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Income Taxes - Additional Information (Detail) - USD ($) | 3 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Dec. 31, 2017 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014
Income Tax Disclosure [Line Items] |  |  |  |  |
Tax cuts and jobs act, incomplete accounting, estimated income tax expense | $ 11,900,000 |  |  |  |
Tax cuts and jobs act, incomplete accounting, estimated write-down of deferred tax assets | 9,200,000 |  |  |  |
Tax cuts and jobs act, incomplete accounting, change in tax rate estimate income tax expense related to unrepatriated foreign earnings | 2,700,000 |  |  |  |
Deferred tax benefit recorded as an adjustment to other comprehensive income |  | $ 1,700,000 | $ 1,500,000 |  |
Foreign and domestic carry-forwards, unamortized research and development cost and state credit carry-forwards | 10,000,000 | 10,000,000 |  |  |
Net change in valuation allowance |  | (100,000) |  |  |
Cash and cash equivalents | 86,433,000 | 86,433,000 | 79,895,000 | $ 84,550,000 | $ 73,439,000
Short-term investments | 16,129,000 | 16,129,000 | 43,188,000 |  |
Short-term liquidity amount | 102,600,000 | 102,600,000 | 123,100,000 |  |
Income tax benefit (expense) from stock options exercised adjustment to equity |  | 0 | 0 | (40,000) |
Unrecognized tax benefits | 2,366,000 | 2,366,000 | 2,226,000 | 2,537,000 | $ 3,334,000
Unrecognized tax benefits, effective tax rate | 2,200,000 | 2,200,000 | 1,700,000 | 1,800,000 |
Accrued interest and penalties | 800,000 | 800,000 | 800,000 | $ 900,000 |
Foreign Subsidiaries [Member] |  |  |  |  |
Income Tax Disclosure [Line Items] |  |  |  |  |
Short-term liquidity amount | $ 56,800,000 | $ 56,800,000 | $ 42,100,000 |  |
Short-term liquidity, in percentage | 55.40% | 55.40% | 34.20% |  |
Minimum [Member] |  |  |  |  |
Income Tax Disclosure [Line Items] |  |  |  |  |
Operating loss carry forwards expiration year |  | 2018 |  |  |
Maximum [Member] |  |  |  |  |
Income Tax Disclosure [Line Items] |  |  |  |  |
Operating loss carry forwards expiration year |  | 2030 |  |  |

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- Definition Amount of deferred tax assets related to foreign and domestic loss carry-forwards, unamortized research and development costs, and state credit carry-forwards. + References No definition available. + Details
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- Definition Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section 45 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=82887183&loc=d3e6676-107765 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3044-108585 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.1) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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- Definition Cash includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the customer may deposit additional funds at any time and effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid Investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months. Short-term investments, exclusive of cash equivalents, generally consist of marketable securities intended to be sold within one year (or the normal operating cycle if longer) and may include trading securities, available-for-sale securities, or held-to-maturity securities (if maturing within one year), as applicable. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.1) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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- Definition The tax effects of employee stock option transactions that are recognized differently for financial reporting and tax purposes, occurring during the period and charged or credited directly to shareholders' equity. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 740 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=79981250&loc=d3e23586-113945 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 740 -Section 45 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=79981250&loc=d3e23594-113945 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 20 -Section 45 -Paragraph 11 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=79507043&loc=d3e39076-109324 + Details
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- Definition The amount of estimated penalties and interest accrued as of the balance sheet date arising from income tax examinations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32718-109319 + Details
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- Definition Amount of tax expense (benefit), after reclassification adjustments, of appreciation (loss) in value of unsold available-for-sale securities. Excludes amounts related to other than temporary impairment (OTTI) loss. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 10A -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=84228862&loc=SL7669646-108580 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=84228862&loc=d3e640-108580 + Details
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