Balance Sheet Components - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Inventory [Line Items]
Inventories, noncurrent portion	$ 56,096	$ 9,645
Long-term prepaid manufacturing	4,700	10,900
Charge for reserve on excess and obsolescence of inventories	4,152	2,246	$ 0
Cost of Sales
Inventory [Line Items]
Charge for reserve on excess and obsolescence of inventories	$ 17,800	$ 12,600

Amount of loss from reductions in inventory due to subsequent measurement adjustments, including, but not limited to, physical deterioration, obsolescence, or changes in price levels.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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