0001438533-21-000053 | 10-Q | XBRL Viewer

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Cover Page - shares	9 Months Ended
Cover Page - shares	Sep. 30, 2021	Oct. 26, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2021
Document Transition Report	false
Entity File Number	001-36257
Entity Registrant Name	TRAVERE THERAPEUTICS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	27-4842691
Entity Address, Address Line One	3611 Valley Centre Drive
Entity Address, Address Line Two	Suite 300
Entity Address, City or Town	San Diego
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92130
City Area Code	888
Local Phone Number	969-7879
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Trading Symbol	TVTX
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		61,226,392
Entity Central Index Key	0001438533
Current Fiscal Year End Date	--12-31
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 150,327	$ 84,772
Available-for-sale debt securities, at fair value (amortized cost $400,866, allowance for credit losses of $0 as of September 30, 2021; amortized cost $276,111, allowance for credit losses of $0 as of December 31, 2020)	400,857	276,817
Accounts receivable, net	13,370	15,925
Inventory, net	6,616	7,608
Prepaid expenses and other current assets	7,504	8,143
Tax receivable	405	17,142
Total current assets	579,079	410,407
Property and equipment, net	11,513	9,418
Other non-current assets	34,871	33,489
Intangible assets, net	148,676	153,189
Goodwill	936	936
Total assets	775,075	607,439
Current liabilities:
Accounts payable	5,830	12,133
Accrued expenses	63,308	56,793
Other current liabilities	10,056	6,334
Deferred revenue, current portion	16,069	0
Business combination-related contingent consideration, current portion	17,900	17,400
Total current liabilities	113,163	92,660
Convertible debt	223,696	215,339
Other non-current liabilities	43,262	40,527
Deferred revenue, less current portion	24,084	0
Business combination-related contingent consideration, less current portion	63,500	47,700
Total liabilities	467,705	396,226
Stockholders' Equity:
Preferred stock $0.0001 par value; 20,000,000 shares authorized; 0 issued and outstanding as of September 30, 2021 and December 31, 2020	0	0
Common stock $0.0001 par value; 200,000,000 and 100,000,000 shares authorized; 61,018,229 and 52,248,431 issued and outstanding as of September 30, 2021 and December 31, 2020, respectively	6	5
Additional paid-in capital	1,022,282	797,985
Accumulated deficit	(714,393)	(585,875)
Accumulated other comprehensive loss	(525)	(902)
Total stockholders' equity	307,370	211,213
Total liabilities and stockholders' equity	$ 775,075	$ 607,439

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Available-for-sale debt securities, amortized cost	$ 400,866	$ 276,111
Available-for-sale debt securities, allowance for credit losses	$ 0	$ 0
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	20,000,000	20,000,000
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)	200,000,000	100,000,000
Common stock shares issued (in shares)	61,018,229	52,248,431
Common stock shares outstanding (in shares)	61,018,229	52,248,431

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Total revenue	$ 68,217	$ 51,139	$ 170,241	$ 147,338
Operating expenses:
Cost of goods sold	1,592	1,189	4,888	4,054
Research and development	48,407	32,349	148,160	93,387
Selling, general and administrative	36,065	31,951	107,808	100,061
Change in fair value of contingent consideration	13,864	5,085	23,960	7,448
Total operating expenses	99,928	70,574	284,816	204,950
Operating loss	(31,711)	(19,435)	(114,575)	(57,612)
Other income (expenses), net:
Other income (expense), net	654	553	(223)	788
Interest income	360	1,123	1,757	4,414
Interest expense	(4,899)	(4,767)	(15,072)	(14,287)
Total other expense, net	(3,885)	(3,091)	(13,538)	(9,085)
Loss before income taxes	(35,596)	(22,526)	(128,113)	(66,697)
Income tax (expense) benefit	(43)	(23)	(405)	18,888
Net loss	$ (35,639)	$ (22,549)	$ (128,518)	$ (47,809)
Basic net loss per common share (in dollars per share)	$ (0.59)	$ (0.44)	$ (2.17)	$ (1.03)
Diluted net loss per common share (in dollars per share)	$ (0.59)	$ (0.44)	$ (2.17)	$ (1.03)
Basic weighted average common shares outstanding (in shares)	60,803,045	50,929,575	59,230,881	46,289,103
Diluted weighted average common shares outstanding (in shares)	60,803,045	50,929,575	59,230,881	46,289,103
Comprehensive loss:
Net loss	$ (35,639)	$ (22,549)	$ (128,518)	$ (47,809)
Foreign currency translation	216	(564)	1,091	(620)
Unrealized gain (loss) on debt securities	(100)	(480)	(714)	250
Comprehensive loss	(35,523)	(23,593)	(128,141)	(48,179)
Net product sales
Total revenue	54,174	51,139	156,198	147,338
License revenue
Total revenue	$ 14,043	$ 0	$ 14,043	$ 0

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash Flows From Operating Activities:
Net loss	$ (128,518)	$ (47,809)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	20,567	17,946
Non-cash interest expense	1,097	1,285
Amortization of discounts/premiums on investments, net	1,311	530
Amortization of debt discount and issuance costs	8,356	7,789
Provision for inventory	1,372	1,317
Share-based compensation	21,524	16,613
ESPP expense	666	649
Change in fair value of contingent consideration	23,960	7,448
Payments related to change in fair value of contingent consideration	(5,675)	(10,268)
Other	2,620	563
Changes in operating assets and liabilities:
Accounts receivable	2,577	3,195
Inventory	(380)	(3,813)
Tax receivable	17,006	(12,220)
Other current and non-current operating assets	(2,045)	(20,181)
Change in lease assets and liabilities, net	5,823	0
Accounts payable and accrued expenses	1,908	(10,213)
Deferred revenue, current and non-current	40,153	0
Other current and non-current operating liabilities	(237)	18,296
Net cash provided by (used in) operating activities	12,085	(28,873)
Cash Flows From Investing Activities:
Purchase of fixed assets	(4,947)	(2,926)
Cash paid for intangible assets	(14,004)	(13,039)
Proceeds from the sale/maturity of debt securities	376,099	223,152
Purchase of debt securities	(502,141)	(143,003)
Net cash provided by (used in) investing activities	(144,993)	64,184
Cash Flows From Financing Activities:
Payment of acquisition-related contingent consideration	(2,065)	(6,886)
Payment of guaranteed minimum royalty	(1,575)	(1,575)
Proceeds from exercise of stock options	6,679	1,345
Proceeds from issuances under employee stock purchase plan	1,275	1,098
Net cash provided by financing activities	198,470	102,674
Effect of exchange rate changes on cash	(7)	60
Net change in cash and cash equivalents	65,555	138,045
Cash and cash equivalents, beginning of year	84,772	62,436
Cash and cash equivalents, end of period	150,327	200,481
At-The-Market Offering
Cash Flows From Financing Activities:
Proceeds from issuance of common stock	4,878	0
Underwritten Equity Offering
Cash Flows From Financing Activities:
Proceeds from issuance of common stock	$ 189,278	$ 108,692

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2019		43,088,921
Beginning balance at Dec. 31, 2019	$ 221,196	$ 4	$ 636,910	$ 726	$ (416,444)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share based compensation	16,613		16,613
Issuance of common stock under the equity incentive plan and proceeds from exercise (in shares)		361,722
Issuance of common stock under the equity incentive plan and proceeds from exercise	1,345		1,345
Equity offering (in shares)		7,475,000
Equity offering, net of issuance costs	108,692	$ 1	108,691
Unrealized gain (loss) on debt securities	250			250
Foreign currency translation adjustments	(622)			(622)
ESPP stock purchase and expense (in shares)		97,544
ESPP stock purchase and expense	1,748		1,748
Net loss	(47,809)				(47,809)
Ending balance (in shares) at Sep. 30, 2020		51,023,187
Ending balance at Sep. 30, 2020	301,413	$ 5	765,307	354	(464,253)
Beginning balance (in shares) at Jun. 30, 2020		50,902,874
Beginning balance at Jun. 30, 2020	318,645	$ 5	758,945	1,399	(441,704)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share based compensation	5,139		5,139
Issuance of common stock under the equity incentive plan and proceeds from exercise (in shares)		120,313
Issuance of common stock under the equity incentive plan and proceeds from exercise	914		914
Equity offering, net of issuance costs	48		48
Unrealized gain (loss) on debt securities	(479)			(479)
Foreign currency translation adjustments	(566)			(566)
ESPP stock purchase and expense (in shares)
ESPP stock purchase and expense	261		261
Net loss	(22,549)				(22,549)
Ending balance (in shares) at Sep. 30, 2020		51,023,187
Ending balance at Sep. 30, 2020	301,413	$ 5	765,307	354	(464,253)
Beginning balance (in shares) at Dec. 31, 2020		52,248,431
Beginning balance at Dec. 31, 2020	211,213	$ 5	797,985	(902)	(585,875)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share based compensation	21,524		21,524
Issuance of common stock under the equity incentive plan and proceeds from exercise (in shares)		954,225
Issuance of common stock under the equity incentive plan and proceeds from exercise	6,679		6,679
Equity offering (in shares)		7,716,686
Equity offering, net of issuance costs	194,157	$ 1	194,156
Unrealized gain (loss) on debt securities	(714)			(714)
Foreign currency translation adjustments	1,091			1,091
ESPP stock purchase and expense (in shares)		98,887
ESPP stock purchase and expense	1,938		1,938
Net loss	(128,518)				(128,518)
Ending balance (in shares) at Sep. 30, 2021		61,018,229
Ending balance at Sep. 30, 2021	307,370	$ 6	1,022,282	(525)	(714,393)
Beginning balance (in shares) at Jun. 30, 2021		60,710,876
Beginning balance at Jun. 30, 2021	332,303	$ 6	1,011,692	(641)	(678,754)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share based compensation	6,757		6,757
Issuance of common stock under the equity incentive plan and proceeds from exercise (in shares)		307,353
Issuance of common stock under the equity incentive plan and proceeds from exercise	3,605		3,605
Equity offering, net of issuance costs	0
Unrealized gain (loss) on debt securities	(100)			(100)
Foreign currency translation adjustments	216			216
ESPP stock purchase and expense	228		228
Net loss	(35,639)				(35,639)
Ending balance (in shares) at Sep. 30, 2021		61,018,229
Ending balance at Sep. 30, 2021	$ 307,370	$ 6	$ 1,022,282	$ (525)	$ (714,393)

DESCRIPTION OF BUSINESS	9 Months Ended
DESCRIPTION OF BUSINESS	Sep. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
DESCRIPTION OF BUSINESS	DESCRIPTION OF BUSINESS Organization and Description of Business Travere Therapeutics, Inc. (“we”, “our”, “us”, “Travere” and the “Company”) refers to Travere Therapeutics, Inc., a Delaware corporation, as well as our direct and indirect subsidiaries. Travere is a fully integrated biopharmaceutical company headquartered in San Diego, California focused on identifying, developing and delivering life-changing therapies to people with rare diseases. We regularly evaluate and, where appropriate, act on opportunities to expand our product pipeline through licenses and acquisitions of products in areas that will serve patients with serious or rare diseases and that we believe offer attractive growth characteristics. The ongoing novel coronavirus (COVID-19) pandemic has resulted in travel restrictions, quarantines, “stay-at-home” and “shelter-in-place” orders and extended shutdown of certain businesses around the world. While the impact of the COVID-19 pandemic did not have a material adverse effect on our financial position or results of operations for the nine months ended September 30, 2021, these governmental actions and similar actions that may be enacted in the future, and the widespread economic disruption arising from the pandemic, have the potential to materially impact our business and influence our business decisions. The extent and duration of the pandemic is unknown, and the future effects on our business are uncertain and difficult to predict. The Company is continuing to monitor the events and circumstances surrounding the COVID-19 pandemic, which may require adjustments to the Company’s estimates and assumptions in the future. Clinical Programs: Sparsentan, also known as RE-021, is an investigational product candidate with a dual mechanism of action, selective endothelin receptor antagonist (“ERA”), with in vitro selectivity toward endothelin receptor type A, and a potent angiotensin receptor blocker (“ARB”). Sparsentan is currently being evaluated in two pivotal Phase 3 clinical studies in the following indications: •Focal segmental glomerulosclerosis ("FSGS") is a rare kidney disease characterized by proteinuria where the glomeruli become progressively scarred. FSGS is a leading cause of end-stage renal disease. •Immunoglobulin A nephropathy ("IgAN") is an immune-complex-mediated glomerulonephritis characterized by hematuria, proteinuria, and variable rates of progressive renal failure. IgAN is the most common primary glomerular disease. Pegtibatinase (TVT-058) is a novel investigational human enzyme replacement candidate being evaluated for the treatment of classical homocystinuria (HCU). Classical HCU is a rare metabolic disorder characterized by elevated levels of plasma homocysteine that can lead to vision, skeletal, circulatory and central nervous system issues. Pegtibatinase (TVT-058) is currently being tested in a Phase 1/2 double blind, randomized, placebo-controlled dose escalation study to assess its safety, tolerability, pharmacokinetics, pharmacodynamics and clinical effects in patients with classical HCU. Pegtibatinase (TVT-058) has been granted Rare Pediatric Disease and Fast Track designations by the U.S. Food and Drug Administration ("FDA"), as well as orphan drug designation in the United States and Europe. We acquired pegtibatinase (TVT-058) as part of the November 2020 acquisition of Orphan Technologies Limited. Chenodal (chenodeoxycholic acid or CDCA) is a naturally occurring bile acid that is approved for the treatment of people with radiolucent stones in the gallbladder. CTX is a rare, progressive and underdiagnosed bile acid synthesis disorder affecting many parts of the body. In January 2020, we randomized the first patients in our Phase 3 RESTORE Study to evaluate the effects of Chenodal in adult and pediatric patients with CTX, and the study enrollment remains open. The pivotal study is intended to support an NDA submission for marketing authorization of Chenodal for CTX in the United States. Preclinical Programs: The Company is a participant in two Cooperative Research and Development Agreements ("CRADAs"), which form a multi-stakeholder approach to pool resources with leading experts, and incorporate the patient perspective early in the therapeutic identification and development process. We have partnered with the National Institutes of Health’s National Center for Advancing Translational Sciences ("NCATS") and leading patient advocacy organizations, CDG Care and Alagille Syndrome Alliance, aimed at the identification of potential small molecule therapeutics for NGLY1 deficiency and Alagille syndrome, respectively. There are no treatment options currently approved for these diseases. Approved products: •Chenodal (chenodiol tablets) is approved in the United States for the treatment of patients suffering from gallstones in whom surgery poses an unacceptable health risk due to disease or advanced age. •Cholbam® (cholic acid capsules) is approved in the United States for the treatment of bile acid synthesis disorders due to single enzyme defects and is further indicated for adjunctive treatment of patients with peroxisomal disorders. •Thiola® and Thiola EC® (tiopronin tablets) are approved in the United States for the prevention of cystine (kidney) stone formation in patients with severe homozygous cystinuria.

