Information About Employee Stock Warrants and Options Outstanding (Detail) (USD $)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Warrants and Options Outstanding	998,432	1,030,807	682,141
Warrants and Options Outstanding Remaining Contractual Life	7 years 6 months 29 days	8 years 2 months 8 days	8 years 6 months 7 days
Warrants and Options Outstanding Weighted Average Exercise Price	$ 6.34	$ 6.39	$ 6.47
Number of Warrants and Options Exercisable	673,473	410,593	262,952
Number of Warrants and Options Weighted Average Execise Price	$ 6.41	$ 6.80	$ 7.31
Exercise Price 4.56
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Warrants and Options Outstanding	63,561	84,675	84,675
Warrants and Options Outstanding Weighted Average Exercise Price	$ 4.56	$ 4.56	$ 4.56
Number of Warrants and Options Exercisable	61,102	48,183	0
Number of Warrants and Options Weighted Average Execise Price	$ 4.56	$ 4.56	$ 4.56
Exercise Price 4.58
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Warrants and Options Outstanding	7,500	10,167	10,167
Warrants and Options Outstanding Weighted Average Exercise Price	$ 4.58	$ 4.58	$ 4.58
Number of Warrants and Options Exercisable	7,500	10,167	10,167
Number of Warrants and Options Weighted Average Execise Price	$ 4.58	$ 4.58	$ 4.58
Exercise Price 5.70
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Warrants and Options Outstanding	37,416	38,416	39,750
Warrants and Options Outstanding Weighted Average Exercise Price	$ 5.70	$ 5.70	$ 5.70
Number of Warrants and Options Exercisable	37,416	38,416	39,750
Number of Warrants and Options Weighted Average Execise Price	$ 5.70	$ 5.70	$ 5.70
Exercise Price 6.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Warrants and Options Outstanding	330,000	330,000	330,000
Warrants and Options Outstanding Weighted Average Exercise Price	$ 6.00	$ 6.00	$ 6.00
Number of Warrants and Options Exercisable	192,500	110,000	27,500
Number of Warrants and Options Weighted Average Execise Price	$ 6.00	$ 6.00	$ 6.00
Exercise Price 6.25
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Warrants and Options Outstanding	350,000	350,000
Warrants and Options Outstanding Weighted Average Exercise Price	$ 6.25	$ 6.25
Number of Warrants and Options Exercisable	175,000	0
Number of Warrants and Options Weighted Average Execise Price	$ 6.25	$ 6.25
Exercise Price 6.92
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Warrants and Options Outstanding	69,138
Warrants and Options Outstanding Weighted Average Exercise Price	$ 6.92
Number of Warrants and Options Exercisable	69,138
Number of Warrants and Options Weighted Average Execise Price	$ 6.92
Exercise Price 7.50
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Warrants and Options Outstanding	71,196	124,573	124,573
Warrants and Options Outstanding Weighted Average Exercise Price	$ 7.50	$ 7.50	$ 7.50
Number of Warrants and Options Exercisable	71,196	124,573	124,573
Number of Warrants and Options Weighted Average Execise Price	$ 7.50	$ 7.50	$ 7.50
Exercise Price 8.15
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Warrants and Options Outstanding	15,000
Warrants and Options Outstanding Weighted Average Exercise Price	$ 8.15
Number of Warrants and Options Exercisable	5,000
Number of Warrants and Options Weighted Average Execise Price	$ 8.15
Exercise Price 9.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Warrants and Options Outstanding	54,621	92,976	92,976
Warrants and Options Outstanding Weighted Average Exercise Price	$ 9.00	$ 9.00	$ 9.00
Number of Warrants and Options Exercisable	54,621	79,254	60,962
Number of Warrants and Options Weighted Average Execise Price	$ 9.00	$ 9.00	$ 9.00

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Weighted average exercise price as of the balance sheet date for those equity-based payment arrangements exercisable and outstanding.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(iii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The number of shares reserved for issuance pertaining to the outstanding exercisable stock options as of the balance sheet date in the customized range of exercise prices for which the market and performance vesting condition has been satisfied.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(iii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The number of shares reserved for issuance pertaining to the outstanding stock options as of the balance sheet date for all option plans in the customized range of exercise prices.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(i)-(ii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The weighted average price as of the balance sheet date at which grantees could acquire the underlying shares with respect to all outstanding stock options which are in the customized range of exercise prices.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(i)-(ii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

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

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (e)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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