Harmony Biosciences (HRMY) 10-Q 6 Aug 24 2024 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2024	Aug. 02, 2024
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2024
Document Transition Report	false
Entity File Number	001-39450
Entity Registrant Name	HARMONY BIOSCIENCES HOLDINGS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	82-2279923
Entity Address, Postal Zip Code	19462
Entity Address, Address Line One	630 W.
Entity Address, Address Line Two	Germantown Pike
Entity Address, Address Line Three	Suite 215
Entity Address, City or Town	Plymouth Meeting
Entity Address, State or Province	PA
City Area Code	484
Local Phone Number	539-9800
Title of 12(b) Security	Common Stock, par value $0.00001 value per share
Trading Symbol	HRMY
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		56,834,745
Entity Central Index Key	0001802665
Document Fiscal Period Focus	Q2
Document Fiscal Year Focus	2024
Current Fiscal Year End Date	--12-31
Amendment Flag	false

UNAUDITED CONDENSED CONSOLIDATE

UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
CURRENT ASSETS:
Cash and cash equivalents	$ 317,296	$ 311,660
Investments, short-term	29,614	41,800
Trade receivables, net	83,157	74,140
Inventory, net	5,643	5,363
Prepaid expenses	16,127	12,570
Other current assets	6,507	5,537
Total current assets	458,344	451,070
NONCURRENT ASSETS:
Property and equipment, net	754	371
Restricted cash	270	270
Investments, long-term	87,178	72,169
Intangible assets, net	125,186	137,108
Deferred tax asset	180,186	144,162
Other noncurrent assets	6,465	6,298
Total noncurrent assets	400,039	360,378
TOTAL ASSETS	858,383	811,448
CURRENT LIABILITIES:
Trade payables	22,683	17,730
Accrued compensation	9,641	23,747
Accrued expenses	91,644	99,494
Current portion of long-term debt	15,000	15,000
Other current liabilities	7,614	7,810
Total current liabilities	146,582	163,781
NONCURRENT LIABILITIES:
Long-term debt, net	171,422	178,566
Other noncurrent liabilities	1,796	2,109
Total noncurrent liabilities	173,218	180,675
TOTAL LIABILITIES	319,800	344,456
COMMITMENTS AND CONTINGENCIES (Note 13)
STOCKHOLDERS' EQUITY:
Common stock-$0.00001 par value; 500,000,000 shares authorized at June 30, 2024 and December 31, 2023, respectively; 56,833,771 and 56,769,081 shares issued and outstanding at June 30, 2024 and December 31, 2023, respectively	1	1
Additional paid in capital	632,168	610,266
Accumulated other comprehensive (loss) income	(234)	2
Accumulated deficit	(93,352)	(143,277)
TOTAL STOCKHOLDERS' EQUITY	538,583	466,992
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 858,383	$ 811,448

UNAUDITED CONDENSED CONSOLIDA_2

UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Jun. 30, 2024	Dec. 31, 2023
UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS
Common stock, par value	$ 0.00001	$ 0.00001
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	56,833,771	56,769,081
Common stock, shares outstanding	56,833,771	56,769,081

UNAUDITED CONDENSED CONSOLIDA_3

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME
Net product revenue	$ 172,814	$ 134,216	$ 327,429	$ 253,342
Revenue from Contract with Customer, Product and Service [Extensible Enumeration]	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember
Cost of product sold	$ 32,144	$ 25,008	$ 59,628	$ 45,788
Cost, Product and Service [Extensible Enumeration]	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember
Gross profit	$ 140,670	$ 109,208	$ 267,801	$ 207,554
Operating expenses:
Research and development	63,583	14,969	85,772	28,258
Sales and marketing	28,507	24,528	55,740	47,100
General and administrative	27,224	22,809	52,900	44,871
Total operating expenses	119,314	62,306	194,412	120,229
Operating income	21,356	46,902	73,389	87,325
Other (expense) income, net	37	(31)	(104)	(29)
Interest expense	(4,404)	(6,218)	(8,939)	(11,949)
Interest income	4,705	3,442	9,133	6,528
Income before income taxes	21,694	44,095	73,479	81,875
Income tax expense	(10,103)	(9,795)	(23,554)	(18,090)
Net income	11,591	34,300	49,925	63,785
Unrealized (loss) income on investments	(63)	(491)	(236)	(371)
Comprehensive income	$ 11,528	$ 33,809	$ 49,689	$ 63,414
EARNINGS PER SHARE:
Basic	$ 0.20	$ 0.57	$ 0.88	$ 1.07
Diluted	$ 0.20	$ 0.56	$ 0.87	$ 1.05
Weighted average number of shares of common stock - basic	56,802,357	59,974,123	56,786,873	59,853,808
Weighted average number of shares of common stock - diluted	57,541,696	60,743,953	57,571,570	60,997,410

UNAUDITED CONDENSED CONSOLIDA_4

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock	Additional paid-in capital	Accumulated other comprehensive (loss) income	Accumulated deficit	Total
Beginning balance at Dec. 31, 2022	$ 1	$ 675,118	$ (151)	$ (272,130)	$ 402,838
Beginning balance, shares at Dec. 31, 2022	59,615,731
Net Income (Loss)				63,785	63,785
Unrealized loss on investments			(371)		(371)
Exercise of stock options		4,069			4,069
Exercise of stock options , Shares	383,927
Stock-based compensation		14,851			14,851
Ending balance at Jun. 30, 2023	$ 1	694,038	(522)	(208,345)	485,172
Ending balance, shares at Jun. 30, 2023	59,999,658
Beginning balance at Mar. 31, 2023	$ 1	685,716	(31)	(242,645)	443,041
Beginning balance, shares at Mar. 31, 2023	59,954,618
Net Income (Loss)				34,300	34,300
Unrealized loss on investments			(491)		(491)
Exercise of stock options		674			674
Exercise of stock options , Shares	45,040
Stock-based compensation		7,648			7,648
Ending balance at Jun. 30, 2023	$ 1	694,038	(522)	(208,345)	485,172
Ending balance, shares at Jun. 30, 2023	59,999,658
Beginning balance at Dec. 31, 2023	$ 1	610,266	2	(143,277)	466,992
Beginning balance, shares at Dec. 31, 2023	56,769,081
Net Income (Loss)				49,925	49,925
Unrealized loss on investments			(236)		(236)
Exercise of options and restricted stock units		420			$ 420
Exercise of options and restricted stock units, Shares	64,690
Exercise of stock options , Shares					46,996
Stock-based compensation		21,482			$ 21,482
Ending balance at Jun. 30, 2024	$ 1	632,168	(234)	(93,352)	538,583
Ending balance, shares at Jun. 30, 2024	56,833,771
Beginning balance at Mar. 31, 2024	$ 1	620,507	(171)	(104,943)	515,394
Beginning balance, shares at Mar. 31, 2024	56,791,214
Net Income (Loss)				11,591	11,591
Unrealized loss on investments			(63)		(63)
Exercise of stock options		573			573
Exercise of stock options , Shares	42,557
Stock-based compensation		11,088			11,088
Ending balance at Jun. 30, 2024	$ 1	$ 632,168	$ (234)	$ (93,352)	$ 538,583
Ending balance, shares at Jun. 30, 2024	56,833,771

UNAUDITED CONDENSED CONSOLIDA_5

UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 49,925	$ 63,785
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation	254	206
Intangible amortization	11,922	11,922
Acquired in-process research & development (IPR&D) expense	42,595
Stock-based and employee stock purchase compensation expense	21,482	14,851
Stock appreciation rights market adjustment	(85)	(497)
Debt issuance costs amortization	356	840
Deferred taxes	(17,756)	(7,635)
Amortization of premiums and accretion of discounts on Investment securities	(1,220)	(1,312)
Other non-cash expenses	1,126	799
Change in operating assets and liabilities:
Trade receivables	(9,017)	(9,072)
Inventory	(280)	(557)
Prepaid expenses and other assets	(4,004)	2,227
Trade payables	3,555	2,777
Other liabilities	(25,095)	1,288
Net cash provided by operating activities	73,758	79,622
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of investment securities	(46,317)	(72,847)
Proceeds from maturities and sales of investment securities	44,481	63,491
Purchase of property and equipment	(637)	(205)
Acquisition of Zynerba Pharmaceuticals, Inc., net of cash acquired	(33,069)
Payment of license fee	(25,500)
Net cash used in investing activities	(61,042)	(9,561)
CASH FLOWS FROM FINANCING ACTIVITIES:
Principal repayment of long term debt	(7,500)	(1,000)
Payments of employee withholding taxes related to stock-based awards	(269)	(514)
Proceeds from exercised options	689	4,584
Net cash (used in) provided by financing activities	(7,080)	3,070
NET INCREASE IN CASH, CASH EQUIVALENTS, AND RESTRICTED CASH	5,636	73,131
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH-Beginning of period	311,930	244,534
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH-End of period	317,566	317,665
Supplemental Disclosure of Cash Flow Information:
Cash paid during the year for interest	8,944	10,691
Cash paid during the year for taxes	$ 42,093	$ 19,890

ORGANIZATION AND DESCRIPTION OF

ORGANIZATION AND DESCRIPTION OF BUSINESS	6 Months Ended
	Jun. 30, 2024
ORGANIZATION AND DESCRIPTION OF BUSINESS
ORGANIZATION AND DESCRIPTION OF BUSINESS	1. ORGANIZATION AND DESCRIPTION OF BUSINESS The Company Harmony Biosciences Holdings, Inc., and its consolidated subsidiaries (the “Company”), was founded in July 2017 as Harmony Biosciences II, LLC, a Delaware limited liability company. The Company converted to a Delaware corporation named Harmony Biosciences II, Inc. in September 2017 and, in February 2020, the Company changed its name to Harmony Biosciences Holdings, Inc. The Company’s operations are conducted in its wholly owned subsidiaries, Harmony Biosciences, LLC (“Harmony”), and Harmony Biosciences Management, Inc. The Company is a commercial-stage pharmaceutical company focused on developing and commercializing innovative therapies for patients living with rare neurological disorders as well as patients living with other neurological diseases who have unmet medical needs. The Company is headquartered in Plymouth Meeting, Pennsylvania. On October 10, 2023, the Company completed a tender offer to acquire all of the outstanding shares of common stock of Zynerba Pharmaceuticals, Inc. (together with its subsidiary, Zynerba Pharmaceutical Pty, Ltd., “Zynerba”). Zynerba is a clinical-stage pharmaceutical company focused on innovative pharmaceutically produced transdermal cannabidiol therapies for orphan neurobehavioral disorders, including Fragile X Syndrome. As of July 1, 2024, Zynerba was renamed and is known as Harmony Biosciences Management, Inc. On April 30, 2024, the Company acquired all of the issued and outstanding capital stock of Epygenix Therapeutics, Inc., a Wyoming corporation (“Epygenix”). As a result, the Company now has an exclusive license relating to the use of clemizole, initially for the treatment of Dravet Syndrome and Lennox-Gastaut Syndrome.

LIQUIDITY AND CAPITAL RESOURCES

LIQUIDITY AND CAPITAL RESOURCES	6 Months Ended
	Jun. 30, 2024
LIQUIDITY AND CAPITAL RESOURCES
LIQUIDITY AND CAPITAL RESOURCES	2. The unaudited condensed consolidated financial statements have been prepared as though the Company will continue as a going concern, which contemplates the realization of assets and satisfaction of liabilities in the normal course of business. The Company had an accumulated deficit of $93,352 and $143,277, as of June 30, 2024, and December 31, 2023, respectively. As of June 30, 2024, the Company had cash, cash equivalents and investments of $434,088. The Company believes that its existing cash, cash equivalents and investments on hand as of June 30, 2024, as well as additional cash generated from operating and financing activities will meet its operational liquidity needs and fund its planned investing activities for the next twelve months from the date of issuance of these unaudited condensed consolidated financial statements.