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES	BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES The accompanying unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto included in the 2020 10-K filed with the SEC on March 1, 2021. The accompanying condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) for interim financial information, the instructions for Form 10-Q and the rules and regulations of the SEC. Accordingly, since they are interim statements, the accompanying condensed consolidated financial statements do not include all of the information and notes required by GAAP for annual financial statements, but reflect all adjustments consisting of normal, recurring adjustments, that are necessary for a fair statement of the financial position, results of operations and cash flows for the interim periods presented. Interim results are not necessarily indicative of the results that may be expected for any future periods. The December 31, 2020 balance sheet information was derived from the audited financial statements as of that date. A summary of the significant accounting policies applied in the preparation of the accompanying condensed consolidated financial statements follows: Principles of Consolidation The unaudited condensed consolidated financial statements represent the consolidation of the accounts of the Company and its subsidiaries in conformity with GAAP. All intercompany accounts and transactions have been eliminated in consolidation. Revenue Recognition The Company recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of Accounting Standards Codification ("ASC") 606, Revenue from Contracts with Customers ("ASC 606"), the entity performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. The Company only applies the five-step model to contracts when it is probable that the entity will collect substantially all the consideration it is entitled to in exchange for the goods or services it transfers to the customer. See Note 3 and Note 4 for further discussion. Payments received under collaboration and licensing agreements may include non-refundable fees at the inception of the arrangements, milestone payments for specific achievements and royalties on the sale of products. At the inception of arrangements that include milestone payments, the Company uses judgement to evaluate whether the milestones are probable of being achieved and estimates the amount to include in the transaction price utilizing the most likely amount method. If it is probable that a significant revenue reversal will not occur, the estimated amount is included in the transaction price. Milestone payments that are not within the Company or the licensee’s control, such as regulatory approvals are not included in the transaction price until those approvals are received. At the end of each reporting period, the Company re-evaluates the probability of achievement of development milestones and any related constraint and adjusts the estimate of the overall transaction price, if necessary. The Company recognizes aggregate sales-based milestones and royalty payments from product sales at the later of when the related sales occur or when the performance obligation to which the sales-based milestone or royalty has been allocated has been satisfied. If it is probable that a significant revenue reversal will not occur, the Company estimates the sales-based milestone and royalty payments using the most likely amount method. The Company utilizes significant judgement to develop estimates of the stand-alone selling price for each distinct performance obligation based upon the relative stand-alone selling price. Variable consideration that relates specifically to the Company’s efforts to satisfy specific performance obligations is allocated entirely to those performance obligations. The stand-alone selling price for license-related performance obligations requires judgement in developing assumptions to project probability-weighted cash flows based upon estimates of forecasted revenues, clinical and regulatory timelines and discount rates. The stand-alone selling price for clinical development performance obligations is based on forecasted expected costs of satisfying a performance obligation plus an appropriate margin. If the licenses to intellectual property are determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenues from non-refundable, upfront fees allocated to the license when the license is transferred to the licensee and the licensee is able to benefit from the license. For licenses that are not distinct from other promises, the Company applies judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue from non-refundable, upfront fees. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the related revenue recognition accordingly. The selection of the method to measure progress towards completion requires judgment and is based on the nature of the products or services to be provided. Revenue is recorded proportionally as costs are incurred. The Company generally utilizes the cost-to-cost method of progress because it best measures the transfer of control to the customer which occurs as the Company incurs costs. Under the cost-to-cost measure of progress, the extent of progress towards completion is measured based on the ratio of costs incurred to date to the total estimated costs at completion of the performance obligation. The Company uses judgment to estimate the total costs expected to complete the clinical development performance obligations, which include subcontractor costs, labor, materials, other direct costs and an allocation of indirect costs. The Company evaluates these cost estimates and the progress each reporting period and adjusts the measure of progress, if necessary. Research and Development Expenses Research and development expenses are comprised of salaries and bonuses, benefits, non-cash share-based compensation, license fees, costs paid to third-party contractors to perform research, conduct clinical trials and pre/non-clinical trials, develop drug materials, and associated overhead expenses and facilities. We also incur indirect costs that are not allocated to specific programs because such costs benefit multiple development programs and allow us to increase our pharmaceutical development capabilities. These consist of internal shared resources related to the development and maintenance of systems and processes applicable to all of our programs. Clinical Trial Expenses Our clinical trials are conducted pursuant to contracts with contract research organizations ("CROs") that support conducting and managing clinical trials. The financial terms and activities of these agreements vary from contract to contract and may result in uneven expense levels. Generally, these agreements set forth activities that drive the recording of expenses such as start-up, initiation activities, enrollment, treatment of patients, or the completion of other clinical trial activities. Expenses related to clinical trials are accrued based on our estimates and/or representations from service providers regarding work performed, including actual level of patient enrollment, completion of patient studies and progress of the clinical trials. Other incidental costs related to patient enrollment or treatment are accrued when reasonably certain. If the amounts we are obligated to pay under our clinical trial agreements are modified (for instance, as a result of changes in the clinical trial protocol or scope of work to be performed), we adjust our accruals accordingly on a prospective basis. Revisions to our contractual payment obligations are charged to expense in the period in which the facts that give rise to the revision become reasonably certain. We currently have three Phase 3 clinical trials in process that are in varying stages of activity, with ongoing non-clinical support trials. As such, clinical trial expenses will vary depending on all the factors set forth above and may fluctuate significantly from quarter to quarter. Intangible Assets with Cost Accumulation Model In 2014, the Company entered into a license agreement with Mission Pharmacal in which the Company obtained the exclusive right to license the trademark of Thiola. The acquisition of the Thiola license qualified as an asset acquisition under the principles of ASC 805 in effect at the time of acquisition. The license agreement requires the Company to make royalty payments based on net sales of Thiola. The liability for royalties in excess of the annual contractual minimum is recognized in the period in which the royalties become probable and estimable, which is typically in the period corresponding with the respective sales. The Company records an offsetting increase to the cost basis of the asset under the cost accumulation model. The additional cost basis is subsequently amortized over the remaining life of the license agreement. Consistent with all prior periods since Thiola was acquired, the Company has not accrued any liability for royalties in excess of the annual contractual minimum at September 30, 2021, as such royalties are not yet probable and estimable. Recently Issued Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board ("FASB") or other standard setting bodies. Unless otherwise discussed, the Company believes that the impact of recently issued standards that are not yet effective will not have a material impact on its consolidated financial position or results of operations upon adoption. In August 2020, the FASB issued ASU No. 2020-06, Accounting for Convertible Instruments and Contracts in an Entity's Own Equity. The ASU includes amendments to the guidance on convertible instruments and the derivative scope exception for contracts in an entity's own equity and simplifies the accounting for convertible instruments which include beneficial conversion features or cash conversion features by removing certain separation models in Subtopic 470-20. Additionally, the ASU will require entities to use the "if-converted" method when calculating diluted earnings per share for convertible instruments. The ASU is effective for fiscal years beginning after December 15, 2021, including interim periods within those fiscal years. The Company's assessment of the impact of the new standard on the Company's financial statements is ongoing.

REVENUE RECOGNITION

9 Months Ended

Sep. 30, 2021

Revenue from Contract with Customer [Abstract]

REVENUE RECOGNITION

Product Sales, Net

Product sales consist of Bile Acid products (Chenodal and Cholbam) and Tiopronin products (Thiola and Thiola EC). The Company sells its products through direct-to-patient distributors worldwide, with more than 99% of the revenue generated in North America.

Revenues from product sales are recognized when the customer obtains control of the Company’s product, which occurs upon delivery to the customer. The Company receives payments from its product sales based on terms that generally are within 30 days of delivery of product to the patient.

Deductions from Revenue

Revenues from product sales are recorded at the net sales price, which includes provisions resulting from discounts, rebates and co-pay assistance that are offered to customers, health care providers, payors and other indirect customers relating to the Company’s sales of its products. These provisions are based on the amounts earned or to be claimed on the related sales and are classified as a reduction of accounts receivable (if the amount is payable to a customer) or as a current liability (if the amount is payable to a party other than a customer). Where appropriate, these reserves take into consideration the Company’s historical experience, current contractual and statutory requirements and specific known market events and trends. Overall, these reserves reflect the Company’s best estimates of the amount of consideration to which it is entitled based on the terms of the contract. If actual results in the future vary from the Company’s provisions, the Company will adjust the provision, which would affect net product revenue and earnings in the period such variances become known. Our historical experience is that such adjustments have been immaterial.

Government Rebates: We calculate the rebates that we will be obligated to provide to government programs and deduct these estimated amounts from our gross product sales at the time the revenues are recognized. Allowances for government rebates and discounts are established based on actual payer information, which is reasonably estimated at the time of delivery, and the government-mandated discounts applicable to government-funded programs. Rebate discounts are included in other current liabilities in the accompanying consolidated balance sheets.

Commercial Rebates: We calculate the rebates that we incur due to contracts with certain commercial payors and deduct these amounts from our gross product sales at the time the revenues are recognized. Allowances for commercial rebates are established based on actual payer information, which is reasonably estimated at the time of delivery. Rebate discounts are included in other current liabilities in the accompanying consolidated balance sheets.

Prompt Pay Discounts: We offer discounts to certain customers for prompt payments. We accrue for the calculated prompt pay discount based on the gross amount of each invoice for those customers at the time of sale.

Product Returns: Consistent with industry practice, we offer our customers a limited right to return product purchased directly from the Company, which is principally based upon the product’s expiration date. Generally, shipments are only made upon a patient prescription thus returns are minimal.

Co-pay Assistance: We offer a co-pay assistance program, which is intended to provide financial assistance to qualified commercially insured patients with prescription drug co-payments required by payors. The calculation of the accrual for co-pay assistance is based on an identification of claims and the cost per claim associated with product that has been recognized as revenue.

