Madrigal Pharmaceuticals (MDGL) 10-K 28 Feb 24 2023 FY Annual report Financial data

Cover Page

Cover Page - USD ($)	12 Months Ended
	Dec. 31, 2023	Feb. 16, 2024	Jun. 30, 2023
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Current Fiscal Year End Date	--12-31
Document Period End Date	Dec. 31, 2023
Document Transition Report	false
Entity File Number	001-33277
Entity Registrant Name	MADRIGAL PHARMACEUTICALS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	04-3508648
Entity Address, Address Line One	Four Tower Bridge
Entity Address, Address Line Two	200 Barr Harbor Drive, Suite 200
Entity Address, City or Town	West Conshohocken
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	19428
City Area Code	267
Local Phone Number	824-2827
Title of 12(b) Security	Common Stock, $0.0001 Par Value Per Share
Trading Symbol	MDGL
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
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
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Public Float			$ 3,158,123,661
Entity Common Stock, Shares Outstanding		19,897,425
Documents Incorporated by Reference	Certain information required by Part III, Items 10-14 of this Form 10-K is incorporated by reference to the registrant’s definitive Proxy Statement for the 2024 Annual Meeting of Stockholders to be filed with the Securities and Exchange Commission pursuant to Regulation 14A not later than 120 days after the end of the fiscal year covered by this Form 10-K, provided that if such Proxy Statement is not filed within such period, such information will be included in an amendment to this Form 10-K to be filed within such 120-day period.
Auditor Firm ID	238
Auditor Name	PricewaterhouseCoopers LLP
Auditor Location	Philadelphia, Pennsylvania
Entity Central Index Key	0001157601
Document Fiscal Year Focus	2023
Amendment Flag	false
Document Fiscal Period Focus	FY

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 99,915,000	$ 331,549,000
Marketable securities	534,216,000	27,225,000
Prepaid expenses and other current assets	3,150,000	2,595,000
Total current assets	637,281,000	361,369,000
Property and equipment, net	1,553,000	601,000
Right-of-use asset	1,713,000	602,000
Total assets	640,547,000	362,572,000
Current liabilities:
Accounts payable	28,041,000	23,831,000
Accrued expenses	89,980,000	91,461,000
Lease liability	527,000	602,000
Total current liabilities	118,548,000	115,894,000
Long term liabilities:
Loan payable, net of discount	115,480,000	49,289,000
Lease liability	1,186,000	0
Total long term liabilities	116,666,000	49,289,000
Total liabilities	235,214,000	165,183,000
Stockholders’ equity:
Preferred stock, par value $0.0001 per share authorized: 5,000,000 shares at December 31, 2023 and December 31, 2022; 2,369,797 and 2,369,797 shares issued and outstanding at December 31, 2023 and December 31, 2022, respectively	0	0
Common stock, par value $0.0001 per share authorized: 200,000,000 at December 31, 2023 and December 31, 2022; 19,875,427 and 18,102,523 shares issued and outstanding at December 31, 2023 and December 31, 2022, respectively	2,000	2,000
Additional paid-in-capital	1,741,153,000	1,160,079,000
Accumulated other comprehensive income (loss)	468,000	(32,000)
Accumulated deficit	(1,336,290,000)	(962,660,000)
Total stockholders’ equity	405,333,000	197,389,000
Total liabilities and stockholders’ equity	$ 640,547,000	$ 362,572,000

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, authorized (in shares)	5,000,000	5,000,000
Preferred stock, issued (in shares)	2,369,797	2,369,797
Preferred stock, outstanding (in shares)	2,369,797	2,369,797
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, authorized (in shares)	200,000,000	200,000,000
Common stock, issued (shares)	19,875,427	18,102,523
Common stock, outstanding (shares)	19,875,427	18,102,523

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenues:
Total revenues	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0
Operating expenses:
Research and development	70,640,000	70,951,000	68,605,000	62,154,000	70,742,000	68,271,000	58,499,000	47,929,000	272,350,000	245,441,000	205,164,000
General and administrative	46,536,000	27,583,000	17,845,000	16,182,000	14,557,000	12,141,000	11,774,000	9,658,000	108,146,000	48,130,000	37,318,000
Total operating expenses	117,176,000	98,534,000	86,450,000	78,336,000	85,299,000	80,412,000	70,273,000	57,587,000	380,496,000	293,571,000	242,482,000
Loss from operations	(117,176,000)	(98,534,000)	(86,450,000)	(78,336,000)	(85,299,000)	(80,412,000)	(70,273,000)	(57,587,000)	(380,496,000)	(293,571,000)	(242,482,000)
Interest income	8,953,000	3,298,000	3,551,000	3,776,000	1,076,000	717,000	323,000	69,000	19,578,000	2,185,000	363,000
Interest expense	(3,971,000)	(3,504,000)	(2,901,000)	(2,336,000)	(1,682,000)	(1,502,000)	(780,000)	0	(12,712,000)	(3,964,000)	0
Other income	0	0	0	0	0	0	0	0	0	0	273,000
Net loss	$ (112,194,000)	$ (98,740,000)	$ (85,800,000)	$ (76,896,000)	$ (85,905,000)	$ (81,197,000)	$ (70,730,000)	$ (57,518,000)	$ (373,630,000)	$ (295,350,000)	$ (241,846,000)
Net loss per common share:
Basic net loss per common share (in dollars per share)	$ (5.68)	$ (5.34)	$ (4.69)	$ (4.23)	$ (4.98)	$ (4.75)	$ (4.14)	$ (3.36)	$ (19.99)	$ (17.23)	$ (14.63)
Diluted net loss per common share (in dollars per share)	$ (5.68)	$ (5.34)	$ (4.69)	$ (4.23)	$ (4.98)	$ (4.75)	$ (4.14)	$ (3.36)	$ (19.99)	$ (17.23)	$ (14.63)
Basic weighted average number of common shares outstanding (in shares)	19,760,842	18,476,414	18,310,952	18,187,924	17,237,517	17,103,395	17,103,395	17,103,395	18,687,774	17,137,201	16,535,188
Diluted weighted average number of common shares outstanding (in shares)	19,760,842	18,476,414	18,310,952	18,187,924	17,237,517	17,103,395	17,103,395	17,103,395	18,687,774	17,137,201	16,535,188

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Comprehensive Income [Abstract]
Net Loss	$ (373,630)	$ (295,350)	$ (241,846)
Other comprehensive income (loss):
Unrealized gain (loss) on available-for-sale securities	500	48	(127)
Comprehensive loss	$ (373,130)	$ (295,302)	$ (241,973)

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Nonrelated Party	Related Party	Preferred stock	Preferred stock Nonrelated Party	Common stock	Common stock Nonrelated Party	Common stock Related Party	Additional paid-in Capital	Additional paid-in Capital Nonrelated Party	Additional paid-in Capital Related Party	Accumulated other comprehensive income (loss)	Accumulated deficit
Beginning balance (in shares) at Dec. 31, 2020				1,969,797		15,508,146
Beginning balance at Dec. 31, 2020	$ 239,970			$ 0		$ 2			$ 665,385			$ 47	$ (425,464)
Increase (Decrease) in Stockholders' Equity
Issuance of common and preferred shares in equity offerings, excluding to related parties, net of transaction costs (in shares)							1,584,169
Issuance of common shares in equity offering, excluding to related parties, net of transaction costs		$ 170,207								$ 170,207
Sale of common shares to related parties and exercise of common stock options, net of transaction costs ( in shares)								11,080
Sale of common shares to related parties and exercise of common stock options, net of transaction costs			$ 1,030								$ 1,030
Compensation expense related to stock options for services	26,873								26,873
Unrealized gain (loss) on available-for-sale securities	(127)											(127)
Net Loss	(241,846)												(241,846)
Ending balance (in shares) at Dec. 31, 2021				1,969,797		17,103,395
Ending balance at Dec. 31, 2021	196,107			$ 0		$ 2			863,495			(80)	(667,310)
Increase (Decrease) in Stockholders' Equity
Issuance of common and preferred shares in equity offerings, excluding to related parties, net of transaction costs (in shares)					400,000		783,344
Issuance of common shares in equity offering, excluding to related parties, net of transaction costs		255,382								255,382
Sale of common shares to related parties and exercise of common stock options, net of transaction costs ( in shares)								215,784
Sale of common shares to related parties and exercise of common stock options, net of transaction costs			8,955								8,955
Compensation expense related to stock options for services	31,625								31,625
Unrealized gain (loss) on available-for-sale securities	48											48
Hercules warrant	622								622
Net Loss	$ (295,350)												(295,350)
Ending balance (in shares) at Dec. 31, 2022	18,102,523			2,369,797		18,102,523
Ending balance at Dec. 31, 2022	$ 197,389			$ 0		$ 2			1,160,079			(32)	(962,660)
Increase (Decrease) in Stockholders' Equity
Issuance of common and preferred shares in equity offerings, excluding to related parties, net of transaction costs (in shares)							1,346,199	426,705
Issuance of common shares in equity offering, excluding to related parties, net of transaction costs		$ 260,187	$ 270,292							$ 260,187	$ 270,292
Sale of common shares to related parties and exercise of common stock options, net of transaction costs ( in shares)	460,385
Compensation expense related to stock options for services	$ 49,735								49,735
Unrealized gain (loss) on available-for-sale securities	500											500
Hercules warrant	860								860
Net Loss	$ (373,630)												(373,630)
Ending balance (in shares) at Dec. 31, 2023	19,875,427			2,369,797		19,875,427
Ending balance at Dec. 31, 2023	$ 405,333			$ 0		$ 2			$ 1,741,153			$ 468	$ (1,336,290)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities:
Net loss	$ (373,630)	$ (295,350)	$ (241,846)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	49,735	31,625	26,873
Depreciation and amortization expense	527	467	405
Amortization of debt issuance costs and discount	2,414	797	0
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(555)	(1,257)	(325)
Accounts payable	4,210	2,451	20,363
Accrued expense	(1,481)	36,413	9,826
Accrued interest, net of interest received on maturity of investments	(5,450)	(3)	787
Net cash used in operating activities	(324,230)	(224,857)	(183,917)
Cash flows from investing activities:
Purchases of marketable securities	(834,439)	(143,478)	(394,120)
Sales and maturities of marketable securities	333,398	350,381	389,274
Purchases of property and equipment, net of disposals	(1,479)	(217)	(209)
Net cash provided by (used in) investing activities	(502,520)	206,686	(5,055)
Cash flows from financing activities:
Proceeds from issuance of loan payable	65,000	50,000	0
Payment of debt issuance costs	(363)	(886)	0
Net cash provided by financing activities	595,116	313,451	171,237
Net increase (decrease) in cash and cash equivalents	(231,634)	295,280	(17,735)
Cash and cash equivalents at beginning of period	331,549	36,269	54,004
Cash and cash equivalents at end of period	99,915	331,549	36,269
Supplemental disclosure of cash flow information:
Obtaining a right-of-use asset in exchange for a lease liability	1,628	583	376
Related Party
Cash flows from financing activities:
Proceeds from issuance or sale of equity	270,292	8,955	1,030
Nonrelated Party
Cash flows from financing activities:
Proceeds from issuance or sale of equity	$ 260,187	$ 255,382	$ 170,207

