Consolidated Statements of Shareholders’ Equity - USD ($) shares in Thousands, $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Treasury	Paid-In Capital	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment
Beginning Balance (in shares) at Aug. 29, 2018			30,003	(500)
Beginning Balance at Aug. 29, 2018	$ 112,628	$ 2,479	$ 9,602	$ (4,775)	$ 33,872	$ 73,929	$ 2,479
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss for the year	(15,226)					(15,226)
Common stock issued under nonemployee director benefit plans (in shares)			53
Common stock issued under nonemployee director benefit plans			$ 17		(17)
Common stock issued under employee benefit plans (in shares)			93
Common stock issued under employee benefit plans			$ 30		(30)
Share-based compensation expense (in shares)			329
Share-based compensation expense	1,149		$ 104		1,045
Ending Balance (in shares) at Aug. 28, 2019			30,478	(500)
Ending Balance at Aug. 28, 2019	$ 101,030	$ 1,027	$ 9,753	$ (4,775)	34,870	61,182	$ 1,027
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accounting standards update	us-gaap:AccountingStandardsUpdate201602Member
Net loss for the year	$ (29,450)					(29,450)
Common stock issued under nonemployee director benefit plans (in shares)			64
Common stock issued under nonemployee director benefit plans			$ 20		(20)
Common stock issued under employee benefit plans (in shares)			73
Common stock issued under employee benefit plans	(42)		$ 24		(66)
Share-based compensation expense (in shares)			509
Share-based compensation expense	1,034		$ 163		871
Ending Balance (in shares) at Aug. 26, 2020			31,124	(500)
Ending Balance at Aug. 26, 2020	$ 73,599		$ 9,960	$ (4,775)	$ 35,655	$ 32,759