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	6 Months Ended
	Jun. 30, 2024
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	3. Basis of Presentation The unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”) and include all adjustments necessary for the fair presentation of the Company’s financial position for the periods presented. All intercompany accounts and transactions have been eliminated in consolidation. The unaudited condensed consolidated balance sheet as of June 30, 2024, the unaudited condensed consolidated statements of cash flows for the six months ended June 30, 2024, and 2023, and the unaudited condensed consolidated statements of operations and comprehensive income and the unaudited condensed consolidated statements of shareholders’ equity for the three and six months ended June 30, 2024, and 2023, are unaudited. The balance sheet as of December 31, 2023, was derived from audited financial statements as of and for the year ended December 31, 2023. The unaudited interim condensed consolidated financial statements have been prepared on the same basis as the audited annual financial statements as of and for the year ended December 31, 2023, and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair presentation of the Company’s financial position as of June 30, 2024, and the results of its operations and its cash flows for the three and six months ended June 30, 2024, and 2023. The unaudited condensed consolidated results of operations are not necessarily indicative of the results that may occur for the full fiscal year. Certain information and disclosures normally included in the financial statements prepared in accordance with GAAP have been condensed or omitted under the SEC’s rules and regulations. These unaudited condensed consolidated financial statements should be read in conjunction with the audited financial statements and accompanying notes thereto contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023. Reclassifications Certain prior period amounts within the unaudited condensed consolidated statements of operations and comprehensive income have been reclassified to conform to current period presentation. In particular, interest expense and interest income were previously classified together as interest expense, net and are now separately classified as interest expense and interest income, respectively. The reclassification of these items had no impact on net income, earnings per share or accumulated deficit in current or prior periods. Significant Risks and Uncertainties The Company’s operations are subject to a number of factors that can affect its operating results and financial condition. Such factors include, but are not limited to, clinical trial results of the Company’s product candidates; the Company’s ability to obtain regulatory approval to market its products; competition from products manufactured and sold or being developed by other companies; the price of, and demand for, the Company’s products, if approved; the Company’s ability to negotiate favorable licensing or other manufacturing and marketing agreements for its product candidates. The Company currently has one commercially approved product, WAKIX, and there can be no assurance that the Company’s research and development efforts will result in successfully commercialized products in addition to WAKIX. Developing and commercializing a product requires significant time and capital and is subject to regulatory review and approval as well as competition from other biotechnology and pharmaceutical companies. The Company operates in an environment of rapid change and is dependent upon the continued services of its employees and consultants and obtaining and protecting intellectual property. ​ Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts and disclosures in the unaudited condensed consolidated financial statements, including the notes thereto, and elsewhere in this report. Actual results may differ significantly from estimates, which include rebates due pursuant to commercial and government contracts, accrued research and development expenses, stock-based compensation expense and income taxes. Operating Segments The Company holds all its tangible assets, conducts its operations, and generates its revenue in the United States. Operating segments are defined as components of an entity for which separate financial information is available and that is regularly reviewed by the Chief Operating Decision Makers in deciding how to allocate resources to an individual segment and in assessing performance. The Company has determined it operates in a single operating segment and has one reportable segment. ​ Fair Value of Financial Instruments The Company’s unaudited condensed consolidated financial statements include cash, cash equivalents, restricted cash, accounts payable, and accrued liabilities, all of which are short term in nature and, accordingly, approximate fair value. It is the Company’s policy to measure non-financial assets and liabilities at fair value on a nonrecurring basis. These non-financial assets and liabilities are not measured at fair value on an ongoing basis but are subject to fair value adjustments in certain circumstances (such as evidence of impairment), which, if material, are disclosed in the accompanying footnotes. The Company measures certain assets and liabilities at fair value based on the fair value hierarchy that prioritizes inputs to valuation techniques used to measure fair value into three levels based on the source of inputs as follows: Level 1—Valuations based on unadjusted quoted prices in active markets for identical assets or liabilities. Level 2—Valuations based on observable inputs and quoted prices in active markets for similar assets and liabilities. Level 3—Valuations based on unobservable inputs and models that are supported by little or no market activity. Money market funds are classified as Level 1 fair value instruments. Investments in available-for-sale debt securities are classified as Level 2 and carried at fair value, which we estimate utilizing a third-party pricing service. The pricing service utilizes industry standard valuation models whereby all significant inputs, including benchmark yields, reported trades, broker/dealer quotes, issuer spreads, bids, offers, or other market-related data, are observable. We validate valuations obtained from third-party services by obtaining market values from other pricing sources. The Company did not classify any assets or liabilities as Level 3 as of June 30, 2024, or December 31, 2023. Cash, Cash Equivalents and Restricted Cash Cash and cash equivalents and restricted cash consist of cash and, if applicable, highly liquid investments with an original maturity of three months or less when purchased, including investments in Money Market Funds and debt securities that approximate fair value. The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the balance sheet and the statements of cash flows. ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ June 30, December 31, ​ ​ 2024 ​ 2023 Cash and cash equivalents ​ $ 317,296 ​ $ 311,660 Restricted cash ​ 270 ​ 270 Total cash, cash equivalents, and restricted cash shown in the statements of cash flows ​ $ 317,566 ​ $ 311,930 ​ Restricted cash includes amounts required to be held as a security deposit in the form of letters of credit for the Company’s credit card program and the fleet program. Investments The Company’s investments consist of debt securities that are classified as available-for-sale. Short-term and long-term investments are carried at fair value and unrealized gains and losses are recorded as a component of accumulated comprehensive income in stockholders’ equity. Interest income earned on cash and investment balances, accretion of the discount on investments in debt securities, amortization of premiums and realized gains and losses, if any, are recorded in interest income on the unaudited condensed consolidated statement of operations and comprehensive income. Realized gains and losses that result from the sale of investments are determined on a specific identification basis. At each reporting period, the Company reviews any unrealized losses position to determine if the decline in the fair value of the underlying investments is a result of credit losses or other factors. If the assessment indicates that a credit loss exists, any impairment is recognized as an allowance for credit losses in our consolidated statement of operations. Concentrations of Risk Substantially all of the Company’s cash and money market funds are held in five financial institutions. Due to their size, the Company believes these financial institutions represent minimal credit risk. Deposits may exceed the amount of insurance provided on such deposits by the Federal Deposit Insurance Corporation for U.S. institutions. The Company has not experienced any losses on its deposits of cash and cash equivalents. The Company believes that it is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held. The Company is subject to credit risk from its trade receivables related to its product sales. The Company extends credit to specialty pharmaceutical distribution companies within the United States. Customer creditworthiness is monitored, and collateral is not required. Historically, the Company has not experienced credit losses on its accounts receivable. The Company monitors its exposure within accounts receivable and would record a reserve against uncollectible accounts receivable if necessary. As of June 30, 2024, three customers accounted for 100% of gross accounts receivable; Caremark LLC (“CVS Caremark”), which accounted for 41% of gross accounts receivable; Accredo Health Group, Inc. (“Accredo”), which accounted for 35% of gross accounts receivable; and PANTHERx Specialty Pharmacy LLC (“Pantherx”), which accounted for 24% of gross accounts receivable. As of December 31, 2023, three customers accounted for 100% of gross accounts receivable; Accredo, which accounted for 39% of gross accounts receivable, CVS Caremark, which accounted for 32% of gross accounts receivable; and Pantherx, which accounted for 29% of gross accounts receivable. For the six months ended June 30, 2024, three customers accounted for 100% of gross product revenue; CVS Caremark accounted for 40% of gross product revenue; Accredo accounted for 33% of gross product revenue; and Pantherx accounted for 27% of gross product revenue. For the six months ended June 30, 2023, three customers accounted for 100% of gross product revenue; CVS Caremark accounted for 35% of gross product revenue; Pantherx accounted for 33% of gross product revenue; and Accredo accounted for 32% of gross product revenue. The Company depends on a single supplier for its product and a single supplier for its active pharmaceutical ingredient. Share Repurchases The Company accounts for share repurchases as constructive retirements, whereby it reduces common stock and additional paid-in capital by the amount of the original issuance, with any excess purchase price recorded as a reduction to retained earnings. Under this method, issued and outstanding shares of common stock are reduced by the amount of shares of common stock repurchased, and no treasury stock is recognized on the condensed consolidated financial statements. ​ ​ ​ Business Combinations Business combinations and asset acquisitions are accounted for in accordance with FASB ASC 805 Business Combinations. Refer to Note 4, Acquisitions ​ Recently Issued Accounting Pronouncements In November 2023, the FASB issued Accounting Standards Update (“ASU”) No. 2023-07, Improvements to Reportable Segment Disclosures ​ In December 2023, the FASB issued Accounting Standards Update (“ASU”) No 2023-09, “Income Taxes (Topic 740): Improvements to Income Tax Disclosures”

ACQUISITIONS

ACQUISITIONS	6 Months Ended
	Jun. 30, 2024
ACQUISITIONS
ACQUISITIONS	4. ACQUISITIONS Acquisition of Zynerba In October 2023, the Company completed a tender offer to purchase the outstanding common stock of Zynerba (“Zynerba Common Stock”) for (i) $1.1059 per share of Zynerba Common Stock (the “Common Cash Amount”), the aggregate amount of which was $60,000 and was paid at closing, plus (ii) one contingent value right (each, a “CVR”) per share of Zynerba Common Stock (the “Common CVR Amount”), which represents the right to receive up to approximately $2.5444 per share of Zynerba Common Stock, subject to the achievement of certain clinical, regulatory and sales-based milestones. The Common CVR Amounts are to be paid in cash, subject to any applicable withholding of taxes and without interest. The aggregate amount of consideration to acquire Zynerba Common Stock was $60,000, excluding transaction related fees of $2,645 and was paid by the Company using cash on hand. The Zynerba Acquisition was accounted for as an asset acquisition under ASC Topic 805, Business Combinations, because substantially all of the fair value of the gross assets acquired was concentrated in a single identifiable IPR&D asset, ZYN002, Zynerba’s lead asset. ZYN002 is the first and only pharmaceutically manufactured, synthetic cannabidiol, devoid of THC, formulated as a patent-protected permeation-enhanced gel for transdermal delivery through the skin and into the circulatory system and is currently in Phase III clinical trial for the potential treatment of Fragile X Syndrome. The Company recognized the acquired assets and assumed liabilities based on the consideration paid, including transaction costs, on a relative fair value basis, and after first allocating the preliminary excess of the fair value of net assets acquired over the purchase price consideration to certain qualifying assets, principally, the IPR&D asset. Acquisition of Epygenix On April 30, 2024, the Company acquired all of the issued and outstanding capital stock of Epygenix pursuant to the terms of a stock purchase agreement. In connection with the closing of the transaction, the Company paid the former stockholders of Epygenix up front consideration of $35,000 less a working capital adjustment. In addition, the Company will be obligated to pay up to $130,000 upon the achievement of development and regulatory milestones and up to $515,000 upon the achievement of certain sales-based milestones, in each case to Epygenix’s former stockholders. As a result, the Company now has an exclusive license relating to the use of clemizole, initially for the treatment of Dravet Syndrome and Lennox-Gastaut Syndrome. The total purchase consideration for Epygenix was as follows: ​ ​ ​ ​ ​ Cash consideration paid to selling shareholders and to settle restricted stock units ("RSUs") ​ $ 32,686 Transaction costs ​ ​ 450 Total purchase consideration ​ $ 33,136 ​ The acquisition of Epygenix was accounted for as an asset acquisition under ASC Topic 805, Business Combinations. The Company did not acquire any outputs and there was not an acquired substantive process in place to create outputs. The Company recognized the acquired assets and assumed liabilities based on the consideration paid, including transaction costs, on a relative fair value basis, and after first allocating the preliminary excess of the fair value of net assets acquired over the purchase price consideration to certain qualifying assets, principally, the IPR&D asset. In accordance with the accounting for asset acquisitions, an entity that acquires IPR&D assets in an asset acquisition follows the guidance in ASC Topic 730, Research and Development, which requires that both tangible and intangible identifiable research and development assets with no alternative future use be allocated a portion of the consideration transferred and recorded as research and development expense at the acquisition date. As a result, the Company recorded a charge of $17,095 related to acquired in-process research and development expense during the three and six months ended June 30, 2024. ​ ​ ​ ​ ​ Assets acquired ​ ​ ​ Acquired in-process research and development ​ $ 17,095 Deferred tax asset ​ ​ 18,268 Other assets ​ ​ 590 Total assets acquired ​ $ 35,953 Total liabilities assumed ​ $ 2,817 ​ ​ ​ ​ Net assets acquired ​ $ 33,136 ​

INVESTMENTS

INVESTMENTS	6 Months Ended
	Jun. 30, 2024
INVESTMENTS
INVESTMENTS	5. INVESTMENTS ​ The carrying value and amortized cost of the Company’s available-for-sale debt securities, summarized by type of security, consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, 2024 ​ ​ Amortized ​ Unrealized ​ Unrealized ​ ​ Fair ​ ​ Cost ​ Gains ​ Losses ​ ​ Value Short-term: ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial paper $ 16,175 ​ 1 ​ (5) ​ $ 16,171 Corporate debt securities ​ 13,443 ​ 4 ​ (4) ​ ​ 13,443 Total short-term investments $ 29,618 ​ 5 ​ (9) ​ $ 29,614 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Long-term: ​ ​ ​ ​ ​ ​ ​ ​ ​ Corporate debt securities ​ 59,793 ​ 37 ​ (87) ​ ​ 59,743 U.S. government securities ​ 27,615 ​ — ​ (180) ​ ​ 27,435 Total long-term investments $ 87,408 ​ 37 ​ (267) ​ $ 87,178 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2023 ​ ​ Amortized ​ Unrealized ​ Unrealized ​ ​ Fair ​ ​ Cost ​ Gains ​ Losses ​ ​ Value Short-term: ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial paper $ 23,832 ​ 36 ​ (3) ​ $ 23,865 Corporate debt securities ​ 15,968 ​ 28 ​ — ​ ​ 15,996 U.S. government securities ​ 1,940 ​ — ​ (1) ​ ​ 1,939 Total short-term investments $ 41,740 ​ 64 ​ (4) ​ $ 41,800 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Long-term: ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial paper $ 744 ​ — ​ — ​ $ 744 Corporate debt securities ​ 42,688 ​ 81 ​ (28) ​ ​ 42,741 U.S. government securities ​ 28,795 ​ 7 ​ (118) ​ ​ 28,684 Total long-term investments $ 72,227 ​ 88 ​ (146) ​ $ 72,169 ​ The Company classifies investments with an original maturity of less than one year as current and investments with an original maturity date of greater than one year as noncurrent on its unaudited condensed consolidated balance sheet. The investments classified as noncurrent have original maturity dates ranging from 1-2 years. The Company did not have any available-for-sale debt security investments in a continuous unrealized loss position of greater than 12 months as of June 30, 2024, and December 31, 2023, respectively.

