Summary of Significant Accounting Policies - Additional Information (Details) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 30, 2019 USD ($) Customer	Mar. 31, 2018 USD ($) Customer	Dec. 29, 2018 Customer	Dec. 30, 2018 USD ($)
Disclosure Summary Of Significant Accounting Policies [Line Items]
Extended product warranty period	1 year
Extended warranty, period to determine nature of sale	60 days
Deferred revenue recognized	$ 400	$ 500
Products warranty period	2 years
Right-of-use assets	$ 3,678			$ 4,000
Lease liabilities	$ 4,202			4,500
Deferred rent related to operating lease				$ 500
Revenue, Total | Customer Concentration Risk
Disclosure Summary Of Significant Accounting Policies [Line Items]
Number of customers | Customer	0	0
Accounts Receivable | Credit Concentration Risk
Disclosure Summary Of Significant Accounting Policies [Line Items]
Number of customers | Customer	1		0
Percentage of accounts receivable accounted	12.00%
Royalty Agreements
Disclosure Summary Of Significant Accounting Policies [Line Items]
Number of customers | Customer	2
IQ 532/577 Laser Consoles
Disclosure Summary Of Significant Accounting Policies [Line Items]
Products warranty period	5 years