3. Business acquisitions (Details) - Goodwill Rollforward (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2013
Goodwill Rollforward [Abstract]
Balance at December 31, 2011	$ 2,518	$ 2,621
Inventory measurement adjustment in connection with Printrex acquisition	103
Balance at December 31, 2012	$ 2,621	$ 2,621

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.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (g)

-URI http://asc.fasb.org/extlink&oid=14024403&loc=d3e13816-109267

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 25

-Paragraph 16

-URI http://asc.fasb.org/extlink&oid=21917927&loc=d3e961-128460

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration