Subsequent Events - Additional Information (Detail) (USD $)	99 Months Ended				0 Months Ended		1 Months Ended		0 Months Ended	1 Months Ended			0 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Dec. 07, 2012	Feb. 28, 2011	Oct. 30, 2013 Subsequent Event [Member]	Oct. 08, 2013 Subsequent Event [Member]	Oct. 31, 2013 Subsequent Event [Member]	Oct. 24, 2013 Subsequent Event [Member]	Oct. 30, 2013 Subsequent Event [Member] Stock Offering Underwriter Over-Allotment Option [Member]	Oct. 31, 2013 Subsequent Event [Member] Stock Offering Underwriter Over-Allotment Option [Member]	Oct. 30, 2013 Subsequent Event [Member] Omnibus Incentive Plan [Member]	Oct. 30, 2013 Subsequent Event [Member] Employee Stock Purchase Plan [Member]	Oct. 30, 2013 Subsequent Event [Member] Conversion One [Member] Convertible Preferred Stock [Member]	Oct. 30, 2013 Subsequent Event [Member] Conversion Two [Member] Convertible Preferred Stock [Member]	Oct. 30, 2013 Subsequent Event [Member] Conversion Three [Member] Convertible Preferred Stock [Member]	Oct. 30, 2013 Subsequent Event [Member] Conversion Four [Member] Convertible Preferred Stock [Member]
Subsequent Event [Line Items]
Reverse split of common stock						1-for-5
Common stock, shares issued					6,720,000		6,720,000		1,008,000	1,008,000
Common stock, offering price per share					$ 10.00		$ 10.00
Net proceeds from initial public offering					$ 68,300,000		$ 68,300,000
Underwriting discounts and commissions					5,400,000		5,400,000
Expenses for initial public offering					3,600,000		3,600,000
Warrants exercised to purchase convertible preferred stock					931,240			1,486,830
Conversion of convertible securities to common stock													297,366	186,248	12,120,531
Debt conversion, shares issued					1,860,363
Debt conversion, conversion price per share					$ 10.00
Debt instrument, aggregate principal amount	$ 17,364,000				$ 18,000,000
Debt instrument, interest rate					8.00%
Debt instrument, maturity date					Dec. 31, 2013
Warrants to purchase convertible preferred stock																3,589,005
Warrants to purchase common stock																717,801
Increase in common stock, shares authorized as per amendment	22,000,000	20,000,000	20,000,000	15,734,582	150,000,000
Common stock, par value	$ 0.001	$ 0.001			$ 0.001
Decrease in preferred stock, shares authorized as per amendment					15,000,000
Preferred stock, par value					$ 0.001
Equity awards											3,229,068	645,814