Segment Reporting and Geographic Information (Statement of Operations Information by Business Segment) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Gross profit
Gross profit	$ 16,620	$ 14,974	$ 13,372	$ 13,027	$ 14,787	$ 14,372	$ 13,312	$ 12,681	$ 57,993		$ 55,152		$ 61,674
Depreciation expense
Depreciation expense									1,833		1,448		1,266
Operating income (loss)
Operating income (loss)	128	39	(535)	(4,013)	(2,838)	(2,120)	(1,244)	(3,645)	(4,381)		(9,847)		(3,717)
Provision (benefit) for income taxes	1,075	12	115	306	1,077	(869)	296	(1,517)	1,508		(1,013)		(1,191)
Operating Segments [Member]
Gross profit
Gross profit									57,986		55,157		62,082
Operating income (loss)
Operating income (loss)									2,921		5,610		10,575
Network Equipment segment [Member]
Gross profit
Gross profit									47,069		43,325		49,423
Depreciation expense
Depreciation expense									1,417		1,022		843
Operating income (loss)
Operating income (loss)									(1,699)		1,096		4,539
Provision (benefit) for income taxes									(38)		(2,468)		(3,289)
Network Integration segment [Member]
Gross profit
Gross profit									10,917		11,832		12,659
Depreciation expense
Depreciation expense									219		234		243
Operating income (loss)
Operating income (loss)									4,620		4,514		6,036
Provision (benefit) for income taxes									1,546		1,455		2,098
Corporate Unallocated and Intersegment Adjustments [Member]
Gross profit
Gross profit									7	[1]	(5)	[1]	(408)	[1]
Operating income (loss)
Operating income (loss)									(7,302)	[1]	(15,457)	[1]	(14,292)	[1]
Corporate [Member]
Depreciation expense
Depreciation expense									197		192		180
Operating income (loss)
Provision (benefit) for income taxes									$ 0		$ 0		$ 0

[1] Adjustments reflect the elimination of intersegment revenue and profit in inventory.