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	6 Months Ended
	Jun. 30, 2024
FAIR VALUE MEASUREMENTS
FAIR VALUE MEASUREMENTS	6. FAIR VALUE MEASUREMENTS Money market funds are classified as Level 1 fair value instruments. Investments in available-for-sale debt securities are classified as Level 2 and carried at fair value, which we estimate utilizing a third-party pricing service. The pricing service utilizes industry standard valuation models whereby all significant inputs, including benchmark yields, reported trades, broker/dealer quotes, issuer spreads, bids, offers, or other market-related data, are observable. We validate valuations obtained from third-party services by obtaining market values from other pricing sources. The Company did not classify any assets or liabilities as Level 3 as of June 30, 2024, or December 31, 2023. The Company’s assets measured at fair value consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, 2024 ​ December 31, 2023 ​ ​ Total ​ Level 1 ​ Level 2 ​ ​ Total ​ Level 1 ​ Level 2 Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash equivalents $ 270,989 ​ 270,989 ​ — ​ $ 244,569 ​ 243,685 ​ 884 Commercial paper ​ 16,171 ​ — ​ 16,171 ​ ​ 24,609 ​ — ​ 24,609 Corporate debt securities ​ 73,186 ​ — ​ 73,186 ​ ​ 58,737 ​ — ​ 58,737 U.S. government securities ​ 27,435 ​ — ​ 27,435 ​ ​ 30,623 ​ — ​ 30,623 Total $ 387,781 ​ 270,989 ​ 116,792 ​ $ 358,538 ​ 243,685 ​ 114,853 ​

INVENTORY

INVENTORY	6 Months Ended
	Jun. 30, 2024
INVENTORY
INVENTORY	7. INVENTORY Inventory, net consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ June 30, December 31, ​ ​ 2024 ​ 2023 Raw materials ​ $ 1,135 ​ $ 1,060 Work in process ​ 1,744 ​ 2,020 Finished goods ​ 2,764 ​ 2,283 Total inventory, net ​ $ 5,643 ​ $ 5,363 ​

INTANGIBLE ASSETS

INTANGIBLE ASSETS	6 Months Ended
	Jun. 30, 2024
INTANGIBLE ASSETS
INTANGIBLE ASSETS	8. INTANGIBLE ASSETS In August 2019, the Company received FDA approval of WAKIX ® In October 2020, the Company received FDA approval for the New Drug Application (“NDA”) for WAKIX for the treatment of cataplexy in adult patients with narcolepsy. This event triggered a milestone payment of $100,000 under the provisions of the 2017 LCA which the Company capitalized as an intangible asset and paid in January of 2021. The Company determined a useful life of 9 years for such intangible asset, and, as of June 30, 2024, the remaining useful life was 5.3 years. In February 2022, the Company attained $500,000 in life-to-date aggregate net sales of WAKIX in the United States. This event triggered a final $40,000 payment under the provisions of the 2017 LCA which the Company capitalized as an intangible asset and paid in March of 2022. The Company determined a useful life of 7.6 years for such intangible asset, and, as of June 30, 2024, the remaining useful life was 5.3 years. Amortization expense was $5,961 for each of the three months ended June 30, 2024, and 2023, respectively, and $11,922 for each of the six months ended June 30, 2024, and 2023, respectively, and is recorded in general and administrative on the unaudited condensed consolidated statements of operations and comprehensive income. The Company expects the future annual amortization expense for the unamortized intangible assets to be as follows: ​ ​ ​ ​ ​ Years ending December 31, ​ ​ 2024 (excluding the six months ended June 30, 2024) ​ $ 11,923 2025 ​ 23,845 2026 ​ 23,845 2027 ​ 23,845 2028 ​ 23,845 Thereafter ​ ​ 17,883 Total ​ $ 125,186 ​ ​ ​ ​ ​ ​ ​ The gross carrying amount and net book value of the intangible asset is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ June 30, December 31, ​ ​ 2024 ​ 2023 Gross Carrying Amount ​ $ 215,000 ​ $ 215,000 Accumulated Amortization ​ (89,814) ​ (77,892) Net Book Value ​ $ 125,186 ​ $ 137,108 ​

LICENSE AGREEMENTS AND ASSET PU

LICENSE AGREEMENTS AND ASSET PURCHASE AGREEMENTS	6 Months Ended
	Jun. 30, 2024
LICENSE AGREEMENTS AND ASSET PURCHASE AGREEMENTS
LICENSE AGREEMENTS AND ASSET PURCHASE AGREEMENTS	9. LICENSE AGREEMENTS AND ASSET PURCHASE AGREEMENTS License Agreements In July 2017, Harmony entered into a License Agreement (the “2017 LCA”) with Bioprojet Société Civile de Recherche (“Bioprojet”) whereby Harmony acquired the exclusive right to commercialize the pharmaceutical compound pitolisant for the treatment, and/or prevention, of narcolepsy, obstructive sleep apnea, idiopathic hypersomnia, and Parkinson’s disease as well as any other indications unanimously agreed by the parties in the United States and its territories. A milestone payment of $50,000 was due upon acceptance by the FDA of pitolisant’s NDA, which was achieved in February 2019 and was expensed within research and development for the year ended December 31, 2019. A milestone payment of $77,000, which included a $2,000 fee that is described below, was due upon FDA approval of WAKIX (pitolisant) for treatment of EDS in adult patients with narcolepsy, which was achieved in August 2019. The $2,000 payment and $75,000 milestone payment were paid in August and November 2019, respectively. In addition, a milestone payment of $102,000, which included a $2,000 fee was due upon the FDA approval of the NDA for WAKIX for the treatment of cataplexy in adult patients with narcolepsy. The $2,000 payment was paid in October 2020 and a $100,000 milestone payment was paid in January 2021. A final $40,000 milestone payment was paid to Bioprojet in March 2022 upon WAKIX attaining $500,000 in aggregate net sales in the United States. The 2017 LCA also requires a fixed trademark royalty and a tiered royalty based on net sales, which is payable to Bioprojet on a quarterly basis. The Company incurred $30,199 and $22,542 for the three months ended June 30, 2024, and 2023, respectively, and $54,937 and $41,602 for the six months ended June 30, 2024, and 2023, respectively, for sales-based, trademark and tiered royalties recognized as cost of product sold. As of June 30, 2024, and December 31, 2023, the Company had accrued $30,199 and $40,419, respectively, for sales-based, trademark and tiered royalties. In July 2022, Harmony entered into a License and Commercialization Agreement (the “2022 LCA”) with Bioprojet whereby Harmony obtained exclusive rights to manufacture, use and commercialize one or more new products based on pitolisant in the United States and Latin America, with the potential to add additional indications and formulations upon agreement of both parties. Harmony paid an initial, non-refundable $30,000 licensing fee in October 2022 and additional payments of up to $155,000 are potentially due under the 2022 LCA upon the achievement of certain future development and sales-based milestones. In addition, there are other payments due upon achievement of development milestones for new indications and formulations as agreed upon by both parties. The 2022 LCA also requires a fixed trademark royalty and a tiered royalty based on net sales upon commercialization, which will be payable to Bioprojet on a quarterly basis. In April 2024, the Company announced that it entered into a sublicense agreement with Bioprojet for an orexin-2 receptor agonist (OX2R) (the “Licensed Compound”) to be evaluated for the treatment of narcolepsy and other potential indications (the “Sublicense”). Under the Sublicense, the Company obtained the exclusive right to develop, manufacture and commercialize the Licensed Compound in the United States and Latin American territories (the “Licensed Territories”), which are rights that Bioprojet originally licensed from Teijin Pharma, the innovator of the Licensed Compound. The Licensed Compound is currently in pre-clinical development with a Clinical Trial Application currently anticipated in mid-2025. Under the Sublicense, the Company paid Bioprojet an upfront license fee of $25,500, which the Company recognized as an IPR&D charge recorded in research and development within the unaudited condensed consolidated statements of operations and comprehensive income for the three and six months ended June 30, 2024, and will also be obligated to pay up to $127,500 upon achievement of development and regulatory milestones and up to $240,000 upon achievement of sales-based milestones, as well as royalty rates in the mid-teens on any sales of product using the Licensed Compound in the Licensed Territories. Agreement Related to Intellectual Property In August 2021, the Company entered into an asset purchase agreement with ConSynance Therapeutics, Inc. (the “APA”) to acquire HBS-102 (formerly referred to as “CSTI-100”), a potential first-in-class molecule with a novel mechanism of action. Under the terms of the APA, the Company acquired full development and commercialization rights globally, with the exception of Greater China, for $3,500. The Company accounted for the transaction as an asset acquisition as substantially all of the fair value of the assets acquired was concentrated in a single identified asset. In March 2023, the Company achieved a preclinical milestone, which triggered a $750 payment under the provisions of the APA, which the Company recognized as an IPR&D charge recorded in research and development within the unaudited condensed consolidated statement of operations and comprehensive income for the six months ended June 30, 2023. There are additional payments due under the APA upon the achievement of certain milestones including $1,000 for preclinical milestones, $19,000 for development milestones, $44,000 for regulatory milestones and $110,000 for sales milestones.

ACCRUED EXPENSES

ACCRUED EXPENSES	6 Months Ended
	Jun. 30, 2024
ACCRUED EXPENSES
ACCRUED EXPENSES	10. ACCRUED EXPENSES Accrued expenses consist of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ June 30, December 31, ​ ​ 2024 ​ 2023 Royalties due to Bioprojet ​ $ 30,199 ​ $ 40,419 Rebates and other sales deductions ​ 43,570 ​ 38,842 Interest ​ ​ 2,993 ​ ​ 3,354 Sales and marketing ​ 3,343 ​ 2,354 Research and development ​ 7,201 ​ 9,835 Professional fees, consulting, and other services ​ 2,053 ​ 2,195 Other expenses ​ 2,285 ​ 2,495 ​ ​ $ 91,644 ​ $ 99,494 ​

DEBT

DEBT	6 Months Ended
	Jun. 30, 2024
DEBT
DEBT	11. DEBT Term Loan A Credit Agreement In July 2023, the Company entered into a Credit Agreement (the “TLA Credit Agreement”) with JPMorgan Chase Bank, N.A., as “Administrative Agent”, and certain lenders. The TLA Credit Agreement provides for a five-year senior secured term loan (the “TLA Term Loan”) in an aggregate principal amount of $185,000. In September 2023, the Company entered into the First Incremental Amendment (the “First Incremental Amendment”) with the Administrative Agent and Bank of America, N.A., as incremental lender. The First Incremental Amendment provides for an incremental senior secured term loan (the “Incremental Term Loan”) in an aggregate principal amount of $15,000. The First Incremental Amendment amends the TLA Credit Agreement and provides that the Incremental Term Loan will have identical terms as the TLA Term Loan. The repayment schedule for both the TLA Term Loan and the Incremental Term Loan (together, the “Term Loans”) consists of quarterly $3,750 principal payments, which commence on December 31, 2023, increasing to quarterly $5,000 principal payments beginning on December 31, 2025, with a $115,000 payment due on the maturity date of July 26, 2028. The Term Loans bear interest at a per annum rate equal to, at the Company’s option, (i) a base rate plus a specified margin ranging from 2.50% to 3.00%, based on the Company’s senior secured net leverage ratio (as defined in the TLA Credit Agreement) or (ii) Term SOFR plus a credit spread adjustment of 0.10% plus a specified margin ranging from 3.50% to 4.00%, based on the Company’s senior secured net leverage ratio. The net cash received related to the Term Loans as a result of the transactions, less debt issuance costs of $2,997, was $197,003. The debt issuance costs related to the Term Loans will be amortized as additional interest expense over the loan term of the TLA Credit Agreement. The fair value of the Term Loans as of June 30, 2024, was $187,863. Long-term debt, net consists of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, December 31, ​ ​ 2024 ​ 2023 Principal amount ​ $ 188,750 ​ $ 196,250 Unamortized debt discount associated with debt financing costs ​ (2,328) ​ (2,684) Total debt, net ​ ​ 186,422 ​ ​ 193,566 Less current portion ​ ​ (15,000) ​ ​ (15,000) Long-term debt, net ​ $ 171,422 ​ $ 178,566 ​ Future minimum payments relating to total debt, net as of June 30, 2024, for the periods indicated below consists of the following: ​ ​ ​ ​ ​ Years ending December 31, ​ ​ ​ 2024 (excluding the six months ended June 30, 2024) ​ $ 7,500 2025 ​ 16,250 2026 ​ 20,000 2027 ​ 20,000 2028 ​ 125,000 Thereafter ​ ​ — Total ​ $ 188,750 ​ Interest expense related to the Company’s long-term debt, net, is included in interest expense within the unaudited condensed consolidated statements of operations and comprehensive income and consists of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended ​ ​ June 30, ​ June 30, ​ ​ 2024 2023 ​ 2024 2023 Interest on principal balance ​ $ 4,228 ​ $ 5,794 ​ $ 8,583 ​ $ 11,109 Amortization of deferred financing costs ​ 176 ​ 424 ​ 356 ​ 840 Total term loan interest expense ​ $ 4,404 ​ $ 6,218 ​ $ 8,939 ​ $ 11,949 ​

