Net Income Per Common Share Attributable to Alpha and Omega Semiconductor Limited - Basic and Diluted Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2021	Dec. 31, 2020
Numerator:
Net income attributable to Alpha and Omega Semiconductor Limited	$ 382,998	$ 12,903	$ 406,422	$ 22,477
Basic:
Weighted average number of common shares used to compute basic net income per share	26,593	25,672	26,479	25,506
Effect of potentially dilutive securities:
Stock options, RSUs and ESPP shares	1,694	1,681	1,484	1,328
Weighted average number of common shares used to compute diluted net income per share	28,287	27,353	27,963	26,834
Net income per share attributable to Alpha and Omega Semiconductor Limited:
Basic (in dollars per share)	$ 14.40	$ 0.50	$ 15.35	$ 0.88
Diluted (in dollars per share)	$ 13.54	$ 0.47	$ 14.53	$ 0.84