Organization and Business	3 Months Ended
Organization and Business	Mar. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Business	Organization and Business Organization Zentalis Pharmaceuticals, LLC (“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 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 incentive 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. Zentalis Pharmaceuticals, LLC is a Delaware limited liability company. The Company manages its operations as a single segment for the purposes of assessing performance and making operating decisions. To date, all of the Company’s revenue has been generated in the United States. All of the Company’s tangible assets are held in the United States. 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 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. Liquidity Substantial doubt about an entity’s ability to continue as a going concern exists when relevant conditions and events, considered in the aggregate, indicate that it is probable that the entity will be unable to meet its obligations as they become due within one year from the financial statement issuance date. The Company determined that there are no conditions or events that raise substantial doubt about its ability to continue as a going concern within one year after the date that the interim unaudited condensed consolidated financial statements for the quarter ended March 31, 2020 are issued.