Diluted Earnings Per Share - Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Feb. 28, 2021	Nov. 29, 2020	Aug. 30, 2020	Feb. 23, 2020	Nov. 24, 2019	Aug. 25, 2019	Feb. 28, 2021	Feb. 23, 2020
Numerator:
Net (loss) income	$ (5,498)	$ (13,301)	$ (11,000)	$ (11,518)	$ (6,740)	$ (4,784)	$ (29,799)	$ (23,042)
Denominator:
Weighted average shares for basic net loss per share (in shares)	29,323			29,170			29,282	29,155
Effect of dilutive securities:
Stock options and restricted stock units (in shares)	0			0			0	0
Weighted average shares for diluted net loss per share (in shares)	29,323			29,170			29,282	29,155
Diluted net loss per share (in dollars per share)	$ (0.19)			$ (0.39)			$ (1.02)	$ (0.79)