Discontinued Operations - Loss from discontinued operations attributable to DSL service assurance software product line (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss from discontinued operations		$ (1,943)		$ (2,216)
DSL service assurance software product line
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenue		156		1,217
Expenses		3,355		4,866
Loss before income taxes		(3,199)		(3,649)
Income tax benefit		1,256		1,433
Loss from discontinued operations		$ (1,943)		$ (2,216)