Nature of Business, Financial Condition and Basis of Presentation - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended		109 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Dec. 31, 2013	Dec. 31, 2012
Nature Of Business [Line Items]
Net loss from operation	$ (17,156)	$ (15,222)	$ (29,128)	$ (33,592)	$ (291,866)
Deficit accumulated during development stage	(291,281)		(291,281)		(291,281)	(262,153)
Cash and cash equivalents	$ 5,908	$ 40,588	$ 5,908	$ 40,588	$ 5,908	$ 24,625	$ 66,744