Commitments and Contingencies - Additional Information (Details) $ in Millions		3 Months Ended			12 Months Ended
	Jul. 31, 2018 USD ($)	Sep. 30, 2019 USD ($)	Dec. 31, 2018 purchase_order	Mar. 31, 2018 USD ($) purchase_order	Dec. 31, 2019 USD ($)	Aug. 31, 2017 USD ($)
Commitments and Contingencies Disclosure [Line Items]
Number of non-cancelable purchase orders executed | purchase_order			1	1
Minimum royalty payable					$ 0.2
Tunable Lasers
Commitments and Contingencies Disclosure [Line Items]
Non-cancelable purchase order delivery period (in months)		18 months
Non-cancelable purchase order commitment		$ 1.9		$ 1.1
Non-cancelable purchase order commitment remained					1.3
Macom
Commitments and Contingencies Disclosure [Line Items]
Accounts receivable				$ 2.1
Disposed of by Sale | HSOR | Macom
Commitments and Contingencies Disclosure [Line Items]
Escrow deposits related to indemnity claims					2.5	$ 4.0
Amount of the escrow balance received					$ 1.5
Disposed of by Sale | Opto
Commitments and Contingencies Disclosure [Line Items]
Contingent consideration	$ 1.0
Non-cancelable purchase order delivery period (in months)	18 months