Derivatives Instruments Designated as Cash Flow Hedges - (Detail) - Cash Flow Hedging [Member] - Foreign Exchange Contract [Member] - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in OCI	$ 151	$ (78)
Cost of revenue [Member]
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Reclassified from AOCI into Income	7	189
Selling, General and Administrative Expenses [Member]
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Reclassified from AOCI into Income	5	144
Research and development [Member]
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Reclassified from AOCI into Income	$ 7	$ 222

Amount before tax of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=114867106&loc=d3e637-108580

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=109978405&loc=d3e80720-113993

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 10A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=114867106&loc=SL7669646-108580

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration