Debt - Interest Expense Associated with Convertible Notes (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Debt Disclosure [Abstract]
Contractual coupon rate of interest	$ 584	$ 586	$ 1,169	$ 1,170
Accretion of Convertible Notes discount and amortization of deferred financing costs	994	917	1,962	1,898
Interest expense for the convertible notes	$ 1,578	$ 1,503	$ 3,131	$ 3,068