Significant Accounting Policies and Disclosures - Additional Information (Details)	12 Months Ended
	May 28, 2022 USD ($) Number $ / shares shares	May 29, 2021 USD ($) $ / shares shares	May 30, 2020 USD ($) $ / shares shares
Allowance for doubtful accounts	$ 186,000	$ 202,000
Foreign exchange (gain) loss	273,000	759,000	$ (15,000)
Finished goods	66,600,000	57,000,000.0
Raw material	8,000,000.0	3,900,000
Work in progress	5,800,000	2,600,000
Inventory valuation reserves	6,100,000	5,900,000
Inventory provisions	462,000	1,041,000	1,013,000
Investments - current	5,000,000	0
Depreciation	3,200,000	3,200,000	3,100,000
Construction in progress	1,991,000	1,429,000
Other non-current liabilities	766,000	1,366,000
Share-based compensation expense	$ 654,000	675,000	$ 683,000
Stock option vesting period	5 years
Option terms to exercise	10 years
Exercised | shares	373,489
Proceeds from share exercised	$ 3,000,000.0
Intrinsic value	$ 1,900,000	$ 100,000
Weighted average fair value of stock option grants | $ / shares	$ 1.50	$ 0.49	$ 0.81
Total unrecognized compensation costs	$ 900,000
Total grant date fair value stock options vested	$ 200,000
Limit of cash dividends Class B common stock (percent)	90.00%
Common stock options anti-dilutive | shares	0	0	1,120,000
Common Stock
Common stock shares, authorized | shares	17,000,000
Common Class B
Common stock shares, authorized | shares	3,000,000
Number of votes per share | Number	10
Employees' 2011 Long-Term Incentive Compensation Plan
Number of shares authorized | shares	3,500,000
Number of shares for future issuance | shares	1,302,000
Option exercisable period	5 years
Manufacturing Facilities
Construction in progress	$ 1,000,000.0
Healthcare
Construction in progress	500,000
IT systems
Construction in progress	$ 300,000
Maximum
Services revenue recognized as percentage of aggregate revenue	5.00%
Intrinsic value			$ 100,000
Period of recognition	4 years
Maximum | Employees' 2011 Long-Term Incentive Compensation Plan
Option terms to exercise	10 years
Minimum
Period of recognition	2 years