Zentalis Pharmaceuticals (ZNTL) 10-K 24 Feb 22 2021 FY Annual report Financial data

Cover

Cover - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Feb. 22, 2022	Jun. 30, 2021
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2021
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-39263
Entity Registrant Name	Zentalis Pharmaceuticals, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	82-3607803
Entity Address, Address Line One	1359 Broadway
Entity Address, Address Line Two	Suite 1710
Entity Address, City or Town	New York,
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10018
City Area Code	212
Local Phone Number	433-3791
Title of 12(b) Security	Common stock,$0.001 par value per share
Trading Symbol	ZNTL
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
Entity Shell Company	false
Entity Public Float			$ 1,760
Entity Common Stock, Shares Outstanding (in shares)		45,562,783
Documents Incorporated by Reference	Portions of the registrant's definitive Proxy Statement relating to its 2022 Annual Meeting of Stockholders to be filed with the SEC within 120 days after the end of the fiscal year ended December 31, 2021 are incorporated herein by reference in Part III.
Entity Central Index Key	0001725160
Amendment Flag	false
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2021

Audit Information

Audit Information	12 Months Ended
	Dec. 31, 2021
Auditor Information [Abstract]
Auditor Firm ID	42
Auditor Name	Ernst & Young LLP
Auditor Location	San Diego, California

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets
Cash and cash equivalents	$ 59,714	$ 54,951
Marketable securities, available for sale	280,173	283,554
Accounts receivable from government grants, net	4	417
Prepaid expenses and other current assets	10,636	6,182
Restricted cash	243	0
Total current assets	350,770	345,104
Property and equipment, net	8,148	1,099
Operating lease right-of-use assets	44,691	2,520
Prepaid expenses and other assets	7,040	2,976
Goodwill	3,736	3,736
In-process research and development	0	8,800
Investment in Zentera	37,495	0
Restricted cash	2,627	1,320
Total assets	454,507	365,555
Current liabilities
Accounts payable	11,590	8,661
Accrued expenses	32,354	19,940
Total current liabilities	43,944	28,601
Deferred tax liability	1,622	2,480
Long-term lease liability	44,459	1,097
Total liabilities	90,025	32,178
Commitments and contingencies (see Note 11)
EQUITY
Preferred stock, $0.001 par value; 10,000,000 shares authorized, no shares issued and outstanding at December 31, 2021 and 2020	0	0
Common stock, $0.001 par value; 250,000,000 shares authorized; 45,490,764 and 41,040,286 shares issued and outstanding at December 31, 2021 and 2020, respectively	45	41
Additional paid-in capital	723,593	509,339
Accumulated other comprehensive income (loss)	(125)	36
Accumulated deficit	(359,559)	(200,834)
Total stockholders' equity	363,954	308,582
Noncontrolling interests	528	24,795
Total equity	364,482	333,377
Total liabilities and stockholders' equity	$ 454,507	$ 365,555

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	250,000,000	250,000,000
Common stock issued (in shares)	45,490,764	41,040,286
Common stock outstanding (in shares)	45,490,764	41,040,286

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating Expenses
Research and development	$ 38,439	$ 53,998	$ 44,770	$ 38,394	$ 29,521	$ 24,670	$ 17,452	$ 13,258	$ 175,601	$ 84,901	$ 38,386
General and administrative	9,754	8,872	10,362	11,953	10,724	10,097	9,924	3,141	40,941	33,886	8,459
Total operating expenses	48,193	62,870	55,132	50,347	40,245	34,767	27,376	16,399	216,542	118,787	46,845
Loss from operations	(48,193)	(62,870)	(55,132)	(50,347)	(40,245)	(34,767)	(27,376)	(16,399)	(216,542)	(118,787)	(46,845)
Other Income (Expense)
Investment and other income, net	88	99	115	99	315	120	84	164	401	683	482
Gain on deconsolidation of Zentera	0	51,582	0	0					51,582	0	0
Net loss before income taxes	(48,105)	(11,189)	(55,017)	(50,248)	(39,930)	(34,647)	(27,292)	(16,235)	(164,559)	(118,104)	(46,363)
Income tax expense (benefit)	159	(697)	45	196	426	18	0	0	(297)	444	15
Loss on equity method investment	1,831	0	0	0					1,831	0	0
Net loss	(50,095)	(10,492)	(55,062)	(50,444)	(40,356)	(34,665)	(27,292)	(16,235)	(166,093)	(118,548)	(46,378)
Net loss attributable to noncontrolling interests	(36)	(6,301)	(488)	(543)	(53)	(110)	(435)	(109)	(7,368)	(707)	(715)
Net loss attributable to Zentalis	$ (50,059)	$ (4,191)	$ (54,574)	$ (49,901)	$ (40,303)	$ (34,555)	$ (26,857)	$ (16,126)	$ (158,725)	$ (117,841)	$ (45,663)
Net loss per common share outstanding, basic	$ (1.11)	$ (0.09)	$ (1.34)	$ (1.24)	$ (1.01)	$ (0.91)	$ (0.78)	$ (2.88)
Net loss per common share outstanding, diluted	$ (1.11)	$ (0.09)	$ (1.34)	$ (1.24)	$ (1.01)	$ (0.91)	$ (0.78)	$ (2.88)	$ 0	$ 0	$ (8.16)
Common shares/units used in computing net loss per share/Class A common unit, basic	44,976,000	44,609,000	40,738,000	40,359,000	39,936,000	37,959,000	34,353,000	5,601,000	42,688,000	28,113,000	5,597,000
Common shares/units used in computing net loss per share/Class A common unit, diluted	44,976,000	44,609,000	40,738,000	40,359,000	39,936,000	37,959,000	34,353,000	5,601,000	42,688,000	28,113,000	5,597,000
Class A Common Units
Other Income (Expense)
Net loss per common share outstanding, basic									$ 0	$ 0	$ (8.16)
Net loss per common share outstanding, diluted											(8.16)
Common Stock
Other Income (Expense)
Net loss per common share outstanding, basic									(3.72)	(4.19)	0
Net loss per common share outstanding, diluted									$ (3.72)	$ (4.19)	$ 0

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement of Comprehensive Income [Abstract]
Net loss	$ (166,093)	$ (118,548)	$ (46,378)
Other comprehensive income (loss):
Unrealized gain (loss) on marketable securities, net	(161)	36	0
Total comprehensive loss	(166,254)	(118,512)	(46,378)
Comprehensive loss attributable to noncontrolling interests	(7,368)	(707)	(715)
Comprehensive loss attributable to Zentalis	$ (158,886)	$ (117,805)	$ (45,663)

Consolidated Statements of Chan

Consolidated Statements of Changes in Convertible Preferred Units and Members’/Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	IPO	Convertible Preferred Units	Class A Common Units	Preferred StockConvertible Preferred Units	Common Stock	Common StockIPO	Common StockClass A Common Units	Common StockClass B Common Units	Additional Paid-In Capital	Additional Paid-In CapitalIPO	Accumulated Other Comprehensive Income	Accumulated Deficit	Noncontrolling Interests
Temporary equity beginning balance (in shares) at Dec. 31, 2018			0
Temporary equity, beginning balance at Dec. 31, 2018			$ 0
Increase (Decrease) in Temporary Equity [Roll Forward]
Issuance of Series C convertible preferred units at $17.50 per unit net of issuance costs (in shares)			4,847,000
Issuance of Series C convertible preferred units at $17.50 per unit net of issuance costs			$ 81,876
Reclassification of convertible preferred units for contingent liquidation features not within the Company's control (in shares)			5,103,000
Reclassification of convertible preferred units for contingent liquidation features not within the Company's control			$ 59,830
Temporary equity ending balance (in shares) at Dec. 31, 2019			9,950,000
Temporary equity, ending balance at Dec. 31, 2019			$ 141,706
Beginning balance (in shares) at Dec. 31, 2018					5,103,000	0
Beginning balance at Dec. 31, 2018	$ 32,306				$ 59,830	$ 0				$ 0		$ 0	$ (37,330)	$ 7,536
Common units, beginning balance (in shares) at Dec. 31, 2018								5,594,000	1,612,000
Common units, beginning balance at Dec. 31, 2018								$ 672	$ 1,598
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reclassification of convertible preferred units for contingent liquidation features not within the Company's control (in shares)					(5,103,000)
Reclassification of convertible preferred units for contingent liquidation features not within the Company's control	59,830				$ (59,830)
Stocks issued (in shares)									1,059,000
Share-based compensation expenses (in shares)								7,000
Share-based compensation expenses	617							$ 37	$ 580
Net loss attributable to noncontrolling interest	(715)													(715)
Net loss attributable to Zentalis	(45,663)												(45,663)
Ending balance (in shares) at Dec. 31, 2019					0	0
Ending balance at Dec. 31, 2019	(73,285)				$ 0	$ 0				0		0	(82,993)	6,821
Common units, ending balance (in shares) at Dec. 31, 2019								5,601,000	2,671,000
Common units, ending balance at Dec. 31, 2019								$ 709	$ 2,178
Increase (Decrease) in Temporary Equity [Roll Forward]
Issuance of Series C convertible preferred units at $17.50 per unit net of issuance costs (in shares)			867,000
Issuance of Series C convertible preferred units at $17.50 per unit net of issuance costs			$ 14,228
Conversion of convertible preferred units to common stock (in shares)			(10,817,000)			(15,011,000)
Conversion of convertible preferred units to common stock	$ 155,934		$ (155,934)			$ 15				155,919
Temporary equity ending balance (in shares) at Dec. 31, 2020	0		0
Temporary equity, ending balance at Dec. 31, 2020			$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cancellation of profit interest awards, net (in shares)									(64,000)
Stocks issued (in shares)				0		4,744,000	10,589,000
Stock issued, value	$ 155,305	$ 172,365				$ 5	$ 11			155,300	$ 172,354
Contributions from noncontrolling interest owners	18,424													18,424
Share-based compensation expenses	23,146								$ 329	22,817
Conversion of convertible preferred units to common stock (in shares)			10,817,000			15,011,000
Conversion of convertible preferred units to common stock	155,934		$ (155,934)			$ 15				155,919
Conversion of common and incentive units to common and restricted stock (in shares)						(10,278,000)		(5,601,000)	(2,607,000)
Conversion of common and incentive units to common and restricted stock	0					$ 10		$ (709)	$ (2,507)	3,206
Issuance and withholding of common stock in connection with restricted stock unit vesting, net (in shares)						426,000
Cancellation of restricted stock awards (in shares)						(8,000)
Other comprehensive income (loss)	36											36
Net loss attributable to noncontrolling interest	(707)									(257)				(450)
Net loss attributable to Zentalis	(117,841)												(117,841)
Ending balance (in shares) at Dec. 31, 2020					0	41,040,000
Ending balance at Dec. 31, 2020	$ 333,377				$ 0	$ 41				509,339		36	(200,834)	24,795
Common units, ending balance (in shares) at Dec. 31, 2020								0	0
Common units, ending balance at Dec. 31, 2020						$ 41		$ 0	$ 0
Temporary equity ending balance (in shares) at Dec. 31, 2021	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stocks issued (in shares)				0		3,691,000
Stock issued, value	$ 171,973					$ 4				171,969
Share-based compensation expenses	35,737									35,737
Issuance and withholding of common stock in connection with restricted stock unit vesting, net (in shares)						516,831
Issuance and withholding of common stock in connection with restricted stock unit vesting, net	(1,146)									(1,146)
Cancellation of restricted stock awards (in shares)						(4,000)
Other comprehensive income (loss)	(161)											(161)
Net loss attributable to noncontrolling interest	(7,368)													(7,368)
Net loss attributable to Zentalis	(158,725)												(158,725)
Deconsolidation event	$ (16,899)													(16,899)
Issuance of common stock upon exercise of options (in shares)	232,684					232,000
Issuance of common stock upon exercise of options	$ 7,149									7,149
Issuance of common stock under employee stock purchase plan (in shares)						15,000
Issuance of common stock under employee stock purchase plan	545									545
Ending balance (in shares) at Dec. 31, 2021						45,491,000
Ending balance at Dec. 31, 2021	$ 364,482									$ 723,593		$ (125)	$ (359,559)	$ 528
Common units, ending balance at Dec. 31, 2021						$ 45

Consolidated Statements of Ch_2

Consolidated Statements of Changes in Convertible Preferred Units and Members’/Stockholders' Equity (Deficit) (Parenthetical)) - $ / shares	Dec. 31, 2020	Feb. 29, 2020	Dec. 31, 2019	Sep. 30, 2019
Series C Preferred Units
Par value per share (in dollars per share)	$ 17.50	$ 17.50	$ 17.50	$ 17.50

Consolidated Statements of Cash

Consolidated Statements of Cash Flows $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Operating activities:
Net loss	$ (166,093)	$ (118,548)	$ (46,378)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	544	160	111
IPR&D impairment	8,800	0	0
Recognized tax gain on IPR&D impairment	(2,462)	0	0
Gain on deconsolidation of Zentera, net of tax	(49,930)	0	0
Share-based compensation	35,737	23,146	617
Loss on disposal of equipment	15	0	0
Amortization of premiums on marketable securities, net	908	556	0
Loss on equity method investment	1,831	0	0
Deferred income taxes	0	17	0
Changes in operating assets and liabilities:
Accounts receivable	413	(277)	777
Prepaid expenses and other assets	881	(5,519)	(1,508)
Accounts payable and accrued liabilities	13,916	14,307	7,123
Operating lease right-of-use assets and liabilities, net	1,347	(667)	115
Net cash used in operating activities	(154,093)	(86,825)	(39,143)
Investing activities:
Purchases of marketable securities	(363,508)	(400,984)	0
Proceeds from maturities of marketable securities	365,820	116,910	0
Deconsolidation of Zentera cash	(14,320)	0	0
Purchases of property and equipment	(6,107)	(758)	(352)
Net cash used in investing activities	(18,115)	(284,832)	(352)
Financing activities:
Proceeds from issuance of common stock in initial public offering, net	0	172,482	0
Proceeds from issuance of common stock under equity incentive plans	7,694	0	0
Net-settlement of restricted stock unit vesting	(1,146)	0	0
Contributions from noncontrolling interest owners, net	0	18,424	0
Proceeds from issuance of common stock, net	171,973	155,305	0
Proceeds from the issuance of Series C convertible preferred units, net	0	14,228	81,876
Deferred financing costs	0	0	(46)
Net cash provided by financing activities	178,521	360,439	81,830
Net increase/(decrease) in cash, cash equivalents and restricted cash	6,313	(11,218)	42,335
Cash, cash equivalents and restricted cash at beginning of year	56,271	67,489	25,154
Cash, cash equivalents and restricted cash at end of year	62,584	56,271	67,489
Supplemental disclosure of cash flow information:
Income taxes paid	20	18	15
Supplemental disclosure of non-cash investing and financing activities:
Right-of-use assets obtained in exchange for operating lease liabilities	44,613	300	1,412
Accrued capital expenditures	1,510	0	0
Costs incurred in connection with initial public offering included in accounts payable and accrued expenses	0	0	795
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents
Cash and cash equivalents	59,714	54,951	67,246
Restricted cash, current	243	0	0
Restricted cash, non-current	2,627	1,320	243
Total cash, cash equivalents and restricted cash reported in the Consolidated Statement of Cash Flows	$ 62,584	$ 56,271	$ 67,489