LEASES

LEASES	6 Months Ended
	Jun. 30, 2024
LEASES
LEASES	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 12. LEASES In June 2018, the Company entered into an operating lease for approximately fifteen thousand square feet of office space in Plymouth Meeting, PA, which expires in May 2024. The Company subsequently entered into two separate operating leases for additional office space in Plymouth Meeting, PA, which include approximately thirteen thousand square feet and seven thousand square feet of additional office space, respectively, and expire in May 2024. In March 2024, the Company amended its existing operating leases for office space in Plymouth Meeting to extend their terms through June 2025. The terms of the lease payments provide for rental payments on a monthly basis and on a graduated scale. The Company also leases a fleet of automobiles that are used by its sales representatives and are classified as operating leases. Operating lease right-of-use assets and operating lease liabilities are recognized based on the present value of the future lease payments using our incremental borrowing rate. Leases with an initial term of 12 months or less are not recorded on the balance sheet. Our leases have remaining lease terms of less than 1 year to 3 years, some of which may include the option to extend or terminate the leases. The Company recorded operating lease costs of $622 and $444 for the three months ended June 30, 2024, and 2023, respectively and $1,131 and $822 for the six months ended June 30, 2024, and 2023, respectively. As of June 30, 2024, the weighted-average remaining lease term for operating leases was 1.7 years and the weighted-average discount rate for operating leases was 7.56%. Supplemental balance sheet information related to operating leases was as follows: ​ ​ ​ ​ ​ ​ ​ Leases Classification ​ June 30, 2024 ​ December 31, 2023 Assets ​ ​ ​ ​ ​ ​ Operating lease right-of-use assets Other noncurrent assets $ 2,508 ​ $ 2,344 Liabilities ​ ​ ​ ​ ​ ​ Operating lease liability, current portion Other current liabilities $ 1,786 ​ $ 1,437 Operating lease liability, long-term Other long-term liabilities ​ 854 ​ ​ 1,082 Total operating lease liabilities ​ $ 2,640 ​ $ 2,519 ​ Supplemental cash flow information related to operating leases was as follows: ​ ​ ​ ​ ​ ​ ​ ​ June 30, 2024 ​ ​ June 30, 2023 Operating cash flows from operating leases $ 1,075 ​ $ 922 Right of use assets obtained in exchange for operating lease obligations $ 1,254 ​ $ 615 ​ Future payments under noncancelable operating leases with initial terms of one year or more as of June 30, 2024, consisted of the following: ​ ​ ​ ​ Years ending December 31, ​ ​ 2024 (excluding the six months ended June 30, 2024) ​ $ 1,047 2025 ​ 1,250 2026 ​ 495 2027 ​ 12 2028 ​ — Thereafter ​ — Total lease payments ​ ​ 2,804 Less: imputed interest ​ ​ (164) Total lease liabilities ​ $ 2,640 ​

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	6 Months Ended
	Jun. 30, 2024
COMMITMENTS AND CONTINGENCIES.
COMMITMENTS AND CONTINGENCIES	13. COMMITMENTS AND CONTINGENCIES Litigation From time to time, the Company is subject to claims and suits arising in the ordinary course of business. The Company accrues such liabilities when they are known, if they are deemed probable and can be reasonably estimated. As of June 30, 2024, there were no material claims or suits outstanding. ​

STOCKHOLDERS' EQUITY

STOCKHOLDERS' EQUITY	6 Months Ended
	Jun. 30, 2024
STOCKHOLDERS' EQUITY
STOCKHOLDERS' EQUITY	14. STOCKHOLDERS’ EQUITY Common Stock The holders of common stock are entitled to one vote for each share held on all matters submitted to a vote of the Company’s stockholders. The holders of common stock do not have any cumulative voting rights. Holders of common stock are entitled to receive any dividends declared by the Company’s board of directors out of funds legally available for that purpose, subject to any preferential dividend rights of any outstanding preferred stock. The Company’s common stock has no preemptive rights, conversion rights or other subscription rights or redemption or sinking fund provisions. Share Repurchase Program In October 2023, the Company’s Board of Directors approved a share repurchase program (the “October 2023 Repurchase Program”) providing for the repurchase of shares of common stock in an aggregate amount of up to $200,000, excluding commissions and transaction fees. The October 2023 Repurchase Program may be suspended, terminated, or modified at any time for any reason. During the three and six months ended June 30, 2024, and 2023, no shares of common stock were repurchased and cancelled by the Company. As of June 30, 2024, the remaining amount of common stock authorized for repurchases was $150,000.

STOCK INCENTIVE PLAN AND STOCK-

STOCK INCENTIVE PLAN AND STOCK-BASED COMPENSATION	6 Months Ended
	Jun. 30, 2024
STOCK INCENTIVE PLAN AND STOCK-BASED COMPENSATION
STOCK INCENTIVE PLAN AND STOCK-BASED COMPENSATION	15. STOCK INCENTIVE PLAN AND STOCK-BASED COMPENSATION 2020 Stock Incentive Plan In August 2020, the Company adopted, and its stockholders approved, the 2020 Incentive Award Plan (the “2020 Plan”), in order to facilitate the grant of cash and equity incentives to directors, employees (including the Company’s named executive officers) and consultants of the Company and its subsidiaries. The 2020 Plan provides for the grant of stock options, including incentive stock options (“ISOs”) and non-qualified stock options (“NSOs”), SARs, restricted stock, dividend equivalents, restricted stock units (“RSUs”) and other stock or cash-based awards. Stock options and stock appreciation rights under the 2020 Plan have a 10-year contractual term and vest over the vesting period specified in the applicable award agreement, at achievement of a performance requirement, or upon change of control (as defined in the applicable plan). RSUs vest over the vesting period specified in the applicable award agreement, at achievement of a performance requirement, or upon change of control (as defined in the applicable plan). As of June 30, 2024, there were 7,654,586 shares of common stock available for issuance under the 2020 Plan. The number of shares that may be issued under the 2020 Plan automatically increases on January 1 of each year in an amount equal to the lesser of (i) 4.0% of the shares of the Company’s common stock outstanding on December 31 of the preceding year or (ii) an amount determined by the Company’s board of directors. 2017 Stock Incentive Plan In August 2017, the Company adopted an equity incentive plan (the “2017 Plan”). Under the 2017 Plan, directors, officers, employees, consultants, and advisors of the Company can be paid incentive compensation measured by the value of the Company’s shares of common stock through grants of stock options, stock appreciation rights (“SARs”), or restricted stock. Following the adoption of the 2020 Plan, no further grants have been, or will be, made under the 2017 Plan. However, the 2017 Plan will continue to govern the terms and conditions of outstanding awards granted under it. Stock Options The following table summarizes stock option activity for the six months ended June 30, 2024: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ ​ ​ ​ ​ ​ Weighted- ​ ​ Average ​ ​ ​ ​ ​ ​ ​ Average ​ ​ Remaining ​ ​ Aggregate ​ ​ Number of ​ Exercise ​ ​ Contractual ​ ​ Intrinsic ​ Awards Price ​ Term ​ Value ($000's) Awards outstanding—December 31, 2023 6,316,422 ​ $ 32.47 ​ ​ 7.17 ​ ​ ​ Awards issued 1,307,396 ​ $ 30.51 ​ ​ ​ ​ ​ Awards exercised (46,996) ​ $ 8.97 ​ ​ ​ ​ ​ Awards forfeited (27,791) ​ $ 37.14 ​ ​ ​ ​ ​ Awards outstanding—June 30, 2024 7,549,031 ​ $ 32.26 ​ ​ 7.20 ​ $ 27,893 Awards exercisable—June 30, 2024 ​ 3,772,766 ​ $ 30.50 ​ ​ 6.30 ​ $ 21,050 ​ Stock Appreciation Rights The following table summarizes SARs activity for the six months ended June 30, 2024: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ ​ ​ ​ ​ ​ Weighted- ​ ​ Average ​ ​ ​ ​ ​ ​ ​ Average ​ ​ Remaining ​ ​ Aggregate ​ ​ Number of ​ Exercise ​ ​ Contractual ​ ​ Intrinsic ​ Awards Price ​ Term ​ Value ($000's) Awards outstanding—December 31, 2023 43,208 ​ $ 9.38 ​ ​ 5.32 ​ ​ ​ Awards issued — ​ $ — ​ ​ ​ ​ ​ Awards exercised — ​ $ — ​ ​ ​ ​ ​ Awards forfeited — ​ $ — ​ ​ ​ ​ Awards outstanding—June 30, 2024 43,208 ​ $ 9.38 ​ ​ 4.83 ​ $ 887 Awards exercisable—June 30, 2024 ​ 39,556 ​ $ 8.98 ​ ​ 4.72 ​ $ 827 ​ Restricted Stock Units The following table summarizes RSU activity for the six months ended June 30, 2024: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ ​ ​ ​ Average ​ ​ Number of ​ Grant Date ​ Awards Fair Value Awards outstanding—December 31, 2023 330,000 ​ $ 31.53 Awards issued 464,600 ​ $ 30.62 Awards vested (15,000) ​ $ 29.03 Awards forfeited (3,250) ​ $ 30.69 Awards outstanding—June 30, 2024 776,350 ​ $ 31.03 ​ Value of Stock Options and SARs The Company values options and SARs using the Black-Scholes option-pricing model. The Company lacks sufficient historical company-specific volatility information. Therefore, the Company estimates expected stock volatility based on historical volatility of peer companies and expects to continue to do so until such time as it has adequate historical data regarding the volatility of its own traded stock price. For options with service-based vesting conditions, the expected term of the Company’s stock options has been determined utilizing the “simplified” method for awards that qualify as “plain-vanilla” options. For SARs, the expected term is based upon the weighting of certain future events. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect at the time of grant of the award for the time periods approximately equal to the expected term of the award. An expected dividend yield of 0% is based on the fact that the Company has never paid cash dividends and does not expect to do so in the foreseeable future. The assumptions used to value the awards are summarized in the following table. ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ June 30, December 31, ​ ​ 2024 2023 ​ Dividend yield 0.00 % 0.00 % Expected volatility 69.84 - 72.98 % 74.87 - 80.78 % Risk-free interest rate 4.06 - 4.65 % 3.42 - 4.62 % Lack of marketability discount 0.00 % 0.00 % Expected term (years) 2.04 - 6.11 2.26 - 10.77 ​ ​ Value of RSUs The fair value of RSUs is equal to the value of the Company’s common stock on the grant date. The weighted average per share fair value of awards issued under the 2017 Plan and 2020 Plan was $21.24 and $20.64 on June 30, 2024, and December 31, 2023, respectively. Stock-Based Compensation Expense Stock-based compensation expense for the three and six months ended June 30, 2024, and 2023, was recorded in the unaudited condensed consolidated statements of operations and comprehensive income in the following line items: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, ​ Six Months Ended June 30, ​ 2024 2023 2024 2023 Research and development expense ​ $ 1,683 ​ $ 956 ​ $ 3,054 ​ $ 1,932 Sales and marketing expense ​ 2,100 ​ 1,146 ​ 4,094 ​ 2,219 General and administrative expense ​ 7,180 ​ 5,691 ​ 14,249 ​ 10,203 ​ ​ $ 10,963 ​ $ 7,793 ​ $ 21,397 ​ $ 14,354 ​ ​ Stock-based compensation expense related to options and RSUs issued under the 2017 Plan and 2020 Plan is included in stockholder’s equity, and a liability for SARs is included in other non-current liabilities, in the Company’s unaudited condensed consolidated balance sheet. As of June 30, 2024, the total unrecognized stock-based compensation expense was $68,926 and $19,749 for stock options and RSUs, respectively. This amount will be recognized in the Company’s consolidated statement of operations over a weighted average period of 2.6 years. ​ Employee Stock Purchase Plan The 2020 Employee Stock Purchase Plan (“ESPP”) was adopted by the Company’s Board of Directors on April 30, 2021. The ESPP permits eligible employees to purchase shares of the Company’s common stock at a 15% discount from the lesser of the fair market value per share of the Company’s common stock on the first day of the offering period or the fair market value of the Company’s common stock on the purchase date. Funds are collected from employees through after-tax payroll deductions. The total number of shares reserved for issuance under the ESPP was initially 629,805, which automatically increases on January 1 of each year in an amount equal to the lesser of (i) 1.0% of the shares of the Company’s common stock outstanding on December 31 of the preceding year or (ii) an amount determined by the Company’s board of directors. It is intended that the ESPP meet the requirements for an “employee stock purchase plan” under Section 423 of the Internal Revenue Code. There were 10,707 and 14,043 shares issued under the ESPP for each of the three and six months ended June 30, 2024, and 2023, respectively. The discount on the ESPP was $78 and $103 for the three months ended June 30, 2024, and 2023, respectively, and $158 and $208 for the six months ended June 30, 2024, and 2023, respectively, and is recorded within stock-based compensation expense.

