms of the 2019 KKC Agreement, KKC paid us a non-refundable, non-creditable upfront fee of $10.0 million in two installments as follows: the first installment of $5.0 million within 30 days of November 11, 2019 (the “Effective Date”), and the second installment of $5.0 million on the first anniversary of the Effective Date. The original term of the 2019 KKC Agreement commenced on the Effective Date and was to end on the earliest of: (i) 2 years following the Effective Date, (ii) the nomination of a program DC for both programs, (iii) the nomination of one program DC and the decision by the parties to cease research for the other program, or (iv) the decision by the parties to cease research for both programs. We entered into three amendments to the 2019 KKC Agreement, which have resulted in the extension of the original term. Under the third amendment to the 2019 KKC Agreement entered into on June 28, 2022, the current term will end on February 28, 2023.

We have no material future obligations under the 2019 KKC Agreement and recorded no revenue under the 2019 KKC Agreement during the three and six months ended June 30, 2022. During the three and six months ended June 30, 2021, we recognized $1.3 million and $2.8 million, respectively, as collaborative development revenue under the 2019 KKC Agreement in the accompanying condensed statement of operations and comprehensive loss.

2017 KKC Agreement

In November 2017, we entered into an exclusive license agreement with KKC (the “2017 KKC Agreement”), for the development, commercialization, and distribution of tenapanor in Japan for cardiorenal indications. We granted KKC 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 KKC Agreement, KKC 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 KKC’s use in development and commercialization throughout the term of the 2017 KKC Agreement, provided that KKC may exercise an option to manufacture the tenapanor drug substance under certain conditions.

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, KKC, is a customer. Under the terms of the 2017 KKC 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 KKC Agreement, and as such, each of the performance obligations is distinct.

Under the terms of the 2017 KKC Agreement, KKC 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 $10.0 million has been received and recognized as revenue as of June 30, 2022. We may also be eligible to receive approximately ¥8.5 billion for commercialization milestones, or approximately $62.3 million at the currency exchange rate on June 30, 2022, 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, the future royalties and commercial milestone payments we may receive under the 2017 KKC 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 has not been included in the transaction price as these were fully constrained at June 30, 2022.

On April 11, 2022, we entered into a second amendment (the "Amendment") to the 2017 KKC Agreement. Under the terms of the Amendment, we and KKC have agreed to a reduction in the royalty rate payable to us by KKC upon net sales of tenapanor 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, the future commercial milestones and royalties we may receive under the 2017 KKC 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, KKC has agreed to pay us up to an additional $40.0 million payable in two tranches, with the first payment due following KKC'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 KKC’s receipt of regulatory approval to market tenapanor for hyperphosphatemia in Japan. The variable consideration related to the reduction in the royalty rate has not been included in the transaction price as these were fully constrained at June 30, 2022.

During the three and six months ended June 30, 2022 we recognized no licensing revenue upon the achievement of development milestones. During the three and six months ended June 30, 2021, we recognized zero and $5.0 million respectively, as licensing revenue upon the initiation of phase 3 clinical studies by KKC in Japan to evaluate tenapanor for hyperphosphatemia. During the three and six months ended June 30, 2022, we recognized $952 thousand and $966 thousand, respectively, as product supply revenue related to the manufacturing supply of tenapanor and other materials to KKC pursuant to the 2017 KKC Agreement. During the three and six months ended June 30, 2021, we recognized zero and $126 thousand, respectively, as product supply revenue pursuant to the 2017 KKC Agreement.

As detailed below under the heading Deferred revenue - non-current, we have received prepayments from KKC for the manufacturing of tenapanor drug substance that will be used to satisfy KKC needs.

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

In December 2017, we entered into an exclusive license agreement with Fosun Pharma (the “Fosun Agreement”), for the development, commercialization and distribution of tenapanor in China for both hyperphosphatemia and IBS-C. Under the terms of the Fosun Agreement, Fosun paid us a $12.0 million upfront license fee. We may be entitled to receive development and commercialization milestones of up to $113.0 million, of which $3.0 million has been received and recognized as revenue as of June 30, 2022, 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 has not been included in the transaction price as these were fully constrained at June 30, 2022.

We have recorded no revenue during the three and six months ended June 30, 2022 or 2021 related to the Fosun Agreement.

Knight Therapeutics, Inc. (“Knight“)

In March 2018, we entered into an exclusive license agreement with Knight (the “Knight Agreement”) for the development, commercialization and distribution of tenapanor in Canada for hyperphosphatemia and IBS-C. Under the terms of the Knight Agreement, Knight paid us a $2.3 million upfront payment. We may also be eligible to receive approximately CAD22.2 million for development and commercialization milestones, or approximately $17.2 million at the currency exchange rate on June 30, 2022, of which $0.7 million has been received and recognized as revenue as of June 30, 2022. We are also eligible to receive royalties throughout the term of the agreement, and a transfer price for manufacturing services. The variable consideration related to the remaining development milestone payments has not been included in the transaction price as they were fully constrained at June 30, 2022.

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 licensee of tenapanor or another NHE3 inhibitor, up to a maximum of $75.0 million in aggregate for (i) and (ii). As of June 30, 2022, to date in aggregate, we have recognized $11.9 million of the $75.0 million, which has been recorded as cost of revenue, and have paid AstraZeneca $11.6 million. During the three and six months ended June 30, 2022 we recognized and recorded as cost of revenue $0.2 million and $0.3 million, respectively, related to the AstraZeneca Termination Agreement. During the three and six months ended June 30, 2021 we recognized zero and $1.0 million, respectively, 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. The June 30, 2022 and 2021 current deferred revenue balance is attributable entirely to the 2019 KKC Agreement and the non-current deferred revenue balances are attributable entirely to the 2017 KKC Agreement (in thousands):


Deferred revenue - current	2022		2021
Balance at January 1,	$	—	$	4,177


Decreases due to revenue recognized in the period for which cash has been received	—		(2,765)

Balance at June 30,	$	—	$	1,412


Deferred revenue - non-current	2022		2021
Balance at January 1,	$	4,727	$	—
Increases due to cash received during the period	3,829		2,947
Increases to amounts invoiced, for which cash has not yet been received	3,865		—


