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Income tax holiday tax rate.

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Income Taxes [Line Items]

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to changes in the income tax rates.

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Amount of income tax expense (benefit) from continuing operations attributable to an adjustment of a deferred tax liability or asset for enacted changes in tax laws or rates or a change in the tax status of the entity.

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Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to repatriation of foreign earnings.

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Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.

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The amount of the tax credit carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.

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Amount of undistributed earnings of foreign subsidiaries intended to be permanently reinvested outside the country of domicile.

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Amount of unrecognized tax benefits.

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Amount accrued for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return.

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Amount of increase in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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Amount of increase (decrease) in the valuation allowance for a specified deferred tax asset.

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Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes [Line Items]
U.S. federal corporate income tax rate	21.00%	35.00%	35.00%
Adjustment to provisional tax benefit	$ 625,000
Increase of effective tax rate	0.40%
Additional deferred tax provision	$ 2,614	$ 22,345
Gross tax research other tax credit carryforwards	29,858,000
Accrued interest on unrecognized tax benefits	568,000	327,000	$ 491,000
Gross unrecognized tax benefits excluding interest and penalties	32,684,000	27,345,000	25,465,000	$ 4,332,000
Net unrecognized tax benefits, excluding interest and penalties, related to foreign tax positions	2,150,000
Change in valuation allowance	4,307,000	1,102,000	$ 6,400,000
Undistributed earnings of foreign subsidiaries	521,000,000	560,000,000
Tax expense related to repatriation of foreign earnings	$ 4,624,000	$ 27,610,000
Minimum [Member]
Income Taxes [Line Items]
Income tax holiday tax rate	7.50%
Maximum [Member]
Income Taxes [Line Items]
Income tax holiday tax rate	16.00%
Indefinite [Member]
Income Taxes [Line Items]
Gross tax research other tax credit carryforwards	$ 15,081,000
Federal State and Foreign [Member]
Income Taxes [Line Items]
Tax credit expiration period	2035
Federal State and Foreign [Member] \| Indefinite [Member]
Income Taxes [Line Items]
Operating loss carry forwards	$ 36,057,000
Federal State and Foreign [Member] \| 2017 [Member]
Income Taxes [Line Items]
Operating loss carry forwards	$ 43,715,000