Revenue Recognition - Additional Information (Detail) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 28, 2019 USD ($) Customer	Dec. 28, 2018 Customer
Accrued Expenses [Member]
Concentration Risk [Line Items]
Unpaid customer rebates | $	$ 0.3
Maximum [Member]
Concentration Risk [Line Items]
Product warranty period (in years)	2 years
Customer Concentration Risk [Member] | Lam Research Corporation, Applied Materials, Inc. and ASM International, Inc. [Member]
Concentration Risk [Line Items]
Number of customers with accounts receivable greater than 10% | Customer	3	3
Customer Concentration Risk [Member] | Lam Research Corporation, Applied Materials, Inc. and ASM International, Inc. [Member] | Accounts Receivable
Concentration Risk [Line Items]
Concentration percentage	62.30%	62.90%