Organization and Business

Organization and Business	12 Months Ended
	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Business	Organization and Business Organization Zentalis Pharmaceuticals, Inc. (“Zentalis”, “We” or the “Company”) is a clinical-stage pharmaceutical company focused on discovering and developing clinically differentiated, novel small molecule therapeutics targeting fundamental biological pathways of cancer. The Company manages its operations as a single segment for the purposes of assessing performance and making operating decisions. All of the Company’s tangible assets are held in the United States. The Company was formed and incorporated in the state of Delaware as Zeno Pharmaceuticals, Inc. on December 23, 2014. Effective November 21, 2017, Zeno Pharma, LLC was formed by the shareholders of Zeno Pharmaceuticals, Inc. On December 21, 2017, Zeno Pharmaceuticals, Inc. became a wholly owned subsidiary of Zeno Pharma, LLC. In connection with this restructuring, the rights and preferences of the Preferred Stock of Zeno Pharmaceuticals, Inc. were exchanged for preferred units with similar rights and preferences of Zeno Pharma, LLC. As part of the restructuring, the employees, consultants and board members of Zeno Pharmaceuticals, Inc. exchanged their equity grants in Zeno Pharmaceuticals, Inc. stock for Class B common units in Zeno Pharma, LLC. Additionally, existing common stockholders of Zeno Pharmaceuticals, Inc. exchanged their common stock for Class A common units in Zeno Pharma, LLC. All exchanges were made on a one-for-one basis. The restructuring was accounted for as a common control transaction. In December 2019, the Company was renamed to Zentalis Pharmaceuticals, LLC. Immediately prior to the effectiveness of the registration statement pertaining to the Company’s initial public offering (“IPO”) on April 2, 2020, the Company converted from a Delaware limited liability company into a Delaware corporation, and changed its name to Zentalis Pharmaceuticals, Inc. Pursuant to the statutory corporate conversion, all of the outstanding units of Zentalis Pharmaceuticals, LLC converted into shares of common stock of Zentalis Pharmaceuticals, Inc. based upon the value of Zentalis Pharmaceuticals, Inc. at the time of the IPO with a value implied by the price of the shares of common stock sold in the IPO. Based on the IPO price of $18.00 per share, the outstanding converted units converted into 25,288,854 shares of common stock (including 1,160,277 shares of restricted common stock). On April 7, 2020, the Company completed the IPO in which the Company issued and sold 10,557,000 shares of common stock (including 1,377,000 shares of common stock in connection with the full exercise of the underwriters’ option to purchase additional shares) at a public offering price of $18.00 per share. The Company’s aggregate gross proceeds from the sale of shares in the IPO, including the sale of shares pursuant to the full exercise of the underwriters’ option to purchase additional shares, was $190.0 million before fees and expenses of $17.6 million.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation The consolidated financial statements have been prepared in conformity with U.S. generally accepted accounting principles (“U.S. GAAP”) and include our wholly owned subsidiaries and variable interest entity (“VIE”), for which we are the primary beneficiary. All intercompany transactions and balances have been eliminated in consolidation. We evaluate our ownership, contractual and other interests in entities that are not wholly-owned to determine if these entities are VIEs, and, if so, whether we are the primary beneficiary of the VIE. In determining whether we are the primary beneficiary of a VIE and therefore required to consolidate the VIE, we apply a qualitative approach that determines whether we have both (1) the power to direct the activities of the VIE that most significantly impact the VIE’s economic performance and (2) the obligation to absorb losses of, or the rights to receive benefits from, the VIE that could potentially be significant to that VIE. We will continuously assess whether we are the primary beneficiary of a VIE, as changes to existing relationships or future transactions may result in the consolidation or deconsolidation of such VIE. During the periods presented, we have not provided any other financial or other support to our VIE that we were not contractually required to provide. Noncontrolling Interests Noncontrolling interests represent interests held by third parties in our consolidated subsidiaries. We reflect noncontrolling interest attributable to the other owners in a separate line in our consolidated statements of operations and a separate line within stockholders' equity in our consolidated balance sheets. Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in our consolidated financial statements and accompanying notes. On an ongoing basis, we evaluate our estimates and judgments, which are based on historical and anticipated results and trends and on various other assumptions that management believes to be reasonable under the circumstances. By their nature, estimates are subject to an inherent degree of uncertainty and, as such, actual results may differ from management’s estimates. Though the impact of the COVID-19 pandemic to our business and operating results presents additional uncertainty, we continue to use the best information available to inform our critical accounting estimates. Cash and Cash Equivalents Cash equivalents are comprised of short-term, highly-liquid investments with maturities of 90 days or less at the date of purchase. As of December 31, 2021 and 2020, our cash equivalents consisted of money market funds and corporate debt securities. Marketable Securities Marketable securities are investments with original maturities of more than ninety days from the date of purchase that we have the ability to liquidate to fund current operations. Accordingly, those investments with contractual maturities greater than one year from the date of purchase are classified as short-term investments on the accompanying consolidated balance sheets. Marketable securities are considered available-for-sale and are carried at fair value with unrealized gains and losses recorded in other comprehensive income (loss) and included as a separate component of stockholders' equity. The cost of marketable securities is adjusted for amortization of premiums or accretion of discounts to maturity, and such amortization or accretion is included in investment and other income, net through an allowance account. We use the specific identification method for calculating realized gains and losses on marketable securities sold. Realized gains and losses on marketable securities, if any, are included in investment and other income, net in the consolidated statements of operations. Restricted Cash Under the terms of our office leases, we are required to maintain a letter of credit as a security deposit during the term of such leases. At December 31, 2021 and 2020, restricted cash of $2.9 million and $1.3 million, respectively, was pledged as collateral for the letters of credit. Fair Value of Financial Instruments The authoritative guidance defines fair value and requires us to establish a framework for measuring fair value and disclosure about fair value measurements using a three-tier approach. These tiers include: Level 1, defined as observable inputs such as quoted prices in active markets; Level 2, defined as inputs other than quoted prices in active markets that are either directly or indirectly observable; and Level 3, defined as unobservable inputs in which little or no market data exists, therefore requiring an entity to develop its own assumptions. Our financial instruments include cash equivalents, marketable securities, accounts receivable, prepaid expenses and other assets, accounts payable and accrued expenses. Fair value estimates of these instruments are made at a specific point in time, based on relevant market information. These estimates may be subjective in nature and involve uncertainties and matters of significant judgement and therefore cannot be determined with precision. The fair value of marketable securities is determined using proprietary valuation models and analytical tools, which utilize market pricing or prices for similar instruments that are both objective and publicly available, such as matrix pricing or reported trades, benchmark yields, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities and bids and offers. The carrying amount of cash equivalents, account receivable, prepaid expenses and other assets, accounts payable and accrued expenses are generally considered to be representative of their respective values because of the short-term nature of those instruments. Concentrations of Credit Risk and Sources of Supply We are subject to credit risk from our portfolios of cash equivalents and marketable securities. We maintain our cash and cash equivalent and marketable securities balances with major commercial banks. Deposits held with the financial institutions exceed the amount of insurance provided on such deposits. We are exposed to credit risk in the event of a default by the financial institutions holding our cash and cash equivalents and marketable securities to the extent recorded on the consolidated balance sheets. We have also established guidelines to limit our exposure to credit risk by diversifying our marketable securities portfolio and placing them in investments with maturities that maintain safety and liquidity. We rely on third-party manufacturers for the supply of active pharmaceutical ingredients. Property and Equipment, Net Property and equipment are recorded at cost, less accumulated depreciation and amortization. Equipment is depreciated using the straight-line method over its estimated useful life ranging from three Leases We have entered into operating leases for real estate. We determine if an arrangement is a lease at inception and evaluate each lease agreement to determine whether the lease is an operating or finance lease. For leases where we are the lessee, right-of-use (“ROU”) assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent an obligation to make lease payments arising from the lease. Liabilities from operating leases are included in accrued expenses Impairment of Long-Lived Assets We account for long-lived assets in accordance with authoritative guidance for impairment or disposal of long-lived assets. Long-lived assets are reviewed for events or changes in circumstances, which indicate that their carrying value may not be recoverable. Goodwill Our goodwill, which has an indefinite useful life, represents the excess of the cost over the fair value of net assets acquired from its business combination. The determination of the value of goodwill and intangible assets arising from business combinations and asset acquisitions requires extensive use of accounting estimates and judgments to allocate the purchase price to the fair value of the net tangible and intangible assets acquired, including capitalized in-process research and development (“IPR&D”). Goodwill is reviewed for impairment at least annually, or more frequently if an event occurs indicating the potential for impairment. During the impairment review process, we consider qualitative factors to determine whether it is more likely than not that the fair value of the reporting unit is less than the carrying amount, including goodwill. If we determine that it is not more likely than not that the fair value of our reporting unit is less than the carrying amount, then no additional assessment is deemed necessary. Otherwise, we proceed to compare the estimated fair values of the reporting units with the carrying values, including goodwill. If the carrying amounts of the reporting units exceed the fair values, we record an impairment loss based on the difference. We completed our most recent annual evaluation for impairment for goodwill as of December 31, 2021 using the qualitative assessment and determined that no impairment existed, and no charges were recorded. Equity Method Accounting We have significant influence, but not a controlling interest, in our affiliate Zentera. From the deconsolidation of Zentera during July 2021 prospectively, this investment is accounted for using the equity method. Our share of earnings or losses of the investment entity are reported on the consolidated statement of operations, with a corresponding increase or decrease to the equity investment carried on the statement of financial position. This information is generally not received sufficiently timely for us to record our portion of earnings or loss in the current financial statements, and therefore we report our portion of earnings or loss on a one quarter lag. The maximum exposure to loss as a result of our investment in Zentera is directly associated with the carrying amount of the equity method investment on our consolidated balance sheet. Research and Development Expenses Research and development expenses include salaries and benefits, facilities and other overhead expenses, external clinical trial expenses, research-related manufacturing services, contract services and other outside expenses. Research and development expenses are charged to operating expenses as incurred when these expenditures relate to our research and development efforts and have no alternative future uses. Reimbursed research and development costs under government grant arrangements are recorded as a reduction to research and development expenses and are recognized in the period in which the related costs are incurred. We are obligated to make upfront payments upon execution of certain research and development agreements. Advance payments, including nonrefundable amounts, for goods or services that will be used or rendered for future research and development activities are deferred. Such amounts are recognized as expense as the related goods are delivered or the related services are performed, or such time when we do not expect the goods to be delivered or services to be performed. Clinical Trial Expenses We make payments in connection with our clinical trials under contracts with contract research organizations that support conducting and managing clinical trials. The financial terms of these agreements are subject to negotiation and vary from contract to contract and may result in uneven payment flows. Generally, these agreements set forth the scope of work to be performed at a fixed fee, unit price or on a time and materials basis. A portion of our obligation to make payments under these contracts depends on factors such as the successful enrollment or treatment of patients or the completion of other clinical trial milestones. Expenses related to clinical trials are accrued based on our estimates and/or representations from service providers regarding work performed, including actual level of patient enrollment, completion of patient studies and progress of the clinical trials. Other incidental costs related to patient enrollment or treatment are accrued when reasonably certain. If the amounts we are obligated to pay under our clinical trial agreements are modified (for instance, as a result of changes in the clinical trial protocol or scope of work to be performed), we adjust our accruals accordingly. Revisions to our contractual payment obligations are charged to expense in the period in which the facts that give rise to the revision become reasonably certain. Share-Based Compensation We record share-based compensation expense associated with equity instruments in accordance with the authoritative guidance for stock-based compensation. The cost of employee services received in exchange for an award of an equity instrument is measured at the grant date based on the estimated fair value of the award and is recognized as expense on a straight-line basis over the requisite service period of the award. Share-based compensation expense for an award with a performance condition is recognized when the achievement of such performance condition is determined to be probable. If the outcome of such performance condition is not determined to be probable or is not met, no compensation expense is recognized, and any previously recognized compensation expense is reversed. Forfeitures are recognized as a reduction of share-based compensation expense as they occur. Income Taxes Deferred income taxes are recognized for the tax consequences in future years of differences between the tax basis of assets and liabilities and their financial reporting amounts at each year end based on enacted tax laws and statutory tax rates applicable to the periods in which the differences are expected to affect taxable income. A provision has been made for income taxes due on taxable income and for the deferred taxes on temporary differences. Deferred tax assets and liabilities are adjusted for the effects of changes in tax laws and rates on the date of enactment. Realization of the deferred income tax asset is dependent on gathering sufficient taxable income in future years. Valuation allowances are established when necessary to reduce deferred tax assets to the amount expected to be realized. Income tax expense is the combination of the tax payable for the period and the change during the period in deferred tax assets and liabilities. We follow the accounting guidance on accounting for uncertainty in income taxes. The guidance prescribes a recognition threshold and measurement attribute criteria for the financial statement recognition and measurement of tax positions taken or expected to be taken in a tax return. For those benefits to be recognized, a tax position must be more likely than not to be sustained upon examination by taxing authorities based on the technical merits of the position. Accumulated Other Comprehensive Income Accumulated other comprehensive income is the result of unrealized gains and losses on marketable securities. Net Loss per Common Share Outstanding Basic net loss per common share outstanding is computed by dividing net loss, after adjusting for dividends, if declared, by the weighted-average number of common shares outstanding during the period. Diluted net loss per common share outstanding is computed using the weighted-average number of common shares outstanding during the period and, if dilutive, the weighted average number of potential common shares. Potential common shares consist of unvested restricted stock and common shares issuable upon the exercise of stock options. Adoption and Pending Adoption of Recent Accounting Pronouncements The following table provides a brief description of recently issued accounting standards, those adopted in the current period and those not yet adopted: Standard Description Effective Date Effect on the Financial In January 2020, the FASB issued ASU 2020-01, Investments — Equity Securities (Topic 321). This standard clarifies the interaction between accounting standards related to equity securities (ASC 321), equity method investments (ASC 323), and certain derivatives (ASC 815) January 1, 2021 As of January 1, 2021, we did not hold equity securities, equity method investments or derivatives. The impact of this new accounting guidance in 2021 did not have a material impact to our consolidated financial statements at the time of adoption. As of July 2021, we hold an equity method investment which is accounted for under ASC 323. The investment is recorded on the consolidated statement of financial position at fair value as of the date of deconsolidation. The Company’s subsequent share of earnings or losses of the investment entity are reported on the consolidated statement of operations through investment and other income, net with a corresponding increase or decrease to the equity investment.

Significant Transactions

Significant Transactions	12 Months Ended
	Dec. 31, 2021
Equity Method Investments and Joint Ventures [Abstract]
Significant Transactions	Significant Transactions Zentera Therapeutics In May 2020, we became a majority common shareholder of Zentera Therapeutics, Ltd., a Shanghai-based clinical-stage biopharmaceutical company focused on developing cancer therapeutics (“Zentera”), concurrent with its Series A convertible preferred stock offering. The financial position and results of operations of Zentera were included in our consolidated financial statements from the date of the initial investment as a result of our control of the entity and our determination that we were the primary beneficiary of Zentera. In July 2021, Zentera completed a Series B convertible preferred stock offering which diluted our investment to a position of less than majority owned. Upon review of the facts and circumstances, together with the authoritative accounting literature, we determined that while Zentera is a variable interest entity ("VIE"), consolidation of Zentera is no longer appropriate. After the July 2021 Series B convertible preferred offering in which we did not participate, our review concluded that we ceased to be the primary beneficiary of Zentera as our equity ownership was reduced and changes were made to the corporate governance of Zentera. As a result, we no longer individually have the ability to direct the activities that most significantly impact Zentera's economic performance. Beginning in July 2021, the financial position and results of operations of Zentera are no longer included in our consolidated financial statements. During the period of deconsolidation we measured the fair value of our retained investment in Zentera using the backsolve method with consideration for a lack of marketability. An equity method investment of $37.5 million is recorded on our balance sheet at December 31, 2021. A deferred tax liability of $8.0 million representing the tax impact of the unrealized gain on deconsolidation is recorded on our balance sheet at December 31, 2021. A gain of $51.6 million, measured as the difference between the fair value of our retained noncontrolling interest together with the carrying amount of the Zentera noncontrolling interest, and the carrying amount of Zentera’s assets and liabilities was recognized during the year ended December 31, 2021. The difference between the carrying amount of our investment in Zentera and our portion of the Zentera net assets was $7.1 million as of December 31, 2021. This difference is accounted for in our equity method investment analogous to in-process research and development. In May 2020, each of our subsidiaries Zeno Alpha, Inc., K-Group Alpha, Inc., Zeno Management Inc., and K-Group Beta, Inc. entered into a collaboration and royalty-bearing license agreement with Zentera, which we refer to as the “Zentera Sublicenses,” pursuant to which we collaborate with Zentera on the development and commercialization of ZN-c3, ZN-c5 and ZN-d5, respectively, in the People’s Republic of China, Macau, Hong Kong and Taiwan, which is referred to as the “Zentera Collaboration Territory.” Under each Zentera Sublicense, Zentera will lead development, and upon regulatory approval, the commercialization, of the collaboration products in the Zentera Collaboration Territory.

Business Combinations

Business Combinations	12 Months Ended
	Dec. 31, 2021
Business Combination and Asset Acquisition [Abstract]
Business Combinations	Business Combinations Kalyra Pharmaceuticals, Inc. On December 21, 2017, we acquired $4.5 million of Kalyra Pharmaceuticals, Inc.’s Series B Preferred Stock representing a 25% equity interest in Kalyra Pharmaceuticals, Inc. for purposes of entering the analgesics therapeutic research space. The acquisition price was paid entirely in cash. In accordance with the authoritative guidance, we concluded that Kalyra is a business consisting of inputs, employees, intellectual property and processes capable of producing outputs. Additionally, we have concluded that Kalyra is a variable interest entity, we are the primary beneficiary and have the power to direct the activities that most significantly affect Kalyra’s economic performance through common management and our board representation. Prior to the change of control, Zentalis and Kalyra transacted for the delivery of research and development services and support. The financial position and results of operations of Kalyra have been included in our consolidated financial statements from the date of the initial investment. Pursuant with authoritative guidance, we have recorded the identifiable assets, liabilities and noncontrolling interests in the VIE at their fair value upon initial consolidation. The identified goodwill is comprised of the workforce and expected synergies from combining the entities. During the year ended December 31, 2021, Kalyra determined that they will no longer pursue the development of Kalyra's lead product candidate and ceased the associated clinical trial. The in-process research and development costs ("IPR&D") recorded on Kalyra's balance sheet exclusively relates to this candidate. Management recorded an impairment charge of $8.8 million within the research and development expense line item on the consolidated statement of operations during the year ended December 31, 2021, which resulted in a reduction of the IPR&D asset from $8.8 million to zero. The impairment of IPR&D resulted in a reversal of the associated deferred tax liability of $2.5 million during the year ended December 31, 2021. Total assets and liabilities of Kalyra as of December 31, 2021 and 2020 are immaterial. The liabilities recognized as a result of consolidating Kalyra do not represent additional claims on our general assets. Pursuant to the authoritative guidance, the equity interest in Kalyra not owned by Zentalis is reported as a noncontrolling interest on our consolidated balance sheets. The following is a reconciliation of equity (net assets) attributable to the noncontrolling interest (in thousands): December 31, 2021 2020 Noncontrolling interest at beginning of period $ 24,795 $ 6,821 Net loss attributable to noncontrolling interest (7,368) (450) Contributions from noncontrolling interest holders of Zentera — 18,424 Deconsolidation of Zentera (16,899) — Noncontrolling interest at end of period $ 528 $ 24,795

Fair Value Measurement

Fair Value Measurement	12 Months Ended
	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurement	Fair Value Measurement Available-for-sale marketable securities consisted of the following (in thousands): December 31, 2021 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Commercial paper $ 199,321 $ 11 $ (55) $ 199,277 Corporate debt securities 10,085 — (7) 10,078 US government agencies 20,032 1 — 20,033 US Treasury securities 50,860 — (75) 50,785 $ 280,298 $ 12 $ (137) $ 280,173 As of December 31, 2021, twenty-nine of our available-for-sale debt securities with a fair market value of $174.6 million were in a gross unrealized loss position of one hundred thirty-seven thousand dollars. When evaluating an investment for impairment, we review factors such as the severity of the impairment, changes in underlying credit ratings, forecasted recovery, our intent to sell or the likelihood that we would be required to sell the investment before its anticipated recovery in market value and the probability that the scheduled cash payments will continue to be made. Based on our review of these marketable securities, we believe none of the unrealized loss is as a result of a credit loss as of December 31, 2021, because we do not intend to sell these securities, and it is not more-likely-than-not that we will be required to sell these securities before the recovery of their amortized cost basis. Contractual maturities of available-for-sale debt securities are as follows (in thousands): December 31, 2021 Estimated Fair Value Due within one year $ 258,948 After one but within five years 21,225 $ 280,173 Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants at the measurement date. Fair value should maximize the use of observable inputs and minimize the use of unobservable inputs. The Company determines the fair value of financial assets and liabilities using three levels of inputs as follows: Level 1—Inputs which include quoted prices in active markets for identical assets or liabilities at the measurement date. Level 2—Inputs (other than quoted market prices included in Level 1) that are either directly or indirectly observable, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the instrument’s anticipated life. Level 3—Unobservable inputs for assets or liabilities and include little or no market activity. A financial instrument’s categorization within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement. The following table summarizes, by major security type, our cash equivalents and available-for-sale marketable securities that are measured at fair value on a recurring basis and are categorized using the fair value hierarchy (in thousands): December 31, 2021 December 31, 2020 Level 1 Level 2 Total estimated fair value Level 1 Level 2 Total estimated fair value Cash equivalents: Money market funds $ 43,653 $ — $ 43,653 $ 24,016 $ — $ 24,016 Corporate debt securities — — — — 4,999 4,999 Total cash equivalents: 43,653 — 43,653 24,016 4,999 29,015 Available-for-sale marketable securities: Commercial paper — 199,277 199,277 — 147,388 147,388 Corporate debt securities — 10,078 10,078 — 23,571 23,571 US government agencies — 20,033 20,033 — 81,486 81,486 US Treasury securities 50,785 — 50,785 31,109 — 31,109 Total available-for-sale marketable securities: 50,785 229,388 280,173 31,109 252,445 283,554 Total assets measured at fair value $ 94,438 $ 229,388 $ 323,826 $ 55,125 $ 257,444 $ 312,569 There were no transfers between Level 1 and Level 2 of the fair value hierarchy during the year ended December 31, 2021. We had no instruments that were classified within Level 3 as of December 31, 2021 or 2020.

