Geographic Information, Product Groups and Customer Concentration - Revenues by Product Group (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2018	Mar. 31, 2018	Dec. 30, 2017	Sep. 30, 2017	Jul. 01, 2017	Apr. 01, 2017	Dec. 31, 2016	Oct. 01, 2016	Jun. 30, 2018	Jul. 01, 2017	Jul. 02, 2016
Revenue from External Customer [Line Items]
Revenues	$ 120,944	$ 127,293	$ 139,335	$ 155,598	$ 149,380	$ 162,182	$ 153,914	$ 135,492	$ 543,170	$ 600,968	$ 407,914
100 Gb/s transmission modules
Revenue from External Customer [Line Items]
Revenues									422,699	457,975	228,619
40 Gb/s and lower transmission modules
Revenue from External Customer [Line Items]
Revenues									$ 120,471	$ 142,993	$ 179,295