Stock Options Outstanding Under Equity Incentive Plans (Detail) (USD $)	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding Options	433,000	546,001	652,001
Weighted Average Exercise Price	$ 3.60	$ 4.54	$ 5.01
Weighted Average Remaining Contractual Life (Years)	2 years 4 months 24 days	2 years 9 months 18 days
Options Exercisable	425,000	476,801
Weighted Average Exercise Price	$ 3.64	$ 5.01
Previously Approved Plans \| $0.63 - $4.50
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of exercise prices, lower limit	$ 0.63
Range of exercise prices, upper limit	$ 4.50
Outstanding Options	236,000
Weighted Average Exercise Price	$ 1.66
Weighted Average Remaining Contractual Life (Years)	2 years 10 months 24 days
Options Exercisable	228,000
Weighted Average Exercise Price	$ 1.65
Previously Approved Plans \| $4.75 - $9.80
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of exercise prices, lower limit	$ 4.75
Range of exercise prices, upper limit	$ 9.80
Outstanding Options	197,000
Weighted Average Exercise Price	$ 5.94
Weighted Average Remaining Contractual Life (Years)	1 year 10 months 24 days
Options Exercisable	197,000
Weighted Average Exercise Price	$ 5.94
Previously Approved Plans \| $0.63 - $9.80
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of exercise prices, lower limit	$ 0.63
Range of exercise prices, upper limit	$ 9.80
Outstanding Options	433,000
Weighted Average Exercise Price	$ 3.60
Weighted Average Remaining Contractual Life (Years)	2 years 4 months 24 days
Options Exercisable	425,000
Weighted Average Exercise Price	$ 3.64

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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- Definition

The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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- Definition

The number of shares reserved for issuance under stock option agreements awarded under the plan that validly exist and are outstanding as of the balance sheet date, including vested options.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph b(1)(b)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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- Definition

Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

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- Definition

Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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- Definition

The floor of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph 64

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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The ceiling of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

+ References

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