The following table summarizes net product sales for the three and nine months ended September 30, 2021 and 2020 (in thousands):


	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Bile acid products	$	24,353	$	22,912	$	71,291	$	66,766
Tiopronin products	29,821		28,227		84,907		80,572
Total net product sales	$	54,174	$	51,139	$	156,198	$	147,338

- 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 http://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 http://asc.fasb.org/extlink&oid=123351226&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 http://asc.fasb.org/extlink&oid=123351226&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 http://asc.fasb.org/extlink&oid=123351226&loc=SL49130554-203045

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130550-203045

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=123351226&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 http://asc.fasb.org/extlink&oid=123351226&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 http://asc.fasb.org/extlink&oid=123351226&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 http://asc.fasb.org/extlink&oid=123351226&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 http://asc.fasb.org/extlink&oid=123351226&loc=SL49130554-203045

+ Details

COLLABORATION AND LICENSE AGREEMENTS	9 Months Ended
COLLABORATION AND LICENSE AGREEMENTS	Sep. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
COLLABORATION AND LICENSE AGREEMENTS	COLLABORATION AND LICENSE AGREEMENTS On September 15, 2021, the Company entered into a license and collaboration agreement (“License Agreement”) with Vifor (International) Ltd. (“Vifor Pharma”), pursuant to which the Company granted an exclusive license to Vifor Pharma for the commercialization of sparsentan in Europe, Australia and New Zealand ("Licensed Territories"). Vifor Pharma also has first right of negotiation to expand the licensed territories into Canada, China, Brazil and/ or Mexico. Under the terms of the License Agreement, the Company received an upfront payment of $55.0 million and will be eligible for up to $135.0 million in aggregate regulatory and market access related milestone payments and up to $655.0 million in aggregate sales-based milestone payments for a total potential value of up to $845.0 million. The Company is also entitled to receive tiered double-digit royalties of up to 40 percent of annual net sales of sparsentan in the Licensed Territories. Under the License Agreement, Vifor Pharma will be responsible for all commercialization activities in the Licensed Territories. The Company remains responsible for the worldwide clinical development of sparsentan through regulatory approval as defined and will retain all rights to sparsentan in the United States and rest of world outside of the Licensed Territories. Development costs for any post regulatory approval development activities, subject to approval by both parties, will be borne by the Company and Vifor Pharma as defined, respectively. The License Agreement will remain in effect, unless terminated earlier, until the expiration of all royalty terms for sparsentan in the licensed territories. Each party has the right to terminate the License Agreement for the other party’s uncured material breach, insolvency or if the time required for performance under the License Agreement by the other party is extended due to a force majeure event that continues for six months or more. The Company assessed the License Agreement and determined that it meets both criteria to be considered a collaborative agreement within the Scope of ASC 808, Collaborative Arrangements of active participation by both parties and exposures to significant risks and rewards dependent on the commercial success of the activities. Both parties participate on joint steering and other committees overseeing the collaboration activities. Also, both parties are exposed to significant risks and rewards based on the economic outcomes of regulatory approvals and commercialization of sparsentan. The Company determined the transaction price under the License Agreement totaled $55.0 million, consisting of the fixed non-refundable upfront payment. The variable regulatory and access related milestones were excluded from the transaction price given the substantial uncertainty related to their achievement. Sales-based milestone payments and royalties on net sales were excluded from the transaction price and will be recognized at the later of when the related sales occur or when the performance obligation to which the sales-based milestone or royalty has been allocated have been satisfied. The Company concluded that Vifor Pharma represented a customer and applied relevant guidance from ASC 606 to evaluate the accounting under the License Agreement. In accordance with this guidance, the Company concluded that the promise to grant the license is distinct from the promise to provide clinical development services resulting in two performance obligations. As a result, the Company allocated $13.0 million of the transaction price, based on the performance obligations' relative standalone selling prices, to the license, which was recorded as License Revenue for the three and nine months ended September 30, 2021. The remaining $42.0 million of the transaction price was allocated to the clinical development activities and recorded as deferred revenue, which will be recognized over the development period based upon the ratio of costs incurred to date to the total estimated costs. The Company recognized $1.0 million in License Revenue based upon the ratio of costs incurred to total estimated costs for the three and nine months ended September 30, 2021. Deferred revenue related to the clinical development activities as of September 30, 2021 was $40.2 million. Of this amount, $16.1 million was classified as current as of September 30, 2021, based upon amounts expected to be realized within the next year.

DEBT SECURITIES

9 Months Ended

Sep. 30, 2021

Investments, Debt and Equity Securities [Abstract]

DEBT SECURITIES

DEBT SECURITIESThe Company's debt securities as of September 30, 2021 and December 31, 2020 were comprised of available-for-sale corporate and government debt securities. These securities are carried at fair value, with the unrealized gains and losses reported in accumulated other comprehensive income (loss), unless an impairment is determined to be the result of credit-related factors or the Company intends to sell the security or it is more likely than not that the Company

will be required to sell the security before recovery. The amortized cost of debt securities is adjusted for amortization of premiums and accretion of discounts to maturity. Such amortization and accretion is included in interest income. Realized gains and losses and declines in value that are determined to be the result of credit losses, if any, on available-for-sale securities are included in other income or expense. Unrealized losses that are determined to be credit-related are also recorded as an allowance against the amortized cost basis. The cost of securities sold is based on the specific identification method. Interest and dividends on securities classified as available-for-sale are included in interest income. All available-for-sale securities are classified as current assets, even if the maturity when acquired by the Company is greater than one year due to the ability to liquidate within the next 12 months.

During the nine months ended September 30, 2021, investment activity for the Company included $376.1 million in maturities and $502.1 million in purchases, all relating to debt based marketable securities.

Debt securities consisted of the following (in thousands):


	September 30, 2021		December 31, 2020
Commercial paper	$	148,874	$	135,145
Corporate debt securities	227,530		98,646
Securities of government sponsored entities	24,453		43,026
Total debt securities	$	400,857	$	276,817

The following is a summary of short-term debt securities classified as available-for-sale as of September 30, 2021 (in thousands):


	Remaining Contractual Maturity (in years)	Amortized Cost		Unrealized Gains		Unrealized Losses		Aggregate Estimated Fair Value
Commercial paper	Less than 1	$	148,886	$	10	$	(22)	$	148,874
Corporate debt securities	Less than 1	131,598		62		(25)		131,635
Securities of government-sponsored entities	Less than 1	21,966		1		(11)		21,956
Total maturity less than 1 year		302,450		73		(58)		302,465
Corporate debt securities	1 to 2	95,916		35		(56)		95,895
Securities of government-sponsored entities	1 to 2	2,500		—		(3)		2,497
Total maturity 1 to 2 years		98,416		35		(59)		98,392
Total available-for-sale securities		$	400,866	$	108	$	(117)	$	400,857

The following is a summary of short-term debt securities classified as available-for-sale as of December 31, 2020 (in thousands):


	Remaining Contractual Maturity (in years)	Amortized Cost		Unrealized Gains		Unrealized Losses		Aggregate Estimated Fair Value
Commercial paper	Less than 1	$	135,161	$	1	$	(17)	$	135,145
Corporate debt securities	Less than 1	92,906		723		—		93,629
Securities of government-sponsored entities	Less than 1	43,031		—		(5)		43,026
Total maturity less than 1 year		271,098		724		(22)		271,800
Corporate debt securities	1 to 2	5,013		4		—		5,017


Total available-for-sale securities		$	276,111	$	728	$	(22)	$	276,817

The primary objective of the Company’s investment portfolio is to preserve capital and liquidity while enhancing overall returns. The Company’s investment policy limits interest-bearing security investments to certain types of instruments issued by institutions with primarily investment grade credit ratings and places restrictions on maturities and concentration by asset class and issuer.

The Company reviews the available-for-sale debt securities for declines in fair value below the cost basis each quarter. For any security whose fair value is below its amortized cost basis, the Company first evaluates whether it intends to sell the impaired security, or will otherwise be more likely than not required to sell the security before recovery. If either are true, the amortized cost basis of the security is written down to its fair value at the reporting date. If neither circumstance holds true, the Company assesses whether any portion of the unrealized loss is a result of a credit loss. Any amount deemed to be attributable to credit loss is recognized in the income statement, with the amount of the loss limited to the difference between fair value and amortized cost and recorded as an allowance for credit losses. The portion of the unrealized loss related to factors other than credit losses is recognized in other comprehensive income (loss).

The following is a summary of available-for-sale debt securities in an unrealized loss position with no credit losses reported as of September 30, 2021 (in thousands):


	Less Than 12 Months				12 Months or Greater				Total
Description of Securities	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
Commercial paper	$	62,421	$	22	$	—	$	—	$	62,421	$	22
Corporate debt securities	116,042		81		—		—		116,042		81
Securities of government-sponsored entities	19,377		14		—		—		19,377		14
Total	$	197,840	$	117	$	—	$	—	$	197,840	$	117

The following is a summary of available-for-sale debt securities in an unrealized loss position with no credit losses reported as of December 31, 2020 (in thousands):


	Less Than 12 Months				12 Months or Greater				Total
Description of Securities	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
Commercial paper	$	112,148	$	17	$	—	$	—	$	112,148	$	17
Corporate debt securities	—		—		—		—		—		—
Securities of government-sponsored entities	43,026		5		—		—		43,026		5
Total	$	155,174	$	22	$	—	$	—	$	155,174	$	22

As of September 30, 2021 and December 31, 2020, the Company does not intend to sell these investments and it is not more likely than not that the Company will be required to sell the investments before recovery of their amortized cost basis. The Company does not believe the unrealized losses incurred during the period are due to credit-related factors. Liquidity issues that arose from economic circumstances surrounding the COVID-19 pandemic have continued to ease and the credit ratings of the securities held remain of the highest quality. While certain securities in the portfolio may be downgraded momentarily, the Federal Reserve has allowed institutions to continue to issue debt where there is need, with the government itself purchasing such securities. Moreover, the Company continues to receive payments of interest and principal as they become due, and our expectation is that those payments will continue to be received timely. Uncertainty surrounding the COVID-19 pandemic, as well as other factors unknown to us at this time, may cause actual results to differ and require adjustments to the Company’s estimates and assumptions in the future.

ACQUISITIONS	9 Months Ended
ACQUISITIONS	Sep. 30, 2021
Business Combination and Asset Acquisition [Abstract]
ACQUISITIONS	ACQUISITIONS Acquisition of Orphan Technologies Limited In November 2020, the Company completed the acquisition of Orphan Technologies Limited (“Orphan”), including Orphan’s rare metabolic disorder drug OT-58, renamed pegtibatinase (TVT-058). The Company acquired Orphan by purchasing all of its outstanding shares. In exchange for the shares, the Company made an upfront cash payment at closing of $90.0 million plus closing adjustments, net liabilities assumed, and transaction expenses of $1.2 million, $1.8 million, and $4.2 million, respectively. Under the Agreement, the Company also agreed to make contingent cash payments up to an aggregate of $427.0 million based on the achievement of certain development, regulatory and commercialization events as set forth in the Agreement, as well as additional tiered mid-single digit royalty payments based upon future net sales of any pegtibatinase (TVT-058) products in the US and Europe, subject to certain reductions as set forth in the Agreement, and a contingent payment in the event a pediatric rare disease voucher for any pegtibatinase (TVT-058) product is granted. The Company applied the principles of ASC 805 in determining the proper accounting treatment for the acquisition. Substantially all of the value of the assets acquired was concentrated within pegtibatinase (TVT-058), and as of the acquisition date, the Company did not anticipate any economic benefit to be derived from pegtibatinase (TVT-058) other than the primary indication. Accordingly, the transaction was treated as an asset acquisition with amounts charged to expense for the acquired in-process research and development on the date of acquisition. In accordance with ASC 450, contingent cash payments will be accrued for when it is probable that a liability has been incurred and the amount can be reasonably estimated. As of September 30, 2021, no contingent cash payments have been accrued.

LEASES

9 Months Ended

Sep. 30, 2021

Leases [Abstract]

LEASES

As of September 30, 2021, the Company had one operating lease with Kilroy Realty, L.P. (the "Landlord") for office space located in San Diego, California, which was entered into in April 2019 and subsequently amended in May 2020. Coinciding with our ability to direct the use of the office space, which occurred in phases over 2020, and utilizing a discount rate equal to our borrowing rate, the Company established ROU assets totaling $34.6 million and lease liabilities totaling $34.5 million. The total ROU asset and lease liability at measurement were each offset by lease incentives associated with tenant improvement allowances totaling $7.9 million.

The initial term of the office lease ends in August 2028, and the Landlord has granted the Company an option to extend the term of the lease by a period of 5 years. At this time, it is not reasonably certain that we will extend the term of the lease and therefore the renewal period has been excluded from the aforementioned ROU asset and lease liability measurements. The measurement of the lease term occurs from the February 2021 occupancy date of the office space delivered in September 2020. The aggregate base rent due over the initial term of the lease is approximately $49.5 million.

Following is a schedule of the future minimum rental commitments for our operating leases reconciled to the lease liability and ROU asset as of September 30, 2021 (in thousands):


	September 30, 2021
2021	$	1,469
2022	6,020
2023	6,200
2024	6,386
2025	6,578
Thereafter	18,535
Total undiscounted future minimum payments	45,188

Present value discount	(8,884)
Total lease liability	36,304
Unamortized lease incentives	(6,805)
Cash payments in excess of straight-line lease expense	(5,692)
Total ROU asset	$	23,807

As of September 30, 2021, the ROU asset of $23.8 million was recorded to the Condensed Consolidated Balance Sheets as non-current Other Assets.

As of September 30, 2021, the current and non-current portions of the lease liability were recorded to the Condensed Consolidated Balance Sheets as follows (in thousands):


	September 30, 2021
Other current liabilities	$	3,803
Other non-current liabilities	32,501
Total lease liabilities	$	36,304

For the three and nine months ended September 30, 2021, the Company recorded $1.2 million and $3.6 million in expense related to operating leases, including amortized tenant improvement allowances. For the three and nine months ended September 30, 2020, the Company recorded $0.7 million and $0.7 million in expense related to operating leases, including amortized tenant improvement allowances.