Organization, Business and Basi

Organization, Business and Basis of Presentation	12 Months Ended
	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization, Business and Basis of Presentation	Organization, Business and Basis of Presentation Organization and Business Madrigal Pharmaceuticals, Inc. (the “Company” or “Madrigal”) is a clinical-stage biopharmaceutical company pursuing novel therapeutics for nonalcoholic steatohepatitis (“NASH”), a liver disease with high unmet medical need. The Company's lead candidate, resmetirom, a once-daily, oral, liver-directed thyroid hormone receptor-β (“THR-β”) agonist designed to target key underlying causes of NASH, is in registration status following review acceptance by the U.S. Food and Drug Administration (the “FDA”) for its New Drug Application (“NDA”) in September 2023. Basis of Presentation

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Principle of Consolidation The consolidated financial statements include the financial statements of the Company and its wholly owned subsidiaries. All significant intercompany balances and transactions have been eliminated in consolidation. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect certain reported amounts of assets and liabilities, and the reported amounts of revenues and expenses during the reporting periods. The Company bases its estimates on historical experience and various other assumptions that management believes to be reasonable under the circumstances. Changes in estimates are recorded in the period in which they become known. Actual results could differ from those estimates. Cash and Cash Equivalents The Company considers all highly liquid investments with original maturities of three months or less at the date of purchase to be cash equivalents. The Company maintains its cash in bank accounts, the balance of which, at times, exceeds Federal Deposit Insurance Corporation insured limits. The primary objective of the Company’s investment activities is to preserve its capital for the purpose of funding operations and the Company does not enter into investments for trading or speculative purposes. The Company’s cash is deposited in highly rated financial institutions in the United States. The Company invests in money market funds and high-grade, commercial paper and corporate bonds, which management believes are subject to minimal credit and market risk. Marketable Securities Marketable securities consist of investments in high-grade corporate obligations, and government and government agency obligations that are classified as available-for-sale. Since these securities are available to fund current operations they are classified as current assets on the consolidated balance sheets. The Company adjusts the cost of available-for-sale debt securities for amortization of premiums and accretion of discounts to maturity. The Company includes such amortization and accretion as a component of interest income, net. Realized gains and losses and declines in value, if any, that the Company judges to be the result of impairment or as a result of recognizing an allowance for credit losses on available-for-sale securities are reported as a component of interest income. To determine whether an impairment exists, the Company considers whether it intends to sell the debt security and, if the Company does not intend to sell the debt security, it considers available evidence to assess whether it is more likely than not that it will be required to sell the security before the recovery of its amortized cost basis. During the years ended December 31, 2023, 2022 and 2021, the Company determined it did not have any securities that were other-than-temporarily impaired. Marketable securities are stated at fair value, including accrued interest, with their unrealized gains and losses included as a component of accumulated other comprehensive income or loss, which is a separate component of stockholders’ equity. The fair value of these securities is based on quoted prices and observable inputs on a recurring basis. Realized gains and losses are determined on the specific identification method. During the years ended December 31, 2023, 2022 and 2021, the Company did not have any realized gains or losses on marketable securities. Fair Value of Financial Instruments The carrying amounts of the Company’s financial instruments, which include cash equivalents, and marketable securities, approximate their fair values. The fair value of the Company’s financial instruments reflects the amounts that would be received upon sale of an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The fair value hierarchy has the following three levels: Level 1—quoted prices in active markets for identical assets and liabilities. Level 2—observable inputs other than Level 1 inputs. Examples of Level 2 inputs include quoted prices in active markets for similar assets or liabilities and quoted prices for identical assets or liabilities in markets that are not active. Level 3—unobservable inputs that reflect the Company’s own assumptions about the assumptions market participants would use in pricing the asset or liability. Financial assets and liabilities are classified in their entirety within the fair value hierarchy based on the lowest level of input that is significant to the fair value measurement. The Company measures the fair value of its marketable securities by taking into consideration valuations obtained from third-party pricing sources. The pricing services utilize industry standard valuation models, including both income and market-based approaches, for which all significant inputs are observable, either directly or indirectly, to estimate fair value. These inputs include reported trades of and broker-dealer quotes on the same or similar securities, issuer credit spreads, benchmark securities and other observable inputs. As of December 31, 2023 and 2022, the Company’s financial assets valued based on Level 1 inputs consisted of cash and cash equivalents in a money market fund, its financial assets valued based on Level 2 inputs consisted of high-grade corporate and government agency bonds and commercial paper, and it had no financial assets valued based on Level 3 inputs. During the years ended December 31, 2023, 2022 and 2021, the Company did not have any transfers of financials assets between Levels 1 and 2. As of December 31, 2023 and 2022, the Company did not have any financial liabilities that were recorded at fair value on a recurring basis on the balance sheet. Research and Development Costs Research and development costs are expensed as incurred. Research and development costs are comprised of costs incurred in performing research and development activities, including internal costs (including stock-based compensation), costs for consultants, milestone payments under licensing agreements, and other costs associated with the Company’s preclinical and clinical programs. In particular, the Company has conducted safety studies in animals, optimized and implemented the manufacturing of its drug, and conducted clinical trials, all of which are considered research and development expenditures. Management uses significant judgment in estimating the amount of research and development costs recognized in each reporting period. Management analyzes and estimates the progress of its clinical trials, completion of milestones events per underlying agreements, invoices received and contracted costs when estimating the research and development costs to accrue in each reporting period. Actual results could differ from the Company’s estimates. Patents Costs to secure and defend patents are expensed as incurred and are classified as general and administrative expense in the Company’s statements of operations. Patent expenses were approximately $0.9 million, $0.5 million and $0.5 million for the years ended December 31, 2023, 2022 and 2021, respectively. Stock-Based Compensation The Company recognizes stock-based compensation expense based on the grant date fair value of stock options, restricted stock units, and other stock-based compensation awards granted to employees, officers, directors, and consultants. Awards that vest as the recipient provides service are expensed on a straight-line basis over the requisite service period. The Company uses the Black-Scholes option pricing model to determine the grant date fair value of stock options as management believes it is the most appropriate valuation method for its option grants. The Black-Scholes model requires inputs for risk-free interest rate, dividend yield, volatility and expected lives of the options. The expected lives for options granted represent the period of time that options granted are expected to be outstanding. The Company uses the simplified method for determining the expected lives of options. Expected volatility is based upon an industry estimate or blended rate including the Company’s historical trading activity. The risk-free rate for periods within the expected life of the option is based on the U.S. Treasury yield curve in effect at the time of the grant. The Company estimates the forfeiture rate based on historical data. This analysis is re-evaluated at least annually and the forfeiture rate is adjusted as necessary. For other stock-based compensation awards granted to employees and directors that vest based on market conditions, such as the trading price of the Company’s common stock achieving or exceeding certain price targets, the Company uses a Monte Carlo simulation model to estimate the grant date fair value and recognize stock compensation expense over the derived service period. The Monte Carlo simulation model requires key inputs for risk-free interest rate, dividend yield, volatility, and expected life. The assumptions used in computing the fair value of equity awards reflect the Company’s best estimates but involve uncertainties related to market and other conditions. Changes in any of these assumptions may materially affect the fair value of awards granted and the amount of stock-based compensation recognized. Certain of the employee stock options granted by the Company are structured to qualify as incentive stock options (ISOs). Under current tax regulations, the Company does not receive a tax deduction for the issuance, exercise or disposition of ISOs if the employee meets certain holding requirements. If the employee does not meet the holding requirements, a disqualifying disposition occurs, at which time the Company may receive a tax deduction. The Company does not record tax benefits related to ISOs unless and until a disqualifying disposition is reported. In the event of a disqualifying disposition, the entire tax benefit is recorded as a reduction of income tax expense. The Company has not recognized any income tax benefit for its share-based compensation arrangements due to the fact that the Company does not believe it is more likely than not it will realize the related deferred tax assets. Income Taxes The Company uses the asset and liability method to account for income taxes. Deferred tax assets and liabilities are determined based on the expected future tax consequences of temporary differences between the Company’s financial statement carrying amounts and the tax basis of assets and liabilities using enacted tax rates expected to be in effect in the years in which the differences are expected to reverse. The Company currently maintains a 100% valuation allowance on its deferred tax assets. Comprehensive Loss Comprehensive loss is defined as the change in equity of a business enterprise during a period from transactions and other events and circumstances from non-owner sources. Changes in unrealized gains and losses on marketable securities represent the only difference between the Company’s net loss and comprehensive loss. Basic and Diluted Loss Per Common Share Basic net loss per share is computed using the weighted average number of common shares outstanding during the period. Diluted net loss per common share is computed using the weighted average number of common shares outstanding and the weighted average dilutive potential common shares outstanding using the treasury stock method. However, for the years ended December 31, 2023, 2022 and 2021, diluted net loss per share is the same as basic net loss per share because the inclusion of weighted average shares of common stock issuable upon the exercise of stock options and warrants or vesting of restricted stock units, and common stock issuable upon the conversion of preferred stock would be anti-dilutive. The following table summarizes outstanding securities not included in the computation of diluted net loss per common share as their inclusion would be anti-dilutive: As of December 31, 2023 2022 2021 Common stock options 2,355,779 2,857,054 2,301,574 Restricted stock units 376,117 — — Performance-based restricted stock units 150,000 — — Preferred stock 2,369,797 2,369,797 1,969,797 Warrants 2,067,552 14,899 — Recent Accounting Pronouncements Not Yet Adopted In November 2023, the Financial Accounting Standards Board (“FASB”) issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which enhances the disclosures required for operating segments in the Company's annual and interim consolidated financial statements. The amendments are effective for fiscal years beginning after December 15, 2023, and interim periods beginning after December 15, 2024. Early adoption is permitted. The Company is currently evaluating the impact of ASU 2023-07 on its financial statements. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which enhances the disclosures required for income taxes in the Company's annual consolidated financial statements. The amendments are effective for annual periods beginning after December 15, 2024. Early adoption is permitted. The Company is currently evaluating the impact of ASU 2023-09 on its financial statements.

Liquidity and Uncertainties

Liquidity and Uncertainties	12 Months Ended
	Dec. 31, 2023
Liquidity and Uncertainties
Liquidity and Uncertainties	Liquidity and Uncertainties The Company is subject to risks common to development stage companies in the biopharmaceutical industry including, but not limited to, uncertainty of product development and commercialization, dependence on key personnel, uncertainty of market acceptance of products and product reimbursement, product liability, uncertain protection of proprietary technology, potential inability to raise additional financing necessary for development and commercialization, and compliance with the U.S. Food and Drug Administration and other government regulations.

