Stock Option Plan - Stock Options Activity (Details) $ / shares in Units, $ in Thousands	6 Months Ended
	Feb. 29, 2020 USD ($) $ / shares shares	Feb. 23, 2019 USD ($)
Additional disclosures
Proceeds from option exercises | $	$ 931	$ 361
Stock Options
Shares
Outstanding at beginning of period (in shares) | shares	2,748,735
Granted (in shares) | shares	194,014
Exercised (in shares) | shares	(76,366)
Forfeited (in shares) | shares	0
Outstanding at end of period (in shares) | shares	2,866,383
Options vested or expected to vest (in shares) | shares	2,866,383
Exercisable (in shares) | shares	1,520,073
Weighted average exercise price
Outstanding at beginning of period (in dollars per share) | $ / shares	$ 13.35
Granted (in dollars per share) | $ / shares	24.20
Exercised (in dollars per share) | $ / shares	12.20
Forfeited (in dollars per share) | $ / shares	0
Outstanding at end of period (in dollars per share) | $ / shares	14.11
Options vested or expected to vest (in dollars per share) | $ / shares	14.11
Exercisable (in dollars per share) | $ / shares	$ 12.69
Weighted average remaining contractual term
Outstanding at end of period, weighted average remaining contractual life	7 years 9 months 7 days
Vested and expected to vest at end of period, weighted average remaining contractual life	7 years 9 months 7 days
Exercisable at end of period, weighted average remaining contractual life	7 years 6 months
Additional disclosures
Unrecognized compensation costs | $	$ 4,300
Period for recognition of unrecognized compensation cost	1 year 29 days
Proceeds from option exercises | $	$ 900