Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Tax Credit Carryforward [Line Items]
U.S. federal corporate tax rate			35.00%	35.00%	35.00%
Net tax expense related to the Tax Act	$ 45,908,000
Additional income taxes on undistributed foreign earnings	0		$ 0
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	30,581,000		$ 30,581,000	$ 28,849,000	$ 26,503,000	$ 19,488,000
Unrecognized tax benefits, if recognized, would affect the effective tax rate	27,200,000		$ 27,200,000
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 2012. 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, 2017, 2016 and 2015.
Net deferred tax assets	18,569,000		$ 18,569,000	41,422,000
Tax credit carryforward, valuation allowance	13,000,000		13,000,000	22,400,000
Operating loss carryforward [Abstract]
Operating loss carryforwards, valuation allowance	5,000,000		5,000,000	5,900,000
Income taxes supplemental information [Abstract]
Statutory accounting practices, retained earnings not available for dividends	51,000		51,000
Additional tax on undistributed foreign earnings	42,000		42,000
Tax holidays			$ 3,700,000	$ 7,300,000	$ 2,900,000
Tax holidays basic EPS			$ 0.08	$ 0.15	$ 0.06
Tax holidays diluted EPS			$ 0.08	$ 0.15	$ 0.06
China
Income taxes supplemental information [Abstract]
Deferred tax liabilities, undistributed foreign earnings	429,000		$ 429,000
State and Local Jurisdiction
Operating loss carryforward [Abstract]
Operating loss carryforwards	3,000,000		$ 3,000,000
Operating loss carryforwards, expiration dates			Jan. 01, 2018
Foreign Tax Authority
Operating loss carryforward [Abstract]
Operating loss carryforwards	2,000,000		$ 2,000,000
Operating loss carryforwards, expiration dates			Jan. 01, 2020
Income taxes supplemental information [Abstract]
Deferred tax liabilities, undistributed foreign earnings	770,000		$ 770,000
Federal
Tax Credit Carryforward [Line Items]
Tax credit carryforward, amount	20,000,000		$ 20,000,000
Tax credit carryforward, expiration dates			Jan. 01, 2021
Research
Tax Credit Carryforward [Line Items]
Tax credit carryforward, amount	7,000,000		$ 7,000,000
Tax credit carryforward, expiration dates			Jan. 01, 2020
ASU No. 2013-11
Tax Credit Carryforward [Line Items]
Deferred tax assets operating loss carryforwards	3,200,000		$ 3,200,000	$ 13,600,000
Deferred tax assets excluding tax benefits for operating loss carryforwards	$ 15,400,000		15,400,000	$ 27,800,000
ASU No. 2016-09
Tax Credit Carryforward [Line Items]
Increase in income tax expense			1,500,000
ASU No. 2016-09 | Adoption Related to Income Tax Components
Tax Credit Carryforward [Line Items]
Increase (decrease) in retained earnings due to effect on adoption			$ 4,800,000
Scenario, Forecast
Tax Credit Carryforward [Line Items]
U.S. federal corporate tax rate		21.00%