Cash, Cash Equivalents and Mark

Cash, Cash Equivalents and Marketable Securities	12 Months Ended
	Dec. 31, 2023
Cash and Cash Equivalents [Abstract]
Cash, Cash Equivalents and Marketable Securities	Cash, Cash Equivalents and Marketable Securities A summary of cash, cash equivalents and available-for-sale marketable securities held by the Company as of December 31, 2023 and 2022 is as follows (in thousands): December 31, 2023 Cost Unrealized Unrealized Fair Cash and cash equivalents: Cash (Level 1) $ 2,729 $ — $ — $ 2,729 Money market funds (Level 1) 78,555 — — 78,555 US government and government sponsored entities (Level 1) 14,967 — — 14,967 Corporate debt securities due within 3 months of date of purchase (Level 2) 3,664 — — 3,664 Total cash and cash equivalents 99,915 — — 99,915 Marketable securities: Corporate debt securities due within 1 year of date of purchase (Level 2) 382,028 195 (7) 382,216 US government and government sponsored entities due within 1 year of date of purchase (Level 2) 150,743 280 (1) 151,022 Corporate debt securities due within 1 to 2 years of date of purchase (Level 2) $ 977 $ 1 $ — $ 978 Total cash, cash equivalents and marketable securities $ 633,663 $ 476 $ (8) $ 634,131 December 31, 2022 Cost Unrealized Unrealized losses Fair Cash and cash equivalents: Cash (Level 1) $ 15,100 $ — $ — $ 15,100 Money market funds (Level 1) 316,449 — — 316,449 Total cash and cash equivalents 331,549 — — 331,549 Marketable securities: Corporate debt securities due within 1 year of date of purchase (Level 2) 27,257 7 (39) 27,225 Total cash, cash equivalents and marketable securities $ 358,806 $ 7 $ (39) $ 358,774

Accrued Liabilities

Accrued Liabilities	12 Months Ended
	Dec. 31, 2023
Accrued Liabilities, Current [Abstract]
Accrued Liabilities	Accrued Liabilities Accrued liabilities as of December 31, 2023 and 2022 consisted of the following (in thousands): December 31, December 31, Contract research organization costs $ 50,737 $ 53,119 Other clinical study related costs 3,724 6,582 Manufacturing and drug supply 9,705 11,262 Compensation and benefits 17,030 14,864 Professional fees 6,814 4,867 Other 1,970 767 Total accrued liabilities $ 89,980 $ 91,461

Long Term Debt

Long Term Debt	12 Months Ended
	Dec. 31, 2023
Debt Disclosure [Abstract]
Long Term Debt	Long Term Debt In May 2022 the Company and its wholly-owned subsidiary, Canticle Pharmaceuticals, Inc., entered into the $250.0 million Loan Facility (the “Loan Facility”) with several banks and other financial institutions or entities party thereto (each, a “Lender” and collectively referred to as the “Lenders”), and Hercules Capital, Inc. (“Hercules”), in its capacity as administrative agent and collateral agent for itself and the Lenders. Under the terms of the Loan Facility, the first $50.0 million tranche was drawn at closing. The Company may also draw up to an additional $125.0 million in two separate tranches upon achievement of certain resmetirom clinical and regulatory milestones. A fourth tranche of $75.0 million may be drawn by the Company, subject to the approval of Hercules. The Loan Facility had a minimum interest rate of 7.45% and adjusted with changes in the prime rate. The Company will pay interest-only monthly payments of accrued interest under the Loan Facility through May 1, 2025, for a period of 36 months, which period may be extended to May 1, 2026 and May 3, 2027, upon the achievement of regulatory approval milestones and future revenue covenants, subject to compliance with applicable covenants. The Loan Facility matures in May 2026 and may be extended an additional year upon the achievement of certain regulatory milestones. The Loan Facility is secured by a security interest in substantially all of the Company’s assets, other than intellectual property. It includes an end of term charge of 5.35% of the aggregate principal amount, which is accounted for in the loan discount. In connection with the first tranche drawn at closing, the Company issued Hercules a warrant to purchase 14,899 shares of Company common stock, which had a Black-Scholes value of $0.6 million. On February 3, 2023, the Company entered into the First Amendment (the “Amendment”) to the Loan Facility (as amended, the “Amended Loan Facility”). Under the Amended Loan Facility, an additional $35.0 million was drawn under a second, expanded, $65.0 million tranche (“Tranche 2”) in February of 2023 following the Company’s achievement of the Phase 3 clinical development milestone. An additional $15.0 million was drawn under Tranche 2 in June of 2023. The remaining $15.0 million available under Tranche 2 was drawn in September of 2023 in accordance with the Amended Loan Facility. The third tranche (“Tranche 3”) of $75.0 million remains unchanged by the Amendment, and such borrowings are available subject to the Company obtaining a certain FDA approval for resmetirom. Coincident with the expansion of Tranche 2 borrowing capacity by $15.0 million, the Amendment reduced the fourth tranche under the Loan Facility (“Tranche 4”) by $15.0 million to $60.0 million, which amount is available subject to Hercules’ sole discretion. In connection with the $35.0 million drawn under Tranche 2 at the closing of the Amendment, $15.0 million drawn in June of 2023, and $15.0 million drawn in September of 2023, the Company issued to Hercules and affiliates Tranche 2 Warrants to purchase an aggregate of 4,555 shares of common stock, which had a Black-Scholes value of $0.9 million. The Amendment reduced the interest rate under the Amended Loan Facility to the greater of (i) the prime rate as reported in The Wall Street Journal plus 2.45% and (ii) 8.25%. The Amendment and the Amended Loan Facility summary terms were disclosed in the Company’s Current Report on Form 8-K filed with the Securities and Exchange Commission on February 9, 2023. The Loan Facility includes affirmative and restrictive financial covenants which commenced on January 1, 2023, including maintenance of a minimum cash, cash equivalents and liquid funds covenant of $35.0 million, which may decrease in certain circumstances if the Company achieves certain clinical milestones and a revenue milestone, and a revenue-based covenant that could apply commencing at or after the time that financial reporting is due for the quarter ending September 30, 2024. The Loan Facility contains event of default provisions for: the Company’s failure to make required payments or maintain compliance with covenants under the Loan Facility; the Company’s breach of certain representations or default under certain obligations outside the Loan Facility; insolvency, attachment or judgment events affecting the Company; and any circumstance which has occurred or could reasonably be expected to have a material adverse effect on the Company, provided that, any failure to achieve approval or certain other milestones under the Loan Facility shall not in and of itself constitute a material adverse effect. The Loan Facility also includes customary covenants associated with a secured loan facility, including covenants concerning financial reporting obligations, and certain limitations on indebtedness, liens (including a negative pledge on intellectual property and other assets), investments, distributions (including dividends), collateral, investments, distributions, transfers, mergers or acquisitions, taxes, corporate changes, and deposit accounts. As of December 31, 2023, the outstanding principal under the Loan Facility was $115.0 million. The interest rate as of December 31, 2023 was 10.95%. As of December 31, 2023, the Company was in compliance with all loan covenants and provisions. Future minimum payments, including interest and principal, under the loans payable outstanding as of December 31, 2023 are as follows (in thousands): Period Ending December 31, 2023: Amount 2024 $ 12,802 2025 79,604 2026 53,387 $ 145,793 Less amount representing interest (24,641) Less unamortized discount (5,672) Loans payable, net of discount $ 115,480

