Unaudited Condensed Consolidated Statements of Operations and Comprehensive Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Statement [Abstract]
Net sales from products	$ 73,985	$ 63,204	$ 208,351	$ 167,745
Net sales from services	16,277	8,678	40,796	18,423
Net sales	90,262	71,882	249,147	186,168
Cost of product sales	34,573	23,664	91,817	61,172
Cost of service sales	5,924	1,653	13,258	4,230
Cost of sales	40,497	25,317	105,075	65,402
Gross margin	49,765	46,565	144,072	120,766
Operating expenses:
Sales, general and administrative	36,398	28,121	99,079	77,333
Research and development	14,166	7,358	39,618	20,995
Total operating expenses	50,564	35,479	138,697	98,328
Income (loss) from operations	(799)	11,086	5,375	22,438
Interest and other income (expense), net	1,430	(455)	3,320	(460)
Income before provision for income taxes	631	10,631	8,695	21,978
Provision for income taxes	209	6,788	1,417	11,022
Net income	$ 422	$ 3,843	$ 7,278	$ 10,956
Net income per common and common equivalent shares:
Basic (in dollars per share)	$ 0.01	$ 0.07	$ 0.14	$ 0.21
Diluted (in dollars per share)	$ 0.01	$ 0.07	$ 0.14	$ 0.20
Weighted average number of common and common equivalent shares outstanding:
Basic (in shares)	52,831	52,206	52,663	52,791
Diluted (in shares)	53,843	53,141	53,762	53,656
UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Net income	$ 422	$ 3,843	$ 7,278	$ 10,956
Foreign currency translation adjustments	(1,560)	61	(2,111)	320
Comprehensive income (loss)	$ (1,138)	$ 3,904	$ 5,167	$ 11,276