EARNINGS PER SHARE

EARNINGS PER SHARE	6 Months Ended
	Jun. 30, 2024
EARNINGS PER SHARE
EARNINGS PER SHARE	16. EARNINGS PER SHARE Basic earnings per share is calculated by dividing net income by the weighted average number of shares of common stock outstanding. Diluted net income per share of common is computed under the treasury stock method by using the weighted average number of shares of common stock outstanding, plus, for periods with net income, the potential dilutive effects of stock options, stock appreciation rights and restricted stock units. The following table sets forth the computation of basic and diluted net income per share: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, ​ Six Months Ended June 30, ​ ​ 2024 2023 2024 2023 Numerator ​ ​ ​ ​ ​ Net income ​ $ 11,591 ​ $ 34,300 ​ $ 49,925 ​ $ 63,785 Denominator ​ ​ ​ ​ Net income per share of common stock - basic ​ $ 0.20 ​ $ 0.57 ​ $ 0.88 ​ $ 1.07 Net income per share of common stock- diluted ​ $ 0.20 ​ $ 0.56 ​ $ 0.87 ​ $ 1.05 Weighted average number of shares of common stock - basic ​ 56,802,357 ​ 59,974,123 ​ 56,786,873 ​ 59,853,808 Weighted average number of shares of common stock - diluted ​ 57,541,696 ​ 60,743,953 ​ 57,571,570 ​ 60,997,410 ​ Securities outstanding that were included in the computation above, utilizing the treasury stock method are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, ​ Six Months Ended June 30, ​ ​ 2024 2023 2024 2023 Stock options, SARs, and RSUs to purchase common stock ​ ​ 739,339 ​ ​ 769,830 ​ ​ 784,697 ​ ​ 1,143,602 ​ Potential shares of common stock issuable that were excluded from the computation of diluted weighted-average shares outstanding excluded from the numerator, are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, ​ Six Months Ended June 30, ​ ​ 2024 2023 2024 2023 Stock options, SARs, and RSUs to purchase common stock ​ 7,629,250 ​ 5,520,235 ​ ​ 7,583,892 ​ 5,146,464 ​

INCOME TAXES

INCOME TAXES	6 Months Ended
	Jun. 30, 2024
INCOME TAXES
INCOME TAXES	17. INCOME TAXES A reconciliation between the statutory federal income tax rate and the Company’s effective income tax rate for the three and six months ended June 30, 2024, and 2023 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, ​ Six Months Ended June 30, ​ 2024 2023 ​ ​ 2024 2023 ​ Federal income tax rate 21.0 % 21.0 % ​ 21.0 % 21.0 % Stock-based compensation (0.7) ​ (0.5) ​ ​ (0.2) ​ (1.5) ​ State taxes 11.2 ​ 4.0 ​ ​ 7.4 ​ 5.1 ​ Credits (2.6) ​ (2.9) ​ ​ (1.6) ​ (2.9) ​ Nondeductible IPR&D 16.5 ​ — ​ ​ 4.9 ​ — ​ Valuation allowance 0.6 ​ — ​ ​ 0.3 ​ — ​ Other 0.6 ​ 0.6 ​ ​ 0.3 ​ 0.4 ​ Total 46.6 % 22.2 % ​ 32.1 % 22.1 % ​

RELATED-PARTY TRANSACTIONS

RELATED-PARTY TRANSACTIONS	6 Months Ended
	Jun. 30, 2024
RELATED-PARTY TRANSACTIONS
RELATED-PARTY TRANSACTIONS	18. RELATED-PARTY TRANSACTIONS The Company was party to a management agreement for professional services provided by a related party, Paragon Biosciences, LLC (“Paragon”). Paragon is an entity that shares common ownership with the Company. In addition, the Chairman of the Company’s board of directors is the Founder, Chairman and CEO of Paragon. The Company is also party to a right of use agreement with Paragon whereby it has access to and the right to use certain office space leased by Paragon in Chicago, IL. The Company incurred $72 and $74 for the three months ended June 30, 2024, and 2023, respectively, and incurred $145 and $145 for the six months ended June 30, 2024, and 2023, respectively, in expenses to Paragon, which are included in general and administrative in the unaudited condensed consolidated statements of operations and comprehensive loss. As of June 30, 2024, and December 31, 2023, there were no amounts due to or due from related parties included in the unaudited condensed consolidated balance sheets.

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ 11,591	$ 34,300	$ 49,925	$ 63,785

Insider Trading Arrangements

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

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	6 Months Ended
	Jun. 30, 2024
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Basis of Presentation	Basis of Presentation The unaudited condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”) and include all adjustments necessary for the fair presentation of the Company’s financial position for the periods presented. All intercompany accounts and transactions have been eliminated in consolidation. The unaudited condensed consolidated balance sheet as of June 30, 2024, the unaudited condensed consolidated statements of cash flows for the six months ended June 30, 2024, and 2023, and the unaudited condensed consolidated statements of operations and comprehensive income and the unaudited condensed consolidated statements of shareholders’ equity for the three and six months ended June 30, 2024, and 2023, are unaudited. The balance sheet as of December 31, 2023, was derived from audited financial statements as of and for the year ended December 31, 2023. The unaudited interim condensed consolidated financial statements have been prepared on the same basis as the audited annual financial statements as of and for the year ended December 31, 2023, and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair presentation of the Company’s financial position as of June 30, 2024, and the results of its operations and its cash flows for the three and six months ended June 30, 2024, and 2023. The unaudited condensed consolidated results of operations are not necessarily indicative of the results that may occur for the full fiscal year. Certain information and disclosures normally included in the financial statements prepared in accordance with GAAP have been condensed or omitted under the SEC’s rules and regulations. These unaudited condensed consolidated financial statements should be read in conjunction with the audited financial statements and accompanying notes thereto contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023.
Reclassifications	Reclassifications Certain prior period amounts within the unaudited condensed consolidated statements of operations and comprehensive income have been reclassified to conform to current period presentation. In particular, interest expense and interest income were previously classified together as interest expense, net and are now separately classified as interest expense and interest income, respectively. The reclassification of these items had no impact on net income, earnings per share or accumulated deficit in current or prior periods.
Significant Risks and Uncertainties	Significant Risks and Uncertainties The Company’s operations are subject to a number of factors that can affect its operating results and financial condition. Such factors include, but are not limited to, clinical trial results of the Company’s product candidates; the Company’s ability to obtain regulatory approval to market its products; competition from products manufactured and sold or being developed by other companies; the price of, and demand for, the Company’s products, if approved; the Company’s ability to negotiate favorable licensing or other manufacturing and marketing agreements for its product candidates. The Company currently has one commercially approved product, WAKIX, and there can be no assurance that the Company’s research and development efforts will result in successfully commercialized products in addition to WAKIX. Developing and commercializing a product requires significant time and capital and is subject to regulatory review and approval as well as competition from other biotechnology and pharmaceutical companies. The Company operates in an environment of rapid change and is dependent upon the continued services of its employees and consultants and obtaining and protecting intellectual property.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts and disclosures in the unaudited condensed consolidated financial statements, including the notes thereto, and elsewhere in this report. Actual results may differ significantly from estimates, which include rebates due pursuant to commercial and government contracts, accrued research and development expenses, stock-based compensation expense and income taxes.
Operating Segments	Operating Segments The Company holds all its tangible assets, conducts its operations, and generates its revenue in the United States. Operating segments are defined as components of an entity for which separate financial information is available and that is regularly reviewed by the Chief Operating Decision Makers in deciding how to allocate resources to an individual segment and in assessing performance. The Company has determined it operates in a single operating segment and has one reportable segment.
Fair Value of Financial Instruments	​ Fair Value of Financial Instruments The Company’s unaudited condensed consolidated financial statements include cash, cash equivalents, restricted cash, accounts payable, and accrued liabilities, all of which are short term in nature and, accordingly, approximate fair value. It is the Company’s policy to measure non-financial assets and liabilities at fair value on a nonrecurring basis. These non-financial assets and liabilities are not measured at fair value on an ongoing basis but are subject to fair value adjustments in certain circumstances (such as evidence of impairment), which, if material, are disclosed in the accompanying footnotes. The Company measures certain assets and liabilities at fair value based on the fair value hierarchy that prioritizes inputs to valuation techniques used to measure fair value into three levels based on the source of inputs as follows: Level 1—Valuations based on unadjusted quoted prices in active markets for identical assets or liabilities. Level 2—Valuations based on observable inputs and quoted prices in active markets for similar assets and liabilities. Level 3—Valuations based on unobservable inputs and models that are supported by little or no market activity. Money market funds are classified as Level 1 fair value instruments. Investments in available-for-sale debt securities are classified as Level 2 and carried at fair value, which we estimate utilizing a third-party pricing service. The pricing service utilizes industry standard valuation models whereby all significant inputs, including benchmark yields, reported trades, broker/dealer quotes, issuer spreads, bids, offers, or other market-related data, are observable. We validate valuations obtained from third-party services by obtaining market values from other pricing sources. The Company did not classify any assets or liabilities as Level 3 as of June 30, 2024, or December 31, 2023.
Cash, Cash Equivalents and Restricted Cash	Cash, Cash Equivalents and Restricted Cash Cash and cash equivalents and restricted cash consist of cash and, if applicable, highly liquid investments with an original maturity of three months or less when purchased, including investments in Money Market Funds and debt securities that approximate fair value. The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the balance sheet and the statements of cash flows. ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ June 30, December 31, ​ ​ 2024 ​ 2023 Cash and cash equivalents ​ $ 317,296 ​ $ 311,660 Restricted cash ​ 270 ​ 270 Total cash, cash equivalents, and restricted cash shown in the statements of cash flows ​ $ 317,566 ​ $ 311,930 ​ Restricted cash includes amounts required to be held as a security deposit in the form of letters of credit for the Company’s credit card program and the fleet program.
Investments	Investments The Company’s investments consist of debt securities that are classified as available-for-sale. Short-term and long-term investments are carried at fair value and unrealized gains and losses are recorded as a component of accumulated comprehensive income in stockholders’ equity. Interest income earned on cash and investment balances, accretion of the discount on investments in debt securities, amortization of premiums and realized gains and losses, if any, are recorded in interest income on the unaudited condensed consolidated statement of operations and comprehensive income. Realized gains and losses that result from the sale of investments are determined on a specific identification basis. At each reporting period, the Company reviews any unrealized losses position to determine if the decline in the fair value of the underlying investments is a result of credit losses or other factors. If the assessment indicates that a credit loss exists, any impairment is recognized as an allowance for credit losses in our consolidated statement of operations.
Concentrations of Risk	Concentrations of Risk Substantially all of the Company’s cash and money market funds are held in five financial institutions. Due to their size, the Company believes these financial institutions represent minimal credit risk. Deposits may exceed the amount of insurance provided on such deposits by the Federal Deposit Insurance Corporation for U.S. institutions. The Company has not experienced any losses on its deposits of cash and cash equivalents. The Company believes that it is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held. The Company is subject to credit risk from its trade receivables related to its product sales. The Company extends credit to specialty pharmaceutical distribution companies within the United States. Customer creditworthiness is monitored, and collateral is not required. Historically, the Company has not experienced credit losses on its accounts receivable. The Company monitors its exposure within accounts receivable and would record a reserve against uncollectible accounts receivable if necessary. As of June 30, 2024, three customers accounted for 100% of gross accounts receivable; Caremark LLC (“CVS Caremark”), which accounted for 41% of gross accounts receivable; Accredo Health Group, Inc. (“Accredo”), which accounted for 35% of gross accounts receivable; and PANTHERx Specialty Pharmacy LLC (“Pantherx”), which accounted for 24% of gross accounts receivable. As of December 31, 2023, three customers accounted for 100% of gross accounts receivable; Accredo, which accounted for 39% of gross accounts receivable, CVS Caremark, which accounted for 32% of gross accounts receivable; and Pantherx, which accounted for 29% of gross accounts receivable. For the six months ended June 30, 2024, three customers accounted for 100% of gross product revenue; CVS Caremark accounted for 40% of gross product revenue; Accredo accounted for 33% of gross product revenue; and Pantherx accounted for 27% of gross product revenue. For the six months ended June 30, 2023, three customers accounted for 100% of gross product revenue; CVS Caremark accounted for 35% of gross product revenue; Pantherx accounted for 33% of gross product revenue; and Accredo accounted for 32% of gross product revenue. The Company depends on a single supplier for its product and a single supplier for its active pharmaceutical ingredient.
Share Repurchases	Share Repurchases The Company accounts for share repurchases as constructive retirements, whereby it reduces common stock and additional paid-in capital by the amount of the original issuance, with any excess purchase price recorded as a reduction to retained earnings. Under this method, issued and outstanding shares of common stock are reduced by the amount of shares of common stock repurchased, and no treasury stock is recognized on the condensed consolidated financial statements.
Business Combinations	​ ​ Business Combinations Business combinations and asset acquisitions are accounted for in accordance with FASB ASC 805 Business Combinations. Refer to Note 4, Acquisitions
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements In November 2023, the FASB issued Accounting Standards Update (“ASU”) No. 2023-07, Improvements to Reportable Segment Disclosures ​ In December 2023, the FASB issued Accounting Standards Update (“ASU”) No 2023-09, “Income Taxes (Topic 740): Improvements to Income Tax Disclosures”

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	6 Months Ended
	Jun. 30, 2024
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Schedule of reconciliation of cash, cash equivalents, and restricted cash	The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the balance sheet and the statements of cash flows. ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ June 30, December 31, ​ ​ 2024 ​ 2023 Cash and cash equivalents ​ $ 317,296 ​ $ 311,660 Restricted cash ​ 270 ​ 270 Total cash, cash equivalents, and restricted cash shown in the statements of cash flows ​ $ 317,566 ​ $ 311,930

ACQUISITIONS (Tables)

ACQUISITIONS (Tables)	6 Months Ended
	Jun. 30, 2024
ACQUISITIONS
Schedule of purchase consideration and allocation of purchase consideration	​ ​ ​ ​ ​ Cash consideration paid to selling shareholders and to settle restricted stock units ("RSUs") ​ $ 32,686 Transaction costs ​ ​ 450 Total purchase consideration ​ $ 33,136 ​ ​ ​ ​ ​ ​ Assets acquired ​ ​ ​ Acquired in-process research and development ​ $ 17,095 Deferred tax asset ​ ​ 18,268 Other assets ​ ​ 590 Total assets acquired ​ $ 35,953 Total liabilities assumed ​ $ 2,817 ​ ​ ​ ​ Net assets acquired ​ $ 33,136 ​

INVESTMENTS (Tables)

