Financing Arrangements - Summary of Interest Expense Recognized (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Debt Disclosure [Abstract]
Contractual interest coupon	$ 781	$ 182	$ 2,344	$ 182
Amortization of debt issuance costs	295	68	883	68
Amortization of debt discount	1,795	406	5,324	406
Total interest expense	$ 2,871	$ 656	$ 8,551	$ 656