Balance at June 30,	$	12,421	$	2,947

Deferred Royalty Obligation	6 Months Ended
Deferred Royalty Obligation	Jun. 30, 2022
Advance Royalties [Abstract]
Deferred Royalty Obligation	DEFERRED ROYALTY OBLIGATION On June 28, 2022, we and HealthCare Royalty Partners IV, L.P. (“HCR”) entered into a Royalty and Sales Milestone Interest Acquisition Agreement (the “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 KKC based upon KKC's net sales of tenapanor in Japan. 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 KKC's receipt of regulatory approval to market tenapanor for hyperphosphatemia in Japan, and another $5.0 million payment in the event net sales by KKC 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 KKC Agreement, to create or incur any liens with respect to the Royalty Interest Payments, the 2017 KKC Agreement or certain patents, or to sell, license or transfer certain patents in the field and territory described in the 2017 KKC 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 KKC 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 KKC 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 on our condensed balance sheet. As part of the sale, we incurred approximately $0.4 million in transaction costs, which, along with the deferred royalty obligation, will be 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 KKC, and subsequently from us to HCR, the balance of the deferred royalty obligation will be effectively repaid over the life of the HCR Agreement. To determine the amortization of the deferred royalty obligation, we are required to estimate the total amount of future royalty payments to be received from KKC for sales of tenapanor in Japan. There are a number of factors that could materially affect the amount and timing of royalty payments from KKC, most of which are not within our control. We will periodically assess the estimated royalty payments from KKC and, to the extent that the amount or timing of such payments is materially different than our original estimates, we will prospectively adjust the imputed interest rate and the related amortization of the deferred royalty obligation. As of June 30, 2022, our effective interest rate used to amortize the liability is 34.4%. During the three and six months ended June 30, 2022, we did not recognize a material amount of non-cash interest expense for the amortization of the deferred royalty obligation.

Borrowing

6 Months Ended

Jun. 30, 2022

Debt Disclosure [Abstract]

Borrowing

BORROWING

Solar Capital and Western Alliance Bank Loan Agreement

On May 16, 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 $50.0 million loan facility 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 (the “Closing Date”), we entered into a loan and security agreement (the “2022 Loan Agreement”) with SLR Investment Corp. as collateral agent (the “Agent”), and the lenders listed in the 2022 Loan Agreement (collectively the “2022 Lenders”). The 2022 Loan Agreement provides for a senior secured loan facility, with $27.5 million (the “Term A Loan”) funded on the Closing Date and an additional $22.5 million that we may borrow on or prior to July 25, 2023; provided that (i) we have received approval by the FDA for our NDA for the control of serum phosphorus in chronic kidney disease patients on dialysis by December 31, 2022, and (ii) we have achieved certain product revenue milestone targets described in the 2022 Loan Agreement (the “Term B Loan”, and collectively, the Term A Loan and the Term B Loan, the “2022 Loan”). On August 1, 2022, we entered into an amendment to the 2022 Loan Agreement with SLR Investment Corp. that extends the date by which we must receive approval by the FDA for our NDA for the control of serum phosphorus in chronic kidney disease patients on dialysis in order to borrow the additional $22.5 million from December 31, 2022 to March 31, 2023. 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 bear interest at a floating per annum rate equal to 7.95% plus the greater of (i) one tenth percent (0.10%) and (ii) the one-month rate published by the Intercontinental Exchange Benchmark Administration Ltd or its successor. We are permitted to make interest-only payments on the 2022 Loan through March 31, 2024. Accordingly, beginning on April 1, 2024, we will be required to make monthly payments of interest plus repay the 2022 Loan in consecutive equal monthly installments of principal over 36 months. 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 (the “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 June 30, 2022 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 financial statements.

As of June 30, 2022, our future payment obligations related to the 2022 Loan, excluding interest payments and the 2022 final fee, are as follows (in thousands):


Total repayment obligations	$	28,862
Less: Unamortized discount	(1,259)
Less: Unaccreted value of final fee	(1,230)
Long-term debt	26,373
Less: Current portion of long-term debt	(26,373)
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

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+ Details

Derivative Liability

6 Months Ended

Jun. 30, 2022

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Derivative Liability

DERIVATIVE LIABILITY

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 (the “2018 Exit Fee”) upon any change of control transaction in respect of the Company or if we obtain both (i) FDA approval of tenapanor for the control of serum phosphorus in adult patients with CKD on dialysis and (ii) FDA approval of tenapanor for the treatment of patients with IBS-C, which was obtained on September 12, 2019 when the FDA approved IBSRELA® (tenapanor), a 50 milligram, twice daily oral pill for the treatment of IBS-C in adults (the “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 expenses and other current liabilities on the accompanying condensed balance sheets. As of both June 30, 2022 and December 31, 2021, the estimated fair value of the 2018 Exit Fee was $0.7 million.

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 2018 derivative liability include: (i) our estimates of both the probability and timing of a potential $1.5 million payment to the 2018 Lenders 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 (or a comparable successor rate if LIBOR no longer exists). 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 10.0% 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

On February 23, 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 (the “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 (the "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 June 30, 2022, the estimated fair value of the 2022 Exit Fee is $0.4 million.

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 chronic kidney disease patients on dialysis by December 31, 2022, 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 10.0% increase (decrease) in the probability of occurrence would not result in a material fair value fluctuation.

Changes in the fair value of our exit fee derivative liabilities recurring measurements included in Level 3 of the fair value hierarchy are presented as other income, net in our statements of operations and were as follows for the three and six months ended June 30, 2022 and 2021 (in thousands):


	2022		2021
Balance at January 1,	$	698	$	1,376
2022 Exit Fee addition at fair value	375		—
Changes in estimated fair value:
2018 Exit Fee	$	(29)	$	(713)
2022 Exit Fee	$	47	$	—
Balance at June 30,	$	1,091	$	663

Leases

6 Months Ended

Jun. 30, 2022

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	June 30, 2022			December 31, 2021
Right-of-use assets	$	11,054		$	12,752

Current portion of lease liabilities	3,691			3,492
Operating lease liability, net of current portion	7,857			9,748
Total	$	11,548		$	13,240

Weighted-average remaining life (years)	2.9			3.4
Weighted-average discount rate	6.8		%	6.9		%

Lease costs, which are included in operating expenses in our statements of operations, were as follows (in thousands):


	Three Months Ended June 30,				Six Months Ended June 30,
	2022		2021		2022		2021
Operating lease expense	$	1,064	$	837	$	2,128	$	1,510
Cash paid for operating lease	$	1,064	$	766	$	2,122	$	1,554

The following table summarizes our undiscounted cash payment obligations for our operating lease liabilities as of June 30, 2022 (in thousands):


Remainder of 2022	$	2,170
2023	4,440
2024	4,589
2025	1,321
2026	252

Total undiscounted operating lease payments	12,772
Imputed interest expenses	(1,224)
Total operating lease liabilities	11,548
Less: Current portion of operating lease liability	(3,691)
Operating lease liability, net of current portion	$	7,857

