BASIS OF PREPARATION - Merger (Details) $ / shares in Units, $ in Thousands		3 Months Ended		9 Months Ended
	Mar. 11, 2018 USD ($) d $ / shares	Mar. 31, 2018 USD ($) $ / shares	Apr. 01, 2017 USD ($)	Mar. 31, 2018 USD ($) $ / shares	Apr. 01, 2017 USD ($)	Jul. 01, 2017 $ / shares
Business Combination, Separately Recognized Transactions [Line Items]
Cash consideration paid per cancelled share of Oclaro stock (in USD per share)	$ 5.60
Common stock, par value (in usd per share)		$ 0.01		$ 0.01		$ 0.01
Increase in cash consideration per share included in Exchange ratio if threshold shares attained (in USD per share)	$ 68.975
Trading Days Included in Average Closing Price | d	10
Amount payable if Oclaro terminates the Merger Agreement | $	$ 63,000
Amount receivable if Lumentum terminates the Merger Agreement | $	$ 80,000
Restructuring, acquisition and related (income) expense, net | $		$ 3,084	$ (301)	$ 3,084	$ 92
Lumentum
Business Combination, Separately Recognized Transactions [Line Items]
Conversion ratio of new shares to Company shares	0.0636
Common stock, par value (in usd per share)	$ 0.001
Merger consideration shares as percent of total pre-merger shares that would trigger an increase of the purchase price per share (percent)	19.90%