Prepaid Expenses and Other Asse

Prepaid Expenses and Other Assets	12 Months Ended
	Dec. 31, 2021
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid Expenses and Other Assets	Prepaid Expenses and Other Assets Prepaid expenses and other assets consisted of the following (in thousands): December 31, 2021 2020 Prepaid insurance $ 990 $ 1,021 Prepaid software licenses and maintenance 403 563 Foreign R&D credit refund 1,808 692 Prepaid research and development expenses 11,204 5,963 Interest receivable 258 478 Zentera receivable 2,373 — Other prepaid expenses 640 441 Total prepaid expenses and other current assets 17,676 9,158 Less long-term portion 7,040 2,976 Total prepaid expenses and other assets, current $ 10,636 $ 6,182

Property and Equipment, net

Property and Equipment, net	12 Months Ended
	Dec. 31, 2021
Property, Plant and Equipment [Abstract]
Property and Equipment, net	Property and Equipment, net Property and equipment, net consisted of the following (in thousands): December 31, 2021 2020 Lab equipment $ 2,057 $ 424 Leasehold improvements 4,515 49 Office equipment and furniture 2,123 405 Computer equipment 211 124 Construction in process 34 347 Subtotal 8,940 1,349 Accumulated depreciation and amortization (792) (250) Property and equipment, net $ 8,148 $ 1,099 Depreciation and amortization expense was approximately $0.5 million and $0.2 million for the years ended December 31, 2021 and 2020, respectively.

Accrued Expenses

Accrued Expenses	12 Months Ended
	Dec. 31, 2021
Payables and Accruals [Abstract]
Accrued Expenses	Accrued Expenses Accrued expenses consist of the following (in thousands): December 31, 2021 2020 Accrued research and development expenses $ 18,531 $ 11,947 Accrued employee expenses 9,250 5,649 Accrued general and administrative expenses 1,480 996 Lease liability 1,453 902 Income taxes payable 971 410 Other 669 36 Total accrued expenses $ 32,354 $ 19,940

Convertible Preferred Units

Convertible Preferred Units	12 Months Ended
	Dec. 31, 2021
Temporary Equity Disclosure [Abstract]
Convertible Preferred Units	Convertible Preferred Units Series A Convertible Preferred Units In September 2015, Zeno Pharmaceuticals, Inc. entered into a Series A Preferred Stock Purchase Agreement (the “Series A Preferred Agreement”). Under the terms of the Series A Preferred Agreement, Zeno Pharmaceuticals, Inc. issued 1,293,104 shares of Series A convertible preferred stock at $11.60 per share for gross proceeds of $15.0 million. The net proceeds of this financing were $14.9 million after issuance costs of $0.1 million. In February and March 2016, Zeno Pharmaceuticals, Inc. issued an aggregate of 286,205 additional shares of Series A convertible preferred stock at $11.60 per share for additional gross proceeds of $3.3 million. The issuance costs of this additional financing were approximately thirty-nine thousand dollars. All Series A convertible preferred stock issued and outstanding by Zeno Pharmaceuticals, Inc. was converted into Series A convertible preferred units of Zentalis Pharmaceuticals, LLC in conjunction with the corporate restructuring and merger (see Note 10). Series B Convertible Preferred Units In December 2017, Zentalis Pharmaceuticals, LLC entered into a Series B Preferred Unit Purchase Agreement (the “Series B Preferred Agreement”). Under the terms of the Series B Preferred Agreement, Zentalis Pharmaceuticals, LLC issued 2,735,320 Series B preferred units at $12.43 per unit for gross proceeds of $34.0 million. The net proceeds of this financing were $32.1 million after issuance costs of $1.9 million. In January and August 2018, Zentalis Pharmaceuticals, LLC issued an aggregate of 788,419 additional shares of Series B preferred units at $12.43 per unit for additional gross proceeds of $9.8 million. The net proceeds of this additional financing were $9.5 million after issuance costs of $0.3 million. Series C Convertible Preferred Units In September 2019, Zentalis Pharmaceuticals, LLC entered into a Series C Preferred Unit Purchase Agreement (the “Series C Preferred Agreement”). Under the terms of the Series C Preferred Agreement, Zentalis Pharmaceuticals, LLC issued 4,847,106 units of Series C convertible preferred units at $17.50 per unit for gross proceeds of $84.8 million. The net proceeds of this financing were $81.9 million after issuance costs of $2.9 million. In February 2020, Zentalis Pharmaceuticals, LLC issued 867,194 additional units of Series C preferred units under the Series C Preferred Agreement. The units were issued for $17.50 per unit for gross proceeds of $15.2 million. The net proceeds of this financing were $14.2 million after issuance costs of $1.0 million. There were no authorized, issued, and outstanding shares of convertible preferred units at December 31, 2021 and 2020. During 2019, we reclassified the convertible preferred units from members' equity to temporary equity because, in conjunction with the Series C convertible preferred units issuance, all units were now deemed to contain contingent liquidation features that are not solely within our control. During the year ended December 31, 2020, we did not adjust the carrying values of the convertible preferred units to the deemed redemption values of such units since a liquidation event was not probable. Dividends Dividends are payable if and when declared by the Board of Directors. No dividends have been declared through December 31, 2021. Conversion Each Series A preferred unit, Series B preferred unit and Series C preferred unit was convertible at the option of the holder thereof, at any time after the issuance of such unit, into Class A common units at a conversion price equal to the original purchase price (subject to anti-dilution adjustments, discussed below) which was $11.60, $12.43 and $17.50 per unit, respectively. The convertible preferred units automatically converted at the then applicable conversion rate upon the closing of a firm commitment underwritten public offering of shares of a successor corporations’ common stock, at a public offering price per share of equal to or greater than the Series C original purchase price (as adjusted for any stock splits, stock dividends, combinations or other similar recapitalization) resulting in aggregate gross cash proceeds of at least $75.0 million (a “Qualified IPO”). Additionally, the convertible preferred unit would have automatically converted into common stock, at the then applicable conversion rate, upon written consent of a majority of the then outstanding Series A, Series B and Series C convertible preferred units (voting as a separate class on an as converted to Common Unit basis). In conjunction with our IPO on April 2, 2020, which constituted a Qualified IPO, all convertible preferred units were converted into common stock. Anti-dilution protection The holders of the convertible preferred units had proportional anti-dilution protection for unit splits, unit dividends and similar recapitalizations. Subject to certain exclusions, anti-dilution price protection for additional sales of securities by us for consideration per unit less than the applicable conversion price per unit of any series of convertible preferred stock, was on a broad-based weighted average basis. Protective rights The holders of the convertible preferred units had certain protective rights, including, without limitation, regarding the authorization, alteration, redemption, or sale of Class B common units; commencement of a liquidation or deemed liquidation event; entrance into a joint venture or partnership; any incurrence of indebtedness; certain transactions that exceed a certain dollar threshold; changes to our governing documents; or the declaration of any dividends. Such actions were required to be approved by a majority of the then outstanding Series A, Series B and Series C convertible preferred unit holders (voting as a single class and on an as-converted basis), as specified in the amended and restated LLC agreement. An increase or decrease in the authorized number of Directors constituting the Board or the creation of a membership interest or equity security senior to or pari passu with Series C convertible preferred units was required to be approved by a majority of the then outstanding Series C convertible preferred Units (voting as a separate class on an as converted basis). Redemption The Series A, Series B and Series C convertible preferred units were not redeemable except in the event of certain effected deemed liquidation events. As of immediately prior to our IPO on April 2, 2020 we had classified convertible preferred units as temporary equity in accordance with authoritative guidance for the classification and measurement of potentially redeemable securities whose redemption is based upon certain change in control events outside of our control, including liquidation, sale or transfer of control of the Company. We did not adjust the carrying value of the convertible preferred units to the deemed redemption values of such units since a liquidation event was not probable. Liquidation preference In the event of the dissolution, liquidation, merger or winding up of the Company, the holders of Series C convertible preferred units were entitled to receive, on a pro rata basis in respect of each such Series C convertible preferred unit, a preference amount of $17.50 per Series C convertible unit (as adjusted for any unit splits, dividends, combinations, recapitalizations or the like). Subsequent to the payment of the Series C convertible preferred unit preferences, Series A and Series B convertible preferred units were entitled to receive, on a pro rata basis in respect of each convertible preferred unit in proportion to the relative preference amount of each preferred unit, a preference amount of $11.60 and $12.43 per unit of Series A and Series B convertible preferred units (as adjusted for any units splits, dividend, combinations, recapitalizations of the like), respectively. Subsequent to the payment of the Series C, Series A and Series B convertible preferred unit preferences, Series A, Series B and Series C convertible preferred units were entitled to receive, on an as converted to common unit pro rata basis, an amount equal to distributions made to Class A common units prior to all unit classes sharing in distributions on a pro rata basis. Thereafter, Series A, Series B and Series C convertible preferred units and Series A and Series B common units were entitled to receive the remaining assets of the Company available for distribution to its unit holders pro rata based on the number of common units held by each holder, treating for these purposes as if all units had been converted to common. Voting Rights The holders of all units other than Class B common units that were unvested were to vote together as a single class. Each holder of Series A, Series B and Series C convertible preferred units were entitled to the number of votes calculated on an as converted to Class A common unit basis.

Equity and Share-based Compensa

Equity and Share-based Compensation	12 Months Ended
	Dec. 31, 2021
Equity [Abstract]
Equity and Share-based Compensation	Equity and Share-based Compensation In November 2017, Zentalis Pharmaceuticals, LLC was formed in the state of Delaware. In conjunction with a corporate restructuring, Zeno Pharmaceuticals, Inc., a Delaware corporation formed in 2014, was acquired by the Company pursuant to a merger agreement and became a wholly owned subsidiary of the Company. Per the terms of the merger agreement, each share of Zeno Pharmaceuticals, Inc. common stock issued and outstanding immediately prior to the effective time of the merger was converted into the right to receive one Class A common unit and each share of Zeno Pharmaceuticals, Inc. Series A preferred stock issued and outstanding immediately prior to the effective date of the merger converted into the right to receive one Series A preferred unit. As of the effective time of the merger agreement, all outstanding options to purchase shares of Zeno Pharmaceuticals, Inc. common stock were cancelled and replaced with profit interest awards in the LLC. In connection with the December 2017 corporate restructuring, we amended and restated the LLC agreement, and as amended, the capital units of the Company consisted of 1,638,000 authorized Series A preferred units, 3,621,000 authorized Series B preferred units, 15,000,000 authorized Class A common units and 872,620 authorized Class B common units. Class A Common Units In conjunction with the corporate restructuring in December 2017, 5,187,554 shares of common stock issued and outstanding and 406,831 shares of common stock subject to future vesting provisions of Zeno Pharmaceuticals, Inc. were converted into an equal number of Class A common units of Zentalis Pharmaceuticals, LLC. During the years ended December 31, 2021 and 2020, zero Class A common units were issued. As of December 31, 2021 and 2020, zero Class A common units were subject to future vesting conditions. Class B Common Units In conjunction with the corporate restructuring in December 2017, 703,000 options exercisable into Zeno Pharmaceuticals, Inc. common stock were converted into an equal number of Class B common units of Zentalis Pharmaceuticals, LLC. In September 2019, the number of authorized Class B common units was increased to 3,458,522. IPO and Follow-on Offerings On April 2, 2020 and immediately prior to the effectiveness of the Company’s IPO, Zentalis Pharmaceuticals, LLC converted from a Delaware limited liability company into a Delaware corporation pursuant to a statutory conversion, and changed its name to Zentalis Pharmaceuticals, Inc. In order to consummate the corporate conversion, a certificate of conversion was filed with the Secretary of State of the State of Delaware. All of the outstanding units of Zentalis Pharmaceuticals, LLC converted into shares of common stock of Zentalis Pharmaceuticals, Inc. based upon the value of Zentalis Pharmaceuticals, Inc. at the time of the IPO with a value implied by the price of the shares of common stock sold in the IPO. No cash or fractional shares of common stock were issued in connection with the corporate conversion. Based on the IPO price of $18.00 per share of common stock, all of the outstanding units converted into an aggregate of 25,288,854 shares of common stock (including 1,160,277 shares of restricted common stock). In connection with the completion of the IPO, the board and stockholders approved the certificate of incorporation to provide for 250,000,000 authorized shares of common stock with a par value of $0.001 per share and 10,000,000 authorized shares of preferred stock with a par value of $0.001 per share. On April 7, 2020, the Company completed the IPO in which the Company issued and sold 10,557,000 shares of common stock (including 1,377,000 shares of common stock in connection with the full exercise of the underwriters’ option to purchase additional shares) at a price of $18.00 per share. The Company’s aggregate gross proceeds from the sale of shares in the IPO, including the sale of shares pursuant to the full exercise of the underwriters’ option to purchase additional shares, was $190.0 million before fees and expenses of $17.6 million. On August 3, 2020, the Company completed a follow-on offering in which the Company issued and sold 4,743,750 shares of common stock (including 618,750 shares of common stock in connection with the full exercise of the underwriters' option to purchase additional shares) at a public offering price of $35.00 per share. The Company's aggregate gross proceeds from the sale of shares in the follow-on offering, including the sale of shares pursuant to the exercise of the underwriters' option to purchase additional shares, was $166.0 million before fees and expenses of $10.8 million. On July 1, 2021, the Company completed a follow-on offering in which the Company issued and sold 3,565,000 shares of common stock (including 465,000 shares of common stock in connection with the full exercise of the underwriters’ option to purchase additional shares) at a public offering price of $48.50 per share. The Company’s aggregate gross proceeds from the sale of shares in the follow-on offering, including the sale of shares pursuant to the full exercise of the underwriters’ option to purchase additional shares, was $172.9 million before fees and expenses of $10.7 million. In May 2021, the Company entered into a sales agreement, or the Sales Agreement, with SVB Leerink LLC, or SVB Leerink, as sales agent, pursuant to which the Company may, from time to time, issue and sell common stock with an aggregate value of up to $200.0 million in “at-the-market” offerings, or the ATM, under the Company's Registration Statement on Form S-3 (File No. 333-255769) filed with the SEC on May 4, 2021. Sales of common stock, if any, pursuant to the Sales Agreement, may be made in sales deemed to be an “at the market offering” as defined in Rule 415(a) of the Securities Act, including sales made directly through the Nasdaq Global Market or any other existing trading market for the Company's common stock. From May 3, 2021 to December 31, 2021 the Company sold 125,643 shares of common stock under the Sales Agreement at a volume weighted-average price of $79.59 per share, raising aggregate gross proceeds of $10.0 million before fees and expenses of $0.3 million. Share-based Compensation In the Company’s 2017 Profit Interest Plan ("the Plan") as approved and adopted by the Board of Directors on December 21, 2017, the Company was authorized to issue up to 3,458,522 shares of Class B common units ("profit interest award units"), subject to restrictions as described in the Plan. In April 2020, the Plan was terminated and the Company’s board of directors adopted, and the Company’s stockholders approved the 2020 Incentive Award Plan ("the 2020 Plan"), which became effective upon the corporate conversion. The number of common shares available for issuance under the 2020 Plan is the sum of (1) 5,600,000 shares of common stock; plus (2) any shares forfeited from the unvested restricted shares of our common stock issued upon conversion of unvested Class B common units (up to 1,250,000 shares); plus (3) an annual increase on the first day of each fiscal year beginning with the fiscal year ending December 31, 2021 and continuing to, and including, the fiscal year ending December 31, 2030, equal to the lesser of (a) 5% of the shares of common stock outstanding on the final day of the immediately preceding calendar year and (b) such smaller number of shares as determined by our board of directors. At December 31, 2021, 4,517,677 shares were subject to outstanding awards and 1,971,266 shares were available for future grants of share-based awards. In connection with the corporate conversion, each outstanding profits interest award unit was converted into a number of shares of common stock and restricted common stock based upon the IPO price. The restricted common stock issued in respect of profits interest award units continues to be subject to vesting in accordance with the vesting schedule that was applicable to such profits interest award units. During 2021, we issued an aggregate of 232,684 shares of common stock in connection with the exercises of stock options for cash in the aggregate amount of approximately $7.2 million. We did not issue any shares of common stock in connection with grants of RSA's. We issued 516,831 shares of common stock, upon vesting of RSU's. The RSU holders surrendered 17,080 RSU's to pay for minimum withholding taxes totaling approximately $1.1 million. Total share-based compensation expense related to share based awards was comprised of the following (in thousands): Year ended December 31, 2021 2020 2019 Research and development expense $ 20,858 $ 7,296 $ 339 General and administrative expense 14,879 15,850 278 Total share-based compensation expense $ 35,737 $ 23,146 $ 617 Share-based compensation expense by type of share-based award (in thousands): Year ended December 31, 2021 2020 2019 Profits interest award units $ — $ 329 $ 617 Stock options 20,773 6,925 — RSAs and RSUs 14,643 15,892 — Employee Stock Purchase Plan 321 — — $ 35,737 $ 23,146 $ 617 Prior to the deconsolidation of Zentera during the third quarter of 2021, total share-based compensation expense includes $138 thousand of share-based compensation expense for employees, consultants and directors of Zentera, for the twelve months ended December 31, 2021, compared to $187 thousand and zero for the same period in 2020 and 2019, respectively. Total unrecognized estimated compensation cost by type of award and the weighted average requisite service period over which such expense is expected to be recognized (in thousands, unless otherwise noted): December 31, 2021 Unrecognized Remaining Stock options $ 71,753 3.0 RSAs 1,244 1.6 RSUs 6,157 2.3 Profits Interest Award Units: The following table provides a summary of the profits interest units award activity under the Plan. The amounts include profits interest units granted to both employees and non-employees: Number of Units Weighted Average Outstanding at Outstanding at December 31, 2018 1,612,311 $ 1.56 Granted 1,095,545 $ 2.73 Forfeited (37,188) $ 1.62 Outstanding at Outstanding at December 31, 2019 2,670,668 $ 2.04 Granted 70,000 $ 3.06 Cancelled upon conversion (2,740,668) $ 2.07 Outstanding at December 31, 2020 — $ — The fair value of the profits interest award units was estimated using an option pricing model with the following assumptions: Year ended December 31, 2020 2019 Members’ equity value (in thousands) $271,207 $197,041 - $271,207 Threshold amounts (in thousands) $309,824 $143,800 - $309,824 Risk-free rate 1.5% 1.5% Volatility 75.0% 75.0% Time to liquidity (in years) 1.1 1.1 - 1.8 Lack of marketability discount 26.5% 18.8% - 26.4% Grant date fair value $3.06 $1.88 - $3.06 The Black-Scholes-Merton option pricing model (“Black-Scholes model) was used to estimate the fair value of each profit interest award units on the date of grant. The members’ equity value was based on a recent enterprise valuation analysis performed. The threshold amounts were determined by the Board of Directors at the time of grant. The expected life of the profits interest award units granted during the period presented was determined based on an expected liquidation event under the plan. We applied the risk-free interest rate based on the U.S. Treasury yield in effect at the time of the grant consistent with the life of the award. The expected volatility was based on a peer group in the industry in which the Company does business consistent with the expected time to liquidity. The dividend yield was set at zero as the underlying security does not and is not expected to pay a dividend. The Finnerty model and the Asian Protective Put Model methods were used to estimate the discount for lack of marketability inherent to the awards. Stock Options: The following table summarizes option activity for the year ended December 31, 2021. The amounts include incentive units granted to both employees and non-employees: Number of Shares Weighted Average Weighted Average Remaining Contractual Term (Years) Aggregate Intrinsic Value (in thousands) Outstanding at December 31, 2020 3,121,221 $ 25.45 Granted 1,527,300 $ 50.95 Exercised (232,684) $ 30.73 Cancelled (172,355) $ 34.49 Outstanding at December 31, 2021 4,243,482 $ 33.97 8.7 $212,566 Vested and expected to vest at December 31, 2021 4,243,482 $ 33.97 8.7 $212,566 Exercisable at December 31, 2021 1,141,421 $ 24.84 8.4 $67,600 The weighted average grant date fair value of stock options granted during the years ended December 31, 2021 and 2020 was $33.27 and $16.79, respectively. The total intrinsic value of options exercised during the year ended December 31, 2021 and 2020 was approximately $8.8 million and zero, respectively. The exercise price of stock options granted is equal to the closing price of the common stock on the date of grant. The fair value of each option award is estimated on the date of grant using the Black-Scholes model. Due to the Company’s limited operating history and a lack of company specific historical and implied volatility data, the Company estimates expected volatility based on the historical volatility of a group of similar companies that are publicly traded. The historical volatility data was computed using the daily closing prices for the selected companies’ shares during the equivalent period of the calculated expected term of the stock-based awards. The Company uses the “simplified method” for estimating the expected term of employee options, whereby the expected term equals the arithmetic average of the vesting term and the original contractual term of the option (generally 10 years). The risk-free interest rate is based on the U.S. Treasury yield for a period consistent with the expected term of the option in effect at the time of the grant. The Company has not issued any dividends and does not expect to issue dividends over the life of the options. As a result, the Company has estimated the dividend yield to be zero. The fair value of the stock options granted during the year ended December 31, 2021 was determined with the following assumptions: Year ended December 31, 2021 2020 Expected volatility 73.2% - 76.6% 76.4% - 78.7% Average expected term (in years) 5.2 - 6.1 1.0 - 6.0 Risk-free interest rate 0.5% - 1.3% 0.1% - 0.5% Expected dividend yield —% —% Restricted Stock Awards: RSAs are shares of our common stock subject to forfeiture restrictions that lapse based on the awardee's continued employment or service. The shares covered by a RSA cannot be sold, pledged or otherwise disposed of until the awards vest, and any unvested shares will be forfeited following the awardee's termination of service. The following table provides a summary of the RSA activity. The amounts include incentive units granted to both employees and non-employees: Number of Shares Weighted Average Grant Date Outstanding at Outstanding at December 31, 2020 742,411 $ 3.03 Vested (376,117) $ 4.39 Forfeited (4,462) $ 3.80 Outstanding at December 31, 2021 361,832 $ 3.47 The fair value of RSAs issued upon conversion of the unvested profit interest award units was based on a Black-Scholes pricing model. The estimated fair value of the RSAs for any future grants will be based on the closing market value of our common stock on the date of grant. The total grant date fair value of RSA's vested during the years ended December 31, 2021 and 2020 was approximately $1.7 million and $1.1 million, respectively. The fair value of RSA's vested during the years ended December 31, 2021 and 2020, was approximately $21.0 million and $14.3 million, respectively. Restricted Stock Units: A RSU is a promise by us to issue a share of our common stock upon vesting of the unit. The following table provides a summary of the restricted stock unit ("RSU") activity under the 2020 Plan. The amounts include incentive units granted to both employees and non-employees: Number of Shares Weighted Average Grant Date Outstanding at December 31, 2020 674,757 $ 23.75 Granted 158,750 $ 39.82 Vested (533,911) $ 23.75 Forfeited (25,401) $ 23.75 Outstanding at December 31, 2021 274,195 $ 33.06 The estimated fair value of the RSUs was based on the closing market value of our common stock on the date of grant. The total grant date fair value of RSU's vested during the years ended December 31, 2021 and 2020 was approximately $12.7 million and $10.1 million, respectively. The fair value of RSUs vested during the years ended December 31, 2021 and 2020 was approximately $26.4 million and $21.8 million, respectively. Employee Stock Purchase Plan In April 2020, the Company’s board of directors adopted, and the Company’s stockholders approved the 2020 Employee Stock Purchase Plan (the “2020 ESPP”), which became effective upon the corporate conversion. The number of common shares initially available for issuance under the 2020 ESPP was the sum of (1) 450,000 shares of common stock; plus (2) an annual increase on the first day of each fiscal year beginning with the fiscal year ending December 31, 2021 and continuing to, and including, the fiscal year ending December 31, 2030, equal to the least of (a) 1% of the shares of common stock outstanding on the final day of the immediately preceding calendar year, (b) 1,500,000 shares and (c) such smaller number of shares as determined by our board of directors. The 2020 ESPP was amended and restated effective March 15, 2021 to provide for a share reserve of 2,000,000 shares and the elimination of the evergreen provision. The weighted average assumptions used to estimate the fair value of stock purchase rights under the employee stock purchase plan are as follows: Year ended December 31, 2021 2020 ESPP Volatility 48.2 % — Expected term (years) 0.5 — Risk free rate 0.1 % — Expected dividend yield — % — Under the terms of the ESPP, the Company’s employees may elect to have up to 20% of their compensation, up to a maximum of $21,250 per calendar year, withheld to purchase shares of the Company’s common stock for a purchase price equal to 85% of the lower of the fair market value per share (at closing) of the Company’s common stock on (i) the first trading day of a six-month offering period, or (ii) the applicable purchase date, defined as the last trading day of the six-month offering period.