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2023
Equity [Abstract]
Stockholders' Equity	Stockholders’ Equity Common Stock Each common stockholder is entitled to one vote for each share of common stock held. The common stock will vote together with all other classes and series of stock of the Company as a single class on all actions to be taken by the Company’s stockholders. Each share of common stock is entitled to receive dividends, as and when declared by the Company’s Board of Directors ("The Board"). The Company has never declared cash dividends on its common stock and does not expect to do so in the foreseeable future. Preferred Stock The Series A and B Preferred Stock have a par value of $0.0001 per share and are convertible into shares of the common stock at a one-to-one ratio, subject to adjustment as provided in the Certificates of Designation of Preferences, Rights and Limitations of Series A Preferred Stock and Series B Preferred Stock that the Company filed with the Secretary of State of the State of Delaware on June 21, 2017 and December 22, 2022, respectively. The terms of the Series A and B Preferred Stock are set forth in such Certificates of Designation. Each share of the Series A and B Preferred Stock is convertible into shares of Common Stock following notice that may be given at the holder’s option. Upon any liquidation, dissolution or winding-up of the Company, whether voluntary or involuntary, after the satisfaction in full of the debts of the Company and the payment of any liquidation preference owed to the holders of shares of capital stock of the Company ranking prior to the Series A and B Preferred Stock upon liquidation, the holders of the Series A and B Preferred Stock shall participate pari passu with the holders of the Common Stock (on an as-if-converted-to-Common-Stock basis) in the net assets of the Company. Shares of the Series A and B Preferred Stock will generally have no voting rights, except as required by law. Shares of the Series A and B Preferred Stock will be entitled to receive dividends before shares of any other class or series of capital stock of the Company (other than dividends in the form of the Common Stock) equal to the dividend payable on each share of the Common Stock, on an as-converted basis. 2023 Public Offering On September 28, 2023, the Company entered into an Underwriting Agreement with Goldman Sachs & Co. LLC, as representative of the several underwriters named therein, pursuant to which the Company sold to the underwriters in an underwritten public offering (the “2023 Offering”): (i) 1,248,098 shares of common stock at a public offering price of $151.69 per share, and (ii) pre-funded warrants (the “Pre-Funded Warrants”) to purchase 2,048,098 shares of common stock at a public offering price of $151.6899 per Pre-Funded Warrant, which represents the per share public offering price for the common stock less a $0.0001 per share exercise price for each such Pre-Funded Warrant. The 2023 Offering closed on October 3, 2023. The gross proceeds of the 2023 Offering was $500.0 million, and the Company received net proceeds, after deducting the underwriting discount and commissions and other estimated offering expenses payable by the Company, of approximately $472.0 million. The Company intends to use the net proceeds from the Offering for its clinical and commercial activities in preparation for a potential launch of resmetirom in the U.S. and for general corporate purposes, including, without limitation, research and development expenditures, clinical trial expenditures, manufacture and supply of drug substance and drug products, potential acquisitions or licensing of new technologies, capital expenditures and working capital. The Pre-Funded Warrants are exercisable at any time after the date of issuance. A holder of Pre-Funded Warrants may not exercise the warrant if the holder, together with its affiliates, would beneficially own more than 9.99% of the number of shares of common stock outstanding immediately after giving effect to such exercise. A holder of Pre-Funded Warrants may increase or decrease this percentage, but not in excess of 19.99%, by providing at least 61 days prior notice to the Company. December 2022 Registered Direct Offering In December 2022, the Company entered into a Securities Purchase Agreement (the “Purchase Agreement”) with a group of institutional accredited investors, who were existing, non-controlling stockholders of the Company, pursuant to which the Company sold securities to the Investors in an offering that was registered under the Company’s existing shelf registration statement (the “2022 Registered Direct Offering”). Under the terms of the Purchase Agreement, the Company sold 44,444 shares of its common stock at a price of $225 per share, and 400,000 shares of its Series B Convertible Preferred Stock at a price of $225 per share. The 2022 Registered Direct Offering resulted in gross proceeds to the Company of approximately $100.0 million, and net proceeds to the Company of approximately $99.5 million. The 2022 Registered Direct Offering closed on December 23, 2022. At-The-Market Issuance Sales Agreement In November 2020, the Company entered into an at-the-market sales agreement (the “2020 Sales Agreement”), with Cowen and Company, LLC (“Cowen”), pursuant to which the Company could, from time to time, issue and sell shares of its common stock. The 2020 Sales Agreement authorized an aggregate offering of up to $200.0 million in shares of our common stock, at the Company’s option, through Cowen as its sales agent. Sales of common stock through Cowen could be made by any method that is deemed an “at-the-market” offering as defined in Rule 415 promulgated under the Securities Act of 1933, as amended, including by means of ordinary brokers’ transactions at market prices, in block transactions or as otherwise agreed by the Company and Cowen. The 2020 Sales Agreement was terminated in June 2021 when the Company filed a new shelf registration statement. Under the 2020 Sales Agreement the Company sold 1,126,733 shares for an aggregate of approximately $137.4 million in gross proceeds, with net proceeds to the Company of approximately $134.8 million after deducting commissions and other transaction costs. Of those shares sold, 1,087,126 were sold in 2021, and 39,607 were sold in 2020. In June 2021, the Company entered into an at-the-market sales agreement (the “Original 2021 Sales Agreement”) with Cowen and Company, LLC (“Cowen”), pursuant to which the Company could, from time to time, issue and sell shares of its common stock. The Original 2021 Sales Agreement authorized an aggregate offering of up to $200.0 million in shares of our common stock, at the Company’s option, through Cowen as its sales agent. Sales of common stock through Cowen could be made by any method that is deemed an “at-the-market” offering as defined in Rule 415 promulgated under the Securities Act of 1933, as amended, including by means of ordinary brokers’ transactions at market prices, in block transactions or as otherwise agreed by the Company and Cowen. Subject to the terms and conditions of the Original 2021 Sales Agreement, Cowen would use commercially reasonable efforts consistent with its normal trading and sales practices to sell the common stock based upon the Company’s instructions (including any price, time or size limits or other customary parameters or conditions the Company imposed). In December 2022, the Company sold 738,900 shares under the Original 2021 Sales Agreement for an aggregate of $159.1 million in gross proceeds, with net proceeds to the Company of $155.9 million after deducting commissions and other transaction costs. In total, under the Original 2021 Sales Agreement the Company sold 1,235,943 shares for an aggregate of $199.9 million in gross proceeds, with net proceeds to the Company of approximately $195.8 million after deducting commissions and other transaction costs. Of those shares sold, 738,900 were sold in 2022, and 497,043 were sold in 2021. All shares were sold pursuant to the Company’s effective shelf registration statement on Form S-3 ( the "Registration Statement") and the prospectus supplement relating thereto. As of December 31, 2023, no amounts remained reserved and available for sale under the Original 2021 Sales Agreement and the related prospectus supplement. In May 2023, the Company amended the 2021 Agreement (the “Sales Agreement Amendment”), with Cowen, pursuant to which the Company may, from time to time, issue and sell an additional $200.0 million in shares of its common stock. The Company is not obligated to make any sales of its common stock under this arrangement. Any shares sold will be sold pursuant to the Registration Statement and prospectus supplement filed pursuant to the Registration Statement. The Sales Agreement Amendment authorizes sales of shares of the Company’s common stock, from time to time, at the Company’s option, through Cowen as its sales agent. Sales of common stock through Cowen may be made by any method that is deemed an “at-the-market” offering as defined in Rule 415 promulgated under the Securities Act of 1933, as amended, and as described in the prospectus supplement. During the three months ended December 31, 2023, under the Sales Agreement Amendment, the Company sold no shares. During the year ended December 31, 2023, and in total under the Sales Agreement Amendment, the Company sold 98,101 shares for an aggregate of $25.2 million in gross proceeds, with net proceeds to the Company of approximately $24.5 million after deducting commissions and other transaction costs. All shares were sold pursuant to the Company’s effective Registration Statement and the prospectus supplement relating thereto. As of December 31, 2023, $174.8 million remained reserved and available for sale under the 2023 Sales Agreement Amendment and the Company’s related prospectus supplement.

Stock-based Compensation

Stock-based Compensation	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Stock-based Compensation	Stock-based Compensation 2015 Stock Plan The 2015 Stock Plan, as amended (the “2015 Stock Plan”), is our shareholder-approved incentive plan through which equity based grants are awarded. The 2015 Stock Plan provides for the grant of incentive stock options, non-statutory stock options, restricted stock, restricted stock units and other stock-based compensation awards to employees, officers, directors, and consultants of the Company. The administration of the 2015 Stock Plan is under the general supervision of the Compensation Committee of the Board of Directors. The terms of stock options awarded under the 2015 Stock Plan, in general, are determined by the Compensation Committee, provided the exercise price per share generally shall not be set at less than the fair market value of a share of the common stock on the date of grant and the term shall not be greater than ten years from the date the option is granted. As of December 31, 2023, 711,054 shares were available for future issuance under the 2015 Stock Plan. 2023 Inducement Plan In September 2023, the Company adopted the 2023 Inducement Plan (the “Inducement Plan”), pursuant to which the Company may from time to time make equity grants to new employees as a material inducement to their employment. The Inducement Plan was adopted without stockholder approval, pursuant to Nasdaq Listing Rule 5635(c)(4), and is administered by the Compensation Committee of the Board. The Inducement Plan provides for the granting of non-statutory stock options, restricted stock, restricted stock units, performance stock units and other stock-based compensation awards to new employees, but does not allow for the granting of incentive stock options. The terms of the stock options under the Inducement Plan, in general, are determined by the Compensation Committee, provided the exercise price per share generally shall not be set at less than the fair market value of a share of the common stock on the date of grant and the term shall not be greater than ten years from the date the option or award is granted. A total of 500,000 shares of the Company’s common stock were reserved for issuance under the Inducement Plan. As of December 31, 2023, 193,392 shares were available for future issuance under the 2023 Inducement Plan. Stock Options The following table summarizes stock option activity during the year ended December 31, 2023: Shares Weighted Weighted Aggregate Outstanding at January 1, 2023 2,857,054 $ 81.78 Options granted 31,111 190.91 Options exercised (460,385) 88.83 Options cancelled (72,001) 144.24 Outstanding at December 31, 2023 2,355,779 $ 79.94 5.51 $ 359,861 Exercisable at December 31, 2023 1,774,976 $ 74.49 4.71 $ 281,400 The total cash received by the Company as a result of stock option exercises was $34.0 million, $9.0 million and $1.0 million for the years ended December 31, 2023, 2022, and 2021. The total intrinsic value of options exercised was $70.4 million $47.3 million and $0.1 million for the years ended December 31, 2023, 2022, and 2021. The weighted-average grant date fair values, based on the Black-Scholes option model, of options granted during the year ended December 31, 2023, 2022 and 2021 was $149.15, $54.68, and $73.29, respectively. Restricted Stock Units The Company’s 2015 Stock Plan provides for awards of restricted stock units (“RSUs”) to employees, officers, directors and consultants to the Company. The Company’s Inducement Plan provides for awards of RSUs to new employees. RSUs vest over a period of months or years, or upon the occurrence of certain performance criteria or the attainment of stated goals or events, and are subject to forfeiture if employment or service terminates before vesting. The following table summarizes RSU activity, excluding performance-based RSUs, during the year ended December 31, 2023: Shares Weighted average grant date fair value Unvested at January 1, 2023 — $ — RSUs granted 398,600 243.81 RSUs vested (356) 299.98 RSUs forfeited (22,127) 283.05 Unvested at December 31, 2023 376,117 $ 241.45 Performance-Based Restricted Stock Units The Company has granted various performance-based restricted stock units (“PSUs”) to certain senior leadership. Depending on the terms of the PSUs and the outcome of the pre-established performance criteria, which may include a market and/or performance condition, a recipient may ultimately earn the target number of PSUs granted or a specified multiple thereof at the end of the vesting period. As of December 31, 2023, the Company granted 50,000 PSUs. The maximum number of PSUs eligible to be earned of 150,000 are outstanding under the Inducement Plan as of December 31, 2023, with a weighted average grant date fair value of $146.37 per unit. Outstanding Awards As of December 31, 2023, the Company had restricted stock units, performance stock units, and options outstanding pursuant to which an aggregate of 2,881,896 shares of its common stock may be issued pursuant to the terms of all awards granted under the 2015 Stock Plan and Inducement Plan. Stock-Based Compensation Expense Stock-based compensation expense during the years ended December 31, 2023, 2022 and 2021 was as follows (in thousands): Year Ended December 31, 2023 2022 2021 Stock-based compensation expense by type of award: Stock options $ 30,613 $ 31,625 $ 26,873 Restricted stock units 14,974 — — Performance-based restricted stock units 4,148 — — Total stock-based compensation expense $ 49,735 $ 31,625 $ 26,873 Effect of stock-based compensation expense by line item: Research and development $ 20,864 $ 13,876 $ 10,698 General and administrative 28,871 17,749 16,175 Total stock-based compensation expense included in net loss $ 49,735 $ 31,625 $ 26,873

Leases

Leases	12 Months Ended
	Dec. 31, 2023
Leases [Abstract]
Leases	Leases In 2019, the Company entered into an operating lease for office space, which was renewed and extended in 2020. The Company adopted ASU 2016-02, “Leases,” on January 1, 2019 requiring, among other changes, operating and finance leases with terms exceeding twelve months to be recognized as a right-of-use asset (or “ROU”) and lease liabilities on the balance sheet. Operating lease ROU assets and operating lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term at the commencement date. The lease term is determined to be the non-cancelable period including any lessee renewal options that are considered reasonably certain of exercise. The interest rate implicit in lease contracts is typically not readily determinable. As such, the Company used judgment to determine an appropriate incremental borrowing rate, which is the rate incurred to borrow on a collateralized basis over a similar term in a similar economic environment. In August 2023, The Company entered into the Fifth Amendment to its Office Lease (the “Lease Amendment”). The Lease Amendment extends the term of the lease through November 2026. As a result of the Lease Amendment, an incremental $1.6 million ROU asset and lease liabilities were recorded during the year ended December 31, 2023. Future minimum payments under the Company’s operating leases related to the ROU asset and lease liability as of December 31, 2023 was as follows (in thousand): Operating Leases 2024 937 2025 478 2026 446 Total minimum payments $ 1,861 Less: imputed interest (148) Present value of lease liabilities $ 1,713

