Summary of Significant Accounting Policies - Reconciliation of Basic and Diluted Net Income per Share (Detail) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Basic and diluted net loss per share:
Net loss	$ (1,359,941)	$ 575,677	$ (7,166,596)	$ 651,917
Weighted average common shares outstanding	24,262,417		24,485,429
Basic and diluted net loss per share	$ (0.06)		$ (0.29)
Basic:
Net income	(1,359,941)	575,677	(7,166,596)	651,917
Weighted average common shares outstanding, basic	24,262,417	24,677,893	24,485,429	24,625,851
Net income, basic	$ (0.06)	$ 0.02	$ (0.29)	$ 0.03
Diluted:
Net income	$ (1,359,941)	$ 575,677	$ (7,166,596)	$ 651,917
Weighted average common shares outstanding		24,677,893		24,625,851
Add: Options to purchase common shares		689,334		735,099
Weighted average common shares outstanding, diluted	24,262,417	25,367,227	24,485,429	25,360,950
Net income, diluted	$ (0.06)	$ 0.02	$ (0.29)	$ 0.03