Commitment and Contingencies

Commitment and Contingencies	12 Months Ended
	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Legal Contingencies From time to time, we may be involved in various disputes, including lawsuits and claims arising in the ordinary course of business, including actions with respect to intellectual property, employment and contractual matters. Any of these claims could subject us to costly legal expenses. The Company records a liability in its consolidated financial statements for these matters when a loss is known or considered probable and the amount can be reasonably estimated. The Company reviews these estimates each accounting period as additional information is known and adjusts the loss provision when appropriate. If a matter is both probable to result in a liability and the amounts of loss can be reasonably estimated, the Company estimates and discloses the possible loss or range of loss to the extent necessary to make the consolidated financial statements not misleading. If the loss is not probable or cannot be reasonably estimated, a liability is not recorded in our consolidated financial statements. While we do generally believe that we have adequate insurance to cover many different types of liabilities, our insurance carriers may deny coverage, or our policy limits may be inadequate to fully satisfy any damage awards or settlements. If this were to happen, the payment of any such awards could have a material adverse effect on our consolidated results of operations and financial position. Additionally, any such claims, whether or not successful, could damage our reputation and business. We are currently not a party to any legal proceedings. Operating Leases We entered into a non-cancellable operating lease agreement in January 2016 to lease 11,121 square feet of laboratory and office space in San Diego. In December 2018, we entered into an amendment to the lease to extend the term of the agreement through June 2022. The lease is subject to further extension or earlier termination and subject to approximately 3.0% annual increases throughout the term of the lease. We also pay a pro rata share of operating costs, including utilities, maintenance, insurance costs and real property taxes. As part of the amendment, we received incentives in the form of a base rate abatement period. This lease was terminated in January 2022, effective February 2022. In April 2019, we entered into a lease for approximately 4,800 square feet of office space in New York, New York. The lease commenced in May 2019 and continues through June 30, 2023. The lease is subject to approximately 3.0% annual increases throughout the term of the lease. We received lease incentives under the agreement, including tenant allowances and a free rent period. We also pay for various operating costs, including utilities and real property taxes. The agreement does not contain a renewal option but does contain an early termination provision. This lease was terminated in April 2021, effective December 2021. In August 2019, we entered into a sublease for approximately 2,333 square feet of office space adjacent to the existing laboratory and office space in San Diego, California. The lease commenced in October 2019 and continues through February 2022. The lease is subject to approximately 3.0% annual increases throughout the term of the lease. We also pay for various operating costs, including utilities and real property taxes. The agreement does not contain a renewal option or an early termination provision. This lease was terminated in January 2022, effective February 2022. In September 2020, we entered into a lease for approximately 117,900 square feet of laboratory and office space in San Diego. This lease was partially terminated and amended during September 2021. This amendment reduced the rentable square feet by approximately 43,200. The lease commenced in December 2021 and continues through September 2032. The lease also included access to a temporary space of 13,200 square feet of laboratory and office space in San Diego. This lease component commenced in November 2020 and continued through January 2022. The lease is subject to approximately 3.0% annual increases throughout the lease term. We also pay for various operating costs, including utilities and real property taxes. The agreement includes two options to extend the lease for a period of five years each. When we determined our lease term for our operating lease right-of-use assets and lease liabilities for these leases, we did not include the extension options for this lease. In March 2021, we entered into a lease for approximately 31,362 square feet of office space in New York, New York. The lease commenced in December 2021 and continues through November 2032. The lease is subject to one increase in per annum rent of approximately 8.1% commencing on the sixth Rent expense recorded by the Company under the leases was approximately $2.6 million and $1.1 million for the years ended December 31, 2021 and 2020, respectively. We paid approximately $1.3 million and $1.0 million of lease payments, respectively, during the years ended December 31, 2021 and 2020. The following table presents the weighted average remaining lease term and weighted average discount rates related to our operating leases as of December 31, 2021: Weighted average remaining lease term (in years) 10.7 Weighted average discount rate 9.0% Approximate annual future minimum operating lease payments as of December 31, 2021 are as follows (in thousands): Year Amount 2022 $ 3,277 2023 6,352 2024 6,498 2025 6,973 2026 7,291 Thereafter 45,622 Total minimum lease payments: 76,013 Less: imputed interest 30,101 Total operating lease liabilities 45,912 Less: current portion 1,453 Lease liability, net of current portion $ 44,459

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Income Taxes	Income TaxesZentalis Pharmaceuticals, Inc. is a corporation for tax purposes and is subject to income taxes which have been included in the consolidated financial statements. The amount of net loss before income taxes and loss on equity method investment for the years ended December 31, 2021, 2020 and 2019 is as follows (in thousands): Year ended December 31, 2021 2020 2019 U.S. net loss before income taxes $ (171,053) $ (112,827) $ (46,363) Foreign net income (loss) before income taxes 4,663 (5,277) — Net loss before income taxes and loss on equity method investment $ (166,390) $ (118,104) $ (46,363) The following table presents the current and deferred income tax provision (benefit) for federal, state and foreign income taxes (in thousands): Year ended December 31, 2021 2020 2019 Current tax provision: Federal $ — $ — $ — State 11 16 $ 15 Foreign 550 410 $ — Total current tax provision 561 426 $ 15 Deferred tax provision: Federal (120) — — State (736) — — Foreign (2) 18 — Total deferred tax provision (858) 18 — Total provision for income taxes: $ (297) $ 444 $ 15 The following table is a reconciliation of the expected tax computed at the U.S. statutory federal income tax rate to the total provision for income taxes (in thousands): Year ended December 31, 2021 2020 2019 Expected tax at 21% $ (34,941) 21.0 % $ (24,802) 21.0 % $ (9,730) 21.0 % State income tax, net of federal tax (931) 0.6 % 273 (0.3) % (3,167) 6.8 % Limited liability company loss — — % — — % 4 — % Non-deductible expenses — — % — — % 164 (0.3) % Research credits (6,938) 4.2 % (4,025) 3.4 % (1,424) 3.1 % Share-based compensation (3,307) 2.0 % (1,718) 1.5 % — — % Other 939 (0.6) % 146 (0.1) % (2) — % Section 162(m) limitations 3,982 (2.4) % 2,956 (2.5) % — — % Change in valuation allowance 40,899 (24.6) % 27,614 (23.4) % 14,170 (30.6) % Provision for income taxes $ (297) 0.2 % $ 444 (0.4) % $ 15 0.0 % Deferred income taxes as of each of the following periods reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of our net deferred tax asset or liability are as follows (in thousands): December 31, 2021 2020 Deferred tax assets Net operating loss $ 82,117 $ 45,730 Compensation 1,553 892 Share-based compensation 4,123 1,691 ASC 842 lease liability 9,740 425 Intangibles 2,004 — Accrued liabilities 675 632 Research credits 14,466 7,528 Total gross deferred tax assets 114,678 56,898 Valuation allowance (97,160) (56,261) Net deferred tax assets 17,518 637 Deferred tax liabilities Depreciable assets (1,699) (145) ASC 842 right of use asset (9,481) (502) In-process research and development — (2,463) Equity method investment (7,954) — Other (6) (7) Deferred tax liabilities (19,140) (3,117) Net deferred tax liabilities $ (1,622) $ (2,480) Realization of a portion of our deferred tax assets is dependent upon our generating sufficient taxable income in future years to obtain benefit from the reversal of temporary differences. Management considered all available evidence under existing tax law and anticipated expiration of tax statutes and determined that a valuation allowance of $97.2 million and $56.3 million was required as of December 31, 2021 and 2020, for those deferred tax assets that are not expected to provide future tax benefits. The increase in valuation allowance was primarily related to the federal and states losses incurred and tax credits generated during the period ended December 31, 2021. At December 31, 2021, we have federal and state net operating loss ("NOL") carryforwards of approximately $361.1 million and $90.4 million, respectively. The federal NOL carryforwards generated prior to January 1, 2018 begin to expire in 2033. The federal NOL carryforwards generated after 2017 of $340.2 million can be carried forward indefinitely and be available to offset up to 80% of future taxable income each year. The state NOL carryforwards begin to expire in 2033. At December 31, 2021, we have federal and state research tax credit carryforwards, net of reserves, of approximately $10.5 million and $3.9 million, respectively. The federal credit carryforwards begin to expire in 2033, and the state credit carryforwards do not expire and can be carried forward indefinitely until utilized. We have not completed a study to determine whether an ownership change per the provisions of Section 382 of the Code, as well as similar state provisions, has occurred. Utilization of our net operating loss and income tax credit carryforwards may be subject to a substantial annual limitation due to ownership changes that may have occurred or that could occur in the future. These ownership changes may limit the amount of the net operating loss and income tax credit carryover that can be utilized annually to offset future taxable income. In general, an “ownership change” as defined by Section 382 of the Code results from a transaction or series of transactions over a three-year period resulting in an ownership change of more than 50 percentage points of the outstanding stock of a company by certain stockholders. Uncertain Tax Positions In accordance with authoritative guidance, the impact of an uncertain income tax position on the income tax return must be recognized at the largest amount that is more-likely-than-not to be sustained upon audit by the relevant taxing authority. An uncertain income tax position will not be recognized if it has less than a 50% likelihood of being sustained. The following table summarized the activity related to our unrecognized tax benefits (in thousands): December 31, 2021 2020 2019 Gross unrecognized tax benefits at the beginning of the year $ 1,932 $ 1,124 $ 741 Increase related to current year tax positions 969 661 383 Increase related to prior year tax positions — 197 — Decrease related to prior year tax positions (66) (50) — Gross unrecognized tax benefits at end of the year $ 2,835 $ 1,932 $ 1,124 Included in the balance of unrecognized tax benefits at December 31, 2021 is $2.6 million that, if recognized, would not impact our income tax benefit or effective tax rate as long as our deferred tax asset remains subject to a valuation allowance. We do not expect any significant increases or decreases to our unrecognized tax benefits within the next 12 months. We recognize interest and penalties related to unrecognized tax positions within the income tax expense line in the accompanying consolidated statements of operations. There were no accrued interest and penalties associated with uncertain tax positions as of December 31, 2021 , 2020 and 2019 . The Company files federal and state income tax returns in the United States and Australia. Due to the Company's unutilized NOLs and credits, all years remain subject to income tax examination by authorities. The Company is not currently under examination by federal, state or foreign jurisdictions. In response to the COVID-19 pandemic, the Coronavirus Aid, Relief and Economic Security Act (CARES Act) was signed into law in the U.S. in March 2020. The CARES Act adjusted a number of provisions of the tax code, including the eligibility of certain deductions and the treatment of net operating losses and tax credits. The enactment of the CARES Act did not result in any material adjustments to the Company's income tax provision for the year ended December 31, 2021, or to its deferred tax assets as of December 31, 2021. California Assembly Bill 85 (AB 85), which intends to close a gap in the budget created by the COVID-19 pandemic, was signed into law by Governor Gavin Newsom on June 29, 2020. It was passed by both houses of the California state legislature on June 15, 2020. AB 85 disallows utilization of California NOL carryforwards for any taxable year beginning on or after January 1, 2020, and before January 1, 2023 for any Corporation with a net business or modified adjusted gross income of more than $1.0 million for the taxable year. The bill also limits business credit utilization to offset a maximum of $5.0 million of California tax, including the California Research Credit. California Senate Bill 113 (SB 113) was signed into law by Governor Newsom on February 9, 2022, which restores the research and development credits net operating loss deductions for tax years beginning after December 31, 2021. We do not expect any material impacts related to this tax law change.

