Document And Entity Information - shares	3 Months Ended
	Sep. 30, 2015	Nov. 06, 2015
Entity Registrant Name	Biota Pharmaceuticals, Inc.
Entity Central Index Key	0000072444
Trading Symbol	bota
Current Fiscal Year End Date	--06-30
Entity Filer Category	Accelerated Filer
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	No
Entity Common Stock, Shares Outstanding (in shares)		38,636,946
Document Type	10-Q
Document Period End Date	Sep. 30, 2015
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	Q1
Amendment Flag	false