Asset sale (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Jan. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Apr. 30, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Restructuring charges		$ 261	$ 3,135	$ 3,934
Assets held for sale		0	2,971
Gain within operating income		903	(200)	2,193
Warranty reserve		6,700
Joint Stock Company Rusnano
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Accrued payment derivative, amount			$ 2,000
Disposal Group, Disposed of by Sale, Not Discontinued Operations | APAT OE
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration received pursuant to asset purchase agreement	$ 25,000
Gain within operating income				$ 2,200
Proceeds from post-closing transaction services fees under transition services agreement	$ 1,400
Receivables		11,900
Payables		$ 11,800
NeoPhotonics Corporation, LLC | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percent of interest to be disposed			100.00%
Restructuring charges			$ 1,600
Assets held for sale			$ 3,000
Ownership interest disposed					100.00%
Consideration received pursuant to asset purchase agreement					$ 2,000
Exit fee settlements					$ 2,000