Consolidated Statements of Operations and Comprehensive Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Net sales	$ 420,068	$ 343,798	$ 268,245
Cost of sales	161,485	136,710	97,709
Gross margin	258,583	207,088	170,536
Sales, general and administrative	156,886	138,692	108,076
Research and development	76,856	55,373	30,609
Total operating expenses	233,742	194,065	138,685
Income from operations	24,841	13,023	31,851
Interest and other income (expense), net	3,263	2,738	(354)
Income before provision for income taxes	28,104	15,761	31,497
Provision (benefit) for income taxes	(1,101)	10,554	14,200
Net income	$ 29,205	$ 5,207	$ 17,297
Net income per share:
Basic (in dollars per share)	$ 0.52	$ 0.10	$ 0.33
Diluted (in dollars per share)	$ 0.50	$ 0.10	$ 0.32
Weighted average shares outstanding:
Basic (in shares)	56,392	52,726	52,667
Diluted (in shares)	57,922	53,898	53,536
Net income	$ 29,205	$ 5,207	$ 17,297
Foreign currency translation adjustments	(46)	(2,370)	820
Comprehensive income	29,159	2,837	18,117
Product
Net sales	327,635	285,859	238,573
Cost of sales	139,337	117,997	91,536
Service
Net sales	92,433	57,939	29,672
Cost of sales	$ 22,148	$ 18,713	$ 6,173