INVESTMENTS (Tables)	6 Months Ended
	Jun. 30, 2024
INVESTMENTS
Schedule of carrying value and amortized cost of available-for-sale debt securities	​ The carrying value and amortized cost of the Company’s available-for-sale debt securities, summarized by type of security, consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, 2024 ​ ​ Amortized ​ Unrealized ​ Unrealized ​ ​ Fair ​ ​ Cost ​ Gains ​ Losses ​ ​ Value Short-term: ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial paper $ 16,175 ​ 1 ​ (5) ​ $ 16,171 Corporate debt securities ​ 13,443 ​ 4 ​ (4) ​ ​ 13,443 Total short-term investments $ 29,618 ​ 5 ​ (9) ​ $ 29,614 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Long-term: ​ ​ ​ ​ ​ ​ ​ ​ ​ Corporate debt securities ​ 59,793 ​ 37 ​ (87) ​ ​ 59,743 U.S. government securities ​ 27,615 ​ — ​ (180) ​ ​ 27,435 Total long-term investments $ 87,408 ​ 37 ​ (267) ​ $ 87,178 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2023 ​ ​ Amortized ​ Unrealized ​ Unrealized ​ ​ Fair ​ ​ Cost ​ Gains ​ Losses ​ ​ Value Short-term: ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial paper $ 23,832 ​ 36 ​ (3) ​ $ 23,865 Corporate debt securities ​ 15,968 ​ 28 ​ — ​ ​ 15,996 U.S. government securities ​ 1,940 ​ — ​ (1) ​ ​ 1,939 Total short-term investments $ 41,740 ​ 64 ​ (4) ​ $ 41,800 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Long-term: ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial paper $ 744 ​ — ​ — ​ $ 744 Corporate debt securities ​ 42,688 ​ 81 ​ (28) ​ ​ 42,741 U.S. government securities ​ 28,795 ​ 7 ​ (118) ​ ​ 28,684 Total long-term investments $ 72,227 ​ 88 ​ (146) ​ $ 72,169

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	6 Months Ended
	Jun. 30, 2024
FAIR VALUE MEASUREMENTS
Schedule of assets measured at fair value	The Company’s assets measured at fair value consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, 2024 ​ December 31, 2023 ​ ​ Total ​ Level 1 ​ Level 2 ​ ​ Total ​ Level 1 ​ Level 2 Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash equivalents $ 270,989 ​ 270,989 ​ — ​ $ 244,569 ​ 243,685 ​ 884 Commercial paper ​ 16,171 ​ — ​ 16,171 ​ ​ 24,609 ​ — ​ 24,609 Corporate debt securities ​ 73,186 ​ — ​ 73,186 ​ ​ 58,737 ​ — ​ 58,737 U.S. government securities ​ 27,435 ​ — ​ 27,435 ​ ​ 30,623 ​ — ​ 30,623 Total $ 387,781 ​ 270,989 ​ 116,792 ​ $ 358,538 ​ 243,685 ​ 114,853 ​

INVENTORY (Tables)

INVENTORY (Tables)	6 Months Ended
	Jun. 30, 2024
INVENTORY
Schedule of inventory net	Inventory, net consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ June 30, December 31, ​ ​ 2024 ​ 2023 Raw materials ​ $ 1,135 ​ $ 1,060 Work in process ​ 1,744 ​ 2,020 Finished goods ​ 2,764 ​ 2,283 Total inventory, net ​ $ 5,643 ​ $ 5,363 ​

INTANGIBLE ASSETS (Tables)

INTANGIBLE ASSETS (Tables)	6 Months Ended
	Jun. 30, 2024
INTANGIBLE ASSETS
Schedule of future annual amortization expense for unamortized intangible assets	The Company expects the future annual amortization expense for the unamortized intangible assets to be as follows: ​ ​ ​ ​ ​ Years ending December 31, ​ ​ 2024 (excluding the six months ended June 30, 2024) ​ $ 11,923 2025 ​ 23,845 2026 ​ 23,845 2027 ​ 23,845 2028 ​ 23,845 Thereafter ​ ​ 17,883 Total ​ $ 125,186
Schedule of gross carrying amount and net book value of intangible assets	​ ​ ​ ​ ​ The gross carrying amount and net book value of the intangible asset is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ June 30, December 31, ​ ​ 2024 ​ 2023 Gross Carrying Amount ​ $ 215,000 ​ $ 215,000 Accumulated Amortization ​ (89,814) ​ (77,892) Net Book Value ​ $ 125,186 ​ $ 137,108

ACCRUED EXPENSES (Tables)

ACCRUED EXPENSES (Tables)	6 Months Ended
	Jun. 30, 2024
ACCRUED EXPENSES
Schedule of accrued expenses	Accrued expenses consist of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ June 30, December 31, ​ ​ 2024 ​ 2023 Royalties due to Bioprojet ​ $ 30,199 ​ $ 40,419 Rebates and other sales deductions ​ 43,570 ​ 38,842 Interest ​ ​ 2,993 ​ ​ 3,354 Sales and marketing ​ 3,343 ​ 2,354 Research and development ​ 7,201 ​ 9,835 Professional fees, consulting, and other services ​ 2,053 ​ 2,195 Other expenses ​ 2,285 ​ 2,495 ​ ​ $ 91,644 ​ $ 99,494 ​

DEBT (Tables)

DEBT (Tables)	6 Months Ended
	Jun. 30, 2024
DEBT
Schedule of long-term debt, net	Long-term debt, net consists of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ June 30, December 31, ​ ​ 2024 ​ 2023 Principal amount ​ $ 188,750 ​ $ 196,250 Unamortized debt discount associated with debt financing costs ​ (2,328) ​ (2,684) Total debt, net ​ ​ 186,422 ​ ​ 193,566 Less current portion ​ ​ (15,000) ​ ​ (15,000) Long-term debt, net ​ $ 171,422 ​ $ 178,566
Schedule of future minimum payments relating to total debt	Future minimum payments relating to total debt, net as of June 30, 2024, for the periods indicated below consists of the following: ​ ​ ​ ​ ​ Years ending December 31, ​ ​ ​ 2024 (excluding the six months ended June 30, 2024) ​ $ 7,500 2025 ​ 16,250 2026 ​ 20,000 2027 ​ 20,000 2028 ​ 125,000 Thereafter ​ ​ — Total ​ $ 188,750
Schedule of interest expense related to the company's long-term debt	Interest expense related to the Company’s long-term debt, net, is included in interest expense within the unaudited condensed consolidated statements of operations and comprehensive income and consists of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended ​ ​ June 30, ​ June 30, ​ ​ 2024 2023 ​ 2024 2023 Interest on principal balance ​ $ 4,228 ​ $ 5,794 ​ $ 8,583 ​ $ 11,109 Amortization of deferred financing costs ​ 176 ​ 424 ​ 356 ​ 840 Total term loan interest expense ​ $ 4,404 ​ $ 6,218 ​ $ 8,939 ​ $ 11,949 ​

LEASES (Tables)

LEASES (Tables)	6 Months Ended
	Jun. 30, 2024
LEASES
Schedule of supplemental balance sheet and cash flow information related to operating leases	Supplemental balance sheet information related to operating leases was as follows: ​ ​ ​ ​ ​ ​ ​ Leases Classification ​ June 30, 2024 ​ December 31, 2023 Assets ​ ​ ​ ​ ​ ​ Operating lease right-of-use assets Other noncurrent assets $ 2,508 ​ $ 2,344 Liabilities ​ ​ ​ ​ ​ ​ Operating lease liability, current portion Other current liabilities $ 1,786 ​ $ 1,437 Operating lease liability, long-term Other long-term liabilities ​ 854 ​ ​ 1,082 Total operating lease liabilities ​ $ 2,640 ​ $ 2,519 ​ Supplemental cash flow information related to operating leases was as follows: ​ ​ ​ ​ ​ ​ ​ ​ June 30, 2024 ​ ​ June 30, 2023 Operating cash flows from operating leases $ 1,075 ​ $ 922 Right of use assets obtained in exchange for operating lease obligations $ 1,254 ​ $ 615
Schedule of future payments under noncancelable operating leases	Future payments under noncancelable operating leases with initial terms of one year or more as of June 30, 2024, consisted of the following: ​ ​ ​ ​ Years ending December 31, ​ ​ 2024 (excluding the six months ended June 30, 2024) ​ $ 1,047 2025 ​ 1,250 2026 ​ 495 2027 ​ 12 2028 ​ — Thereafter ​ — Total lease payments ​ ​ 2,804 Less: imputed interest ​ ​ (164) Total lease liabilities ​ $ 2,640 ​

STOCK INCENTIVE PLAN AND STOC_2

STOCK INCENTIVE PLAN AND STOCK-BASED COMPENSATION (Tables)	6 Months Ended
	Jun. 30, 2024
STOCK INCENTIVE PLAN AND STOCK-BASED COMPENSATION
Summary of changes in stock options granted	The following table summarizes stock option activity for the six months ended June 30, 2024: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ ​ ​ ​ ​ ​ Weighted- ​ ​ Average ​ ​ ​ ​ ​ ​ ​ Average ​ ​ Remaining ​ ​ Aggregate ​ ​ Number of ​ Exercise ​ ​ Contractual ​ ​ Intrinsic ​ Awards Price ​ Term ​ Value ($000's) Awards outstanding—December 31, 2023 6,316,422 ​ $ 32.47 ​ ​ 7.17 ​ ​ ​ Awards issued 1,307,396 ​ $ 30.51 ​ ​ ​ ​ ​ Awards exercised (46,996) ​ $ 8.97 ​ ​ ​ ​ ​ Awards forfeited (27,791) ​ $ 37.14 ​ ​ ​ ​ ​ Awards outstanding—June 30, 2024 7,549,031 ​ $ 32.26 ​ ​ 7.20 ​ $ 27,893 Awards exercisable—June 30, 2024 ​ 3,772,766 ​ $ 30.50 ​ ​ 6.30 ​ $ 21,050
Summary of changes in SARs granted	The following table summarizes SARs activity for the six months ended June 30, 2024: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ ​ ​ ​ ​ ​ Weighted- ​ ​ Average ​ ​ ​ ​ ​ ​ ​ Average ​ ​ Remaining ​ ​ Aggregate ​ ​ Number of ​ Exercise ​ ​ Contractual ​ ​ Intrinsic ​ Awards Price ​ Term ​ Value ($000's) Awards outstanding—December 31, 2023 43,208 ​ $ 9.38 ​ ​ 5.32 ​ ​ ​ Awards issued — ​ $ — ​ ​ ​ ​ ​ Awards exercised — ​ $ — ​ ​ ​ ​ ​ Awards forfeited — ​ $ — ​ ​ ​ ​ Awards outstanding—June 30, 2024 43,208 ​ $ 9.38 ​ ​ 4.83 ​ $ 887 Awards exercisable—June 30, 2024 ​ 39,556 ​ $ 8.98 ​ ​ 4.72 ​ $ 827
Summary of changes in RSUs granted	The following table summarizes RSU activity for the six months ended June 30, 2024: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ ​ ​ ​ Average ​ ​ Number of ​ Grant Date ​ Awards Fair Value Awards outstanding—December 31, 2023 330,000 ​ $ 31.53 Awards issued 464,600 ​ $ 30.62 Awards vested (15,000) ​ $ 29.03 Awards forfeited (3,250) ​ $ 30.69 Awards outstanding—June 30, 2024 776,350 ​ $ 31.03
Summary of assumptions used to value awards	​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ June 30, December 31, ​ ​ 2024 2023 ​ Dividend yield 0.00 % 0.00 % Expected volatility 69.84 - 72.98 % 74.87 - 80.78 % Risk-free interest rate 4.06 - 4.65 % 3.42 - 4.62 % Lack of marketability discount 0.00 % 0.00 % Expected term (years) 2.04 - 6.11 2.26 - 10.77 ​
Summary of stock-based compensation expense	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, ​ Six Months Ended June 30, ​ 2024 2023 2024 2023 Research and development expense ​ $ 1,683 ​ $ 956 ​ $ 3,054 ​ $ 1,932 Sales and marketing expense ​ 2,100 ​ 1,146 ​ 4,094 ​ 2,219 General and administrative expense ​ 7,180 ​ 5,691 ​ 14,249 ​ 10,203 ​ ​ $ 10,963 ​ $ 7,793 ​ $ 21,397 ​ $ 14,354

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	6 Months Ended
	Jun. 30, 2024
EARNINGS PER SHARE
Summary of computation of basic and diluted net income (loss) per share	The following table sets forth the computation of basic and diluted net income per share: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, ​ Six Months Ended June 30, ​ ​ 2024 2023 2024 2023 Numerator ​ ​ ​ ​ ​ Net income ​ $ 11,591 ​ $ 34,300 ​ $ 49,925 ​ $ 63,785 Denominator ​ ​ ​ ​ Net income per share of common stock - basic ​ $ 0.20 ​ $ 0.57 ​ $ 0.88 ​ $ 1.07 Net income per share of common stock- diluted ​ $ 0.20 ​ $ 0.56 ​ $ 0.87 ​ $ 1.05 Weighted average number of shares of common stock - basic ​ 56,802,357 ​ 59,974,123 ​ 56,786,873 ​ 59,853,808 Weighted average number of shares of common stock - diluted ​ 57,541,696 ​ 60,743,953 ​ 57,571,570 ​ 60,997,410 ​ Securities outstanding that were included in the computation above, utilizing the treasury stock method are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, ​ Six Months Ended June 30, ​ ​ 2024 2023 2024 2023 Stock options, SARs, and RSUs to purchase common stock ​ ​ 739,339 ​ ​ 769,830 ​ ​ 784,697 ​ ​ 1,143,602
Summary of antidilutive securities excluded from computation of earnings per share	Potential shares of common stock issuable that were excluded from the computation of diluted weighted-average shares outstanding excluded from the numerator, are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, ​ Six Months Ended June 30, ​ ​ 2024 2023 2024 2023 Stock options, SARs, and RSUs to purchase common stock ​ 7,629,250 ​ 5,520,235 ​ ​ 7,583,892 ​ 5,146,464 ​

INCOME TAXES (Tables)

