Asset sale (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
	Jan. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Assets held for sale			$ 13,953
Reclassification from assets held-for-sale		$ 3,400
Contingent liability		(6,700)
Gain within operating income		2,000
Inventories | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Assets held for sale, other			13,100
Property, plant and equipment | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Assets held for sale, other			$ 800
Optoelectronics Components Co. Ltd.
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from post-closing transaction services fees under transition services agreement	$ 1,400
Optoelectronics Components Co. Ltd. | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Consideration received pursuant to asset purchase agreement	25,000
Optoelectronics Components Co. Ltd. | Adjusted consideration | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Disposal group consideration adjustment	21,600
Optoelectronics Components Co. Ltd. | Other adjustments to consideration for potential indemnification claims | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Disposal group consideration adjustment	10,000
Optoelectronics Components Co. Ltd. | Assets held for sale | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Assets sold	12,800
Optoelectronics Components Co. Ltd. | Inventories
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Consideration received pursuant to asset purchase agreement	12,100
Optoelectronics Components Co. Ltd. | Inventories | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Assets sold	12,100
Optoelectronics Components Co. Ltd. | Property, plant and equipment | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Assets sold	$ 700
Other current liabilities | Indemnification agreement
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Contingent liability		6,700
Property, plant and equipment | Indemnification agreement
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Contingent liability		$ 200