Stockholders' Equity	6 Months Ended
Stockholders' Equity	Jun. 30, 2022
Stockholders' Equity Note [Abstract]
Stockholders' Equity	STOCKHOLDERS’ EQUITY At the Market Offerings Agreement In July 2020, we filed a Form S-3 registration statement, which became effective in August 2020 ("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 $100.0 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” (the "2020 Open Market Sales Agreement"). The 2020 Open Market Sales Agreement was fully utilized as of December 31, 2021. During the six months ended June 30, 2021 we sold 9.0 million shares and received gross proceeds of $63.8 million at a weighted average sales price of approximately $7.10 per share under the 2020 Open Market Sales Agreement. In August 2021, we filed an additional prospectus supplement under the Registration Statement 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 an additional 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. We are not required to sell shares under the 2021 Open Market Sales Agreement. Pursuant to the 2021 Open Market Sales Agreement, Jefferies, as our sales agent, receives 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 six months ended June 30, 2022 we sold 20.5 million shares and received gross proceeds of $18.9 million at a weighted average sales price of approximately $0.92 per share under the 2021 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
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-Name Accounting Standards Codification
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+ Details

Equity Incentive Plans

6 Months Ended

Jun. 30, 2022

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"), performance-based restricted stock units ("PRSUs") 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 June 30,				Six Months Ended June 30,
	2022		2021		2022		2021
Selling, general and administrative	$	2,220	$	2,132	$	4,728	$	4,127
Research and development	973		1,087		2,096		2,179

Total	$	3,193	$	3,219	$	6,824	$	6,306

As of June 30, 2022, the balance of inventory included in our condensed balance sheet includes $0.2 million stock-based compensation. During the three and six months ending June 30, 2022, the amount of stock-based compensation released from inventory into cost of revenue was not material.

As of June 30, 2022, 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	$	13,096	2.7
RSU grants	$	3,524	2.9
ESPP	$	21	0.2

Stock Options

A summary of our stock option activity and related information for the six months ended June 30, 2022 is as follows (in thousands, except dollar amounts):


	Number of Shares	Weighted-Average Exercise Price per Share
Balance at December 31, 2021	10,417	$	7.00
Options granted	4,773	$	0.88
Options exercised	—	$	—
Options forfeited or canceled	(1,190)	$	7.04
Balance at June 30, 2022	14,000	$	4.91
Exercisable at June 30, 2022	7,085	$	6.91

Restricted Stock Units

A summary of our RSUs activity and related information for the six months ended June 30, 2022 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, 2021	3,529	$	2.04
Granted	1,980	$	0.81
Vested	(3,714)	$	1.26
Forfeited	(121)	$	2.85
Non-vested restricted stock units at June 30, 2022	1,674	$	2.26

Employee Stock Purchase Plan

In February 2022, we sold approximately 0.1 million shares of our common stock under the ESPP. The shares were purchased by employees at a purchase price of $0.65 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 six months ended June 30, 2022, we issued no shares of our common stock to members of the board of directors in accordance with the program.

Net Loss Per Share

6 Months Ended

Jun. 30, 2022

Earnings Per Share [Abstract]

Net Loss Per Share

NET LOSS PER SHAREBasic 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 six months ended June 30, 2022 and 2021, 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 June 30,				Six Months Ended June 30,
Numerator:	2022		2021		2022		2021
Net loss	$	(26,938)	$	(45,189)	$	(55,009)	$	(78,344)
Denominator:
Weighted average common shares outstanding - basic and diluted	145,544		100,040		138,280		98,618
Net loss per share - basic and diluted	$	(0.19)	$	(0.45)	$	(0.40)	$	(0.79)

For the periods presented, all common stock equivalents are excluded from the computation of diluted loss per share, as the result would be anti-dilutive, including the following (in thousands):


	Three Months Ended June 30,				Six Months Ended June 30,
	2022		2021		2022		2021
Options to purchase common stock	$	13,099	$	12,447	$	13,182	$	12,211

Restricted stock units	3,520		1,125		3,963		1,006

ESPP shares issuable	200		230		176		188
Total	$	16,819	$	13,802	$	17,321	$	13,406

Contingencies	6 Months Ended
Contingencies	Jun. 30, 2022
Commitments and Contingencies Disclosure [Abstract]
Contingencies	CONTINGENCIESFrom time to time we may be involved in claims arising in connection with our business. Based on information currently available, management believes that the amount, or range, of reasonably possible losses in connection with any pending actions against us will not be material to our financial condition or cash flows, and no contingent liabilities were accrued as of June 30, 2022 or 2021.

Organization and Basis of Presentation (Policies)

6 Months Ended

Jun. 30, 2022

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, 2021. The results for the three and six months ended June 30, 2022 are not necessarily indicative of results to be expected for the entire year ending December 31, 2022, 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, the 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.

Accounts Receivable

Accounts ReceivableAccounts receivable is reported net of allowances for returns, chargebacks and contractual discounts offered to our customers. Our estimate of the allowance for doubtful accounts is based on an evaluation of the aging of our receivables. Trade receivable balances are written off against the allowance when it is probable that the receivable will not be collected. To date, we have determined that an allowance for doubtful accounts is not required.

Inventory

Prior to the regulatory approval of drug product candidates, we incurred expenses for the manufacture of drug product that could potentially be available to support the commercial launch of our products. We began to capitalize inventory costs associated with IBSRELA during the fourth quarter of 2021, when our intent to commercialize IBSRELA was established and we commenced preparation for the commercial launch of IBSRELA, which was when it was determined that the inventory had a probable future economic benefit.

Inventory is stated at the lower of cost or estimated net realizable value with cost determined under the first-in first-out method. Inventory costs include third-party contract manufacturing, third-party packaging services, freight, labor costs for personnel involved in the manufacturing process, and indirect overhead costs. We primarily use actual costs to determine the cost basis for inventory. The determination of whether inventory costs will be realizable requires management review of the expiration dates of IBSRELA compared to our forecasted sales. If actual market conditions are less favorable than projected by management, write-downs of inventory may be required, which would be recorded as cost of goods sold in the condensed statement of operations and comprehensive loss.

Product Sales, Net and Reserves for Variable Consideration

Product Sales, Net

We account for our commercial product sales, net in accordance with Topic 606 - Revenue from Contracts with Customers. We received approval from the U.S. Food and Drug Administration (“FDA”) in September 2019 to market IBSRELA, the first and only sodium hydrogen exchanger 3 (“NHE3”) inhibitor for the treatment of irritable bowel syndrome with constipation ("IBS-C") in adults, in the United States ("U.S."). We began selling IBSRELA in the U.S. in March 2022. We distribute IBSRELA principally through a limited number of wholesalers and specialty pharmacy providers (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 and privately-negotiated 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.