INCOME TAXES (Tables)	6 Months Ended
	Jun. 30, 2024
INCOME TAXES
Schedule of reconciliation between statutory federal income tax rate and the Company's effective income tax rate	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended June 30, ​ Six Months Ended June 30, ​ 2024 2023 ​ ​ 2024 2023 ​ Federal income tax rate 21.0 % 21.0 % ​ 21.0 % 21.0 % Stock-based compensation (0.7) ​ (0.5) ​ ​ (0.2) ​ (1.5) ​ State taxes 11.2 ​ 4.0 ​ ​ 7.4 ​ 5.1 ​ Credits (2.6) ​ (2.9) ​ ​ (1.6) ​ (2.9) ​ Nondeductible IPR&D 16.5 ​ — ​ ​ 4.9 ​ — ​ Valuation allowance 0.6 ​ — ​ ​ 0.3 ​ — ​ Other 0.6 ​ 0.6 ​ ​ 0.3 ​ 0.4 ​ Total 46.6 % 22.2 % ​ 32.1 % 22.1 % ​

LIQUIDITY AND CAPITAL RESOURC_2

LIQUIDITY AND CAPITAL RESOURCES (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
LIQUIDITY AND CAPITAL RESOURCES
Accumulated deficit	$ 93,352	$ 143,277
Cash, cash equivalents and investments	$ 434,088

SUMMARY OF SIGNIFICANT ACCOUN_4

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Reconciliation of Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023	Jun. 30, 2023	Dec. 31, 2022
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Cash and cash equivalents	$ 317,296	$ 311,660
Restricted cash	270	270
Total cash, cash equivalents, and restricted cash shown in the statements of cash flows	$ 317,566	$ 311,930	$ 317,665	$ 244,534

SUMMARY OF SIGNIFICANT ACCOUN_5

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Additional Information (Details)	6 Months Ended		12 Months Ended
	Jun. 30, 2024 segment product Institution customer	Jun. 30, 2023 customer	Dec. 31, 2023 customer
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Number of approved commercial products | product	1
Number of operating segments | segment	1
Number of reportable segments | segment	1
Number Of financial institutions | Institution	5
Three Customers | Accounts Receivable | Customer Concentration Risk
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Number of customers | customer	3		3
Concentration risk percentage	100%		100%
Three Customers | Product Revenues | Customer Concentration Risk
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Number of customers | customer	3	3
Concentration risk percentage	100%	100%
Accredo Health Group, Inc | Accounts Receivable | Customer Concentration Risk
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Concentration risk percentage	35%		39%
Accredo Health Group, Inc | Product Revenues | Customer Concentration Risk
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Concentration risk percentage	33%	32%
Caremark LLC | Accounts Receivable | Customer Concentration Risk
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Concentration risk percentage	41%		32%
Caremark LLC | Product Revenues | Customer Concentration Risk
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Concentration risk percentage	40%	35%
PANTHERx Specialty Pharmacy LLC | Accounts Receivable | Customer Concentration Risk
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Concentration risk percentage	24%		29%
PANTHERx Specialty Pharmacy LLC | Product Revenues | Customer Concentration Risk
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Line Items]
Concentration risk percentage	27%	33%

ACQUISITIONS (Details)

ACQUISITIONS (Details) $ / shares in Units, $ in Thousands		1 Months Ended	3 Months Ended	6 Months Ended
	Apr. 30, 2024 USD ($)	Oct. 31, 2023 USD ($) Right $ / shares	Jun. 30, 2024 USD ($)	Jun. 30, 2024 USD ($)
ACQUISITIONS
Transaction costs		$ 2,645
Acquired in-process research and development expense				$ 42,595
Zynerba Acquisition
ACQUISITIONS
Cash consideration per common stock | $ / shares		$ 1.1059
Aggregate consideration		$ 60,000
Number of contingent value right per common stock | Right		1
Contingent consideration per common stock | $ / shares		$ 2.5444
Epygenix Acquisition
ACQUISITIONS
Aggregate consideration	$ 32,686
Transaction costs	450
Asset acquisition, upfront consideration paid	35,000
Amount of fee payable upon achieving development and regulatory milestones	130,000
Amount of fees payable upon achieving sale-based milestones	$ 515,000
Acquired in-process research and development expense			$ 17,095	$ 17,095

ACQUISITIONS - Purchase Conside

ACQUISITIONS - Purchase Consideration (Details) - USD ($) $ in Thousands		1 Months Ended
	Apr. 30, 2024	Oct. 31, 2023
ACQUISITIONS
Transaction costs		$ 2,645
Epygenix Acquisition
ACQUISITIONS
Cash consideration paid to selling shareholders and to settle restricted stock units ("RSUs")	$ 32,686
Transaction costs	450
Total purchase consideration	$ 33,136

ACQUISITIONS - Net Assets Acqui

ACQUISITIONS - Net Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Apr. 30, 2024	Dec. 31, 2023
Assets acquired
Deferred tax asset	$ 180,186		$ 144,162
TOTAL ASSETS	858,383		811,448
Total liabilities assumed	$ 319,800		$ 344,456
Epygenix Acquisition
Assets acquired
Acquired in-process research and development		$ 17,095
Deferred tax asset		18,268
Other assets		590
TOTAL ASSETS		35,953
Total liabilities assumed		2,817
Net assets acquired		$ 33,136

INVESTMENTS - Carrying Value an

INVESTMENTS - Carrying Value and Amortized Cost of Available-For-Sale Debt Securities (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2024	Dec. 31, 2023
Minimum
Investment securities
Non current investment maturity term	1 year
Maximum
Investment securities
Non current investment maturity term	2 years
Short-term
Investment securities
Amortized Cost	$ 29,618	$ 41,740
Unrealized Gains	5	64
Unrealized Losses	(9)	(4)
Fair Value	29,614	41,800
Short-term commercial paper
Investment securities
Amortized Cost	16,175	23,832
Unrealized Gains	1	36
Unrealized Losses	(5)	(3)
Fair Value	16,171	23,865
Short-term corporate debt securities
Investment securities
Amortized Cost	13,443	15,968
Unrealized Gains	4	28
Unrealized Losses	(4)
Fair Value	13,443	15,996
Short-term U.S. government securities
Investment securities
Amortized Cost		1,940
Unrealized Losses		(1)
Fair Value		1,939
Long-term
Investment securities
Amortized Cost	87,408	72,227
Unrealized Gains	37	88
Unrealized Losses	(267)	(146)
Fair Value	87,178	72,169
Long-term commercial paper
Investment securities
Amortized Cost		744
Fair Value		744
Long-term corporate debt securities
Investment securities
Amortized Cost	59,793	42,688
Unrealized Gains	37	81
Unrealized Losses	(87)	(28)
Fair Value	59,743	42,741
Long-term U.S. government securities
Investment securities
Amortized Cost	27,615	28,795
Unrealized Gains		7
Unrealized Losses	(180)	(118)
Fair Value	$ 27,435	$ 28,684

FAIR VALUE MEASUREMENTS - Asset

FAIR VALUE MEASUREMENTS - Assets Measured at Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Assets
Assets	$ 387,781	$ 358,538
Cash equivalents
Assets
Assets	270,989	244,569
Commercial paper
Assets
Assets	16,171	24,609
Corporate debt securities
Assets
Assets	73,186	58,737
U.S. government securities
Assets
Assets	27,435	30,623
Level 1
Assets
Assets	270,989	243,685
Level 1 | Cash equivalents
Assets
Assets	270,989	243,685
Level 2
Assets
Assets	116,792	114,853
Level 2 | Cash equivalents
Assets
Assets		884
Level 2 | Commercial paper
Assets
Assets	16,171	24,609
Level 2 | Corporate debt securities
Assets
Assets	73,186	58,737
Level 2 | U.S. government securities
Assets
Assets	$ 27,435	$ 30,623

INVENTORY (Details)

INVENTORY (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
INVENTORY
Raw materials	$ 1,135	$ 1,060
Work in process	1,744	2,020
Finished goods	2,764	2,283
Total inventory, net	$ 5,643	$ 5,363

INTANGIBLE ASSETS - Additional

INTANGIBLE ASSETS - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended				3 Months Ended		6 Months Ended
	Mar. 31, 2022	Feb. 28, 2022	Oct. 31, 2020	Aug. 31, 2019	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Intangible Assets
Net product revenue					$ 172,814	$ 134,216	$ 327,429	$ 253,342
Amortization expense					$ 5,961	$ 5,961	$ 11,922	$ 11,922
WAKIX
Intangible Assets
Useful life of intangible asset	7 years 7 months 6 days
Remaining useful life					5 years 3 months 18 days		5 years 3 months 18 days
Final payment paid	$ 40,000
WAKIX | United States
Intangible Assets
Net product revenue		$ 500,000
WAKIX | Daytime Sleepiness
Intangible Assets
License agreement milestone payments paid				$ 75,000
Useful life of intangible asset				10 years
Remaining useful life					5 years 3 months 18 days		5 years 3 months 18 days
NDA for WAKIX. | Cataplexy
Intangible Assets
License agreement milestone payments paid			$ 100,000
Useful life of intangible asset			9 years
Remaining useful life					5 years 3 months 18 days		5 years 3 months 18 days

INTANGIBLE ASSETS - Schedule of

INTANGIBLE ASSETS - Schedule of Future Annual Amortization Expense for Unamortized Intangible Assets (Details) $ in Thousands	Jun. 30, 2024 USD ($)
Future annual amortization expense
2024 (excluding the six months ended June 30, 2024)	$ 11,923
2025	23,845
2026	23,845
2027	23,845
2028	23,845
Thereafter	17,883
Total	$ 125,186

INTANGIBLE ASSETS - Schedule _2

INTANGIBLE ASSETS - Schedule of Gross Carrying Amount and Net Book Value of Intangible Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
INTANGIBLE ASSETS
Gross Carrying Amount	$ 215,000	$ 215,000
Accumulated Amortization	(89,814)	(77,892)
Net Book Value	$ 125,186	$ 137,108

LICENSE AGREEMENTS AND ASSET _2

LICENSE AGREEMENTS AND ASSET PURCHASE AGREEMENTS (Details) - USD ($) $ in Thousands

1 Months Ended

3 Months Ended

6 Months Ended

Apr. 30, 2024

Mar. 31, 2023

Jul. 31, 2022

Mar. 31, 2022

Aug. 31, 2021

Jan. 31, 2021

Oct. 31, 2020

Nov. 30, 2019

Aug. 31, 2019

Jun. 30, 2024

Jun. 30, 2023

Jun. 30, 2024

Jun. 30, 2023

Dec. 31, 2023

Feb. 28, 2019

License Agreements and Asset Purchase Agreements

Cost of product sold

$ 32,144

$ 25,008

$ 59,628

$ 45,788

Accrued Sales Based Trademark and Royalties

30,199

30,199

$ 40,419

All Countries Excluding Greater China | HBS-102 | Asset Purchase Agreement with ConSynance Therapeutics

License Agreements and Asset Purchase Agreements

Consideration transferred

$ 3,500

Payment for intellectual property upon preclinical milestones

1,000

Payment for intellectual property upon developmental milestones

19,000

Payment for intellectual property upon regulatory milestones

44,000

Payment for intellectual property upon sales milestones

$ 110,000

All Countries Excluding Greater China | HBS-102 | Asset Purchase Agreement with ConSynance Therapeutics | Research and development expense

License Agreements and Asset Purchase Agreements

Payment related to achievement of preclinical milestone.

$ 750,000

Bioprojet

License Agreements and Asset Purchase Agreements

Licensing agreement milestone fees

$ 2,000

License agreement milestone payments paid

$ 75,000

2,000

License agreement, additional milestone payment due

102,000

Bioprojet | Upon Acceptance by FDA of Pitolisant's

License Agreements and Asset Purchase Agreements

License agreement, milestone payment due

$ 50,000

License agreement, upfront non-refundable licensing fees paid

$ 30,000

License agreement, maximum additional milestone payment due

$ 155,000

Bioprojet | Upon FDA Approval of WAKIX

License Agreements and Asset Purchase Agreements

License agreement, milestone payment due

77,000

Licensing agreement milestone fees

$ 2,000

License agreement milestone payments paid

$ 100,000

$ 2,000

Bioprojet | Sales-based, trademark and tiered royalties

License Agreements and Asset Purchase Agreements

Cost of product sold

30,199

$ 22,542

54,937

$ 41,602

Accrued Sales Based Trademark and Royalties

$ 30,199

30,199

$ 40,419

Bioprojet | Orexin-2 receptor agonist (OX2R)

License Agreements and Asset Purchase Agreements

Payment of upfront license fee

$ 25,500

$ 25,500

Amount of fee payable upon achieving development and regulatory milestones

127,500

Amount of fees payable upon achieving sale-based milestones

$ 240,000

Bioprojet | United States

License Agreements and Asset Purchase Agreements

Amount of Aggregate Net Sales Attaining

$ 500,000

Bioprojet | Attaining $500,000 Aggregate Net Sales | United States | Upon FDA Approval of WAKIX

License Agreements and Asset Purchase Agreements

Final payment paid

$ 40,000

ACCRUED EXPENSES (Details)

ACCRUED EXPENSES (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
ACCRUED EXPENSES
Royalties due to Bioprojet	$ 30,199	$ 40,419
Rebates and other sales deductions	43,570	38,842
Interest	2,993	3,354
Sales and marketing	3,343	2,354
Research and development	7,201	9,835
Professional fees, consulting, and other services	2,053	2,195
Other expenses	2,285	2,495
Accrued liabilities	$ 91,644	$ 99,494

