Segment Information - Significant Segment Financial Data (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Segment Reporting Information [Line Items]
Net revenues	$ 64,017us-gaap_SalesRevenueNet	$ 53,233us-gaap_SalesRevenueNet
Income (loss) from operations	3,610us-gaap_OperatingIncomeLoss	(5,439)us-gaap_OperatingIncomeLoss
Total assets	161,273us-gaap_Assets	163,088us-gaap_Assets	155,542us-gaap_Assets
Depreciation and amortization	2,403	2,443
Operating Segments [Member] \| BBU [Member]
Segment Reporting Information [Line Items]
Net revenues	44,878	43,689
Income (loss) from operations	5,379	2,312
Total assets	155,737	138,770
Depreciation and amortization	1,153	1,193
Operating Segments [Member] \| VI Chip [Member]
Segment Reporting Information [Line Items]
Net revenues	14,180	9,341
Income (loss) from operations	(3,488)	(6,847)
Total assets	17,125	20,011
Depreciation and amortization	799	791
Operating Segments [Member] \| Picor [Member]
Segment Reporting Information [Line Items]
Net revenues	7,109	2,950
Income (loss) from operations	2,017	(742)
Total assets	7,489	4,514
Depreciation and amortization	97	101
Operating Segments [Member] \| Corporate [Member]
Segment Reporting Information [Line Items]
Income (loss) from operations	(298)	(162)
Total assets	79,483	75,130
Depreciation and amortization	354	358
Eliminations [Member]
Segment Reporting Information [Line Items]
Net revenues	(2,150)	(2,747)
Total assets	$ (98,561)	$ (75,337)

Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.18)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

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-Section S99

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 12

-Article 7

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

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- Definition

The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

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- Definition

The net result for the period of deducting operating expenses from operating revenues.

+ References

No definition available.

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- Definition

Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef

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-Name Regulation S-X (SX)

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