Reserves for Variable Consideration

Revenues from product sales are recorded at the net sales price (transaction price), which includes estimates of variable consideration, including rebates, discounts, patient copay assistance programs, and estimated product returns. These estimates are based on the amounts earned or to be claimed for related sales and are classified as reductions of gross accounts receivable if the amount is payable to our Customers or a current liability if the amount is payable to a party other than a Customer. Where appropriate, these estimates are based on factors such as industry data and forecasted customer buying and payment patterns, our historical experience, current contractual and statutory requirements, specific known market events and trends. Overall, these reductions to gross sales reflect our best estimates of the amount of consideration to which we are entitled based on the terms of the contract. Variable consideration is included in the transaction price only to the extent that it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is subsequently resolved. Actual amounts of consideration ultimately received may differ from our estimates. If actual results in the future vary from our estimates, we adjust these estimates, which would affect product revenue and earnings in the period such variances become known. As we gain more historical experience, estimates will be more heavily based on the expected utilization from historical data we have accumulated since the IBSRELA product launch.

Rebates: Rebates include mandated discounts under the Medicaid Drug Rebate Program ("Medicaid") and the Medicare Coverage Gap Program ("Medicare"). Rebates are amounts owed after the final dispensing of products to a benefit plan participant and are based upon contractual agreements or legal requirements with the public-sector benefit providers. These estimates for rebates are recorded in the same period the related gross revenue is recognized, resulting in a reduction of product revenue and the establishment of a current liability which is included in accrued expenses on the condensed balance sheets. We estimate our Medicaid and Medicare rebates based upon the estimated payor mix, and statutory discount rates. Our estimates for payor mix are guided by payor information received from specialty pharmacies, expected utilization for wholesaler sales to pharmacies, and available industry payor information.

Chargebacks: Chargebacks are discounts that occur when certain contracted purchasers purchase directly from our wholesalers at a discounted price. The wholesaler, in turn, charges back the difference between the price initially paid to us by the wholesaler and the discounted price paid to the wholesaler by the contracted purchaser. Amounts for estimated chargebacks are established in the same period that the related gross revenue is recognized, resulting in a reduction of product revenue and accounts receivable. The accrual for wholesaler chargebacks is estimated based on known chargeback rates, known sales to wholesalers, and estimated utilization by types of contracted purchasers.

Discounts and Fees: Our payment terms are generally 30 to 60 days. Wholesalers and specialty pharmacies are offered various forms of consideration, including service fees. Wholesalers may also receive prompt pay discounts for payment within a specified period. We expect prompt pay discounts to be earned when offered and therefore, we deduct the full amount of these discounts and service fees from product sales when revenue is recognized, resulting in a reduction of product revenue and accounts receivable.

Other Reserves: Patients who have commercial insurance may receive co-pay assistance when product is dispensed by pharmacies to patients. We estimate the amount of co-pay assistance provided to eligible patients based on the terms of the program and redemption information provided by third-party claims processing organizations and are recorded in accounts payable and accrued expenses and other current liabilities on the condensed balance sheets.

Cost of Revenue

Cost of revenue consists of the cost of commercial goods sold to our Customers, international partners under product supply agreements, and royalty expense based on sales of tenapanor. We capitalize inventory costs associated with the production of our products after regulatory approval or when, based on management’s judgment, future commercialization is considered probable and the future economic benefit is expected to be realized. Otherwise, such costs are expensed as research and development. A portion of the costs of IBSRELA units recognized as revenue during the three and six months ended June 30, 2022 were expensed prior to 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.

Cost of revenue includes payments due to AstraZeneca, which under the terms of a termination agreement entered into in 2015 (the "AZ Termination Agreement") is entitled to (i) future royalties at a 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 our collaboration partners as a result of the development and commercialization of tenapanor or certain other NHE3 inhibitors. We have agreed to pay AstraZeneca up to a maximum of $75.0 million in the aggregate for (i) and (ii). We recognize these expenses as cost of revenue when we recognize the corresponding revenue that gives rise to payments due to AstraZeneca. To date, we have recognized an aggregate of $11.9 million as cost of revenue under the AZ Termination Agreement.

Non-cash Interest Expense on Deferred Royalty Obligation

The net proceeds we receive from the sale of certain future royalties are amortized to non-cash interest expense over the estimated life of the associated agreement using the effective interest method. As we earn royalties and remit those royalties pursuant to the agreement, the balance of the deferred royalty obligation will be effectively repaid over the life of agreement. To determine the amortization of our deferred royalty obligation, we are required to estimate the total amount of future royalty payments we expect to earn. There are a number of factors that could materially affect the amount and timing of royalty payments, most of which are not within our control. We periodically assess the amount of royalty payments we expect to receive which are subject to the agreement 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.

Recent Accounting Pronouncements

New Accounting Pronouncements - Recently Adopted

We have adopted no new accounting pronouncements other than those disclosed in 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 a 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.

Cash, Cash Equivalents and Investments (Tables)

6 Months Ended

Jun. 30, 2022

Cash and Cash Equivalents [Abstract]

Schedule of Securities Classified as Cash, Cash Equivalents and Investments

Securities classified as cash, cash equivalents and investments as of June 30, 2022 and December 31, 2021 are summarized below (in thousands):


	June 30, 2022
			Gross Unrealized
	Amortized Cost		Gains		Losses		Fair Value
Cash and cash equivalents:
Cash	$	2,975	$	—	$	—	$	2,975
Money market funds	50,433		—		—		50,433


Total cash and cash equivalents	53,408		—		—		53,408
Short-term investments:
Commercial paper	$	16,931	$	—	$	(49)	$	16,882
U.S. government-sponsored agency bonds	8,768		—		(45)		8,723
Corporate bonds	1,011		—		(12)		999
Asset-backed securities	1,003		—		(3)		1,000
Total short-term investments	27,713		—		(109)		27,604
Total cash equivalents and investments	$	81,121	$	—	$	(109)	$	81,012


	December 31, 2021
			Gross Unrealized
	Amortized Cost		Gains		Losses		Fair Value
Cash and cash equivalents:
Cash	$	1,253	$	—	$	—	$	1,253
Money market funds	71,175		—		—		71,175


Total cash and cash equivalents	72,428		—		—		72,428
Short-term investments
Commercial paper	$	31,936	$	1	$	(2)	$	31,935
Corporate bonds	7,025		—		(3)		7,022

Asset backed securities	5,306		—		(2)		5,304
Total short-term investments	44,267		1		(7)		44,261


Total cash equivalents and investments	$	116,695	$	1	$	(7)	$	116,689

Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2022

Fair Value Disclosures [Abstract]

Summary of Fair Value of Financial Assets and Liabilities Measured or Disclosed 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):


	June 30, 2022
	Total Fair Value		Level 1		Level 2		Level 3
Assets:
Money market funds	$	50,433	$	50,433	$	—	$	—
Commercial paper	16,882		—		16,882		—
U.S. government-sponsored agency bonds	8,723		—		8,723		—
Corporate bonds	999		—		999		—
Asset-backed securities	1,000		—		1,000		—