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies The Company has a Research, Development and Commercialization Agreement with Hoffmann-La Roche (“Roche”) which grants the Company a sole and exclusive license to develop, use, sell, offer for sale and import any Licensed Product as defined by the agreement. The agreement requires future milestone payments to Roche. Remaining milestones under the agreement total $8.0 million and are earned by achieving specified objectives related to future regulatory approval in the United States and Europe of resmetirom or a product developed from resmetirom. Furthermore, a tiered single-digit royalty is payable on net sales of resmetirom or a product developed from resmetirom, subject to certain reductions. The Company has not achieved any additional product development or regulatory milestones and had no Licensed Product sales for the years ended December 31, 2023, 2022 and 2021. In August 2023, The Company entered into the Fifth Amendment to the Office Lease (the "Lease Amendment"). The Lease Amendment extends the term of the lease through November 2026. As a result of the Lease Amendment, an incremental $1.6 million ROU asset and lease liabilities were recorded during the year ended December 31, 2023.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes At December 31, 2023, the Company had federal net operating loss (“NOL”) carryforwards of approximately $489.0 million available to reduce future taxable income, of which $40.4 million will expire between 2031 and 2037. The Company also has state operating loss carryforwards of approximately $477.6 million, available to reduce future taxable income, which expire between 2031 and 2042. The Company has unused federal research and development carryforwards of approximately $46.1 million which will begin to expire in 2031. The Internal Revenue Code (“IRC”) limits the amounts of NOL carryforwards that a Company may use in any one year in the event of certain cumulative changes in ownership over a three-year period as described in Section 382 of the IRC. Such change in ownership could limit the Company’s utilization of the NOL, and could be triggered by subsequent sales of securities by the Company or stockholders. The deferred tax asset related to the NOL reflected on the financial statements could be affected by this limitation. Although a formal analysis has not been completed, the Company has determined that an ownership change likely occurred for Madrigal during the year ended December 31, 2017. The net operating losses are estimated to be subject to an annual limitation, of which none are expected to expire before becoming available to reduce future taxable income. In assessing the realizability of deferred tax assets, management considers whether it is more likely than not that some portion of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible. As there is no assurance of future taxable income, a full valuation allowance has been established to offset the deferred tax assets. The valuation allowance increased $112.0 million for the year ended December 31, 2023. Changes in the deferred tax asset will be recorded as an income tax benefit or expense on the accompanying consolidated statements of operations. Entities are also required to evaluate, measure, recognize and disclose any uncertain income tax provisions taken on their income tax returns. The Company has analyzed its tax positions and has concluded that as of December 31, 2023 there were no uncertain positions. The 2019 through 2023 tax returns are open to review by the IRS and state taxing authorities. Interest and penalties, if any, as they relate to income taxes assessed, are included in the income tax provision. There was no income tax related interest and penalties included in the income tax provision for 2023. Temporary differences that give rise to deferred tax assets and liabilities are as follows (in thousands): For the years ended December 31, 2023 2022 2021 Deferred Tax Liabilities Unrealized gains on investments $ 117 $ — $ — Total Deferred Tax Liabilities $ 117 $ — $ — Deferred Tax Assets Charitable contributions $ 37 $ 45 $ 53 Accrued expenses 3,857 2,398 1,857 Intangibles 503 589 783 Stock compensation 33,976 27,226 24,335 Property, plant & equipment 95 106 80 Unrealized loss on investment — 8 23 Net operating losses 121,552 68,305 47,864 Capitalized R&D 175,145 137,328 112,848 R&D credit 48,074 35,103 23,799 Total deferred tax assets before valuation allowance 383,239 271,108 211,642 Valuation allowance (383,122) (271,108) (211,642) Total deferred tax assets 117 — — Net deferred tax assets $ — $ — $ — Differences between the effective income tax rate and the US statutory rate were as follows (in thousands): For the years ended December 31, 2023 2022 2021 Tax benefit at U.S. federal statutory rate $ (78,462) $ (62,023) $ (50,788) Stock based compensation (8,287) (7,844) — 162M limitation 3,183 7,996 22 Other nondeductible expenses 53 16 5 State income taxes benefit before valuation allowance, net of federal benefit (16,246) 13,090 (19,622) Increase in domestic valuation allowance 112,606 59,466 79,258 Research and development credit (12,971) (10,712) (9,002) Other adjustments 124 11 127 Income tax expense (benefit) $ — $ — $ —

Quarterly Financial Data (unaud

Quarterly Financial Data (unaudited)	12 Months Ended
	Dec. 31, 2023
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Data (unaudited)	Quarterly Financial Data (unaudited) The following tables present a summary of quarterly results of operations for 2023 and 2022 (in thousands, except shares and per share data): Three months ended March 31, 2023 June 30, 2023 September 30, 2023 December 31, Revenues: Total revenues $ — $ — $ — $ — Operating expenses: Research and development 62,154 68,605 70,951 70,640 General and administrative 16,182 17,845 27,583 46,536 Total operating expenses 78,336 86,450 98,534 117,176 Loss from operations (78,336) (86,450) (98,534) (117,176) Interest income 3,776 3,551 3,298 8,953 Interest expense (2,336) (2,901) (3,504) (3,971) Other income — — — — Net loss $ (76,896) $ (85,800) $ (98,740) $ (112,194) Net loss per common share: Basic and diluted net loss per common share $ (4.23) $ (4.69) $ (5.34) $ (5.68) Basic and diluted weighted average number of common shares outstanding 18,187,924 18,310,952 18,476,414 19,760,842 Three months ended March 31, 2022 June 30, 2022 September 30, 2022 December 31, Revenues: Total revenues $ — $ — $ — $ — Operating expenses: Research and development 47,929 58,499 68,271 70,742 General and administrative 9,658 11,774 12,141 14,557 Total operating expenses 57,587 70,273 80,412 85,299 Loss from operations (57,587) (70,273) (80,412) (85,299) Interest income 69 323 717 1,076 Interest expense — (780) (1,502) (1,682) Other income — — — — Net loss $ (57,518) $ (70,730) $ (81,197) $ (85,905) Net loss per common share: Basic and diluted net loss per common share $ (3.36) $ (4.14) $ (4.75) $ (4.98) Basic and diluted weighted average number of common shares outstanding 17,103,395 17,103,395 17,103,395 17,237,517

Subsequent Event

Subsequent Event	12 Months Ended
	Dec. 31, 2023
Subsequent Events [Abstract]
Subsequent Event	Subsequent Event None.

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pay vs Performance Disclosure
Net loss	$ (112,194)	$ (98,740)	$ (85,800)	$ (76,896)	$ (85,905)	$ (81,197)	$ (70,730)	$ (57,518)	$ (373,630)	$ (295,350)	$ (241,846)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended	12 Months Ended
	Dec. 31, 2023 shares	Dec. 31, 2023 shares
Trading Arrangements, by Individual
Material Terms of Trading Arrangement		Director and Executive Officer Adoption of 10b5-1 Plans Our Section 16 officers and directors may enter into plans or arrangements for the purchase or sale of our securities that are intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) of the Exchange Act. Such plans and arrangements must comply in all respects with our insider trading policies, including our policy governing entry into and operation of 10b5-1 plans and arrangements. During the quarter ended December 31, 2023: the following Section 16 officers and directors adopted Rule 10b5-1 trading arrangements (as defined in Item 408 of Regulation S-K of the Exchange Act); and no plans were modified or terminated. All plans adopted covered sales of Madrigal common stock (including sales of Madrigal common stock following exercise of stock options). Name of Director or Section 16 Officer Title of Director or Section 16 Officer Date of Adoption, Modification, or Termination Duration of the Plan Aggregate Number of Shares of Common Stock that may be Sold under the Plan Becky Taub, MD President of R&D, CMO and Director 11/27/2023 April 3, 2025 76,564 Kenneth Bate Director 11/16/2023 June 27, 2024 32,489 James Daly Director 11/16/2023 June 27, 2024 32,489 Paul Friedman, MD Director 11/27/2023 April 3, 2025 100,000 Richard Levy, MD Director 11/30/2023 June 16, 2025 26,000
Rule 10b5-1 Arrangement Adopted	true
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false
Becky Taub [Member]
Trading Arrangements, by Individual
Name	Becky Taub, MD
Title	President of R&D, CMO and Director
Adoption Date	11/27/2023
Termination Date	April 3, 2025
Arrangement Duration	493 days
Aggregate Available	76,564	76,564
Kenneth Bate [Member]
Trading Arrangements, by Individual
Name	Kenneth Bate
Title	Director
Adoption Date	11/16/2023
Termination Date	June 27, 2024
Arrangement Duration	224 days
Aggregate Available	32,489	32,489
James Daly [Member]
Trading Arrangements, by Individual
Name	James Daly
Title	Director
Adoption Date	11/16/2023
Termination Date	June 27, 2024
Arrangement Duration	224 days
Aggregate Available	32,489	32,489
Paul Friedman [Member]
Trading Arrangements, by Individual
Name	Paul Friedman, MD
Title	Director
Adoption Date	11/27/2023
Termination Date	April 3, 2025
Arrangement Duration	493 days
Aggregate Available	100,000	100,000
Richard Levy [Member]
Trading Arrangements, by Individual
Name	Richard Levy, MD
Title	Director
Adoption Date	11/30/2023
Termination Date	June 16, 2025
Arrangement Duration	564 days
Aggregate Available	26,000	26,000