Net Loss Per Common Share_Class

Net Loss Per Common Share/Class A Common Unit	12 Months Ended
	Dec. 31, 2021
Earnings Per Share [Abstract]
Net Loss Per Common Share/Class A Common Unit	Net Loss Per Common Share/Class A Common Unit Basic and diluted net loss per common share/Class A common unit were calculated as follows (in thousands except per share amounts): Year ended December 31, 2021 2020 2019 Numerator: Net loss attributable to Zentalis $ (158,725) $ (117,841) $ (45,663) Denominator: Weighted average number of common shares/Class A common units outstanding, basic and diluted 42,688 28,113 5,597 Net loss per common share $ (3.72) $ (4.19) $ — Net loss per Class A common unit $ (8.16) Our potential and dilutive securities, which include outstanding stock options, unvested RSAs, unvested RSUs and preferred units, have been excluded from the computation of diluted net loss per common share/Class A common unit as the effect would be anti-dilutive. We considered the impact of presenting a separate earnings per unit calculation for Class B common units. However, as earnings and losses are only allocable to Class B common units after the applicable threshold had been met, and such thresholds had not been met for earnings per unit purposes, no losses were allocated to Class B common units. The following common stock/Class A common unit equivalents have been excluded from the calculations of diluted net loss per common share/Class A common unit because their inclusion would be antidilutive (in thousands). Year ended December 31, 2021 2020 2019 Preferred units, as if converted to Class A common units — — 9,950 Incentive units - Class B common units — — 2,671 Outstanding stock options 4,243 3,121 — Unvested RSAs 361 742 — Unvested RSUs 274 675 — 4,878 4,538 12,621

Employee Savings Plan

Employee Savings Plan	12 Months Ended
	Dec. 31, 2021
Retirement Benefits [Abstract]
Employee Savings Plan	Employee Savings PlanWe have an employee savings plan pursuant to Section 401(k) of the Internal Revenue Code. All employees are eligible to participate provided that they meet the requirements of the plan. The Company began making matching contributions under the plan during 2021. The Company has recorded as expense $991.5 thousand in matching contributions for the year ended December 31, 2021.

Related Party Disclosures

Related Party Disclosures	12 Months Ended
	Dec. 31, 2021
Related Party Transactions [Abstract]
Related Party Disclosures	Related Party Disclosures Kalyra Pharmaceuticals, Inc. On December 21, 2017, we acquired 17,307,692 shares of Series B preferred stock of Kalyra Pharmaceuticals, Inc. for a per share price of twenty-six cents ($0.26) or approximately $4.5 million. The management team and stockholders of Kalyra are also stockholders of the Company. Prior to the investment, we entered into a license agreement and a master services agreement with Kalyra. The license agreement was signed and commenced on December 31, 2014 for the exclusive rights to develop and commercialize products derived from Kalyra’s technology in the initial area of oncology. The license agreement and all rights were subsequently sold from Kalyra to Recurium IP Holdings, LLC (“Recurium IP”), an entity with common ownership to Kalyra prior to the Zentalis investment. Under the agreement, we have agreed to make payments to Recurium IP based on specific milestones. In addition, the Company shall pay mid- to high-single digit percentage royalties on net product sales to Recurium IP and sublicense fees on any consideration paid to us by a sublicensor. All payments are based on Recurium Equity, LLC’s, an affiliated company of Recurium IP, equity ownership stake in us as of December 2020. The license agreement will terminate upon the later of the last expiration of the patent rights or 15 years from the date of commencement. For the years ended December 31, 2021 and 2020 , we paid $10.0 million and zero, respectively, in milestone payments to Recurium IP. The Master Services Agreement (“MSA”) was entered into in January 2015 and states that Kalyra may provide research and development services to us and that we shall reimburse such expenses on a time and materials basis based on the initial statements of work. For the years ended December 31, 2021 and 2020, we incurred an immaterial amount of expense with Kalyra that was eliminated in consolidation for research and development services provided. As of December 31, 2021 and 2020, there was no balance due to Kalyra. We entered into an Intercompany Services Agreement (“ISA”) with Kalyra in January 2018 which states that we may provide research and development services to Kalyra and that Kalyra shall reimburse such expenses on a time and materials basis. For the years ended December 31, 2021 and 2020, we provided an immaterial amount of research and development services to Kalyra that was eliminated in consolidation. As of December 31, 2021 and 2020, an immaterial amount was due from Kalyra and eliminated in consolidation. On June 1, 2020, we entered into an equipment purchase and sale agreement with Kalyra to purchase $0.4 million of equipment and related intangible assets to be used in our operations. As of December 31, 2021 and 2020, there was no balance due to Kalyra for this transaction. Tempus Kimberly Blackwell, M.D., is a member of the Company's board of directors and is also the Chief Medical Officer of Tempus Labs, Inc. ("Tempus"). The Company entered into a Master Services Agreement with Tempus in December 2020 to provide data licensing and research services. $1.0 million and zero fees were incurred for services performed by Tempus for the years ended December 31, 2021 and 2020, respectively. Zentera Anthony Y. Sun, M.D., our President and Chief Executive Officer, serves as Chief Executive Officer and a member of the board of directors of Zentera, and Kevin D. Bunker, Ph.D., our Chief Operating Officer, serves as a member of the board of directors of Zentera. Accordingly, the Company identifies Zentera as a related party. In May 2020, we entered into the Zentera Sublicenses, pursuant to which we collaborate with Zentera on the development and comm ercialization of ZN-c3, ZN-c5 and ZN-d5, respectively, in the Zentera Collaboration Territory. Under the terms of the Zentera Sublicenses, Zentera is responsible for the costs of developing the Collaboration Products in the Zentera Collaboration Territory, and we are responsible for the costs of developing the Collaboration Products outside the Zentera Collaboration Territory, provided that Zentera will reimburse us for a portion of its costs for global data management, pharmacovigilance, safety database management, and chemistry, manufacturing and controls activities with respect to each Collaboration Product. Prior to the deconsolidation of Zentera during July 2021, these costs were eliminated in consolidation. For the period subsequent to deconsolidation through December 31, 2021, the amounts incurred under this arrangement totaled $5.3 million and are presented as contra-research and development expense in the consolidated statement of operations.

Selected Quarterly Financial Da

Selected Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2021
Quarterly Financial Information Disclosure [Abstract]
Selected Quarterly Financial Data (Unaudited)	Selected Quarterly Financial Data (Unaudited) Selected quarterly financial data is as follows: Three months ended 3/31/2021 6/30/2021 9/30/2021 12/31/2021 Operating Expenses Research and development $ 38,394 $ 44,770 $ 53,998 $ 38,439 General and administrative $ 11,953 $ 10,362 $ 8,872 $ 9,754 Total operating expenses 50,347 55,132 62,870 48,193 Operating loss (50,347) (55,132) (62,870) (48,193) Other Income (Expense) Investment and other income (expense), net $ 99 $ 115 $ 99 $ 88 Gain on deconsolidation of Zentera $ — $ — $ 51,582 $ — Net loss before income taxes (50,248) (55,017) (11,189) (48,105) Income tax expense $ 196 $ 45 $ (697) $ 159 Loss on equity method investment $ — $ — $ — $ 1,831 Net loss (50,444) (55,062) (10,492) (50,095) Net loss attributable to noncontrolling interests (543) (488) (6,301) (36) Net loss attributable to Zentalis $ (49,901) $ (54,574) $ (4,191) $ (50,059) Net loss per common share outstanding, basic and diluted $ (1.24) $ (1.34) $ (0.09) $ (1.11) Common shares used in computing net loss per share, basic and diluted 40,359 40,738 44,609 44,976 Three months ended 3/31/2020 6/30/2020 9/30/2020 12/31/2020 Operating Expenses Research and development $ 13,258 $ 17,452 $ 24,670 $ 29,521 General and administrative $ 3,141 $ 9,924 $ 10,097 $ 10,724 Total operating expenses 16,399 27,376 34,767 40,245 Operating loss (16,399) (27,376) (34,767) (40,245) Other Income (Expense) Investment and other income (expense), net $ 164 $ 84 $ 120 $ 315 Net loss before income taxes (16,235) (27,292) (34,647) (39,930) Income tax expense $ — $ — $ 18 $ 426 Net loss (16,235) (27,292) (34,665) (40,356) Net loss attributable to noncontrolling interests (109) (435) (110) (53) Net loss attributable to Zentalis $ (16,126) $ (26,857) $ (34,555) $ (40,303) Net loss per common share outstanding, basic and diluted $ (0.78) $ (0.91) $ (1.01) Net loss per Class A common unit outstanding, basic and diluted $ (2.88) Common shares/units used in computing net loss per share/Class A common unit, basic and diluted 5,601 34,353 37,959 39,936

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The consolidated financial statements have been prepared in conformity with U.S. generally accepted accounting principles (“U.S. GAAP”) and include our wholly owned subsidiaries and variable interest entity (“VIE”), for which we are the primary beneficiary. All intercompany transactions and balances have been eliminated in consolidation.
Consolidation	We will continuously assess whether we are the primary beneficiary of a VIE, as changes to existing relationships or future transactions may result in the consolidation or deconsolidation of such VIE. During the periods presented, we have not provided any other financial or other support to our VIE that we were not contractually required to provide. Noncontrolling Interests Noncontrolling interests represent interests held by third parties in our consolidated subsidiaries. We reflect noncontrolling interest attributable to the other owners in a separate line in our consolidated statements of operations and a separate line within stockholders' equity in our consolidated balance sheets.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in our consolidated financial statements and accompanying notes. On an ongoing basis, we evaluate our estimates and judgments, which are based on historical and anticipated results and trends and on various other assumptions that management believes to be reasonable under the circumstances. By their nature, estimates are subject to an inherent degree of uncertainty and, as such, actual results may differ from management’s estimates.
Cash and Cash Equivalents and Restricted Cash	Cash and Cash EquivalentsCash equivalents are comprised of short-term, highly-liquid investments with maturities of 90 days or less at the date of purchase.Restricted CashUnder the terms of our office leases, we are required to maintain a letter of credit as a security deposit during the term of such leases.
Marketable Securities	Marketable SecuritiesMarketable securities are investments with original maturities of more than ninety days from the date of purchase that we have the ability to liquidate to fund current operations. Accordingly, those investments with contractual maturities greater than one year from the date of purchase are classified as short-term investments on the accompanying consolidated balance sheets. Marketable securities are considered available-for-sale and are carried at fair value with unrealized gains and losses recorded in other comprehensive income (loss) and included as a separate component of stockholders' equity. The cost of marketable securities is adjusted for amortization of premiums or accretion of discounts to maturity, and such amortization or accretion is included in investment and other income, net through an allowance account. We use the specific identification method for calculating realized gains and losses on marketable securities sold. Realized gains and losses on marketable securities, if any, are included in investment and other income, net in the consolidated statements of operations.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The authoritative guidance defines fair value and requires us to establish a framework for measuring fair value and disclosure about fair value measurements using a three-tier approach. These tiers include: Level 1, defined as observable inputs such as quoted prices in active markets; Level 2, defined as inputs other than quoted prices in active markets that are either directly or indirectly observable; and Level 3, defined as unobservable inputs in which little or no market data exists, therefore requiring an entity to develop its own assumptions. Our financial instruments include cash equivalents, marketable securities, accounts receivable, prepaid expenses and other assets, accounts payable and accrued expenses. Fair value estimates of these instruments are made at a specific point in time, based on relevant market information. These estimates may be subjective in nature and involve uncertainties and matters of significant judgement and therefore cannot be determined with precision. The fair value of marketable securities is determined using proprietary valuation models and analytical tools, which utilize market pricing or prices for similar instruments that are both objective and publicly available, such as matrix pricing or reported trades, benchmark yields, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities and bids and offers. the measurement date. Fair value should maximize the use of observable inputs and minimize the use of unobservable inputs. The Company determines the fair value of financial assets and liabilities using three levels of inputs as follows: Level 1—Inputs which include quoted prices in active markets for identical assets or liabilities at the measurement date. Level 2—Inputs (other than quoted market prices included in Level 1) that are either directly or indirectly observable, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the instrument’s anticipated life. Level 3—Unobservable inputs for assets or liabilities and include little or no market activity.
Concentrations of Credit Risk and Sources of Supply	Concentrations of Credit Risk and Sources of Supply We are subject to credit risk from our portfolios of cash equivalents and marketable securities. We maintain our cash and cash equivalent and marketable securities balances with major commercial banks. Deposits held with the financial institutions exceed the amount of insurance provided on such deposits. We are exposed to credit risk in the event of a default by the financial institutions holding our cash and cash equivalents and marketable securities to the extent recorded on the consolidated balance sheets. We have also established guidelines to limit our exposure to credit risk by diversifying our marketable securities portfolio and placing them in investments with maturities that maintain safety and liquidity. We rely on third-party manufacturers for the supply of active pharmaceutical ingredients.
Property and Equipment, Net	Property and Equipment, Net Property and equipment are recorded at cost, less accumulated depreciation and amortization. Equipment is depreciated using the straight-line method over its estimated useful life ranging from three
Leases	Leases We have entered into operating leases for real estate. We determine if an arrangement is a lease at inception and evaluate each lease agreement to determine whether the lease is an operating or finance lease. For leases where we are the lessee, right-of-use (“ROU”) assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent an obligation to make lease payments arising from the lease. Liabilities from operating leases are included in accrued expenses
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets We account for long-lived assets in accordance with authoritative guidance for impairment or disposal of long-lived assets. Long-lived assets are reviewed for events or changes in circumstances, which indicate that their carrying value may not be recoverable.
Goodwill	Goodwill Our goodwill, which has an indefinite useful life, represents the excess of the cost over the fair value of net assets acquired from its business combination. The determination of the value of goodwill and intangible assets arising from business combinations and asset acquisitions requires extensive use of accounting estimates and judgments to allocate the purchase price to the fair value of the net tangible and intangible assets acquired, including capitalized in-process research and development (“IPR&D”). Goodwill is reviewed for impairment at least annually, or more frequently if an event occurs indicating the potential for impairment. During the impairment review process, we consider qualitative factors to determine whether it is more likely than not that the fair value of the reporting unit is less than the carrying amount, including goodwill. If we determine that it is not more likely than not that the fair value of our reporting unit is less than the carrying amount, then no additional assessment is deemed necessary. Otherwise, we proceed to compare the estimated fair values of the reporting units with the carrying values, including goodwill. If the carrying amounts of the reporting units exceed the fair values, we record an impairment loss based on
Equity Method Accounting	Equity Method Accounting We have significant influence, but not a controlling interest, in our affiliate Zentera. From the deconsolidation of Zentera during July 2021 prospectively, this investment is accounted for using the equity method. Our share of earnings or losses of the investment entity are reported on the consolidated statement of operations, with a corresponding increase or decrease to the equity investment carried on the statement of financial position. This information is generally not received sufficiently timely for us to record our portion of earnings or loss in the current financial statements, and therefore we report our portion of earnings or loss on a one quarter lag. The maximum exposure to loss as a result of our investment in Zentera is directly associated with the carrying amount of the equity method investment on our consolidated balance sheet.
Research and Development Expenses	Research and Development Expenses Research and development expenses include salaries and benefits, facilities and other overhead expenses, external clinical trial expenses, research-related manufacturing services, contract services and other outside expenses. Research and development expenses are charged to operating expenses as incurred when these expenditures relate to our research and development efforts and have no alternative future uses. Reimbursed research and development costs under government grant arrangements are recorded as a reduction to research and development expenses and are recognized in the period in which the related costs are incurred. We are obligated to make upfront payments upon execution of certain research and development agreements. Advance payments, including nonrefundable amounts, for goods or services that will be used or rendered for future research and development activities are deferred. Such amounts are recognized as expense as the related goods are delivered or the related services are performed, or such time when we do not expect the goods to be delivered or services to be performed.
Clinical Trial Expenses	Clinical Trial Expenses We make payments in connection with our clinical trials under contracts with contract research organizations that support conducting and managing clinical trials. The financial terms of these agreements are subject to negotiation and vary from contract to contract and may result in uneven payment flows. Generally, these agreements set forth the scope of work to be performed at a fixed fee, unit price or on a time and materials basis. A portion of our obligation to make payments under these contracts depends on factors such as the successful enrollment or treatment of patients or the completion of other clinical trial milestones. Expenses related to clinical trials are accrued based on our estimates and/or representations from service providers regarding work performed, including actual level of patient enrollment, completion of patient studies and progress of the clinical trials. Other incidental costs related to patient enrollment or treatment are accrued when reasonably certain. If the amounts we are obligated to pay under our clinical trial agreements are modified (for instance, as a result of changes in the clinical trial protocol or scope of work to be performed), we adjust our accruals accordingly. Revisions to our contractual payment obligations are charged to expense in the period in which the facts that give rise to the revision become reasonably certain.
Share-Based Compensation	Share-Based Compensation We record share-based compensation expense associated with equity instruments in accordance with the authoritative guidance for stock-based compensation. The cost of employee services received in exchange for an award of an equity instrument is measured at the grant date based on the estimated fair value of the award and is recognized as expense on a straight-line basis over the requisite service period of the award. Share-based compensation expense for an award with a performance condition is recognized when the achievement of such performance condition is determined to be probable. If the outcome of such performance condition is not determined to be probable or is not met, no compensation expense is recognized, and any previously recognized compensation expense is reversed. Forfeitures are recognized as a reduction of share-based compensation expense as they occur.
Income Taxes	Income Taxes Deferred income taxes are recognized for the tax consequences in future years of differences between the tax basis of assets and liabilities and their financial reporting amounts at each year end based on enacted tax laws and statutory tax rates applicable to the periods in which the differences are expected to affect taxable income. A provision has been made for income taxes due on taxable income and for the deferred taxes on temporary differences. Deferred tax assets and liabilities are adjusted for the effects of changes in tax laws and rates on the date of enactment. Realization of the deferred income tax asset is dependent on gathering sufficient taxable income in future years. Valuation allowances are established when necessary to reduce deferred tax assets to the amount expected to be realized. Income tax expense is the combination of the tax payable for the period and the change during the period in deferred tax assets and liabilities. We follow the accounting guidance on accounting for uncertainty in income taxes. The guidance prescribes a recognition threshold and measurement attribute criteria for the financial statement recognition and measurement of tax positions taken or expected to be taken in a tax return. For those benefits to be recognized, a tax position must be more likely than not to be sustained upon examination by taxing authorities based on the technical merits of the position.
Accumulated Other Comprehensive Income	Accumulated Other Comprehensive Income Accumulated other comprehensive income is the result of unrealized gains and losses on marketable securities.
Net Loss per Common Share Outstanding	Net Loss per Common Share Outstanding Basic net loss per common share outstanding is computed by dividing net loss, after adjusting for dividends, if declared, by the weighted-average number of common shares outstanding during the period. Diluted net loss per common share outstanding is computed using the weighted-average number of common shares outstanding during the period and, if dilutive, the weighted average number of potential common shares. Potential common shares consist of unvested restricted stock and common shares issuable upon the exercise of stock options.
Adoption and Pending Adoption of Recent Accounting Pronouncements	Adoption and Pending Adoption of Recent Accounting Pronouncements The following table provides a brief description of recently issued accounting standards, those adopted in the current period and those not yet adopted: Standard Description Effective Date Effect on the Financial In January 2020, the FASB issued ASU 2020-01, Investments — Equity Securities (Topic 321). This standard clarifies the interaction between accounting standards related to equity securities (ASC 321), equity method investments (ASC 323), and certain derivatives (ASC 815) January 1, 2021 As of January 1, 2021, we did not hold equity securities, equity method investments or derivatives. The impact of this new accounting guidance in 2021 did not have a material impact to our consolidated financial statements at the time of adoption. As of July 2021, we hold an equity method investment which is accounted for under ASC 323. The investment is recorded on the consolidated statement of financial position at fair value as of the date of deconsolidation. The Company’s subsequent share of earnings or losses of the investment entity are reported on the consolidated statement of operations through investment and other income, net with a corresponding increase or decrease to the equity investment.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Recently issued accounting standards adopted and not yet adopted	The following table provides a brief description of recently issued accounting standards, those adopted in the current period and those not yet adopted: Standard Description Effective Date Effect on the Financial In January 2020, the FASB issued ASU 2020-01, Investments — Equity Securities (Topic 321). This standard clarifies the interaction between accounting standards related to equity securities (ASC 321), equity method investments (ASC 323), and certain derivatives (ASC 815) January 1, 2021 As of January 1, 2021, we did not hold equity securities, equity method investments or derivatives. The impact of this new accounting guidance in 2021 did not have a material impact to our consolidated financial statements at the time of adoption. As of July 2021, we hold an equity method investment which is accounted for under ASC 323. The investment is recorded on the consolidated statement of financial position at fair value as of the date of deconsolidation. The Company’s subsequent share of earnings or losses of the investment entity are reported on the consolidated statement of operations through investment and other income, net with a corresponding increase or decrease to the equity investment.

