Shareholders Equity - Additional Information (Detail) (USD $)	1 Months Ended		9 Months Ended	1 Months Ended	3 Months Ended	9 Months Ended
	Jul. 31, 2012	Mar. 28, 2012	Sep. 30, 2012	Jul. 31, 2012 Public Offering	Sep. 30, 2012 Public Offering	Sep. 30, 2012 Public Offering
Class of Stock [Line Items]
Public offering, number of shares of common stock sold				3,365,854	3,365,854	3,365,854
Public offering, common stock price per share				$ 10.25
Underwriting discounts and other offering expenses	$ 2,200,000
Public offering, net proceeds			32,306,000	32,300,000
Warrants, expiration date extension period		1 year
Warrants, shares of our common stock that can be purchased by warrant		197,478
Warrants, exercise price		12.25
Warrants, expiration date			Mar. 29, 2013
Change in fair value of warrants			$ (511,000)