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The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

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Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

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Amount, after adjustment, of cost-method investment. Adjustments include, but are not limited to, dividends received in excess of earnings after date of investment that are considered a return of investment and other than temporary impairments.

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This item represents an other than temporary decline in value that has been recognized against an investment accounted for under the cost method of accounting. The excess of the carrying amount over the fair value of the investment represents the amount of the write down which is or was reflected in earnings. The written down value is a new cost basis with the adjusted value of the investment becoming its new carrying value. Evidence of a loss in value might include, but would not necessarily be limited to, absence of an ability to recover the carrying amount of the investment or inability of the investee to sustain an earnings capacity which would justify the carrying amount of the investment.

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- Definition

For investments in debt and equity securities accounted for at cost, the excess of net sale proceeds over the carrying amount of investments disposed of during the period.

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

-Publisher SEC

-Name Regulation S-X (SX)

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-Subparagraph (SX 210.5-03.7(c))

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The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

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- Definition

Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

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Amount of accumulated impairment loss for an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of increase (decrease) from adjustments after acquisition date under purchase accounting of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit.

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Balance Sheet Components (Narrative) (Details) (USD $)	12 Months Ended			3 Months Ended
Balance Sheet Components (Narrative) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Sep. 29, 2013	Jul. 03, 2012	Apr. 02, 2013	Jun. 04, 2012
Balance Sheet Components [Line Items]
Goodwill, Impaired, Accumulated Impairment Loss	$ 74,200,000	$ 0
2019	6,028,000
2015	16,921,000
Cost method investment	1,322,000us-gaap_CostMethodInvestments	1,322,000us-gaap_CostMethodInvestments
Cost-method Investments, Other than Temporary Impairment	0	0	0
Depreciation	17,600,000us-gaap_Depreciation	17,300,000us-gaap_Depreciation	11,900,000us-gaap_Depreciation
Indefinite-lived intangible assets		100,000
Amortization expense	17,900,000us-gaap_AmortizationOfIntangibleAssets	15,500,000us-gaap_AmortizationOfIntangibleAssets	4,900,000us-gaap_AmortizationOfIntangibleAssets
Goodwill, Acquired During Period		55,035,000us-gaap_GoodwillAcquiredDuringPeriod
Goodwill impairment charges	74,196,000us-gaap_GoodwillImpairmentLoss	0us-gaap_GoodwillImpairmentLoss	0us-gaap_GoodwillImpairmentLoss
Intangibles Impairment charges	0us-gaap_AssetImpairmentCharges	2,000,000us-gaap_AssetImpairmentCharges	0us-gaap_AssetImpairmentCharges
Goodwill	81,721,000us-gaap_Goodwill	155,916,000us-gaap_Goodwill	100,881,000us-gaap_Goodwill
Cost-method Investments, Realized Gains	0	0	3,100,000
Minimum [Member]
Balance Sheet Components [Line Items]
Available-for-sale Securities, Maturity Period ( in months)	3 months
Maximum [Member]
Balance Sheet Components [Line Items]
Available-for-sale Securities, Maturity Period ( in months)	12 months
Retail [Member]
Balance Sheet Components [Line Items]
Goodwill, Acquired During Period		0
Goodwill impairment charges	0	0	0
Goodwill	45,442,000	45,442,000	45,442,000
Commercial [Member]
Balance Sheet Components [Line Items]
Goodwill, Acquired During Period		1,195,000
Goodwill impairment charges	0	0	0
Goodwill	36,279,000	36,279,000	35,084,000
Service Provider [Member]
Balance Sheet Components [Line Items]
Goodwill, Acquired During Period		53,841,000
Goodwill impairment charges	74,196,000	0	0
Goodwill	0	74,196,000	20,355,000
Avaak Inc. [Member]
Balance Sheet Components [Line Items]
Goodwill					11,895,000
Sierra Wireless AirCard Business [Member]
Balance Sheet Components [Line Items]
Goodwill, Purchase Accounting Adjustments				500,000
Intangibles Impairment charges		2,000,000		2,000,000
Goodwill						53,841,000
Firetide, Inc. [Member]
Balance Sheet Components [Line Items]
Goodwill							$ 3,041,000