Total	$	78,037	$	50,433	$	27,604	$	—

Liabilities:
Derivative liabilities for exit fees	$	1,091	$	—	$	—	$	1,091
Total	$	1,091	$	—	$	—	$	1,091


	December 31, 2021
	Total Fair Value		Level 1		Level 2		Level 3
Assets:
Money market funds	$	71,175	$	71,175	$	—	$	—
Commercial paper	31,935		—		31,935		—
Corporate bonds	7,022		—		7,022		—

Asset-backed securities	5,304		—		5,304		—

Total	$	115,436	$	71,175	$	44,261	$	—

Liabilities:
Derivative liability for exit fee	$	698	$	—	$	—	$	698
Total	$	698	$	—	$	—	$	698

Inventory (Tables)

6 Months Ended

Jun. 30, 2022

Inventory Disclosure [Abstract]

Schedule of Inventory

Inventory consisted of the following (in thousands):


	June 30, 2022
Raw materials	$	460
Work in process	3,606
Finished goods	463
Total	$	4,529

Product Revenue, Net (Tables)

6 Months Ended

Jun. 30, 2022

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		Other Fees, Copay and Returns		Total
Balance as of December 31, 2021	$	—	$	—	$	—	$	—
Activity related to 2022 sales	84		329		322		735
Credits/deductions issued	(41)		(15)		(133)		(189)
Balance as of June 30, 2022	$	43	$	314	$	189	$	546

Collaboration and Licensing Agreements (Tables)

6 Months Ended

Jun. 30, 2022

Collaboration and Licensing Agreements

Schedule of Changes in Deferred Revenue


Deferred revenue - current	2022		2021
Balance at January 1,	$	—	$	4,177


Decreases due to revenue recognized in the period for which cash has been received	—		(2,765)

Balance at June 30,	$	—	$	1,412


Deferred revenue - non-current	2022		2021
Balance at January 1,	$	4,727	$	—
Increases due to cash received during the period	3,829		2,947
Increases to amounts invoiced, for which cash has not yet been received	3,865		—


Balance at June 30,	$	12,421	$	2,947

Borrowing (Tables)

6 Months Ended

Jun. 30, 2022

Debt Disclosure [Abstract]

Schedule of Future Debt Payment Obligations

As of June 30, 2022, our future payment obligations related to the 2022 Loan, excluding interest payments and the 2022 final fee, are as follows (in thousands):


Total repayment obligations	$	28,862
Less: Unamortized discount	(1,259)
Less: Unaccreted value of final fee	(1,230)
Long-term debt	26,373
Less: Current portion of long-term debt	(26,373)
Long-term debt, net of current portion	$	—

Derivative Liability (Tables)

6 Months Ended

Jun. 30, 2022

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Schedule of Changes in Fair Value of Derivative Liability


	2022		2021
Balance at January 1,	$	698	$	1,376
2022 Exit Fee addition at fair value	375		—
Changes in estimated fair value:
2018 Exit Fee	$	(29)	$	(713)
2022 Exit Fee	$	47	$	—
Balance at June 30,	$	1,091	$	663

Leases (Tables)

6 Months Ended

Jun. 30, 2022

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	June 30, 2022			December 31, 2021
Right-of-use assets	$	11,054		$	12,752

Current portion of lease liabilities	3,691			3,492
Operating lease liability, net of current portion	7,857			9,748
Total	$	11,548		$	13,240

Weighted-average remaining life (years)	2.9			3.4
Weighted-average discount rate	6.8		%	6.9		%

Summary of Lease Costs

Lease costs, which are included in operating expenses in our statements of operations, were as follows (in thousands):


	Three Months Ended June 30,				Six Months Ended June 30,
	2022		2021		2022		2021
Operating lease expense	$	1,064	$	837	$	2,128	$	1,510
Cash paid for operating lease	$	1,064	$	766	$	2,122	$	1,554

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 June 30, 2022 (in thousands):


Remainder of 2022	$	2,170
2023	4,440
2024	4,589
2025	1,321
2026	252

Total undiscounted operating lease payments	12,772
Imputed interest expenses	(1,224)
Total operating lease liabilities	11,548
Less: Current portion of operating lease liability	(3,691)
Operating lease liability, net of current portion	$	7,857

Equity Incentive Plans (Tables)

6 Months Ended

Jun. 30, 2022

Share-Based Payment Arrangement [Abstract]

Summary of Stock-Based Compensation Expense Recognized


	Three Months Ended June 30,				Six Months Ended June 30,
	2022		2021		2022		2021
Selling, general and administrative	$	2,220	$	2,132	$	4,728	$	4,127
Research and development	973		1,087		2,096		2,179

Total	$	3,193	$	3,219	$	6,824	$	6,306

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

As of June 30, 2022, 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	$	13,096	2.7
RSU grants	$	3,524	2.9
ESPP	$	21	0.2

Schedule of Stock Option Activity

A summary of our stock option activity and related information for the six months ended June 30, 2022 is as follows (in thousands, except dollar amounts):


	Number of Shares	Weighted-Average Exercise Price per Share
Balance at December 31, 2021	10,417	$	7.00
Options granted	4,773	$	0.88
Options exercised	—	$	—
Options forfeited or canceled	(1,190)	$	7.04
Balance at June 30, 2022	14,000	$	4.91
Exercisable at June 30, 2022	7,085	$	6.91

Schedule of Restricted Stock Units Activity

A summary of our RSUs activity and related information for the six months ended June 30, 2022 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, 2021	3,529	$	2.04
Granted	1,980	$	0.81
Vested	(3,714)	$	1.26
Forfeited	(121)	$	2.85
Non-vested restricted stock units at June 30, 2022	1,674	$	2.26

Net Loss Per Share (Tables)

6 Months Ended

Jun. 30, 2022

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 June 30,				Six Months Ended June 30,
Numerator:	2022		2021		2022		2021
Net loss	$	(26,938)	$	(45,189)	$	(55,009)	$	(78,344)
Denominator:
Weighted average common shares outstanding - basic and diluted	145,544		100,040		138,280		98,618
Net loss per share - basic and diluted	$	(0.19)	$	(0.45)	$	(0.40)	$	(0.79)

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

For the periods presented, all common stock equivalents are excluded from the computation of diluted loss per share, as the result would be anti-dilutive, including the following (in thousands):


	Three Months Ended June 30,				Six Months Ended June 30,
	2022		2021		2022		2021
Options to purchase common stock	$	13,099	$	12,447	$	13,182	$	12,211

Restricted stock units	3,520		1,125		3,963		1,006

ESPP shares issuable	200		230		176		188
Total	$	16,819	$	13,802	$	17,321	$	13,406

