Stock Based Compensation - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended					1 Months Ended	6 Months Ended				1 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011	Jun. 30, 2012 Restricted Stock	Dec. 31, 2011 Restricted Stock	Aug. 31, 2008 2008 Plan	Jun. 30, 2012 2008 Plan	Jun. 30, 2011 2008 Plan	Jun. 30, 2012 2008 Plan Restricted Stock Minimum	Jun. 30, 2012 2008 Plan Restricted Stock Maximum	Aug. 31, 2008 Previously Approved Plans	Jun. 30, 2012 Previously Approved Plans Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares initially authorized for issuance under equity incentive plan								300,000
Additional shares authorized for issuance under equity incentive plan								41,500
Shares ceased to be issuable													41,500
Outstanding options to purchase shares of common stock	436,001		436,001		546,001
Unvested restricted shares outstanding						319,001
Outstanding shares remained available for future grants									17,666
Restricted shares outstanding						319,001	232,501							0
Share-base compensation expense	$ 120,000	$ 102,000	$ 219,000	$ 225,000
Vesting period											3 years	4 years
Unrecognized compensation cost related to the nonvested service-conditioned restricted shares									$ 821,210	$ 887,158
Unrecognized compensation costs are expected to be recognized over a weighted average period (years)									2 years 1 month 6 days	2 years 4 months 24 days