FAIR VALUE MEASUREMENTS

9 Months Ended

Sep. 30, 2021

Fair Value Disclosures [Abstract]

FAIR VALUE MEASUREMENTS

Financial Instruments and Fair Value

The Company accounts for financial instruments in accordance with ASC 820, Fair Value Measurements and Disclosures (“ASC 820”). ASC 820 establishes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). The three levels of the fair value hierarchy under ASC 820 are described below:

Level 1 – Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities;

Level 2 – Quoted prices in markets that are not active or financial instruments for which all significant inputs are observable, either directly or indirectly; and

Level 3 – Prices or valuations that require inputs that are both significant to the fair value measurement and unobservable.

The valuation techniques used to measure the fair value of the Company’s debt securities and all other financial instruments, all of which have counter-parties with high credit ratings, were valued based on quoted market prices or model driven valuations using significant inputs derived from or corroborated by observable market data. Based on the fair value hierarchy, the Company classified debt securities within Level 2.

The Company acquired two businesses, related to the Cholbam and Chenodal products, whose purchase price included potential future payments that are contingent on the achievement of certain milestones and percentages of future net sales derived from the products acquired. The Company recorded contingent consideration liabilities at their fair value on the acquisition date and revalues them at the end of each reporting period. In estimating the fair value of the Company’s contingent consideration, the Company uses a Monte Carlo Simulation. The determination of the contingent consideration liabilities requires significant judgements including the appropriateness of the valuation model and reasonableness of estimates and assumptions included in the forecasts of future net sales and the discount rates applied to such forecasts. Changes in these estimates and assumptions could have a significant impact on the fair value of the contingent consideration liabilities.

Discount rates used to determine the fair value at September 30, 2021 and December 31, 2020 are as follows:


	Revenue Discount		Payment Discount
	Cholbam	Chenodal
September 30, 2021	6.0%	7.0%	5.80%
December 31, 2020	6.5%	8.5%	7.45%

Based on the fair value hierarchy, the Company classified the fair value measurement of contingent consideration within Level 3 because valuation inputs are based on projected revenues discounted to a present value.

Financial instruments with carrying values approximating fair value include cash and cash equivalents, accounts receivable, and accounts payable, due to their short-term nature. As of September 30, 2021, the fair value of the Company's 2.5% Convertible Senior Notes due 2025 was $280.1 million, which was estimated utilizing market quotations, and are considered Level 2.

The following table presents the Company’s assets and liabilities, measured and recognized at fair value on a recurring basis, classified under the appropriate level of the fair value hierarchy as of September 30, 2021 (in thousands):


	As of September 30, 2021
	Total carrying and estimated fair value		Quoted prices in active markets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)
Assets:
Cash and Cash Equivalents	$	150,327	$	150,327	$	—	$	—
Debt securities, available-for-sale	400,857		—		400,857		—
Total	$	551,184	$	150,327	$	400,857	$	—
Liabilities:
Business combination-related contingent consideration	$	81,400	$	—	$	—	$	81,400
Total	$	81,400	$	—	$	—	$	81,400


	As of December 31, 2020
	Total carrying and estimated fair value		Quoted prices in active markets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)
Assets:
Cash and Cash Equivalents	$	84,772	$	84,772	$	—	$	—
Debt securities, available-for-sale	276,817		—		276,817		—
Total	$	361,589	$	84,772	$	276,817	$	—
Liabilities:
Business combination-related contingent consideration	65,100		—		—		65,100
Total	$	65,100	$	—	$	—	$	65,100

The following table sets forth a summary of changes in the estimated fair value of the Company's Level 3 business combination-related contingent consideration for the nine months ended September 30, 2021 (in thousands):


	Fair Value Measurements of Acquisition-Related Contingent Consideration (Level 3)
Balance at January 1, 2021	$	65,100
Changes in the fair value of contingent consideration	23,960
Contractual payments	(4,883)
Contractual payments included in accrued liabilities at September 30, 2021	(2,662)
Foreign currency impact	(115)
Balance at September 30, 2021	$	81,400

For the three and nine months ended September 30, 2021, the Company incurred charges of $13.9 million and $24.0 million in operating expenses on the Condensed Consolidated Statements of Operations and Comprehensive Loss for the change in fair value of the contingent consideration liabilities. The value changed due to the timing of future payments and changes in market driven discount rates.

For the three and nine months ended September 30, 2020, the Company incurred charges of $5.1 million and $7.4 million in operating expenses on the Condensed Consolidated Statements of Operations and Comprehensive Loss for the change in fair value of the contingent consideration liabilities. The value changed due to the timing of future payments and changes in market driven discount rates.

- 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

INTANGIBLE ASSETS

9 Months Ended

Sep. 30, 2021

Goodwill and Intangible Assets Disclosure [Abstract]

INTANGIBLE ASSETS

As of September 30, 2021, the net book value of amortizable intangible assets was approximately $148.7 million.

The following table sets forth amortizable intangible assets as of September 30, 2021 and December 31, 2020 (in thousands):


	September 30, 2021		December 31, 2020
Finite-lived intangible assets	$	278,395	$	264,676
Less: accumulated amortization	(129,719)		(111,487)
Net carrying value	$	148,676	$	153,189

The following table summarizes amortization expense for the three and nine months ended September 30, 2021 and 2020 (in thousands):


	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Research and development	$	292	$	292	$	866	$	870
Selling, general and administrative	6,052		5,731		17,566		15,612
Total amortization expense	$	6,344	$	6,023	$	18,432	$	16,482

CONVERTIBLE NOTES PAYABLE

9 Months Ended

Sep. 30, 2021

Debt Disclosure [Abstract]

CONVERTIBLE NOTES PAYABLE

Convertible Senior Notes Due 2025

On September 10, 2018, the Company completed its registered underwritten public offering of $276.0 million aggregate principal amount of 2.50% Convertible Senior Notes due 2025 ("2025 Notes"), and entered into a base indenture and supplemental indenture agreement ("2025 Indenture") with respect to the 2025 Notes. The 2025 Notes will mature on September 15, 2025 ("Maturity Date”), unless earlier repurchased, redeemed, or converted. The 2025 Notes are senior unsecured obligations of the Company and bear interest at an annual rate of 2.50%, payable semi-annually in arrears on March 15 and September 15 of each year, beginning on March 15, 2019.

The composition of the Company’s 2025 Notes are as follows (in thousands):


	September 30, 2021		December 31, 2020
2.50% convertible senior notes due 2025	$	276,000	$	276,000
Unamortized debt discount	(48,704)		(56,384)
Unamortized debt issuance costs	(3,600)		(4,277)
Total 2025 Notes, net of unamortized debt discount and debt issuance costs	$	223,696	$	215,339

The net proceeds from the issuance of the 2025 Notes were approximately $267.2 million, after deducting commissions and the offering expenses payable by the Company. A portion of the net proceeds from the 2025 Notes was used by the Company to repurchase $23.4 million aggregate principal amount of its then-outstanding 4.5% senior convertible notes due 2019 in privately-negotiated transactions.

Holders may convert their 2025 Notes at their option only in the following circumstances: (1) during any calendar quarter commencing after the calendar quarter ending on December 31, 2018 (and only during such calendar quarter), if the last reported sale price per share of the Company’s common stock for each of at least 20 trading days, whether or not consecutive, during the period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter exceeds 130% of the conversion price on the applicable trading day; (2) during the five consecutive business days immediately after any 10 consecutive trading day period (“measurement period”) if the trading price per $1,000 principal amount of 2025 Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price per share of the Company’s common stock on such trading day and the conversion rate on such trading day; (3) upon the occurrence of certain corporate events or distributions on the Company’s common stock; (4) if the Company calls the 2025 Notes for redemption; and (5) at any time from, and including, May 15, 2025 until the close of business on the scheduled trading day immediately before the Maturity Date. The Company will settle conversions by paying or delivering, as applicable, cash, shares of the Company’s common stock, or a combination of cash and shares of the Company’s common stock, at the Company’s election, based on the applicable conversion rate.

The initial conversion rate for the 2025 Notes is 25.7739 shares of the Company’s common stock per $1,000 principal amount of 2025 Notes, which represents an initial conversion price of approximately $38.80 per share. If a “make-whole fundamental change” (as defined in the 2025 Indenture) occurs, then the Company will, in certain circumstances, increase the conversion rate for a specified period of time.

The 2025 Notes will be redeemable, in whole or in part, at the Company’s option at any time, and from time to time, on or after September 15, 2022 and, in the case of any partial redemption, on or before the 40th scheduled trading day before the Maturity Date, at a cash redemption price equal to the principal amount of the 2025 Notes to be redeemed, plus accrued and unpaid interest, if any, to, but excluding, the redemption date, but only if the last reported sale price per share of the Company’s common stock exceeds 130% of the conversion price on each of at least 20 trading days during the 30 consecutive trading days ending on, and including, the trading day immediately before the date the Company sends the related redemption notice. If a fundamental change (as defined in the 2025 Indenture) occurs, then, subject to certain exceptions, holders may require the Company to repurchase their 2025 Notes at a cash repurchase price equal to the principal amount of the 2025 Notes to be repurchased, plus accrued and unpaid interest, if any, to, but excluding, the fundamental change repurchase date.

As of September 30, 2021, the 2025 Notes had a market price of $1,015 per $1,000 principal amount or $280.1 million. In the event of conversion, holders would forgo all future interest payments, any unpaid accrued interest and the possibility of further stock price appreciation. Upon the receipt of conversion requests, the settlement of the 2025 Notes will be paid pursuant to the terms of the 2025 Indenture. In the event that all of the 2025 Notes are converted, the Company would be required to repay the $276.0 million principal amount and any conversion premium in any combination of cash and shares of its common stock at the Company’s option. In addition, calling the 2025 Notes for redemption will constitute a “make-whole fundamental change."

The 2025 Notes are the Company’s general unsecured obligations that rank senior in right of payment to all of its indebtedness that is expressly subordinated in right of payment to the 2025 Notes, and equal in right of payment to the Company’s unsecured indebtedness.

The 2025 Notes are classified on the Company’s Condensed Consolidated Balance Sheets at September 30, 2021 as long-term convertible debt.

Under ASC 470-20, Debt with Conversion and Other Options, an entity must separately account for the liability and equity components of convertible debt instruments (such as the 2025 Notes) that may be settled entirely or partially in cash upon conversion, in a manner that reflects the issuer’s economic interest cost. The liability component of the instrument is valued in a manner that reflects the market interest rate for a similar nonconvertible instrument at the date of issuance. The initial carrying value of the liability component was $198.6 million. The equity component of $77.4 million, representing the conversion option, was determined by deducting the fair value of the liability component from the par value of the 2025 Notes and was recorded in additional paid-in capital on the consolidated balance sheet at the issuance date. That equity component is treated as a discount on the liability component of the 2025 Notes, which is amortized over the seven-year term of the 2025 Notes using the effective interest rate method. The equity component is not re-measured as long as it continues to meet the conditions for equity classification. The Company allocated the total transaction costs of approximately $8.8 million related to the issuance of the 2025 Notes to the liability and equity components of the 2025 Notes based on their relative values. Transaction costs attributable to the liability component are amortized to interest expense over the seven-year term of the 2025 Notes, and transaction costs attributable to the equity component are netted with the equity component in stockholders’ equity.

The effective interest rate on the liability components of the 2025 Notes for the period from the date of issuance through September 30, 2021 was 7.7%. The following table sets forth total interest expense recognized related to the 2025 Notes (in thousands):


	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Contractual interest expense	$	1,725	$	1,725	$	5,175	$	5,175
Amortization of debt discount	2,609		2,417		7,680		7,115
Amortization of debt issuance costs	226		225		677		674
Total interest expense for the 2025 Notes	$	4,560	$	4,367	$	13,532	$	12,964

The 2025 Notes do not contain any financial or operating covenants or any restrictions on the payment of dividends, the issuance of other indebtedness or the issuance or repurchase of securities by the Company. The 2025 Indenture contains customary events of default with respect to the 2025 Notes, including that upon certain events of default, 100% of the principal and accrued and unpaid interest on the 2025 Notes will automatically become due and payable.

- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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+ Details

ACCRUED EXPENSES

9 Months Ended

Sep. 30, 2021

Payables and Accruals [Abstract]

ACCRUED EXPENSES

Accrued expenses at September 30, 2021 and December 31, 2020 consisted of the following (in thousands):


	September 30, 2021		December 31, 2020
Government rebates payable	$	11,311	$	10,707
Compensation related costs	16,896		17,912
Accrued royalties and contingent consideration	8,360		7,857
Research and development	22,163		10,166
Selling, general and administrative	3,117		3,944

Miscellaneous accrued expenses	1,461		6,207
Total accrued expenses	$	63,308	$	56,793

NET LOSS PER COMMON SHARE

9 Months Ended

Sep. 30, 2021

Earnings Per Share [Abstract]

NET LOSS PER COMMON SHARE

Basic and diluted net loss per common share is calculated by dividing net loss applicable to common stockholders by the weighted-average number of common shares outstanding during the period. The Company’s potentially dilutive shares, which include outstanding stock options, restricted stock units, and shares issuable upon conversion of the 2025 Notes, are considered to be common stock equivalents and are not included in the calculation of diluted net loss per share because their effect is anti-dilutive.

