Cash, Cash Equivalents and Short-Term Investments and Long-Term Investments (Detail) - USD ($) $ in Thousands	Apr. 01, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 44,860	$ 48,260
Unrealized Holdings Gains		1
Unrealized Holdings Losses	18	23
Fair Value	44,842	48,238
Municipal bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	600
Fair Value	600
Cash and Cash Equivalents
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	25,577	27,043
Fair Value	25,577	27,043
Short-term Investments
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	15,238	17,610
Unrealized Holdings Losses	11	8
Fair Value	15,227	17,602
Short-term Investments \| Corporate bonds and medium-term notes
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	8,231	8,586
Unrealized Holdings Losses	9	6
Fair Value	8,222	8,580
Short-term Investments \| Municipal bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		600
Fair Value		600
Short-term Investments \| U.S. treasury and agency securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	4,410	6,432
Unrealized Holdings Losses	2	1
Fair Value	4,408	6,431
Other Long-term Investments
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	4,045	3,607
Unrealized Holdings Gains		1
Unrealized Holdings Losses	7	15
Fair Value	4,038	3,593
Other Long-term Investments \| Corporate bonds and medium-term notes
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,948	2,510
Unrealized Holdings Losses	5	11
Fair Value	1,943	2,499
Other Long-term Investments \| Municipal bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	500	500
Unrealized Holdings Losses	2	4
Fair Value	498	496
Other Long-term Investments \| U.S. treasury and agency securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,597	597
Unrealized Holdings Gains		1
Fair Value	1,597	598
Cash
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	15,290	18,726
Fair Value	15,290	18,726
Money market funds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	8,414	8,317
Fair Value	8,414	8,317
Certificate of deposit \| Short-term Investments
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,000
Fair Value	1,000
Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,273
Fair Value	1,273
Commercial paper \| Short-term Investments
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,597	1,992
Unrealized Holdings Losses		1
Fair Value	$ 1,597	$ 1,991

This item represents the cost of debt securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27161-111563

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.2)
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