Income Taxes - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Tax Credit Carryforward [Line Items]
U.S. federal corporate tax rate		21.00%	35.00%	35.00%
Adjustment to tax expense related to the Tax Act	$ 2,762
Transition tax on foreign earnings adjustment	2,815
Foreign tax credits used to offset transition tax adjustments	4,625
Other adjustments on effect of change	753	$ 800
Significant change in unrecognized tax benefits, nature of event		It is reasonably possible that the amount of the unrecognized benefit with respect to certain of our unrecognized tax positions will significantly increase or decrease within the next 12 months.
Significant change in unrecognized tax benefits is reasonably possible, estimated range not possible		These changes may be the result of settlements of ongoing audits or competent authority proceedings. At this time, an estimate of the range of the reasonably possible outcomes cannot be made.
Unrecognized tax benefits	32,209	$ 32,209	$ 30,581	$ 28,849	$ 26,503
Unrecognized tax benefits, if recognized, would affect the effective tax rate	28,800	$ 28,800
Income tax examination, description		We file income tax returns in the U.S. federal jurisdiction and in various state and foreign jurisdictions. We are no longer subject to U.S. federal income tax examinations by tax authorities for tax years before 2008, or for the 2010 and 2011 tax years. We are no longer subject to China income tax examinations by tax authorities for tax years before 2007. With respect to state and local jurisdictions and countries outside of the U.S., with limited exceptions, we are no longer subject to income tax audits for years before 2013. Although the outcome of tax audits is always uncertain, we believe that adequate amounts of tax, interest and penalties, if any, have been provided for in our reserve for any adjustments that may result from future tax audits. We recognize accrued interest and penalties, if any, related to unrecognized tax benefits in interest expense. We had an immaterial amount of accrued interest and penalties at December 31, 2018, 2017 and 2016.
Net deferred tax assets	16,928	$ 16,928	18,569
Tax credit carryforward, valuation allowance	19,000	19,000	13,000
Operating loss carryforward [Abstract]
Operating loss carryforwards, valuation allowance	7,000	7,000	5,000
Income taxes supplemental information [Abstract]
Statutory accounting practices, retained earnings not available for dividends	55	55
Additional tax on undistributed foreign earnings	37	37
Tax holidays		$ 1,600	$ 3,700	$ 7,300
Tax holidays basic EPS		$ 0.0	$ 0.08	$ 0.15
Tax holidays diluted EPS		$ 0.03	$ 0.08	$ 0.15
China
Income taxes supplemental information [Abstract]
Deferred tax liabilities, undistributed foreign earnings	381	$ 381
State and Local Jurisdiction
Operating loss carryforward [Abstract]
Operating loss carryforwards	3,000	$ 3,000
Operating loss carryforwards, expiration dates		Jan. 01, 2019
Foreign Tax Authority
Operating loss carryforward [Abstract]
Operating loss carryforwards	34,000	$ 34,000
Operating loss carryforwards, expiration dates		Jan. 01, 2020
Income taxes supplemental information [Abstract]
Deferred tax liabilities, undistributed foreign earnings	742	$ 742
Federal
Tax Credit Carryforward [Line Items]
Tax credit carryforward, amount	26,000	$ 26,000
Tax credit carryforward, expiration dates		Jan. 01, 2026
Research
Tax Credit Carryforward [Line Items]
Tax credit carryforward, amount	8,000	$ 8,000
Tax credit carryforward, expiration dates		Jan. 01, 2020
ASU No. 2013-11
Tax Credit Carryforward [Line Items]
Deferred tax assets operating loss carryforwards	3,200	$ 3,200
Deferred tax assets excluding tax benefits for operating loss carryforwards	$ 13,700	$ 13,700