Income Taxes - Components of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Capitalized research expenditures	$ 32	$ 58
Deferred revenue	21	57
Tax credits	31	33
Net operating loss carryforwards	338	35
Other accruals	20	31
Inventory items	20	27
Capitalized software costs	14	25
Sales return/rebate reserve	33	27
Share-based compensation expense	12	15
Accrued bonus	1	11
Unrealized gain and losses on securities and investments	8	4
Valuation allowance	(134)	(47)
Total deferred tax assets	396	276
Deferred:
Depreciation and amortization	275	165
Undistributed earnings	2	1
Total deferred tax liabilities	277	166
Net deferred tax assets	$ 119	$ 110