Business Combinations (Tables)

Business Combinations (Tables)	12 Months Ended
	Dec. 31, 2021
Business Combination and Asset Acquisition [Abstract]
Reconciliation of equity (net assets) attributable to noncontrolling interest	The following is a reconciliation of equity (net assets) attributable to the noncontrolling interest (in thousands): December 31, 2021 2020 Noncontrolling interest at beginning of period $ 24,795 $ 6,821 Net loss attributable to noncontrolling interest (7,368) (450) Contributions from noncontrolling interest holders of Zentera — 18,424 Deconsolidation of Zentera (16,899) — Noncontrolling interest at end of period $ 528 $ 24,795

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	12 Months Ended
	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Components of available-for-sale marketable securities	Available-for-sale marketable securities consisted of the following (in thousands): December 31, 2021 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Commercial paper $ 199,321 $ 11 $ (55) $ 199,277 Corporate debt securities 10,085 — (7) 10,078 US government agencies 20,032 1 — 20,033 US Treasury securities 50,860 — (75) 50,785 $ 280,298 $ 12 $ (137) $ 280,173
Contractual maturities of available-for-sale debt securities	Contractual maturities of available-for-sale debt securities are as follows (in thousands): December 31, 2021 Estimated Fair Value Due within one year $ 258,948 After one but within five years 21,225 $ 280,173
Schedule of fair value, assets and liabilities measured on recurring basis	The following table summarizes, by major security type, our cash equivalents and available-for-sale marketable securities that are measured at fair value on a recurring basis and are categorized using the fair value hierarchy (in thousands): December 31, 2021 December 31, 2020 Level 1 Level 2 Total estimated fair value Level 1 Level 2 Total estimated fair value Cash equivalents: Money market funds $ 43,653 $ — $ 43,653 $ 24,016 $ — $ 24,016 Corporate debt securities — — — — 4,999 4,999 Total cash equivalents: 43,653 — 43,653 24,016 4,999 29,015 Available-for-sale marketable securities: Commercial paper — 199,277 199,277 — 147,388 147,388 Corporate debt securities — 10,078 10,078 — 23,571 23,571 US government agencies — 20,033 20,033 — 81,486 81,486 US Treasury securities 50,785 — 50,785 31,109 — 31,109 Total available-for-sale marketable securities: 50,785 229,388 280,173 31,109 252,445 283,554 Total assets measured at fair value $ 94,438 $ 229,388 $ 323,826 $ 55,125 $ 257,444 $ 312,569

Prepaid Expenses and Other As_2

Prepaid Expenses and Other Assets (Tables)	12 Months Ended
	Dec. 31, 2021
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Summary of prepaid expenses and other assets	Prepaid expenses and other assets consisted of the following (in thousands): December 31, 2021 2020 Prepaid insurance $ 990 $ 1,021 Prepaid software licenses and maintenance 403 563 Foreign R&D credit refund 1,808 692 Prepaid research and development expenses 11,204 5,963 Interest receivable 258 478 Zentera receivable 2,373 — Other prepaid expenses 640 441 Total prepaid expenses and other current assets 17,676 9,158 Less long-term portion 7,040 2,976 Total prepaid expenses and other assets, current $ 10,636 $ 6,182

Property and Equipment, net (Ta

Property and Equipment, net (Tables)	12 Months Ended
	Dec. 31, 2021
Property, Plant and Equipment [Abstract]
Summary of property and equipment, net	Property and equipment, net consisted of the following (in thousands): December 31, 2021 2020 Lab equipment $ 2,057 $ 424 Leasehold improvements 4,515 49 Office equipment and furniture 2,123 405 Computer equipment 211 124 Construction in process 34 347 Subtotal 8,940 1,349 Accumulated depreciation and amortization (792) (250) Property and equipment, net $ 8,148 $ 1,099

Accrued Expenses (Tables)

Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2021
Payables and Accruals [Abstract]
Schedule of accrued expenses	Accrued expenses consist of the following (in thousands): December 31, 2021 2020 Accrued research and development expenses $ 18,531 $ 11,947 Accrued employee expenses 9,250 5,649 Accrued general and administrative expenses 1,480 996 Lease liability 1,453 902 Income taxes payable 971 410 Other 669 36 Total accrued expenses $ 32,354 $ 19,940

Equity and Share-based Compen_2

Equity and Share-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2021
Equity [Abstract]
Schedule of share-based compensation expense	Total share-based compensation expense related to share based awards was comprised of the following (in thousands): Year ended December 31, 2021 2020 2019 Research and development expense $ 20,858 $ 7,296 $ 339 General and administrative expense 14,879 15,850 278 Total share-based compensation expense $ 35,737 $ 23,146 $ 617 Share-based compensation expense by type of share-based award (in thousands): Year ended December 31, 2021 2020 2019 Profits interest award units $ — $ 329 $ 617 Stock options 20,773 6,925 — RSAs and RSUs 14,643 15,892 — Employee Stock Purchase Plan 321 — — $ 35,737 $ 23,146 $ 617
Share-based compensation expense by type of share-based award	Total unrecognized estimated compensation cost by type of award and the weighted average requisite service period over which such expense is expected to be recognized (in thousands, unless otherwise noted): December 31, 2021 Unrecognized Remaining Stock options $ 71,753 3.0 RSAs 1,244 1.6 RSUs 6,157 2.3
Summary of profits interest units award activity	The following table provides a summary of the profits interest units award activity under the Plan. The amounts include profits interest units granted to both employees and non-employees: Number of Units Weighted Average Outstanding at Outstanding at December 31, 2018 1,612,311 $ 1.56 Granted 1,095,545 $ 2.73 Forfeited (37,188) $ 1.62 Outstanding at Outstanding at December 31, 2019 2,670,668 $ 2.04 Granted 70,000 $ 3.06 Cancelled upon conversion (2,740,668) $ 2.07 Outstanding at December 31, 2020 — $ —
Schedule of valuation assumptions	The fair value of the profits interest award units was estimated using an option pricing model with the following assumptions: Year ended December 31, 2020 2019 Members’ equity value (in thousands) $271,207 $197,041 - $271,207 Threshold amounts (in thousands) $309,824 $143,800 - $309,824 Risk-free rate 1.5% 1.5% Volatility 75.0% 75.0% Time to liquidity (in years) 1.1 1.1 - 1.8 Lack of marketability discount 26.5% 18.8% - 26.4% Grant date fair value $3.06 $1.88 - $3.06 Year ended December 31, 2021 2020 Expected volatility 73.2% - 76.6% 76.4% - 78.7% Average expected term (in years) 5.2 - 6.1 1.0 - 6.0 Risk-free interest rate 0.5% - 1.3% 0.1% - 0.5% Expected dividend yield —% —%
Summary of stock option activity	The following table summarizes option activity for the year ended December 31, 2021. The amounts include incentive units granted to both employees and non-employees: Number of Shares Weighted Average Weighted Average Remaining Contractual Term (Years) Aggregate Intrinsic Value (in thousands) Outstanding at December 31, 2020 3,121,221 $ 25.45 Granted 1,527,300 $ 50.95 Exercised (232,684) $ 30.73 Cancelled (172,355) $ 34.49 Outstanding at December 31, 2021 4,243,482 $ 33.97 8.7 $212,566 Vested and expected to vest at December 31, 2021 4,243,482 $ 33.97 8.7 $212,566 Exercisable at December 31, 2021 1,141,421 $ 24.84 8.4 $67,600
Summary of RSA activity	The following table provides a summary of the RSA activity. The amounts include incentive units granted to both employees and non-employees: Number of Shares Weighted Average Grant Date Outstanding at Outstanding at December 31, 2020 742,411 $ 3.03 Vested (376,117) $ 4.39 Forfeited (4,462) $ 3.80 Outstanding at December 31, 2021 361,832 $ 3.47
Summary of RSU activity	The following table provides a summary of the restricted stock unit ("RSU") activity under the 2020 Plan. The amounts include incentive units granted to both employees and non-employees: Number of Shares Weighted Average Grant Date Outstanding at December 31, 2020 674,757 $ 23.75 Granted 158,750 $ 39.82 Vested (533,911) $ 23.75 Forfeited (25,401) $ 23.75 Outstanding at December 31, 2021 274,195 $ 33.06
Schedule of valuation assumptions, ESPP	The weighted average assumptions used to estimate the fair value of stock purchase rights under the employee stock purchase plan are as follows: Year ended December 31, 2021 2020 ESPP Volatility 48.2 % — Expected term (years) 0.5 — Risk free rate 0.1 % — Expected dividend yield — % —

Commitment and Contingencies (T

Commitment and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Summary of operating lease terms	The following table presents the weighted average remaining lease term and weighted average discount rates related to our operating leases as of December 31, 2021: Weighted average remaining lease term (in years) 10.7 Weighted average discount rate 9.0%
Schedule of future minimum operating lease payments	Approximate annual future minimum operating lease payments as of December 31, 2021 are as follows (in thousands): Year Amount 2022 $ 3,277 2023 6,352 2024 6,498 2025 6,973 2026 7,291 Thereafter 45,622 Total minimum lease payments: 76,013 Less: imputed interest 30,101 Total operating lease liabilities 45,912 Less: current portion 1,453 Lease liability, net of current portion $ 44,459

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Schedule of net losses before income taxes and loss on equity method investment by domestic and foreign operations	The amount of net loss before income taxes and loss on equity method investment for the years ended December 31, 2021, 2020 and 2019 is as follows (in thousands): Year ended December 31, 2021 2020 2019 U.S. net loss before income taxes $ (171,053) $ (112,827) $ (46,363) Foreign net income (loss) before income taxes 4,663 (5,277) — Net loss before income taxes and loss on equity method investment $ (166,390) $ (118,104) $ (46,363)
Schedule of components of income tax provision (benefit) for federal and state income taxes	The following table presents the current and deferred income tax provision (benefit) for federal, state and foreign income taxes (in thousands): Year ended December 31, 2021 2020 2019 Current tax provision: Federal $ — $ — $ — State 11 16 $ 15 Foreign 550 410 $ — Total current tax provision 561 426 $ 15 Deferred tax provision: Federal (120) — — State (736) — — Foreign (2) 18 — Total deferred tax provision (858) 18 — Total provision for income taxes: $ (297) $ 444 $ 15
Schedule of effective income tax rate reconciliation	The following table is a reconciliation of the expected tax computed at the U.S. statutory federal income tax rate to the total provision for income taxes (in thousands): Year ended December 31, 2021 2020 2019 Expected tax at 21% $ (34,941) 21.0 % $ (24,802) 21.0 % $ (9,730) 21.0 % State income tax, net of federal tax (931) 0.6 % 273 (0.3) % (3,167) 6.8 % Limited liability company loss — — % — — % 4 — % Non-deductible expenses — — % — — % 164 (0.3) % Research credits (6,938) 4.2 % (4,025) 3.4 % (1,424) 3.1 % Share-based compensation (3,307) 2.0 % (1,718) 1.5 % — — % Other 939 (0.6) % 146 (0.1) % (2) — % Section 162(m) limitations 3,982 (2.4) % 2,956 (2.5) % — — % Change in valuation allowance 40,899 (24.6) % 27,614 (23.4) % 14,170 (30.6) % Provision for income taxes $ (297) 0.2 % $ 444 (0.4) % $ 15 0.0 %
Schedule of deferred tax assets and liabilities	Significant components of our net deferred tax asset or liability are as follows (in thousands): December 31, 2021 2020 Deferred tax assets Net operating loss $ 82,117 $ 45,730 Compensation 1,553 892 Share-based compensation 4,123 1,691 ASC 842 lease liability 9,740 425 Intangibles 2,004 — Accrued liabilities 675 632 Research credits 14,466 7,528 Total gross deferred tax assets 114,678 56,898 Valuation allowance (97,160) (56,261) Net deferred tax assets 17,518 637 Deferred tax liabilities Depreciable assets (1,699) (145) ASC 842 right of use asset (9,481) (502) In-process research and development — (2,463) Equity method investment (7,954) — Other (6) (7) Deferred tax liabilities (19,140) (3,117) Net deferred tax liabilities $ (1,622) $ (2,480)
Schedule of unrecognized tax benefits roll forward	The following table summarized the activity related to our unrecognized tax benefits (in thousands): December 31, 2021 2020 2019 Gross unrecognized tax benefits at the beginning of the year $ 1,932 $ 1,124 $ 741 Increase related to current year tax positions 969 661 383 Increase related to prior year tax positions — 197 — Decrease related to prior year tax positions (66) (50) — Gross unrecognized tax benefits at end of the year $ 2,835 $ 1,932 $ 1,124

Net Loss Per Common Share_Cla_2

Net Loss Per Common Share/Class A Common Unit (Tables)	12 Months Ended
	Dec. 31, 2021
Earnings Per Share [Abstract]
Schedule of basic and diluted net loss per unit	Basic and diluted net loss per common share/Class A common unit were calculated as follows (in thousands except per share amounts): Year ended December 31, 2021 2020 2019 Numerator: Net loss attributable to Zentalis $ (158,725) $ (117,841) $ (45,663) Denominator: Weighted average number of common shares/Class A common units outstanding, basic and diluted 42,688 28,113 5,597 Net loss per common share $ (3.72) $ (4.19) $ — Net loss per Class A common unit $ (8.16)
Schedule of antidilutive securities excluded from computation of earnings per unit	The following common stock/Class A common unit equivalents have been excluded from the calculations of diluted net loss per common share/Class A common unit because their inclusion would be antidilutive (in thousands). Year ended December 31, 2021 2020 2019 Preferred units, as if converted to Class A common units — — 9,950 Incentive units - Class B common units — — 2,671 Outstanding stock options 4,243 3,121 — Unvested RSAs 361 742 — Unvested RSUs 274 675 — 4,878 4,538 12,621

Selected Quarterly Financial _2

Selected Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2021
Quarterly Financial Information Disclosure [Abstract]
Schedule of quarterly results	Selected quarterly financial data is as follows: Three months ended 3/31/2021 6/30/2021 9/30/2021 12/31/2021 Operating Expenses Research and development $ 38,394 $ 44,770 $ 53,998 $ 38,439 General and administrative $ 11,953 $ 10,362 $ 8,872 $ 9,754 Total operating expenses 50,347 55,132 62,870 48,193 Operating loss (50,347) (55,132) (62,870) (48,193) Other Income (Expense) Investment and other income (expense), net $ 99 $ 115 $ 99 $ 88 Gain on deconsolidation of Zentera $ — $ — $ 51,582 $ — Net loss before income taxes (50,248) (55,017) (11,189) (48,105) Income tax expense $ 196 $ 45 $ (697) $ 159 Loss on equity method investment $ — $ — $ — $ 1,831 Net loss (50,444) (55,062) (10,492) (50,095) Net loss attributable to noncontrolling interests (543) (488) (6,301) (36) Net loss attributable to Zentalis $ (49,901) $ (54,574) $ (4,191) $ (50,059) Net loss per common share outstanding, basic and diluted $ (1.24) $ (1.34) $ (0.09) $ (1.11) Common shares used in computing net loss per share, basic and diluted 40,359 40,738 44,609 44,976 Three months ended 3/31/2020 6/30/2020 9/30/2020 12/31/2020 Operating Expenses Research and development $ 13,258 $ 17,452 $ 24,670 $ 29,521 General and administrative $ 3,141 $ 9,924 $ 10,097 $ 10,724 Total operating expenses 16,399 27,376 34,767 40,245 Operating loss (16,399) (27,376) (34,767) (40,245) Other Income (Expense) Investment and other income (expense), net $ 164 $ 84 $ 120 $ 315 Net loss before income taxes (16,235) (27,292) (34,647) (39,930) Income tax expense $ — $ — $ 18 $ 426 Net loss (16,235) (27,292) (34,665) (40,356) Net loss attributable to noncontrolling interests (109) (435) (110) (53) Net loss attributable to Zentalis $ (16,126) $ (26,857) $ (34,555) $ (40,303) Net loss per common share outstanding, basic and diluted $ (0.78) $ (0.91) $ (1.01) Net loss per Class A common unit outstanding, basic and diluted $ (2.88) Common shares/units used in computing net loss per share/Class A common unit, basic and diluted 5,601 34,353 37,959 39,936

Organization and Business (Deta

Organization and Business (Details) $ / shares in Units, $ in Thousands	Jul. 01, 2021shares	Aug. 03, 2020shares	Apr. 07, 2020USD ($)$ / sharesshares	Apr. 02, 2020$ / sharesshares	Dec. 21, 2017	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Class of Stock [Line Items]
Exchange ratio					1
Proceeds from issuance of common stock in initial public offering, net | $			$ 190,000			$ 0	$ 172,482	$ 0
Issuance fees and expenses | $			17,600
IPO
Class of Stock [Line Items]
Share price (in dollars per sharee) | $ / shares				$ 18
Proceeds from issuance of common stock in initial public offering, net | $			190,000
Issuance fees and expenses | $			$ 17,600
Common Stock | IPO
Class of Stock [Line Items]
Share price (in dollars per sharee) | $ / shares			$ 18
Number of shares converted | shares				25,288,854
Number of shares issued and sold | shares			10,557,000
Common Stock | Underwriters
Class of Stock [Line Items]
Share price (in dollars per sharee) | $ / shares			$ 18
Number of shares issued and sold | shares	465,000	618,750	1,377,000
Unvested RSAs | IPO
Class of Stock [Line Items]
Number of shares converted | shares				1,160,277

