Consolidated Statements of Operations and Comprehensive Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
Net sales from products	$ 285,859	$ 238,573	$ 185,230
Net sales from services	57,939	29,672	12,662
Net sales	343,798	268,245	197,892
Cost of product sales	117,997	91,536	65,022
Cost of service sales	18,713	6,173	4,223
Cost of sales	136,710	97,709	69,245
Gross margin	207,088	170,536	128,647
Sales, general and administrative	138,692	108,076	69,698
Research and development	55,373	30,609	23,614
Total operating expenses	194,065	138,685	93,312
Income from operations	13,023	31,851	35,335
Interest and other income (expense), net	2,738	(354)	26
Income before provision for income taxes	15,761	31,497	35,361
Provision for income taxes	10,554	14,200	15,428
Net income	$ 5,207	$ 17,297	$ 19,933
Net income per common and common equivalent shares:
Basic (in dollars per share)	$ 0.10	$ 0.33	$ 0.37
Diluted (in dollars per share)	$ 0.10	$ 0.32	$ 0.36
Weighted average number of common and common equivalent shares outstanding:
Basic (in shares)	52,726	52,667	53,548
Diluted (in shares)	53,898	53,536	54,638
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Net income	$ 5,207	$ 17,297	$ 19,933
Foreign currency translation adjustments	(2,370)	820	19
Comprehensive income	$ 2,837	$ 18,117	$ 19,952