Condensed Consolidated Statements of Operations (unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Revenue:
Product revenue	$ 31,544	$ 28,072
Service revenue	10,774	10,833
Total revenue	42,318	38,905
Cost of sales	29,067	25,878
Gross profit	13,251	13,027
Operating expenses:
Product development and engineering	5,578	4,648
Selling, general and administrative	11,522	12,392
Total operating expenses	17,100	17,040
Operating loss	(3,849)	(4,013)
Interest expense	(150)	(132)
Other income, net	33	17
Loss before income taxes	(3,966)	(4,128)
Provision for income taxes	251	306
Net income (loss)	$ (4,217)	$ (4,434)
Net loss per share — basic (in usd per share)	$ (0.58)	$ (0.59)
Net loss per share — diluted (in usd per share)	$ (0.58)	$ (0.59)
Weighted average number of shares:
Basic (in shares)	7,283	7,568
Diluted (in shares)	7,283	7,568