Net Income (Loss) Per Share - Basic and Diluted Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016
Numerator:
Net income (loss) attributable to Alpha and Omega Semiconductor Limited	$ 3,556	$ (1,263)	$ 9,710	$ (4,849)
Basic:
Weighted average number of common shares used to compute basic net income (loss) per share	23,675	22,232	23,396	22,400
Effect of potentially dilutive securities:
Stock options, RSUs and ESPP shares	1,276	0	1,385	0
Weighted average number of common shares used to compute diluted net income (loss) per share	24,951	22,232	24,781	22,400
Net income (loss) per share attributable to Alpha and Omega Semiconductor Limited:
Basic (in dollars per share)	$ 0.15	$ (0.06)	$ 0.42	$ (0.22)
Diluted (in dollars per share)	$ 0.14	$ (0.06)	$ 0.39	$ (0.22)