Share-Based Payments and Employee Benefits - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended		12 Months Ended	6 Months Ended		3 Months Ended		6 Months Ended		12 Months Ended	6 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended	6 Months Ended	1 Months Ended				6 Months Ended	1 Months Ended	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012	Jun. 30, 2013 Maximum	Jun. 30, 2013 Minimum	Jun. 30, 2013 Restricted Stock	Jun. 30, 2012 Restricted Stock	Jun. 30, 2013 Restricted Stock	Jun. 30, 2012 Restricted Stock	Dec. 31, 2012 Restricted Stock	Jun. 30, 2013 Restricted Stock Maximum	Jun. 30, 2013 Stock Options	Jun. 30, 2012 Stock Options	Jun. 30, 2013 Stock Options	Jun. 30, 2012 Stock Options	Dec. 31, 2012 Stock Options	Jun. 30, 2013 Stock Options Maximum	Jun. 05, 2013 Board Restricted Stock	May 03, 2013 Board Restricted Stock	Jan. 31, 2013 Board Restricted Stock	Aug. 06, 2012 Board Restricted Stock	Jun. 30, 2013 Board Restricted Stock January 1, 2014	Jun. 05, 2013 CEO Stock Options	Jun. 30, 2013 CEO Stock Options	Jun. 30, 2013 CEO Stock Options First options	Jun. 30, 2013 CEO Stock Options Remaining options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate grant date fair value per nonexecutive director	$ 75,000		$ 75,000
Shares authorized under the incentive plan	25,000,000		25,000,000
Shares available for grant under the incentive plan	5,700,000		5,700,000		8,800,000
Restricted common stock awards, vesting period													5 years						4 years
Shares of restricted stock that vested early																							1,111,112
Restricted shares granted										1,231,708		3,210,244								250,000	250,000	182,927
Grant date value of restricted stock award																					138,750			167,500
Vesting date of the shares granted																								Jan. 01, 2014
Compensation expenses for share-based awards			946,000	747,000				400,000	200,000	600,000	400,000			200,000	200,000	400,000	400,000
Unrecognized share-based compensation expense								700,000		700,000		700,000		1,200,000		1,200,000
Unrecognized share-based compensation expense weighted average contractual term										1 year		1 year 7 months 6 days				1 year 4 months 24 days
Common stock options term						10 years	8 years
Grant date fair value per share	$ 0.27		$ 0.27		$ 0.17
Options granted			2,050,000		1,846,000																				2,000,000		500,000	1,500,000
Percentage of options that vest every six months																										25
Exercise price																											$ 0.85	$ 1.00
Grant date fair value of options granted																										549,714
Options outstanding weighted average remaining contractual life (in years)																8 years		8 years 7 months 6 days
Options exercisable weighted average remaining contractual life (in years)																8 years
Percentage of company match of employee contributions			100.00%
Percentage of employee cash compensation match			4.00%
Matching contribution	$ 47,000	$ 15,000	$ 100,000	$ 15,000