v3.22.0.1

Cover	Feb. 23, 2022
Cover [Abstract]
Document Type	8-K
Document Period End Date	Feb. 23, 2022
Entity Registrant Name	Arena Pharmaceuticals, Inc.
Entity Incorporation, State or Country Code	DE
Entity File Number	000-31161
Entity Tax Identification Number	23-2908305
Entity Address, Address Line One	136 Heber Avenue
Entity Address, Address Line Two	Suite 204
Entity Address, City or Town	Park City
Entity Address, State or Province	UT
Entity Address, Postal Zip Code	84060
City Area Code	858
Local Phone Number	453-7200
Written Communications	false
Soliciting Material	false
Pre-commencement Tender Offer	false
Pre-commencement Issuer Tender Offer	false
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Trading Symbol	ARNA
Security Exchange Name	NASDAQ
Entity Emerging Growth Company	false
Entity Central Index Key	0001080709
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The type of document being provided (such as 10-K, 10-Q, 485BPOS, etc). The document type is limited to the same value as the supporting SEC submission type, or the word 'Other'.

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A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Commission file number. The field allows up to 17 characters. The prefix may contain 1-3 digits, the sequence number may contain 1-8 digits, the optional suffix may contain 1-4 characters, and the fields are separated with a hyphen.

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Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as written communications pursuant to Rule 425 under the Securities Act.

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ARENA PHARMACEUTICALS INC 8-K