Selected Quarterly Financial Data (Unaudited) - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]
Litigation settlement, amount		$ 3,400							$ 3,200
Net income (loss)	$ 287	$ (3,018)	$ 315	$ 486	$ 21,968	$ 2,120	$ 3,469	$ 511	$ (1,930)	$ 28,068	$ 9,180
Benefit for income taxes from change in deferred tax valuation allowance					$ 20,200