Commitments and Contingencies (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		9 Months Ended
	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020	Sep. 30, 2020	Sep. 30, 2021	Dec. 31, 2020	Dec. 31, 2019	Aug. 31, 2017
Tunable lasers
Loss Contingencies [Line Items]
Non-cancelable purchase order commitment					$ 1.5	$ 1.6
Non-cancelable purchase order delivery period		12 months
Non-cancelable purchase order commitment remaining					$ 1.7
High speed optical receivers business | Disposed of by Sale
Loss Contingencies [Line Items]
Escrow deposits related to indemnity claims							$ 2.5
Amount of the escrow balance received	$ 0.6		$ 1.5
Loss on sale of discontinued operations				$ 1.4
High speed optical receivers business | Disposed of by Sale | Macom
Loss Contingencies [Line Items]
Amount of the escrow balance received	$ 1.9
Macom | High speed optical receivers business | Disposed of by Sale
Loss Contingencies [Line Items]
Escrow deposits related to indemnity claims								$ 4.0