Income Taxes - Schedule of Effective Income Tax Rate Reflected in Provision for Income Taxes and U.S. Federal Statutory Rate (Detail)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Federal income tax statutory rate	35.00%	35.00%	35.00%
Foreign income tax rate differential	2.40%	(11.70%)	(7.30%)
Foreign development tax incentive	1.80%	(0.90%)	(1.30%)
Manufacturing benefit	(0.00%)	(1.10%)	(1.40%)
Foreign intellectual property tax benefit	16.10%	(1.00%)	(0.80%)
TCJA Transition Tax	(49.70%)	0.00%	0.00%
Deferred tax rate change	(20.70%)	0.00%	0.00%
Change in valuation allowance	(35.60%)	(0.00%)	(0.00%)
Other	(2.60%)	(0.80%)	(1.10%)
Effective income tax rate	(53.30%)	19.50%	23.10%