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Principle of Consolidation	Principle of Consolidation
Use of Estimates	Use of Estimates
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments with original maturities of three months or less at the date of purchase to be cash equivalents. The Company maintains its cash in bank accounts, the balance of which, at times, exceeds Federal Deposit Insurance Corporation insured limits.
Marketable Securities	Marketable Securities Marketable securities consist of investments in high-grade corporate obligations, and government and government agency obligations that are classified as available-for-sale. Since these securities are available to fund current operations they are classified as current assets on the consolidated balance sheets. The Company adjusts the cost of available-for-sale debt securities for amortization of premiums and accretion of discounts to maturity. The Company includes such amortization and accretion as a component of interest income, net. Realized gains and losses and declines in value, if any, that the Company judges to be the result of impairment or as a result of recognizing an allowance for credit losses on available-for-sale securities are reported as a component of interest income. To determine whether an impairment exists, the Company considers whether it intends to sell the debt security and, if the Company does not intend to sell the debt security, it considers available evidence to assess whether it is more likely than not that it will be required to sell the security before the recovery of its amortized cost basis. During the years ended December 31, 2023, 2022 and 2021, the Company determined it did not have any securities that were other-than-temporarily impaired.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The carrying amounts of the Company’s financial instruments, which include cash equivalents, and marketable securities, approximate their fair values. The fair value of the Company’s financial instruments reflects the amounts that would be received upon sale of an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The fair value hierarchy has the following three levels: Level 1—quoted prices in active markets for identical assets and liabilities. Level 2—observable inputs other than Level 1 inputs. Examples of Level 2 inputs include quoted prices in active markets for similar assets or liabilities and quoted prices for identical assets or liabilities in markets that are not active. Level 3—unobservable inputs that reflect the Company’s own assumptions about the assumptions market participants would use in pricing the asset or liability.
Research and Development Costs	Research and Development Costs Research and development costs are expensed as incurred. Research and development costs are comprised of costs incurred in performing research and development activities, including internal costs (including stock-based compensation), costs for consultants, milestone payments under licensing agreements, and other costs associated with the Company’s preclinical and clinical programs. In particular, the Company has conducted safety studies in animals, optimized and implemented the manufacturing of its drug, and conducted clinical trials, all of which are considered research and development expenditures. Management uses significant judgment in estimating the amount of research and development costs recognized in each reporting period. Management analyzes and estimates the progress of its clinical trials, completion of milestones events per underlying agreements, invoices received and contracted costs when estimating the research and development costs to accrue in each reporting period. Actual results could differ from the Company’s estimates.
Patents	Patents
Stock-Based Compensation	Stock-Based Compensation The Company recognizes stock-based compensation expense based on the grant date fair value of stock options, restricted stock units, and other stock-based compensation awards granted to employees, officers, directors, and consultants. Awards that vest as the recipient provides service are expensed on a straight-line basis over the requisite service period. The Company uses the Black-Scholes option pricing model to determine the grant date fair value of stock options as management believes it is the most appropriate valuation method for its option grants. The Black-Scholes model requires inputs for risk-free interest rate, dividend yield, volatility and expected lives of the options. The expected lives for options granted represent the period of time that options granted are expected to be outstanding. The Company uses the simplified method for determining the expected lives of options. Expected volatility is based upon an industry estimate or blended rate including the Company’s historical trading activity. The risk-free rate for periods within the expected life of the option is based on the U.S. Treasury yield curve in effect at the time of the grant. The Company estimates the forfeiture rate based on historical data. This analysis is re-evaluated at least annually and the forfeiture rate is adjusted as necessary. For other stock-based compensation awards granted to employees and directors that vest based on market conditions, such as the trading price of the Company’s common stock achieving or exceeding certain price targets, the Company uses a Monte Carlo simulation model to estimate the grant date fair value and recognize stock compensation expense over the derived service period. The Monte Carlo simulation model requires key inputs for risk-free interest rate, dividend yield, volatility, and expected life. The assumptions used in computing the fair value of equity awards reflect the Company’s best estimates but involve uncertainties related to market and other conditions. Changes in any of these assumptions may materially affect the fair value of awards granted and the amount of stock-based compensation recognized. Certain of the employee stock options granted by the Company are structured to qualify as incentive stock options (ISOs). Under current tax regulations, the Company does not receive a tax deduction for the issuance, exercise or disposition of ISOs if the employee meets certain holding requirements. If the employee does not meet the holding requirements, a disqualifying disposition occurs, at which time the Company may receive a tax deduction. The Company does not record tax benefits related to ISOs unless and until a disqualifying disposition is reported. In the event of a disqualifying disposition, the entire tax benefit is recorded as a reduction of income tax expense. The Company has not recognized any income tax benefit for its share-based compensation arrangements due to the fact that the Company does not believe it is more likely than not it will realize the related deferred tax assets.
Income Taxes	Income Taxes
Comprehensive Loss	Comprehensive Loss
Basic and Diluted Loss Per Common Share	Basic and Diluted Loss Per Common Share Basic net loss per share is computed using the weighted average number of common shares outstanding during the period. Diluted net loss per common share is computed using the weighted average number of common shares outstanding and the weighted average dilutive potential common shares outstanding using the treasury stock method. However, for the years ended December 31, 2023, 2022 and 2021, diluted net loss per share is the same as basic net loss per share because
Recent Accounting Pronouncements Not Yet Adopted	Recent Accounting Pronouncements Not Yet Adopted In November 2023, the Financial Accounting Standards Board (“FASB”) issued ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which enhances the disclosures required for operating segments in the Company's annual and interim consolidated financial statements. The amendments are effective for fiscal years beginning after December 15, 2023, and interim periods beginning after December 15, 2024. Early adoption is permitted. The Company is currently evaluating the impact of ASU 2023-07 on its financial statements. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which enhances the disclosures required for income taxes in the Company's annual consolidated financial statements. The amendments are effective for annual periods beginning after December 15, 2024. Early adoption is permitted. The Company is currently evaluating the impact of ASU 2023-09 on its financial statements.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	The following table summarizes outstanding securities not included in the computation of diluted net loss per common share as their inclusion would be anti-dilutive: As of December 31, 2023 2022 2021 Common stock options 2,355,779 2,857,054 2,301,574 Restricted stock units 376,117 — — Performance-based restricted stock units 150,000 — — Preferred stock 2,369,797 2,369,797 1,969,797 Warrants 2,067,552 14,899 —

Cash, Cash Equivalents and Ma_2

Cash, Cash Equivalents and Marketable Securities (Tables)	12 Months Ended
	Dec. 31, 2023
Cash and Cash Equivalents [Abstract]
Summary of Cash, Cash Equivalents and Investments	A summary of cash, cash equivalents and available-for-sale marketable securities held by the Company as of December 31, 2023 and 2022 is as follows (in thousands): December 31, 2023 Cost Unrealized Unrealized Fair Cash and cash equivalents: Cash (Level 1) $ 2,729 $ — $ — $ 2,729 Money market funds (Level 1) 78,555 — — 78,555 US government and government sponsored entities (Level 1) 14,967 — — 14,967 Corporate debt securities due within 3 months of date of purchase (Level 2) 3,664 — — 3,664 Total cash and cash equivalents 99,915 — — 99,915 Marketable securities: Corporate debt securities due within 1 year of date of purchase (Level 2) 382,028 195 (7) 382,216 US government and government sponsored entities due within 1 year of date of purchase (Level 2) 150,743 280 (1) 151,022 Corporate debt securities due within 1 to 2 years of date of purchase (Level 2) $ 977 $ 1 $ — $ 978 Total cash, cash equivalents and marketable securities $ 633,663 $ 476 $ (8) $ 634,131 December 31, 2022 Cost Unrealized Unrealized losses Fair Cash and cash equivalents: Cash (Level 1) $ 15,100 $ — $ — $ 15,100 Money market funds (Level 1) 316,449 — — 316,449 Total cash and cash equivalents 331,549 — — 331,549 Marketable securities: Corporate debt securities due within 1 year of date of purchase (Level 2) 27,257 7 (39) 27,225 Total cash, cash equivalents and marketable securities $ 358,806 $ 7 $ (39) $ 358,774

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	12 Months Ended
	Dec. 31, 2023
Accrued Liabilities, Current [Abstract]
Schedule of Accrued Liabilities	Accrued liabilities as of December 31, 2023 and 2022 consisted of the following (in thousands): December 31, December 31, Contract research organization costs $ 50,737 $ 53,119 Other clinical study related costs 3,724 6,582 Manufacturing and drug supply 9,705 11,262 Compensation and benefits 17,030 14,864 Professional fees 6,814 4,867 Other 1,970 767 Total accrued liabilities $ 89,980 $ 91,461

Long Term Debt (Tables)

Long Term Debt (Tables)	12 Months Ended
	Dec. 31, 2023
Debt Disclosure [Abstract]
Schedule of Maturities of Long-Term Debt	Future minimum payments, including interest and principal, under the loans payable outstanding as of December 31, 2023 are as follows (in thousands): Period Ending December 31, 2023: Amount 2024 $ 12,802 2025 79,604 2026 53,387 $ 145,793 Less amount representing interest (24,641) Less unamortized discount (5,672) Loans payable, net of discount $ 115,480

Stock-based Compensation (Table

Stock-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Summary of stock option activity	The following table summarizes stock option activity during the year ended December 31, 2023: Shares Weighted Weighted Aggregate Outstanding at January 1, 2023 2,857,054 $ 81.78 Options granted 31,111 190.91 Options exercised (460,385) 88.83 Options cancelled (72,001) 144.24 Outstanding at December 31, 2023 2,355,779 $ 79.94 5.51 $ 359,861 Exercisable at December 31, 2023 1,774,976 $ 74.49 4.71 $ 281,400 Stock-based compensation expense during the years ended December 31, 2023, 2022 and 2021 was as follows (in thousands): Year Ended December 31, 2023 2022 2021 Stock-based compensation expense by type of award: Stock options $ 30,613 $ 31,625 $ 26,873 Restricted stock units 14,974 — — Performance-based restricted stock units 4,148 — — Total stock-based compensation expense $ 49,735 $ 31,625 $ 26,873 Effect of stock-based compensation expense by line item: Research and development $ 20,864 $ 13,876 $ 10,698 General and administrative 28,871 17,749 16,175 Total stock-based compensation expense included in net loss $ 49,735 $ 31,625 $ 26,873
Summary of restricted stock unit activity	The following table summarizes RSU activity, excluding performance-based RSUs, during the year ended December 31, 2023: Shares Weighted average grant date fair value Unvested at January 1, 2023 — $ — RSUs granted 398,600 243.81 RSUs vested (356) 299.98 RSUs forfeited (22,127) 283.05 Unvested at December 31, 2023 376,117 $ 241.45

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2023
Leases [Abstract]
Schedule of Future Minimum Payments for Operating Leases	Future minimum payments under the Company’s operating leases related to the ROU asset and lease liability as of December 31, 2023 was as follows (in thousand): Operating Leases 2024 937 2025 478 2026 446 Total minimum payments $ 1,861 Less: imputed interest (148) Present value of lease liabilities $ 1,713

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Schedule of Deferred Tax Assets and Liabilities	Temporary differences that give rise to deferred tax assets and liabilities are as follows (in thousands): For the years ended December 31, 2023 2022 2021 Deferred Tax Liabilities Unrealized gains on investments $ 117 $ — $ — Total Deferred Tax Liabilities $ 117 $ — $ — Deferred Tax Assets Charitable contributions $ 37 $ 45 $ 53 Accrued expenses 3,857 2,398 1,857 Intangibles 503 589 783 Stock compensation 33,976 27,226 24,335 Property, plant & equipment 95 106 80 Unrealized loss on investment — 8 23 Net operating losses 121,552 68,305 47,864 Capitalized R&D 175,145 137,328 112,848 R&D credit 48,074 35,103 23,799 Total deferred tax assets before valuation allowance 383,239 271,108 211,642 Valuation allowance (383,122) (271,108) (211,642) Total deferred tax assets 117 — — Net deferred tax assets $ — $ — $ —
Schedule of Effective Income Tax Rate Reconciliation	Differences between the effective income tax rate and the US statutory rate were as follows (in thousands): For the years ended December 31, 2023 2022 2021 Tax benefit at U.S. federal statutory rate $ (78,462) $ (62,023) $ (50,788) Stock based compensation (8,287) (7,844) — 162M limitation 3,183 7,996 22 Other nondeductible expenses 53 16 5 State income taxes benefit before valuation allowance, net of federal benefit (16,246) 13,090 (19,622) Increase in domestic valuation allowance 112,606 59,466 79,258 Research and development credit (12,971) (10,712) (9,002) Other adjustments 124 11 127 Income tax expense (benefit) $ — $ — $ —

