Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net revenue:
Products	$ 132,660	$ 99,028	$ 77,022
Sales Revenue, Services, Net	18,833	19,028	17,739
Total net revenue	151,493	118,056	94,761
Cost of revenue:
Products	56,363	40,149	32,402
Service	9,020	9,772	8,076
Total cost of revenue	65,383	49,921	40,478
Gross profit	86,110	68,135	54,283
Operating expenses:
Sales and marketing	52,070	41,563	35,942
Research and development	12,874	11,232	10,733
General and administrative	14,090	12,943	12,129
Lease termination income	(4,000)
Total operating expenses	75,034	65,738	58,804
Income (loss) from operations	11,076	2,397	(4,521)
Interest and other income, net	884	323	293
Income (loss) before income taxes	11,960	2,720	(4,228)
Income tax provision (benefit)	(18,033)	143	212
Net income (loss)	$ 29,993	$ 2,577	$ (4,440)
Net income (loss) per share:
Basic (in dollars per share)	$ 2.16	$ 0.19	$ (0.32)
Diluted (in dollars per share)	$ 2.04	$ 0.19	$ (0.32)
Weighted-average number of shares used in per share calculations:
Basic (in shares)	13,873	13,225	13,960
Diluted (in shares)	14,728	13,753	13,960