Cover - shares	9 Months Ended
	Mar. 31, 2021	Apr. 23, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2021
Document Transition Report	false
Entity File Number	001-34717
Entity Registrant Name	Alpha and Omega Semiconductor Limited
Entity Incorporation, State or Country Code	D0
Entity Tax Identification Number	77-0553536
Entity Address, Address Line One	Clarendon House
Entity Address, Address Line Two	2 Church Street
Entity Address, City or Town	Hamilton
Entity Address, Postal Zip Code	HM 11
Entity Address, Country	BM
City Area Code	408
Local Phone Number	830-9742
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Title of 12(b) Security	Common Shares
Trading Symbol	AOSL
Security Exchange Name	NASDAQ
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		26,091,190
Entity Central Index Key	0001387467
Current Fiscal Year End Date	--06-30
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Amendment Flag	false