Quarterly Financial Data (una_2

Quarterly Financial Data (unaudited) (Tables)	12 Months Ended
	Dec. 31, 2023
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Results of Operations	The following tables present a summary of quarterly results of operations for 2023 and 2022 (in thousands, except shares and per share data): Three months ended March 31, 2023 June 30, 2023 September 30, 2023 December 31, Revenues: Total revenues $ — $ — $ — $ — Operating expenses: Research and development 62,154 68,605 70,951 70,640 General and administrative 16,182 17,845 27,583 46,536 Total operating expenses 78,336 86,450 98,534 117,176 Loss from operations (78,336) (86,450) (98,534) (117,176) Interest income 3,776 3,551 3,298 8,953 Interest expense (2,336) (2,901) (3,504) (3,971) Other income — — — — Net loss $ (76,896) $ (85,800) $ (98,740) $ (112,194) Net loss per common share: Basic and diluted net loss per common share $ (4.23) $ (4.69) $ (5.34) $ (5.68) Basic and diluted weighted average number of common shares outstanding 18,187,924 18,310,952 18,476,414 19,760,842 Three months ended March 31, 2022 June 30, 2022 September 30, 2022 December 31, Revenues: Total revenues $ — $ — $ — $ — Operating expenses: Research and development 47,929 58,499 68,271 70,742 General and administrative 9,658 11,774 12,141 14,557 Total operating expenses 57,587 70,273 80,412 85,299 Loss from operations (57,587) (70,273) (80,412) (85,299) Interest income 69 323 717 1,076 Interest expense — (780) (1,502) (1,682) Other income — — — — Net loss $ (57,518) $ (70,730) $ (81,197) $ (85,905) Net loss per common share: Basic and diluted net loss per common share $ (3.36) $ (4.14) $ (4.75) $ (4.98) Basic and diluted weighted average number of common shares outstanding 17,103,395 17,103,395 17,103,395 17,237,517

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Marketable Securities (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Accounting Policies [Abstract]
Marketable securities, realized gain (loss)	$ 0	$ 0	$ 0

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Patents (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Accounting Policies [Abstract]
Patent expenses	$ 0.9	$ 0.5	$ 0.5

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Income Taxes (Details)	12 Months Ended
	Dec. 31, 2023
Income Taxes
Valuation allowance on deferred tax assets (as a percent)	100%

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Basic and Diluted Loss Per Common Share (Details) - shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Common stock options
Anti-dilutive securities
Antidilutive securities excluded from computation of earnings per share (in shares)	2,355,779	2,857,054	2,301,574
Restricted stock units
Anti-dilutive securities
Antidilutive securities excluded from computation of earnings per share (in shares)	376,117	0	0
Performance-based restricted stock units
Anti-dilutive securities
Antidilutive securities excluded from computation of earnings per share (in shares)	150,000	0	0
Preferred stock
Anti-dilutive securities
Antidilutive securities excluded from computation of earnings per share (in shares)	2,369,797	2,369,797	1,969,797
Warrants
Anti-dilutive securities
Antidilutive securities excluded from computation of earnings per share (in shares)	2,067,552	14,899	0

Liquidity and Uncertainties (De

Liquidity and Uncertainties (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Liquidity and Uncertainties
Net loss	$ (112,194)	$ (98,740)	$ (85,800)	$ (76,896)	$ (85,905)	$ (81,197)	$ (70,730)	$ (57,518)	$ (373,630)	$ (295,350)	$ (241,846)
Accumulated deficit	$ (1,336,290)				$ (962,660)				$ (1,336,290)	$ (962,660)

Cash, Cash Equivalents and Ma_3

Cash, Cash Equivalents and Marketable Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Cash, Cash Equivalents and Marketable Securities
Cash and cash equivalents	$ 99,915	$ 331,549
Marketable securities:
Unrealized gains	476	7
Unrealized losses	(8)	(39)
Cost	633,663	358,806
Fair value	634,131	358,774
Corporate debt securities due within 1 year of date of purchase
Marketable securities:
Cost	382,028	27,257
Unrealized gains	195	7
Unrealized losses	(7)	(39)
Fair value	382,216	27,225
US government and government sponsored entities due within 1 year of date of purchase (Level 2)
Marketable securities:
Cost	150,743
Unrealized gains	280
Unrealized losses	(1)
Fair value	151,022
Cash
Cash, Cash Equivalents and Marketable Securities
Cash and cash equivalents	2,729	15,100
Money market funds
Cash, Cash Equivalents and Marketable Securities
Cash and cash equivalents	$ 78,555	$ 316,449

Accrued Liabilities (Details)

Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Accrued Liabilities, Current [Abstract]
Contract research organization costs	$ 50,737	$ 53,119
Other clinical study related costs	3,724	6,582
Manufacturing and drug supply	9,705	11,262
Compensation and benefits	17,030	14,864
Professional fees	6,814	4,867
Other	1,970	767
Total accrued liabilities	$ 89,980	$ 91,461

Long Term Debt - Narrative (Det

Long Term Debt - Narrative (Details) $ in Thousands		1 Months Ended
	Feb. 03, 2023 USD ($)	Sep. 30, 2023 USD ($) shares	Jun. 30, 2023 USD ($)	May 31, 2022 USD ($) withdrawal	Dec. 31, 2023 USD ($)	Jan. 01, 2023 USD ($)	May 01, 2022 USD ($) shares
Debt Instrument [Line Items]
Number of securities called by warrants (in shares) | shares		4,555					14,899
Warrants and rights outstanding		$ 900					$ 600
Long-term debt					$ 115,480
Line of Credit | Secured Debt
Debt Instrument [Line Items]
Term charges on aggregate principal amount, percentage				5.35%
Loan Facility | Line of Credit | Secured Debt
Debt Instrument [Line Items]
Debt instrument, face amount				$ 250,000
Line of credit facility, number of withdrawals upon milestone achievements | withdrawal				2
Long term debt floor interest rate percentage				7.45%
Accrued interest payments, term							36 months
Minimum liquidity covenant						$ 35,000
Long-term debt					$ 115,000
Line of credit facility, interest rate					10.95%
Loan Facility | Variable Rate Component One | Prime Rate | Line of Credit | Secured Debt
Debt Instrument [Line Items]
Basis spread on variable rate	2.45%
Loan Facility | Variable Rate Component Two | Prime Rate | Line of Credit | Secured Debt
Debt Instrument [Line Items]
Basis spread on variable rate	8.25%
Loan Facility, Tranche 1 | Line of Credit | Secured Debt
Debt Instrument [Line Items]
Proceeds from issuance of debt				$ 50,000
Loan Facility, Tranches 2 and 3 | Line of Credit | Secured Debt
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity				125,000
Loan Facility, Tranche 2 | Line of Credit | Secured Debt
Debt Instrument [Line Items]
Proceeds from issuance of debt	$ 35,000	$ 15,000	$ 15,000
Line of credit facility, maximum borrowing capacity	65,000
Line of credit facility, increase (decrease)			15,000
Line of credit facility, increase In maximum borrowing capacity	15,000
Loan Facility, Tranche 3 | Line of Credit | Secured Debt
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity			$ 75,000
Loan Facility, Tranche 4 | Line of Credit | Secured Debt
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	60,000			$ 75,000
Line of credit facility, decrease In maximum borrowing capacity	$ 15,000

Long Term Debt - Schedule of Ma

Long Term Debt - Schedule of Maturities of Long-Term Debt (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($)
Debt Disclosure [Abstract]
2024	$ 12,802
2025	79,604
2026	53,387
Long-term debt, gross	115,480
Less amount representing interest	(24,641)
Less unamortized discount	(5,672)
Loans payable, net of discount	$ 145,793

Stockholders' Equity - Common S

Stockholders' Equity - Common Stock (Details)	12 Months Ended
	Dec. 31, 2023 vote
Equity [Abstract]
Number of votes per share that common stockholders are entitled to receive	1

Stockholders' Equity - Preferre

Stockholders' Equity - Preferred Stock (Details)	12 Months Ended
	Dec. 31, 2023 vote $ / shares shares	Dec. 31, 2022 $ / shares
Stockholders' Equity (Deficit)
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Convertible Series A and B Preferred Stock
Stockholders' Equity (Deficit)
Preferred stock, par value (in dollars per share)	$ 0.0001
Preferred stock conversion ratio (in shares) | shares	1
Preferred shares number voting rights | vote	0

Stockholders' Equity - 2023 Pub

Stockholders' Equity - 2023 Public Offering (Details) $ / shares in Units, $ in Millions		1 Months Ended		3 Months Ended	12 Months Ended			24 Months Ended
	Sep. 28, 2023 USD ($) $ / shares shares	Oct. 31, 2023 USD ($)	Dec. 31, 2022 USD ($) shares	Dec. 31, 2023 shares	Dec. 31, 2023 USD ($) shares	Dec. 31, 2022 shares	Dec. 31, 2021 shares	Dec. 31, 2022 USD ($) shares	Sep. 30, 2023 shares	May 01, 2022 shares
Subsidiary, Sale of Stock [Line Items]
Number of securities called by warrants (in shares) | shares									4,555	14,899
Pre-Funded Warrants
Subsidiary, Sale of Stock [Line Items]
Sale of stock, minimum required percentage of ownership after transaction	0.0999
Sale of stock, maximum required percentage of ownership after transaction	0.1999
Option to increase or decrease ownership percentage, term	61 days
Public Stock Offering
Subsidiary, Sale of Stock [Line Items]
Sale of stock, number of shares issued in transaction (in shares) | shares	1,248,098		738,900	0	98,101	738,900	497,043	1,235,943
Sale of stock, price per share (in dollars per share) | $ / shares	$ 151.69
Proceeds from issuance of common stock, gross | $	$ 500		$ 159.1		$ 25.2			$ 199.9
Sale of stock, consideration received on transaction | $		$ 472
Public Stock Offering | Pre-Funded Warrants
Subsidiary, Sale of Stock [Line Items]
Number of securities called by warrants (in shares) | shares	2,048,098
Exercise price of warrants (in dollars per share) | $ / shares	$ 151.6899
Stock price discount per common share (in dollars per share) | $ / shares	$ 0.0001

Stockholders' Equity - December

Stockholders' Equity - December 2022 Registered Offering (Details) - 2022 Registered Direct Offering $ / shares in Units, $ in Millions	1 Months Ended
	Dec. 23, 2022 USD ($) $ / shares shares
Stockholders' Equity (Deficit)
Proceeds from issuance of common stock, gross | $	$ 100
Sale of stock, consideration received on transaction | $	$ 99.5
Common stock
Stockholders' Equity (Deficit)
Sale of stock, number of shares issued in transaction (in shares) | shares	44,444
Sale of stock, price per share (in dollars per share) | $ / shares	$ 225
Series B Preferred Stock
Stockholders' Equity (Deficit)
Sale of stock, number of shares issued in transaction (in shares) | shares	400,000
Sale of stock, price per share (in dollars per share) | $ / shares	$ 225

