Income Taxes - Components of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Capitalized research expenditures	$ 18	$ 37
Deferred revenue	38	24
Tax credits	36	29
Net operating loss carryforwards	406	410
Other accruals	31	21
Inventory items	17	18
Capitalized software costs	0	2
Sales return/rebate reserve	46	48
Share-based compensation expense	9	12
Accrued bonus	1	7
Unrealized gains and losses on securities and investments	19	4
Valuation allowance	(413)	(421)
Total deferred tax assets	208	191
Deferred tax liabilities:
Depreciation and amortization	67	62
Undistributed earnings	2	2
Total deferred tax liabilities	69	64
Net deferred tax assets	$ 139	$ 127