Options Outstanding (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]
Exercisable, Number of Shares Issuable	3,578,567
Not vested, Number of Shares Issuable	2,131,558
Balance, Ending	5,710,125	5,886,261	3,488,761
Exercisable, Weighted-Average Exercise Price	$ 1.04
Not vested, Weighted-Average Exercise Price	$ 1.22
Balance, Ending	$ 1.10	$ 1.11	$ 1.02
Exercisable, Weighted-Average Remaining Term (Years)	3 years
Not vested, Weighted-Average Remaining Term (Years)	3 years 3 months 18 days
Balance, Weighted-Average Remaining Term (Years)	3 years 2 months 12 days
Exercisable, Aggregate Intrinsic Value	$ 82,177
Not vested, Aggregate Intrinsic Value	200,034
Balance, Aggregate Intrinsic Value	$ 282,211