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.

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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.

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of options outstanding.

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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.

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

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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.

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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.

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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.

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Stock options and restricted stock outstanding and exercisable (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Outstanding,share	2,302,000	2,228,067	1,611,267
Weighted Avg. remaining contractual life,share outstanding	6 years 9 months 29 days
Weighted Avg. Exercise Price,share outstanding	$ 1.06	$ 1.14	$ 1.54
Exercisable, Share	1,376,950	1,099,817
Exercisable, Weighted Avg. Exercise Price	$ 1.49	$ 1.72
Aggregate intrinsic value	$ 5,075
Issuance One [Member]
Range of Exercise Price: Lower	$ 0.01
Range of Exercise Price:Upper	$ 1.00
Issuance Two [Member]
Range of Exercise Price: Lower	$ 1.01
Range of Exercise Price:Upper	$ 2.00
Issuance Three [Member]
Range of Exercise Price: Lower	$ 2.01
Range of Exercise Price:Upper	$ 3.00
Issuance Four [Member]
Range of Exercise Price: Lower	$ 3.01
Range of Exercise Price:Upper	$ 4.00
Issuance Five [Member]
Range of Exercise Price: Lower	$ 4.01
Range of Exercise Price:Upper	$ 5.00
Stock Option Or Restricted Stock Outstanding [Member]
Aggregate intrinsic value	5,075
Stock Option Or Restricted Stock Outstanding [Member] \| Issuance One [Member]
Outstanding,share	1,497,000
Weighted Avg. remaining contractual life,share outstanding	8 years 6 months 7 days
Weighted Avg. Exercise Price,share outstanding	$ 0.44
Stock Option Or Restricted Stock Outstanding [Member] \| Issuance Two [Member]
Outstanding,share	547,500
Weighted Avg. remaining contractual life,share outstanding	4 years 10 months 10 days
Weighted Avg. Exercise Price,share outstanding	$ 1.17
Stock Option Or Restricted Stock Outstanding [Member] \| Issuance Three [Member]
Outstanding,share	0
Weighted Avg. Exercise Price,share outstanding	$ 0
Stock Option Or Restricted Stock Outstanding [Member] \| Issuance Four [Member]
Outstanding,share	45,000
Weighted Avg. remaining contractual life,share outstanding	2 years 15 days
Weighted Avg. Exercise Price,share outstanding	$ 3.67
Stock Option Or Restricted Stock Outstanding [Member] \| Issuance Five [Member]
Outstanding,share	212,500
Weighted Avg. remaining contractual life,share outstanding	1 year 11 days
Weighted Avg. Exercise Price,share outstanding	$ 4.61
Stock Option Or Restricted Stock Exercisable [Member]
Aggregate intrinsic value	$ 0
Stock Option Or Restricted Stock Exercisable [Member] \| Issuance One [Member]
Exercisable, Share	593,050
Exercisable, Weighted Avg. Exercise Price	$ 0.49
Stock Option Or Restricted Stock Exercisable [Member] \| Issuance Two [Member]
Exercisable, Share	526,400
Exercisable, Weighted Avg. Exercise Price	$ 1.16
Stock Option Or Restricted Stock Exercisable [Member] \| Issuance Three [Member]
Exercisable, Share	0
Exercisable, Weighted Avg. Exercise Price	$ 0
Stock Option Or Restricted Stock Exercisable [Member] \| Issuance Four [Member]
Exercisable, Share	45,000
Exercisable, Weighted Avg. Exercise Price	$ 3.67
Stock Option Or Restricted Stock Exercisable [Member] \| Issuance Five [Member]
Exercisable, Share	212,500
Exercisable, Weighted Avg. Exercise Price	$ 4.61