Condensed Consolidated Statements of Operations (Unaudited) (USD $) In Thousands, except Share data	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Sales and service revenue
Product sales	$ 39,044	$ 36,657	$ 76,398	$ 76,901
Service revenue	24,304	19,288	47,849	39,459
Net sales	63,348	55,945	124,247	116,360
Cost of sales and service revenue
Cost of product sales	27,857	27,030	54,506	56,546
Cost of service revenue	20,246	15,690	39,938	32,183
Cost of sales	48,103	42,720	94,444	88,729
Gross profit	15,245	13,225	29,803	27,631
Selling, general and administrative expenses	8,523	7,763	17,174	15,803
Income from operations	6,722	5,462	12,629	11,828
Other expense:
Interest expense, net	(118)	(167)	(255)	(394)
Other, net	(585)	(41)	(562)	(45)
Total other expense	(703)	(208)	(817)	(439)
Income before income taxes	6,019	5,254	11,812	11,389
Provision for income taxes	2,053	1,918	3,577	4,157
Net income	$ 3,966	$ 3,336	$ 8,235	$ 7,232
Amounts per common share:
Net income per common share (in dollars per share)	$ 0.34	$ 0.29	$ 0.71	$ 0.63
Net income per common share assuming dilution (in dollars per share)	$ 0.34	$ 0.29	$ 0.70	$ 0.62
Weighted average common shares outstanding ( in shares)	11,548,139	11,416,021	11,528,776	11,393,022
Weighted average dilutive common shares outstanding ( in shares)	11,747,230	11,640,826	11,721,361	11,603,850