Basic and diluted net loss per share is calculated as follows (net loss amounts are stated in thousands):


	Three Months Ended September 30,
	2021					2020
	Shares	Net Loss		Loss per common share		Shares	Net Loss		Loss per common share
Basic and diluted loss per share	60,803,045	$	(35,639)	$	(0.59)	50,929,575	$	(22,549)	$	(0.44)







	Nine Months Ended September 30,
	2021					2020
	Shares	Net Loss		Loss per common share		Shares	Net Loss		Loss per common share
Basic and diluted loss per share	59,230,881	$	(128,518)	$	(2.17)	46,289,103	$	(47,809)	$	(1.03)

The following common stock equivalents have been excluded because they were anti-dilutive:


	Three Months Ended September 30,		Nine Months Ended September 30,
	2021	2020	2021	2020
Restricted stock	1,538,792	1,400,555	1,588,737	1,384,748
Convertible debt	7,113,402	7,113,402	7,113,402	7,113,402
Options	9,332,608	8,397,889	9,309,981	8,351,302

Total anti-dilutive shares	17,984,802	16,911,846	18,012,120	16,849,452

COMMITMENTS AND CONTINGENCIES	9 Months Ended
COMMITMENTS AND CONTINGENCIES	Sep. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Research Collaboration and Licensing Agreements As part of the Company's research and development efforts, the Company enters into research collaboration and licensing agreements with unrelated companies, scientific collaborators, universities, and consultants. These agreements contain varying terms and provisions which include fees and milestones to be paid by the Company, services to be provided, and ownership rights to certain proprietary technology developed under the agreements. Some of these agreements contain provisions which require the Company to pay royalties, in the event the Company sells or licenses any proprietary products developed under the respective agreements. Legal Proceedings From time to time in the normal course of business, the Company is subject to various legal matters such as threatened or pending claims or litigation. Although the results of claims and litigation cannot be predicted with certainty, the Company does not believe it is a party to any claim or litigation the outcome of which, if determined adversely to it, would individually or in the aggregate be reasonably expected to have a material adverse effect on its results of operations or financial condition.

SHARE-BASED COMPENSATION

9 Months Ended

Sep. 30, 2021

Equity [Abstract]

SHARE-BASED COMPENSATION

Restricted Stock Units

Service Based Restricted Stock Units

The following table summarizes the Company’s service based restricted stock unit activity during the nine months ended September 30, 2021:


	Number of Restricted Stock Units	Weighted Average Grant Date Fair Value
Unvested December 31, 2020	1,109,942	$	17.84
Granted	859,373	24.87
Vested	(383,211)	18.09
Forfeited/canceled	(132,147)	21.57
Unvested September 30, 2021	1,453,957	$	21.59

At September 30, 2021, unamortized stock compensation for service based restricted stock units was $25.2 million, with a weighted-average recognition period of 2.6 years.

Performance Based Restricted Stock Units

The following table summarizes the Company’s performance based restricted stock unit activity during the nine months ended September 30, 2021:


	Number of Restricted Stock Units	Weighted Average Grant Date Fair Value
Unvested December 31, 2020	167,500	$	16.48
Granted	—	—
Vested	(115,000)	15.46
Forfeited/canceled	—	—
Unvested September 30, 2021	52,500	$	18.73

At September 30, 2021, unamortized stock compensation for performance based restricted stock units was less than $0.1 million, with a weighted-average recognition period of 0.8 years.

Stock Options

The following table summarizes stock option activity during the nine months ended September 30, 2021:


	Shares Underlying Options	Weighted Average Exercise Price	Weighted Average Remaining Contractual Life (years)	Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2020	8,242,996	$18.97	6.43	$	71,641
Granted	1,723,807	25.23
Exercised	(456,014)	14.65
Forfeited/canceled	(387,875)	23.87
Outstanding at September 30, 2021	9,122,914	$20.17	6.36	$	47,013

At September 30, 2021, unamortized stock compensation for stock options was $34.0 million, with a weighted-average recognition period of 2.6 years.

At September 30, 2021, outstanding options to purchase 6.1 million shares of common stock were exercisable with a weighted-average exercise price per share of $19.33.

Share-Based Compensation

The following table sets forth total share-based compensation for the three and nine months ended September 30, 2021 and 2020 (in thousands):


	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Research and development	$	2,630	$	2,510	$	8,477	$	6,968
Selling, general & administrative	4,356		2,888		13,713		10,294
Total	$	6,986	$	5,398	$	22,190	$	17,262

INCOME TAXES	9 Months Ended
INCOME TAXES	Sep. 30, 2021
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXESFor the nine months ended September 30, 2021, we recognized an income tax expense of $0.4 million as compared to an income tax benefit of $18.9 million for the nine months ended September 30, 2020. The change is primarily related to provisions of the Coronavirus Aid, Relief, and Economic Security Act ("CARES Act") concerning net operating loss carrybacks which were effected in 2020.

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

INVENTORY

9 Months Ended

Sep. 30, 2021

Inventory Disclosure [Abstract]

INVENTORY

Inventory, net of reserves, consisted of the following at September 30, 2021 and December 31, 2020 (in thousands):


	September 30, 2021		December 31, 2020
Raw materials	$	3,819	$	3,219
Finished goods	2,797		4,389
Total inventory	$	6,616	$	7,608

The inventory reserve was $3.6 million at both September 30, 2021 and December 31, 2020.

ACCOUNTS RECEIVABLE	9 Months Ended
ACCOUNTS RECEIVABLE	Sep. 30, 2021
Receivables [Abstract]
ACCOUNTS RECEIVABLE	ACCOUNTS RECEIVABLEAccounts receivable, net of reserves for prompt pay discounts and expected credit losses, was $13.4 million and $15.9 million at September 30, 2021 and December 31, 2020, respectively. The total reserves for both periods were immaterial.The Company's evaluation and application of ASU No. 2016-13, Financial Instruments - Credit Losses for the current period included an assessment of our aged trade receivables balances and their underlying credit risk characteristics. Our evaluation of past events, current conditions, and reasonable and supportable forecasts about the future resulted in an expectation of immaterial credit losses.

EQUITY OFFERINGS	9 Months Ended
EQUITY OFFERINGS	Sep. 30, 2021
Equity [Abstract]
EQUITY OFFERINGS	EQUITY OFFERINGS Underwritten Public Offering of Common Stock In June 2020, the Company sold an aggregate of 7.5 million shares of its common stock in an underwritten public offering, at a price of $15.50 per share. The net proceeds to the Company from the offering, after deducting the underwriting discounts and offering expenses, were $108.7 million. In February 2021, the Company sold an aggregate of 7.5 million shares of its common stock in an underwritten public offering, at a price of $26.75 per share. The net proceeds to the Company from the offering, after deducting the underwriting discounts and offering expenses, were $189.3 million. At-the-Market Equity Offering In February 2020, the Company entered into an Open Market Sale Agreement ("ATM Agreement") with Jefferies LLC, as agent (“Jefferies”), pursuant to which the Company may offer and sell, from time to time through Jefferies, shares of its common stock having an aggregate offering price of up to $100.0 million. Of the $100.0 million originally authorized for sale under the ATM Agreement, approximately $28.6 million were sold under the Company’s prior registration statement on Form S-3 (Registration No. 333-227182), and the remaining approximately $71.4 million will be sold, if at all, under the Company's effective registration statement on Form S-3 (Registration Statement No. 333-259311). Through September 30, 2021, the Company has sold a total of 1,051,992 shares under the ATM Agreement, resulting in gross proceeds of $28.6 million. $4.9 million of this total relates to the settlement of 184,186 shares in the first quarter of 2021. As of September 30, 2021, an aggregate of $71.4 million remained eligible for sale under the ATM Agreement. Authorized Shares of Common Stock On May 14, 2021, in connection with the Company’s 2021 Annual Meeting of Stockholders, the Company’s stockholders approved, among other matters, a Certificate of Amendment (“Certificate of Amendment”) to the Company’s Certificate of Incorporation to increase the number of shares of common stock authorized for issuance thereunder from 100,000,000 to 200,000,000. Effective May 18, 2021, the Certificate of Amendment was filed with the Secretary of State of the State of Delaware.