Organization and Basis of Presentation (Details) $ in Thousands	1 Months Ended	6 Months Ended
	Jun. 30, 2015 USD ($)	Jun. 30, 2022 USD ($) segment	Dec. 31, 2021 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of segments \| segment		1
Cash and investments		$ 81,012	$ 116,689
Accumulated deficit		(767,939)	(712,930)
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Accounts receivable		5,623	502
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		$ 11,900
Minimum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Payment terms		30 days
Maximum
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Payment terms		60 days
Collaborators
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Accounts receivable		$ 4,100	$ 500
Commercial customers
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Accounts receivable		$ 1,500

Cash, Cash Equivalents and Investments - Securities Classified as Cash, Cash Equivalents and Investments (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Cash and cash equivalents:
Amortized Cost	$ 53,408	$ 72,428
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	53,408	72,428
Short-term investments:
Amortized Cost	27,713	44,267
Gross Unrealized Gains	0	1
Gross Unrealized Losses	(109)	(7)
Fair Value	27,604	44,261
Amortized Cost	81,121	116,695
Gross Unrealized Gains	0	1
Gross Unrealized Losses	(109)	(7)
Fair Value	81,012	116,689
Commercial paper
Short-term investments:
Amortized Cost	16,931	31,936
Gross Unrealized Gains	0	1
Gross Unrealized Losses	(49)	(2)
Fair Value	16,882	31,935
U.S. government-sponsored agency bonds
Short-term investments:
Amortized Cost	8,768
Gross Unrealized Gains	0
Gross Unrealized Losses	(45)
Fair Value	8,723
Corporate bonds
Short-term investments:
Amortized Cost	1,011	7,025
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(12)	(3)
Fair Value	999	7,022
Asset-backed securities
Short-term investments:
Amortized Cost	1,003	5,306
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(3)	(2)
Fair Value	1,000	5,304
Cash
Cash and cash equivalents:
Amortized Cost	2,975	1,253
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	2,975	1,253
Money market funds
Cash and cash equivalents:
Amortized Cost	50,433	71,175
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	$ 50,433	$ 71,175

Cash, Cash Equivalents and Investments - Narrative (Details)	6 Months Ended
	Jun. 30, 2022 investment
Cash and Cash Equivalents [Abstract]
Short-term available-for-sale securities contractual maturities, maximum	1 year
Number of investments in unrealized loss position	0

Fair Value Measurements (Details) - Recurring - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Assets:
Assets, fair value	$ 78,037	$ 115,436
Liabilities:
Liabilities, fair value	1,091	698
Money market funds
Assets:
Assets, fair value	50,433	71,175
Commercial paper
Assets:
Assets, fair value	16,882	31,935
U.S. government-sponsored agency bonds
Assets:
Assets, fair value	8,723
Corporate bonds
Assets:
Assets, fair value	999	7,022
Asset-backed securities
Assets:
Assets, fair value	1,000	5,304
Derivative liabilities for exit fees
Liabilities:
Liabilities, fair value	1,091	698
Level 1
Assets:
Assets, fair value	50,433	71,175
Liabilities:
Liabilities, fair value	0	0
Level 1 \| Money market funds
Assets:
Assets, fair value	50,433	71,175
Level 1 \| Commercial paper
Assets:
Assets, fair value	0	0
Level 1 \| U.S. government-sponsored agency bonds
Assets:
Assets, fair value	0
Level 1 \| Corporate bonds
Assets:
Assets, fair value	0	0
Level 1 \| Asset-backed securities
Assets:
Assets, fair value	0	0
Level 1 \| Derivative liabilities for exit fees
Liabilities:
Liabilities, fair value	0	0
Level 2
Assets:
Assets, fair value	27,604	44,261
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	16,882	31,935
Level 2 \| U.S. government-sponsored agency bonds
Assets:
Assets, fair value	8,723
Level 2 \| Corporate bonds
Assets:
Assets, fair value	999	7,022
Level 2 \| Asset-backed securities
Assets:
Assets, fair value	1,000	5,304
Level 2 \| Derivative liabilities for exit fees
Liabilities:
Liabilities, fair value	0	0
Level 3
Assets:
Assets, fair value	0	0
Liabilities:
Liabilities, fair value	1,091	698
Level 3 \| Money market funds
Assets:
Assets, fair value	0	0
Level 3 \| Commercial paper
Assets:
Assets, fair value	0	0
Level 3 \| U.S. government-sponsored agency bonds
Assets:
Assets, fair value	0
Level 3 \| Corporate bonds
Assets:
Assets, fair value	0	0
Level 3 \| Asset-backed securities
Assets:
Assets, fair value	0	0
Level 3 \| Derivative liabilities for exit fees
Liabilities:
Liabilities, fair value	$ 1,091	$ 698

Inventory - Schedule (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Inventory
Raw materials	$ 460
Work in process	3,606
Finished goods	463
Total	$ 4,529	$ 0

Inventory - Narrative (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Inventory Disclosure [Abstract]
Prepaid commercial manufacturing	$ 17,793	$ 9,406
Prepaid commercial manufacturing, noncurrent	$ 3,800

Product Revenue, Net - Narrative (Details) - USD ($)	3 Months Ended		6 Months Ended
Product Revenue, Net - Narrative (Details) - USD ($)	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Disaggregation of Revenue [Line Items]
Revenue	$ 2,526,000	$ 1,313,000	$ 2,994,000	$ 7,895,000
Contract with customer product sales gross to net accruals		0		0
Gross product revenue \| Customer \| Cardinal Health
Disaggregation of Revenue [Line Items]
Concentration risk (percent)	22.70%		21.70%
Gross product revenue \| Customer \| AmerisourceBergen Drug Corporation
Disaggregation of Revenue [Line Items]
Concentration risk (percent)	40.20%		35.10%
Gross product revenue \| Customer \| McKesson Corporation
Disaggregation of Revenue [Line Items]
Concentration risk (percent)	24.60%		22.50%
IBSRELA
Disaggregation of Revenue [Line Items]
Revenue	$ 1,600,000		$ 2,000,000
Product sales, net
Disaggregation of Revenue [Line Items]
Revenue	$ 1,564,000	$ 0	$ 2,014,000	$ 0

Product Revenue, Net - Gross-to-Net Sales Accruals (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2022 USD ($)
Gross-to-net sales accruals and reserves
Beginning balance	$ 0
Activity related to 2022 sales	735
Credits/deductions issued	(189)
Ending balance	546
Discounts and Chargebacks
Gross-to-net sales accruals and reserves
Beginning balance	0
Activity related to 2022 sales	84
Credits/deductions issued	(41)
Ending balance	43
Rebates
Gross-to-net sales accruals and reserves
Beginning balance	0
Activity related to 2022 sales	329
Credits/deductions issued	(15)
Ending balance	314
Other Fees, Copay and Returns
Gross-to-net sales accruals and reserves
Beginning balance	0
Activity related to 2022 sales	322
Credits/deductions issued	(133)
Ending balance	$ 189

