Debt - Interest Expense Associated with Convertible Notes (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Debt Disclosure [Abstract]
Contractual coupon rate of interest	$ 584	$ 586	$ 1,753	$ 1,753
Accretion of Convertible Notes discount and amortization of deferred financing costs	1,097	840	3,237	2,740
Interest expense for the convertible notes	$ 1,681	$ 1,426	$ 4,990	$ 4,493