Convertible Preferred Stock, Common Stock and Stockholders' Equity (Deficit) - Summary of Non-Cash Share-Based Compensation Expense (Detail) (USD $)	12 Months Ended			83 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 145,966	$ 12,505	$ 22,705	$ 235,677
Research and development [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	39,638	10,004	15,360	93,435
General and administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 106,328	$ 2,501	$ 7,345	$ 142,243