Unaudited Condensed Consolidated Statements of Operations and Comprehensive Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
Net sales from products	$ 80,974	$ 67,491
Net sales from services	20,241	11,751
Net sales	101,215	79,242
Cost of product sales	32,434	27,072
Cost of service sales	4,320	3,500
Cost of sales	36,754	30,572
Gross margin	64,461	48,670
Operating expenses:
Sales, general and administrative	35,759	30,857
Research and development	15,119	12,463
Total operating expenses	50,878	43,320
Income from operations	13,583	5,350
Interest and other income, net	1,263	206
Income before provision for income taxes	14,846	5,556
Provision for income taxes	1,920	976
Net income	$ 12,926	$ 4,580
Net income per common and common equivalent shares:
Basic (in dollars per share)	$ 0.24	$ 0.09
Diluted (in dollars per share)	$ 0.24	$ 0.09
Weighted average number of common and common equivalent shares outstanding:
Basic (in shares)	53,119	52,418
Diluted (in shares)	54,532	53,677
UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Net income	$ 12,926	$ 4,580
Foreign currency translation adjustments	(707)	165
Comprehensive income	$ 12,219	$ 4,745