Fair Value Measurements - Summary of Unobservable Inputs in Fair Value Measurements (Detail) (USD $)	9 Months Ended			12 Months Ended
	Sep. 30, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 Employee Stock Option [Member]	Dec. 31, 2013 Employee Stock Option [Member] Maximum [Member]	Dec. 31, 2013 Accrued Warrant Liability [Member]	Dec. 31, 2013 Accrued Warrant Liability [Member] Maximum [Member]	Dec. 31, 2013 Accrued Warrant Liability [Member] Minimum [Member]	Dec. 31, 2013 Fair Value [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value		$ 1,550,761		$ 309,450		$ 1,241,311
Valuation Technique				Black-scholes pricing model		Black-scholes pricing model
Range	2 years 6 months				5 years		1 year 10 months 28 days	7 months 2 days
Unobservable Input				Expected term		Expected term
Quantity of options		5,564,833	5,016,916	5,564,833					696,000