Summary of Significant Accoun_4

Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Variable Interest Entity [Line Items]
Restricted cash	$ 2.9	$ 1.3
Operating lease, liability, current, balance sheet location	Accrued expenses	Accrued expenses
Minimum | Equipment
Variable Interest Entity [Line Items]
Property, plant and equipment, useful life (years)	3 years
Maximum | Equipment
Variable Interest Entity [Line Items]
Property, plant and equipment, useful life (years)	5 years

Significant Transactions (Detai

Significant Transactions (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended	12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Schedule of Equity Method Investments [Line Items]
Investment in Zentera	$ 37,495				$ 37,495	$ 37,495	$ 0
Deferred tax liability upon deconsolidation of Zentera	7,954				7,954	7,954	0
Gain on deconsolidation of Zentera	0	$ 51,582	$ 0	$ 0		51,582	$ 0	$ 0
Zentera Sublicenses
Schedule of Equity Method Investments [Line Items]
Deferred tax liability upon deconsolidation of Zentera	8,000				8,000	8,000
Gain on deconsolidation of Zentera						51,600
In-process research and development	$ 7,100				7,100	$ 7,100
Contra-research and development expense					$ 5,300

Business Combinations - Narrati

Business Combinations - Narrative (Details) - USD ($)	Dec. 21, 2017	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Variable Interest Entity [Line Items]
IPR&D impairment		$ 8,800,000	$ 0	$ 0
Reversal of deferred tax liability due to IPR&D impairment		2,500,000
In Process Research and Development
Variable Interest Entity [Line Items]
IPR&D impairment		8,800,000
In-process research and development		$ 0	$ 8,800,000
Kalyra Pharmaceuticals, Inc.
Variable Interest Entity [Line Items]
Cash payments to acquire interest	$ 4,500,000
Ownership percentage	25.00%

Business Combinations - Reconci

Business Combinations - Reconciliation of Equity (Net Assets) Attributable to Noncontrolling Interest (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Net loss attributable to noncontrolling interest	$ (36)	$ (6,301)	$ (488)	$ (543)	$ (53)	$ (110)	$ (435)	$ (109)	$ (7,368)	$ (707)	$ (715)
Contributions from noncontrolling interest holders of Zentera										18,424
Deconsolidation of Zentera									(16,899)
VIE, Primary Beneficiary
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Noncontrolling interest at beginning of period				$ 24,795				$ 6,821	24,795	6,821
Net loss attributable to noncontrolling interest									(7,368)	(450)
Contributions from noncontrolling interest holders of Zentera									0	18,424
Deconsolidation of Zentera									(16,899)	0
Noncontrolling interest at end of period	$ 528				$ 24,795				$ 528	$ 24,795	$ 6,821

Fair Value Measurement - Compon

Fair Value Measurement - Components of Available-for-sale Marketable Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 280,298
Gross Unrealized Gains	12
Gross Unrealized Losses	(137)
Estimated Fair Value	280,173	$ 283,554
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	199,321
Gross Unrealized Gains	11
Gross Unrealized Losses	(55)
Estimated Fair Value	199,277	147,388
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	10,085
Gross Unrealized Gains	0
Gross Unrealized Losses	(7)
Estimated Fair Value	10,078	23,571
US government agencies
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	20,032
Gross Unrealized Gains	1
Gross Unrealized Losses	0
Estimated Fair Value	20,033	81,486
US Treasury securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	50,860
Gross Unrealized Gains	0
Gross Unrealized Losses	(75)
Estimated Fair Value	$ 50,785	$ 31,109

Fair Value Measurement - Narrat

Fair Value Measurement - Narrative (Details) $ in Thousands	Dec. 31, 2021USD ($)security
Fair Value Disclosures [Abstract]
Number of available-for-sale securities in unrealized loss position | security	29
Debt securities fair market value	$ 174,600
Fair value of available-for-sale securities in unrealized loss position	$ 137,000

Fair Value Measurement - Contra

Fair Value Measurement - Contractual Maturities of Available-for-sale Securities (Details) $ in Thousands	Dec. 31, 2021USD ($)
Fair Value Disclosures [Abstract]
Due within one year	$ 258,948
After one but within five years	21,225
Estimated Fair Value	$ 280,173

Fair Value Measurement - Fair V

Fair Value Measurement - Fair Value of Assets Measured on a Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash equivalents	$ 43,653	$ 29,015
Marketable securities, available for sale	280,173	283,554
Total assets measured at fair value	323,826	312,569
Level 1
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash equivalents	43,653	24,016
Marketable securities, available for sale	50,785	31,109
Total assets measured at fair value	94,438	55,125
Level 2
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash equivalents	0	4,999
Marketable securities, available for sale	229,388	252,445
Total assets measured at fair value	229,388	257,444
Commercial paper
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Marketable securities, available for sale	199,277	147,388
Commercial paper | Level 1
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Marketable securities, available for sale	0	0
Commercial paper | Level 2
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Marketable securities, available for sale	199,277	147,388
Corporate debt securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Marketable securities, available for sale	10,078	23,571
Corporate debt securities | Level 1
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Marketable securities, available for sale	0	0
Corporate debt securities | Level 2
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Marketable securities, available for sale	10,078	23,571
US government agencies
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Marketable securities, available for sale	20,033	81,486
US government agencies | Level 1
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Marketable securities, available for sale	0	0
US government agencies | Level 2
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Marketable securities, available for sale	20,033	81,486
US Treasury securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Marketable securities, available for sale	50,785	31,109
US Treasury securities | Level 1
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Marketable securities, available for sale	50,785	31,109
US Treasury securities | Level 2
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Marketable securities, available for sale	0	0
Money market funds
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash equivalents	43,653	24,016
Money market funds | Level 1
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash equivalents	43,653	24,016
Money market funds | Level 2
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash equivalents	0	0
Corporate debt securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash equivalents	0	4,999
Corporate debt securities | Level 1
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash equivalents	0	0
Corporate debt securities | Level 2
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash equivalents	$ 0	$ 4,999

Prepaid Expenses and Other As_3

Prepaid Expenses and Other Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid insurance	$ 990	$ 1,021
Prepaid software licenses and maintenance	403	563
Foreign R&D credit refund	1,808	692
Prepaid research and development expenses	11,204	5,963
Interest receivable	258	478
Zentera receivable	2,373	0
Other prepaid expenses	640	441
Total prepaid expenses and other current assets	17,676	9,158
Less long-term portion	7,040	2,976
Total prepaid expenses and other assets, current	$ 10,636	$ 6,182

Property and Equipment, net - S

Property and Equipment, net - Summary (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Subtotal	$ 8,940	$ 1,349
Accumulated depreciation and amortization	(792)	(250)
Property and equipment, net	8,148	1,099
Lab equipment
Property, Plant and Equipment [Line Items]
Subtotal	2,057	424
Leasehold improvements
Property, Plant and Equipment [Line Items]
Subtotal	4,515	49
Office equipment and furniture
Property, Plant and Equipment [Line Items]
Subtotal	2,123	405
Computer equipment
Property, Plant and Equipment [Line Items]
Subtotal	211	124
Construction in process
Property, Plant and Equipment [Line Items]
Subtotal	$ 34	$ 347

Property and Equipment, net - N

Property and Equipment, net - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Depreciation and amortization	$ 544	$ 160	$ 111

Accrued Expenses (Details)

Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Payables and Accruals [Abstract]
Accrued research and development expenses	$ 18,531	$ 11,947
Accrued employee expenses	9,250	5,649
Accrued general and administrative expenses	1,480	996
Lease liability	1,453	902
Income taxes payable	971	410
Other	669	36
Total accrued expenses	$ 32,354	$ 19,940

Convertible Preferred Units (De

Convertible Preferred Units (Details) - USD ($) $ / shares in Units, $ in Thousands	Apr. 07, 2020	Feb. 29, 2020	Sep. 30, 2019	Dec. 31, 2017	Sep. 30, 2015	Mar. 31, 2016	Aug. 31, 2018	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Class of Stock [Line Items]
Net proceeds from issuance of convertible preferred units								$ 0	$ 14,228	$ 81,876
Issuance costs of financing	$ 17,600
Shares issued (in shares)								0	0
Units authorized (in shares)								0	0
Shares outstanding (in shares)								0	0
Dividends declared (in dollars per share)								$ 0
Automatic conversion feature, minimum gross cash proceeds received in a public offering								$ 75,000
Series A Preferred Units
Class of Stock [Line Items]
Convertible preferred units issued (in shares)					1,293,104
Par value per share (in dollars per share)					$ 11.60	$ 11.60
Gross proceeds from issuance of convertible preferred units					$ 15,000	$ 3,300
Net proceeds from issuance of convertible preferred units					14,900
Issuance costs of financing					$ 100	$ 39
Shares issued (in shares)						286,205
Conversion price (in dollars per share)								$ 11.60
Liquidation preference (in dollars per share)								11.60
Series B Preferred Units
Class of Stock [Line Items]
Par value per share (in dollars per share)				$ 12.43			$ 12.43
Gross proceeds from issuance of convertible preferred units				$ 34,000			$ 9,800
Net proceeds from issuance of convertible preferred units				32,100			9,500
Issuance costs of financing				$ 1,900			$ 300
Shares issued (in shares)				2,735,320			788,419
Conversion price (in dollars per share)								12.43
Liquidation preference (in dollars per share)								12.43
Series C Preferred Units
Class of Stock [Line Items]
Par value per share (in dollars per share)		$ 17.50	$ 17.50						$ 17.50	$ 17.50
Gross proceeds from issuance of convertible preferred units		$ 15,200	$ 84,800
Net proceeds from issuance of convertible preferred units		14,200	81,900
Issuance costs of financing		$ 1,000	$ 2,900
Shares issued (in shares)		867,194	4,847,106
Conversion price (in dollars per share)								17.50
Liquidation preference (in dollars per share)								$ 17.50

Equity and Share-based Compen_3

Equity and Share-based Compensation - Narrative (Details)	Jul. 01, 2021USD ($)$ / sharesshares	Aug. 03, 2020USD ($)$ / sharesshares	Apr. 07, 2020USD ($)$ / sharesshares	Apr. 02, 2020$ / sharesshares	May 31, 2021USD ($)	Apr. 30, 2020shares	Dec. 31, 2017USD ($)shares	Sep. 30, 2015USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2021USD ($)$ / sharesshares	Aug. 31, 2018USD ($)	Dec. 31, 2021USD ($)$ / sharesshares	Dec. 31, 2020USD ($)$ / sharesshares	Dec. 31, 2019USD ($)shares	Mar. 15, 2021shares	Sep. 30, 2019shares	Dec. 21, 2017shares
Class of Stock [Line Items]
Common stock issued (in shares)							5,187,554			45,490,764		45,490,764	41,040,286
Common stock outstanding (in shares)							5,187,554			45,490,764		45,490,764	41,040,286
Common stock subject to future vesting provisions (in shares)							406,831
Common stock, shares authorized				250,000,000						250,000,000		250,000,000	250,000,000
Common stock, par value (in dollars per share) | $ / shares				$ 0.001						$ 0.001		$ 0.001	$ 0.001
Preferred stock, shares authorized				10,000,000						10,000,000		10,000,000	10,000,000
Preferred stock, par value (in dollars per share) | $ / shares				$ 0.001						$ 0.001		$ 0.001	$ 0.001
Proceeds from issuance of common stock in initial public offering, net | $			$ 190,000,000									$ 0	$ 172,482,000	$ 0
Issuance fees and expenses | $			17,600,000
Proceeds from issuance of common stock, net | $												$ 171,973,000	$ 155,305,000	0
Issuance of common stock upon exercise of options (in shares)												232,684
Proceeds from exercises of stock options | $												$ 7,200,000
Options, weighted average grant date fair value (dollars per share) | $ / shares												$ 33.27	$ 16.79
Intrinsic value of options exercised | $												$ 8,800,000	$ 0
Common Stock
Class of Stock [Line Items]
Stock issued (in shares)												3,691,000	4,744,000
Stock issued upon conversion of units (in shares)													10,278,000
Issuance of common stock upon exercise of options (in shares)												232,000
Issuance of common stock in connection with restricted stock unit vesting (in shares)												516,831	426,000
IPO
Class of Stock [Line Items]
Share price (in dollars per sharee) | $ / shares				$ 18
Proceeds from issuance of common stock in initial public offering, net | $			190,000,000
Issuance fees and expenses | $			$ 17,600,000
IPO | Common Stock
Class of Stock [Line Items]
Stock issued (in shares)													10,589,000
Follow-On Offering
Class of Stock [Line Items]
Gross proceeds from issuance of common stock | $		$ 166,000,000
Expenses and fees from the issuance of common stock | $	$ 10,700,000	$ 10,800,000
Proceeds from issuance of common stock, net | $	$ 172,900,000
Sales Agreement
Class of Stock [Line Items]
Gross proceeds from issuance of common stock | $										$ 10,000,000
Expenses and fees from the issuance of common stock | $										$ 300,000
Maximum gross sales proceeds | $					$ 200,000,000
The 2020 Plan
Class of Stock [Line Items]
Outstanding awards (in shares)										4,517,677		4,517,677
Shares available for future grants (in shares)										1,971,266		1,971,266
Zentera Stock Plan
Class of Stock [Line Items]
Share-based compensation prior to deconsolidation | $												$ 138,000	$ 187,000	$ 0
2020 ESPP
Class of Stock [Line Items]
Employee Stock Purchase Plan (ESPP), number of shares available						450,000
Employee Stock Purchase Plan (ESPP), number of shares outstanding, percentage						0.01
Employee Stock Purchase Plan (ESPP), number of shares available, other term in calculation						1,500,000
Amended 2020 ESPP
Class of Stock [Line Items]
Employee Stock Purchase Plan (ESPP), shares in ESPP reserve															2,000,000
Series A Preferred Units
Class of Stock [Line Items]
Preferred units authorized (in shares)							1,638,000
Issuance fees and expenses | $								$ 100,000	$ 39,000
Series B Preferred Units
Class of Stock [Line Items]
Preferred units authorized (in shares)							3,621,000
Issuance fees and expenses | $							$ 1,900,000				$ 300,000
Class A Common Units
Class of Stock [Line Items]
Common units, authorized (in shares)							15,000,000
Stock issued (in shares)												0	0
Common units subject to future vesting conditions (in shares)										0		0	0
Class A Common Units | Common Stock
Class of Stock [Line Items]
Stock issued upon conversion of units (in shares)													5,601,000
Class B Common Units
Class of Stock [Line Items]
Common units, authorized (in shares)							872,620									3,458,522
Stock issued upon conversion of units (in shares)							703,000
Class B Common Units | Common Stock
Class of Stock [Line Items]
Stock issued (in shares)														1,059,000
Stock issued upon conversion of units (in shares)													2,607,000
Class B Common Units | The Plan
Class of Stock [Line Items]
Shares authorized to be issued under plan (in shares)																	3,458,522
Class B Common Units | The 2020 Plan | Maximum
Class of Stock [Line Items]
Shares authorized to be issued under plan (in shares)						1,250,000
Common Stock | Corporate Conversion
Class of Stock [Line Items]
Stock issued (in shares)				0
Common Stock | IPO
Class of Stock [Line Items]
Stock issued upon conversion of units (in shares)				25,288,854
Stock issued (in dollars per share) | $ / shares				$ 18
Number of shares issued and sold			10,557,000
Share price (in dollars per sharee) | $ / shares			$ 18
Common Stock | Underwriters
Class of Stock [Line Items]
Number of shares issued and sold	465,000	618,750	1,377,000
Share price (in dollars per sharee) | $ / shares			$ 18
Common Stock | Follow-On Offering
Class of Stock [Line Items]
Number of shares issued and sold	3,565,000	4,743,750
Share price (in dollars per sharee) | $ / shares	$ 48.50	$ 35
Common Stock | Sales Agreement
Class of Stock [Line Items]
Number of shares issued and sold										125,643
Common Stock | Weighted Average | Sales Agreement
Class of Stock [Line Items]
Share price (in dollars per sharee) | $ / shares										$ 79.59		$ 79.59
Common Stock | The 2020 Plan
Class of Stock [Line Items]
Shares authorized to be issued under plan (in shares)						5,600,000
Percent of common stock outstanding used as threshold to calculate shares available for issuance						5.00%
Unvested RSAs | IPO
Class of Stock [Line Items]
Stock issued upon conversion of units (in shares)				1,160,277
Outstanding stock options
Class of Stock [Line Items]
Generally expected vesting term of the option contract (in years)												10 years
Expected dividend yield												0.00%	0.00%
Unvested RSUs
Class of Stock [Line Items]
Shares surrendered for minimum withholding taxes (in shares)												17,080
Minimum withholding taxes | $												$ 1,100,000
Grant date fair value of shares vested | $												12,700,000	$ 10,100,000
Fair value of vested shares | $												26,400,000	21,800,000
Unvested RSAs
Class of Stock [Line Items]
Grant date fair value of shares vested | $												1,700,000	1,100,000
Fair value of vested shares | $												$ 21,000,000	$ 14,300,000
Employee Stock Purchase Plan
Class of Stock [Line Items]
Expected dividend yield												0.00%	0.00%
Employee Stock Purchase Plan (ESPP) maximum percent of compensation to contribute										20.00%		20.00%
Employee Stock Purchase Plan (ESPP) maximum contribution amount | $												$ 21,250
Employee Stock Purchase Plan (ESPP), purchase price of common stock, percent of market price												85.00%
Employee Stock Purchase Plan (ESPP), offering period												6 months

Equity and Share-based Compen_4

Equity and Share-based Compensation - Share-based Compensation Related to Share Based Awards (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	$ 35,737	$ 23,146	$ 617
Research and development expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	20,858	7,296	339
General and administrative expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	$ 14,879	$ 15,850	$ 278

Equity and Share-based Compen_5

Equity and Share-based Compensation - Share-based Compensation Expense by Type of Share-based Awards (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	$ 35,737	$ 23,146	$ 617
Profits interest award units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	0	329	617
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	20,773	6,925	0
RSAs and RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	14,643	15,892	0
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation expense	$ 321	$ 0	$ 0

Equity and Share-based Compen_6

Equity and Share-based Compensation - Unrecognized Compensation Cost (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)
Outstanding stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options	$ 71,753
Remaining Weighted-Average Recognition Period (Years)	3 years
Unvested RSAs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized expense, other than options	$ 1,244
Remaining Weighted-Average Recognition Period (Years)	1 year 7 months 6 days
Unvested RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized expense, other than options	$ 6,157
Remaining Weighted-Average Recognition Period (Years)	2 years 3 months 18 days