Collaboration and Licensing Agreements - Narrative (Details) $ in Millions, ¥ in Billions	1 Months Ended					3 Months Ended		6 Months Ended			53 Months Ended
	Nov. 30, 2019 USD ($) segment item	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Nov. 30, 2017 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2022 CAD ($)	Jun. 30, 2021 USD ($)	Mar. 31, 2022 USD ($)	Jun. 30, 2022 JPY (¥)	Apr. 11, 2022 USD ($) payment_tranche
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue						$ 2,526,000	$ 1,313,000	$ 2,994,000		$ 7,895,000
Cost of revenue						138,000	0	223,000		1,000,000
License
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue						10,000	3,000	14,000		5,005,000
Product Supply Revenue
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue						952,000	0	966,000		126,000
2019 KKC Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue						0	1,300,000	0		2,800,000
2019 KKC Agreement \| KKC
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront license fees	$ 10,000,000
First installment of upfront license fees	$ 5,000,000
Term of payment of license fee, first installment	30 days
Second installment of upfront license fees	$ 5,000,000
Term of agreement	2 years
Number of amendments \| segment	3
2017 KKC Agreement \| License
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue						0	0	0		5,000,000	$ 10,000,000
2017 KKC Agreement \| Product Supply Revenue
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue						952,000	0	966,000		126,000
2017 KKC Agreement \| KKC
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront license fees				$ 30,000,000
Potential development milestones				$ 55,000,000
Potential commercialization milestones						62,300,000		62,300,000				¥ 8.5
Fee receivable for reduction in royalty rate													$ 40,000,000
Number of payment tranches for fee receivable for reduction in royalty rate \| payment_tranche													2
Fosun Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue						0	0	0		0
Fosun Agreement \| Fosun Pharma
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential development milestones						3,000,000		3,000,000
Upfront payment received			$ 12,000,000
Potential development and commercialization milestones								$ 113,000,000
Threshold percentage of net sales for tiered royalties								20.00%	20.00%
Knight Agreement \| Knight
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential development milestones						700,000		$ 700,000
Upfront payment received		$ 2,300,000
Potential development and commercialization milestones								17,200,000	$ 22.2
AZ Termination Agreement \| AstraZeneca
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					$ 75,000,000
Aggregate cost of revenue recognized						11,900,000		11,900,000
Aggregate amount paid						11,600,000		11,600,000
Cost of revenue						$ 200,000	$ 0	$ 300,000		$ 1,000,000
Minimum \| 2019 KKC Agreement \| KKC
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of separate collaborative agreements \| item	1

Collaboration and Licensing Agreements - Deferred Revenue (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Deferred revenue - non-current
Beginning balance	$ 4,727
Ending balance	12,421
2019 KKC Agreement
Deferred revenue - current
Beginning balance	0	$ 4,177
Decreases due to revenue recognized in the period for which cash has been received	0	(2,765)
Ending balance	0	1,412
2017 KKC Agreement
Deferred revenue - non-current
Beginning balance	4,727	0
Increases due to cash received during the period	3,829	2,947
Increases to amounts invoiced, for which cash has not yet been received	3,865	0
Ending balance	$ 12,421	$ 2,947

Deferred Royalty Obligation (Details) - Healthcare royalty partners IV, L.P - License - USD ($) $ in Millions		6 Months Ended
	Jun. 28, 2022	Jun. 30, 2022
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Royalty payments and commercial milestone payments	$ 20.0
Upfront payment	10.0	$ 10.0
Payment to be received	$ 5.0
Transaction costs		$ 0.4
Amortization, effective interest rate, percent		34.40%

Borrowing - Narrative (Details) - USD ($)		6 Months Ended
Borrowing - Narrative (Details) - USD ($)	Feb. 23, 2022	Jun. 30, 2022	May 31, 2018	May 16, 2018
Debt Instrument [Line Items]
Principal outstanding		$ 28,862,000
2018 Term Loan \| Term Loan
Debt Instrument [Line Items]
Term loan face amount				$ 50,000,000
Principal outstanding				$ 25,000,000
2022 Term Loan \| Term Loan
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 \| Term Loan \| Prior to first anniversary of closing date
Debt Instrument [Line Items]
Prepayment premium (as a percent)	3.00%
2022 Term Loan \| Term Loan \| After first anniversary through second anniversary of closing date
Debt Instrument [Line Items]
Prepayment premium (as a percent)	2.00%
2022 Term Loan \| Term Loan \| After second anniversary to maturity date
Debt Instrument [Line Items]
Prepayment premium (as a percent)	1.00%
2022 Term Loan \| Term Loan \| LIBOR
Debt Instrument [Line Items]
Floating per annum rate (percent)	7.95%
Addition to floating per annum rate (percent)	0.10%
Term Loan A \| Term Loan
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 \| Term Loan
Debt Instrument [Line Items]
Remaining funding based on milestone achievement	22,500,000
Future obligation upon loan funding or other events	$ 100,000
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
Exit fee, term (in years)	10 years

Borrowing - Future Payment Obligations (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Debt Disclosure [Abstract]
Total repayment obligations	$ 28,862
Less: Unamortized discount	(1,259)
Less: Unaccreted value of final fee	(1,230)
Long-term debt	26,373
Less: Current portion of long-term debt	(26,373)	$ (32,264)
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

Derivative Liability - Narrative (Details) - USD ($) $ in Millions	Feb. 23, 2022	Jun. 30, 2022	Dec. 31, 2021	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		$ 0.7	$ 0.7
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		$ 0.4
Exit fee (percent)	2.00%
Exit fee, net product revenue threshold	$ 100.0
2022 Exit Fee \| Level 3
Derivative [Line Items]
Fair value analysis, percentage change in probability of occurrence		10.00%

Derivative Liability - Changes in Fair Value (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
2018 Exit Fee
Change in Fair Value of Derivative Liability
Ending balance	$ 700
2022 Exit Fee
Change in Fair Value of Derivative Liability
Ending balance	400
Exit Fee derivative liability
Change in Fair Value of Derivative Liability
Beginning balance	698	$ 1,376
2022 Exit Fee addition at fair value	375	0
Ending balance	1,091	663
Exit Fee derivative liability \| 2018 Exit Fee
Change in Fair Value of Derivative Liability
Changes in estimated fair value	(29)	(713)
Exit Fee derivative liability \| 2022 Exit Fee
Change in Fair Value of Derivative Liability
Changes in estimated fair value	$ 47	$ 0

