Note Payable - Additional Information (Detail) (USD $)	12 Months Ended		0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Jul. 05, 2013
Debt [Line Items]
Unregistered shares of common stock	357,356
Warrant exercise price	$ 4.20	$ 5.00
Days of volume-weighted average share price	20-day volume-weighted average share price of the Common Stock prior to the closing of the Loan
Warrant exercisable term	5 years
Amortization Period of Discount	3 years
Term of loan	36 months
Interest rate		8.45%
LIBOR floor rate		0.50%
Interest rate at period end	8.95%	8.95%
Final payment fee rate	3.50%
Closing fee	0.50%
Exit fee percentage recorded as deferred loan costs	3.50%
Loan amount prepaid in each year thereafter the first year	3.00%
Mid Cap [Member]
Debt [Line Items]
Secured loan facility			$ 20,000,000
Net proceeds in aggregate amount			19,800,000
Unregistered shares of common stock	357,356
Warrant exercise price	$ 4.20
Secured loan facility due to Midcap	12,173,000
Unamortized net discount	$ 494,000