Equity and Share-based Compen_7

Equity and Share-based Compensation - Equity instruments Other than Options (Details) - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Profit Interest Awards
Activity
Outstanding at the beginning of the period (in shares)	0	2,670,668	1,612,311
Granted (in shares)		70,000	1,095,545
Forfeited (in shares)		(2,740,668)	(37,188)
Outstanding at the end of the period (in shares)		0	2,670,668
Weighted Average Grant Date Fair Value
Outstanding, weighted average grant date fair value beginning of the period (in dollars per share)	$ 0	$ 2.04	$ 1.56
Granted, (in dollars per share)		3.06	2.73
Forfeited (in dollars per share)		2.07	1.62
Outstanding, weighted average grant date fair value end of the period (in dollars per share)		$ 0	$ 2.04
Restricted Stock Awards (RSAs)
Activity
Outstanding at the beginning of the period (in shares)	742,411
Vested (shares)	(376,117)
Forfeited (in shares)	(4,462)
Outstanding at the end of the period (in shares)	361,832	742,411
Weighted Average Grant Date Fair Value
Outstanding, weighted average grant date fair value beginning of the period (in dollars per share)	$ 3.03
Vested (in dollars per share)	4.39
Forfeited (in dollars per share)	3.80
Outstanding, weighted average grant date fair value end of the period (in dollars per share)	$ 3.47	$ 3.03
Restricted Stock Units (RSUs)
Activity
Outstanding at the beginning of the period (in shares)	674,757
Granted (in shares)	158,750
Vested (shares)	(533,911)
Forfeited (in shares)	(25,401)
Outstanding at the end of the period (in shares)	274,195	674,757
Weighted Average Grant Date Fair Value
Outstanding, weighted average grant date fair value beginning of the period (in dollars per share)	$ 23.75
Granted, (in dollars per share)	39.82
Vested (in dollars per share)	23.75
Forfeited (in dollars per share)	23.75
Outstanding, weighted average grant date fair value end of the period (in dollars per share)	$ 33.06	$ 23.75

Equity and Share-based Compen_8

Equity and Share-based Compensation - Fair Value Assumptions for Profit Interest Awards (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2021
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Members’ equity value (in thousands)	$ 308,582		$ 363,954
Profit Interest Awards
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Members’ equity value (in thousands)	271,207
Threshold amounts (in thousands)	$ 309,824
Risk free rate (as a percent)	1.50%	1.50%
Volatility (as a percent)	75.00%	75.00%
Time to liquidity (in years)	1 year 1 month 6 days
Lack of marketability discount (as a percent)	26.50%
Grant date fair value (in dollars per share)	$ 3.06	$ 2.73
Profit Interest Awards | Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Members’ equity value (in thousands)		$ 197,041
Threshold amounts (in thousands)		$ 143,800
Time to liquidity (in years)		1 year 1 month 6 days
Lack of marketability discount (as a percent)		18.80%
Grant date fair value (in dollars per share)		$ 1,880
Profit Interest Awards | Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Members’ equity value (in thousands)		$ 271,207
Threshold amounts (in thousands)		$ 309,824
Time to liquidity (in years)		1 year 9 months 18 days
Lack of marketability discount (as a percent)		26.40%
Grant date fair value (in dollars per share)		$ 3,060

Equity and Share-based Compen_9

Equity and Share-based Compensation - Summary of Option Activity (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)$ / sharesshares
Stock Option Activity
Outstanding at the beginning of the period (in shares) | shares	3,121,221
Options granted (in shares) | shares	1,527,300
Options exercised (in shares) | shares	(232,684)
Options cancelled (in shares) | shares	(172,355)
Outstanding at the ending of the period (in shares) | shares	4,243,482
Stock Options Weighted Average Exercise Price
Options outstanding, weighted average grant date fair value beginning of the period (in dollars per share) | $ / shares	$ 25.45
Options granted (in dollars per share) | $ / shares	50.95
Options exercised (in dollars per share) | $ / shares	30.73
Options cancelled (in dollars per share) | $ / shares	34.49
Options outstanding, weighted average grant date fair value ending of the period (in dollars per share) | $ / shares	$ 33.97
Stock Option Activity, Additional Disclosures
Options outstanding, weighted average remaining contractual term (years)	8 years 8 months 12 days
Options outstanding, aggregate intrinsic value (in USD) | $	$ 212,566
Options vested and expected to vest, number of options (in shares) | shares	4,243,482
Options vested and expected to vest, weighted average exercise price per share (in dollars per share) | $ / shares	$ 33.97
Options vested and expected to vest, weighted average remaining contractual term (years)	8 years 8 months 12 days
Options vested and expected to vest, aggregate intrinsic value (in USD) | $	$ 212,566
Options exercisable, number of options (in shares) | shares	1,141,421
Options exercisable, weighted average exercise price per share (in dollars per share) | $ / shares	$ 24.84
Options exercisable, weighted average remaining contractual term (years)	8 years 4 months 24 days
Options exercisable, aggregate intrinsic value (in USD) | $	$ 67,600

Equity and Share-based Compe_10

Equity and Share-based Compensation - Fair Value Assumptions for Stock Options (Details) - Outstanding stock options	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Expected dividend yield	0.00%	0.00%
Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Volatility (as a percent)	73.20%	76.40%
Average expected term (in years)	5 years 2 months 12 days	1 year
Risk free rate (as a percent)	0.50%	0.10%
Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Volatility (as a percent)	76.60%	78.70%
Average expected term (in years)	6 years 1 month 6 days	6 years
Risk free rate (as a percent)	1.30%	0.50%

Equity and Share-based Compe_11

Equity and Share-based Compensation - Fair Value Assumptions for Employee Stock Purchase Plan (Details) - Employee Stock Purchase Plan	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Volatility (as a percent)	48.20%	0.00%
Average expected term (in years)	6 months
Risk free rate (as a percent)	0.10%	0.00%
Expected dividend yield	0.00%	0.00%

Commitment and Contingencies -

Commitment and Contingencies - Narrative (Details) $ in Millions	1 Months Ended								12 Months Ended
	Sep. 30, 2021ft²option	Mar. 31, 2021ft²option	Nov. 30, 2020ft²	Sep. 30, 2020ft²	Aug. 31, 2019ft²	Apr. 30, 2019ft²	Dec. 31, 2018	Jan. 31, 2016ft²	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)
Lessee, Lease, Description [Line Items]
Operating lease, rent expense | $									$ 2.6	$ 1.1
Operating lease payments | $									$ 1.3	$ 1
San Diego | Building
Lessee, Lease, Description [Line Items]
Area of leased space (in square feet)				117,900				11,121
Potential annual increase to lease rent (percent)	0.030				0.030		0.030
Area of subleased space (in square feet)					2,333
Reduction due to amendment (in square feet)	43,200
Number of renewal options | option	2
Operating lease, renewal term (in years)	5 years
San Diego | Temporary Leased Building
Lessee, Lease, Description [Line Items]
Area of leased space (in square feet)			13,200
New York | Building
Lessee, Lease, Description [Line Items]
Area of leased space (in square feet)		31,362				4,800
Potential annual increase to lease rent (percent)		0.081				0.030
Anniversary year of potential rent increase post commencement date		6 years
Number of renewal options | option		1
Operating lease, renewal term (in years)		5 years

Commitment and Contingencies _2

Commitment and Contingencies - Summary of Operating Lease Terms (Details)	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Weighted average remaining lease term (in years)	10 years 8 months 12 days
Weighted average discount rate	9.00%

Commitment and Contingencies _3

Commitment and Contingencies - Future Minimum Lease Payments (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
2022	$ 3,277
2023	6,352
2024	6,498
2025	6,973
2026	7,291
Thereafter	45,622
Total minimum lease payments:	76,013
Less: imputed interest	30,101
Total operating lease liabilities	45,912
Lease liability	1,453	$ 902
Long-term lease liability	$ 44,459	$ 1,097

Income Taxes - Net Loss Before

Income Taxes - Net Loss Before Taxes And Loss on Equity Method Investment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
U.S. net loss before income taxes	$ (171,053)	$ (112,827)	$ (46,363)
Foreign net income (loss) before income taxes	4,663	(5,277)	0
Net loss before income taxes and loss on equity method investment	$ (166,390)	$ (118,104)	$ (46,363)

Income Taxes - Provision_Benefi

Income Taxes - Provision/Benefit (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Current tax provision:
Federal									$ 0	$ 0	$ 0
State									11	16	15
Foreign									550	410	0
Total current tax provision									561	426	15
Deferred tax provision:
Federal									(120)	0	0
State									(736)	0	0
Foreign									(2)	18	0
Total deferred tax provision									(858)	18	0
Total provision for income taxes:	$ 159	$ (697)	$ 45	$ 196	$ 426	$ 18	$ 0	$ 0	$ (297)	$ 444	$ 15

Income Taxes - Effective Income

Income Taxes - Effective Income Tax Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Effective Income Tax Rate Reconciliation, Amount
Expected tax at 21%									$ (34,941)	$ (24,802)	$ (9,730)
State income tax, net of federal tax									(931)	273	(3,167)
Limited liability company loss									0	0	4
Non-deductible expenses									0	0	164
Research credits									(6,938)	(4,025)	(1,424)
Share-based compensation									(3,307)	(1,718)	0
Other									939	146	(2)
Section 162(m) limitations									3,982	2,956	0
Change in valuation allowance									40,899	27,614	14,170
Total provision for income taxes:	$ 159	$ (697)	$ 45	$ 196	$ 426	$ 18	$ 0	$ 0	$ (297)	$ 444	$ 15
Effective Income Tax Rate Reconciliation, Percent
Expected tax at 21%									21.00%	21.00%	21.00%
State income tax, net of federal tax									0.60%	(0.30%)	6.80%
Limited liability company loss									0	0	0
Non-deductible expenses									0.00%	0.00%	(0.30%)
Research credits									4.20%	3.40%	3.10%
Share-based compensation									2.00%	1.50%	0.00%
Other									(0.60%)	(0.10%)	0.00%
Section 162(m) limitations									(0.024)	(0.025)	0
Change in valuation allowance									(24.60%)	(23.40%)	(30.60%)
Provision for income taxes									0.20%	(0.40%)	0.00%

Income Taxes Net Deferred Tax A

Income Taxes Net Deferred Tax Asset or Liability (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets
Net operating loss	$ 82,117	$ 45,730
Compensation	1,553	892
Share-based compensation	4,123	1,691
ASC 842 lease liability	9,740	425
Intangibles	2,004	0
Accrued liabilities	675	632
Research credits	14,466	7,528
Total gross deferred tax assets	114,678	56,898
Valuation allowance	(97,160)	(56,261)
Net deferred tax assets	17,518	637
Deferred tax liabilities
Depreciable assets	(1,699)	(145)
ASC 842 right of use asset	(9,481)	(502)
In-process research and development	0	(2,463)
Equity method investment	(7,954)	0
Other	(6)	(7)
Deferred tax liabilities	(19,140)	(3,117)
Net deferred tax liabilities	$ (1,622)	$ (2,480)

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($)	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating Loss Carryforwards [Line Items]
Deferred tax assets, valuation allowance	$ 97,160,000	$ 56,261,000
Unrecognized tax benefits that would not impact effective tax rate	2,600,000
Accrued interest and penalties associated with uncertain tax positions	0	0	$ 0
Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	361,100,000
Net operating loss carryforwards, not subject to expiration	340,200,000
Federal and state research tax credit carryforwards, net of reserves	10,500,000
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards		$ 90,400,000
Federal and state research tax credit carryforwards, net of reserves	$ 3,900,000

Income Taxes - Unrecognized Tax

Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Gross unrecognized tax benefits at the beginning of the year	$ 1,932	$ 1,124	$ 741
Increase related to current year tax positions	969	661	383
Increase related to prior year tax positions	0	197	0
Decrease related to prior year tax positions	(66)	(50)	0
Gross unrecognized tax benefits at end of the year	$ 2,835	$ 1,932	$ 1,124

Net Loss Per Common Share_Cla_3

Net Loss Per Common Share/Class A Common Unit - Calculation (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Numerator:
Net loss attributable to Zentalis	$ (50,059)	$ (4,191)	$ (54,574)	$ (49,901)	$ (40,303)	$ (34,555)	$ (26,857)	$ (16,126)	$ (158,725)	$ (117,841)	$ (45,663)
Denominator:
Common shares/units used in computing less loss per share/Class A common unit, basic (in shares)	44,976,000	44,609,000	40,738,000	40,359,000	39,936,000	37,959,000	34,353,000	5,601,000	42,688,000	28,113,000	5,597,000
Common shares/units used in computing less loss per share/Class A common unit, diluted (in shares)	44,976,000	44,609,000	40,738,000	40,359,000	39,936,000	37,959,000	34,353,000	5,601,000	42,688,000	28,113,000	5,597,000
Net loss per common share/Class A common unit outstanding, basic (in dollars per share)	$ (1.11)	$ (0.09)	$ (1.34)	$ (1.24)	$ (1.01)	$ (0.91)	$ (0.78)	$ (2.88)
Net loss per common share/Class A common unit outstanding, diluted (in dollars per share)	$ (1.11)	$ (0.09)	$ (1.34)	$ (1.24)	$ (1.01)	$ (0.91)	$ (0.78)	$ (2.88)	$ 0	$ 0	$ (8.16)
Common Stock
Denominator:
Net loss per common share/Class A common unit outstanding, basic (in dollars per share)									(3.72)	(4.19)	0
Net loss per common share/Class A common unit outstanding, diluted (in dollars per share)									(3.72)	(4.19)	0
Class A Common Units
Denominator:
Net loss per common share/Class A common unit outstanding, basic (in dollars per share)									$ 0	$ 0	(8.16)
Net loss per common share/Class A common unit outstanding, diluted (in dollars per share)											$ (8.16)

Net Loss Per Common Share_Cla_4

Net Loss Per Common Share/Class A Common Unit - Antidilutive Securities (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per unit (in shares)	4,878	4,538	12,621
Preferred units, as if converted to Class A common units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per unit (in shares)	0	0	9,950
Incentive units—Class B common units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per unit (in shares)	0	0	2,671
Outstanding stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per unit (in shares)	4,243	3,121	0
Unvested RSAs
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per unit (in shares)	361	742	0
Unvested RSUs
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per unit (in shares)	274	675	0

Employee Savings Plan (Details)

Employee Savings Plan (Details)	12 Months Ended
	Dec. 31, 2021USD ($)
Retirement Benefits [Abstract]
Matching contributions made by employer for savings plan	$ 991,500

Related Party Disclosures (Deta

Related Party Disclosures (Details) - USD ($)	Jun. 01, 2020	Dec. 21, 2017	Dec. 31, 2021	Dec. 31, 2021	Dec. 31, 2020
Related Party Transaction [Line Items]
Number of shares acquired (in shares)			0	0	0
Zentera Sublicenses
Related Party Transaction [Line Items]
Contra-research and development expense			$ 5,300,000
Capital Addition Purchase Commitments
Related Party Transaction [Line Items]
Equipment purchase and sale agreement	$ 400,000
Affiliated Entity | License Agreement
Related Party Transaction [Line Items]
Payments incurred				$ 10,000,000	$ 0
Affiliated Entity | Master Services Agreement
Related Party Transaction [Line Items]
Due to related parties			0	0	0
Affiliated Entity | Equipment Purchase and Sale Agreement
Related Party Transaction [Line Items]
Due to related parties			0	0	0
Director | Master Services Agreement
Related Party Transaction [Line Items]
Due to related parties			$ 1,000,000	$ 1,000,000	$ 0
VIE, Primary Beneficiary | Kalyra Pharmaceuticals, Inc.
Related Party Transaction [Line Items]
Share price (in dollars per share)		$ 0.26
Cash payments to acquire interest		$ 4,500,000
Agreement term (in years)				15 years
VIE, Primary Beneficiary | Series B Preferred Units | Kalyra Pharmaceuticals, Inc.
Related Party Transaction [Line Items]
Number of shares acquired (in shares)		17,307,692

Selected Quarterly Financial _3

Selected Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating Expenses
Research and development	$ 38,439	$ 53,998	$ 44,770	$ 38,394	$ 29,521	$ 24,670	$ 17,452	$ 13,258	$ 175,601	$ 84,901	$ 38,386
General and administrative	9,754	8,872	10,362	11,953	10,724	10,097	9,924	3,141	40,941	33,886	8,459
Total operating expenses	48,193	62,870	55,132	50,347	40,245	34,767	27,376	16,399	216,542	118,787	46,845
Loss from operations	(48,193)	(62,870)	(55,132)	(50,347)	(40,245)	(34,767)	(27,376)	(16,399)	(216,542)	(118,787)	(46,845)
Other Income (Expense)
Investment and other income, net	88	99	115	99	315	120	84	164	401	683	482
Gain on deconsolidation of Zentera	0	51,582	0	0					51,582	0	0
Net loss before income taxes	(48,105)	(11,189)	(55,017)	(50,248)	(39,930)	(34,647)	(27,292)	(16,235)	(164,559)	(118,104)	(46,363)
Income tax expense (benefit)	159	(697)	45	196	426	18	0	0	(297)	444	15
Loss on equity method investment	1,831	0	0	0					1,831	0	0
Net loss	(50,095)	(10,492)	(55,062)	(50,444)	(40,356)	(34,665)	(27,292)	(16,235)	(166,093)	(118,548)	(46,378)
Net loss attributable to noncontrolling interests	(36)	(6,301)	(488)	(543)	(53)	(110)	(435)	(109)	(7,368)	(707)	(715)
Net loss attributable to Zentalis	$ (50,059)	$ (4,191)	$ (54,574)	$ (49,901)	$ (40,303)	$ (34,555)	$ (26,857)	$ (16,126)	$ (158,725)	$ (117,841)	$ (45,663)
Net loss per common share/Class A common unit outstanding, basic (in dollars per share)	$ (1.11)	$ (0.09)	$ (1.34)	$ (1.24)	$ (1.01)	$ (0.91)	$ (0.78)	$ (2.88)
Net loss per common share/Class A common unit outstanding, diluted (in dollars per share)	$ (1.11)	$ (0.09)	$ (1.34)	$ (1.24)	$ (1.01)	$ (0.91)	$ (0.78)	$ (2.88)	$ 0	$ 0	$ (8.16)
Common shares/units used in computing less loss per share/Class A common unit, basic (in shares)	44,976,000	44,609,000	40,738,000	40,359,000	39,936,000	37,959,000	34,353,000	5,601,000	42,688,000	28,113,000	5,597,000
Common shares/units used in computing less loss per share/Class A common unit, diluted (in shares)	44,976,000	44,609,000	40,738,000	40,359,000	39,936,000	37,959,000	34,353,000	5,601,000	42,688,000	28,113,000	5,597,000