Stock Warrants - Schedule of Common Stock Warrant Activity of the Company (Detail) - Common Stock Warrant [Member] - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Class of Warrant or Right [Line Items]
Beginning Balance	2,381	2,777	2,842
Exercised (in shares)	(2,355)	(396)	(65)
Cancelled (in shares)	(26)
Ending Balance		2,381	2,777
Beginning Balance	$ 3.00	$ 3.05	$ 3.05
Exercised (per share)	3.00	3.38	2.82
Cancelled (per share)	$ 3.00
Ending Balance		$ 3.00	$ 3.05