Cover page - USD ($)	12 Months Ended
Cover page - USD ($)	Dec. 31, 2021	Mar. 07, 2022	Jun. 30, 2021
Cover [Abstract]
Document Type	10-K/A
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	001-36570
Entity Registrant Name	ZOSANO PHARMA CORPORATION
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	45-4488360
Entity Address, Address Line One	34790 Ardentech Court
Entity Address, City or Town	Fremont
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94555
City Area Code	510
Local Phone Number	745-1200
Title of 12(b) Security	Common stock, par value $0.0001 per share
Trading Symbol	ZSAN
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Auditor Attestation Flag	false
Entity Public Float			$ 104,972,443
Entity Common Stock, Shares Outstanding		4,902,260
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCE None. EXPLANATORY NOTE This Amendment No. 1 to Form 10-K (the "Amendment") amends the Annual Report on Form 10-K for the fiscal year ended December 31, 2021 originally filed on March 17, 2022 (the "Original Filing") by Zosano Pharma Corporation. We are filing this Amendment to present the information required by Items 10, 11, 12, 13 and 14 of Part III of Form 10-K because a definitive proxy statement containing such information will not be filed within 120 days after the end of our fiscal year covered by the Original Filing. This Amendment is being filed solely to: •amend and restate in its entirety Items 10, 11, 12, 13 and 14 of Part III to include the information required by such Items; •delete the reference on the cover of the Original Filing to the incorporation by reference of portions of our proxy statement into Part III of the Original Filing; •amend and restate in its entirety the Exhibit Index in Item 15 of Part IV of the Original Filing; and •file new certifications ("Certifications") of our principal executive officer and principal financial officer as exhibits to this Amendment under Item 15 of Part IV, pursuant to Section 302 of the Sarbanes-Oxley Act of 2002 and Rule 12b-15 under the Securities Exchange Act of 1934, as amended. Because no financial statements have been included in this Amendment and this Amendment does not contain or amend any disclosure with respect to Items 307 and 308 of Regulation S-K, paragraphs 3, 4 and 5 of the Certifications have been omitted. We are not including the certifications under Section 906 of the Sarbanes-Oxley Act of 2002 as no financial statements are being filed with this Amendment. Except as expressly set forth herein, this Amendment does not reflect events occurring after the date of the Original Filing or modify or update disclosure in, or exhibits to, the Original Filing. Furthermore, this Amendment does not change any previously reported financial results. Information not affected by the Amendment remains unchanged and reflects the disclosures made at the time the Original Filing was made. Accordingly, this Amendment should be read in conjunction with the Original Filing and our other filings with the Securities and Exchange Commission. References in this Amendment to the terms “Zosano”, the “Company”, “we”, “our” and “us” refer to Zosano Pharma Corporation.
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Entity Central Index Key	0001587221

Zosano Pharma Corp 10-K/A