Revenue - Additional Information (Detail)	3 Months Ended
	Mar. 30, 2019 USD ($) Installment	Dec. 29, 2018 USD ($)
Revenue From Contract With Customers [Line Items]
Revenue remaining performance obligation	$ 102,600,000
Revenue performance obligation, description of timing	We expect to recognize approximately 69% of our remaining performance obligations as revenue in 2019, and the balance in 2020.
TFE
Revenue From Contract With Customers [Line Items]
Contract liabilities	$ 11,048,000	$ 14,947,000
Revenue remaining performance obligation	$ 59,300,000
TFE | Accounts Receivable, Unbilled
Revenue From Contract With Customers [Line Items]
Number of installments | Installment	3
Change in contract assets	$ 383,000
TFE | Customer Advances
Revenue From Contract With Customers [Line Items]
Contract with customer liability revenue recognized	6,500,000
Contract liabilities	10,335,000	14,314,000
TFE | Deferred Revenue
Revenue From Contract With Customers [Line Items]
Contract with customer liability revenue recognized	209,000
Contract liabilities	713,000	633,000
Photonics
Revenue From Contract With Customers [Line Items]
Change in contract assets	1,042,000
Revenue remaining performance obligation	43,300,000
Photonics | Accounts Receivable, Unbilled
Revenue From Contract With Customers [Line Items]
Change in contract assets	1,068,000
Photonics | Deferred Revenue
Revenue From Contract With Customers [Line Items]
Contract with customer liability revenue recognized	317,000
Contract liabilities	$ 784,000	$ 1,101,000