Liquidity and Significant Uncertainties And Going Concern - Additional Information (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2014
Offsetting [Abstract]
Cash and cash equivalents	$ 15,529	$ 2,789	$ 7,549	$ 20,944
Accumulated deficit	(414,393)	$ (377,872)
Cash and cash equivalents minimum covenant requirement	$ 5,000
Debt covenant compliance	The Company’s cash balance will not be sufficient to satisfy the Company’s operations for the next 12 months from September 30, 2016 or maintain its liquidity covenant, which raises substantial doubt about the Company’s ability to continue as a going concern. The Company estimates that the cash balance will be sufficient to satisfy the Company’s operations into mid-first quarter of 2017.