Equity - Additional Information (Detail) (USD $)	0 Months Ended	3 Months Ended		9 Months Ended			0 Months Ended			9 Months Ended
	Jan. 10, 2013	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Apr. 15, 2013	Sep. 03, 2013 Chief Financial Officer	Apr. 03, 2013 Chief Financial Officer	Apr. 07, 2013 Chief Financial Officer	Sep. 30, 2013 Chief Financial Officer
Equity [Line Items]
Equity issuance, per share amount	$ 1.80
Proceeds from issuance of common stock	$ 12,600,000			$ 12,522,000	$ 0
Offering costs				78,000
Class of warrant or right, number of securities called by warrants or rights						2,500,000
Share based compensation arrangement byshare based payment award options grants in period gross							136,924	360,000	223,076
Share based compensation		375,002	379,450	1,133,790	1,047,355		169,786		305,614	475,400
Warrants issued, exercise price						1.80
Cash payment						$ 4,500,000
Stock Issued During Period, Shares, New Issues	7,000,000