BASIS OF PRESENTATION AND SIGNIFICANT ACCCOUNTING POLICIES (Policies)	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation The unaudited condensed consolidated financial statements represent the consolidation of the accounts of the Company and its subsidiaries in conformity with GAAP. All intercompany accounts and transactions have been eliminated in consolidation.
Revenue Recognition	Revenue RecognitionThe Company recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. To determine revenue recognition for arrangements that an entity determines are within the scope of Accounting Standards Codification ("ASC") 606, Revenue from Contracts with Customers ("ASC 606"), the entity performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the entity satisfies a performance obligation. The Company only applies the five-step model to contracts when it is probable that the entity will collect substantially all the consideration it is entitled to in exchange for the goods or services it transfers to the customer. Deductions from Revenue Revenues from product sales are recorded at the net sales price, which includes provisions resulting from discounts, rebates and co-pay assistance that are offered to customers, health care providers, payors and other indirect customers relating to the Company’s sales of its products. These provisions are based on the amounts earned or to be claimed on the related sales and are classified as a reduction of accounts receivable (if the amount is payable to a customer) or as a current liability (if the amount is payable to a party other than a customer). Where appropriate, these reserves take into consideration the Company’s historical experience, current contractual and statutory requirements and specific known market events and trends. Overall, these reserves reflect the Company’s best estimates of the amount of consideration to which it is entitled based on the terms of the contract. If actual results in the future vary from the Company’s provisions, the Company will adjust the provision, which would affect net product revenue and earnings in the period such variances become known. Our historical experience is that such adjustments have been immaterial. Government Rebates: We calculate the rebates that we will be obligated to provide to government programs and deduct these estimated amounts from our gross product sales at the time the revenues are recognized. Allowances for government rebates and discounts are established based on actual payer information, which is reasonably estimated at the time of delivery, and the government-mandated discounts applicable to government-funded programs. Rebate discounts are included in other current liabilities in the accompanying consolidated balance sheets. Commercial Rebates: We calculate the rebates that we incur due to contracts with certain commercial payors and deduct these amounts from our gross product sales at the time the revenues are recognized. Allowances for commercial rebates are established based on actual payer information, which is reasonably estimated at the time of delivery. Rebate discounts are included in other current liabilities in the accompanying consolidated balance sheets. Prompt Pay Discounts: We offer discounts to certain customers for prompt payments. We accrue for the calculated prompt pay discount based on the gross amount of each invoice for those customers at the time of sale. Product Returns: Consistent with industry practice, we offer our customers a limited right to return product purchased directly from the Company, which is principally based upon the product’s expiration date. Generally, shipments are only made upon a patient prescription thus returns are minimal. Co-pay Assistance: We offer a co-pay assistance program, which is intended to provide financial assistance to qualified commercially insured patients with prescription drug co-payments required by payors. The calculation of the accrual for co-pay assistance is based on an identification of claims and the cost per claim associated with product that has been recognized as revenue.
Collaborative Arrangements	Payments received under collaboration and licensing agreements may include non-refundable fees at the inception of the arrangements, milestone payments for specific achievements and royalties on the sale of products. At the inception of arrangements that include milestone payments, the Company uses judgement to evaluate whether the milestones are probable of being achieved and estimates the amount to include in the transaction price utilizing the most likely amount method. If it is probable that a significant revenue reversal will not occur, the estimated amount is included in the transaction price. Milestone payments that are not within the Company or the licensee’s control, such as regulatory approvals are not included in the transaction price until those approvals are received. At the end of each reporting period, the Company re-evaluates the probability of achievement of development milestones and any related constraint and adjusts the estimate of the overall transaction price, if necessary. The Company recognizes aggregate sales-based milestones and royalty payments from product sales at the later of when the related sales occur or when the performance obligation to which the sales-based milestone or royalty has been allocated has been satisfied. If it is probable that a significant revenue reversal will not occur, the Company estimates the sales-based milestone and royalty payments using the most likely amount method. The Company utilizes significant judgement to develop estimates of the stand-alone selling price for each distinct performance obligation based upon the relative stand-alone selling price. Variable consideration that relates specifically to the Company’s efforts to satisfy specific performance obligations is allocated entirely to those performance obligations. The stand-alone selling price for license-related performance obligations requires judgement in developing assumptions to project probability-weighted cash flows based upon estimates of forecasted revenues, clinical and regulatory timelines and discount rates. The stand-alone selling price for clinical development performance obligations is based on forecasted expected costs of satisfying a performance obligation plus an appropriate margin. If the licenses to intellectual property are determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenues from non-refundable, upfront fees allocated to the license when the license is transferred to the licensee and the licensee is able to benefit from the license. For licenses that are not distinct from other promises, the Company applies judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue from non-refundable, upfront fees. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the related revenue recognition accordingly. The selection of the method to measure progress towards completion requires judgment and is based on the nature of the products or services to be provided. Revenue is recorded proportionally as costs are incurred. The Company generally utilizes the cost-to-cost method of progress because it best measures the transfer of control to the customer which occurs as the Company incurs costs. Under the cost-to-cost measure of progress, the extent of progress towards completion is measured based on the ratio of costs incurred to date to the total estimated costs at completion of the performance obligation. The Company uses judgment to estimate the total costs expected to complete the clinical development performance obligations, which include subcontractor costs, labor, materials, other direct costs and an allocation of indirect costs. The Company evaluates these cost estimates and the progress each reporting period and adjusts the measure of progress, if necessary.
Research and Development Expense	Research and Development Expenses Research and development expenses are comprised of salaries and bonuses, benefits, non-cash share-based compensation, license fees, costs paid to third-party contractors to perform research, conduct clinical trials and pre/non-clinical trials, develop drug materials, and associated overhead expenses and facilities. We also incur indirect costs that are not allocated to specific programs because such costs benefit multiple development programs and allow us to increase our pharmaceutical development capabilities. These consist of internal shared resources related to the development and maintenance of systems and processes applicable to all of our programs.
Clinical Trial Expenses	Clinical Trial Expenses Our clinical trials are conducted pursuant to contracts with contract research organizations ("CROs") that support conducting and managing clinical trials. The financial terms and activities of these agreements vary from contract to contract and may result in uneven expense levels. Generally, these agreements set forth activities that drive the recording of expenses such as start-up, initiation activities, enrollment, treatment of patients, or the completion of other clinical trial activities. Expenses related to clinical trials are accrued based on our estimates and/or representations from service providers regarding work performed, including actual level of patient enrollment, completion of patient studies and progress of the clinical trials. Other incidental costs related to patient enrollment or treatment are accrued when reasonably certain. If the amounts we are obligated to pay under our clinical trial agreements are modified (for instance, as a result of changes in the clinical trial protocol or scope of work to be performed), we adjust our accruals accordingly on a prospective basis. Revisions to our contractual payment obligations are charged to expense in the period in which the facts that give rise to the revision become reasonably certain. We currently have three Phase 3 clinical trials in process that are in varying stages of activity, with ongoing non-clinical support trials. As such, clinical trial expenses will vary depending on all the factors set forth above and may fluctuate significantly from quarter to quarter.
Intangible Assets with Cost Accumulation Model	Intangible Assets with Cost Accumulation Model In 2014, the Company entered into a license agreement with Mission Pharmacal in which the Company obtained the exclusive right to license the trademark of Thiola. The acquisition of the Thiola license qualified as an asset acquisition under the principles of ASC 805 in effect at the time of acquisition. The license agreement requires the Company to make royalty payments based on net sales of Thiola. The liability for royalties in excess of the annual contractual minimum is recognized in the period in which the royalties become probable and estimable, which is typically in the period corresponding with the respective sales. The Company records an offsetting increase to the cost basis of the asset under the cost accumulation model. The additional cost basis is subsequently amortized over the remaining life of the license agreement. Consistent with all prior periods since Thiola was acquired, the Company has not accrued any liability for royalties in excess of the annual contractual minimum at September 30, 2021, as such royalties are not yet probable and estimable.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board ("FASB") or other standard setting bodies. Unless otherwise discussed, the Company believes that the impact of recently issued standards that are not yet effective will not have a material impact on its consolidated financial position or results of operations upon adoption. In August 2020, the FASB issued ASU No. 2020-06, Accounting for Convertible Instruments and Contracts in an Entity's Own Equity. The ASU includes amendments to the guidance on convertible instruments and the derivative scope exception for contracts in an entity's own equity and simplifies the accounting for convertible instruments which include beneficial conversion features or cash conversion features by removing certain separation models in Subtopic 470-20. Additionally, the ASU will require entities to use the "if-converted" method when calculating diluted earnings per share for convertible instruments. The ASU is effective for fiscal years beginning after December 15, 2021, including interim periods within those fiscal years. The Company's assessment of the impact of the new standard on the Company's financial statements is ongoing.
Marketable Securities	The primary objective of the Company’s investment portfolio is to preserve capital and liquidity while enhancing overall returns. The Company’s investment policy limits interest-bearing security investments to certain types of instruments issued by institutions with primarily investment grade credit ratings and places restrictions on maturities and concentration by asset class and issuer.
Fair Value Measurement	Financial Instruments and Fair Value The Company accounts for financial instruments in accordance with ASC 820, Fair Value Measurements and Disclosures (“ASC 820”). ASC 820 establishes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). The three levels of the fair value hierarchy under ASC 820 are described below: Level 1 – Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities; Level 2 – Quoted prices in markets that are not active or financial instruments for which all significant inputs are observable, either directly or indirectly; and Level 3 – Prices or valuations that require inputs that are both significant to the fair value measurement and unobservable. The valuation techniques used to measure the fair value of the Company’s debt securities and all other financial instruments, all of which have counter-parties with high credit ratings, were valued based on quoted market prices or model driven valuations using significant inputs derived from or corroborated by observable market data. Based on the fair value hierarchy, the Company classified debt securities within Level 2.The Company acquired two businesses, related to the Cholbam and Chenodal products, whose purchase price included potential future payments that are contingent on the achievement of certain milestones and percentages of future net sales derived from the products acquired. The Company recorded contingent consideration liabilities at their fair value on the acquisition date and revalues them at the end of each reporting period. In estimating the fair value of the Company’s contingent consideration, the Company uses a Monte Carlo Simulation. The determination of the contingent consideration liabilities requires significant judgements including the appropriateness of the valuation model and reasonableness of estimates and assumptions included in the forecasts of future net sales and the discount rates applied to such forecasts. Changes in these estimates and assumptions could have a significant impact on the fair value of the contingent consideration liabilities.
Income (Loss) Per Share	Basic and diluted net loss per common share is calculated by dividing net loss applicable to common stockholders by the weighted-average number of common shares outstanding during the period. The Company’s potentially dilutive shares, which include outstanding stock options, restricted stock units, and shares issuable upon conversion of the 2025 Notes, are considered to be common stock equivalents and are not included in the calculation of diluted net loss per share because their effect is anti-dilutive.

REVENUE RECOGNITION (Tables)

9 Months Ended

Sep. 30, 2021

Revenue from Contract with Customer [Abstract]

Summary of net product revenue

The following table summarizes net product sales for the three and nine months ended September 30, 2021 and 2020 (in thousands):


	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Bile acid products	$	24,353	$	22,912	$	71,291	$	66,766
Tiopronin products	29,821		28,227		84,907		80,572
Total net product sales	$	54,174	$	51,139	$	156,198	$	147,338

DEBT SECURITIES (Tables)

9 Months Ended

Sep. 30, 2021

Investments, Debt and Equity Securities [Abstract]

Schedule of marketable securities

Debt securities consisted of the following (in thousands):


	September 30, 2021		December 31, 2020
Commercial paper	$	148,874	$	135,145
Corporate debt securities	227,530		98,646
Securities of government sponsored entities	24,453		43,026
Total debt securities	$	400,857	$	276,817

Debt securities available for sale

The following is a summary of short-term debt securities classified as available-for-sale as of September 30, 2021 (in thousands):


	Remaining Contractual Maturity (in years)	Amortized Cost		Unrealized Gains		Unrealized Losses		Aggregate Estimated Fair Value
Commercial paper	Less than 1	$	148,886	$	10	$	(22)	$	148,874
Corporate debt securities	Less than 1	131,598		62		(25)		131,635
Securities of government-sponsored entities	Less than 1	21,966		1		(11)		21,956
Total maturity less than 1 year		302,450		73		(58)		302,465
Corporate debt securities	1 to 2	95,916		35		(56)		95,895
Securities of government-sponsored entities	1 to 2	2,500		—		(3)		2,497
Total maturity 1 to 2 years		98,416		35		(59)		98,392
Total available-for-sale securities		$	400,866	$	108	$	(117)	$	400,857

The following is a summary of short-term debt securities classified as available-for-sale as of December 31, 2020 (in thousands):


	Remaining Contractual Maturity (in years)	Amortized Cost		Unrealized Gains		Unrealized Losses		Aggregate Estimated Fair Value
Commercial paper	Less than 1	$	135,161	$	1	$	(17)	$	135,145
Corporate debt securities	Less than 1	92,906		723		—		93,629
Securities of government-sponsored entities	Less than 1	43,031		—		(5)		43,026
Total maturity less than 1 year		271,098		724		(22)		271,800
Corporate debt securities	1 to 2	5,013		4		—		5,017


Total available-for-sale securities		$	276,111	$	728	$	(22)	$	276,817

Schedule of securities in an unrealized loss position

The following is a summary of available-for-sale debt securities in an unrealized loss position with no credit losses reported as of September 30, 2021 (in thousands):


	Less Than 12 Months				12 Months or Greater				Total
Description of Securities	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
Commercial paper	$	62,421	$	22	$	—	$	—	$	62,421	$	22
Corporate debt securities	116,042		81		—		—		116,042		81
Securities of government-sponsored entities	19,377		14		—		—		19,377		14
Total	$	197,840	$	117	$	—	$	—	$	197,840	$	117

The following is a summary of available-for-sale debt securities in an unrealized loss position with no credit losses reported as of December 31, 2020 (in thousands):


	Less Than 12 Months				12 Months or Greater				Total
Description of Securities	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
Commercial paper	$	112,148	$	17	$	—	$	—	$	112,148	$	17
Corporate debt securities	—		—		—		—		—		—
Securities of government-sponsored entities	43,026		5		—		—		43,026		5
Total	$	155,174	$	22	$	—	$	—	$	155,174	$	22

LEASES (Tables)

9 Months Ended

Sep. 30, 2021

Leases [Abstract]

Schedule of future minimum rent commitments

Following is a schedule of the future minimum rental commitments for our operating leases reconciled to the lease liability and ROU asset as of September 30, 2021 (in thousands):


	September 30, 2021
2021	$	1,469
2022	6,020
2023	6,200
2024	6,386
2025	6,578
Thereafter	18,535
Total undiscounted future minimum payments	45,188

Present value discount	(8,884)
Total lease liability	36,304
Unamortized lease incentives	(6,805)
Cash payments in excess of straight-line lease expense	(5,692)
Total ROU asset	$	23,807

Supplemental balance sheet information

As of September 30, 2021, the current and non-current portions of the lease liability were recorded to the Condensed Consolidated Balance Sheets as follows (in thousands):


	September 30, 2021
Other current liabilities	$	3,803
Other non-current liabilities	32,501
Total lease liabilities	$	36,304

FAIR VALUE MEASUREMENTS (Tables)

9 Months Ended

Sep. 30, 2021

Fair Value Disclosures [Abstract]

Schedule of discount rates used in valuation

Discount rates used to determine the fair value at September 30, 2021 and December 31, 2020 are as follows:


	Revenue Discount		Payment Discount
	Cholbam	Chenodal
September 30, 2021	6.0%	7.0%	5.80%
December 31, 2020	6.5%	8.5%	7.45%

Schedule of fair value on a recurring basis


	As of September 30, 2021
	Total carrying and estimated fair value		Quoted prices in active markets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)
Assets:
Cash and Cash Equivalents	$	150,327	$	150,327	$	—	$	—
Debt securities, available-for-sale	400,857		—		400,857		—
Total	$	551,184	$	150,327	$	400,857	$	—
Liabilities:
Business combination-related contingent consideration	$	81,400	$	—	$	—	$	81,400
Total	$	81,400	$	—	$	—	$	81,400


	As of December 31, 2020
	Total carrying and estimated fair value		Quoted prices in active markets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)
Assets:
Cash and Cash Equivalents	$	84,772	$	84,772	$	—	$	—
Debt securities, available-for-sale	276,817		—		276,817		—
Total	$	361,589	$	84,772	$	276,817	$	—
Liabilities:
Business combination-related contingent consideration	65,100		—		—		65,100
Total	$	65,100	$	—	$	—	$	65,100

Schedule of summary of changes in estimated acquisition related contingent consideration


	Fair Value Measurements of Acquisition-Related Contingent Consideration (Level 3)
Balance at January 1, 2021	$	65,100
Changes in the fair value of contingent consideration	23,960
Contractual payments	(4,883)
Contractual payments included in accrued liabilities at September 30, 2021	(2,662)
Foreign currency impact	(115)
Balance at September 30, 2021	$	81,400

INTANGIBLE ASSETS (Tables)

9 Months Ended

Sep. 30, 2021

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of finite-lived amortizable intangible assets

The following table sets forth amortizable intangible assets as of September 30, 2021 and December 31, 2020 (in thousands):


	September 30, 2021		December 31, 2020
Finite-lived intangible assets	$	278,395	$	264,676
Less: accumulated amortization	(129,719)		(111,487)
Net carrying value	$	148,676	$	153,189

Schedule of amortization expense

The following table summarizes amortization expense for the three and nine months ended September 30, 2021 and 2020 (in thousands):


