Patents Cost and Accumulated Amortization (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Patents [Line Items]
Patent cost, disposals	$ 3,000actg_PatentCostDisposals	$ 3,500actg_PatentCostDisposals	$ 5,500actg_PatentCostDisposals
Accumulated amortization, disposals	298actg_AccumulatedAmortizationDisposals	1,753actg_AccumulatedAmortizationDisposals	2,466actg_AccumulatedAmortizationDisposals
Proceeds from Sale of Intangible Assets	$ 3,500	$ 1,000	$ 2,792

The cash inflow from disposal of asset without physical form usually arising from contractual or other legal rights, excluding goodwill.

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 12

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3179-108585

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Data Type:	xbrli:monetaryItemType
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Period Type:	duration