Leases - Additional Details of Facility Leases (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Right-of-use assets and lease liabilities
Right-of-use assets	$ 11,054	$ 12,752
Current portion of lease liabilities	3,691	3,492
Operating lease liability, net of current portion	7,857	9,748
Total operating lease liabilities	$ 11,548	$ 13,240
Additional details
Weighted-average remaining life (years)	2 years 10 months 24 days	3 years 4 months 24 days
Weighted-average discount rate	6.80%	6.90%

Leases - Lease Costs (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
Leases - Lease Costs (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Lease costs
Operating lease expense	$ 1,064	$ 837	$ 2,128	$ 1,510
Cash paid for operating lease	$ 1,064	$ 766	$ 2,122	$ 1,554

Leases - Undiscounted Cash Payment Obligations (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Undiscounted cash payment obligations
Remainder of 2022	$ 2,170
2023	4,440
2024	4,589
2025	1,321
2026	252
Total undiscounted operating lease payments	12,772
Imputed interest expenses	(1,224)
Total operating lease liabilities	11,548	$ 13,240
Less: Current portion of operating lease liability	(3,691)	(3,492)
Operating lease liability, net of current portion	$ 7,857	$ 9,748

Stockholders' Equity (Details) - USD ($) $ / shares in Units, shares in Millions	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Aug. 31, 2021	Jul. 31, 2020
Subsidiary, Sale of Stock [Line Items]
Proceeds from issuance of common stock in at the market offering, net of issuance costs	$ 18,478,000	$ 62,446,000
Common stock
Subsidiary, Sale of Stock [Line Items]
Maximum aggregate offering price				$ 250,000,000
2020 Open Market Sales Agreement
Subsidiary, Sale of Stock [Line Items]
Issuance of common stock in at the market offering (in shares)		9.0
Proceeds from issuance of common stock in at the market offering, net of issuance costs		$ 63,800,000
Weighted-average sales price per share (in dollars per share)		$ 7.10
2020 Open Market Sales Agreement \| Common stock
Subsidiary, Sale of Stock [Line Items]
Maximum aggregate offering price				$ 100,000,000
2021 Open Market Sales Agreement
Subsidiary, Sale of Stock [Line Items]
Issuance of common stock in at the market offering (in shares)	20.5
Proceeds from issuance of common stock in at the market offering, net of issuance costs	$ 18,900,000
Weighted-average sales price per share (in dollars per share)	$ 0.92
Commission on sale of stock per agreement (percent)	3.00%
2021 Open Market Sales Agreement \| Common stock
Subsidiary, Sale of Stock [Line Items]
Maximum aggregate offering price			$ 150,000,000

Equity Incentive Plans - Stock-Based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Stock-based Compensation [Line Items]
Stock-based compensation expense	$ 3,193	$ 3,219	$ 6,824	$ 6,306
Selling, general and administrative
Stock-based Compensation [Line Items]
Stock-based compensation expense	2,220	2,132	4,728	4,127
Research and development
Stock-based Compensation [Line Items]
Stock-based compensation expense	$ 973	$ 1,087	$ 2,096	$ 2,179

Equity Incentive Plans - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	6 Months Ended
	Feb. 28, 2022	Jun. 30, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation benefits		$ 0.2
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)	100,000
Purchase price (in dollars per share)	$ 0.65
Proceeds from ESPP	$ 0.1

Equity Incentive Plans - Unrecognized Stock-Based Compensation (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2022 USD ($)
Options to purchase common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized Compensation Expense	$ 13,096
Average Remaining Vesting Period (Years)	2 years 8 months 12 days
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized Compensation Expense	$ 3,524
Average Remaining Vesting Period (Years)	2 years 10 months 24 days
ESPP shares issuable
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized Compensation Expense	$ 21
Average Remaining Vesting Period (Years)	2 months 12 days

Equity Incentive Plans - Stock Options (Details)	6 Months Ended
Equity Incentive Plans - Stock Options (Details)	Jun. 30, 2022 $ / shares shares
Number of Shares
Options outstanding balance, beginning (in shares) \| shares	10,417,000
Options granted (in shares) \| shares	4,773,000
Options exercised (in shares) \| shares	0
Options forfeited or canceled (in shares) \| shares	(1,190,000)
Options outstanding balance, ending (in shares) \| shares	14,000,000
Options exercisable (in shares) \| shares	7,085,000
Weighted-Average Exercise Price per Share
Options outstanding balance, beginning (in dollars per share) \| $ / shares	$ 7.00
Options granted (in dollars per share) \| $ / shares	0.88
Options exercised (in dollars per share) \| $ / shares	0
Options forfeited (in dollars per share) \| $ / shares	7.04
Options outstanding balance, ending (in dollars per share) \| $ / shares	4.91
Options exercisable (in dollars per share) \| $ / shares	$ 6.91

Equity Incentive Plans - Restricted Stock Units (Details) - Restricted stock units	6 Months Ended
	Jun. 30, 2022 $ / shares shares
Number of RSUs
Outstanding balance, beginning (in shares) \| shares	3,529,000
Granted (in shares) \| shares	1,980,000
Vested (in shares) \| shares	(3,714,000)
Forfeited (in shares) \| shares	(121,000)
Outstanding balance, ending (in shares) \| shares	1,674,000
Weighted-Average Grant Date Fair Value Per Share
Outstanding balance, beginning (in dollars per share) \| $ / shares	$ 2.04
Granted (in dollars per share) \| $ / shares	0.81
Vested (in dollars per share) \| $ / shares	1.26
Forfeited (in dollars per share) \| $ / shares	2.85
Outstanding balance, ending (in dollars per share) \| $ / shares	$ 2.26

Net Loss Per Share - Computation of Net Loss Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Numerator:
Net loss	$ (26,938)	$ (45,189)	$ (55,009)	$ (78,344)
Denominator:
Weighted average common shares outstanding - basic (in shares)	145,544,372	100,040,083	138,279,945	98,617,564
Weighted average common shares outstanding - diluted (in shares)	145,544,372	100,040,083	138,279,945	98,617,564
Net loss per share - basic (in dollars per share)	$ (0.19)	$ (0.45)	$ (0.40)	$ (0.79)
Net loss per share - diluted (in dollars per share)	$ (0.19)	$ (0.45)	$ (0.40)	$ (0.79)

- Definition

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

+ References

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-Name Accounting Standards Codification
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+ Details

- Definition

The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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+ Details

- Definition

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

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+ Details

Net Loss Per Share - Summary of Anti Dilutive Securities Excluded from Computation of Diluted Net Loss Per Share (Details) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (in shares)	16,819	13,802	17,321	13,406
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)	13,099	12,447	13,182	12,211
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)	3,520	1,125	3,963	1,006
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)	200	230	176	188

Contingencies (Details) - USD ($)	Jun. 30, 2022	Jun. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Contingent liabilities	$ 0	$ 0