DEBT - Additional Information (

DEBT - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended	6 Months Ended
	Jul. 31, 2023	Jun. 30, 2024	Sep. 30, 2023
Term Loans
DEBT
Debt issuance costs		$ 2,997
Net cash received		197,003
Fair value of loan		187,863
Term Loans | Repayment Of Debt Commencing On December 31 2023
DEBT
Periodic payment principal		3,750
Term Loans | Repayment Of Debt Beginning On December 31 2025
DEBT
Periodic payment principal		5,000
Term Loans | Repayment of Debt Due on Maturity Date of July 26, 2028
DEBT
Periodic payment principal		$ 115,000
Term Loans | Base rate | Minimum
DEBT
Basis spread on variable rate		2.50%
Term Loans | Base rate | Maximum
DEBT
Basis spread on variable rate		3%
Term Loans | SOFR
DEBT
Credit spread adjustment rate		0.10%
Term Loans | SOFR | Minimum
DEBT
Basis spread on variable rate		3.50%
Term Loans | SOFR | Maximum
DEBT
Basis spread on variable rate		4%
TLA Term Loan
DEBT
Term of loan	5 years
Aggregate principal amount	$ 185,000
Incremental Term Loan
DEBT
Aggregate principal amount			$ 15,000

DEBT - Balances of Long-term De

DEBT - Balances of Long-term Debt, Net (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
DEBT
Principal amount	$ 188,750	$ 196,250
Unamortized debt discount associated with debt financing costs	(2,328)	(2,684)
Total debt, net	186,422	193,566
Less current portion	(15,000)	(15,000)
Long-term debt, net	$ 171,422	$ 178,566

DEBT - Future Minimum Payments

DEBT - Future Minimum Payments (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Future minimum payments
2024 (excluding the six months ended June 30, 2024)	$ 7,500
2025	16,250
2026	20,000
2027	20,000
2028	125,000
Total	$ 188,750	$ 196,250

DEBT - Interest Expense (Detail

DEBT - Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
DEBT
Interest on principal balance	$ 4,228	$ 5,794	$ 8,583	$ 11,109
Amortization of deferred financing costs	176	424	356	840
Total term loan interest expense	$ 4,404	$ 6,218	$ 8,939	$ 11,949

LEASES (Details)

LEASES (Details) ft² in Thousands, $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Jun. 30, 2018 ft²	Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($)
LEASES
Operating lease square feet of office space	15
Additional office space leased one	13
Additional office space leased two	7
Lessee, Operating Lease, Existence of Option to Extend [true false]				true
Lessee, Operating Lease, Existence of Option to Terminate [true false]				true
Operating lease costs | $		$ 622	$ 444	$ 1,131	$ 822
Weighted average remaining lease term		1 year 8 months 12 days		1 year 8 months 12 days
Weighted-average discount rate for operating leases		7.56%		7.56%
Minimum
LEASES
Lease terms		1 year		1 year
Maximum
LEASES
Lease terms		3 years		3 years

LEASES - Supplemental Balance S

LEASES - Supplemental Balance Sheet Information (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Assets
Operating lease right-of-use assets	$ 2,508	$ 2,344
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other Assets Noncurrent	Other Assets Noncurrent
Liabilities
Operating lease liability, current portion	$ 1,786	$ 1,437
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other Liabilities Current	Other Liabilities Current
Operating lease liability, long-term	$ 854	$ 1,082
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other Liabilities Noncurrent	Other Liabilities Noncurrent
Total operating lease liabilities	$ 2,640	$ 2,519

LEASES - Supplemental Cash Flow

LEASES - Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
LEASES
Operating cash flows from operating leases	$ 1,075	$ 922
Right of use assets obtained in exchange for operating lease obligations	$ 1,254	$ 615

LEASES - Future Payments (Detai

LEASES - Future Payments (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Years ending December 31,
2024 (excluding the six months ended June 30, 2024)	$ 1,047
2025	1,250
2026	495
2027	12
Total lease payments	2,804
Less: imputed interest	(164)
Total lease liabilities	$ 2,640	$ 2,519

STOCKHOLDERS' EQUITY (Details)

STOCKHOLDERS' EQUITY (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2024 shares	Mar. 31, 2023 shares	Jun. 30, 2024 USD ($) Vote shares	Jun. 30, 2023 shares	Oct. 31, 2023 USD ($)
Equity, Class of Treasury Stock [Line Items]
Number of votes for each common stock | Vote			1
October 2023 Repurchase Program
Equity, Class of Treasury Stock [Line Items]
Repurchase of shares of common stock approved					$ 200,000
Shares of common stock repurchased and retired | shares	0	0	0	0
Remaining authorized repurchase amount			$ 150,000

STOCK INCENTIVE PLAN AND STOC_3

STOCK INCENTIVE PLAN AND STOCK-BASED COMPENSATION - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		6 Months Ended		12 Months Ended
	Apr. 30, 2021	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Stock Incentive Plan and Stock-based Compensation
Weighted average period				2 years 7 months 6 days
Employee Stock Option
Stock Incentive Plan and Stock-based Compensation
Unrecognized stock-based compensation expense		$ 68,926		$ 68,926
Restricted Stock Units
Stock Incentive Plan and Stock-based Compensation
Weighted average per share fair value of awards issued (in USD per share)				$ 30.62
Unrecognized stock-based compensation expense		$ 19,749		$ 19,749
2020 Plan
Stock Incentive Plan and Stock-based Compensation
Stock options contractual term				10 years
Total number of shares available for issuance		7,654,586		7,654,586
Percentage of increment of common stock outstanding				4%
2017 and 2020 Plans | Restricted Stock Units
Stock Incentive Plan and Stock-based Compensation
Weighted average per share fair value of awards issued (in USD per share)				$ 21.24		$ 20.64
Employee Stock Purchase Plan
Stock Incentive Plan and Stock-based Compensation
Total number of shares available for issuance	629,805
Percentage of increment of common stock outstanding	1%
ESPP permits eligible employees to purchase shares of common stock at discount	15%
Shares issued under the ESPP		10,707	14,043	10,707	14,043
Amount of discount on ESSP		$ 78	$ 103	$ 158	$ 208

STOCK INCENTIVE PLAN AND STOC_4

STOCK INCENTIVE PLAN AND STOCK-BASED COMPENSATION - Summary of Changes in Stock Options Granted (Details) $ / shares in Units, $ in Thousands		6 Months Ended
	Dec. 31, 2023 $ / shares shares	Jun. 30, 2024 USD ($) $ / shares shares
STOCK INCENTIVE PLAN AND STOCK-BASED COMPENSATION
Number of Awards, Awards outstanding, Beginning balance | shares		6,316,422
Number of Awards, Awards issued | shares		1,307,396
Number of Awards, Awards exercised | shares		(46,996)
Number of Awards, Awards forfeited | shares		(27,791)
Number of Awards, Awards outstanding, Ending balance | shares	6,316,422	7,549,031
Number of Awards, Awards exercisable | shares		3,772,766
Weighted-Average Exercise Price, Awards outstanding, Beginning balance | $ / shares		$ 32.47
Weighted-Average Exercise Price, Awards issued | $ / shares		30.51
Weighted-Average Exercise Price, Awards exercised | $ / shares		8.97
Weighted-Average Exercise Price, Awards forfeited | $ / shares		37.14
Weighted-Average Exercise Price, Awards outstanding, Ending balance | $ / shares	$ 32.47	32.26
Weighted-Average Exercise Price, Awards exercisable | $ / shares		$ 30.50
Weighted-Average Remaining Contractual Term	7 years 2 months 1 day	7 years 2 months 12 days
Weighted-Average Remaining Contractual Term, Awards exercisable		6 years 3 months 18 days
Aggregate Intrinsic Value, Awards outstanding, Ending balance | $		$ 27,893
Aggregate Intrinsic Value, Awards exercisable | $		$ 21,050

STOCK INCENTIVE PLAN AND STOC_5

STOCK INCENTIVE PLAN AND STOCK-BASED COMPENSATION - Summary of Changes in SARs Granted (Details) - USD ($) $ / shares in Units, $ in Thousands		6 Months Ended
	Dec. 31, 2023	Jun. 30, 2024
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-Average Remaining Contractual Term	5 years 3 months 25 days	4 years 9 months 29 days
Weighted-Average Remaining Contractual Term, Awards exercisable		4 years 8 months 19 days
Stock Appreciation Rights (SARs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Awards, Awards outstanding, Beginning balance		43,208
Number of Awards, Awards issued		0
Number of Awards, Awards outstanding, Ending balance	43,208	43,208
Number of Awards, Awards exercisable		39,556
Weighted-Average Exercise Price, Awards outstanding, Beginning balance		$ 9.38
Weighted-Average Exercise Price, Awards issued		0
Weighted-Average Exercise Price, Awards outstanding, Ending balance	$ 9.38	9.38
Weighted-Average Exercise Price, Awards exercisable		$ 8.98
Aggregate Intrinsic Value, Awards outstanding, Ending balance		$ 887
Aggregate Intrinsic Value, Awards exercisable		$ 827

STOCK INCENTIVE PLAN AND STOC_6

STOCK INCENTIVE PLAN AND STOCK-BASED COMPENSATION - Summary of Changes in RSUs Granted (Details) - Restricted Stock Units	6 Months Ended
	Jun. 30, 2024 $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Awards, Awards outstanding, Beginning balance | shares	330,000
Number of Awards, Awards issued | shares	464,600
Number of Awards, Awards vested | shares	(15,000)
Number of Awards, Awards forfeited | shares	(3,250)
Number of Awards, Awards outstanding, Ending balance | shares	776,350
Weighted-Average Grant Date Fair Value, Awards outstanding, Beginning balance | $ / shares	$ 31.53
Weighted-Average Grant Date Fair Value, Awards issued | $ / shares	30.62
Weighted-Average Grant Date Fair Value, Awards vested | $ / shares	29.03
Weighted-Average Grant Date Fair Value, Awards forfeited | $ / shares	30.69
Weighted-Average Grant Date Fair Value, Awards outstanding, Ending balance | $ / shares	$ 31.03

STOCK INCENTIVE PLAN AND STOC_7

STOCK INCENTIVE PLAN AND STOCK-BASED COMPENSATION - Summary of Assumptions Used to Value Awards (Details)	6 Months Ended	12 Months Ended
	Jun. 30, 2024	Dec. 31, 2023
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Dividend yield	0%	0%
Expected volatility, minimum	69.84%	74.87%
Expected volatility, maximum	72.98%	80.78%
Risk-free interest rate, minimum	4.06%	3.42%
Risk-free interest rate, maximum	4.65%	4.62%
Lack of marketability discount	0%	0%
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (years)	2 years 14 days	2 years 3 months 3 days
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (years)	6 years 1 month 9 days	10 years 9 months 7 days

STOCK INCENTIVE PLAN AND STOC_8

STOCK INCENTIVE PLAN AND STOCK-BASED COMPENSATION - Summary of Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 10,963	$ 7,793	$ 21,397	$ 14,354
Research and development expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	1,683	956	3,054	1,932
Sales and marketing expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	2,100	1,146	4,094	2,219
General and administrative expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 7,180	$ 5,691	$ 14,249	$ 10,203

EARNINGS PER SHARE - Summary of

EARNINGS PER SHARE - Summary of Computation of Basic and Diluted Net Income (Loss) per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Numerator
Net Income (Loss)	$ 11,591	$ 34,300	$ 49,925	$ 63,785
Denominator
Net income per share of common stock - basic	$ 0.20	$ 0.57	$ 0.88	$ 1.07
Net income per share of common stock - diluted	$ 0.20	$ 0.56	$ 0.87	$ 1.05
Weighted average number of shares of common stock - basic	56,802,357	59,974,123	56,786,873	59,853,808
Weighted average number of shares of common stock - diluted	57,541,696	60,743,953	57,571,570	60,997,410

EARNINGS PER SHARE - Summary _2

EARNINGS PER SHARE - Summary of Securities Outstanding Included in Computation above, Utilizing Treasury Stock Method (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
EARNINGS PER SHARE
Securities outstanding included in the computation - Stock options, SARs, and RSUs to purchase common stock	739,339	769,830	784,697	1,143,602

EARNINGS PER SHARE - Summary _3

EARNINGS PER SHARE - Summary of Antidilutive Securities Excluded from Computation of Earnings Per Share (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
EARNINGS PER SHARE
Potential shares of common stock issuable excluded from computation - Stock options, SARs, and RSUs to purchase common stock	7,629,250	5,520,235	7,583,892	5,146,464

INCOME TAXES - Schedule of Diff

INCOME TAXES - Schedule of Difference Between Statutory Federal Income Tax Rate (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
INCOME TAXES
Federal income tax rate	21%	21%	21%	21%
Stock-based compensation	(0.70%)	(0.50%)	(0.20%)	(1.50%)
State taxes	11.20%	4%	7.40%	5.10%
Credits	(2.60%)	(2.90%)	(1.60%)	(2.90%)
Nondeductible IPR&D	16.50%		4.90%
Valuation allowance	0.60%		0.30%
Other	0.60%	0.60%	0.30%	0.40%
Total	46.60%	22.20%	32.10%	22.10%

RELATED-PARTY TRANSACTIONS (Det

RELATED-PARTY TRANSACTIONS (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Related-party Transactions
General and administrative	$ 27,224	$ 22,809	$ 52,900	$ 44,871
Amounts due to related parties	$ 0		$ 0		$ 0
Other Liability, Related Party, Type [Extensible Enumeration]	Related party		Related party		Related party
Amounts due from related parties	$ 0		$ 0		$ 0
Other Receivable, after Allowance for Credit Loss, Related Party, Type [Extensible Enumeration]	Related party		Related party		Related party
Related party
Related-party Transactions
General and administrative	$ 72	$ 74	$ 145	$ 145