Quarterly Financial Results (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2016		Sep. 30, 2016		Jun. 30, 2016		Mar. 31, 2016		Dec. 31, 2015		Sep. 30, 2015		Jun. 30, 2015		Mar. 31, 2015		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Product sales	$ 18,611		$ 19,020		$ 20,062		$ 15,382		$ 27,259		$ 15,622		$ 17,946		$ 15,386		$ 73,075	$ 76,213	$ 81,143
Service sales	25,319		26,826		25,904		24,998		26,760		28,833		26,909		25,919		103,047	108,421	91,448
Cost of Goods Sold	11,674		11,001		12,989		10,670		14,627		10,275		12,017		10,485		46,334	47,404	48,843
Cost of Services	13,140		13,576		13,259		12,991		13,409		14,454		13,693		13,260		52,966	54,816	50,301
Operating Expenses	19,384		18,256		20,411		20,093		20,815		19,520		19,403		19,468
Operating Income (Loss)	(268)		3,013		(693)		(3,374)										(1,322)	3,208	1,922
(Loss) income from operations									5,168		206		(258)		(1,908)
Net (loss) income	$ (6,783)		$ 2,863		$ (806)		$ (2,791)		$ 4,101		$ (463)		$ 37		$ (1,422)		$ (7,517)	$ 2,253	$ 41
Net (loss) income per share:
Basic (in dollars per share)	$ (0.43)	[1]	$ 0.18	[1]	$ 0	[1]	$ (0.18)	[1]	$ 0.26	[1]	$ (0.03)	[1]	$ 0	[1]	$ (0.09)	[1]	$ (0.47)	$ 0.14	$ 0.00
Diluted (in dollars per share)	$ (0.43)	[1]	$ 0.18	[1]	$ 0	[1]	$ (0.18)	[1]	$ 0.26	[1]	$ (0.03)	[1]	$ 0	[1]	$ (0.09)	[1]	$ (0.47)	$ 0.14	$ 0.00

[1] Net (loss) income per share is computed independently for each of the quarters. Therefore, the net (loss) income per share for the four quarters may not equal the annual net (loss) income per share data.