Summary of Warrants and Related Information (Detail) - Warrant - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Warrants
Beginning balance	20,000	190,000	190,000
Exercised	0	(170,000)	0
Ending balance	20,000	20,000	190,000
Exercisable at December 31, 2015	20,000
Weighted Average Exercise Price
Beginning balance	$ 6.64	$ 19.80	$ 19.80
Exercised		21.35
Ending balance	6.64	$ 6.64	$ 19.80
Exercisable at December 31, 2015	$ 6.64