Acquisitions (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Jul. 14, 2016	Dec. 31, 2015	Dec. 31, 2014	Jul. 28, 2014
Business Acquisition [Line Items]
Accounts receivable					$ 468
Prepaid expenses and other current assets					288
Property and equipment, net					181
Other assets					21
Total identifiable assets acquired					6,439
Accounts payable and accrued expenses					583
Accrued salaries, wages and related benefits					315
Deferred revenues					382
Income and other taxes					310
Deferred tax liability					751
Capital lease obligation					38
Total liabilities assumed					2,379
Net identifiable assets acquired					4,060
Goodwill	$ 2,734		$ 1,476	$ 1,635	1,034
Net assets acquired					5,094
MediaMiser [Member]
Business Acquisition [Line Items]
Accounts receivable		$ 771
Total identifiable assets acquired		5,685
Accrued salaries, wages and related benefits		63
Deferred revenues		2,560
Income and other taxes		97
Total liabilities assumed		2,720
Net identifiable assets acquired		2,965
Goodwill		1,263
Net assets acquired		4,228
MediaMiser [Member] | Developed Technology Rights [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill		994			2,629
MediaMiser [Member] | Customer Relationships [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill					2,555
MediaMiser [Member] | Trademarks and Trade Names [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill		310			$ 297
MediaMiser [Member] | Database Rights [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill		$ 3,610