Stockholders' Equity - At The M

Stockholders' Equity - At The Market Issuances (Details) - USD ($)		1 Months Ended			3 Months Ended	12 Months Ended				24 Months Ended
	Sep. 28, 2023	May 31, 2023	Dec. 31, 2022	Nov. 30, 2020	Dec. 31, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2022
Public Stock Offering
Stockholders' Equity (Deficit)
Sale of stock, number of shares issued in transaction (in shares)	1,248,098		738,900		0	98,101	738,900	497,043		1,235,943
Proceeds from issuance of common stock, gross	$ 500,000,000		$ 159,100,000			$ 25,200,000				$ 199,900,000
Proceeds from issuance of common stock, net			$ 155,900,000			24,500,000				$ 195,800,000
Common stock reserved for future issuance amount					$ 174,800,000	$ 174,800,000
2020 Sales Agreement
Stockholders' Equity (Deficit)
Sale of stock, number of shares issued in transaction (in shares)						1,126,733		1,087,126	39,607
Proceeds from issuance of common stock, gross						$ 137,400,000
Proceeds from issuance of common stock, net						134,800,000
2021 Sales Agreement
Stockholders' Equity (Deficit)
Common stock reserved for future issuance amount					$ 0	0
Cowen & Co. LLC | Maximum | 2020 Sales Agreement
Stockholders' Equity (Deficit)
Maximum aggregate offering price				$ 200,000,000
Cowen & Co. LLC | Maximum | 2021 Sales Agreement
Stockholders' Equity (Deficit)
Maximum aggregate offering price						$ 200,000,000
Cowen & Co. LLC | Maximum | 2023 Sales Agreement Amendment
Stockholders' Equity (Deficit)
Maximum aggregate offering price		$ 200,000,000

Stock-based Compensation - Narr

Stock-based Compensation - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	12 Months Ended
	Sep. 30, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Unrecognized stock-based compensation expense
Stock options, restricted stock and performance stock units convertible, shares issuable (in shares)		2,881,896
Options granted (in shares)		31,111
Inducement Plan 2023
Unrecognized stock-based compensation expense
Shares available for future issuance (in shares)		193,392
Common stock reserved for future issuance (in shares)	500,000
Maximum | Stock Plan 2015
Unrecognized stock-based compensation expense
Expiration period		10 years
Maximum | Inducement Plan 2023
Unrecognized stock-based compensation expense
Expiration period	10 years
Common stock options
Unrecognized stock-based compensation expense
Proceeds resulting from exercise of stock options		$ 34	$ 9	$ 1
Total intrinsic value of options exercised		$ 70.4	$ 47.3	$ 0.1
Weighted-average grant date fair value of options (in dollars per share)		$ 149.15	$ 54.68	$ 73.29
Unrecognized stock compensation expense		$ 118.2
Weighted average remaining period (in years)		2 years 7 months 28 days
Common stock options | Stock Plan 2015
Unrecognized stock-based compensation expense
Shares available for future issuance (in shares)		711,054
Performance-based restricted stock units
Unrecognized stock-based compensation expense
Equity instruments other than options, outstanding (in shares)		150,000
Equity instruments other than options, weighted average grant date fair value (in dollars per share)		$ 146.37
Options granted (in shares)		50,000

Stock-based Compensation - Stoc

Stock-based Compensation - Stock Option Activity (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) $ / shares shares
Shares
Beginning balance (in shares) | shares	2,857,054
Options granted (in shares) | shares	31,111
Options exercised (in shares) | shares	(460,385)
Options cancelled (in shares) | shares	(72,001)
Ending balance (in shares) | shares	2,355,779
Exercisable at the end of the year (in shares) | shares	1,774,976
Weighted average exercise price
Outstanding at the beginning of the year (in dollars per share) | $ / shares	$ 81.78
Options granted (in dollars per share) | $ / shares	190.91
Options exercised (in dollars per share) | $ / shares	88.83
Options cancelled (in dollars per share) | $ / shares	144.24
Outstanding at the end of the year (in dollars per share) | $ / shares	79.94
Exercisable at the end of the year (in dollars per share) | $ / shares	$ 74.49
Weighted average remaining contractual life (years)
Outstanding at the end of the year	5 years 6 months 3 days
Exercisable at the end of the year	4 years 8 months 15 days
Aggregate intrinsic value (in thousands)
Outstanding at the end of the year | $	$ 359,861
Exercisable at the end of the year | $	$ 281,400

Stock-based Compensation - Rest

Stock-based Compensation - Restricted Stock Units (Details) - Restricted stock units	12 Months Ended
	Dec. 31, 2023 $ / shares shares
Shares
Unvested, beginning balance (in shares) | shares	0
Granted (in shares) | shares	398,600
Vested (in shares) | shares	(356)
Forfeited (in shares) | shares	(22,127)
Unvested, ending balance (in shares) | shares	376,117
Weighted average grant date fair value
Unvested, beginning balance (in USD per share) | $ / shares	$ 0
Granted (in USD per share) | $ / shares	243.81
Vested (in USD per share) | $ / shares	299.98
Forfeited (in USD per share) | $ / shares	283.05
Unvested, ending balance (in USD per share) | $ / shares	$ 241.45

Stock-based Compensation - Expe

Stock-based Compensation - Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Stock-based compensation expense	$ 49,735	$ 31,625	$ 26,873
Research and development
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Stock-based compensation expense	20,864	13,876	10,698
General and administrative
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Stock-based compensation expense	28,871	17,749	16,175
Common stock options
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Stock-based compensation expense	30,613	31,625	26,873
Restricted stock units
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Stock-based compensation expense	14,974	0	0
Performance-based restricted stock units
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Stock-based compensation expense	$ 4,148	$ 0	$ 0

Leases - Narrative (Details)

Leases - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Leases [Abstract]
Obtaining a right-of-use asset in exchange for a lease liability	$ 1,628	$ 583	$ 376
Weighted average, operating lease term	2 years 10 months 24 days
Weighted average, operating discount rate	10.95%
Operating lease payments	$ 1,100	700
Operating lease costs	$ 1,100	$ 800

Leases - Minimum Payments for O

Leases - Minimum Payments for Operating Leases (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Operating Leases
2024	$ 937
2025	478
2026	446
Total minimum payments	1,861
Less: imputed interest	(148)
Present value of lease liabilities	$ 1,713

Commitments and Contingencies (

Commitments and Contingencies (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Commitments and Contingencies
Revenues	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0
Obtaining a right-of-use asset in exchange for a lease liability									$ 1,628,000	$ 583,000	$ 376,000
Research, Development and Commercialization Agreement | Hoffmann-La Roche ("Roche")
Commitments and Contingencies
Remainder of future milestone payments												$ 8,000,000

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details)	12 Months Ended
	Dec. 31, 2023 USD ($)
Income Taxes
Research and development tax credit carryforwards	$ 46,100,000
Increase in valuation allowance	112,000,000
Liability for uncertain tax positions	0
Income tax related interest and penalties	0
Federal
Income Taxes
Operating loss carryforwards	489,000,000
Federal | Expire In 2037
Income Taxes
Operating loss carryforwards	40,400,000
State
Income Taxes
Operating loss carryforwards	$ 477,600,000

Income Taxes - Deferred Tax Ass

Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Deferred Tax Liabilities
Unrealized gains on investments	$ 117	$ 0	$ 0
Total Deferred Tax Liabilities	117	0	0
Deferred Tax Assets
Charitable contributions	37	45	53
Accrued expenses	3,857	2,398	1,857
Intangibles	503	589	783
Stock compensation	33,976	27,226	24,335
Property, plant & equipment	95	106	80
Unrealized loss on investment	0	8	23
Net operating losses	121,552	68,305	47,864
Capitalized R&D	175,145	137,328	112,848
R&D credit	48,074	35,103	23,799
Total deferred tax assets before valuation allowance	383,239	271,108	211,642
Valuation allowance	(383,122)	(271,108)	(211,642)
Total deferred tax assets	117	0	0
Net deferred tax assets	$ 0	$ 0	$ 0

Income Taxes - Effective Income

Income Taxes - Effective Income Tax Rate (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Tax benefit at U.S. federal statutory rate	$ (78,462)	$ (62,023)	$ (50,788)
Stock based compensation	(8,287)	(7,844)	0
162M limitation	3,183	7,996	22
Other nondeductible expenses	53	16	5
State income taxes benefit before valuation allowance, net of federal benefit	(16,246)	13,090	(19,622)
Increase in domestic valuation allowance	112,606	59,466	79,258
Research and development credit	(12,971)	(10,712)	(9,002)
Other adjustments	124	11	127
Income tax expense (benefit)	$ 0	$ 0	$ 0

Quarterly Financial Data (una_3

Quarterly Financial Data (unaudited) (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenues:
Total revenues	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0
Operating expenses:
Research and development	70,640,000	70,951,000	68,605,000	62,154,000	70,742,000	68,271,000	58,499,000	47,929,000	272,350,000	245,441,000	205,164,000
General and administrative	46,536,000	27,583,000	17,845,000	16,182,000	14,557,000	12,141,000	11,774,000	9,658,000	108,146,000	48,130,000	37,318,000
Total operating expenses	117,176,000	98,534,000	86,450,000	78,336,000	85,299,000	80,412,000	70,273,000	57,587,000	380,496,000	293,571,000	242,482,000
Loss from operations	(117,176,000)	(98,534,000)	(86,450,000)	(78,336,000)	(85,299,000)	(80,412,000)	(70,273,000)	(57,587,000)	(380,496,000)	(293,571,000)	(242,482,000)
Interest income	8,953,000	3,298,000	3,551,000	3,776,000	1,076,000	717,000	323,000	69,000	19,578,000	2,185,000	363,000
Interest expense	(3,971,000)	(3,504,000)	(2,901,000)	(2,336,000)	(1,682,000)	(1,502,000)	(780,000)	0	(12,712,000)	(3,964,000)	0
Other income	0	0	0	0	0	0	0	0	0	0	273,000
Net loss	$ (112,194,000)	$ (98,740,000)	$ (85,800,000)	$ (76,896,000)	$ (85,905,000)	$ (81,197,000)	$ (70,730,000)	$ (57,518,000)	$ (373,630,000)	$ (295,350,000)	$ (241,846,000)
Net loss per common share:
Basic net loss per common share (in dollars per share)	$ (5.68)	$ (5.34)	$ (4.69)	$ (4.23)	$ (4.98)	$ (4.75)	$ (4.14)	$ (3.36)	$ (19.99)	$ (17.23)	$ (14.63)
Diluted net loss per common share (in dollars per share)	$ (5.68)	$ (5.34)	$ (4.69)	$ (4.23)	$ (4.98)	$ (4.75)	$ (4.14)	$ (3.36)	$ (19.99)	$ (17.23)	$ (14.63)
Basic weighted average number of common shares outstanding (in shares)	19,760,842	18,476,414	18,310,952	18,187,924	17,237,517	17,103,395	17,103,395	17,103,395	18,687,774	17,137,201	16,535,188
Diluted weighted average number of common shares outstanding (in shares)	19,760,842	18,476,414	18,310,952	18,187,924	17,237,517	17,103,395	17,103,395	17,103,395	18,687,774	17,137,201	16,535,188