Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets
Inventory cost	$ 10,423	$ 7,974
Accrued expenses and accounts receivable	4,420	1,866
Foreign tax credits	5,848	17,600
Research and development tax credits	16,263	15,456
Net operating loss carryforwards	24,139	9,635
Lease obligations	3,773
Accrued pension	4,629	4,294
Share based compensation and others	7,805	9,972
Total deferred tax assets, include valuation allowance	77,300	66,797
Valuation allowances	(29,414)	(25,941)
Total deferred tax assets, non-current	47,886	40,856
Deferred tax liabilities
Plant, equipment and intangible assets	(13,816)	(16,661)
Right of use assets	(4,008)
Outside basis differences and others	(23,648)	(7,267)
Total deferred tax liabilities, non-current	(41,472)	(23,928)
Net deferred tax assets	$ 6,414	$ 16,928