Net Income (Loss) Per Common Share Attributable to Alpha and Omega Semiconductor Limited - Potential Dilutive Shares (Details) - shares shares in Thousands	12 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2023
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Incremental common shares attributable to dilutive effect of share-based payment arrangements (USD per share)	0	0	1,976
Potential dilutive securities (in shares)	3,104	3,841	619
Employee stock options and RSUs
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities (in shares)	2,475	2,822	310
Employee Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities (in shares)	629	1,019	309