	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Research and development	$	292	$	292	$	866	$	870
Selling, general and administrative	6,052		5,731		17,566		15,612
Total amortization expense	$	6,344	$	6,023	$	18,432	$	16,482

CONVERTIBLE NOTES PAYABLE (Tables)

9 Months Ended

Sep. 30, 2021

Debt Disclosure [Abstract]

Schedule of long-term debt instruments

The composition of the Company’s 2025 Notes are as follows (in thousands):


	September 30, 2021		December 31, 2020
2.50% convertible senior notes due 2025	$	276,000	$	276,000
Unamortized debt discount	(48,704)		(56,384)
Unamortized debt issuance costs	(3,600)		(4,277)
Total 2025 Notes, net of unamortized debt discount and debt issuance costs	$	223,696	$	215,339


	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Contractual interest expense	$	1,725	$	1,725	$	5,175	$	5,175
Amortization of debt discount	2,609		2,417		7,680		7,115
Amortization of debt issuance costs	226		225		677		674
Total interest expense for the 2025 Notes	$	4,560	$	4,367	$	13,532	$	12,964

- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
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+ Details

ACCRUED EXPENSES (Tables)

9 Months Ended

Sep. 30, 2021

Payables and Accruals [Abstract]

Schedule of Accrued Expenses

Accrued expenses at September 30, 2021 and December 31, 2020 consisted of the following (in thousands):


	September 30, 2021		December 31, 2020
Government rebates payable	$	11,311	$	10,707
Compensation related costs	16,896		17,912
Accrued royalties and contingent consideration	8,360		7,857
Research and development	22,163		10,166
Selling, general and administrative	3,117		3,944

Miscellaneous accrued expenses	1,461		6,207
Total accrued expenses	$	63,308	$	56,793

NET LOSS PER COMMON SHARE (Tables)

9 Months Ended

Sep. 30, 2021

Earnings Per Share [Abstract]

Schedule of basic and diluted net loss per share

Basic and diluted net loss per share is calculated as follows (net loss amounts are stated in thousands):


	Three Months Ended September 30,
	2021					2020
	Shares	Net Loss		Loss per common share		Shares	Net Loss		Loss per common share
Basic and diluted loss per share	60,803,045	$	(35,639)	$	(0.59)	50,929,575	$	(22,549)	$	(0.44)







	Nine Months Ended September 30,
	2021					2020
	Shares	Net Loss		Loss per common share		Shares	Net Loss		Loss per common share
Basic and diluted loss per share	59,230,881	$	(128,518)	$	(2.17)	46,289,103	$	(47,809)	$	(1.03)

Schedule of common stock options, convertible debt and restricted stock units anti-dilutive

The following common stock equivalents have been excluded because they were anti-dilutive:


	Three Months Ended September 30,		Nine Months Ended September 30,
	2021	2020	2021	2020
Restricted stock	1,538,792	1,400,555	1,588,737	1,384,748
Convertible debt	7,113,402	7,113,402	7,113,402	7,113,402
Options	9,332,608	8,397,889	9,309,981	8,351,302

Total anti-dilutive shares	17,984,802	16,911,846	18,012,120	16,849,452

SHARE-BASED COMPENSATION (Tables)

9 Months Ended

Sep. 30, 2021

Equity [Abstract]

Schedule of service based restricted stock activity

The following table summarizes the Company’s service based restricted stock unit activity during the nine months ended September 30, 2021:


	Number of Restricted Stock Units	Weighted Average Grant Date Fair Value
Unvested December 31, 2020	1,109,942	$	17.84
Granted	859,373	24.87
Vested	(383,211)	18.09
Forfeited/canceled	(132,147)	21.57
Unvested September 30, 2021	1,453,957	$	21.59

Schedule of performance based restricted stock activity

The following table summarizes the Company’s performance based restricted stock unit activity during the nine months ended September 30, 2021:


	Number of Restricted Stock Units	Weighted Average Grant Date Fair Value
Unvested December 31, 2020	167,500	$	16.48
Granted	—	—
Vested	(115,000)	15.46
Forfeited/canceled	—	—
Unvested September 30, 2021	52,500	$	18.73

Schedule of stock option issuances and balances outstanding

The following table summarizes stock option activity during the nine months ended September 30, 2021:


	Shares Underlying Options	Weighted Average Exercise Price	Weighted Average Remaining Contractual Life (years)	Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2020	8,242,996	$18.97	6.43	$	71,641
Granted	1,723,807	25.23
Exercised	(456,014)	14.65
Forfeited/canceled	(387,875)	23.87
Outstanding at September 30, 2021	9,122,914	$20.17	6.36	$	47,013

Schedule of share based compensation expenses

The following table sets forth total share-based compensation for the three and nine months ended September 30, 2021 and 2020 (in thousands):


	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Research and development	$	2,630	$	2,510	$	8,477	$	6,968
Selling, general & administrative	4,356		2,888		13,713		10,294
Total	$	6,986	$	5,398	$	22,190	$	17,262

INVENTORY (Tables)

9 Months Ended

Sep. 30, 2021

Inventory Disclosure [Abstract]

Schedule of inventory

Inventory, net of reserves, consisted of the following at September 30, 2021 and December 31, 2020 (in thousands):


	September 30, 2021		December 31, 2020
Raw materials	$	3,819	$	3,219
Finished goods	2,797		4,389
Total inventory	$	6,616	$	7,608

REVENUE RECOGNITION (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
REVENUE RECOGNITION (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation of Revenue [Line Items]
Net product revenue	$ 68,217	$ 51,139	$ 170,241	$ 147,338
Bile acid products
Disaggregation of Revenue [Line Items]
Net product revenue	24,353	22,912	71,291	66,766
Tiopronin products
Disaggregation of Revenue [Line Items]
Net product revenue	29,821	28,227	84,907	80,572
Total net product sales
Disaggregation of Revenue [Line Items]
Net product revenue	$ 54,174	$ 51,139	$ 156,198	$ 147,338
Geographic Concentration Risk \| Revenue from Contract with Customer \| North America
Disaggregation of Revenue [Line Items]
Concentration risk, percentage			99.00%

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8906-108599

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

COLLABORATION AND LICENSE AGREEMENTS (Details) $ in Thousands		3 Months Ended		9 Months Ended
	Sep. 15, 2021 USD ($) performanceObligation	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue		$ 68,217	$ 51,139	$ 170,241	$ 147,338
Deferred revenue, current portion		16,069		16,069		$ 0
License
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue		14,043	$ 0	14,043	$ 0
Collaborative Arrangement \| Vifor Pharma
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Upfront payment	$ 55,000
Maximum milestone payments	$ 845,000
Percentage of royalty on net sales receives	40.00%
Revenue	$ 55,000
Number of performance obligations \| performanceObligation	2
Deferred revenue	$ 42,000	40,200		40,200
Revenue recognized during the period		1,000		1,000
Deferred revenue, current portion		16,100		16,100
Collaborative Arrangement \| Vifor Pharma \| Regulatory and Market Access Milestone
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Maximum milestone payments	135,000
Collaborative Arrangement \| Vifor Pharma \| Sales-based Milestone Payments
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Maximum milestone payments	$ 655,000
Collaborative Arrangement \| Vifor Pharma \| License
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue		$ 13,000		$ 13,000

DEBT SECURITIES - Additional Information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Investments, Debt and Equity Securities [Abstract]
Proceeds from sale of debt securities	$ 376,100
Purchase of debt securities	$ 502,141	$ 143,003

DEBT SECURITIES - Marketable Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Total debt securities	$ 400,857	$ 276,817
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Total debt securities	148,874	135,145
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Total debt securities	227,530	98,646
Securities of government sponsored entities
Debt Securities, Available-for-sale [Line Items]
Total debt securities	$ 24,453	$ 43,026

DEBT SECURITIES - Available for Sale Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, amortized cost basis, current	$ 302,450	$ 271,098
Debt securities, available for sale unrealized gain, current	73	724
Debt securities available for sale unrealized loss, current	(58)	(22)
Debt securities, available-for-sale, current	302,465	271,800
Debt securities, available-for-sale, amortized cost basis, noncurrent	98,416
Debt securities, available for sale unrealized gain, noncurrent	35
Debt securities available for sale unrealized loss, noncurrent	(59)
Debt securities, available-for-sale, noncurrent	98,392
Debt securities, available-for-sale, amortized cost	400,866	276,111
Debt securities, available for sale, unrealized gains	108	728
Debt securities, available-for-sale, unrealized gain (loss)	(117)	(22)
Total available-for-sale securities	400,857	276,817
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, amortized cost basis, current	148,886	135,161
Debt securities, available for sale unrealized gain, current	10	1
Debt securities available for sale unrealized loss, current	(22)	(17)
Debt securities, available-for-sale, current	148,874	135,145
Total available-for-sale securities	148,874	135,145
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, amortized cost basis, current	131,598	92,906
Debt securities, available for sale unrealized gain, current	62	723
Debt securities available for sale unrealized loss, current	(25)	0
Debt securities, available-for-sale, current	131,635	93,629
Debt securities, available-for-sale, amortized cost basis, noncurrent	95,916	5,013
Debt securities, available for sale unrealized gain, noncurrent	35	4
Debt securities available for sale unrealized loss, noncurrent	(56)	0
Debt securities, available-for-sale, noncurrent	95,895	5,017
Total available-for-sale securities	227,530	98,646
Securities of government sponsored entities
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, amortized cost basis, current	21,966	43,031
Debt securities, available for sale unrealized gain, current	1	0
Debt securities available for sale unrealized loss, current	(11)	(5)
Debt securities, available-for-sale, current	21,956	43,026
Debt securities, available-for-sale, amortized cost basis, noncurrent	2,500
Debt securities, available for sale unrealized gain, noncurrent	0
Debt securities available for sale unrealized loss, noncurrent	(3)
Debt securities, available-for-sale, noncurrent	2,497
Total available-for-sale securities	$ 24,453	$ 43,026

DEBT SECURITIES - Securities in an Unrealized Loss Position (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, fair value	$ 197,840	$ 155,174
Less than 12 months, unrealized losses	117	22
12 months or greater, fair value	0	0
12 months or greater, unrealized losses	0	0
Total, fair value	197,840	155,174
Total, unrealized losses	117	22
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, fair value	62,421	112,148
Less than 12 months, unrealized losses	22	17
12 months or greater, fair value	0	0
12 months or greater, unrealized losses	0	0
Total, fair value	62,421	112,148
Total, unrealized losses	22	17
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, fair value	116,042	0
Less than 12 months, unrealized losses	81	0
12 months or greater, fair value	0	0
12 months or greater, unrealized losses	0	0
Total, fair value	116,042	0
Total, unrealized losses	81	0
Securities of government-sponsored entities
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, fair value	19,377	43,026
Less than 12 months, unrealized losses	14	5
12 months or greater, fair value	0	0
12 months or greater, unrealized losses	0	0
Total, fair value	19,377	43,026
Total, unrealized losses	$ 14	$ 5

ACQUISITIONS (Details) - USD ($) $ in Thousands	1 Months Ended
ACQUISITIONS (Details) - USD ($) $ in Thousands	Nov. 30, 2020	Sep. 30, 2021	Dec. 31, 2020
Business Acquisition [Line Items]
Business combination-related contingent consideration		$ 81,400	$ 65,100
Orphan Technologies Limited
Business Acquisition [Line Items]
Cash paid for acquisition	$ 90,000
Closing price adjustments	1,200
Liabilities assumed in acquisition	1,800
Acquisition transaction costs	4,200
Business combination-related contingent consideration	$ 427,000

LEASES - Additional Information (Details) $ in Thousands	3 Months Ended		9 Months Ended
LEASES - Additional Information (Details) $ in Thousands	Sep. 30, 2021 USD ($) lease	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) lease	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)	Apr. 30, 2019 USD ($)
Leases [Abstract]
Number of operating leases \| lease	1		1
ROU asset	$ 23,807		$ 23,807		$ 34,600
Lease liability	36,304		36,304		34,500
Lease incentive, tenant improvements					$ 7,900
Operating lease extension term						5 years
Aggregate base rent						$ 49,500
Operating lease expense	$ 1,200		$ 3,600
Credit to operating lease expense		$ 700		$ 700

LEASES - Future Minimum Rent Commitments (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Leases [Abstract]
2021	$ 1,469
2022	6,020
2023	6,200
2024	6,386
2025	6,578
Thereafter	18,535
Total undiscounted future minimum payments	45,188
Present value discount	(8,884)
Total lease liability	36,304	$ 34,500
Unamortized lease incentives	(6,805)
Cash payments in excess of straight-line lease expense	(5,692)
Total ROU asset	$ 23,807	$ 34,600

LEASES - Supplemental Balance Sheet Information (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Leases [Abstract]
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:OtherAssetsNoncurrent
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesCurrent
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesNoncurrent
Other current liabilities	$ 3,803
Other non-current liabilities	32,501
Total lease liabilities	$ 36,304	$ 34,500

