Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	1 Months Ended	3 Months Ended	12 Months Ended	64 Months Ended	1 Months Ended				3 Months Ended
	Mar. 31, 2014	Mar. 31, 2014 Segment	Dec. 31, 2013	Mar. 31, 2014	Feb. 28, 2014 Series E convertible preferred stock [Member]	Feb. 28, 2014 Series D convertible preferred stock [Member]	Mar. 31, 2014 Remeasurement [Member]	Mar. 31, 2014 IPO [Member]	Mar. 31, 2014 Minimum [Member]	Mar. 31, 2014 Maximum [Member]
Significant Accounting Policies [Line Items]
Number of operating segment		1
Reverse stock split		1-for-11.5
Cash and cash equivalents maturity period		Three months or less
Property and equipment estimated useful lives									3 years	5 years
Impairments of long-lived assets		$ 0	$ 0	$ 0
Inception date		Dec. 10, 2008
Warrants exercised, shares	158,179	158,179		158,179
Remeasurement of outstanding warrants	173,910
Warrants remeasured using intrinsic value of warrant computed as difference between IPO price and exercise price	5.17	5.17		5.17				21.00
Expense related to change in fair value							2,300,000
Reclassified to additional paid in capital							2,800,000
Remeasurement of preferred stock						9,600,000
Convertible preferred stock shares automatically converted into common stock	15,876,104	15,876,104		15,876,104	48,758,857
Convertible preferred stock, Purchase price					$ 1.128
Purchase price of convertible preferred stock					55,000,000
Deemed dividend		$ 25,559,000		$ 25,559,000	$ 25,600,000
Percentage for the amount of benefit realized upon ultimate settlement										50.00%