FAIR VALUE MEASUREMENTS - Additional Information (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) business	Sep. 30, 2020 USD ($)	Sep. 10, 2018
Business Acquisition [Line Items]
Number of businesses acquired \| business			2
Fair value of convertible debt	$ 280,100		$ 280,100
Change in fair value of contingent consideration	$ 13,864	$ 5,085	$ 23,960	$ 7,448
Senior Notes \| Senior Notes Due 2025
Business Acquisition [Line Items]
Interest rate percentage	2.50%		2.50%		2.50%

FAIR VALUE MEASUREMENTS - Discount Rates Used (Details)	Sep. 30, 2021	Dec. 31, 2020
Payment Discount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.0580	0.0745
Cholbam \| Revenue Discount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.060	0.065
Chenodal \| Revenue Discount
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.070	0.085

FAIR VALUE MEASUREMENTS - Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Assets:
Cash and cash equivalents	$ 150,327	$ 84,772
Total debt securities	400,857	276,817
Total	551,184	361,589
Liabilities:
Business combination-related contingent consideration	81,400	65,100
Total	81,400	65,100
Quoted prices in active markets (Level 1)
Assets:
Cash and cash equivalents	150,327	84,772
Total debt securities	0	0
Total	150,327	84,772
Liabilities:
Business combination-related contingent consideration	0	0
Total	0	0
Significant other observable inputs (Level 2)
Assets:
Cash and cash equivalents	0	0
Total debt securities	400,857	276,817
Total	400,857	276,817
Liabilities:
Business combination-related contingent consideration	0	0
Total	0	0
Significant unobservable inputs (Level 3)
Assets:
Cash and cash equivalents	0	0
Total debt securities	0	0
Total	0	0
Liabilities:
Business combination-related contingent consideration	81,400	65,100
Total	$ 81,400	$ 65,100

FAIR VALUE MEASUREMENTS - Acquisition-related Contingent Consideration (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Change in fair value of contingent consideration	$ 13,864	$ 5,085	$ 23,960	$ 7,448
Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance			65,100
Change in fair value of contingent consideration			23,960
Contractual payments			(4,883)
Contractual payments included in accrued liabilities at September 30, 2021			(2,662)
Foreign currency impact			(115)
Ending balance	$ 81,400		$ 81,400

INTANGIBLE ASSETS - Additional Information (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Net book value of amortizable intangible assets	$ 148,676	$ 153,189

INTANGIBLE ASSETS - Amortizable Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Finite-lived intangible assets	$ 278,395	$ 264,676
Less: accumulated amortization	(129,719)	(111,487)
Net carrying value	$ 148,676	$ 153,189

INTANGIBLE ASSETS - Amortization (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Finite-Lived Intangible Assets [Line Items]
Total amortization expense	$ 6,344	$ 6,023	$ 18,432	$ 16,482
Research and development
Finite-Lived Intangible Assets [Line Items]
Total amortization expense	292	292	866	870
Selling, general and administrative
Finite-Lived Intangible Assets [Line Items]
Total amortization expense	$ 6,052	$ 5,731	$ 17,566	$ 15,612

CONVERTIBLE NOTES PAYABLE - Additional Information (Details) $ / shares in Units, $ in Millions		9 Months Ended
	Sep. 10, 2018 USD ($)	Sep. 30, 2021 USD ($) day $ / shares
Debt Instrument [Line Items]
Fair value of convertible debt		$ 280.1
Senior Notes \| Senior Notes Due 2025
Debt Instrument [Line Items]
Long-term debt, excluding current maturities	$ 276.0	$ 276.0
Interest rate percentage	2.50%	2.50%
Proceeds from issuance of debt	$ 267.2
Debt instrument, convertible, threshold percentage of stock price trigger		130.00%
Conversion ratio		0.0257739
Conversion price (in dollars per share) \| $ / shares		$ 38.80
Convertible debt, market price (in dollars per share) \| $ / shares		$ 1.015
Debt conversion, liability		$ 198.6
Debt conversion, equity		$ 77.4
Debt instrument term		7 years
Debt issuance costs, net		$ 8.8
Debt instrument, interest rate, effective percentage		7.70%
Debt redeemable upon bankruptcy insolvency		100.00%
Senior Notes \| Convertible Notes Due 2019
Debt Instrument [Line Items]
Interest rate percentage	4.50%
Debt instrument, repurchase amount	$ 23.4
Senior Notes \| Convertible Notes Due 2019 \| Debt Conversion, Scenario One
Debt Instrument [Line Items]
Debt instrument, convertible, threshold trading days \| day		20
Debt instrument, convertible, threshold consecutive trading days \| day		30
Debt instrument, convertible, threshold percentage of stock price trigger		130.00%
Senior Notes \| Convertible Notes Due 2019 \| Debt Conversion, Scenario Two
Debt Instrument [Line Items]
Debt instrument, convertible, threshold trading days \| day		5
Debt instrument, convertible, threshold consecutive trading days \| day		10
Debt instrument, convertible, threshold percentage of stock price trigger		98.00%

CONVERTIBLE NOTES PAYABLE - Composition of Notes (Details) - Senior Notes - Senior Notes Due 2025 - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020	Sep. 10, 2018
Debt Instrument [Line Items]
Interest rate percentage	2.50%		2.50%
2.50% convertible senior notes due 2025	$ 276,000	$ 276,000
Unamortized debt discount	(48,704)	(56,384)
Unamortized debt issuance costs	(3,600)	(4,277)
Total 2025 Notes, net of unamortized debt discount and debt issuance costs	$ 223,696	$ 215,339

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References + Details

CONVERTIBLE NOTES PAYABLE - Schedule of Interest Expense (Details) - Senior Notes - Senior Notes Due 2025 - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Debt Instrument [Line Items]
Contractual interest expense	$ 1,725	$ 1,725	$ 5,175	$ 5,175
Amortization of debt discount	2,609	2,417	7,680	7,115
Amortization of debt issuance costs	226	225	677	674
Total interest expense for the 2025 Notes	$ 4,560	$ 4,367	$ 13,532	$ 12,964

ACCRUED EXPENSES (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Payables and Accruals [Abstract]
Government rebates payable	$ 11,311	$ 10,707
Compensation related costs	16,896	17,912
Accrued royalties and contingent consideration	8,360	7,857
Research and development	22,163	10,166
Selling, general and administrative	3,117	3,944
Miscellaneous accrued expenses	1,461	6,207
Total accrued expenses	$ 63,308	$ 56,793

NET LOSS PER COMMON SHARE - EPS Reconciliation (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share [Abstract]
Basic shares outstanding (in shares)	60,803,045	50,929,575	59,230,881	46,289,103
Diluted shares outstanding (in shares)	60,803,045	50,929,575	59,230,881	46,289,103
Net loss	$ (35,639)	$ (22,549)	$ (128,518)	$ (47,809)
Basic net loss per common share (in dollars per share)	$ (0.59)	$ (0.44)	$ (2.17)	$ (1.03)
Diluted net loss per common share (in dollars per share)	$ (0.59)	$ (0.44)	$ (2.17)	$ (1.03)

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 40
-Section 65
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-Subparagraph (e)(4)
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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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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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 COMMON SHARE - Antidilutive Shares (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Total anti-dilutive shares
Anti-dilutive shares excluded from the calculation (in shares)	17,984,802	16,911,846	18,012,120	16,849,452
Restricted stock
Total anti-dilutive shares
Anti-dilutive shares excluded from the calculation (in shares)	1,538,792	1,400,555	1,588,737	1,384,748
Convertible debt
Total anti-dilutive shares
Anti-dilutive shares excluded from the calculation (in shares)	7,113,402	7,113,402	7,113,402	7,113,402
Options
Total anti-dilutive shares
Anti-dilutive shares excluded from the calculation (in shares)	9,332,608	8,397,889	9,309,981	8,351,302

SHARE-BASED COMPENSATION - Service Based Restricted Stock Activity (Details) - Restricted stock units $ / shares in Units, $ in Millions	9 Months Ended
	Sep. 30, 2021 USD ($) $ / shares shares
Number of Restricted Stock Units
Beginning balance (in shares) \| shares	1,109,942
Granted (in shares) \| shares	859,373
Vested (in shares) \| shares	(383,211)
Forfeited/canceled (in shares) \| shares	(132,147)
Ending balance (in share) \| shares	1,453,957
Weighted Average Grant Date Fair Value
Beginning balance (in dollars per share) \| $ / shares	$ 17.84
Granted (in dollars per share) \| $ / shares	24.87
Vested (in dollars per share) \| $ / shares	18.09
Forfeited/canceled (in dollars per share) \| $ / shares	21.57
Ending balance (in dollars per share) \| $ / shares	$ 21.59
Unamortized stock compensation expense \| $	$ 25.2
Weighted-average recognition period (in years)	2 years 7 months 6 days

SHARE-BASED COMPENSATION - Performance Based Restricted Stock Activity (Details) - Performance Shares $ / shares in Units, $ in Millions	9 Months Ended
	Sep. 30, 2021 USD ($) $ / shares shares
Number of Restricted Stock Units
Beginning balance (in shares) \| shares	167,500
Granted (in shares) \| shares	0
Vested (in shares) \| shares	(115,000)
Forfeited/canceled (in shares) \| shares	0
Ending balance (in share) \| shares	52,500
Weighted Average Grant Date Fair Value
Beginning balance (in dollars per share) \| $ / shares	$ 16.48
Granted (in dollars per share) \| $ / shares	0
Vested (in dollars per share) \| $ / shares	15.46
Forfeited/canceled (in dollars per share) \| $ / shares	0
Ending balance (in dollars per share) \| $ / shares	$ 18.73
Unamortized stock compensation expense \| $	$ 0.1
Weighted-average recognition period (in years)	9 months 18 days

SHARE-BASED COMPENSATION - Stock Option Activity (Details) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2021 USD ($) $ / shares shares	Dec. 31, 2020 USD ($) $ / shares shares
Weighted Average Exercise Price
Number of shares exercisable (in shares) \| shares	6,100,000
Weighted average exercise price (in dollars per share) \| $ / shares	$ 19.33
Stock Options
Shares Underlying Options
Beginning balance (in shares) \| shares	8,242,996
Granted (in shares) \| shares	1,723,807
Exercised (in shares) \| shares	(456,014)
Forfeited/canceled (in shares) \| shares	(387,875)
Ending balance (in shares) \| shares	9,122,914	8,242,996
Weighted Average Exercise Price
Beginning balance (in dollars per share) \| $ / shares	$ 18.97
Granted (in dollars per share) \| $ / shares	25.23
Exercised (in dollars per share) \| $ / shares	14.65
Forfeited/canceled (in dollars per share) \| $ / shares	23.87
Ending balance (in dollars per share) \| $ / shares	$ 20.17	$ 18.97
Weighted Average Remaining Contractual Life (years)	6 years 4 months 9 days	6 years 5 months 4 days
Aggregate Intrinsic Value \| $	$ 47,013	$ 71,641
Unamortized stock compensation expense \| $	$ 34,000
Weighted-average recognition period (in years)	2 years 7 months 6 days

SHARE-BASED COMPENSATION - Stock based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 6,986	$ 5,398	$ 22,190	$ 17,262
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	2,630	2,510	8,477	6,968
Selling, general & administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 4,356	$ 2,888	$ 13,713	$ 10,294

INCOME TAXES (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
INCOME TAXES (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Income tax expense (benefit)	$ 43	$ 23	$ 405	$ (18,888)

- Definition

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

+ References + Details

INVENTORY (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Inventory Disclosure [Abstract]
Raw materials	$ 3,819	$ 3,219
Finished goods	2,797	4,389
Total inventory	6,616	7,608
Inventory reserve	$ 3,600	$ 3,600

ACCOUNTS RECEIVABLE (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Receivables [Abstract]
Accounts receivable, net	$ 13,370	$ 15,925

EQUITY OFFERINGS (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended		3 Months Ended	8 Months Ended	9 Months Ended
	Feb. 28, 2021	Jun. 30, 2020	Mar. 31, 2021	Sep. 30, 2021	Sep. 30, 2021	Sep. 30, 2020	May 18, 2021	May 17, 2021	Dec. 31, 2020	Feb. 29, 2020
Class of Stock [Line Items]
Common stock shares authorized (in shares)				200,000,000	200,000,000		200,000,000	100,000,000	100,000,000
Underwritten Equity Offering
Class of Stock [Line Items]
Shares authorized in sale (in shares)	7,500,000	7,500,000
Sales price per share (in dollars per share)	$ 26.75	$ 15.50
Proceeds from issuance of common stock	$ 189,300	$ 108,700			$ 189,278	$ 108,692
At-The-Market Offering
Class of Stock [Line Items]
Shares authorized in sale (in shares)			184,186	1,051,992
Proceeds from issuance of common stock			$ 4,900	$ 28,600	4,878	$ 0
Aggregate offering amount authorized										$ 100,000
Amount previously sold				28,600	28,600
Remaining offering amount authorized				$ 71,400	$ 71,400